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MS4 TMDL Annual Report FY19-20 I r 1.t �. ol?E G 0 � 2019 - 2020 _ _ NPDES MS4/TMDL Annual Report . . -J; •'10N. - .-- " -"ICC". .;• " - .;"-Ir. .... ..77...1-111417:;ifty..-,sq•-;.7 jj.c...„ .6 ts' ems.; 4�rj 4 .s y. - j• 4 • '''— '. . _ 1. f -.-....( -...."Ai . V110- . �' a I Credit: Lost Dog Creek,Lake Oswego,OR(S.Johnson) October 31, 2020 City of Lake Oswego, Oregon National Pollutant Discharge Elimination System Municipal Separate Storm Sewer System Annual Report Covering July 1, 2019 to June 30, 2020 Prepared for the Oregon Department of Environmental Quality October 31, 2020 Otis FOs " n V rIMP O OREGO� CITY OF LAKE OSWEGO NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) MUNICIPAL SEPARATE STORM SEWER SYSTEM (MS4) ANNUAL REPORT JuLY 1,2019-JUNE 30,2020 I,the undersigned,hereby submit this National Pollutant Discharge Elimination System(NPDES) Municipal Separate Storm System (MS4) annual report in accordance with NPDES Permit Number 101348. I certify, under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to ensure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person, or persons, who manage the system,or those persons directly responsible for gathering the information,the information is,to the best of my knowledge and belief,true,accurate, and complete. I am aware that there are significant penalties for submitting false information including the possibility of fine and imprisonment for known violations. /d/Z- & Mart Bennett, City Manager Date City of Lake Oswego TABLE OF CONTENTS 1 Introduction 1 2 Stormwater Budget 1 3 Development 2 3.1 Annexations 2 3.2 Stormwater Review 2 3.2.1 Land-Use Review 3 3.2.2 Construction Plan Review 3 3.3 Stormwater Management 4 3.3.1 Impervious Area 4 3.3.2 Public Stormwater Facilities 5 3.3.3 Private Stormwater Facilities 5 3.4 Capital Improvement Projects 6 3.4.1 Retrofit Projects 7 3.4.2 Hydromodification Projects 7 4 Stormwater Management Plan 8 4.1 Illicit Discharge Detection and Elimination (IDDE) 8 4.1.1 Spill Response and Enforcement 9 4.1.2 Industrial and Commercial Facilities 9 4.2 Construction Site Runoff Control 10 4.3 Public Education and Involvement 10 4.4 Pollution Prevention for Municipal Operations 11 4.4.1 Stormwater Conveyance Infrastructure 11 4.4.2 Wastewater Infrastructure Effects 11 4.4.3 Street Sweeping and Winter Maintenance 11 4.4.4 Pesticide Applications 12 4.5 Stormwater Facility Management 12 4.5.1 Public Stormwater Facilities 12 4.5.2 Private Stormwater Facilities 14 5 Stormwater Monitoring Program 14 5.1 Instream Monitoring 15 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page i 5.2 Wet Weather Monitoring 15 5.3 Continuous Monitoring Stations 16 5.3.1 Lost Dog Creek 16 5.3.2 Springbrook Creek 16 5.4 Total Maximum Daily Loading 19 5.4.1 Bacteria (E.Coli) 19 5.4.2 Dissolved Oxygen 21 5.4.3 Chlorophyll a and pH 21 5.4.4 Biocriteria 23 5.5 Water Quality Limited Streams 24 5.5.1 Biological Criteria 26 5.5.2 Dissolved Oxygen 26 5.5.3 Metals 26 6 Adaptive Management 27 Appendix A 2012 SWMP Implementation Status Appendix B Lake Oswego Monitoring Data Appendix C TMDL Implementation Plan, FY1920 Annual Report 56 C.1. Introduction 60 C.2. TMDL Implementation Plan Revisions 61 C.2 Program Management 61 C.3 Development 61 C.4 Water Quality 62 C.5 Temperature 64 C.5.1 Preservation of Riparian Habitat 65 C.5.2 Enhancement of Riparian Habitat 66 C.5.3 Existing Shade Protection 68 C.6 Adaptive Management 69 C.7 Other Activities 69 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page ii List of Tables Table 1. Historical and Forecasted Stormwater Budget, FY1617 to FY2021 1 Table 2. Historical and Current Annexations and Impervious Area, FY1516 to FY1920 2 Table 3. Public Stormwater Facilities Constructed by Private Development, FY1920 5 Table 4. Impervious Area Treated by Private Stormwater Facilities, FY1920 6 Table 5. Impervious Area Treated by Green Infrastructure, FY1920 7 Table 6. Capital Improvement Projects Affecting Stormwater in Lake Oswego, FY1920 8 Table 7. Spills and Illicit Discharge Investigations in Lake Oswego, FY1920 9 Table 8. Pesticides Used on City-Owned Property, FY1920 13 Table 9. Private Stormwater Facility Inspections, FY1920 14 Table 10. Summary of Wet Weather Sampling, FY1920 and FY1213-FY1617 17 Table 11. Bacterial Wasteload Allocations for Streams in Lake Oswego 19 Table 12. E. Coli Concentrations in Ball Creek and Carter Creek, 1997-2003 vs FY1920 20 Table 13. E. Coli Concentrations in Springbrook Creek, 1997-2003 vs FY1920 20 Table 14. E. Coli Concentrations at Nettle Creek, Lost Dog Creek, and Boones Ferry, 1997-2005 vs FY1920 21 Table 15. Dissolved Oxygen,VSS, and TSS Concentrations in Ball Creek and Carter Creek, FY1920 21 Table 16. Chlorophyll a and pH Wasteload Allocations for Streams in Lake Oswego 22 Table 17. Phosphorous Concentrations and pH in Ball Creek and Carter Creek, FY1920 22 Table 18. Phosphorous Concentrations and pH in Selected Oswego Lake Tributaries, FY1920 23 Table 19. Summary of Biological and Physical Characteristics of Selected Streams in Lake Oswego 24 Table 20. Streams designated as Water-Quality Limited under the Clean Water Act Section 303(d) 25 Table 21. Zinc and Lead Concentrations and Thresholds for Ball Creek and Carter Creek, FY1920 26 Table A.1. Stormwater Management Plan Metrics, FY1819 Progress 31 Table B.1 Nettle Creek at Tryon Creek, Instream Monitoring Results, FY1920 48 Table B.2 Lost Dog Creek at Lake Front Rd, Instream Monitoring Results, FY1920 49 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page iii Table B.3 Springbrook Creek at Iron Mountain Blvd, Instream Monitoring Results, FY1920 50 Table B.4 Boones Ferry Creek at Bryant Rd, Instream Monitoring Results, FY1920 51 Table B.5 Ball Creek bel Kruse Way, Instream Monitoring Results, FY1920 52 Table B.6 Carter Creek abv Bangy Rd, Instream Monitoring Results, FY1920 53 Table B.7 Wet Weather Results at Reese Rd and at South Shore Blvd, October 16, 2019 54 Table B.8 Wet Weather Results at Reese Rd and at South Shore Blvd,June 6, 2020 55 Table C.1.TMDLs for Streams in Lake Oswego's Jurisdiction 60 Table C.2. Historical and Current Annexations and Impervious Area, FY1516 to FY1920 61 Table C.3. TMDL Parameters and Example Related City Activities to Reduce Loads 63 Table C.4. Stream Temperatures at Selected Sites in Lake Oswego, FY1920 and FY1213-FY1516 64 Table C.5. Metrics for TMDL Management of Stream Temperatures 70 List of Figures Figure 1. Annexations in Lake Oswego, FY1920 3 Figure 2. Impervious area in Lake Owego, 2020 4 Figure 3. Stream Monitoring Sites in Lake Oswego 15 Figure C.1. Impervious Area in Lake Oswego, FY1920 62 Figure C.2 Properties with a Building Permit and Sensitive Lands or Within 50 ft of a Stream, FY1920 65 Figure C.3. Temperatures of Potential Cold-Water Refugia,June 2016 to September 2016 67 Figure C.4. Backyard Habitat Program Participation, FY1516 to FY1920 68 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page iv 1 INTRODUCTION The Clean Water Act (CWA) was enacted in 1972 to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters". After point sources such as industrial facilities and wastewater treatment plants were regulated as part of the National Pollutant Discharge Elimination System (NPDES) program, the USEPA found that the nation's rivers and streams were still not providing sufficient water quality to meet their assigned beneficial uses. As a consequence, the NPDES Municipal Separate Storm Sewer System (MS4) Phase I permit program was implemented in 1990 to regulate stormwater discharges from municipalities, counties, and other entities that met the MS4 permit thresholds of a population of 100,000 people or in an urbanized area. While the City of Lake Oswego (City) only had a 1995 population of 34,000 people (39,500 currently), it was considered to be in an urbanized area along with other Clackamas County jurisdictions. The City received its first NPDES MS4 Phase I permit from Oregon Department of Environmental Quality (DEQ) in 1995 as a co-permittee of Clackamas County. The Phase I Clackamas County permit (#101348) includes Clackamas County, Oak Lodge Sanitary District, and the cities of Lake Oswego, Milwaukie, Gladstone, West Linn, Oregon City, Wilsonville, Happy Valley, Johnson City, and Rivergrove. The City's current permit was issued in March 2012 and is currently on administrative extension. Past annual reports, assessments, and other related regulatory documents can be viewed on the City website at httb://www.ci.oswego.or.ushublicworkshermits-blans-and-reborts. 2 STORMWATER BUDGET The City's stormwater program is funded primarily through monthly stormwater fees and is based on the number of equivalent service units (ESU) assessed for the property. ESUs, the average impervious area for residential properties, is 3,030 ft2. The monthly stormwater fee for a single family/duplex residential property was$16.49 in FY1920 and is$17.64 in FY2021. Stormwater system development charges(SDCs) are used to alleviate capacity issues but, since the City is largely developed,they comprise a small portion of the total budget. SDCs were $162 per ESU for FY1920 and are$164 per ESU for FY2021. In FY1920, the City spent $4.45 million dollars on stormwater projects, maintenance, and compliance programs with about half of those funds spent on capital improvement projects(see Table 1). In FY2021, the City expects to spend $4.71 million dollars with about 30% of the funds set aside for capital improvement projects. Table 1. Historical and Forecasted Stormwater Budget, FY1617 to FY2021 FY1617 FY1718 FY1819 FY1920 FY2021 Actual* Actual* Actual* Actual* Budgeted Program Operations $ 539,461 $ 881,585 $ 900,814 $ 875,363 $ 1,001,000 Program Management $ 1,445,959 $ 2,302,461 $ 1,420,658 $ 1,335,694 $ 2,210,393 Capital Projects $ 192,255 $ 1,414,601 $ 1,707,052 $ 2,243,060 $ 1,498,000 Total $2,177,675 $4,598,647 $4,028,524 $4,454,117 $4,709,393 *These numbers are not audited City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 1 Table 1 includes budgets from Engineering and Public Works. They do not include related programs such as the portion of the Planning Department's budget used for its Urban Forestry programs and code enforcement of sensitive lands and tree canopy; the budget from the Parks Department that is used for maintenance of City-owned properties and Master Plan development; and funds disbursed through partnerships such as the Backyard Habitat Program, Neighborhood Grants, and the Habitat Enhancement Program. These programs can positively affect water quality and some are used for stormwater education as well as other objectives. 3 DEVELOPMENT With the current MS4 permit in administrative extension and an expectation that it will be renewed in FY2021, the City made no changes in the stormwater code nor in the documents addressing stormwater management. There were no comprehensive plan changes nor zoning changes that affected stormwater discharges. The urban services boundary did not change nor is it expected to change in FY2021. No concept planning or activities were completed in FY2021 that were associated with urban growth boundary changes or land annexation. 3.1 Annexations Eight properties were annexed in FY1920 (see Table 2)with all but one of them located on the west side of the City (see Figure 1). Of those 8 acres, 1.1 acres are impervious (13%). Five of the properties are zoned as R7.5 (7,500 ft2), one property is zoned as R-10, and one is zoned as R-15. All annexed into the City to connect to the public wastewater system and 5 indicated they were interested in further development of the property. Three of the annexations were properties that already have multiple tax lots; two properties were comprised of 2 tax lots and one property was comprised of 3 tax lots. Of the lots that cannot be further subdivided,two are zoned R7.5 and one is zoned R-10. As of October 1, 2020, there are two known annexations for FY2021. One is comprised of two tax lots totaling 0.42 acres and zoned as R-10. The other is 0.28 acres and is assumed to be zoned R7.5. Table 2. Historical and Current Annexations and Impervious Area, FY1516 to FY1920 #of Impervious Impervious Impervious Properties Acres Area Created, Area in City Area in USB vs City Year Annexed Annexed Acres Limits,Acres USB,Acres Limits,Acres FY1920 8 8.2 1 2,393 2,584 191 FY1819 13 6.6 7 2,286 2,570 284 FY1718 9 4.0 5 2,279 2,567 288 FY1617 11 6.6 20 2,274 2,561 287 FY1516 27 22.0 19 2,200 2,555 355 3.2 Stormwater Review Private development is governed by the City's municipal code, stormwater management manual (SWMM), and engineering design standards. There were no changes to the City's stormwater code or SWMM in FY1920. An update to the SWMM was started in FY1920 and will be completed in FY2021. The engineering design standards were created in FY1920 and adopted in June 2020. In regard to stormwater, the engineering design standards primarily cover conveyance structure requirements with the SWMM still the primary driver for stormwater management and stormwater facility requirements. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 2 '� 2 AN 19-0004 raa s, ' 0 -k at. r" h Dr i MI 4 +'PAJbx C. 2e ill; I . Y 4� `r A�gn At nn.... - V-- SW Dnr4 w ea+a nc I u 98 a 3 AN 19.0006 1, 1 ® p ke g w L.a o vol.LA. cmW ne 0 0,0 a g f ,e `g% AN 20-0001 1- " i ouvr- AN 19-0007 1% ilit: p.4111F! ' w 440.111.•: ill AN 19-0005 R'4 ts�f 8 40_ .7, i. t — i � A GROWIAN Rd 1 rild - 0 P° .4a^ fla SW mangy '� `�� G 3� s ow. Rd ,, Fery a' _or_ lk % pi ... l,t Ind 440 "1#1441 ' I Annexations Adopted f: - z p ITP- F. ; y 2019-2020 AN 20-0002 2020-022013 .0 s° 0 0.35 0.7 Miles I 1 Figure 1. Annexations in Lake Oswego, FY1920 3.2.1 Land-Use Review Projects are required to provide onsite stormwater management for the 10-yr 24-hr design storm to the maximum extent possible. Projects that create or replace 3,000 sq ft or more of impervious area are expected to meet flow requirements as well as water quality requirements. No flow requirements are required if large projects discharge directly, or through manmade infrastructure, to the Tualatin River, Oswego Lake, or the Willamette River. There were 26 development applications that underwent the land-use process in FY1920 including two commercial projects and two institutional projects. The commercial projects were an office building for an adjacent car wash and a parking lot replacement. The institutional projects included a small office building for a church and the City's 10th Street Water Improvement Project (pump station). None of the commercial and institutional projects are expected to be subject to a DEQ 1200-Z permit. 3.2.2 Construction Plan Review Staff reviews private development projects for compliance with the stormwater requirements. In FY1920, staff reviewed 227 construction plans and, of those, 83 were required to treat their stormwater. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 3 Eleven of the construction plans that were reviewed were commercial or industrial projects. Of those, seven used private UlCs for stormwater management and four used raingardens. A draft maintenance plan is required for all proposed stormwater facilities. Projects using infiltration trenches, infiltration galleries, and drywells are required to show that they have started the process of obtaining DEQ approval of their underground injection controls. 3.3 Stormwater Management The MS4 permit requires the City to mimic pre-construction hydrology to the maximum extent practicable with green infrastructure(GI)as the preferred strategy. The City's SWMM complies with this requirement by requiring onsite infiltration of the 10-yr 24-hr design storm to the maximum extent practicable and to use a curve number of 70 when determining the amount of runoff created by a project. 3.3.1 Impervious Area The City currently contains 11.4 sq mi (7,320 acres)within its boundaries with 33%of the area (3.7 sq mi) considered to be impervious (see Figure 2). When including the impervious area in the City's urban services boundary,the impervious area is 4 square miles. Both are similar to last year's percentages which reinforces the perception that much of the City is already developed and that current development is either infill, partitions, or redevelopment of already existing impervious area. i i Ll 1 ,,4 i i ._, ,it 'LitiL-17,---1,..,-;*(,. ;49,,,,, v,-', t• 4-",ty. - ,...e40,--. ' ,.re - . .'; ... ,--':w. - .1-r6.7...;..-,,iti,y, itg. •,,,,,,:- .,,,),,.,,,..0 .i? , . 0,-- - . 4.1 It, ., - . .. . lke,,,,,, ,,,,Ts' L/ , .. !_;,, ,r.-.4r.-,,,.- -..-4 ., ..,, 0:: • — - . r. - -' i-- _ , ,, t,, _-,. ..„..-,„.._,__,71._. p.),-;;_.:_- t...t.u. ..,',, , - A.,,, ••, , I. •;.• „74,--,- , 1 1 Ili ,,. ,,'-‘,7-P-i, '',..t.44:7,,*).14,... .6 4,41, -1-•,3,.. 47fp. ,,hi,kit,,c4g,Pri4V,E,i;',.•46':-._ ) ' io., , ki4 ,4".,..„ , . l „,, .. ,'" * .:2.3 � y��, `ter '�: r �- 1,--� L '� r�1y' siN'!' Yoe '� .1�' j _ �+]"yj'7 nfr4 4411 • 1%flir -'''‘• 1."V.'.. yk �`? a -T 4104... w � x0 y Lo. -•• 442Igiq .'"--1 --,•• .4- .4-,,,,.:A.,Lr iesm ---- :,.' .,... .' .,,-,,gro-g-.141-4... " 'fi: `:, gog, NY . ,,;.,--,,, ) , .- ..,,,•11,-. „4 - ,,• -;,-,..i.v.71,4*1 to, ite , 1141 : it. . .' • tifipr..,,4y '••• *Jr _ .�.'y'� '4 _ ` impervrou s rtace wm n Lake oswegu city Llmlts r-�,,� [ �' '� -Impervious Surfaces within Urban Services Area �_-�- ^, r} .. Urban Services Bavnda ry J !__k k �— J Leke Oswego Boundary 'y. 1— a� Park or open Space 1 ,cis .,�,..,,s,,,a...�,�.nes P .d.,�._ LLL Figure 2. Impervious area in Lake Owego,2020 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 4 3.3.2 Public Stormwater Facilities Proposed developments must meet the requirements of the SWMM with some projects required to construct public stormwater facilities. In FY1920,three public stormwater facilities(two filtration planters and one raingarden)were constructed which will treat 13,373 sq ft of impervious area (see Table 3). The majority of the treated area will benefit the Tualatin River watershed. Table 3. Public Stormwater Facilities Constructed by Private Development, FY1920 Springbrook1 I I I Willamette Facility Type Oswego Lake Creek Tryon Creek Tualatin River River Total By Type %of Sq ft Acres Sq ft Acres Sq ft Acres Sq ft Acres Sq ft Acres Acres Total Filtration Planter - - - - - - 12,373 0.28 - - 0.28 90 Raingarden 1,350 0.03 - - - - - - - 0.03 10 Total 11,350 0.03 I I I I - 112,373 0.28 I - I - 0.31 1100 I 3.3.3 Private Stormwater Facilities Stormwater facilities were constructed for 82 private projects treating 536,000 sq ft of impervious area in FY1920 (see Table 4). Commercial properties, including multi-family projects, created and/or replaced 207,000 sq ft. Institutional properties, i.e. schools, treated 65,000 sq ft. Single-family residential properties created and/or replaced 264,000 sq ft. Most of development occurred in the Oswego Lake, Tryon Creek, and Willamette River watersheds. As in previous years, the primary stormwater facilities chosen for onsite treatment were filtration planters, dry wells, and StormTech Chambers (80%). Surprisingly, infiltration raingardens were used to treat the most stormwater in the Tualatin River Basin. Some developments do not create enough impervious area to trigger the stormwater requirements (see "below threshold" in Table 4). This may be because they do not trigger the 1000-sq ft threshold or they may discharge directly to Oswego Lake,the Tualatin River, or the Willamette River(see Section 3.2.1). In FY1920, only 4.9%of the impervious area created in the city was untreated which is similar to FY1819. The NPDES MS4 permit emphasizes green infrastructure (GI) as the preferred method of stormwater treatment. GI includes planters, raingardens, porous pavement, and pervious pavers. In FY1920, almost 28%of the stormwater from impervious area was treated using GI. When broken into single-family residential and other types of development, it can be seen that GI accounts for over 50%of the stormwater treatment for single-family residential (see Table 5). Other types of development use GI to treat only 2.5%of the stormwater generated by their projects. It is not surprising given the tighter space restrictions of commercial, industrial, and other types of non-single family residential projects. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 5 Table 4. Impervious Area Treated by Private Stormwater Facilities, FY1920 Oswego Springbrook 1 Tryon Tualatin Willamette Facility Type Lake Creek Creek River River Total By Type Acres Acres Acres Acres Acres Acres %of Total Raingarden, Infiltration 0.27 - 0.22 0.15 0.16 0.80 6.5% Raingarden, Filtration 0.10 - - - - 0.10 0.8% Bioswale - - - 0.05 - 1 0.05 0.4% Planter, Infiltration 0.03 - - - 0.18 0.21 1.7% Planter, Filtration 0.94 0.35 0.42 0.11 0.31 2.13 17.3% Porous Pavement - - - 0.01 - 1 0.01 0.1% Pervious Pavers 0.09 - - 0.02 0.03 0.14 1.1% Infiltration Trench - - - - - - - StormTech Chambers 1.30 0.25 1.60 0.10 2.19 I 5.44 44.2% Dry Wells 1.68 0.13 0.31 0.14 - 2.26 18.4% StormFilter - - - - 0.21 0.21 1.7% Sheetflow 0.06 - 0.02 0.02 0.03 0.13 1.1% Detention Pond - - 0.10 0.05 - 0.15 1.2% Retention Pond - - 0.06 - - 0.06 0.5% Below Threshold 0.41 0.10 0.05 0.02 0.03 0.61 4.9% Total 4.88 0.83 2.78 0.67 3.14 12.3 Green Infrastructure 1.43 0.35 0.64 0.30 0.69 3.4 28% % Green Infrastructure 29.2% 42.0% 22.8% 44.4% 21.9% Percent Untreated 8.4% 12.3% 1.8% 3.1% 0.8% Because infiltration creates shallow groundwater (interflow) that replenish streams during the dry summers, it is expected that continuing to emphasize infiltration facilities and onsite stormwater treatment will greatly assist those watersheds that have a temperature TMDL. Focusing on infiltration facilities, it is shown in Table 5 that 72% of the stormwater generated by development within the City infiltrates into the ground to provide summer baseflow for the City's streams. 3.4 Capital Improvement Projects Capital improvement projects are often comprehensive in nature; many projects will repair, replace, or upgrade wastewater, water, stormwater, and pavement within the same project in order to take advantage of common costs and reduce transportation delays. Many projects are delayed or fast-tracked depending on when funding is acquired, information on current conditions, acquisition of right-of-way, or the ability to provide multi-utility improvements. Seven CIP projects resulted in the construction of stormwater facilities or additional pretreatment. They were located in the Tryon Creek, Oswego Lake, and Tualatin River watersheds (see Table 6). City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 6 Table 5. Impervious Area Treated by Green Infrastructure, FY1920 Non-Single Family Single Family Residential Residential Total %Green %Green %Green Watershed Acres Infrastructure Acres Infrastructure Acres Infrastructure Oswego Lake 2.44 58.3% 2.43 0.0% 4.87 29.2% Springbrook Creek 0.80 43.6% 0.03 0.0% 0.83 42.0% Tryon Creek 1.34 47.5% 1.45 0.0% 2.79 22.8% Tualatin River 0.63 41.4% 0.05 84% 0.68 44.5% Willamette River 0.84 67.8% 2.29 5.0% 3.14 21.9% Total 6.05 56.1% 6.25 2.5% 12.31 27.6% 3.4.1 Retrofit Projects The 2015 Retrofit Assessment identifies several retrofit criteria: protection of private and public infrastructure, repair or maintenance of existing infrastructure; improvement of water quality or natural resources, regulatory requirements, or the ability to be combined with another CIP project(multi-utility). The 10th St Water Improvements (converting a reservoir to a pump station) improves water quality and protects public infrastructure with the construction of a raingarden. The Wembley Park Rd project protects private infrastructure from road runoff; repairs and maintains existing public infrastructure; reduces flooding; improves natural resources and water quality; and is a multi-utility project (street, water, and stormwater). The Marylhurst Pump Station project improves water quality and natural resource values and is a multi-utility project (wastewater and stormwater). The Lakeview Blvd Realignment project improves water quality and is a multi-utility project (stormwater and street). The D Avenue project improves water quality and natural resource values; protects private and public infrastructure; and is a multi-utility project (stormwater and street). The Pavement Maintenance project improves water quality, is a multi-utility project (stormwater and street) and protects private and public infrastructure. 3.4.2 Hvdromodification Projects Two capital improvement projects addressed sources of hydromodification in FY1920 (See Table 6). The Lakeview Blvd Realignment project included an infiltration pond to treat and detain stormwater from approximately 0.28 acres of previously-untreated impervious area. The project also added 5 catchbasins with 3-ft sumps and WQ snouts. It should result in less stormwater entering the public system. The D Avenue project treated 3.34 acres of previously-untreated impervious area by constructing 12 swales and 27 raingardens which will increase water quality and reduce stormwater volume to Tryon Creek. In addition, the project reduced the number of outfalls and rerouted the final outfall to a lower section of the creek thereby reducing the length of stream affected by hydromodification from the City's stormwater. The Wembley Park Rd project includes the construction of treatment facilities (primarily Contech StormFilters)and the reconstruction of several outfalls to enhance energy dissipation and reduce streambank erosion. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 7 Table 6. Capital Improvement Projects Affecting Stormwater in Lake Oswego, FY1920 Status Watershed Project Name Project Description* WQ Impact* Reduced Hydromodification Tryon Constructed 39 new vegetated Reduced Sediment/Trash Completed Creek D Avenue stormwater facilities. Increased Water Quality Constructed infiltration pond for 0.28 acres of previously untreated impervious area. Added 5 Reduced Hydromodification Oswego Lakeview catchbasins with 3-ft sumps and WC Reduced Sediment/Trash Completed Lake Realignment snouts. Increased Water Quality Canal Circle Decommissioned UIC. Added Reduced Sediment/Trash Oswego UIC Contech StormFilter before Reduced Proximity to GW Completed Lake Decommission connection to public system. Increased Water Quality Tryon Country Club Reduced Sediment/Trash Completed Creek Road Two inlets added with WQ Snouts Increased Water Quality 2019 Tualatin Pavement Added 3-ft sumps to 6 inlets. Added Reduced Sediment/Trash Completed River Rehabilitation WQ snouts to 5 of the 6 inlets. Increased Water Quality 2019 Added 23 inlets/catchbasins with 3- Oswego Pavement ft sumps. Added WQ snouts to 14 Reduced Sediment/Trash Completed Lake Rehabilitation of the 23 inlets/catchbasins. Increased Water Quality Reduced Hydromodification Almost Tryon 10th St Water Constructed new raingarden and Reduced Sediment/Trash Completed Creek Improvement reduced impervious area footprint. Increased Water Quality *WQ=Water Quality; UIC=underground injection control;GW=groundwater 4 STORMWATER MANAGEMENT PLAN The City's Stormwater Management Plan contains the seven minimum measures required in the MS4 permit along with measurable goals and tracking measures to assess progress(See Appendix A). Progress towards meeting post-construction requirements was discussed in Section 3 and a progress summary of the remaining measures is discussed in this section. Additional details are provided in Appendix A. 4.1 Illicit Discharge Detection and Elimination (IDDE) The IDDE program includes a spill response plan, spill and citizen complaint response, outfall monitoring, wastewater conversions from septic systems,and notifying DEQ of businesses in the city limits which may require an industrial stormwater permit (1200-Z). There were no changes in the Spill Response Plan for FY1920. Public Works and the Fire Department provide a combined staff training for spill response. In FY1920, 25 staff from Public Works and 50 staff from the Fire Department participated in the event which covered spill response, stormdrain blocking, hazardous material mitigation, and team development. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 8 There were no cross-connections discovered between the wastewater and stormwater systems. There were 37 decommissioning of septic systems with subsequent connection to the public wastewater system in FY1920. One of the properties in the Springbrook Creek watershed took advantage of the Bancroft Loan Program to complete the conversion. 4.1.1 Spill Response and Enforcement The Lake Oswego Fire Department responded to 18 spills with only 1 entering the stormwater system (see Table 7). Public Works was requested to assist with cleanup of the one incident. TVF&R was not called out for any incidents. Engineering Staff responded to 5 incidents in FY1920 with three resulting in citations. Table 7. Spills and Illicit Discharge Investigations in Lake Oswego, FY1920 SW System Date Watershed Type* Action* Affected?* 7/2019 Tualatin River Concrete washwater Required cleanup. Citation issued Y 7/2019 Tualatin River Sediment from dredging Required Cleanup. Citation Issued Y 7/2019 Tryon Creek Sediment from Construction Required Cleanup. Citation Issued Y Springbrook 7/2019 Creek SSO Cleanup by staff. OERS#2019-1700 Y 7/2020 Tualatin River SSO Cleanup by staff. Y 8/2019 Tryon Creek Paint Required Cleanup. N Required Cleanup. Did not reach stormwater system. OERS#2019-2424; 8/2019 Willamette River Fuel Spill NRC#1258058. N 1/2020 Willamette River SSO Cleanup by staff. OERS#2020-0261 Y 1/2020 Oswego Lake SSO Cleanup by staff. OERS#2020-0151 Y 2/2020 Oswego Lake SSO Cleanup by staff. OERS#2020-0334 Y Cleanup by staff—only 1 entered the Various Various 18 Auto Accidents with Spills stormwater system Y *SSO=Sewer System Overflow;OERS=Oregon Emergency Response System;NRC=National Response Center;SW=stormwater • The City currently monitors three priority sites for illicit discharges during the dry season. Two of the sites have flow each year, however field measurements taken at the sites in FY1920 were not indicative of illicit discharges. The third outfall had flow which was tested for field measurements and E. Coli. The results were indicative of groundwater and not an illicit discharge. 4.1.2 Industrial and Commercial Facilities Two commercial development proposals successfully completed the private development land-use process. One was an office building for a car wash and the other was a parking lot replacement. Eleven commercial or industrial construction plans were reviewed in FY1920. Two were in the Tryon Creek City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 9 watershed, three were in the Willamette River watershed, one was in the Springbrook Creek watershed, and the rest were in the Oswego Lake watershed. No notification letters were sent to businesses in regard to obtaining a DEQ 1200-Z permit. In January 2020, in response to a phone call inquiry, a facility(SIC Code 3841-Surgical and Medical Instruments and Apparatus) was requested to contact DEQ's 1200-Z program to determine if they needed a permit. A follow-up phone call was made to the DEQ 1200-Z Program Manager so they would expect an inquiry or application from the business. 4.2 Construction Site Runoff Control Construction site runoff control, or erosion and sediment control (ESC), is an important program for reducing total suspended solids in streams within the City's jurisdiction. The City currently has a 500 sq ft soil disturbance threshold for ESC permits. The City also requires an ESC permit for projects that are within 50ft of a lake or waterway. The City issued 155 ESC permits in FY1920. Most were associated with a residential building permit. Initial ESC inspections were conducted at 84 projects. There were 76 intermediate ESC inspections and 25 final ESC inspections. Thirty projects required more than three inspections and staff issued four citations. 4.3 Public Education and Involvement The City is a member of several regional stormwater outreach groups such as Regional Coalition of Clean Rivers and Streams (RCCRS), the state-wide Clean Rivers and Streams (CRS), the Tualatin Basin Public Awareness Committee (TBPAC), and a group that works with KPTV to provide public service announcements (PSAs). In addition, staff provide stormwater education and outreach through its social media (Facebook, Twitter, and Instagram), a newsletter (HelloLO), calendar, water audits, and a stormdrain marking program. The RCCRS staffed a booth with local watershed councils at the Big Float in July 2019 to engage approximately 500 people in salmon-friendly practices and watershed information. They also sponsored a video contest across the metro area for high school and middle school students. The video entries covered hazardous waste disposal practices, pet waste disposal, pesticide and fertilizer use, waste oil disposal, littering, and Leave No Trace. The 36 entries that were received were put on the RCCRS' YouTube page where they reached more than 4,000 people. The group has a website and is active in social media with one post per week on average for Facebook, one tweet per week on Twitter, and an Instagram post on average every other week. Facebook ads bought and promoted by the RCCRS include information on tire recycling, algal blooms, car washing, pesticide effects on rivers, and others. The ads reached over 200K people with more than 190K people engaging with the messages (liking, commenting, or clicking on links for further information). As part of the KPTV regional group, citizens were educated about minimizing fertilizer and pesticide use; car washing practices, and sweeping surfaces instead of using pressure sprayers. There were 713 public service announcements seen by 13.5 million views. The PSA webpage on the KPTV website had 5,337 page views and the PSAs had 16,262 video views on KPTV's Facebook page. Overall,the campaign reached 16.6 million viewers. Normally, staff provide landscaping/water conservation audits from May to October however, in March 2020,the program was suspended due to COVID-19 concerns. Even with the suspension, staff were able to successfully complete 18 audits from July to October of 2019 including one audit for a large multi-family residential commercial property. The audits include conversations about responsible water management City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 10 and the impacts of overwatering, improper plant selection, and excessive fertilizer use on creeks,streams and wetlands.To compensate for the reduced public activities,staff have increased efforts to educate the public via the Water Conservation Program's website and in social media efforts especially the"Nextdoor" social media platform.The City offers free hose timers, rain sensors,soil test kits,and soil moisture probes as well as several brochures providing information on natural gardening, hazards in the home, and safe disposal of household chemicals and medicines. All items and brochures are accessible to the public by requesting them through telephone, email, or the City's website. In FY1920, markers were placed at 12 catchbasins and 11 UlCs throughout the City. No stream crossing signs were installed in FY1920. Several developers and landscape contractors were alerted to the Clean Water Services class on maintaining vegetated stormwater facilities. They and others were also told of the online version of the class after COVID-19 restrictions went into effect. Several people indicated that they were interested or had signed up for the class. A public event was held to provide information for the Wembley Park Rd project in November 2019 and an event was held for the 10th Street Water Improvement project in January 2020. Manuals, permits, annual reports, and other stormwater-related documents are available to the public through the City's website. There were no comments on these materials in FY1920. 4.4 Pollution Prevention for Municipal Operations The MS4 permit requires the City to inspect and maintain its stormwater infrastructure including repairing or replacing non-functioning components. In addition, the City is required to provide information on pesticide applications at City facilities, including parks,and on its street sweeping and winter maintenance programs. 4.4.1 Stormwater Conveyance Infrastructure The City's stormwater system contains over 132 miles of stormline, almost 3,000 manholes, and over 4,000 catchbasins. Open sections of the system include 13 culverts and 190 ditches. Public Works reported that staff cleaned and inspected 1,144 catchbasins and 195 manholes. Staff inspected 475 ft of stormline and cleaned 1,500 ft. Staff installed 46 new catchbasins in FY1920 and repaired 2,080 linear feet of ditches. Public Works keeps a list of the most problematic inlets as indicated by flooding complaints. Of the inlets on the list, 92 were inspected and cleaned 15 times in FY1920. Another 83 inlets on the list required cleaning 16 times. 4.4.2 Wastewater Infrastructure Effects The City recently completed an I & I study in part of the Oswego Lake stormwater basin. The project included recommendations for 19,231 feet of wastewater line. As part of an I & I reduction project in the Springbrook Creek stormwater basin, staff investigated over 82,000 feet of wastewater line, repaired 830 ft of the main line, and repaired 281 ft of wastewater laterals. 4.4.3 Street Sweeping and Winter Maintenance Street sweeping is used to reduce total suspended solids, bacteria, nutrients, and metals in stormwater. In general, commercial streets are swept every week while major commuter routes are swept once a City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 11 month. Curbed residential areas are swept four to six times a year. Over 5,200 miles of streets were swept in FY1920. The City does not separate the street sweeping debris from the stormwater infrastructure debris. In FY1920,the City collected approximately 1,900 cu yd of combined debris from the streets and stormwater infrastructure. The results from the TCLP analysis completed on a debris sample allowed the City to dispose of the debris in the Wasco County landfill. The City's canopy coverage exceeds 80% and, as such, the fall season presents challenges in regard to flooding caused by leaves blocking inlets and catchbasin grates. In FY1920, staff removed almost 1,500 cu yds of leaf debris. The public is encouraged to properly dispose of leaves in yard debris bins provided by their trash collection service and is reminded by posts in the City's social media and in newsletter articles. The City pays for dropoff boxes for leaf collection when requested by citizens. No requests were received in FY1920. Regional stormwater groups, of which the City is a member, also provide public service announcements and social media posts reminding people to uncover their storm drains to prevent flooding. Elevations in the City range from sea level along the Willamette River to approximately 1,000 ft in the northern section (Nansen Summit) to 98 at Oswego Lake in the middle of the City to over 700 ft in the southern section (Cook's Butte and Crestline Drive). These elevation changes create challenging public safety situations when winter weather occurs in the region. The City uses gravel and magnesium chloride to increase safety on the streets when ice and/or snow are forecast. In FY1920,the City used 3,000 gallons of an anti-icer containing magnesium chloride. 4.4.4 Pesticide Applications The City uses a range of pesticides along the Willamette Trolley line, in City parks and natural areas, and in street medians. To reduce the amount of pesticides used on City-owned property, the City's Park Department has improved the timing on weed removal, added mulch to bare areas, and increased the use of manual removal in landscaped areas. Public Works has been actively reducing the amount of post- emergence herbicide used on City-owned properties through the use of mulch and manual removal. The City applied 215 gallons and 296 pounds of pesticides in FY1920 (see Table 8). The active ingredient in most of the products was triclopyr,glyphosate,trifluralin, and pentachloronitrobenzene. In FY1920, 75 staff and contractors maintained their ODA licenses for pesticide applications. 4.5 Stormwater Facility Management The City inspects and maintains public stormwater facilities. In addition, it also requires that private stormwater facilities remain functional through periodic inspection and maintenance. Staff add public stormwater facilities to the GIS (LO Maps) when as-builts are submitted at project completion. Private facilities are added when developers submit site plans and/or as-builts. 4.5.1 Public Stormwater Facilities Maintenance by staff for public facilities primarily consists of removal of invasive species and debris. Filter vaults are cleaned by an outside contractor. In FY1920,three filter vaults were cleaned by the contractor. Staff maintained 5 detention ponds and 24 stormwater planters in FY1920. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 12 Table 8. Pesticides Used on City-Owned Property, FY1920 Pesticide Name Active Ingredients Gallons Pounds Department)I Affirm Polyoxin D zinc salt 11.3% - 3.6 P 1 Cheetah Pro Glufosinate ammonium (24.5%) 17.5 - P, PW Dryphosate 75 SG Glyphosate(75.7%) 2.1 - E Garton 3A Triclopyr(44.4%) 9.8 - P Glyphosate 4 Plus Glyphosate(41%) 2.0 - E Glystar Plus Glyphosate(41%) 1.4 - PW 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo- P Imazapyr 1H-imidazol-2-yl]-3-pyridinecarboxylic acid) (52.6%) 0.1 - Instrata Propiconazole 4.7% Fluidoxinol 1.2% 5.0 - P Landmark XP Sulfometuron methyl (50%) and Chlorsulfuron (25%) 0.5 - E Lesco Prosecutor Glyphosate(36.5%) 2.3 - PW Tri-isopropanolammonium salt of 2-pyridine Milestone carboxylic acid,4-amino-3,6-dichloro-(40.6%) 0.8 - E Polaris Imazapyr(27.7%) 0.2 - PW Carfentrazone-ethyl, 2,4-D, Mecroprop-p acid, Quicksilver Dicamba acid (21.3%) 0.1 - P Ranger Pro Glyphosate N-(phosphormethyl)glycine(41%) 1.3 - P Razor Pro Glyphosate(41%) 6.3 - PW Reckon 280SL Glufosinate ammonium (24.5%) 2.0 - E Rodeo Glyphosate(53.8%) 72.2 - P Ronstar G Oxadiazon (2%) 0.1 3.0 P Roundup Pro Glyphosate(41%) 0.6 - P, PW Roundup Quikpro Glyphosate(73.3%), Diquat(2.9%) - 4.0 PW Secure Fluazinam 40% 0.5 0.0 P Snapshot Trifluralin (2%) - 135.0 P 2,4-D 28.57%; Mecoprop-p acid 5.88%; Dicamba Speedzone acid 1.71%;and Carfentrazone-ethyl .62% 2.5 - P Sureguard Flumioxazin (51%)(3grams=1 teaspoon) 1.3 0.2 P Tahoe 3A Triclopyr(44.4%) 15.3 - PW Transline Clopyralid (40.9%) 0.4 - P Turfcide Pentochloronitrobenzene 40% - 150.0 P Vastlan Triclopyr choline(54.7%) 71.0 - P Total 215.4 295.8 1: E=Engineering, P=Parks and Recreation, PW=Public Works City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 13 4.5.2 Private Stormwater Facilities The City has historically inspected private stormwater facilities on a complaint-driven basis. In FY1819, the City updated its policies and procedures to provide a uniform approach to the program and, in FY1920, the program was approved and inspections started for private stormwater facilities. COVID-19 restrictions limited the number of stormwater facilities that could be inspected before the fiscal year ended, however nine properties had their stormwater facilities inspected in FY1920(see Table 9). Seven of the properties finished construction in 2018 and one finished in 2017 and one finished in 2019. Overall, UlCs(infiltration galleries, infiltration trenches, and drywells) constituted the majority of the inspected facilities as well as the amount of impervious area treated by the facilities. Two properties only required one inspection. None required three inspections and none received citations. Table 9. Private Stormwater Facility Inspections, FY1920 Year Impervious Area Watershed Constructed Facility Type Treated,sq ft Oswego Lake 2018 StormTech Chambers 9,951 Oswego Lake 2018 StormTech Chambers 4,739 Oswego Lake 2017 StormTech Chambers and Pervious 3,371 Pavers Springbrook Creek 2018 Filtration Planter 8,610 Springbrook Creek 2018 StormTech Chamber 4,942 Springbrook Creek 2019 StormTech Chamber 10,595 Oswego Lake 2018 Infiltration trench and Pervious Pavement 4,824 Oswego Lake 2018 Infiltration Trench 3,225 Oswego Lake 2018 Infiltration Trench 3,857 Total 54,114 I 5 STORMWATER MONITORING PROGRAM As part of its MS4 permit, the City collects monthly instream water samples for a variety of parameters such as metals, nutrients, hardness, and bacteria. In addition, the City collects flow data and other field parameters such as pH, dissolved oxygen, stream temperature, and conductivity. Each quarter, the City also collects samples for cations, anions, and organic carbon at its six sites. Samples from storm events are collected for the same parameters as the monthly instream effort. The City maintains continuous monitoring stations at Lost Dog and Springbrook Creek. The City also provided $1,990 in FY1920, in collaboration with other permittees and the USGS,to operate and maintain the USGS hydrological station (14207500) on the Tualatin River at West Linn. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 14 5.1 Instream Monitoring Monthly sampling is conducted at six sites (see Figure 3). Three of the sites discharge into Oswego Lake, two discharge to Fanno Creek (a tributary of the Tualatin River), and a third discharges to Tryon Creek (a tributary of the Willamette River). Appendix B contains detailed data from the instream monitoring effort. ,i--- To Portlond -S Po a t l� C'} ���--o r Locations of Required Water -, Ry 1 \-Quality Monitoring _ eo°—I °-' m Station Type&Obligating Permit I l c j/ * Instream UMW(f �� Wet Weather[MS4] 1 " b Is ly C, , I CiPE/ 0 Continuous[rMDLI -.� ' "VOLNTRVCLUE, —r f !"°°' i , . �v� Co.e � ,�.{ h Streets 44 �>�� �/0 0 �, j -A AVE Water Bodies .A i- •� -_ ' - .- J Streams r..;y� ,Aiii f . P Wetlands .7a:;_r____1 *w�•— � � :a+ USB&City Limits it cPler take , � ,, �; j ; a Aim - v j /r' yri- �!�] II .e m `tl BERGIS RD � 7 rI � r* IEANRD �% � • p/ _._ / le ,i--, --,-- i >- } z�',L. s ViP' 1 7 To West Li b -, �� r. CHILD Qc p' qO9 I CS oRD F • 4 „..-1 ' 11,\\ , Dual ^ o sg. ,:,���) atin River / ,,� ' �# _ /f� �..I` tTo Tualatin y NAU_ig83_ ARN_StatePl ne_ r on-:oI' sue• V Projecton:aam... -• 7744�; , �� 0. �!. 25 ".y� i oat from RLS,DOGAMI City of Lake swego;Anne hrkt.on.g • G 1,•' . • o._, Miles Figure 3. Stream Monitoring Sites in Lake Oswego 5.2 Wet Weather Monitoring Each year,the City collects stormwater samples from two sites in the Oswego Lake watershed during rain events that provide at least 0.1 inches of precipitation. Detailed water quality data associated with the monitoring effort is available in Appendix B. The wet weather site on Reese Road is in an urbanized area with many commercial businesses. It receives runoff from Boones Ferry Rd which is a major arterial street in the City and has been undergoing a major reconstruction in FY1920 and FY2021. The wet weather site on South Shore is primarily residential with schools, Luscher Farms, and a golf course in its watershed. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 15 As shown in Table 10, the concentrations for many parameters at the Reese Rd site were below FY1213- FY1516 concentrations. Exceptions were the maximum concentrations for alkalinity, total dissolved solids, and dissolved zinc. For field parameters, water temperatures were higher, dissolved oxygen concentrations decreased, and pH remained similar to FY1213-FY1516 ranges. The concentrations for many parameters, except maximums, at the South Shore site were elevated when compared to FY1213-FY1516 concentrations. Exceptions were concentrations for nitrate and total dissolved solids. In regard to field parameters, water temperatures were higher however dissolved oxygen and pH levels remained similar to FY1213-FY1516 ranges. 5.3 Continuous Monitoring Stations The City upgraded the continuous monitoring stations in 2018 and 2019. In 2018, both stations received new submersible pressure transducers to measure stage and YSI EXO-3 sondes to measure turbidity, dissolved oxygen, pH, conductivity, and temperature. Crest-stage gages were installed in 2018 (Springbrook Creek) and 2019 (Lost Dog)to verify peak flows. A new staff gage was installed in October 2019 at Lost Dog Creek and relocated downstream of the original gage. The conversion factor for the previous measurements is 8.96 ft. 5.3.1 Lost Dog Creek Lost Dog Creek drains an urbanized area of 0.41 sq mi. with an average slope of 7%. It is composed of three branches which start at Bergis Rd, Luscher Farms and the Lake Oswego Public Golf Course with two branches joining within the first 1,300 ft and the third branch not joining until approximately 500 ft before the mouth. Both primary branches daylight in and out of piped areas that have primarily residential and institutional uses (churches, a golf course, and schools). The stream channel near the gaging station is moderately entrenched with cascading pools, steep banks, and little vegetation in the channel. The streambed near the gaging station is composed primarily of gravel and cobbles with some boulders. Discharge during Water Year 2019 (WY19) ranged from 0.01 cfs to an estimated 30 cfs. Stream temperatures recorded by the EX03 sonde ranged from 2.2°C to 19.3°C while the instream monthly sampling records ranged from 4.9°C to 17.3°C. The upper end of the measurements correlated with very low flows (0.02 cfs) in July and August. While the pH range recorded by the sonde ranged from 6.7 to 8, most of the measurements ranged from 7.4 to 7.8. The range recorded during instream monthly sampling was 7.0 to 7.8. Dissolved oxygen concentrations measured by the EX03 sonde ranged from 3.6mg/I to 13.9 mg/L and those measured by the YSI field meter during instream monthly sampling ranged from 7.3 to 13 mg/L. 5.3.2 Springbrook Creek Springbrook Creek drains an urbanized area of 1.6 sq mi with an average slope of 4.5%. It is a largely unconfined stream composed of approximately 9 branches, 3 of which drain a fair amount of land and likely contribute to most of the tributary flow. It drains an area with a mixture of uses (commercial, institutional, and residential). The stream channel in the area of the gaging station is trapezoidal with steep banks and very little vegetation in the channel. The streambed is composed of fines and gravel with cobbles and boulders on top. Discharge measurements during WY19 ranged from 0.33 cfs to an estimated 77 cfs. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 16 Table 10. Summary of Wet Weather Sampling,FY1920 and FY1213-FY1617 c J J J V i�i › E al f CZ cn r6 J to OCA \ 00 ba U OA d to N J J J w Q v > X - O > m VI bA 00 V E °AE \ '1;5 \ Y 3 H a 3 Q. oa °v. \ E z5 c rn E z z a - > Sao . > Sao N c Sao E E E 332 c a � > E u+ z m v O G m ca ( 0 E H R E iA I IT- y Cn c a Y m etc eri 4-' cF Ili H . m H p iv U fn Q U m Z Z ~ O ~ ~ 1- Reese ~ ~ ~ p a Road FY1920 Maximum 0.87 16.7 88.5 7.9 8.01 <2420 22.9 37.0 20 0.32 0.21 0.270 0.18 0.0121 0.0070 0.0034 0.00040 0.095 0.140 48 164 45 149.0 Geomean 0.35 15.4 64.6 7.4 6.45 64 5.9 1.7 3 0.06 0.03 0.029 0.02 0.0033 0.0017 0.0003 0.00013 0.017 0.039 6 42 21 83.6 Minimum 0.17 14.6 39.9 7.1 4.23 <1 <1.7 0.1 <1 <0.006 <0.005 <0.01 <0.01 0.0005 <0.00027 <0.00000666 0.00003 0.002 0.003 <2 <10 <10 47.6 Historical I Maximum NA 14.4 420.9 7.8 11.90 <2420 19.1 100.7 59 0.98 0.42 0.850 6.63 0.0450 0.0150 0.0140 0.00060 0.291 0.107 550 155 180 506.0 Geomean NA 10.3 62.6 7.3 9.47 347 8.6 23.6 14 0.41 0.18 0.407 0.13 0.0217 0.0074 0.0051 0.00020 0.158 0.062 87 70 69 85.0 Minimum NA 8.4 18.5 6.5 6.90 11 2.5 9.0 4 0.16 0.04 0.206 <0.01 0.0090 0.0030 0.0030 0.00007 0.071 0.036 34 42 21 9.2 South Shore FY1920 Maximum 2.0 14.2 70.2 7.2 10.1 <2420 13.9 20.4 12 0.09 0.23 0.229 0.15 0.0190 0.0116 0.00260 0.00017 0.365 0.211 48.0 65 48 52.9 Geomean 1.2 13.4 42.1 6.7 9.5 1769 11.0 15.5 10 0.08 0.23 0.200 0.09 0.0141 0.0081 0.00190 0.00014 0.155 0.166 33.6 48 42 42.6 Minimum 0.7 12.5 30.7 5.9 7.8 649 8.7 11.8 7 0.06 0.23 0.174 0.05 0.0106 0.0058 0.00140 0.00011 0.066 0.130 17.0 37 37 24.3 Historical I Maximum 1.6 13.1 263.5 7.6 11.60 <2420 30.0 49.0 10 0.15 15.70 0.520 0.13 0.0430 0.0400 0.00200 0.0430 0.185 0.137 60.0 98 52 168.0 Geomean 0.8 10.3 99.9 7.2 10.10 905 24.0 32.5 3 0.05 1.39 0.187 0.05 0.0087 0.0054 0.00088 0.0087 0.044 0.032 20.0 72 32 23.9 Minimum 0.2 7.6 49.8 6.4 9.03 37 19.0 18.4 <1 0.01 0.64 0.080 <0.01 0.0038 0.0020 0.00028 0.0038 0.018 0.010 3.4 41 21 4.4 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 17 Temperatures recorded by the sonde ranged from 3.7°C to 18.8°C while the recorded instream monthly sampling measurements ranged from 6.3°C to 15.1°C. The upper temperature range occurred in July and August when discharges were at the low end of the range. The range for pH recorded by the sonde was 6.4 to 7.4 which correlated well with the instream monthly sampling measurements (6.4 to 7.3). Dissolved oxygen concentrations from the sonde ranged from 7.4 mg/L to 12.9 mg/L whereas the range for the instream monthly sampling measurements was 6.3 mg/L to 12.3 mg/L. The low end for the instream monthly sampling occurred in August and is likely due to low flow. The median dissolved oxygen concentration for the instream monthly sampling was 7.9 mg/L. 5.4 Total Maximum Daily Loading Within the City's MS4 jurisdiction are several streams, monitored and unmonitored, that are affected by Total Maximum Daily Loads (TMDLs). All TMDLs but temperature have a wasteload allocation (WLA) associated with them. For the purposes of this report, the discussion focuses on TMDLs affecting the streams that are part of the City's instream monitoring program in order to provide adequate data for analysis. 5.4.1 Bacteria (E.ColiI Sources of bacteria include animal waste,wastewater system overflows,failing septic systems, and illegal dumping. For the City, bacterial TMDLs have been set for the Willamette River, the Tualatin River watershed (all tributaries and ephemeral streams), and Springbrook Creek (see Table 11). Table 11. Bacterial Wasteload Allocations for Streams in Lake Oswego Affected Lake Oswego Waterbody Streams Parameter Season/Target' Wasteload Allocation Maximum 406 Col/100mL Tualatin River Carter Creek Bacteria Summer Stormwater 12000 Col/100mL (All Streams) Ball Creek (2001) Winter Stormwater 5000 Col/100mL Maximum 406 col/100mL 80%Reduction (1997- Winter Geomean/Median:208/172 2003 Data) Winter Minimum/Maximum: 13/2,419 Springbrook Springbrook Bacteria Summer Geomean/Median: 365/388 Creek Creek (2006) Minimum/Maximum Summer: 34/2,420 Nettle Creek Maximum 406 col/100mL Willamette Lost Dog Creek Bacteria 78%Reduction (All Tributaries) Boones Ferry (2006) (1996-2002 Data) Dependent on Stream 1—Summer=May 1-Oct 31;Winter=Nov Ito Apr 31;2—Summer=Jun Ito Sep 30;Winter/Spring/Fall=Oct 1 to May 31 5.4.1.1 Fanno Creek Tributaries The WLAs for Fanno Creek included three thresholds—a maximum for a single grab sample, a flow-based criteria, and a 30-day log mean criteria. Because the City does not collect samples in the Tualatin watershed specifically during rain events, the bacterial analysis focuses on the 406 colonies/100 ml instead of calculating the WLA based on a rain event. In addition,the 30-day log mean threshold cannot be analyzed because the analytical data for the monthly instream monitoring sites is 1 data point every 30 days. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 19 Monitoring sites affected by the Tualatin River bacteria TMDL are Carter Creek and Ball Creek. While the maximum bacterial concentration for Ball Creek and Carter Creek were both above the 406 col/100mL, the geomean concentrations for both sites were near or below the threshold (see Table 12). Historically, the bacteria geomean concentrations were below the 460 col/100mL threshold (see FY1213-FY1516 concentrations). Table 12. E. Coli Concentrations in Ball Creek and Carter Creek, 1997-2003 vs FY1920 Ball Creek Carter Creek FY1213-FY1516 FY1920 FY1213-FY1516 FY1920 Threshold, Col/100 mL A Col/100 mL Col/100 mL 1 Col/100 mL Winter Maximum 1,733 >2,420 >2,420 649 Winter Geomean 107 247 97 82 Summer Maximum >2,420 >2,420 1,200 461 Summer Geomean 196 485 175 267 5.4.1.2 Springbrook Creek Springbrook was given a specific bacteria TMDL that is based on the data collected by the City from 1997 to 2003 (see Table 13). The TMDL requires a reduction in concentrations of 80%. The winter concentrations saw progress towards the 80% reduction with all but the minimum reduced by more than 40%. The summer concentrations did not show the same reductions. The FY1920 data shows a continued decrease in winter concentrations when comparing the 1997 to 2003 data to the FY1213 to FY1617 data and the FY1920 data. The summer and winter geomean concentrations s are both below the 406 col/mL threshold at 396 and 64 col/100mL, respectively. Table 13. E. Coli Concentrations in Springbrook Creek, 1997-2003 vs FY1920 Change FY1213 to From 1997-2003 Threshold 1997-2003 Data FY1617 FY1920 to FY1920 Summer Maximum 2,420 733 1,771 -27% Summer Median 388 74 342 -12% Summer Geomean 365 78 396 8% Summer Minimum 34 10 147 432% Winter Maximum 2,419 2,076 1,378 -43% Winter Median 172 63 42 -76% Winter Geomean 208 80 64 -69% Winter Minimum 13 8 15 15% • 5.4.1.3 Willamette River Tributaries The remaining monitoring sites fall under the Willamette River bacterial TMDL which requires a 78% reduction in bacterial concentrations. The FY1920 concentrations are not indicative of reaching the 78% reduction in bacterial concentrations, however the geomean concentrations at Lost Dog Creek and at the monitoring site at Boones Ferry were below the 406 col/100mL threshold (see Table 14). City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 20 Table 14. E.Coli Concentrations at Nettle Creek, Lost Dog Creek, and Boones Ferry, 1997-2005 vs FY1920 Nettle Creek Lost Dog Creek Boones Ferry Threshold 1997-2005 FY1920 1997-2005 FY1920 1997-2005 FY1920 Maximum <2,420 <2,420 2,420 1,076 <2,420 345 Median 222 666 120 83 41 36 Geomean 237 606 127 66 34 41 Minimum 21 77 2 4 <1 7 5.4.2 Dissolved Oxygen Dissolved oxygen wasteload allocations were set by the 2001 Tualatin River TMDL. The WLA for Fanno Creek tributaries requires a target concentration of 6.5 mg/L using a surrogate measure of a 50%decrease from pre-1998 concentrations for total suspended solids (TSS) and total volatile suspended solids (VSS). The City has monitoring data starting in 1997 and the analysis provides a comparison between 1997-1998 concentrations and from FY1213 to FY1516 concentrations. Because VSS monitoring wasn't required until 2012,the VSS analysis does not provide a comparison to the 1997-1998 concentrations. Ball Creek and Carter Creek, covered under this WLA, met or were close to attaining the summer target DO concentration of 6.5 mg/L for FY1920 (9.51 mg/L and 5.97 mg/L respectively). They were above historical concentrations (8.71 mg/L and 5.28 mg/L respectively). The summer TSS concentrations in Ball Creek showed a decrease of 61% from historical concentrations and a decrease of 79% when compared to 1997-1998 concentrations (see Table 15). The summer TSS concentrations in Carter Creek showed a decrease of 24% from historical concentrations and a 68% decrease when compared to 1997-1998 concentrations. The VSS concentrations in Ball Creek decreased 19% from historical concentrations. Summer VSS concentrations for Carter Creek in FY1920 showed a decrease of 21%from FY1213-FY1516. Table 15. Dissolved Oxygen,VSS, and TSS Concentrations in Ball Creek and Carter Creek, FY1920 Ball Creek Carter Creek Parameter 1997-1998 Historical FY1920 1997-1998 Historical FY1920 Dissolved Oxygen, (mg/L) NA 8.71 9.51 NA 5.28 5.97 TSS1(mg/L) 8 4.4 1.7 10 4.2 3.2 VSS1(mg/L) NA 37 30 NA 43 34 1—Concentration given is the summer geomean; Historical—FY1213 to FY1516 5.4.3 Chlorophyll a and pH Chlorophyll a and pH TMDLs were set in the 2001 Tualatin River TMDL and revisited, for Oswego Lake, in 2012. Total phosphorous is used as the surrogate measure for pH and chlorophyll a. Oswego Lake has historically drawn from the Tualatin River so the lake and its tributaries were included in the 2001 TMDL5 for chlorophyll a and pH. The practice of drawing water from the Tualatin River has ceased, however legacy concentrations remain in the lake. Affected monitoring sites under the City's City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 21 jurisdiction include Ball Creek, Carter Creek, Springbrook Creek, Lost Dog Creek, and Boones Ferry (see Table 16). Table 16. Chlorophyll a and pH Wasteload Allocations for Streams in Lake Oswego Affected Lake Waterbody Oswego Streams Parameter' Season/Target2 Wasteload Allocation Summer Median Phosphorous 0.13 mg/L Fanno Creek Ball Creek pH/chlorophyll a Summer Max Phosphorous 0.46 mg/L (All Tributaries) Carter Creek (2001) pH Target 6.5-8.5 Tualatin River (All Tributaries Summer Median Phosphorous 0.14 mg/L and Ephemeral pH/chlorophyll a Summer Max Phosphorous 0.49 mg/L Streams) No monitoring sites (2001) pH Target 6.5-8.5 Summer Baseflow Conc 0.09 mg/L Summer Baseflow Load 272 lbs/season Oswego Lake Summer Stormwater Load 139 lbs/Season (All Tributaries Springbrook Creek' Total Winter Baseflow Conc 0.15 mg/L and Ephemeral Lost Dog Creek phosphorous Winter Baseflow Load 986 lbs/Season Streams) Boones Ferry (2001 and 2012) Winter Stormwater Load 858 lbs/Season 1-The surrogate measure for pH and Chlorophyll a is total phosphorous;2-Summer is Jun 1 to Sept 30 except for Springbrook Creek which is May 1 to Oct 31,Winter is Nov Ito Apr 30 5.4.3.1 Fanno Creek Tributaries Summer pH concentrations in Carter Creek remained fairly steady with a maximum of 7.32 and a minimum of 7.08. Ball Creek concentrations also remained fairly steady with a maximum of 7.91 and a minimum of 7.66. Both monitoring sites attained the target pH level of 6.5 to 8.5. The maximum summer phosphorous concentration in 2001 was determined to be 0.46 mg/L with a median of 0.13 mg/L. Both Carter Creek and Ball Creek met these thresholds(see Table 17). Carter Creek and Ball Creek also showed a decrease from historical (FY1213-FY1516) concentrations. Table 17. Phosphorous Concentrations and pH in Ball Creek and Carter Creek, FY1920 Ball Creek Carter Creek Parameter Target FY1213-FY1516 FY1920 FY1213-FY1516 FY1920 pH Range,Summer 6.5 to 8.5 6.0 to 8.1 7.7 to 7.9 7.2 to 7.2 7.1 to 7.3 Total Phosphorous, Summer Maximum (mg/L) 0.46 0.93 0.09 0.42 0.14 Total Phosphorous, Summer Median (mg/L) 0.13 0.12 0.10 0.12 0.10 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 22 5.4.3.2 Oswego Lake Tributaries The maximum summer concentration for total phosphorous in the Oswego Lake tributaries is 0.09 mg/L and the maximum winter concentration is 0.15 mg/L. The pH target is 6.5 to 8.5. All of the monitored sites were within the target pH range throughout the year(see Table 18). The maximum summer concentration in Springbrook Creek was 0.21 mg/L and did not reach the target 0.09 mg/L until the summer median concentration. The maximum winter concentration (0.10) was well below the maximum threshold. The maximum phosphorous concentrations for the winter and summer in Lost Dog Creek were at the thresholds stipulated in the TMDL document but did not exceed them. They were well below the historical maximum summer and winter concentrations, 0.63 mg/L and 1.60 mg/L respectively. Summer concentrations at the Boones Ferry monitoring site were below historical (FY1213 to FY1516) concentrations but exceeded the threshold set in 2012. The winter concentrations, however were below the 2012 threshold and the historical concentrations. Table 18. Phosphorous Concentrations and pH in Selected Oswego Lake Tributaries, FY1920 Springbrook Creek Lost Dog Creek Boones Ferry FY1213- FY1213- FY1213- Parameter Target FY1516 FY1920 FY1516 FY1920 FY1516 FY1920 pH Range 6.5 to 8.5 6.4 to 8.7 6.6 to 7.0 6.8 to 8.6 7.3 to 7.8 6.5 to 8.6 6.5 to 7.8 Total Phosphorous, Summer'(mg/L) 0.09 0.26 0.21 0.63 0.09 0.32 0.12 Total Phosphorous, Winter(mg/L) 0.15 1.85 0.10 1.6 0.15 1.00 0.11 1-Concentration is the seasonal maximum 5.4.4 Biocriteria The threshold for biocriteria is a "sufficient(water)quality to support aquatic species without detrimental changes in the resident biological communities". The waterbodies that have biocriteria TMDLS include Fanno Creek and Tryon Creek. Tributaries to those streams that are within the City's jurisdiction are Ball Creek, Carter Creek, and Nettle Creek. The City conducts regular macro-invertebrate assessments with other co-permittees every 3-4 years which are used to assess the health of biological communities. The most current assessment was completed in 2018. 5.4.4.1 Physical Characteristics Nettle Creek and Ball Creek had the highest percent of riffles (56% and 53%, respectively) whereas the percentage of riffles in Carter Creek was only 8% (see Table 19). Mature forested riparian zones, as indicated by canopy cover,occurred along Ball Creek, Nettle Creek,and Tryon Creek. Carter Creek showed the highest tendency for sediment loads (40%fines) and the highest embeddedness (58%). City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 23 5.4.4.2 Biological Characteristics Both the Multi-Metric Index (MMI) and the Predator Model (Marine Western Coastal Forest) were used to assess the biological communities in Ball Creek, Carter Creek, Nettle Creek, and Tryon Creek. The DEQ MMI uses 10 factors (number of sensitive species, number of pollution-tolerant species, population diversity, etc.) to determine the final score. A score greater than 39 represents pristine conditions while a score below 20 represents severely disturbed communities. The Predator Model compares a list of expected species to the observed species in the sample to determine the percentage of species that should be at the site.A score of 1 means that all of the expected species were present whereas a score of 0.5 means that only half of the expected species were present. Biological conditions were found to be similar to the 2013 conditions. Ball Creek was categorized as severely disturbed while Tryon Creek and Nettle Creek were categorized as moderately disturbed. Biological communities in Ball Creek, Carter Creek, and Tryon Creek showed temperature-related stress. Sediment-induced stress was indicated in Ball Creek and Nettle Creek. Tryon Creek showed a possibility for sediment-induced stress but the data was not conclusive. Mayflies, stoneflies, and caddisflies are widely regarded as the most sensitive to pollution and habitat degradation. Mayfly and caddisfly were found at all four sites while stonefly was only found in Nettle Creek and Tryon Creek. Table 19. Summary of Biological and Physical Characteristics of Selected Streams in Lake Oswego Nettle Parameter Ball Creek Carter Creek Creek Tryon Creek Predator Score 0.39 0.29 0.44 0.39 MMI Score 18 18 20 22 Sediment Stressors Temperature Temperature' Sediment Temperature • Riffle 53 8 56 20 Canopy Cover 97 31 92 87 Riparian Buffer Width,ft 213 75 207 174 99% Coarse 60% Coarse 98% Coarse 99% Coarse Streambed 1% Fines 40% Fines 2% Hardpan 1% Fines • Embeddedness 29 58 30 22 • Eroding Banks 88 21 80 35 1—For streams with low riffle occurrence,a test for sediment stress is not applied 5.5 Water Quality Limited Streams Section 303(d) of the Clean Water Act requires the administrator of the CWA(Oregon DEQ)to determine when a water body can no longer provide its beneficial uses because of impaired water quality. Beneficial uses for the Willamette River and its main tributaries such as the Tualatin River include fishing, drinking water, recreation, industrial water supply irrigation, livestock watering, aquatic life, wildlife, boating, aesthetic quality, and hydropower. The mainstem of the Willamette River also includes commercial navigation and transportation as a beneficial use. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 24 The current 303(d) list is the 2012 assessment which was approved by EPA in 2018. Several new parameters were listed that for waterways within the City's jurisdiction (see Table 20). The following analysis only covers streams and parameters which are part of the City's monitoring network. Table 20. Streams designated as Water-Quality Limited under the Clean Water Act Section 303(d) Stream Stream Affected Name Reach Waterbody in City Parameter Time Period Limit Unnamed Stream 0 to 2 Nettle Creek Biological Criteria' All Year None Specified Tryon Creek 0 to 2.5 Nettle Creek DO' Oct 15—May 15 DO> 11 mg/L Streams on south Ammonia' Tualatin River 0 to 44.7 side of City Zinc' All Year Table 20 Streams on south Tualatin River 0 to 80.7 side of City Biological Criteria All Year None specified Copper' Streams on south Iron' Tualatin River 0 to 80.7 side of City Lead' All Year Table 20 Streams on south Tualatin River 0 to 80.7 side of City Mercury' All Year Table 40 Arsenic',3 Ball Creek Tetrachloroethylene'3 Fanno Creek 0 to 13.9 Carter Creek Thallium13 All Year Table 40 Copper' Dieldrin3 Iron' Ball Creek Lead' Fanno Creek 0 to 13.9 Carter Creek Zinc' All Year Table 20 Ball Creek Fanno Creek 0 to 13.9 Carter Creek Dissolved Oxygen2 Jan 1 to May 15 DO> 11 mg/L Biological Criteria Aldrin3 DDE3 Willamette Streams on east side Dieldrin3 River 0 to 24.8 of City PCBs3 All Year None Specified Willamette Streams on east side Chlordane3 River 0 to 24.8 of City Hexachlorobenzene3 All Year Table 20 Copper' Cyanide3 DDT3 Iron3 Willamette Streams on east side Lead1,3 River 0 to 24.8 of City PAHs3 All Year Table 20 Willamette Streams on east side River 0 to 54.8 of City Chlorophyll a2 Summer None Specified Oswego Creek 0-3 Oswego Creek DO',Z Jun 1—May 15 DO>11 mg/L 1—Added with 2012 303(d)Assessment,2—Surrogate parameter for DO is TSS and VS and for Chlorophyll a is Total Phosphorous; 3—Not regularly monitored City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 25 5.5.1 Biological Criteria The only stream listed in the 303(d)assessment as impaired for dissolved oxygen was an unnamed stream which is likely Nettle Creek. Please see Section 5.4.4 for the analysis of the biological community in Nettle Creek. 5.5.2 Dissolved Oxygen Fanno Creek and Tryon Creek are listed in the 303(d) assessment as impaired for dissolved oxygen. The streams in the City's monitoring network which are tributary to these streams include Ball Creek, Carter Creek, and Nettle Creek. The target concentration for dissolved oxygen is 11 mg/L and higher from Jan 1 to May 15 for Fanno Creek. In FY1920,the measurements of dissolved oxygen in Ball Creek from Jan 1 to May 15 showed a maximum of 12.1 mg/L and a median of 11.0 mg/L. The measurements of dissolved oxygen in Carter Creek showed a maximum of 11.9 mg/L and a median of 10.8 mg/L. The target concentration for dissolved oxygen is 11 mg/L and higher from Oct 15 to May 15 for Tryon Creek. In FY1920, the measurements of dissolved oxygen in Nettle Creek showed a maximum of 13.4 mg/L and a median of 12.2 mg/L. 5.5.3 Metals Zinc, copper,and lead were listed in the 303(d)assessment for Fanno Creek. The streams under the City's jurisdiction which are tributary to Fanno Creek are Ball Creek and Carter Creek. In the 303(d)assessment, copper and zinc were impaired for human health and aquatic life whereas lead was only impaired for aquatic life. The metals criteria for aquatic life is based on a formula involving hardness for zinc and lead. The criteria for copper uses modeling software (the Biotic Ligand Model) and several parameters such as anions, cations, and carbon. As shown in Table 21,zinc and lead concentrations in Ball Creek and Carter Creek are below the thresholds specified by the DEQ Aquatic Life Criteria. The DEQ Human Health Criteria for zinc is 2,100 µg/L and for copper is 1,300 kg/L. The median zinc concentrations,as shown in Table 21 is below this threshold. The median dissolved copper concentrations in Ball Creek and Carter Creek were 2.7 µg/L and 1.6 µg/L, respectively. Table 21. Zinc and Lead Concentrations and Thresholds for Ball Creek and Carter Creek, FY1920 Median FY1920 Median Hardness, Concentration, Stream Parameter (mg/L) Threshold, µg/L µg/L Acute: 77.2 Ball Creek Zinc, Dissolved 61.1 Chronic: 77.8 16 Acute: 110.5 Carter Creek Zinc, Dissolved 93.3 Chronic: 111.4 7 Acute: 37.6 Ball Creek Lead, Dissolved 61.1 Chronic: 1.5 0.05 Acute: 59.9 Carter Creek Lead, Dissolved 93.3 Chronic: 2.3 0.03 City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 26 6 ADAPTIVE MANAGEMENT Adaptive management is required as part of the MS4 permit and is defined in the permit as a method for refining and improving stormwater programs. Adding, reducing, replacing, or eliminating any best management practice is considered a permit revision and must undergo review and approval by DEQ. The City proposes no changes to its SWMP or BMP requirements. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 27 This page intentionally left blank City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 28 APPENDIX A 2012 SWMP IMPLEMENTATION STATUS City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 29 This page intentionally left blank City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 30 Table A.1. Stormwater Management Plan Metrics, FY1819 Progress Key to BMP Parameter Symbols: A full circle (•) indicates the BMP is expected to address the parameter.An empty circle (0) indicates the BMP may be expected to address the parameter. A blank cell indicates that the effect of the BMP is uncategorized. E.Coli—Escherichia Coli bacteria; P—Total phosphorous; Hg—Mercury; SVS—Total Settleable Volatile Solids; Eng—Engineering; PW—Public Works; Fire—LO Fire Dept; Plan—Planning; Parks—Parks and Recreation Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 The three priority outfalls were inspected in FY1920. Two 1)Conduct dry weather field 1)Track the number and of the outfalls have flow each year, however field screening at 100%of priority percent of priority outfalls outfalls within the City inspected annually. measurements taken at the sites were not indicative of annually. Based on results of illicit discharges. The third outfall had flow which was BMP ILL1- tested for field measurements and E. Coli. The results Im lement annual inspections and any 2) Describe results of all p citizen reports,conduct follow up investigations were indicative of groundwater and not an illicit the Illicit discharge. Discharge 0 0 0 Eng follow-up investigations and conducted. Elimination take enforcement actions. Program Additional Commitment: Develop an IDDE Enforcement Response Plan by November 1,2012. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 31 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1) Respond to all spills 1) Indicate the number of Five spills were reported to DEQ in FY1920;four were SSOs reported to the City using spills reported annually. and 1 was a fuel spill. The fuel spill did not reach the BMP ILL2- general procedures outlined stormwater system but exceeded the threshold volume for Implement under BMP ILL2. 2)Track the number of a land-only spill (>42 gallons). the Spill O O O PW spills responded to by the Fire City. Staff responded to 23 spills. Staff from the Fire Department Response Program 3) Describe activities and Public Works teamed up to provide spill management conducted as a result of for the one spill that entered the stormwater system. each spill BMP ILL3- 1) Ensure all identified cross 1) Indicate the number of There were no cross connections discovered. Control connections are abated upon cross connections Infiltration discovery. discovered and abated and Cross O O PW annually. •Connections to the Stormwater System City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 32 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1) Annually review and 1)Track the number of No notification letters were sent to businesses in regard update the list of industrial potential high pollutant to contacting DEQ to determine if a DEQ 1200-Z permit is BMP IND1- dischargers and potential high source facilities identified required for their facility. In January 2020, in response to a Screen pollutant source facilities to annually. phone call, a facility(SIC Code 3841-Surgical and Medical the City's MS4 system. Instruments and Apparatus)was requested to contact Existing and 0 0 0 Engy y 2)Track the number of DEQ's 1200-Z program to determine if they needed a New 2) Notify the industrial facility industrial facilities permit. A follow-up phone call was made to the DEQ Industrial and DEQ when facilities are requiring permits 1200-Z Program Manager to let them know to expect an Facilities identified that are subject to identified annually. inquiry/application. an industrial stormwater permit. 1) Develop a strategy for high 1)Track the number and The strategy for inspecting high pollutant-source facilities BMP IND2- pollutant source facility results of potential high was completed in June 2014; using a combination of Conduct inspections and follow up by pollutant source facility business licenses,SIC codes, DEQ permit searches,and Inspections of July 1,2013. inspections. business types. High 0 0 0 Eng Pollutant 2) Inspect the identified, No inspections were performed during the reporting Source potential high pollutant period. Facilities source facilities a minimum of once over the permit term. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 33 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1) Implement ESC program by 1) Record the number There were 155 ESC permits issued in FY1920. issuing permits. of City ESC permits There were no updates to the ESC Manual,wet weather 2) Provide wet weather issued annually. requirements, nor the Stormwater Management Manual. BMP EC1- construction requirements Implement with all City ESC permits. the Erosion Additional Commitment: and Sediment O Eng Document updates to the Control(ESC) Clackamas County ESC Manual and Planning and Design Manual Municipal and the City's Design and Code Construction Standards for Sanitary Sewer and Surface Water Management,as necessary. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 34 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coll P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1)Conduct an initial and final 1)Track the number of In FY1920, there were 84 first inspections, 76 interim site inspection for all initial and final ESC inspections, and 25 final inspections. Thirty permits construction sites requiring an inspections conducted required more than 3 inspections. Four citations were ESC permit. issued in FY1920. 2)Track the number of 2)Conduct at least one unscheduled inspections. unscheduled inspection BMP EC2- during active construction at 3)Track the number of all sites requiring a CityESC sites with more than 3 Conduct ESCq g inspections. Inspections 0 • • Eng permit, and conduct and additional inspections for 4)Track the number of Enforcement problematic sites. enforcement actions 3) In conjunction with including written construction activities warnings. requiring a City-issued ESC permit, implement an escalating enforcement matrix. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 35 Provide educational materials 1)Summarize the To leverage public education,outreach,and involvement two times per year related to distribution and content of efforts,the City is a member of the Regional Coalition for impacts of fertilizers, outreach material related Clean Rivers and Streams(RCCRS),Clean Rivers and herbicides,and pesticides on to landscape management Streams(CRS), KPTV's Clean Water Partners,Tualatin water quality and on the use on an annual basis. Basin Public Awareness Committee (TBPAC),and the of alternative, Regional Water Providers Consortium (RWPC). The environmentally-friendly 2)Summarize the RCCRS, KPTV,and RWPC support media-based education products. distribution and content of while TBPAC focuses on hands-on outreach efforts. The 2) Provide educational outreach material related CRS is focused on state-wide messaging and is still in the materials related to to proper disposal formative stages. watershed protection, proper practices for oil, hazardous The RCCRS staffed a booth with local watershed councils disposal practices, and waste, paints, etc.,on an at the Big Float to engage approximately 500 people in facilitation of public reporting annual basis. salmon-friendly practices and watershed information. of illicit discharges annually. 3)Track the number and They also sponsored a video contest across the metro BMP PE1- area for high school and middle school students. The Provide 3)Conduct catchbasin percent of total marking during the permit catchbasins marked video entries covered hazardous waste disposal practices, Public Eng term. annually. pet waste disposal, pesticide and fertilizer use,waste oil Education 0 0 0 PW disposal, littering,and Leave No Trace. Entries from 36 and Outreach Public 4) Continue participation teams were received which were put on the RCCRS' Materials Affairs with the Regional Coalition of 4) Report on the status of YouTube page where they reached more than 4,000 Regarding Clean Rivers and Streams. the public education g g effectiveness evaluation. people. The group has a website and is active in social Stormwater media with one post per week on average for Facebook, 5) Coordinate with other local, Phase I permittees in one tweet per week on Twitter,and an Instagram post on the public education average every other week. Facebook ads bought and effectiveness evaluation. promoted by the RCCRS include information on tire recycling,algal blooms,car washing, pesticide effects on 6) Additional Commitment: rivers, and others. The ads reached over 200K people Document other public with more than 190K people engaging(liking, education and outreach commenting,or click-thrus)after seeing the ad. activities not specified as a measurable goal.1) As part of the KPTV regional group,citizens were educated about minimizing fertilizer and pesticide use;car washing practices, keeping stormdrains clear,and sweeping surfaces instead of using pressure sprayers. In all 713 public service announcements were seen by 13.5 million views. On the KPTV website,there were 5,337 page views on the KPTV website and 16,262 videos City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 36 viewed on KPTV's Facebook page. Overall,the campaign reached 16.6 million viewers. Normally, staff provide landscaping/water conservation audits from May to October however, in March 2020, the program was suspended due to COVID-19 concerns. Even with the suspension, staff were able to successfully complete 18 audits including 1 audit for a large multi-family residential commercial property from July to October of 2019. The audits include conversations about responsible water management and the impacts of overwatering, improper plant selection, and excessive fertilizer use on creeks,streams and wetlands. To compensate for the reduced public activities,staff have increased efforts to educate the public via the Water Conservation Program's website and in social media efforts especially the"Nextdoor"social media platform. The City offers free hose timers, rain sensors,soil test kits, and soil moisture probes as well as several brochures providing information on natural gardening, hazards in the home, and safe disposal of household chemicals and medicines.All items and brochures are accessible to the public by requesting them through telephone,email,or website requests. A public event was held to provide information for the Wembley Park Rd project in November 2019 and an event was held for the 10th Street Water Improvement project in January 2020. No projects included public input into the design of CIP projects. In FY1920,23 markers were placed throughout the City. The City provides$38,000 to the regional Backyard Habitat Certification program. The City normally provides free workshops on urban forestry—tree health,canopy effects on stream City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 37 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 temperature, etc.With the COVID-19 restrictions, however,the workshops were cancelled. 1) Continue to provide access 1) N/A City staff provides one-on-one education at the initial BMP PE2— to the Erosion Prevention and inspection in response to questions by contractors. Provide Sediment Control Planning Erosion and Design Manual to Several developers and landscape contractors were Education to 0 0 0 Eng engineers,contractors,and alerted to the Clean Water Services class on maintaining vegetated stormwater facilities. They and others were Construction developers. Site also told of the online version of the class after COVID-19 Operators restrictions went into effect. Several people indicated that they were interested or had signed up for the class. 1) During the permit term, 1) Report on the number In FY1920,75 staff and contractors maintained their ODA require training and of staff attending licenses. certification in accordance continuing education with Oregon Department of classes to maintain ODA Agriculture regulations. applicator license. BMP PE3- Require staff to maintain Conduct Staff certification. Training for 0 0 0 Parks Pest 2) In accordance with the Management update of the City's IPM Practices(see BMP PEST2), annually train staff on new maintenance activities, once revised IPM procedures have been adopted. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 38 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 BMP PE4- 1) Provide spill response 1) Track the number of 50 Fire Department Staff and 25 Public Works staff were Conduct Staff training to appropriate city employees receiving spill trained in spill response, stormdrain blocking, spill and Training in 0 0 0 PW staff annually. training annually. hazardous material mitigation, and incident command Spill (NIMs). Response 1)Conduct 2-4 meetings 1)Track the number of Three staff attended a webinar on stormwater annually for employees employees attending management which focused on regulations, public associated with stormwater meetings regarding education,and maintenance. One staff attended the management within the City. stormwater management national APWA Conference in Seattle with tracks in flood 2)Coordinate annually with annually. reduction,climate resilience, public outreach for green other Clackamas County co 2)Track the number of streets,greenways,stormwater re-use and testing of regarding regional infiltration facilities. One staff attended a floodplain permitteesg g g' joint projects related to managers conference and the Oregon APWA conference water quality efforts. stormwater management BMP PE5- in which the City is where they were given an award for the D Avenue Promote Staff 3)Throughout the permit currently involved. project. Two people recertified their CESCL. Education 0 0 0 Eng term, participate,where and practicable, in conferences Participation and training opportunities available through state and local agencies. 4)Additional Commitment: Continue to attend and participate in conferences, meetings,and seminars related to stormwater and surface water quality. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 39 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1)Continue to review all new 1)Track the number of There were 26 land-use applications reviewed for BMP DEV1— development applications for new development stormwater requirements. Development • • • Eng compliance with existing applications reviewed for Review standards for water quality. stormwater quality compliance. 1) During permit year 1, (1) N/A There were no changes to the SWMM for FY1920; review current municipal code however an update was initiated that will be completed in provisions for consistency FY2021. Engineering design standards were adopted in with NPDES MS4 permit June 2020, however they focused on conveyance design BMP DEV2- language. Review the City's instead of stormwater facility criteria and design. There Review and Surface Water Technical were no changes to the stormwater municipal code in Update the Handbook and other local FY1920. Municipal jurisdiction's stormwater Code and • • • Eng design manuals and develop a Development manual consistent with Standards NPDES MS4 permit language. Related to Stormwater 3) Update the City's existing post-construction stormwater design standards and code language by November 1, 2014. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 40 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coll P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 •Annually sweep all curbed 1) List all curbed arterial The sweeping dates are maintained in the City's asset arterial streets between 13 streets and dates swept. management system which is available for review. There BMP OM1— and 22 times. were 5,224.7 miles of streets swept with 1,906.5 cu yd Street O O • PW 2) List all curbed •Annually sweep all curbed residential streets and Sweeping collected as debris. residential streets between 2 dates swept. and 6 times. 1) Pick up all deicing materials 1) Report the volume of Public Works reported that 1,465.1 cu yd of leaves were as promptly as weather and leaves collected from city removed from the City's streets. The City resources allow. streets in the annual Every year,the City provides dropboxes for leaf collection. 2) Pick up all leaf debris from report. No one took advantage of the offer in FY1920. Through BMP OM2— city streets a minimum of the City's regional partnership for PSAs with KPTV,the 2) Provide the description Deicing and 0 0 • PW once per season to prevent of leaf collection public was educated on proper leaf disposal and the Leaf inlet clogging and localized information that is removal of leaves from catchbasins to prevent flooding. Collection flooding. distributed to the public 3) Promote yard waste for leaf pick up and collection services provided recycling. by City Waste Contractor once per year City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 41 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1) Inventory facilities subject 1)Track the status of The City has no formal strategy to minimize stormwater to this permit requirement inventorying and from City-owned buildings or properties other than to and implement and track implementing strategies at follow the requirements of the SWMM. BMP 0M4- strategies to reduce the facilities subject to this Reduce the impact of stormwater runoff requirement. The Marylhurst Pump Station and 10th St Water Impact of from these facilities by July 1, Improvement CIP projects reduce the stormwater volume Stormwater 0 0 0 PW 2013. leaving their respective sites. The Marylhurst Pump Runoff from Station was upgraded and includes pervious pavers and Municipal sheetflow to landscaped areas to reduce the stormwater Facilities discharging from the site. The 10th St Water Improvement project converted a reservoir to a water pump station; it includes vegetated stormwater facilities and has a smaller footprint than the original reservoir. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 42 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 1) Inspect the public 1)Track the number and Public Works reported that 195 manholes were inspected stormwater conveyance length of conveyance and cleaned. Staff inspected 475 ft of stormline and BMP 0M5— system components(pipes, system components cleaned 1,500 ft of stormline. Inspection culverts,ditches, and inlets) inspected annually. In FY1920, PW staff repaired 2,080 ft of ditches. In and during the permit term. 2) Describe all addition,staff keep a list of the most problematic ditch Maintenance • 0 • PW 2) Based on the results of maintenance activities inlets;92 were inspected and cleaned 15 times in FY1920 of Public inspections and citizen potentially impacting and 83 were inspected and cleaned 16 times. Conveyance complaints, maintain/repair water quality that are System the conveyance system conducted annually. Public Works estimated that 3,000 gallons of an anti-icer Components components in need of containing magnesium chloride was used in FY1920. service during the permit term. 1) Inspect all public sumped 1)Track the number and There were 1,144 catchbasins cleaned in FY1920. There .BMP 0M6— catchbasins. percent of catchbasins were 46 new catchbasins installed Inspection inspected annually. and 2) Maintain a minimum of 2)Track the number and Maintenance • 0 • PW 90%of the city owned percent of catchbasins of Public sumped catchbasins annually, maintained annually. Sumped based on regular maintenance catchbasins schedules and results of inspections. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 43 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 • • Develop a program to track 1)Track the status of the Staff created the procedure for inspecting and maintaining and report on public and program to track public private stormwater facilities in FY1920. The City Council private stormwater facility and private stormwater was briefed about the program in December 2019, maintenance activities by July facility operation and however COVID-19 precautions delayed the private 1,2013. maintenance. stormwater facility inspections using the new protocol until • Inspect all public 2)Track the number and June 2020. There is no official procedure for inspecting and stormwater facilities. percent of public maintaining public stormwater facilities. • Conduct routine stormwater facilities The following public stormwater facilities were inspected BMP 0M7— maintenance activities to inspected. and maintained in FY1920: Tracking, ensure functionality of public 3)Track the number of 3 filter vaults Maintenance, PW stormwater facilities. public stormwater 24 stormwater planters and • • • En • Maintain an inventory of facilities maintained and 5 detention ponds Inspection of g private stormwater facilities. provide a description of 13 other stormwater facilities. stormwater •Annually inspect 10%of maintenance activities. Facilities private water quality facilities 4)Track the number and Nine properties had their stormwater facilities inspected in FY1920. Seven properties finished construction in 2018 for which an O&M agreement percent of private is on file with the City. stormwater facilities and one each finished construction in 2017 and 2019. inspected. Document the Overall, UlCs(infiltration galleries, infiltration trenches, and drywells)constituted the majority of the inspected date of inspection. facilities as well as the amount of impervious area treated by the facilities. Two properties only required one inspection. None required three inspections and none received citations. City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 44 Does the BMP Address: Best Management Hg Practice or E. or Resp Measurable Goals Tracking Measures Activity Coli P SVS Dept (2012 SWMP) (2012 SWMP) Tracking Measure Status,FY1920 The City applied 215 gallons and 296 pounds of pesticides 1)Continually ensure that 1) Following development in FY1920. The active ingredient in most of the products 100%of pesticide applicators of a process for was triclopyr,glyphosate,trifluralin,and BMP PEST1— operating within the public inventorying pesticides, Reduce right-of-way are certified and annually report on the pentachloronitrobenzene. Pollutants in licensed. quantity of pesticides To minimize pesticide use,the City's Park Department has Discharges applied to City property. improved the timing on weed removal and increased the associated PW 2) By November 1,2012, use of manual removal in landscaped areas to reduce 0 • 0 with Parks develop a process to 2)Annually report any inventorypesticide use. They also add mulch to bare areas. Public Pesticide, pesticides applied efforts and alternatives to Works has been actively reducing the amount of post- Herbicide, to co-permittee owned or reduce the quantity of emergence herbicide used in the city through the use of and Fertilizer operated property. Upon pesticides used by the City development of the process, on City property. Applications mulch and manual removal. annually inventory pesticide use on applicable property. BMP PEST2— 1)Continue to implement and 1) N/A The City reviewed the March 6, 2013 Integrated Pest Update the by November 1,2014, update Management Practices guidance document. No changes City PW the City of Lake Oswego were made during the reporting year. Integrated 0 • 0 Parks Integrated Pest Management Pest Plan as necessary Management Plan City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 45 APPENDIX B LAKE OSWEGO MONITORING DATA Abbreviations BOD5 5-Day Biological Oxygen Demand Ca Calcium CL2 Chloride Cu Copper DOC Dissolved Organic Carbon Mg Magnesium K Potassium Na Sodium NH3 Ammonia NO3 Nitrate P Phosphorous Pb Lead PO4 Orthophosphate SO4 Sulfate TDS Total Dissolved Solids TOC Total Organic Carbon TSS Total Suspended Solids TVS Total Volatile Solids Zn Zinc City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 46 This page intentionally left blank City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 47 Table B.1 Nettle Creek at Tryon Creek, Instream Monitoring Results, FY1920 Water Specific E.coli Alkalinity Hardness, NH3, NO3, PO4,as Total Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na SO4 BOD5 as N as N Total P P Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSSNN TDS TVS Turbidity TOC DOC Date Time Q(cfs) (°C) (mg/L) (RS/cm) pH 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) (mg/L) (mg/L) 07/16/19 9:40 0.2 16.6 9.00 180.7 7.78 291 - 63.0 - - - - - - <2 0.01 0.53 0.079 0.06 0.0019i 0.0010' 0.0001' <0.000091 0.0047 0.0027 2.5 123 33 5.00 - - 08/22/19 8:25 0.2 15.1 7.51 191.7 7.73 921 - 68.5 - - - - - - <2 0.02 0.37 0.122 0.08 0.0023 0.0012' 0.0002' 0.00004' 0.1160 0.0840 5.0 129 28 7.97 - - 09/19/19 8:50 0.6 14.5 9.85 143.6 7.57 >2420 35.6 43.8 8.4 11.7 3.5 2.1 7.3 14.0 <2 0.03 1.21 0.091 0.06 0.0028 0.0020 0.0004' 0.00004' 0.0067 0.0031 2.0 117 33 9.54 4.51 4.45 10/22/19 8:35 1.9 13.0 10.22 118.1 7.43 2420 - 38.4 - - - - - - 3 0.01 0.34 0.176 0.09 0.0042 0.0022 0.0007 0.00008' 0.0174 0.0068 17.5 96 30 22.40 - - 11/12/19 9:55 0.2 8.1 11.50 187.1 7.12 1553 - 69.7 - - - - - - <2 0.05 0.25 0.081 0.04 0.0016' 0.0008' 0.0003' 0.00002 0.0414 0.0356 15.0 132 29 7.34 - - 12/10/19 8:00 0.5 6.8 12.44 166.1 7.38 77 51.4 57.1 9.7 14.8 4.9 1.8 9.0 12.6 <2 0.02 0.85 0.050 0.03 0.0096 0.0012' 0.0002' 0.00004' 0.0123 0.0070 <2 128 23 3.76 2.51 2.46 01/16/20 9:45 4.3 6.5 13.24 111.5 7.56 411 - 38.0 - - - - - - <2 0.03 0.83 0.104 0.05 0.0028 0.0012' 0.0006 0.00012' 0.0194 0.0097 8.5 99 35 23.90 - - 02/10/20 10:18 0.5 7.0 12.59 143.9 7.74 411 46.6 51.3 8.9 13.3 4.4 1.2 8.5 11.1 <2 0.03 1.25 0.063 0.03 0.0011i<0.00027 0.0001 0.00003' 0.0099 0.0063 4.0 111 19 4.53 1.98 1.82 03/17/20 8:50 0.6 5.0 12.82 149.3 7.70 79 - 56.3 - - - - - - 9 <0.006 1.18 0.038 0.03 0.0012i 0.0007 0.0002' 0.00003 0.0066 0.0037 <1 122 29 5.01 - - 04/09/20 9:07 0.3 8.4 11.61 169.9 7.74 980 - 59.6 - - - - - - <2 <0.006 1.02 0.043 0.03 0.0007'<0.00027 0.0001' <0.000016 0.0054 0.0037 2.5 119 30 3.17 - - 05/14/20 8:40 0.3 11.5 10.42 149.3 7.80 >2420 60.7 59.1 8.1 15.1 5.2 1.8 8.5 8.6 2 0.01 0.61 0.084 0.04 0.0011i 0.0012' 0.0001' 0.00005' 0.0051 0.0038 <1 123 33 7.27 3.09 3.66 06/16/20 9:10 1.0 12.6 10.57 114.2 7.79 411 - 42.1 - - - - - - <2 0.02 0.54 0.094 0.04 0.0023 0.0018' 0.0004' 0.00005' 0.0127 0.0031 7.5 101 22 12.20 - - Maximum 10:18 4.3 16.6 13.24 191.7 7.80 >2420 60.7 69.7 9.7 15.1 5.20 2.11 9.0 14.0 9 0.05 1.25 0.1760 0.09 0.0096 0.0022 0.0007 0.00012 0.1160 0.0840 17.5 132 35 23.90 4.51 4.45 Median 8:58 0.5 10.0 11.04 149.3 7.72 666 49.0 56.7 8.7 14.1 4.65 1.80 8.5 11.9 <2 0.02 0.72 0.0825 0.04 0.0021 0.0012' 0.0002 <0.00009 0.0111 0.0051 3.3 121 30 7.31 2.80 3.06 Minimum 8:00 0.2 5.0 7.51 111.5 7.12 77 35.6 38.0 8.1 11.7 3.54 1.20 7.3 8.6 <2 <0.006 0.25 0.0380 0.03 0.0007'<0.00027 0.0001 <0.00009 0.0047 0.0027 <1 96 19 3.17 1.98 1.82 Summer Seasonal' 9:00 0.4 14.8 9.43 162.2 7.76 666 35.6 53.4 8.4 11.7 3.54 2.11 7.3 14.0 <2 0.02 0.54 0.0925 0.06 0.0023 0.0015' 0.0003' <0.00009 0.0097 0.0031 3.8 120 31 8.76 4.51 4.45 Winter Seasonal' 8:58 0.5 7.6 12.03 149.3 7.63 696 51.4 56.7 8.9 14.8 4.90 1.80 8.5 11.1 <2 0.02 0.84 0.0720 0.04 0.0014i 0.0010' 0.0002' <0.00009 0.0111 0.0066 3.3 121 30 6.14 2.51 2.46 FY1213 to FY1516 Maximum 12:25 ND 16.9 16.21 230.0 8.62 >2420 79.0 84.1 8.6 19.0 6.40 2.10 10.0 14.0 3 1.50 1.70 1.3300 0.25 0.0390 0.0093 0.0210 0.00053 0.2120 0.0400 848.0 160 110 685.00 4.45 4.30 Median 9:44 ND 12.1 10.24 148.9 7.74 150 48.5 56.0 7.6 15.0 4.80 1.80 9.2 9.4 <2 0.10 1.00 0.1100 0.06 0.0011' 0.0010' 0.0005 0.00024 0.0070 0.0050 4.4 120 37 5.89 3.60 3.60 Minimum 8:08 ND 2.8 4.70 48.1 6.41 11 2.2 39.0 1.4 11.1 3.15 1.60 2.3 3.4 <2 <0.001 0.31 0.0100 0.04 0.0007' 0.0007' <0.00006<0.000006 0.0036 0.0024 1.0 49 5 1.14 2.42 2.22 Summer Seasonal' 9:46 ND 15.2 8.84 174.1 7.74 138 67.5 64.0 7.8 16.5 5.44 1.80 9.3 6.1 <2 0.03 0.67 0.1100 0.08 0.0010' 0.0010' 0.0004 0.00013 0.0050 0.0050 12.0 140 36 5.12 3.50 3.60 Winter Seasonal' 9:40 ND 9.2 11.00 142.3 7.74 168 45.0 54.0 6.9 13.7 4.15 1.81 7.5 11.6 <2 0.10 1.10 0.1110 0.05 0.0012i 0.0010' 0.0005 0.00037 0.0105 0.0050 3.5 110 37 6.51 4.01 3.62 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit); NA-Not Applicable; ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 48 Table B.2 Lost Dog Creek at Lake Front Rd, Instream Monitoring Results, FY1920 Staff Water Specific E.coli Alkalinity Hardness, NH3,as NO3, PO4, Gauge, Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na SO4 BOD5 N as N Total P as P Total Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSS" TDS TVS Turbidity TOC DOC Date Time Q(cfs) ft (°C) (mg/L) (µS/cm) pH 100mL) (mg/L) (mg/L) (mg/L)(mg/L)(mg/L)(mg/L)(mg/L)(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)(mg/L) (NTU) (mg/L)(mg/L) 07/16/19 9:40 0.2 0.10 17.3 9.4 118.2 7.74 67 - 36.6 - - - - - - <2 <0.0012 0.34 0.076 0.08 0.0024 0.0016' 0.0001' <0.000091 0.012 0.007 3.0 80 18 5.52 - - 08/22/19 9:15 0.2 0.10 16.3 9.0 117.2 7.70 276 - 39.3 - - - - - - <2 0.02 0.34 0.090 0.09 0.0025 0.0017' 0.0001' <0.000022 0.011 0.011 <2 80 20 0.87 - - 09/19/19 9:40 0.7 0.30 15.1 9.6 96.6 7.57 99 29.0 33.2 4.4 9.2 2.5 1.7 4.5 7.5 <2 0.03 0.51 0.068 0.05 0.0035 0.0026 0.0003' 0.00004' 0.012 0.009 <2 78 22 7.15 3.25 3.32 10/22/19 8:35 1.7 0.40 13.4 10.2 85.1 7.51 1076 - 28.5 - - - - - - 3 0.01 0.26 0.108 0.08 0.0048 0.0032 0.0003' 0.00007' 0.027 0.016 4.5 78 26 10.70 - - 11/12/19 10:30 0.8 9.30 9.0 11.5 98.8 7.31 33 - 35.5 - - - - - - 2 0.02 0.12 0.151 0.07 0.0051 0.0016 0.0012 0.00004 0.038 0.009 22.5 80 25 21.20 - - 12/10/19 8:50 0.5 9.20 7.4 12.3 110.7 7.44 10 35.5H1 37.8 5.0 10.2 3.0 1.3 5.7 8.5 <2 0.02 0.56 0.046 0.03 0.0054 0.0012' 0.0001i 0.00004' 0.027 0.021 2.0 87 24 4.73 1.72 1.93 01/16/20 10:30 3.9 9.38 6.8 13.0 86.6 7.57 152 - 29.9 - - - - - - <2 0.02 0.80 0.056 0.03 0.0022 0.0010' 0.0003 0.00008' 0.027 0.019 5.0 76 37 12.20 - - 02/10/20 10:50 0.8 9.26 7.3 12.5 102.1 7.68 101 32.4 35.5 4.7 9.6 2.8 0.8 5.2 8.4 <2 0.02 0.99 0.027 0.02 0.0013 <0.00027 0.0001 0.00004' 0.011 0.008 <1 86 11 3.72 1.64 2.06 03/17/20 9:40 1.5 9.25 6.2 12.5 98.8 7.70 43 - 40.5 - - - - - - 12 0.02 0.89 0.025 0.02 0.0016 0.0008 0.0002' 0.00003 0.026 0.015 <1 84 26 4.59 - - 04/09/20 9:55 0.5 9.24 9.5 10.4 115.2 7.73 4 - 37.3 - - - - - - 2 <0.006 0.65 0.027 0.02 0.0034 0.0028 <0.00009 <0.000016 0.017 0.013 <1 83 20 2.47 - - 05/14/20 9:35 0.3 9.22 12.2 10.5 97.5 7.70 23 40.2 38.3 4.0 10.4 3.0 1.3 5.3 6.6 2 <0.006 0.27 0.054 0.03 0.0020 0.0020 0.0001' 0.00004' 0.021 0.016 <1 73 19 4.83 2.86 3.25 06/16/20 9:55 1.9 9.26 13.1 10.3 94.7 7.76 160 - 32.9 - - - - - - 2 0.03 0.42 0.058 0.03 0.0029 0.0025 0.0002' 0.00006' 0.022 0.012 <2 73 20 6.77 - - Maximum 10:50 3.9 9.4 17.3 13.0 118.2 7.76 1076 40.2 40.5 5.0 10.4 3.0 1.7 5.7 8.5 12 0.0300 0.99 0.151 0.09 0.0054 0.0032 0.0012 0.00008 0.038 0.021 22.5 87 37 21.20 3.25 3.32 Median 9:40 0.8 9.3 10.9 10.5 98.8 7.69 83 34.0 36.1 4.6 9.9 2.9 1.3 5.3 8.0 <2 0.0200 0.47 0.057 0.03 0.0027 0.0017 0.0001 0.00004 0.022 0.013 <2 80 21 5.18 2.29 2.66 Minimum 8:35 0.2 9.1 6.2 9.0 85.1 7.31 4 29.0 28.5 4.0 9.2 2.5 0.8 4.5 6.6 <2 <0.0012 0.12 0.025 0.02 0.0013 <0.00027 <0.00009 <0.000016 0.011 0.007 <1 73 11 0.87 1.64 1.93 Summer Seasonal' 9:40 0.5 9.2 15.7 9.5 106.9 7.72 130 29.0 34.9 4.4 9.2 2.5 1.7 4.5 7.5 <2 0.0250 0.38 0.072 0.07 0.0027 0.0021 0.0002 0.00004 0.012 0.010 <1 79 20 6.15 3.25 3.32 Winter Seasonal' 9:47 0.8 9.3 8.2 11.9 98.8 7.63 38 35.5 36.4 4.7 10.2 3.0 1.3 5.3 8.4 2 0.0200 0.61 0.050 0.03 0.0028 0.0014 0.0001 0.00004 0.026 0.016 <1 82 25 4.78 1.72 2.06 FY1213 to FY1516 Maximum 14:24 ND ND 20.6 16.2 189.4 8.57 1203 89.0 100.0 7.8 16.0 4.6 1.9 8.8 12.0 3 0.6600 2.30 1.600 0.31 0.0330 0.0074 0.0015 0.00150 0.176 0.170 48.0 180 54 89.20 4.10 4.40 Median 11:31 ND ND 13.4 9.8 123.5 7.74 64 40.0 48.0 6.1 14.9 4.2 1.5 6.9 7.1 <2 0.0250 0.86 0.084 0.05 0.0021 0.0020 0.0005 0.00050 0.014 0.012 2.0 95 30 2.59 3.06 3.03 Minimum 9:36 ND ND 3.3 4.4 49.8 6.79 1 13.4 23.8 2.3 6.7 1.7 1.2 4.1 4.9 <2 0.006 0.03 0.025 0.01 0.0009 0.0008 <0.00009 <0.000009 0.005 0.005 <2 62 5 0.91 2.20 2.00 Summer Seasonal' 11:33 ND ND 16.6 7.2 140.1 7.57 49 52.0 55.0 7.4 16.0 4.6 1.7 7.3 7.1 <2 0.0250 0.49 0.100 0.07 0.0023 0.0023 0.0005 0.00050 0.012 0.012 2.0 107 27 1.54 2.85 2.85 Winter Seasonal' 11:32 ND ND 9.8 10.8 115.4 7.78 87 36.0 44.0 4.9 11.0 2.9 1.3 6.5 6.0 <2 0.0250 1.15 0.061 0.05 0.0017 0.0010 0.0005 0.00035 0.016 0.012 2.0 91 31 4.17 3.39 3.68 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit);NA-Not Applicable;ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 49 Table B.3 Springbrook Creek at Iron Mountain Blvd,Instream Monitoring Results, FY1920 Staff Water Specific E.coli Alkalinity Hardness, NH3,as NO3,as PO4,as Q Gauge, Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na SO4 BOD5 N N Total P P Total Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn 'ISSN" TDS TVS Turbidity TOC DOC Date Time (cfs) ft (CC) (mg/L) (NS/cm) pH 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) (mg/L) (mg/L) 07/16/19 10:50 1.6 0.96 15.1 7.5 168.8 6.66 1120 - 53.4 - - - - - - <2 0.01 0.92 0.091 0.09 0.0016' 0.0010' 0.00006' <0.000091 0.0100 0.0060 <2 132 31 3.88 - - 07/16/19 10:51 N R N R N R N R N R N R >2420 - 54.0 - - - - - - <2 0.01 0.94 0.089 0.09 0.0014' 0.0010' 0.00008' <0.000091 0.0079 0.0064 2.5 133 40 N R - - 08/22/19 10:00 1.6 0.92 14.5 6.3 168.3 6.61 121 - 62.2 - - - - - - <2 0.03 0.81 0.120 0.10 0.0020 0.0014' 0.00009' <0.000022 0.0047 0.0054 <2 125 34 1.77 - - 08/22/19 10:01 NR NR NR NR NR NR 173 - 58.0 - - - - - - <2 0.02 0.81 0.118 0.11 0.0026 0.0016 0.00014' <0.000022 0.0067 0.0043' <2 120 29 NR - - 09/19/19 11:00 2.4 1.00 14.7 8.0 152.9 6.71 192 48.6 49.4 7.2 12.5 4.4 2.2 6.5 10.4 <2 0.02 0.99 0.095 0.07 0.0020 0.0015' 0.00020' 0.00003' 0.0087 0.0067 <2 124 23 5.86 2.70 2.93 09/19/19 11:01 NR NR NR NR NR NR 192 48.0 49.5 7.3 12.5 4.4 2.2 6.6 10.4 <2 0.02 0.99 0.090 0.07 0.0021 0.0014' 0.00027' 0.00005' 0.0084 0.0061 <2 123 20 NR 2.71 2.79 10/22/19 10:24 8.0 1.29 13.6 9.6 79.0 6.95 1203 - 29.2 - - - - - - 5 <0.007 0.18 0.212 0.11 0.0072 0.0038 0.00087 0.00013' 0.0456 0.0246 16 78 30 22.20 - - 10/22/19 10:25 NR NR NR NR NR NR 1553 - 28.5 - - - - - - 5 0.01 0.18 0.212 0.16 0.0071 0.0038 0.00084 0.00012' 0.0450 0.0246 18 75 27 NR - - 11/12/19 11:10 1.7 0.90 11.6 7.4 165.1 6.55 15 - 65.7 - - - - - - <2 0.03 0.68 0.093 0.08 0.0009' 0.0006 0.00003' 0.00007 0.0022 0.0029 <2 130 26 6.68 - - 11/12/19 11:11 NR NR NR NR NR NR 15 - 64.8 - - - - - - <2 0.04 0.68 0.096 0.08 0.0010' 0.0006 0.00005' 0.00002 0.0057 0.0022 <2 143 23 NR - - 12/10/19 9:40 2.0 0.96 9.1 9.8 149.3 6.78 31 53.6H1 56.9 8.0 13.9 5.4 2.3 7.4 9.1 <2 0.03 0.77 0.083 0.07 0.0048 0.0011 0.00008' 0.00003 0.0139 0.0107 <2 116 25 3.93 2.54 2.73 12/10/19 9:41 NR NR NR NR NR NR 31 53.4H1 57.2 7.9 14.0 5.4 2.2 7.4 9.2 <2 0.03 0.76 0.083 0.07 0.0038 0.0011 0.00005' 0.00003 0.0131 0.0104 2 120 24 NR 2.53 2.77 01/16/20 11:15 5.7 1.24 7.2 12.2 122.5 6.94 248 - 42.6 - - - - - - <2 0.03 0.65 0.085 0.06 0.0023 0.0012' 0.00044 0.00012' 0.0363 0.0283 4.5 105 40 14.00 - - 01/16/20 11:16 NR NR NR NR NR NR 308 - 41.7 - - - - - - <2 0.03 0.65 0.084 0.05 0.0020 0.0011' 0.00038 0.00014' 0.0351 0.0281 5 104 34 NR - - 02/10/20 11:25 2.8 1.06 9.1 10.6 141.2 6.80 36 50.2 50.8 7.5 12.6 4.7 1.8 6.8 8.6 <2 0.03 1.20 0.084 0.06 0.0010 <0.00027 0.00008 0.00004' 0.0107 0.0095 <1 116 31 3.49 1.88 2.29 02/10/20 11:26 NR NR NR NR NR NR 50 50.0 50.8 7.5 12.6 4.7 1.9 6.8 8.6 <2 0.03 1.19 0.084 0.06 0.0010 <0.00027 0.00008 0.00002' 0.0104 0.0093 <1 123 25 NR 1.93 2.22 03/17/20 10:25 2.3 1.02 7.7 10.9 142.9 6.94 42 - 55.3 - - - - - - 7 <0.006 0.94 0.068 0.05 0.0013 0.0009 0.00017' 0.00003 0.0120 0.0084 <1 122 27 5.41 - - 03/17/20 10:26 NR NR NR NR NR NR 40 - 55.0 - - - - - - 7 <0.006 0.93 0.066 0.05 0.0014 0.0008 0.00025' 0.00002 0.0122 0.0080 <1 119 34 NR - - 04/09/20 10:35 1.8 1.06 10.6 10.1 148.8 6.76 48 - 53.5 - - - - - - <2 <0.006 0.79 0.117 0.05 0.0007' <0.00027 0.00004' <0.000016 0.0100 0.0066 2 112 26 3.09 - - 04/09/20 10:36 NR NR NR NR NR NR 31 - 53.5 - - - - - - <2 0.01 0.79 0.075 0.05 0.0007' <0.00027 0.00002' <0.000016 0.0076 0.0077 <1 120 29 NR - - 05/14/20 10:35 1.1 0.96 12.2 8.0 140.5 6.83 48 56.2 54.1 6.9 13.1 5.2 2.1 6.9 7.9 5 0.02 0.79 0.087 0.07 0.0009' 0.0011' 0.00008' <0.00002' 0.0083 0.0078 <1 118 26 6.39 1.64 2.27 05/14/20 10:36 NR NR NR NR NR NR 55 56.2 53.5 6.9 13.0 5.1 2.1 6.8 7.9 4 0.02 0.78 0.087 0.07 0.0008' 0.0011' 0.00008' 0.00002' 0.0081 0.0075 <1 115 29 NR 1.61 2.04 06/06/20 11:00 2.4 1.08 13.3 9.0 108.5 6.87 436 - 41.0 - - - - - - 2 0.09 0.55 0.090 0.06 0.0023 0.0020 0.00030' 0.00004' 0.0265 0.0163 <2 92 19 9.28 - - 06/06/20 11:01 NR NR NR NR NR NR 548 - 41.3 - - - - - - 2 0.01 0.55 0.091 0.06 0.0023 0.0020 0.00030' 0.00005' 0.0257 0.0158 2.5 96 26 NR - - Maximum 11:25 8.0 1.29 15.1 12.2 168.8 7.0 1771 56 65 8.0 14.0 5.4 2.3 7.4 10.4 7 0.05 1.20 0.2120 0.135 0.0072 0.0038 0.0009 0.00013 0.0453 0.0246 17 136.5 35.5 22.20 2.7 2.9 Median 10:35 2.1 1.01 11.9 9.3 145.9 6.8 88 52 54 7.4 12.8 4.9 2.2 6.8 8.9 <2 0.02 0.79 0.0903 0.070 0.0014 0.0011 0.0001 0.00004 0.0098 0.0079 <1 118.8 27.1 5.64 2.2 2.5 Minimum 9:40 1.1 0.90 7.2 6.3 79.0 6.6 15 48 21 6.9 12.5 4.4 1.9 6.6 7.9 <2 <0.006 0.18 0.0425 0.030 0.0007 <0.00027 0.00002 <0.000022 0.0040 0.0026 <1 52.5 20.0 1.77 1.6 2.2 Summer Seasonal' 10:55 2.0 0.98 14.6 7.7 160.6 6.7 342 48 52 7.3 12.5 4.4 2.2 6.6 10.4 <2 0.02 0.87 0.0915 0.080 0.0022 0.0015 0.0002 0.00004 0.0088 0.0063 <2 123.0 26.9 4.87 2.7 2.9 Winter Seasonal' 10:30 2.1 1.04 9.9 9.9 142.1 6.8 42 54 54 7.5 13.1 5.2 2.1 6.9 8.6 <2 0.02 0.78 0.0835 0.065 0.0011 0.0007 0.0001 0.00003 0.0113 0.0088 <2 117.3 27.1 5.90 1.9 2.3 FY1213toFY1516 1 Maximum 12:54 ND 2.60 15.9 12.4 191.6 8.7 2076 88 86 5.9 18.0 8.9 2.8 9.0 11.0 5 0.12 1.70 1.8500 2.500 0.0115 0.0044 0.0085 0.00057 0.1100 0.0600 253.8 165.0 120.0 185.00 3.2 3.0 Median 10:21 ND 1.73 12.8 8.0 143.8 7.0 68 54 55 5.4 14.9 5.7 2.4 7.9 7.0 <2 0.03 0.81 0.1225 0.099 0.0010 0.0010 0.0005 0.00050 0.0050 0.0050 2.0 114.0 33.0 4.26 2.1 2.1 Minimum 10:07 ND 0.85 5.4 5.0 12.1 6.4 8 8 22 2.2 6.0 1.8 1.3 2.3 2.6 <2 <0.006 0.31 0.0415 0.025 <0.0003 0.0005 0.0000 0.00000 0.0019 0.0013 <2 13.0 5.0 1.32 1.2 1.7 Summer Seasonal' 10:28 ND 0.85 14.4 7.3 146.5 6.9 74 58 57 5.2 17.0 7.9 2.7 8.2 6.5 <2 0.03 0.79 0.1250 0.103 0.0010 0.0010 0.0005 0.00050 0.0050 0.0050 2.0 120.0 30.0 3.40 1.8 1.9 Winter Seasonal' 10:11 ND 2.60 9.9 8.6 142.0 7.1 63 51 54 5.5 13.5 4.7 2.1 6.6 7.5 <2 0.03 0.84 0.1175 0.082 0.0010 0.0010 0.0005 0.00040 0.0065 0.0050 2.0 110.0 35.0 4.89 2.8 2.5 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit); NA-Not Applicable; ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 50 Table B.4 Boones Ferry Creek at Bryant Rd,Instream Monitoring Results,FY1920 ■ Water Specific E.coli Alkalinity Hardness, NH3, NO3, PO4, Total Q Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na 504 BOD5 as N as N Total P as P Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSS" TDS TVS Turbidity TOC DOC Date Time (cfs) (°C) (mg/L) (µS/cm) pH 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) (mg/L) (mg/L) 07/16/19 12:00 0.1 16.3 9.30 193.4 7.85 47 - 65.6 - - - - - - <2 0.01 3.24 0.092 0.09 0.0014' 0.0006' 0.00020J <0.000091 0.017 0.012 3.5 159 47 3.52 - - 08/22/19 11:30 0.0 15.0 7.52 208.4 7.06 11 - 77.3 - - - - - - <2 0.02 2.85 0.108 0.10 0.0023 0.0011' 0.00016J <0.000022 0.027 0.021 <2 159 38 2.52 - - 09/19/19 12:30 0.2 16.0 7.38 111.4 6.64 291 34 34.5 3.9 8.6 3.1 3.0 4.4 7.5 <2 0.01 1.11 0.124 0.11 0.0054 0.0044 0.00020J 0.00004' 0.020 0.017 <2 96 34 3.80 3.46 3.77 10/22/19 10:55 0.3 13.6 7.93 127.6 6.54 345 - 41.4 - - - - - - <2 <0.007 1.31 0.114 0.10 0.0069 0.0044 0.00030J 0.00006' 0.020 0.016 3.0 104 29 2.93 - - 11/12/19 12:15 0.2 12.7 7.83 192.1 6.80 86 - 69.2 - - - - - - 2 0.03 3.13 0.098 0.09 0.0023 0.0018 0.00006' 0.00002 0.026 0.023 <2 159 42 2.59 - - 12/10/19 11:20 0.1 10.9 9.42 164.9 6.72 20 42 55.4 9.6 13.6 5.2 3.4 7.5 12.5 <2 0.08 2.30 0.088 0.09 0.0060 0.0015' 0.00011' 0.00003' 0.014 0.011 2.0 135 29 4.91 1.57 1.75 01/16/20 12:20 1.0 8.0 10.21 173.4 6.53 40 - 54.3 - - - - - - <2 <0.007 1.95 0.062 0.06 0.0020 0.0016' 0.00015 0.00004' 0.034 0.031 <2 133 60 4.81 - - 02/10/20 12:20 0.4 9.7 9.75 184.2 6.76 13 41 59.5 10.0 14.6 5.6 3.8 9.6 13.1 <2 0.01 5.69 0.101 0.09 0.0013 <0.00027 0.00002 0.00001' 0.022 0.021 <1 159 38 1.61 1.32 1.54 03/17/20 11:35 0.2 8.9 10.02 135.5 6.72 32 - 61.0 - - - - - - 10 <0.006 3.64 0.081 0.08 0.0015 0.0012 0.00011' <0.000016 0.027 0.023 <1 145 44 1.60 - - 04/09/20 11:30 0.2 10.8 9.59 191.8 6.72 20 - 60.4 - - - - - - <2 <0.006 3.22 0.087 0.09 0.0015' <0.00027<0.0000067<0.000016 0.019 0.016 <1 148 35 1.26 - - 05/14/20 12:15 0.1 12.5 8.62 180.4 6.80 7 65 68.0 8.7 16.5 6.5 4.1 9.0 11.0 4 <0.006 2.52 0.096 0.09 0.0016J 0.0022 0.00020J 0.00002' 0.022 0.022 <1 155 44 3.55 1.94 2.27 06/16/20 12:25 0.2 14.0 7.29 115.9 6.65 105 - 43.8 - - - - - - 2 0.03 1.13 0.108 0.09 0.0035 0.0033 0.00010J 0.00006' 0.028 0.021 3.5 107 28 3.53 - - Maximum 12:30 1.0 16.3 10.21 208.4 7.85 345 65 77.3 10.0 16.5 6.5 4.1 9.6 13.1 10 0.08 5.69 0.124 0.11 0.0069 0.0044 0.00030 0.00006 0.034 0.031 3.5 159 60 4.91 3.46 3.77 Geomean 12:07 0.2 12.6 8.96 176.9 6.72 36 42 60.0 9.2 14.1 5.4 3.6 8.3 11.8 <2 0.01 2.69 0.097 0.09 0.0022 0.0016 0.00013 0.00003 0.022 0.021 <2 147 38 3.23 1.76 2.01 Minimum 10:55 0.0 8.0 7.29 111.4 6.53 7 34 34.5 3.9 8.6 3.1 3.0 4.4 7.5 <2 <0.006 1.11 0.062 0.06 0.0013 <0.00027<0.0000067<0.000016 0.014 0.011 <1 96 28 1.26 1.32 1.54 Summer Seasonal' 12:12 0.1 15.5 7.45 154.7 6.86 76 34 54.7 3.9 8.6 3.1 3.0 4.4 7.5 <2 0.02 1.99 0.108 0.10 0.0029 0.0022 0.00018 0.00004 0.024 0.019 2.3 133 36 3.53 3.46 3.77 Winter Seasonal' 11:55 0.2 10.9 9.51 176.9 6.72 26 42 60.0 9.6 14.6 5.6 3.8 9.0 12.5 <2 <0.007 2.83 0.092 0.09 0.0018 0.0016 0.00011 0.00002 0.022 0.021 <2 147 40 2.76 1.57 1.75 FY1213 to FY1516 I Maximum 13:28 ND 16.1 12.15 219.5 8.61 1046 87 96.0 39.0 25.0 7.4 5.1 14.0 17.0 51 0.10 6.20 1.000 0.25 0.0130 0.0041 0.00660 0.00050 0.120 0.042 100.0 290 160 38.70 3.20 8.60 Geomean 10:49 ND 13.2 8.20 180.8 7.05 17 52 62.0 8.2 16.6 6.2 4.2 9.9 12.2 <2 0.03 3.30 0.125 0.11 0.0012 0.0010 0.00050 0.00050 0.015 0.013 3.3 160 44 2.26 1.88 1.87 Minimum 9:12 ND 3.3 2.56 69.8 6.49 1 3 23.3 2.5 5.9 2.1 2.0 3.4 4.4 <2 <0.006 0.05 0.050 0.03 0.0009 0.0006 0.00003 <0.00009 0.005 0.005 <2 10 17 0.84 1.60 1.50 Summer Seasonal' 11:01 ND 14.9 7.86 193.8 7.13 17 62 72.0 9.6 19.0 7.3 4.7 11.0 12.3 <2 0.03 3.00 0.131 0.12 0.0011 0.0010 0.00050 0.00050 0.013 0.010 5.0 170 47 2.53 1.89 1.93 Winter Seasonal' 10:36 ND 10.9 8.38 178.8 7.03 18 45 58.5 6.4 14.0 4.8 3.8 8.1 8.5 <2 0.02 3.60 0.125 0.10 0.0014 0.0010 0.00050 0.00035 0.017 0.015 2.0 150 42 2.09 1.87 1.81 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit);NA-Not Applicable;ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 51 Table B.5 Ball Creek bel Kruse Way,Instream Monitoring Results,FY1920 Water Specific E.coli Alkalinity Hardness, NH3, NO3, PO4, Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na SO4 BODS as N as N Total P as P Total Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSSNN TDS TVS Turbidity TOC DOC Date Time Q(cfs) (°C) (mg/L) (µS/cm) Ph 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) (mg/L) (mg/L) 07/16/19 9:40 0.4 16.3 9.30 193.4 7.85 291 - 69.2 - - - - - - <2 <0.001 0.52 0.083 0.08 0.0024 0.0017' 0.0002' <0.000091 0.016 0.010 2.5 138 34 5.34 - - 08/22/19 11:30 0.3 14.8 9.56 188.2 7.91 >2420 - 82.5 - - - - - - <2 0.01 0.55 0.104 0.09 0.0079 0.0047 0.0004' 0.00003' 0.019 0.010 3.5 138 26 3.65 - - 09/19/19 13:35 1.0 15.4 9.70 164.7 7.66 276 55.1 54.5 6.9 12.9 5.4 1.8 7.0 9.9 <2 0.02 1.14 0.072 0.06 0.0032 0.0025 0.0002' 0.00002' 0.020 0.015 <2 122 33 5.26 2.59 2.76 10/22/19 11:40 0.7 13.7 9.79 88.0 7.49 1203 - 30.1 - - - - - - 3 <0.007 0.08 0.166 0.13 0.0077 0.0051 0.0004' 0.00010' 0.032 0.020 3.5 73 36 10.10 - - 11/12/19 12:55 0.8 10.3 10.61 166.1 7.61 >2420 - 67.9 - - - - - - 6 0.02 0.33 0.222 0.16 0.0104 0.0076 0.0004' 0.00008 0.030 0.018 6.5 139 39 8.14 - - 12/10/19 12:10 0.7 9.1 11.46 160.0 7.60 88 61.6H1 61.8 6.8 13.7 6.7 1.4 7.6 7.7 <2 0.01 0.76 0.068 0.06 0.0053 0.0032 0.0010 0.00050' 0.016 0.011 2.5 120 23 4.00 1.93 2.14 01/16/20 12:50 2.2 8.0 12.10 135.4 7.62 96 - 45.9 - - - - - - <2 0.02 0.90 0.060 0.04 0.0026 0.0018i 0.0002 0.00005' 0.030 0.021 5.0 133 60 8.38 - - 02/10/20 13:20 0.9 8.8 11.28 160.5 7.81 130 60.6 59.6 7.6 13.8 6.1 1.1 7.6 8.9 <2 0.02 0.88 0.044 0.04 0.0014 <0.00027 0.0001 <0.000016 0.019 0.016 <1 123 21 2.71 1.42 1.72 03/17/20 12:20 1.6 8.3 11.03 159.9 7.82 71 - 63.3 - - - - - - 6 <0.001 0.85 0.041 0.04 0.0026 0.0019 0.0012 0.00040 0.024 0.018 <1 118 35 4.04 - - 04/09/20 12:15 0.6 11.2 10.46 176.9 7.81 25 - 62.5 - - - - - - <2 0.02 0.64 0.051 0.04 0.0011i <0.00027 0.00003i <0.000016 0.021 0.015 <1 126 51 3.07 - - 05/14/20 13:15 3.9 13.0 9.92 100.9 7.77 2420 36.5 36.7 4.6 8.6 3.7 2.1 4.8 5.6 10 0.02 0.22 0.232 0.09 0.0246 0.0172 0.0014 0.00020' 0.161 0.088 3.5 79 43 32.60 12.22 11.17 06/16/20 13:05 1.0 13.4 9.50 114.1 7.75 285 - 60.3 - - - - - - 2 0.03 0.26 0.093 0.04 0.0035 0.0028 0.0001' 0.00004' 0.015 0.008 <1 113 27 9.34 - - Maximum 13:35 3.9 16.3 12.10 193.4 7.91 >2420 61.6 82.5 7.6 13.8 6.7 2.1 7.6 9.9 10 0.03 1.14 0.232 0.16 0.0246 0.0172 0.0014 0.00050 0.161 0.088 6.5 139 60 32.60 12.22 11.17 Median 12:35 0.8 12.1 10.19 160.3 7.76 281 57.9 61.1 6.9 13.3 5.8 1.6 7.3 8.3 <2 0.02 0.60 0.078 0.06 0.0034 0.0027 0.0003 0.00005 0.020 0.016 2.5 123 35 5.30 2.26 2.45 Minimum 9:40 0.3 8.0 9.30 88.0 7.49 25 36.5 30.1 4.6 8.6 3.7 1.1 4.8 5.6 <2 <0.001 0.08 0.041 0.04 0.0011 <0.00027 0.0000 <0.000016 0.015 0.008 <1 73 21 2.71 1.42 1.72 Summer Seasonal' 12:17 0.7 15.1 9.53 176.5 7.80 288 55.1 64.8 6.9 12.9 5.4 1.8 7.0 9.9 <2 0.02 0.54 0.088 0.07 0.0034 0.0027 0.0002 0.00004 0.018 0.010 <2 130 30 5.30 2.59 2.76 Winter Seasonal' 12:35 0.8 9.7 10.82 160.0 7.70 113 60.6 60.7 6.8 13.7 6.1 1.4 7.6 7.7 2 0.02 0.70 0.064 0.05 0.0040 0.0026 0.0004 0.00009 0.027 0.018 3.0 122 38 6.09 1.93 2.14 FY1213 to FY1516 Maximum 15:08 ND 17.7 14.72 222.6 8.53 >2420 110.0 94.0 7.1 18.0 11.0 1.8 9.3 9.4 3 0.10 3.00 0.930 0.21 0.0140 0.0130 0.0025 0.01700 0.057 0.044 72.5 190 69 91.00 4.22 4.60 Median 12:30 ND 13.3 9.96 172.9 7.87 138 70.5 69.0 6.5 16.5 8.4 1.6 8.6 6.9 <2 0.03 0.74 0.099 0.07 0.0020 0.0011 0.0005 0.00050 0.016 0.011 2.9 140 37 3.50 2.35 2.25 Minimum 10:20 ND 5.3 4.58 45.6 6.04 4 14.0 20.0 3.6 8.0 2.5 1.4 3.8 4.9 <2 <0.001 0.16 0.005 0.03 0.0003 0.0008 0.0001 <0.000009 0.005 0.002 <2 49 5 1.03 1.80 1.60 Summer Seasonal' 12:30 ND 15.1 9.50 195.0 7.92 210 80.5 80.0 6.5 17.4 10.0 1.6 9.2 6.2 <2 0.03 0.67 0.125 0.10 0.0022 0.0011 0.0005 0.00050 0.015 0.005 3.8 150 39 3.07 1.90 1.80 Winter Seasonal' 12:30 ND 10.9 10.55 165.3 7.83 108 62.5 65.0 6.1 16.0 6.2 1.6 7.5 8.8 <2 0.02 0.78 0.092 0.05 0.0019 0.0011 0.0005 0.00050 0.018 0.013 2.7 120 36 4.11 2.80 2.70 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit);NA-Not Applicable;ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 52 Table B.6 Carter Creek abv Bangy Rd,Instream Monitoring Results,FY1920 Water Specific E.coli Alkalinity Hardness NH3, NO3, PO4, Total Total Temp DO Conduct (MPN/ as CaCO3 as CaCO3 CL2 Ca Mg K Na 504 BODS as N as N Total P as P Cu Diss Cu Total Pb Diss Pb Zn Diss Zn TSSNN TDS TVS Turbidity TOC DOC Date Time Q(cfs) (°C) (mg/L) (µS/cm) Ph 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) (mg/L) (mg/L) 07/16/19 13:30 0.4 20.1 4.46 255.2 7.19 461 - 101.0 - - - - - - <2 0.05 0.11 0.120 0.04 0.0019' 0.0012' 0.0002' <0.000091 0.014 0.004 5.0 171 32 8.68 - - 08/22/19 12:00 0.2 17.6 4.81 238.7 7.23 172 - 99.0 - - - - - - <2 0.05 0.21 0.143 0.06 0.0034 0.0024 0.0002' 0.00004' 0.007 0.004 5.5 163 45 6.52 - - 09/19/19 14:30 1.1 16.3 7.00 185.3 7.08 236 55.7 67.3 9.8 16.9 6.1 2.8 6.1 11.2 <2 0.06 1.54 0.089 0.04 0.0036 0.0028 0.0003' 0.00002' 0.014 0.006 2.0 137 41 6.34 4.76 4.94 10/22/19 12:05 1.4 13.9 8.15 168.3 7.18 210 - 58.1 - - - - - - 2 0.02 0.24 0.107 0.07 0.0047 0.0029 0.0002' 0.00005' 0.017 0.012 4.5 115 26 5.50 - - 11/12/19 13:25 0.7 10.3 10.61 166.1 7.61 81 - 125.1 - - - - - - 2 0.10 0.14 0.156 0.04 0.0034 0.0011 0.0004' 0.00002 0.036 0.007 12.5 188 37 17.30 - - 12/10/19 12:50 0.3 8.3 9.47 225.2 7.17 28 82.4H1 90.6 12.5 21.1 9.2 2.6 8.4 10.8 <2 0.05 0.57 0.078 0.03 0.0029 0.0014' 0.0001' 0.00003' 0.010 0.006 3.5 147 30 8.78 3.21 3.25 01/16/20 13:25 3.1 7.0 11.86 154.6 7.16 397 - 53.9 - - - - - - <2 0.03 0.53 0.062 0.03 0.0027 0.0017' 0.0003 0.00003' 0.041 0.033 5.5 111 42 11.90 - - 02/10/20 13:50 0.7 8.0 10.96 240.5 7.39 50 90.3 96.0 13.2 22.6 9.6 2.1 9.6 12.2 <2 0.09 0.76 0.081 0.03 0.0016 <0.00027 0.0001 <0.000016 0.014 0.009 6.6 168 36 9.65 2.23 2.54 03/17/20 12:50 1.1 8.1 10.84 183.0 7.42 37 - 98.7 - - - - - - 10 0.05 0.67 0.057 0.02 0.0014 0.0009 0.0001' <0.000016 0.013 0.007 <1 170 47 6.16 - - 04/09/20 12:50 0.5 12.4 8.84 271.7 7.43 9 - 104.0 - - - - - - <2 0.05 0.46 0.087 0.03 0.0018' <0.00027 0.0002' <0.000016 0.010 0.005 <1 186 41 11.00 - - 05/14/20 14:05 2.5 13.2 8.66 211.2 7.50 649 88.5 87.6 10 20.4 8.9 1.8 8.0 7.5 6 0.04 0.30 0.177 0.04 0.0044 0.0029 0.0006 0.00005' 0.020 0.009 2.5 146 40 23.60 5.13 5.25 06/06/20 13:50 1.0 14.6 8.47 135.6 7.32 270 - 47.9 - - - - - - 4 0.02 0.47 0.071 0.05 0.0036 0.0030 0.0002 0.00005' 0.034 0.021 2.0 99 22 8.22 - - Maximum 14:30 3.1 20.1 11.86 271.7 7.61 649 90.3 125.1 13.2 22.6 9.6 2.8 9.6 12.2 10 0.10 1.54 0.177 0.07 0.0047 0.0030 0.0006 0.00005 0.041 0.033 12.5 188 47 23.60 5.13 5.25 Median 13:25 0.8 12.8 8.75 198.3 7.28 191 85.5 93.3 11.3 20.8 9.1 2.4 8.2 11.0 <2 0.05 0.47 0.088 0.04 0.0032 0.0016 0.0002 0.00003 0.014 0.007 4.0 155 38 8.73 3.99 4.10 Minimum 12:00 0.2 7.0 4.46 135.6 7.08 9 55.7 47.9 9.8 16.9 6.1 1.8 6.1 7.5 <2 0.02 0.11 0.057 0.02 0.0014 <0.00027 0.0001 <0.000016 0.007 0.004 <1 99 22 5.50 2.23 2.54 Summer Seasonal' 13:40 0.7 17.0 5.91 212.0 7.21 253 55.7 83.2 9.8 16.9 6.1 2.8 6.1 11.2 <2 0.05 0.34 0.105 0.05 0.0035 0.0026 0.0002 0.00004 0.014 0.005 3.5 150 37 7.37 4.76 4.94 Winter Seasonal' 13:07 0.9 9.3 10.04 197.1 7.41 66 88.5 93.3 12.5 21.1 9.2 2.1 8.4 10.8 <2 0.05 0.50 0.084 0.03 0.0028 0.0013 0.0002 0.00003 0.015 0.008 4.0 158 38 10.33 3.21 3.25 FY1213 to FY1516 Maximum 15:30 ND 21.0 12.95 314.8 12.20 >2420 130.0 150.0 8.9 27.0 12.0 2.7 11.0 19.0 3 0.54 2.00 0.650 0.25 0.0071 0.0056 0.0020 0.00050 0.049 0.030 37.5 210 140 68.30 5.60 5.10 Median 12:50 ND 14.0 7.42 229.7 7.51 105 95.0 100.0 7.7 25.0 10.4 2.1 10.2 8.0 <2 0.04 0.45 0.110 0.06 0.0015 0.0010 0.0005 0.00040 0.011 0.005 3.8 160 40 6.35 3.92 3.77 Minimum 9:45 ND 4.4 2.79 75.1 6.94 10 2.5 29.3 3.1 7.6 2.5 1.6 3.0 4.3 <2 <0.001 0.06 0.025 0.03 0.0009 0.0006 <0.000016 <0.000016 0.004 0.002 <2 73 13 1.13 3.00 2.70 Summer Seasonal' 12:56 ND 17.4 5.78 252.6 7.50 155 100.5 110.0 7.9 26.7 11.0 2.2 11.0 5.8 <2 0.04 0.22 0.125 0.09 0.0021 0.0010 0.0005 0.00020 0.006 0.005 4.2 180 43 7.38 4.04 3.83 Winter Seasonal' 12:42 ND 10.8 8.58 219.6 7.51 79 85.5 91.0 6.2 18.0 6.6 2.0 6.9 17.0 <2 0.04 0.54 0.088 0.05 0.0014 0.0010 0.0005 0.00045 0.012 0.009 2.5 150 38 6.15 3.71 3.15 Notes: 1-Median seasonal concentration; H1-Analysis completed out of hold time;J-Estimated result(between the method reporting limit and method detection limit);NA-Not Applicable;ND-No Data; NS-Not Sampled; NN-Parameter not accredited under NELAP for the analytical method used;<,> -Result at method detection limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 53 Table B.7 Wet Weather Results at Reese Rd and at South Shore Blvd,October 16,2019 Storm Event Precipitation=0.39 Inches; Prey 24-hr Precipitation=0 Water Specific E.coli Alkalinity Hardness NH3, NO3,as Flow Temp Conduct DO (MPN/ as CaCO3 (as CaCO3) BOD5 as N N Total P PO4,as Total Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSS" TDS TVS Turbidity Sample ID Time (cfs) (°C) (µS/cm) pH (mg/L) 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) P(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) South Shore Grab Sample 1 12:00 1.43 12.5 70.2 6.91 10.11 2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 52.9 South Shore Grab Sample Dup 1 12:01 NR NR NR NR NR >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR South Shore Grab Sample 2 13:00 2.01 13.0 43.3 6.92 9.80 >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 24.3 South Shore Grab Sample Dup 2 13:01 NR NR NR NR NR >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR South Shore Grab Sample 3 14:10 1.18 13.2 44.5 5.88 9.89 >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR1 South Shore Grab Sample Dup 3 14:11 NR NR NR NR NR >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR South Shore Composite Sample 14:30 NA NA NA NA NA NA 13.9 20.4 12 0.08 0.23 0.229 0.15 0.0190 0.0116 0.0026 0.00017 0.365 0.201 41.5 56 39 NA South Shore Composite Sample Dup 14:31 NA NA NA NA NA NA 13.8 19.5 11 0.09 0.23 0.223 0.15 0.0183 0.0112 0.0024 0.00015 0.354 0.211 37.5 65 37 NA Reese Rd Grab Sample 1 11:15 0.37 14.6 88.5 7.1 6.64 727 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 149.0 Reese Rd Grab Sample 2 12:30 0.87 14.6 39.9 7.2 7.63 326 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 57.6 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA Reese Rd Grab Sample 3 13:30 0.37 14.9 41.3 7.2 6.50 236 47.6 Reese Rd Composite Sample 13:45 NA NS NS NS NS NA 10.7 13.4 9 0.32 0.21 0.259 0.18 0.0121 0.0070 0.0021 0.00015' 0.095 0.052 36 51 31 NS Reese Rd Blank 13:50 NA NA NA NA NA <1 NA2 0.2 <2 0.07 <0.005 <0.01 <0.01 0.0019' 0.0018J 0.0002' 0.00015' 0.002' 0.003 <2 164 29 NA Notes: J-Estimated result(between the method reporting limit and method detection limit);NN-Parameter not accredited under NELAP for the analytical method used; NA-Not Applicable; NR-Not Recorded;<,> -Result at method reporting limit shown; 1-Turbidity was run but not recorded;2-pH was too low(4.2)to complete the analysis City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 54 Table B.8 Wet Weather Results at Reese Rd and at South Shore Blvd,June 6,2020 Storm Event Precipitation=0.36 Inches; Prey 24-hr Precipitation=0 Water Specific E.coli Alkalinity Hardness NH3, NO3,as Flow Temp Conduct DO (MPN/ as CaCO3 (as CaCO3) BODs as N N Total P PO4,as Total Cu Diss Cu Total Pb Diss Pb Total Zn Diss Zn TSS" TDS TVS Turbidity Sample ID Time (cfs) (°C) (µS/cm) pH (mg/L) 100mL) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) P(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (NTU) South Shore Grab Sample 1 13:25 1.21 14.2 31.7 7.15 7.75 1553 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 51.2 South Shore Grab Sample Dup 1 13:26 NR NR NR NR NR 1414 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR South Shore Grab Sample 2 17:15 0.65 14.0 30.7 6.86 10.09 649 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 50.2 South Shore Grab Sample Dup 2 17:16 NR NR NR NR NR 1046 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NR South Shore Composite Sample 17:50 NA NA NA NA NA NA 8.7 12.4 7 0.06 0.23 0.181 0.05 0.0106 0.0058 0.0015 0.00011J 0.067 0.139 48.0 37 48 NA South Shore Composite Sample Dup 17:51 NA NA NA NA NA NA 8.9 11.8 9 0.09 0.23 0.174 0.05 0.0107 0.0058 0.0014 0.00012J 0.066 0.130 17.0 40 43 NA Reese Rd Grab Sample 1 12:50 0.25 16.2 88.2 7.5 4.23 124 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 91.8 Reese Rd Grab Sample 2 16:45 0.17 16.7 87.2 7.9 8.01 >2420 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 109.0 Reese Rd Composite Sample 17:40 NA NS NS NS NS NA 22.9 37.0 20 0.23 0.13 0.270 0.04 0.0098 0.0050 0.0034 0.00040' 0.092 0.140 48 78 45 NS Reese Rd Blank 16:35 NA NA NA NA NA <1 <1.7 0.1J <1 <0.006 0.02 <0.0043 0.01 0.0005' <0.00027 <0.00000666 0.00003' 0.006 0.102 <2 <10 <10 NA Notes: J-Estimated result(between the method reporting limit and method detection limit); NN-Parameter not accredited under NELAP for the analytical method used; NA-Not Applicable;NR-Not Recorded;<,> -Result at method reporting limit shown City of Lake Oswego MS4 and TMDL Annual Report, FY1920 Page 55 APPENDIX C TMDL IMPLEMENTATION PLAN, FY1920 ANNUAL REPORT City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 56 This page intentionally left blank City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 57 City of Lake Oswego, Oregon TMDL IMPLEMENTATION PLAN ANNUAL REPORT COVERING JULY 1, 2019 TO JUNE 30, 2020 Prepared for the Oregon Department of Environmental Quality October 31, 2020 Alicw8Q1111 EGO� City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 58 This page intentionally left blank City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 59 C.1. Introduction The Clean Water Act (CWA) was enacted in 1972 to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters". After point sources such as industrial facilities and wastewater treatment plants were regulated as part of the National Pollutant Discharge Elimination System (NPDES) program, the USEPA found that the nation's rivers and streams were still not providing sufficient water quality to meet their assigned beneficial uses. As a consequence, the NPDES Municipal Separate Storm Sewer System (MS4) Phase I permit program was implemented in 1990 to regulate stormwater discharges from municipalities, counties, and other entities that met the MS4 permit thresholds of a population of 100,000 people or in an urbanized area. After the Phase I and Phase II NPDES MS4 permits were implemented, it was determined that certain watersheds needed a further reduction of pollutants to provide the water quality necessary to attain their assigned beneficial uses. Under Section 303(d)of the CWA,entities that administer the CWA must identify watersheds that do not have sufficient water quality to meet their strictest beneficial use. In Oregon,the Department of Environmental Quality (DEQ) administers the CWA. DEQ determines the total maximum daily load (TMDL) that each watershed can carry for all parameters that are keeping the watershed from achieving its most beneficial use. Entities which have non-point source discharges, such as counties and cities, are designated as management agencies (DMAs) for these parameters. The City of Lake Oswego (City)was determined to be a DMA for the several parameters in several watersheds (See Table C.1). Table C.1.TMDLs for Streams in Lake Oswego's Jurisdiction Issue Year TMDL Water Body Date Parameter • Springbrook Creek • Bacteria • Oswego Lake/Oswego Creek 2006 • Mercury • Tryon Creek • Temperature(target is effective shade) • Lower Willamette River • pH 1988 1988 • Chlorophyll a(target is phosphorus) to • Dissolved oxygen (target is total suspended solids(TSS)) 2014 • Tualatin River Updated 1988 parameters and added: 2001 • Temperature(target is effective shade) • Fanno Creek and its tributaries • Bacteria • Oswego Lake(for phosphorus only) Updated: • 2012 pH • Chlorophyll a(target is phosphorus) • DO(target pollutant is TSS) • Bacteria • Mercury 2014 2006 • Lower Willamette River • Temperature(target is effective shade) to 2019 • Tualatin River 20d2 • pH • Chlorophyll a(target is phosphorus) • DO(target is TSS) City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 60 C.2. TMDL Implementation Plan Revisions The Willamette River and Tualatin River have Water Quality Management Plans (WQMPs) associated with their TMDLs. These WQMPs provide guidance for reducing the parameters that have TMDLs. They require a revision of the City's TMDL Implementation Plan ("Plan") every five years. In FY1718,the City revised its Plan in response to DEQ's realignment of the Willamette River and Tualatin River WQMP timelines. The City submitted its revised TMDL Implementation Plan to DEQ on October 31, 2018 for their review and received approval in May 2020. C.2 Program Management The City uses funds from Planning and the Parks Department to fund many of the activities required in its Plan. Two programs, the Habitat Enhancement Program (HEP) and the Backyard Habitat Program, are directly funded by the City in support of habitat restoration and preservation. In FY1920, the City disbursed $71,522 for private projects and $252,478 for public projects through its HEP. The City disbursed $38,000 to fund the Backyard Habitat Program. The City provides access to its Plan, Hydromodification Assessment, and annual reports on its website. The City received no comments on these documents in FY1920. C.3 Development There were no comprehensive plan changes nor zoning changes that affected stormwater discharges. The urban services boundary did not change nor is it expected to change in FY2021. No concept planning or activities were completed in FY2021 that were associated with urban growth boundary changes or land annexation. Eight properties were annexed in FY1920(see Table C.2)with all but one of them located on the west side of the City. Of those 8 acres, 1.1 acres are impervious (13%). Five of the properties are zoned as R7.5 (7,500 ft2), one property is zoned as R-10, and one is zoned as R-15. All annexed into the City to connect to the public wastewater system and 5 indicated they were interested in further development of the property. Three of the annexations were properties that already have multiple tax lots; two properties were comprised of 2 tax lots and one property was comprised of 3 tax lots. Of the lots that cannot be further subdivided, two are zoned R7.5 and one is zoned R-10. As of October 1, 2020, there are two known annexations for FY2021. one is comprised of two tax lots totaling 0.42 acres and zoned as R-10. The other is 0.28 acres and is assumed to be zoned R7.5. Table C.2. Historical and Current Annexations and Impervious Area, FY1516 to FY1920 #of Impervious Impervious Impervious Properties Acres Area Created, Area in City Area in USB vs City Year Annexed Annexed Acres Limits,Acres USB,Acres Limits,Acres FY1920 8 8.2 1 2,393 2,584 191 FY1819 13 6.6 7 2,286 2,570 284 FY1718 9 4.0 5 2,279 2,567 288 FY1617 11 6.6 20 2,274 2,561 287 FY1516 27 22.0 19 2,200 2,555 355 City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 61 The City currently contains 11.4 sq mi (7,320 acres)within its boundaries with 33%of the area (3.7 sq mi) considered to be impervious (see Figure C.1). When including the impervious area in the City's urban services boundary,the impervious area is 4 square miles. Both are similar to last year's percentages which reinforces the perception that much of the City is developed and that development is either infill, partitions, or redevelopment of already existing impervious area. T 1 Nolt.)44 im .:_,7 ril. ,,,t,.. - •,..-. : ,- Z".1'r,/ vet.._, . . 41Tra.::;,1„,, ,,,,6,, ok.,.,,I, - , - --- -.. .N- 2: ,. ...- „V' \i' kiji- -•,,•J-- l';.-1-,r,--e1:7 kt'--1.'''1".' ,-;-5- --- .4 , . i `..1r�: �� "��L��k�,4' � � � '7� ,� . .�Y Imo''- -'�",�.� ���`�E�y���I 1'. f !/a ym k 31 I I; `k - A...,.,4*.....11.... , •• , 4116 ,1„.r..,4„.,: , "‘ _ N 0,... � 1 i k o, OS�690 La e r�. !i Lop --,ice �►' �' s ". , ,.:,-•:,,asofit. :# liti 4'43•A-4. 4.-A.44:". °'' .4.. '47' -r., 4ir . -tl.,,‘- .4,4, -' ..-„ i. .:1.1 L. � t_ �'.a fisto ! _ 11. Ffl�_1 r rv,1 x_ ''� • �' I^' acne An 4,- :', . . - .0",77`. . , . * .;''• .„,,, , 9r ' ' �u� °,Jr't ( �,� '�1�.-' -Mpervious Surfaces wihln Lake Oswego City Limits { 44 Vmpervlous Surfaces wihln Urban Services Area _._ ^ ':F f / I Urban Services Boundary ! kril F �_iv �u.l �: ti ParkoO------w Pe i u a :m.e Figure C.1. Impervious Area in Lake Oswego, FY1920 In FY1920, 19 land use applications were reviewed and 19 building permits were issued for projects that involved sensitive lands or were within 50 ft of a waterway. Property owners submitting land use applications are required by code to engage the services of licensed professionals to delineate sensitive lands designations. If not already delineated. The Planning Department reported that there were no delineations resulting in loss or increases in riparian buffers. C.4 Water Quality All of the constituents identified as needing a TMDL, except stream temperature, are regulated through the City's Phase I NPDES MS4 permit and have waste load allocations(WLAs). Historical progress towards attaining them is found in the City's 2016 Pollution Load Reduction Evaluation (PLRE) and 2016 WLA Assessment. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 62 The following actions address the TMDL parameters except for stream temperature (See Table C.3): • Implementation of an erosion control program and a street sweeping program to reduce total suspended solids, bacteria, phosphorous, and mercury while stabilizing pH. • Implementation of a development review program to reduce stormwater volume and streambank erosion thereby reducing phosphorus, temperature, and mercury while increasing dissolved oxygen. • Maintenance of stormwater conveyance and water quality facilities to reduce total suspended solids, phosphorous, mercury, and total suspended solids while increasing dissolved oxygen. • Implementation of a cross-connection program to reduce bacteria. • Implementation of an illicit discharge and pesticide reduction program to reduce phosphorus and mercury while increasing dissolved oxygen and stabilizing pH. Additional information regarding these programs is provided in the City's annual NPDEDS MS4 report and in Section C.7. Table C.3. TMDL Parameters and Example Related City Activities to Reduce Loads Temperature Chlorophyll a (Effective Dissolved Watershed/City Activity (Phosphorus) Mercury Shade) pH Oxygen(TSS1) Bacteria Erosion Control and Street Sweeping A/ 4 4 4 4 Development Review A/ 4 A/ 4 4 Maintenance of Stormwater Infrastructure and Water Quality Al Al Al Al Al Facilities Wastewater-Stormwater Cross Connections Illicit Discharge Program A/ 4 4 4 Public Education q A/ q A/ A/ Riparian Habitat Enhancement and Preservation 1 TSS—Total Suspended Solids Every month, the City collects instream water samples from six sites which are analyzed for 16 water quality parameters. Once every quarter,the City samples additional parameters from these sites(anions, cations, dissolved carbon, and total carbon). Field measurements such as stream temperature, dissolved oxygen, turbidity, conductivity, pH, and estimated discharge are also recorded when the samples are collected every month. Detailed water quality data collected as a part of the MS4 permit can be found in Appendix B of the City's MS4 report. Two of the sites in the City's monitoring network (Ball Creek and Carter Creek) discharge to Fanno Creek which is a tributary of the Tualatin River. The City also has sampling sites on Springbrook Creek, Boones Ferry Creek at Bryant Ave, and Lost Dog Creek; all of these sampling sites are located just upstream of their discharge to Oswego Lake. A sixth sampling site is located on Nettle Creek which is a tributary to Tryon Creek. Many of the TMDLs affecting the watersheds in the City's jurisdiction have wasteload allocations and are covered under the City's NPDES MS4 permit. An analysis of the current progress towards meeting the City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 63 WLAs is found in Section 5.4 of the City's annual NPDES MS4 report. The water quality data for FY1920 is included in Appendix B of the NPDES MS4 report. In summary, the pH WLA was reached in all of the monitored streams. The total phosphorous target concentrations, used as a surrogate measure, were met at Ball Creek, Carter Creek, and Lost Dog Creek. Springbrook Creek and the Boones Ferry site met the winter phosphorous threshold and only exceeded the summer threshold. Bacterial reductions have been more difficult for the City to achieve although it is notable that Springbrook Creek's winter median and geomean concentrations showed a reduction of 76% and 69% respectively, from the 1997-2003 data. The geomean concentration at the monitored sites was less than the 460 col/100 mL target except for Nettle Creek and the summer geomean concentration at Ball Creek. The E. Coli geomean concentration at Boones Ferry, Lost Dog Creek, Springbrook Creek (winter geomean only), and Carter Creek(winter geomean only) was under 100 col/100 mL. Using the summer geomean concentrations,the dissolved oxygen threshold was met at Ball Creek but not at Carter Creek. The surrogate measures for dissolved oxygen are total suspended solids(TSS)and volatile suspended solids (VSS); these concentrations show a steady decline from the late 1990's data and meet the 50% reduction required by the TMDL. C.5 Temperature Stream temperatures are affected by the amount of summer baseflow, stream channel widening due to erosion caused by short-term high-volume runoff, stormwater temperature, removal of riparian vegetation, and reduced diversity of riparian canopy. Of these causes, stormwater temperature is the least harmful because of the maritime climate in the Willamette Valley. A marine climate has mild rainy winters and hot dry summers resulting in very few rain events when air and stream temperatures are at their highest. The primary mechanism for reducing the mainstem Willamette River temperature is through preservation and restoration of streambank vegetation and cold-water refugia. Temperature maximums are set based on whether the stream is used for salmonid rearing, migration, or spawning. The monitored sites within the City's jurisdiction are cool-water habitat which requires a maximum temperature of 17.8°C. The surrogate measure, effective shade, is evaluated as new LiDAR data is received. The City received the most recent LiDAR data in Summer of 2020. In FY1920, Carter Creek was the only monitored site above the target temperature of 17.8°C (see Table C.4). All but the Boones Ferry site showed a temperature decrease from FY1213-FY1516 temperatures. The largest drop in stream temperature was at Lost Dog Creek. Table C.4. Stream Temperatures at Selected Sites in Lake Oswego, FY1920 and FY1213-FY1516 Target Temperature Summer Maximum, Stream °C FY1920 FY1213-FY1516 Ball Creek 17.8 16.3 17.7 Carter Creek 17.8 20.1 21.0 Boones Ferry site 17.8 16.3 16.1 Lost Dog Creek 17.8 17.3 20.6 Springbrook Creek 17.8 15.1 15.9 Nettle Creek 17.8 16.6 16.9 City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 64 The City addresses temperature loading through the following metrics: A. Preservation of existing riparian habitat through code enforcement of the sensitive lands Resource Protection (RP) overlay. B. Enhancement of existing riparian habitat by funding restoration of public and private properties and protecting or enhancing areas of cold-water refuge. C. Enhancement and protection of existing shade in riparian corridors through enforcement of the City's municipal code and by educating the public on the value of shade and trees. C.5.1 Preservation of Riparian Habitat The City's sensitive lands designation overlays 120 acres which encompasses most of the riparian corridors within its jurisdictions. Any development on properties with the riparian habitat overlay must mitigate negative impacts at a 1:1 ratio. There were 19 land use applications and 19 building permits including new construction and remodels/additions issued in FY1920 for properties with a sensitive land overlay or which were within 50 ft of a stream (see Figure C.2). The Planning Department reported that no development occurred in sensitive lands for private property projects. x S m 8 `%• - �e.� . . 1 m q�� ® 11 .f i J S ? i, 'A 1 iliv . 0 P • E CA%km .� s &� t'. e fy�inp ,yp` yRL Y t r�.. a 9av A m 0° yr ,,, le a y t --' p� / i s aw. w"'%0, b - 6, 4 , My .z�1 5 e % I £ ,„, .2 6 o y_ a "N j� r Cr. Rd 41 / IN .r.N I S'''. 0 0-5 1 ti rN mm� - a 4,:„ Miles Figure C.2 Properties with a Building Permit and Sensitive Lands or Within 50 ft of a Stream, FY1920 Other ways that the City protects riparian habitat is through code enforcement and modifications to municipal code. In FY1920, there were no modifications to the municipal code that affected sensitive lands, increased density, or increased the allowed impervious area for a zoning category. The Planning Department reported that there were only two investigations into sensitive lands violations in FY1920. Neither of the investigations resulted in a violation. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 65 C.5.2 Enhancement of Riparian Habitat The City provides enhancement of riparian habitat through restoration of City-owned properties, Master Planning of Parks, Neighborhood Grants, funding of the Habitat Enhancement Program (HEP), partnering with the Audubon Society's Backyard Habitat Program,and providing technical expertise to the three local watershed councils operating within the City's jurisdiction. C.5.2.1 Public Property Restoration The City's Master Plans for Woodmont Park has been completed. The Master Plan for Iron Mountain Park has begun implementation with construction of a wetland viewing area, restoration of the natural route of a stream, and wetland enhancement. It is expected that construction will be completed in FY2021. The City actively restores upland and riparian areas in its parks and it has very active neighborhood groups who participate in the process. In FY1920, there were almost 370 acres under active restoration. It is expected that some of the acreage will transition to a monitoring status in FY2021. Two capital improvements projects addressed sources of hydromodification in FY1920. The Lakeview Blvd Realignment project had a large raingarden constructed to treat and detain stormwater from approximately 0.28 acres of previously-untreated impervious area. It is expected to decrease the volume of stormwater entering the public system. The D Avenue project treated 3.34 acres of previously- untreated impervious area by constructing 12 swales and 27 raingardens; the facilities also reduce stormwater volume to Tryon Creek. In addition,the project reduced the number of outfalls and rerouted the outfall to a lower section of the creek thereby reducing the length of stream affected by hydromodification from the City's stormwater. The Wembley Park Rd project includes the construction of treatment facilities (primarily Contech StormFilters) and the reconstruction of several outfalls to enhance energy dissipation and reduce streambank erosion. The City worked with the USGS, City of Wilsonville, Meyer Memorial Trust, and Benton County Soil and Water Conservation District to map cold-water refugia (CWR)along the mainstem of the Willamette River. Four sites within the City's jurisdiction were monitored for water temperature: Tryon Creek, Oswego Creek, Glenmorrie Dr seep,and Arbor Creek seep. Two sites,Tryon Creek and the seep at Glenmorrie Dr, showed some promise as cold-water refugia with temperatures between 15 and 17° C from June to mid- September (see Figure C.3). The seep at Arbor Creek,while somewhat cooler than the Willamette River, neared or exceeded 20°C several times between June and mid-September. Oswego Creek did not provide consistent temperature recordings, however the temperatures that were recorded showed temperatures that were consistently near or exceeding 20°C. Because seeps do not provide a large volume of water for cold-water refugia, especially in comparison to the Willamette River's volume, the City's best area for protecting CWR is Tryon Creek. The City currently works with the Tryon Creek Watershed Council on riparian restoration and preservation through its Habitat Enhancement Program. More information on the CWR study can be found in the USGS Open-File Report (USGS OFR 2018-1184), "Water Temperature in Tributaries, Off-Channel Features, and Main Channel of the Lower Willamette River, Northwestern Oregon, Summers of 2016 and 2017". C.5.2.2 Private Property Restoration The City uses the HEP to provide funds to local watershed councils for projects that enhance riparian habitat and provide public education. Applications are prioritized according to the amount of riparian habitat enhanced, connectivity to City projects or past projects, public education hours, and whether the project is in an area undergoing severe hydromodification as determined by the 2016 Hydromodification City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 66 Assessment. In the last 5 fiscal years (FY1516 to FY1920),the City has provided funds to restore 35 acres through removal of invasive plants and installation of over 4,200 native trees and shrubs. ao- Arbor Cr Io-4523O122313p0 I EXPLANATION 25 -- Tributary Willamette River at Portland 1142117201 15 20 10 550 I I I I Glemrorrio Creek-452420121m0M I I I 25 20 15'q �1`11 10 VIA} 5 I I I I y�V Oswego Creek,in pool-45 2 1391 223 9A200 I I I 25 sensor out of WOW 15 10 c 1 1 I I Oswego Crook,near dam-452439122394600 I I 1 25 20 -- - sensor out of wee,. 15 10 c I I I a., Tryon Creek-4525211MOnti I I I 25 20 15 ti sensor out of water 10 5 1 I 1 June July August September October 2017 Source:Water temperature in tributaries,off-channel features,and main channel of the lower Willamette River,northwester Oregon,summers 2016 and 2017: USGS OFR 2018-1184,33p.by Mangano,JF,Piatt,DR,Jones,KL,and Rounds,SA(2018) Figure C.3. Temperatures of Potential Cold-Water Refugia,June 2016 to September 2016 The City actively supports the Backyard Habitat Certification Program which is a partnership between the Columbia Land Trust and the Audubon Society of Portland. The program provides site visits and advice from professionals on transforming properties into areas with native habitat. It is a very well-received program by Lake Oswego citizens and, in 2018, the City was 3rd in the region for program participation (https://create.piktochart.com/output/3160778-backyard-habitat-calendar-vear-2018). Since the City started funding the program in 2011,there have been 137.7 acres enrolled and 202 certifications totaling 45 acres certified within the City (see Figure C.4). From FY1516 to FY1819, participants representing 83 properties have planted 258 trees and 4,266 shrubs on 23 acres. The City had 55 properties participate in the program in FY1920 with 15 properties receiving certification. No properties were re-certified in FY1920. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 67 In FY1920, staff attended 10 Oswego Lake Watershed Council meetings and one Tryon Creek Watershed Council invasive removal event. s $ frI / - • ''''•-,,,. �..,J R., • • '�4 2 w, snHJ �r.rrnr^ © �� �� Imhae S FnIX� d ' f" 116 P ��'y . p ,, r g Lr nR. f �$ $19reeIN. ci8 - .1 rbe[bw Re p l^W� 4'n.. _ H„ ®�`k.k. 3 f rn .4rr`.r.rrP.J✓ v7 '}.� 1. '..6?"*. ;R rr+c r,7mn el 6'p° - € in psw°g ® r . r iRr am• mr rafANe °, w I y.^ .a� �vloe�Rw � y3 ''''',,,,ice:.: A . � 4 '' lit: W,— ae! we..rA. • dra a. — s era3 s so4-nn d " MOP • g o 5 p ,a , \ ^ t r; • CertAred • . '' ® ir 4. • Currently Uncertified ® ®® ® ° Willamette River Basin ay Ht • ® iaow se ry w NE Oego Lake Basin ` . , Lg k w� IIMI TaLlain River Basin id • See • s,. 0 0.$5 es 075 1 rn sr ��1 J�T .. . es • Figure C.4. Backyard Habitat Program Participation, FY1516 to FY1920 C.5.3 Existing Shade Protection The City uses public education on the importance of tree canopy on stream temperature through enforcement of its tree code and public education. The Planning Department reported that there were no changes in the municipal code that affected tree canopy and no code enforcement cases involving tree canopies. Historically, the City has utilized its urban forestry program and free workshops to educate the public regarding tree canopy, its effects on stream temperature, and how to keep trees healthy. This year, due to COVID-19,the free workshops were cancelled. The City was not able to install any stream crossing signs in FY1920. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 68 C.6 Adaptive Management The City is not proposing adaptive management changes for FY1920. C.7 Other Activities While the City's TMDL Implementation Plan contains the previously detailed activities, it also contains other metrics as listed in Table C.5. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 69 Table C.5. Metrics for TMDL Management of Stream Temperatures Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress In FY1920, $252,478 was used to complete public projects. From June 2015 to July 2019,the City has Implement projects that Track the amount of City spent approximately$815,400 on habitat restoration of enhance riparian areas funds expended for programs public spaces. With the FY1920 expenditures, the total Program or increase effective to preserve or expand public is $1.07M with an average of$214K spent each year Management Parks shade on City property. riparian habitat. from FY1516 to FY1920. The City funds 3 different programs associated with riparian restoration on private property.The Backyard Habitat program is a partnership with the Columbia Land Trust and the Audubon Society; the Habitat Enhancement Program (HEP) is a partnership with the three local watershed councils active in the City; and the Neighborhood Enhancement Program (NEP) is a partnership with neighborhood associations and homeowner associations. In FY1920, the City funded the Backyard Habitat Program with $38,000; the HEP with $71,522. No funds were spent on the NEP, Partner with local non- however the grants are dependent on projects profit organizations to submitted to the City and no projects were submitted support riparian habitat Track the amount of City for private riparian restoration. From July 2015 to enhancement or funds expended for programs June 2019,the City provided $282.5K to these Program protection on private to preserve or expand private programs. With the FY1920 funds, the average that Management Planning Parks property. riparian habitat. the City spends annually is$78.4K. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 70 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Report changes to the The City adopted new engineering design standards in Implement policies and Stormwater Management June 2020. Stormwater changes were primarily aimed procedures that promote Manual, Engineering Design at conveyance structures such as catchbasins and groundwater recharge or Standards, and municipal manholes. Design criteria for stormwater and UIC Post- increase base flows in code that have an effect on facilities s is generally contained in the SWMM which Construction Engineering streams. groundwater recharge. was not changed in FY1920. Track comprehensive plan Post- Monitor changes to changes and their effect on The Planning Department reported that there were no Construction Planning population density. impervious area. requests for zoning and land use changes in FY1920 Eight properties were annexed in FY1920 resulting in 8.2 additional acres. Of those 8 acres, 1.1 acres are impervious (13%). Five of the properties are zoned as R7.5 (7,500 sq ft), one property is zoned as R-10, and one is zoned as R-15. All annexed into the City to connect to the public wastewater system and 5 indicated they were interested in further development of the property. Three of the annexations were properties that already have multiple tax lots;two properties were comprised of 2 tax lots and one property was comprised of 3 tax lots. Of the lots that cannot be further subdivided, two are zoned R7.5 and Track the number of one is zoned R-10. properties annexed and zoning/land use changes from As of October 1, 2020,there are two annexation the current reporting year and applications pending. one is comprised of two tax lots Post- Monitor changes to what is anticipated for the totaling 0.42 acres and zoned as R-10. The other is Construction Planning population density. next reporting year. 0.28 acres and is assumed to be zoned R7.5. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 71 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress The target pH range was reached in all of the monitored streams. The total phosphorous target concentrations, used as a surrogate measure, were met at Ball Creek, Carter Creek, and Lost Dog Creek. Springbrook Creek and the Boones Ferry site met the winter phosphorous threshold and only exceeded the summer threshold. Springbrook Creek's winter median and geomean concentrations showed a reduction of 76% and 69% respectively,from the 1997-2003 data. The geomean at the monitored sites was less than the 460 col/100 mL target except for Nettle Creek and the summer geomean at Ball Creek. Using the summer geomean concentrations,the Collect water quality dissolved oxygen threshold was met at Ball Creek but data at the instream not at Carter Creek. The suspended solids and volatile monitoring stations Summarize water quality data suspended solids concentrations show a steady decline required in the NPDES as it relates to TMDL from the late 1990's data and meet the 50% reduction Monitoring Engineering MS4 permit. thresholds. required by the TMDL. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 72 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Lost Dog Creek Gaging Station: Discharge during Water Year 2019 (WY19) ranged from 0.01 cfs to an estimated 30 cfs. Stream temperatures ranged from 2.2°C to 19.3°C while the pH range recorded by the sonde ranged from 6.7 to 8. Dissolved oxygen concentrations measured by the EXO3 sonde ranged from 3.6mg/I to 13.9 mg/L . The only TMDL related to the parameters measured at the Lost Dog Creek station is a maximum temperature of 17.8°C. Springbrook Creek Gaging Station: Springbrook discharge recordings ranged from 0.33 cfs Collect water quality to an estimated 77 cfs in WY19.Temperatures ranged data on TMDL from 3.7°C to 18.8°C and pH ranged from 6.4 to 7.4. parameters at the Dissolved oxygen concentrations ranged from 7.4 mg/L continuous monitoring Summarize water quality data to 12.9 mg/L.. The only TMDL related to the stations required in the as it relates to TMDL parameters measured at the Lost Dog Creek station is a Monitoring Engineering NPDES MS4 permit. thresholds. maximum temperature of 17.8°C. The City maintains continuous monitoring stations at Lost Dog and Springbrook Creek. The City also Partner with other Document the status of the provided $1,990 in FY1920, in collaboration with other Clackamas co-permittees agreement with USGS and permittees and the USGS, to operate and maintain the on funding a USGS other partners on the West USGS hydrological station (14207500) on the Tualatin Monitoring Engineering gaging station. Linn USGS gaging station. River at West Linn. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 73 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress The City's water conservation program provides audits during which owners are informed about the effect of the temperature of stormwater and irrigation water on our streams and lakes after it comes into contact with warm impervious areas. Normally, staff provide the audits from May to October however, in March 2020,the program was suspended due to COVID-19 concerns. Even with the suspension, staff were able to successfully complete 18 audits including 1 audit for a large multi-family residential commercial property from July to October of 2019. The City usually holds urban forestry workshops for people which provide information about the Tree Code,tree care, and maintenance of tree canopy. Unfortunately,the urban forestry workshops were cancelled because of COVID-19 restrictions Promote public The Regional Coalition, a stormwater education education related to Track outreach efforts that group of which the City is a member, provided a urban forestry and the are related to stream booth for the local watershed councils at the Big Public Planning effect of city-wide shade temperature or canopy Float which is a celebration of the river. The float Education Engineering on stream temperature. coverage. engaged people in a salmon obstacle course. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 74 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Preserve Track the acreage of sensitive Existing Require mitigation for lands that have been There are approximately 120 acres within the City that Riparian development that affects developed and mitigation have a sensitive lands designation. Planning reported Habitat Planning sensitive lands. required for development. that 0 acres were developed in FY1920. Address Title 3 and Title Track the number of building Preserve 13 requirements that permits issued for properties Existing relate to stream buffers with sensitive lands Riparian and shade requirements delineations or that have land There were 19 building permits issued that either Habitat Planning along waterways. within 50ft of a waterway. affected sensitive lands or were within 50 ft of streams. Address Title 3 and Title Track the number of land use Preserve 13 requirements that applications for properties Existing relate to stream buffers with sensitive lands Riparian Planning and shade requirements delineations or that have land There were 19 land-use applications that either Habitat Engineering along waterways. within 50ft of a waterway. affected sensitive lands or were within 50ft of streams. Address Title 3 and Title Preserve 13 requirements that Track modifications to stream Existing relate to stream buffers buffers including the net Riparian and shade requirements acreage lost or gained from Planning reported that no delineations resulted in loss Habitat Planning along waterways. the delineations. or increases in riparian buffers City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 75 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress When new LiDAR data is available: Estimate change in effective shade relative to adoption of Sensitive Lands revision and based on Address Title 3 and Title development activity. Preserve 13 requirements that Compare expected change Existing relate to stream buffers with the actual change as Riparian and shade requirements shown by the use of LiDAR LiDAR was flown in Summer 2019, however it was not Habitat Engineering along waterways. and multi-spectral imagery. available for use by the City until Summer 2020. Address Title 3 and Title Preserve 13 requirements that Track modifications to the Existing relate to stream buffers municipal code and other Planning reported that no modifications to the Riparian Engineering and shade requirements planning documents as they municipal code and other planning documents affected Habitat Planning along waterways. relate to stream temperature. stream temperatures. Address Title 3 and Title Preserve 13 requirements that Track the number of Existing relate to stream buffers municipal code violations that Riparian and shade requirements affect sensitive lands or areas There were 2 investigations of sensitive lands Habitat Planning along waterways. within 50ft of a waterway. violations. Neither resulted in a citation. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 76 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Two capital improvements projects addressed sources of hydromodification in FY1920. The Lakeview Blvd Realignment project had a large raingarden constructed to treat and detain stormwater from approximately 0.28 acres of previously-untreated impervious area. The D Avenue project treated 3.34 acres of previously-untreated impervious area by constructing 12 swales and 27 raingardens; the facilities also reduce stormwater volume to Tryon Creek. In addition,the project reduced the number of outfalls and rerouted the outfall to a lower section of the creek thereby reducing the length of stream affected by hydromodification from the City's Address Title 3 and Title Track the number of projects stormwater. In FY2021,the Wembley Park Road Preserve 13 requirements that that address project will include the construction of treatment Existing relate to stream buffers hydromodification (see 2016 facilities (primarily Contech StormFilters) and the Riparian and shade requirements Hydromodification reconstruction of several outfalls to enhance energy Habitat Engineering along waterways. Assessment). dissipation and reduce streambank erosion. Preserve There are almost 370 acres under active restoration Existing Actively restore and Track the acreage under through the Parks Department. It is expected that Riparian maintain public riparian active restoration. Track the some of this acreage will transition to monitoring Habitat Parks habitat. acreage being maintained. status in FY2021. Increase Address Title 3 and Title Existing Shade 13 requirements that Track the number of and Improve relate to stream buffers municipal code violations Existing and shade requirements that affect tree canopy in the There were no instances of enforcement cases that Habitat Planning along waterways. City. affected tree canopy. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 77 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Evaluate the amount of Increase Address Title 3 and Title effective shade provided by Existing Shade 13 requirements that riparian protections in and Improve relate to stream buffers relation to TMDL target in the Existing and shade requirements City's TMDL Implementation The new LiDAR was flown in Summer 2019, however it Habitat Engineering along waterways. Plan. was not available to the City until Summer 2020. The City worked with the USGS, City of Wilsonville, Meyer Memorial Trust, and Benton County Soil and Water Conservation District to map cold-water refugia (CWR) along the mainstem of the Willamette River. Four sites within the City's jurisdiction were monitored for water temperature: Tryon Creek, Oswego Creek, Glenmorrie Dr seep, and Arbor Creek seep. Two sites, Tryon Creek and the seep at Glenmorrie Dr, showed some promise as cold-water refugia with temperatures between 15 and 17° C from June to mid-September. The seep at Arbor Creek, while somewhat cooler than the Willamette River, neared or exceeded 20°C several times between June and mid-September. Oswego Develop implementation Creek did not provide consistent temperature Increase strategy (including funding, recordings, however the temperatures that were Existing Shade property acquisition, and recorded showed temperatures that were consistently and Improve Create, Enhance, or design concept)for near or exceeding 20°C. Because seeps, by definition, Existing Protect Cold Water preserving, enhancing or do not provide a large volume of water,the City's best Habitat Engineering Refugia. creating cold water refugia. area for protecting CWR is Tryon Creek. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 78 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Increase Track the number of projects Existing Shade identified and constructed (or and Improve Create, Enhance, or in design phase)that Existing Protect Cold Water preserve, enhance or create No projects were completed in FY1920 to specifically Habitat Engineering Refugia. cold water refugia. preserve, enhance, or protect these areas. Increase Existing Shade Implement projects that There were no changes made to the Habitat and Improve enhance riparian areas Track changes to the HEP Enhancement Program's application process nor to the Existing or increase effective application process or prioritization criteria used to determine funding of Habitat Parks shade on City property. prioritization. projects. Increase Track changes or Existing Shade Implement projects that implementation steps to Parks The Iron Mountain and Woodmont Master Plans have and Improve enhance riparian areas Master Plans that relate to been approved and are expected to be constructed in Existing or increase effective riparian protection or 2020. Habitat Parks shade on City property. effective shade. Partner with local non- Historically, the City has had great success with the Increase profit organizations to Backyard Habitat Program even winning an award in Existing Shade support riparian habitat 2018 for its participation rate. The City had 55 and Improve enhancement or Track the number of properties participate in the program in FY1920 with 15 Existing protection on private properties participating in the properties receiving certification. No properties were Habitat Planning property. Backyard Habitat Program. re-certified. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 79 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Historically, the City has had great success with the Backyard Habitat Program even winning an award in Partner with local non- 2018 for its participation rate. The City had 55 Increase profit organizations to Track the number of properties participate in the program in FY1920 with 15 Existing Shade support riparian habitat properties participating in the properties receiving certification. No properties were and Improve enhancement or Backyard Habitat Program re-certified. Therefore, no properties within an RP/RC Existing protection on private that have sensitive lands or overlay or within 50 ft of a waterway were certified by Habitat Planning property. are within 50ft of a waterway. the program. Historically, the City increases shade on private property through the HEP and Backyard Habitat programs and through NEP grants. In FY1920, no projects were submitted through the NEP that were restoration-oriented. There were 15 properties that received certification in the Backyard Habitat program in FY1920. From 2015 to 2020, the City provided funds through the HEP to restore approximately 24 acres through removing invasive plants and installing approximately 4,200 trees and shrubs.Through the Partner with local non- NEP process and its partnership with the Columbia Increase profit organizations to Track the acreage (or the Land Trust and Audubon Society of Portland's Existing Shade support riparian habitat number of trees and shrubs Backyard Habitat Certification program,the City has and Improve enhancement or planted) with increased shade assisted in restoring the riparian habitat of Existing Planning protection on private due to City partnerships or properties with a total acreage of 40 acres. Not all of Habitat Parks property. incentives. the acreage in each property was riparian habitat. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 80 Best Management Responsible Practice Department Measurable Goal Tracking Rubric FY1920 Progress Partner with local non- Increase profit organizations to Existing Shade support riparian habitat Track the amount of funds and Improve enhancement or expended for riparian habitat In FY1920,the City disbursed $71,522 for private Existing Planning protection on private enhancement or protection projects and $252,478 for public projects through its Habitat Parks property. on private property. Habitat Enhancement Program. Partner with local non- Track the number of meetings Staff attended ten Oswego Lake Watershed Council Increase profit organizations to or events sponsored by non- (OLWC) meetings. Staff attended one TCWC- Existing Shade support riparian habitat profit groups that were sponsored invasive removal events. Staff reviewed and Improve enhancement or attended by staff. Track Habitat Enhancement Project applications and Existing protection on private whether technical expertise provided technical expertise for all three watershed Habitat Engineering property. was provided. councils. City of Lake Oswego_MS4 and TMDL Annual Report, FY1920 Page 81 400 Inw LAKE 0SWECO he althdy w ter he Stewardship fora Sustainable Future THE RIVER STARTS HERE