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Agenda Item - 2022-01-04 - Number 7.1 - Public Testimony - Mark Heizer 7.1 To: City of Lake Oswego, City Council. Attention Kari Linder, City Recorder Regarding LU 20-0005 Citvrecorder@lakeoswego.city From Mark Heizer, Resident. 18345 Heather Ann Ct. Lake Oswego, OR 97034 Mark.r.heizer@gmail.com 503.333.9854 I wish to present testimony to the Lake Oswego Planning Commission meeting of Tuesday,January 4, 2022, regarding the adoption of updates to the flood plain ordinances, September 27, 2021.The following information was presented to the Lake Oswego Planning Commission on September 27, 2021. During that meeting,the City Staff, including the current flood plain administrator, noted that the included information was correct and was not disputed by Staff. I will note specific feedback from the Planning Commission later and any items that are underlined within are additional notes to the testimony provided to the Planning Commission. I would like to thank the Council for the opportunity to present this evening. My reason for coming to the Council is to request that before the City Council moves forward with new regulations regarding flood plain administration in the City,the City should have complete and accurate flood plain maps. Property owners in the flood plain along the Oswego Canal have flood plain lines that are up to 3 feet (or more) higher than these should have. I wish to submit the included information regarding significant errors in the City's Figure 50.05.011-A: Flood Management Area Map A. Testimony and documentation. My desire is to ask the City to be sure that the flood maps are correct and accurate before moving forward with updates with new city codes and ordinances. Nearly 100 property owners adjacent to the Oswego Canal are currently affected by Flood maps that are in error. As noted during my testimony to the Planning Commission on September 17. 2021,the City Flood Plain administrator acknowledged that the current flood plain map for these property owners is inaccurate. Therefore, I'm requesting the City come into compliance with its own City Code. Section 50.05.11, Part 4, Map Administration, subpart b. Map Error.The LO city code reads: "Within 90 days of receiving information establishing a possible error in the existence or location of a flood management area,the City Manager shall provide notice of a public hearing at which the Planning Commission will review the error for compliance with this section. Notice of the hearing shall be sent to property owners who have property that will be included or withdrawn from the flood management area as a result of the change. Notice shall also be sent to owners of property within 100 ft. of the affected properties. Following the public hearing, the Planning Commission shall make a recommendation to the City Council as to whether the flood management area boundaries should be changed." On September 27,The Planning Commission assured me that they would bring this issue to the attention of the City Council. Whv? Because they were presented with undisputed evidence that the current flood plain maps are not iust "possibly" in error, but that some portions of the maps are significantly in error.At the Southshore Bridge, there is over a 3-foot elevation error that can affect the elevation southward along the canal past the Bryant Street bridge. The City should take this seriously: Many property owners could be removed from the flood plain. Even more property owners could see greater use of their property restored: portions of their land will be unusable under the new code without an adiustment. Replacing an air conditioning unit can be affected by the flood plain line.Those of us paving flood insurance iust had an 18% increase in our flood insurance costs. And this 18% increase will be repeated every year for the next 5 years. The adiustment of the FEMA map for the main lake in 2012 helped the residents along the lake. Sadly, the residents along and adiacent to the canal were left behind. City staff has been aware of this error for well over 5 years. It's time for the City to follow its own code, hold the hearing and correct the map. The remainder of my presentation outlines the three maior adiustments not included in the current flood analysis. If you have any questions, I'd be happy to answer them.Thank you for your consideration. There are three reasons the map is inaccurate, some with significant impact on flow through the canal. These errors likely are placing many properties within a flood zone that should not be in a flood zone (either partially or wholly).This affects their use and property values. First, when the flood elevations for the main lake were revised with FEMA in August, 2012,the base flood elevation of the main lake elevation dropped from 106.6 feet to 103.2 feet.The issue arises where the Oswego Canal empties into the main lake (highlighted in Figure 1 from current LO maps). See Figure 2 for current FEMA profiles, Location "A" is the intersection of the canal and the lake. FIGURE 1 itis " 9'5 > Ir/ . AA i1 /sv G `' �r vtrit �_- Ito ; elket1 f �' 4 LAKEVIEW REGREAT,DNobi, i'//////// Lir-4,144,146, � � ; :is , w. West Bay ,.. : -. ;.. miliCI a� Lake Base Flood -11k4i .m . `60 SHORE siT ,P°C, i tr) ' 4-414''' ' +¢11;111 !e itel i!� Elevation: 103.2' falta ] gj ;) °G� _' ' `� NGVD'88 / *ROAD a L �cr`�� t 'be ...-;? 0 a a Ili , fitigti 4. 41' YlRGiN1A WAY o a 1Q 4 -,74 . } ''' .T1 t:11V111 T ±,- 15 E;11-g-1 t t'-itir -LIADII C317151 //sr "--, -filiplr. .., .,,V.M;1141.1 )*IN,C71-, 1 FIGURE 2 1611431313 aus F7 77I MOM= KR735 SUR KL-71. RA AT7:117 ME IROLEMT rQx=aus sir Vil...:- ��.__�,..`.� Dos<Ta rpm& • irRT: iY�2Fri pI weer IlL ..........parr WOW rat !Oat!, I* 637 125 941 4 s1 106.3 106.3 1063 0.0 731 136 934 6 106 6 106,E 0 0 C 1365 74 591 102 10E.« 1012 1052 0.0 D 1540 75 053 9-4 109.1 109-1 1093 0-1 E 10'3 67 067 9.0 1109 1109 110.4 0.0 F 230 64 665 91 111.3 111.3 111.3 0.0 G 28J0 95 1007 7.3 112.3 133 112.9 0.6 13 1150 8a 9'5 72 112.9 LW 113.4 0-5 1 3400 90 1037 66 1133 113-1 113.E 0-5 I 3971 156 DI 16 115.5 135.5 115.9 0.4 A 4030 155 1354 66 116.6 1166 116.7 0.1 L 4391 92 916 7.1 116.1 1161 116.9 0-1 hi 4562 97 1042 67 117.4 117.4 117.6 09 N 4912 105 1116 6.1 119.5 11115 119.E 0.3 O 5413 231 2047 3 2 1194 119.4 1300 0.6 P 5707 347 as6 3 7 119.5 1103 120.4 0.9 Q 5950 373 2 06 /0 110.7 114-7 1X.5 00 R 642 391 2 557 17 124.1 L10.1 120.9 0.1 5 7207 04 S97 3 2 1210 121.0 121,E 0 0 T 7465 94 9C0 3.2 131.5 121.6 122.E 1.0 L: 7747 :0 905 11 11.1.6 121.11 113.6 1-0 V 6533 56 039 3.5 123.5 1313 123.3 0.0 `Sr=dewar itif rI ebme lie Omega FEDERAL E4ERGENC'M4M.GE!NT,AGENCY FLOODWAY DATA i CLACKAMAS COUNTY. OR u ANC)INCORPORATED AREAS OSWEGO CANAL At the entry to the lake, point A,you can see that the base 1%flood elevation is 106.3 feet.This 3-foot elevation difference is important. It represents 3 extra feet in depth across the 125-foot wide channel.At 6-feet per second flow rate,this location can allow an additional 2,250 cubic feet per second of flow (CFS) out of the canal. This more water can flow out of the canal and less water can back up into the canal. See Figure 3 for the red arrow pointing to the 1% flood elevation at point A(107 ft), with the green arrow pointing to the 2%flood line, which is 103-feet at the lake entry point A. 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Ylr:■■■M■■■■w■ —,Y.r.ragr.a tiom � allr`•RR�� ■■ Y rg r■R ■■ ■�F .• I A■ g ■a■n■ii■ • Y■uu■ iii:;■9 rum ■ - .. mil— dim ■■ .u■11:3 ■ ■ - ,••ILIIIW 11u■uYr.■lu■a■ :::V. ■u■ I ■ C?coi ■■■• r r-: 0 *• 11 W M 2 COD MIN--_ talW . IJWI"-47 -11 l,U6G 1gOYQ 11 707 - - — tillAb(I4taMCI 41 rEYr 56P The second big effect was the modification of the canal inlet structure.This took place after the current FEMA data was established (Figures 2 and 3). Per data available, restoration of the structure potentially reduced flow at the canal inlet channel by 300 CFS.This needs verification and should be included in a revised hydrology study. I recognize that most floodwater enters through the Rivergrove channel, but this still has an effect. Finally, the third reduction is relative to the dredging of the canal in 2010 as part of a sewer project. Available reports show that 50,000 cubic yards (over 1 million cubic feet) of material was removed between the Bryant Bridge and the Southshore Bridge.This increased the channel depth and flow capacity further. Combined,these do have a substantive effect and can reshape the flood map for over 100 properties.These citizens deserve to know whether their properties still fall in the flood plain. Not just lakefront property owners should benefit from the revised weir on the lake dam. Bad maps should not reduce the value of properties. In 2015, I spoke with Rob Amsberry, the City's Flood Plain Administrator. While helpful in answering questions, he could not answer why the City had not requested an LOMR for the Canal. He agreed that during a 1%flood event,the canal won't magically drop 4-feet when it reaches the south shore bridge. But he noted that it would take a request from City Council to get their office to move forward. So, I am here today to make the City aware of a significant map error and that your own city regulations require an inquiry. I strongly encourage the city to update the flow hydrology and request a FEMA update,just as was done for the residents and businesses along the lake. In 2015, I also spoke with Seth Jelen,the hydrologist/expert who performed the 2008 and 2012 report on the Tualatin, Canal and Lake flood elevations. If Lake Corp has enough information on the dredging of the canal, it is easy for him to include the additional flow area into the calculations (a computer simulation). It may take some surveying to get the figures otherwise. Additional figures: Figure 4: During the FEMA re-mapping,the lake map at Blue Herron Canal was updated as far as the middle of Bryant Road. But the south side of Bryant was covered by the Canal Flood map. Current Map A shows that flood water will flow to the middle of Bryant Road and stop, even though the slope is downhill toward Cardinal Drive. FIGURE 4 zmi Alifit 5 /7sa0 <00044=-7fir•jcwir,90.5, 2 416P,:_o_.2. NV 4000...409 G R NY kt :k ; il ON J 7,90 9 ., 4.441 44;410111 VJ:€5/ INI f AV 4k1,0 lit. �• Ophirtiggithri. I °' 18308 ]8}66 1 3 5 t. .4 E J :!,' i II- Q Canal Inlet before and after ' 'te s " Y ' .► 1� R{ s4' 'r. _...: ,.t,., . 11, This work reduces overflow at the canal inlet.