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Edmonds Civic Center Groundwater Monitoring Memorandum 9.4.2020 (2)BLD2019-1590 RESU B LANDAU Nov 04 2020 CITY OF EDMONDS ASSOCIATE D PARTMENRVICES September 4, 2020 Walker Macy 111 SW Oak St, Suite 200 Portland, OR 97204 Attn: Ms. Andrea Kuns, ASLA, Senior Associate Transmitted via email to: akuns@WalkerMacy.com Re: Summary of Wet Season Groundwater Monitoring Civic Center Playfield Improvements Edmonds, Washington LAI Project No. 1548002.010.011 Dear Ms. Kuns: This memorandum summarizes the results of groundwater monitoring completed by Landau Associates, Inc. (LAI) in support of the Civic Center Playfield Improvements project, located at 598 Edmonds Street in Edmonds, Washington (site; Figure 1). Project Understanding LAI's project understanding is based on information provided by the City of Edmonds (City; project owner) and Walker Macy (project architect). The City plans to improve the existing Civic Center Playfield by adding a restroom and concession building, a shade pavilion, athletic courts and field, a water feature, a playground, a skate park, a scramble wall, view terraces, walkways, and stormwater infiltration facilities. To facilitate design of the proposed stormwater management systems, LAI monitored groundwater elevations at the site during the 2018-2020 wet seasons. Services were provided in accordance with the scope outlined in the Standard Form of Agreement between Architect (Walker Macy) and Consultant (LAI), dated April 24, 2017. Groundwater Observations During an earlier phase of the project, LAI installed monitoring wells in borings B-5 and B-6. The approximate locations of the borings are shown on Figure 2. LAI installed Solinst° leveloggers in both monitoring wells to measure and log semi -continuous groundwater levels at the site. Additionally, a Solinst barologger was installed in a dry, sheltered area of the site to measure and log changes in atmospheric pressure. Barologger data were used to compensate the water and 130 2nd Avenue South • Edmonds, Washington 98020 • (425) 778-0907 • www.landauinc.com Civic Center Playfield Improvements RESUB Landau AssociateNov 04 2020 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT atmospheric pressure measurements recorded by the leveloggers. The compensated water pressure measurements were then converted to water level -equivalent measurements. Site groundwater levels were initially logged between October 24, 2018 and March 19, 2019. Subsequently, groundwater levels were logged between September 30, 2019 and May 4, 2020. An equipment malfunction during the 2018-2019 wet season resulted in an incomplete set of groundwater data. LAI replaced the leveloggers and barologger before the 2019-2020 wet season. During the 2019-2020 wet season, the leveloggers measured and logged groundwater levels at 2- hour intervals. Between late September 2019 and early May 2020, LAI personnel manually measured groundwater levels on or around the first of each month. LAI's manual water -level measurements for the 2019-2020 wet season are presented in the following table. The compensated water levels are presented on Figure 3 along with precipitation data from the National Oceanic and Atmospheric Administration Weather Forecast Office Seattle Station. Depth to Groundwater (ft bgs) Location of Manual 9/30/2019 11/1/2019 12/2/2019 1/2/2020 2/3/2020 3/3/2020 3/31/2020 5/4/2020 Reading B-5 4.2 4 3.8 3 3 2.9 3.1 3.36 B-6 2.8 3.75 2.8 2.5 2.75 3 3 3.09 bgs = below ground surface ft = feet Use of This Memorandum Landau Associates has prepared this wet season groundwater monitoring memorandum for the exclusive use of Walker Macy and the City of Edmonds for specific application to the Civic Center Playfield Improvements project in Edmonds, Washington. No other party is entitled to rely on the information, conclusions, and recommendations included in this document without the express written consent of Landau Associates. Reuse of the information, conclusions, and recommendations provided herein for extensions of the project or for any other project, without review and authorization by Landau Associates, shall be at the user's sole risk. Landau Associates warrants that, within the limitations of scope, schedule, and budget, its services have been provided in a manner consistent with that level of care and skil I ordinarily exercised by members of the profession currently practicing in the same locality under similar conditions as this project. Landau Associates makes no other warranty, either express or implied. September 4, 2020 2 Civic Center Playfield Improvements RESUB LandauAssociate9VOV 04 2020 — CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT Closing If you have questions, or if additional information is required, please contact the undersigned at (425) 329-0251. LANDAU ASSOCIATES, INC. Sean M. Gertz, PE Senior Project Engineer sy� w�4 Steven R. Wright, PE Principal BCS/SMG/SZW/mcs [P:\1548\002\R\GROUNDWATER MONITORING MEMO\EDMONDS CIVIC CENTER GROUNDWATER MONITORING MEMORANDUM 9.4.2020.DOCX] Attachments: Figure 1. Vicinity Map Figure 2. Site and Exploration Plan Figure 3. Groundwater Level Readings: September 2019—May 2020 September 4, 2020 3 Puget Sound I Gaspers St� Project Location = > a Mta ��P I P,F t ♦+ ON Main St I I N 0 0.5 1 Miles Data Source: Esri 2012 Civic Center LANDAU Playfield Improvements ASSOCIATES Edmonds, Washington l RESUB NOTM 2020 rD�vVCFIITY OF E MONDS Snoho nyfifELOPMEN SERVICES DEPART ENT County Park f . Esperance ti i Seattle Spokane Tacoma Ilympia Washington Vicinity Map Figure 1 RESUB OH— OHS OH - I I q I . I ----------------------------� 2020 CI+Y OF ED ONDS EVE40PMEN SERVICES DEPART ENT I I I I j I Jww Q I Legend B-1 Boring Location and Designation TP-1 Test Pit Location and Designation Basemap source: KPFF Land Surve) Civic Center LANDAU Playfield Improvements ASSOCIATES Edmonds, Washington Bell —._._._.—.—.... { 0 150 300 Scale in Feet rs September 2017 Figure Site & Exploration Plan 2 RESUB Nov 04 2020 0 14/4U rreUrnUaraU I rprojeas\ 1046rUU4nMuruunuwaler rvronuonny vieuiwrua 4u i a - 4u4u vvv Uara.000X DEVELOPMENT SERVICES DEPARTMENT N C, I F N N N N N l0 F-' O O FA A \ O \ \ \ F-� \ \ \ IVl IV \ \ \ F-� \ \ \ I� \ \ \ W W \ \ \ A \ \ \ (/1 W \ I--' fV 00 \ I--' 00 r1jUn \ \ I--' W W \ W 0 fJ \ 0 I--' fJ \ \ I--' W W \ W 0 -4 \ O V A I--� 00 A F-� 00 U'I fV lD Ol W O Ol W O V W O V A fJ l0 Ol W O Ol W O V A \ \ \ \ \ III\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O ILD W W ILD LID W W W LD W ILD W W W 0 0 CD r1jC fv fv fv fv fv fJ fJ Ili0 0 0 0 0 CD CD lO lO lO lO � lD lD lD l0 lD lD lD lD lD O O O O O O O O O O O O O O O O O O 0.0 6 5.5 too 2.0 5LO � L 4.5 4.0 4 •� 3.5 i 6.0 3 fV 0 2.5 0 8.0 2 1.5 I? 0 10.0 1 0.5 I 12.0 0 13-5 Water Level B-6 Water Level Rainfall Notes 1) Water level data were collected from monitoring wells installed in borings B-5 and B-6 and have been converted to depth -to - water, relative to ground surface. 2) Precipitation data are from the National Oceanic and Atmospheric Administration Weather Forecast Office Seattle Station. Civic Center Playfield Improvements Groundwater Level Readings: Figure LANDAU Edmonds, Washington September 2019—May 2020 3 ASSOCIATES W_ -IV