Agenda - Council - 10/27/2026 - Laserfiche WebLink

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Workplan/Schedule The following work plan outlines a clear path, from data collection to drilling oversight and final reporting. Knowledge gained during the City's 2021 source water study provides valuable context that will help streamline the evaluation process and identify potential constraints early. Combined with SEH's disciplined project management approach, this allows us to deliver timely results while maintaining project momentum. Phase 1: Desktop Study TASK 0 DESKTOP HYDROGEOLOGIC EVALUATION SEH will build on the source water analysis we completed for the City in 2021. That work mapped the thickness and extent of the Tunnel City Group and the Wonewoc Sandstone across the City, calculated aquifer parameters from City well records, and built a Metro Model 3 submodel of the wellfield. For this task SEH will update that work with data published since 2021 and with the City's current operating records. SEH will: o Compile well construction records, geologic logs, and aquifer test data from the Minnesota Well Index for relevant wells within and near the City limits, and add wells drilled since 2021 o Review the Anoka County Geologic Atlas (Parts A and B), Minnesota Geological Survey bedrock topography and depth -to -bedrock mapping, and MnDNR county well index interpretations for the Tunnel City- Wonewoc aquifer o Update if new information is available from publications the isopach and siruc;ture contour maps for the top of bedrock, the Tunnel City Group, and the Wonewoc Sandstone, and map the depth to the Eau Claire Formation, which is the regulated confining layer that limits well depth o Compile MnDNR observation well records and the City's water appropriation reporting to define seasonal water level trends and current use o Compile water chemistry for City wells and nearby wells, including iron, rIIarlese, hardness, nitrate, and any PFAS results, to define expected raw water quality by area — Since 2021, MPCA has published the groundwater contamination atlas which shows select contaminants from monitoring wells across the state, including nearby PFAS results, which could be useful in selecting a well site V Deliverables: Updated figures for aquifer thickness, structure, potentiometric surface, and water quality, with a summary of aquifer parameters by well. TASK ® RECOMMEND TWO TO FOUR WELL SITES SEH will screen the three general areas identified in the 2021 study (Areas A, B, and C) and any new sites identified in Task 1 in reference to City -owned parcels outside those areas. The screening process will include the following: o Rank each candidate area on aquifer thickness and expected yield, depth to bedrock, distance from existing City wells, and distance to the existing watermain and the water treatment plant o Review Minnesota Department of Health (MDH) isolation distances from Minnesota Rules 4725 for public water supply wells, including setbacks from sewers, septic systems, storage tanks, and other contaminant sources o Complete a desktop review of MPCA and MDH databases and the City's wellhead protection records for potential contaminant sources near each candidate site o Confirm parcel ownership, zoning, site access for a drill rig, and approximate space for a future pump house and pitless unit o Meet with City staff to review the screening results and confirm which parcels are available for drilling V Deliverables: Site screening matrix, site map, and a ranked list of two to four recommended sites with proposed test hole and test well locations. SHORT ELLIOTT HENDRICKSON INC. WELL SITING ASSESSMENT FOR MUNICIPAL WELLS #9 AND #10