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

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Understanding of the Project Our team is deeply familiar with your local conditions and needs, based on previous experience completing the source water analysis for the City in 2021. The following section details our knowledge of your unique circumstances, challenges, and potential solutions. The City of Ramsey operates eight wells in the Tunnel City-Wonewoc aquifer. Six wells feed the 10-million-gallon- per-day (MGD) water treatment plant. Summer demand passes 5 MGD. The 2040 maximum day demand is 10.3 MGD. Firm well capacity is 8.3 MGD. Wells #9 and #10 will fill remaining water demand. The City needs a Well Siting Assessment before April 2027. The assessment has two phases: o Phase 1 (Tasks 1 to 7): Desktop study, recommend two to four sites, compare treatment options, and submit the MnDNR Preliminary Well Construction Assessment o Phase 2 (Tasks 8 to 13): Drill and test four test wells, analyze the results, and recommend the well design Wells #9 and #10 are planned for construction in 2027. The test wells must confirm water quantity and quality at the chosen sites before final design starts. Final well design and construction services are outside this RFP. WHAT WE ALREADY KNOW SEH already reviewed publications and mapped the source aquifer for the City in 2021. Key findings that guide this project include the following: o The Tunnel City Group is the uppermost bedrock across most of the City. The Wonewoc Sandstone below it is the more productive unit. o Existing wells are 316 to 390 feet deep with 191 to 282 feet of casing. Wells experience 60 to 120 feet of drawdown pumping between 500 to 1,000 gallons per minute (gpm). o Pumping Well 7 at 800 gpm produced 6 to 9 feet of drawdown at Well 8, 2,400 feet away. Transmissivity from that test is about 11,500 gpd/ft. o The 2021 model shows 30 to 40 feet of drawdown 1,500 feet from the wellfield on a present-day peak day. Drawdown nearly doubles under 2040 demand. o New wells should be at least 1,500 to 2,000 feet from existing wells. o Four of eight wells exceed the MDH manganese health -based value of 0.100 mg/L. New wells will likely need treatment. rit The 2021 study, completed by SEH for the City of Ramsey, mapped the Tunnel City aquifer thickness. 1531. 142. 130. 04360 700551 6.4301 316301 3.10353 3aoa F ; tej Tunnel City Thickness Source Water Fnalyels Cry in Ramoey Minnesota SEH Figure 6 ■ • The 2021 study, completed by SEH for the City of Ramsey, mapped the Wonewoc aquifer thickness. 120.307 100.3 03.5710 00.037 40 1022 13 3075 510352.05 A Wonewoc Thickness SEH City of Ramsey Minnesota Figure 6 SHORT ELLIOTT HENDRICKSON INC. WELL SITING ASSESSMENT FOR MUNICIPAL WELLS #9 AND #10