Agenda - Council - 10/08/2019 - Laserfiche WebLink

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Introduction This summary documents the amended delineation of the wellhead protection area (WHPA), drinking water supply management area (DWSMA), emergency response area (ERA), and the vulnerability assessments for the city of Ramsey's drinking water supply wells and DWSMA (PWSID 1020035). These were initially prepared in September of 2007 and must now be amended as the public water supply's wellhead plan has nearly expired. Protection Area Boundaries The city of Ramsey's DWSMA is unchanged (Figures 1a and lb). The amount of water pumped by the city's wells has decreased since the previous WHPA delineations. However, the well interference along with the change in pumping configuration has warranted the delineation of an updated WHPA. The WHPA still represent a 10-year time of travel. Vulnerability Assessments and Management Implications Both the western field (Wells 3, 4, 5, 6, 7, and 8) and the eastern field (Wells 1 and 2) are considered to be vulnerable. While there is no change in vulnerability status for the western DWSMA, the rising tritium in Well #1 argues for a more protective DWSMA vulnerability rating. Therefore, the DWSMA vulnerability status around Wells 1 and 2 changed from low to moderate. The aquifer used by the city of Ramsey wells has some level of geologic protection, with areas of moderate vulnerability. The primary threats are other wells that penetrate the city's aquifer, as well as large capacity above and below ground chemical storage tanks. The remainder of the city's wellhead protection plan will outline strategies for effectively managing contaminant sources within the DWSMA. Documentation MDH rule criteria and guidelines were used to assess the adequacy of the existing delineations and vulnerability assessments and evaluate the impact of newer data. The results of this assessment showed that a full update of the Part 1 plan is not necessary and instead this brief synopsis is adequate to amend the Part 1 plan. The documentation of this assessment is available from MDH upon request.