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

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Potential contaminant source locations were verified, to the extent possible, during preparation of this Plan amendment (Table C-3 through Table C-8). Verification procedures used included matching mapped locations with addresses on MDH Well Records or State/County-issued permits or in County/State/Federal databases, published business addresses, property parcel addresses, local knowledge of City staff, or information from City files (note that not all verification procedures were used for each type of potential contaminant source). The data tables indicate the status of verification for each potential contaminant source location. New information developed on contaminant sources in the future will be verified as they are discovered as part of the WHPP implementation. C.1.2.1.1.1 Wells Wells located within the City's DWSMAs, in particular wells completed in or penetrating a source water aquifer (i.e., an aquifer from which the City's wells pump water), have the potential to be a pathway via which contamination could more rapidly reach the source water aquifer and the Ramsey municipal water supply wells; especially if the wells were not properly installed or have not been adequately maintained. Data obtained from the Minnesota County Well Index (CWI) during the PCSI indicates that there are 216 wells (this number does not include the eight Ramsey municipal wells) within the Ramsey DWSMAs (Figure C-5). Two hundred fourteen of these wells are identified as active. The status of the other two wells is unknown. Table C-3 lists the wells that were identified in the DWSMAs and indicates the aquifer in which each well is completed (if known), the date the well was completed (if known), and the status of the well (if known). During the review of wells in the DWSMAs during the PCSI, 102 sealed wells were identified. Per the April 4, 2019 Scoping 2 Decision Notice, the sealed well locations are not included in the PCSI. However, since an improperly sealed well could act as a pathway for contaminants to migrate from the surface into the groundwater system the City believes it is important to maintain a record of sealed well locations. Therefore, sealed well locations in the DWSMAs are shown in Attachment C-2. As indicated in Table C-3, uses for the wells in the DWSMAs that are known to be active (not including the City's water supply wells) include domestic (173), non -community public water supply (either transient or non -transient) (8), elevator (4), irrigation (2), commercial (2), industrial (1), test well (2), and monitor well (1). Eighty-five of these active wells are completed in or penetrate the source water aquifer. The aquifer in which 36 of the active wells are open is not available (i.e., not identified in the public database). In addition, the aquifer in which one of the unknown status wells is open is not available. Wells located within the DWSMAs, particularly those wells completed in or below the source water aquifer, have the potential for being a pathway for contamination to reach the source water aquifer and the Ramsey municipal water supply wells. Available information from the Minnesota Department of Natural Resources' (MDNR) Minnesota Permitting and Reporting System (MPARS) database and the CWI was reviewed to identify active high capacity wells within a zone that includes the DWSMAs and extends one mile beyond the boundaries of the DWSMAs. The available information indicates there are 31 active high capacity well within the zone of interest in addition to the eight Ramsey municipal water supply wells. The high capacity well locations are shown on Figure C-11. High capacity wells are defined as wells that pump more than 1,000,000 gallons C-4