Agenda - Public Works Committee - 09/16/2008

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CASE# CQNS~DER WELLT3E.AD FR(~TECTxQN IiY1~"LEMENT.ATIQ-1'~i ACTIQN ~'R,QGRAM ~y: Steven Jankowsl~i, City Engineer Backgxc~und: The. City of Ramsey is required to prepare a wellhead protection plan for .the purpose of safeguarding areas which recharge"aquifers from .which the .City draws its municipal water supply. The Engineering Department is preparing this plan with the assistance of the Community Development Department. It is scheduled to be submitted to the Minnesota Department of Health at the end of September.. The purpose of this case is to present a brief overview of the contents of the plan and to review the slate of possible implementation action elements suggested by the Department of Health for aquifers having a moderately vulnerable rating. The City of Ramsey produces all of its municipal .water supply from eight wells located within two separate well fields. Wells l & 2 are located within the :East well Field which has been designated as having low vulnerability to contamination due to factors which include. goad ;geologic protection; documentation of sound well construction; and the lacy of any sustained water quality issues. Wells 3 through 8 are lacated in the West well field which has been designated as having. moderate vulnerability to contamination due to factors which include. the possibility that water may be recharging via vertical leakage from the sand and gravel aquifer above; the presence of tritium suggesting that the groundwater is relatively. young; and that there is a lack of clay overlying the bedrock at Well S. Attached to this case are two figures illustrating the following elements in each well field: • Municipal well locations • The emergency management zone -the innermost' circle around each well were stringent separation distances to potential contaminants should be maintained. • The well head protection area (WHPA) • the next outer ring around each well that represents the extent of the area from which groundwater would travel to the well withini a 10 year period at projected pumping rates. • The .Drinking Water Supply Management .Area (DWSMA) -the outermost line designated an the map which follows recognizable boundaries. This is the area within which wellhead protection activities are to be implemented. to safeguard the wells. from contamination, fJbservationsc The City's wellhead protection plan is to be tailored to its vulnerability classifications. Contamination threats to low and moderately vulnerable aquifers such as Ramsey's include; other wells; underground or above ground storage tanks, shallow disposal-type wells; and high 105