Agenda - Council - 11/07/2005 - Laserfiche WebLink

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CASE (7()NSII)ER RIVER BANK WATER SUPPLY COLLECTION SYSTEM PILOT STUDY By: Leonard Linton, Civil Engineer II l;acl~grountl: 'l'hc 2004 Comprehensive Water Study identified the need for additional sources of xvater to ~ct-x~c thc projectcd growth of the City. The study indicated that construction of three (3) new water supply wells were required to meet immediate projected growth needs. The Minnesota t)cpartmcnt o£ Natural Resources (MDNR) approved the implementation of these three wells, w itl~ thc stipulation that the City of Ramsey investigate alternative water supply sources to meet (~,,,,~t)ing futurc water supply needs. The City of Ramsey draws water from the Franconia lro~mm Galcsvillc (FIG) aquifer. This aquifer also serves neighboring communities. The MI)NR is reviewing the overall water use in the region and has raised significant concerns ~'cg~t~'ding thc ability of the FIG aquifer to meet the water needs of the region. Implementation of the three new wells has begun, with Well 6 projected to be online by the end ~l' tl~c ycar. The City Council authorized retention of Bolton & Menk, Inc. for design services on Wells 7 & 8 at thc April 12, 2005 meeting. The request for authorization to construct these xvclls will be brought to the council in a separate case. Wells 7 & 8 will be online by the end of 2()(1(i. Thc next step in the implementation of of the water supply plans is to further investigate l)otc~ti~l alternative water sources. The 2004 Comprehensive water Plan recommended that the Mississippi River be investigated as an alternative water source. This investigation will include evaluation off the availability and treatability of the water appropriated from the Mississippi f~,ivct', as well as a detailed cost evaluation the water supply and treatment facilities. Stal'l' requested a proposal fi'om Bolton & Menk, Inc. for initiating the investigation of the use of thc Mississippi River as an alternative water source for the City of Ramsey. The first phase of ~l~c process includes Review of the Hydrogeological Data available, Test Borings and Aquifer 'l'esting, Detail Aquifer Testing, Membrane Filtration Pilot Plant Testing and preliminary Water .~t~pl3ty Treatment facility design. 'l'hc proposed water supply facilities will draw water indirectly from the river using a riverbank infillration system. Riverbank filtration draws water utilizing wells and or collector galleries l'ro~n the surficial aquifcrs fed by the river. Thus the raw water intake does not draw water dircclly fi'om thc surface of the river, but rather draws water which is "filtered" through the rivcrl>anl<. This type of system provides a level of protection from debris and suspended solids ti~at may be iri the river. The raxv water is then piped to the surface water treatment plant. Thc review of the hydrogeology will provide data on potential areas for locations of the test wells. The hydrogeology review will help narrow the focus so that the wells are located in the n~ost favorable locations. This will help determine locations where access agreements are m:cclcd prior to drilling the test wells.