R97-146 ACCEPTING THE PROPOSAL AND AUTHORIZING AN AGREEMENT

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The Cisco Well Field was constructed in the mid 1950's to provide a source of supplemental water. This well field consists of two wells located along the Sangamon River, approximately 13 miles upstream of the City's North Water Treatment Plant. The wells discharge into a small surface channel that drains directly to the Sangamon River. Well #1 has been inoperable since 1993. A seepage study was conducted in 1991 by the U.S. Geological Survey to deternune the estimated loss of water between the well field and Lake Decatur. The USGS study estimated the seepage loss to be 65 percent of the rated capacity of the well field. The Water Resources, Storage and Production Study of the City's water system, prepared in 1996 by HARZA Consulting Engineers and Scientists under contract to the City, recommended making additional studies of these two well fields. This recommendation noted the need for the City to determine the reliable production capacity from the well field and the impacts to the �, neighboring private wells. This information is important to enable the City to make critical decisions regarding the expected production and delivery of water from the well fields to meet the � City's water resource needs. Staff agreed with this recommendation and prepared a Request for �I Proposal (RFP) to obtain professional services to perform the required studies prior to the City � committing major capital investments for the delivery of water from the well fields. The RFP was sent to several firms and two government agencies capable of providing the expected services for the needed study. Four proposals were received. Proposals were received from, listed in alphabetical order: Ground Water Associates, Inc. Illinois State Water Survey Layne GeoSciences, Inc. United States Geological Survey After a review of the proposals, staff decided to interview three of the proposers before making its final recommendation. The three proposers interviewed were: Ground Water Associates, Illinois State Water Survey and Layne GeoSciences. The selection committee decided that Layne GeoSciences best met the needs of the City for this study. Staff has completed negotiations with Layne GeoSciences for the agreement. A copy of the agreement is attached. The services include an evaluation of the existing condition of the well fields to advise the City of needed repairs and upgrades to the well fields. This information will be used to further assess the costs of the water the City would receive from its well fields. The study will also identify the extent of the impacts on neighboring wells when the City operates its well fields. This will provide a basis for the City to develop its strategies and programs to mitigate these impacts. The agreement makes provisions for additional 5-day pumping tests or an extended 30-day pumping test should the City decide this additional testing is needed based on the information and data obtained in the study. The step drawdown test included in the scope of work is expected to provide sufficient and reasonable data and information for use in the computer model to make the determinations regarding the well fields. An additional option, is for City staff to be trained in the use of the computer software used by the consultant to model the well field and Mahomet Aquifer. Staff is of the opinion, at this time, that the expected limited use of the software by staff does not justify the training.