R2011-182 AUTHORIZING EXECUTION OF TASK ORDER NO. 16

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ATTACHMENT A FOR TASK ORDER NO. 16 FOR CONTINUING AGREEMENT FOR ENGINEERING SERVICES Owner: City of Decatur, Illinois Engineer: Black &Veatch Corporation Project: Potential Well Site Exploration Date: November 28, 2011 DESCRIPTION OF SCOPE OF SERVICES BACKGROUND Owner investigated possible local ground water resources near the South Water Treatment Plant (SWTP) in 2010 to supplement their existing Lake Decatur surface water supply. The Owner's goal is to identify resources that could produce 4,700 to 4,800 acre- feet per year of supplemental water supply, equivalent to 4.2 to 4.3 million gallons per day (MGD). A study authorized by Owner and conducted by Engineer in April 2010 revealed a 38 to 40 foot thick layer of saturated sand and gravel at a depth between 40 and 80 feet in an exploratory boring located about 100 feet from the north shore of Lake Decatur and about 3,000 feet southeast from the SWTP. Findings from the study are documented in Engineer's report titled "Evaluation of Shallow Groundwater Resources" dated July 9, 2010. Preliminary indications are that the formation appears to be similar to other aquifers in the area that have been estimated to be capable of producing single collector well yields of 2.1 to 3.6 MGD. The purpose of this hydrogeologic investigation is to (1) determine the aquifer hydraulic characteristics at several locations along Lake Decatur near the SWTP, and if necessary, downstream from the dam, (2) estimate potential collector well yields at one or two of the most favorable sites, and (3) develop preliminary collector well design criteria. The investigation will consist of the following major tasks: • Phase I Investigation (Basic Services) — Complete at least six (6) but no more than eight (8) test borings to determine stratigraphy, grain size distribution, static groundwater levels, and thickness of the aquifer. The test borings will be 2 City of Decatur Task Order No. 16 Rev. 11-4-11