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l <br /> � The survey will be conducted using an electonic fathometer or physical measurement <br /> with a sounding pole and differentially corrected Geodetic Positioning System (GPS). Collection , <br /> of the electronic hydrographic survey data will be coordinated by a laptop-based survey <br /> management program. Electronic survey data will be supplemented by sounding pole <br /> measurements of water and sediment depths at a minimum of 5 points on each lake transect. <br /> Samples of the accumulated sediments will be collected and analyzed for particle size <br /> distribution and unit weight. Eighteen particle size distribution and twenty-four unit weight <br /> samples will be collected. The results of the laboratory analysis of these samples will be used to <br /> discuss distribution patterns of sediment in the lake and calculate the mass of accumulated � <br /> sediments. Because these sediments typically accumulate in a very loose, unconsolidated mass <br /> that is subject to more consolidation over time it is important to determine the existing mass of ', <br /> the accumulated sediments to allow a more precise evaluation of consolidated sediment volume ', <br /> if lake dredging is a potential management option. �i <br /> Total cost for the sedimentation survey will be $39,751 and is detailed on the attached 'i <br /> budget sheet. -�- !, <br /> Project Plan and Deliverables III <br /> All field data collection, office or laboratory analyses, and report preparation will be the � <br /> responsibility of the Water Survey. The City of Decatur will fund the study and has no other <br /> specific commitment. <br /> The field work for the sedimentation survey will be scheduled at the earliest possible <br /> time. Laboratory and office analyses and calculations will require 4 to 6 months. Field work will <br /> be completed in Summer 2001, preliminary survey results will be available by December 31, <br /> 2001. A review draft of the final report will be completed by March 31, 2002 with a response <br /> date of Apri130, 2002. The final edited draft of this report will be completed by May 31, 2002. <br /> Reference <br /> Fitzpatrick, W.P., W.C. Bogner, and N.G. Bhowmik. 1987. Sedimentation and Hyc�rologic <br /> Processes in Lake Decatur and Its Watershed. Illinois State Water Survey Report of <br /> Investigation 107. <br /> 2 <br />