| | 1: | | Title: | | | | | Volume/Number: | 2003 | | | | Issuing Agency: | | | | | Description: | The Illinois State Water Survey (ISWS) conducted sedimentation surveys of Lake Paradise and Lake Mattoon during 2001 in support of an Illinois Clean Lakes Program diagnostic/feasibility study to provide information on the storage and sedimentation conditions of the lakes. Both lakes are owned and operated by the City of Mattoon, which withdraws water from Lake Paradise as the raw water source for distribution of finished water and generally uses withdrawals from Lake Mattoon to maintain a more stable water level in Lake Paradise. The village of Neoga also withdraws water from Lake Mattoon for treatment and distribution. Since June 2001, Reliant Energy has operated a peaker power plant that has withdrawn water from Lake Mattoon for cooling systems. Lake Paradise and Lake Mattoon are located on the main stem of the Little Wabash River, a tributary to the Wabash River. The watershed is a portion of Hydrologic Unit 05120114. The dam for Lake Paradise is about 4 miles southwest of the City of Mattoon at 39 24' 47" north latitude and 88 26' 23" west longitude in Section 8, Township 11N., Range 7E., Coles County. The dam for Lake Mattoon is about 12 miles southwest of the City of Mattoon at 39 20' 00" north latitude and 88 28' 56" west longitude in Section 1, Township 10N., Range 6E., Shelby County.Lake Paradise was surveyed in 1979 and Lake Mattoon in 1980 as part of a previous cooperative study by the ISWS, the Illinois Department of Transportation - Division of Water Resources (DoWR), the Illinois Water Resources Center, and several departments at the University of Illinois at Urbana-Champaign. Lake Paradise lost 835 acre-feet (ac-ft) of its capacity as a result of sedimentation between 1908 and 2001. Approximately 481 ac-ft of this loss has occurred since 1931, which gives an annual sedimentation rate of 9.9 ac-ft since 1931. If this rate of sedimentation continues, the volume of Paradise Lake will be approximately half of the potential 1908 volume in the year 2013 and will be filled completely by sediment in the year 2118. Lake Mattoon lost 1,705 ac-ft of its 1958 capacity as a result of sedimentation between 1958 and 2001, a sedimentation rate of 39.7 ac-ft per year since 1958.If this rate of sedimentation continues, the volume of Lake Mattoon will be approximately half of the 1958 capacity by 2124 and will be completely filled in the year 2291. The sedimentation rates for Lake Paradise and its watershed for the periods 1931-1979, 1979-2001, and 1931-2001 were stable and ranged from 9.5 to 10 ac-ft.The long-term average annual sediment yield from 1931-2001 was 9.85 ac-ft. These sedimentation rates correspond to a rate of loss of lake capacity of 0.51 percent per year (1931-2001). The sedimentation rates for Lake Mattoon and its watershed for the periods 1958-1980, 1980-2001, and 1958-2001 indicate a reduction in net sediment yield from 66.9 ac-ft per year for 1958-1980 to 10.7 ac-ft per year (1980-2001).The long-term average annual sediment yield was 39.5 ac-ft (1958-2001). These sedimentation rates correspond to rates of loss of lake capacity of 0.51 percent per year (1958-1980) and 0.08 percent per year (1980-2001).The long-term average sedimentation rate for the lake is 0.30 percent per year (1958-2001). | | | | Date Created: | 9 24 2004 | | | | Agency ID: | CR-2003-04 | | | | ISL ID: | 000000000881 Original UID: 999999994353 FIRST WORD: Sedimentation | |
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