In 2004, Illinois began Cedar Lake restoration with 3 projects to curb erosion. 18 years later, Cedar Creek was delisted for 3 impairments after sediment and TSS improved

Cedar Lake erosion restoration Illinois: A 2004 study found extensive erosion along Cedar Lake, with about 200,000 feet of shoreline, roughly four, fifths of the lake's shore, classified as at least slightly eroded. Many areas had severe erosion.Stabilization efforts followed through Clean Water Act (CWA) Section 319(h) projects aimed at reducing sediment and nutrient loading to Cedar Lake and lowering the pollutant load reaching Cedar Creek. Projects in 2009, 2015 and 2021 focused on eroding shorelines and gullies.By 2022, Cedar Creek had been removed from the Illinois Section 303(d) list for sedimentation/siltation, dissolved oxygen (DO) and total suspended solids (TSS) impairments.Cedar Creek faced multiple water quality problemsCedar Creek was identified as not supporting its aquatic life designated use in Illinois' 2010 Section 303(d) list. The creek was impaired for sedimentation/siltation, DO and TSS, with the impairments caused in part by hydrologic modification.Cedar Lake was created in 1974 by impounding Cedar Creek, turning the headwaters into a reservoir that serves as a water supply for the City of Carbondale.You Might Also Like:The lake receives nearly all of its rainfall from tributaries in the Cedar Lake-Cedar Creek watershed, including a 3.78-mile reach of Cedar Creek headwaters that flows into the lake. The watershed includes forest surrounding the lake and its tributaries, farmland and residential areas, with a concentrated residential area in its northeastern corner.Restoration focused on eroding shorelines and gulliesThe 2009 project completed 10,786 feet of shoreline stabilization and 2,184 feet of gully stabilization, along with one Water and Sediment Control Basin.The 2015 project added 13,632 feet of shoreline stabilization and 7,100 feet of gully stabilization. It also included 124 stabilization structures and three Water and Sediment Control Basins to stabilize 2,100 feet of agricultural gullies.The 2021 project completed 12,419 feet of shoreline stabilization, plus another 360 feet to replace gully stabilization that could not be completed. A further 1,219 feet of gully stabilization was completed where access was possible.You Might Also Like:Some proposed gullies could not be reached because of the terrain in the forested areas surrounding Cedar Lake. Additional shoreline stabilization was therefore carried out in their place.Breakwaters with transitional wetlands were used where possible, while traditional riprap revetments were used when necessary. Rock grade stabilization structures were used for gullies.The projects reduced sediment and nutrient pollutionTotal estimated nonpoint-source reductions from the projects were 23,658 pounds of nitrogen, 11,828 pounds of phosphorus and 11,844 tons of sediment.The final report for the 2021 project also said the lake manager and local fishermen reported observable improvements in the lake's clarity and water quality.You Might Also Like:Monitoring showed Cedar Creek met delisting criteriaCedar Creek had to meet specific water quality conditions to be removed from the impaired waters list.DO had to reach at least 5 mg/L. Visual inspection also had to show no offensive sediment conditions, with no more than 50% of the stream bottom consisting of silt, mud or equivalent fine sediment.For TSS, the recommended maximum concentration was 116 mg/L.The 2018 Illinois Environmental Protection Agency sampling cycle showed TSS concentrations below the recommended maximum. DO also remained above the 5.0 mg/L minimum, compared with the 2013 cycle when the creek was still impaired for DO.Visual inspection determined that offensive conditions for sediment and TSS were no longer present.Cedar Creek was delisted in 2022The IL_NA-01 reach of Cedar Creek, covering 4.38 miles, was removed from the 2020/2022 Section 303(d) list for sedimentation/siltation, DO and TSS.The extensive work on Cedar Lake and other upstream sources of nonpoint-source pollution likely helped improve water quality in this section of Cedar Creek.The downstream picture was different. At Cedar Creek IL_NA-02, impairments for sedimentation and DO returned after the creek connected with several other waterbodies draining adjacent watersheds.