Sediment quality and quantity issues related to the restoration of backwater lakes along the Illinois River waterway

Abstract

Sedimentation has severely impacted backwater lakes along the Illinois River. The State of Illinois and the US Army Corps of Engineers are currently involved in a joint effort to address ecosystem degradation within the Illinois River Basin, and excessive sedimentation of backwater lakes and side channels is a primary cause of that degradation. Necessary parts of the overall restoration effort are to adequately characterize both the quality and quantity of backwater lake sediments prior to implementing any restoration efforts, and to identify potential beneficial reuses of dredged sediments. This paper summarizes some of our efforts in these areas with an emphasis on Peoria Lake which has received the most attention to date. Sediment characterization has included detailed bathymetric surveys, sediment dating with 137Cs, chemical and mineralogical characterization of sediments to three meters depth, analysis of recent sediments (to 30 cm depth) for acid-volatile sulfide and simultaneously extracted metals, and analysis of ammonia and toxic metals in sediment pore waters. Dredged sediments have also been used in various trial projects to demonstrate potential handling and beneficial reuse strategies. Some significant findings of these studies are: 1) Long-term sedimentation rates are high, and average 1–3 cm y−1; 2) total concentrations of several trace metals (e.g., Pb, Cd, Ni) and PAH compounds sometimes exceed consensus-based probable effect levels for sensitive sediment-dwelling organisms; 3) pore water dissolved ammonia concentrations in Peoria Lake are potentially toxic to sensitive sediment-dwelling species; and 4) weathered sediments can make productive agricultural soils.

Identifying the causes of sediment-associated contamination in the Illinois River (USA) using a whole-sediment toxicity identification evaluation

“…The IRC extends 525 km from the Des Plains River to the Mississippi River [13]. This major tributary of the Mississippi River drains 44% of the land area or approximately 75,000 km 2 of Illinois and portions of Wisconsin and Indiana [13].…”

“…This major tributary of the Mississippi River drains 44% of the land area or approximately 75,000 km 2 of Illinois and portions of Wisconsin and Indiana [13]. Twentyone surface sediments were collected from the IRC between river-miles 76 and 320 in the summer of 2007 (Fig.…”

Aquatic habitat changes within the channelized and impounded Arkansas River, Arkansas, USA

“…This pool is the most lentic of the 11 pools, and it has lost nearly 22% of its backwaters over the past two decades. Managers will need to understand how this loss of habitat will influence ecological processes (river productivity and population dynamics) and determine if remedial activities, such as dredging, are an option (Machesky et al, 2005). The use of remote sensing data and databases such as the GSW may provide resource managers a tool to assess habitat changes along rivers that inform biotic responses observed in ecological monitoring activities.…”

Phosphorus Speciation in Stream Bed Sediments from an Agricultural Watershed: Solid-Phase Associations and Sorption Behavior

“…Iron oxide P could also be released if sediments go anoxic but that is not likely over significant reaches of the watershed itself. Unlike most Midwest U.S. rivers there are no reservoirs along the main stem of the Spoon River where thicker accumulations of finegrained sediments would allow reducing conditions to develop, as for example in the downstream Illinois River (Machesky et al 2005).…”