Quantification of Postsettlement Deposition in a Northwestern Illinois Sediment Basin

Abstract

The purpose of this study was to quantify the postsettlement deposition in a 24 900‐m2 (2.49‐ha) sediment basin with a single outlet in a 105 400‐m2 (10.54‐ha) watershed and estimate the sediment delivery to a first‐order stream in northwestern Illinois. Methods included direct measurements of the eroded sediment deposited in the sediment basin. Buried A horizons (dated using fly ash as a time marker) identify the presettlement (≈1854) surface, which was overlain by as much as 116 cm of sediment. Volume of the sediment within the basin was calculated at 11 394 m3 with a weight of 16 480 Mg. The modern soils of the sediment basin were characterized, classified, and the spatial variability of the sedimentation process was examined. Based on representative measurements of postsettlement sediment delivery obtained from research of drainage basins having similar size or soil characteristics, it was inferred that 20 975 Mg of sediment was delivered to the stream with a total of 37 455 Mg of soil being removed from the watershed hillslopes as a result of accelerated soil erosion. The measured rate of postsettlement sediment accumulation has been approximately 0.34 cm yr−1. Based on the tightly packed deposits, redeposition probably occurred as overland flow during storm events, rather than as overland flow occurring after a rainfall or as rain‐splash transport. However, machinery traffic and cultivation could have contributed to the high soil bulk density. Intensive cultivation, biotic activity, and freeze‐thaw are probably responsible for destroying any evidence of stratification.

Impacts of Land-Cover Change on Suspended Sediment Transport in Two Agricultural Watersheds1

“…, 2009). In particular, historical postsettlement alluvium would be easily remobilized by streambank erosion because these materials lack internal structure provided by buried soil horizons developed during the Holocene (Bettis and Littke, 1987; Kreznor et al. , 1990; Beach, 1994).…”

“…Channel incision has occurred primarily through fine-grained postsettlement materials and Holocene alluvium, which lack the cohesive strength of the underlying pre-Illinoian till (Schilling et al, 2009). In particular, historical postsettlement alluvium would be easily remobilized by streambank erosion because these materials lack internal structure provided by buried soil horizons developed during the Holocene (Bettis and Littke, 1987;Kreznor et al, 1990;Beach, 1994). Several stages of channel evolution (Simon, 1989) were identified along the length of each stream, with areas of Stage III (degradation), Stage IV (degradation and widening), and Stage V (aggradation and widening) generally in the middle to lower stream reaches.…”

The role of impoundments in the sediment budget of the conterminous United States

“…Quantifying sedimentation that is widespread and patchy rather than concentrated and uniform is always difficult, usually relying on extrapolation from relatively few observations to a large area (the current study is an example). Estimates of alluvial or colluvial deposition have been made using a variety of methods including soil stratigraphic data (Trimble, 1974;Costa, 1975;Phillips, 1993;Beach, 1994), extrapolation based on sediment delivery ratios (Kreznor et al, 1990), and by difference from other terms (Trimble, 1981;Kondolf and Matthews, 1991;Phillips, 1991). In some cases, reservoir sedimentation is used as a tool to estimate sediment yield or sediment delivery to streams; in such cases, it is implicitly assigned to those components of the budget.…”

Using Fly Ash as a Marker to Quantify Culturally‐Accelerated Sediment Accumulation in Playa Wetlands

“…Kreznor et al . () used fly ash to quantify the sediment accumulation conditions at a basin level in Illinois. Hussain et al .…”

“…Jones and Olson (1990) characterized fly ash content to separate geological sediments and accelerated erosion sediments. Kreznor et al (1990) used fly ash to quantify the sediment accumulation conditions at a basin level in Illinois. Hussain et al (1998) use fly ash to examine erosion patterns on cultivated and uncultivated hillslopes.…”