Goodwater creek experimental watershed: Modeling hydrology with the AgES model

Authors: Schumak, Catherine; Green, Timothy; KIPKA, HOLM - Colorado State University; IPPOLITO, JAMES - Colorado State University; ANDALES, ALLAN - Colorado State University; Lighthart, Nathan; RITTER, AMY - Waterborne Environmental

Submitted to: Annual American Geophysical Union Hydrology Days
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: n/a

Technical Abstract: Goodwater Creek Experimental Watershed (GCEW) is a small (72 km2), but mighty watershed located near Centralia, Missouri. GCEW is a headwaters watershed of the Salt River basin which flows to Mark Twain Lake, a major source of drinking water for the area. Thus, monitoring nutrients and pollutants is important to protect human and environmental health. The site was established in the early 1970’s as part of the Central Mississippi River Basin Long-Term Agroecosystems Research to study the effects of conservation practices and claypan hydrology on water quality at the watershed scale. Since then, GCEW has been studied extensively, with streamflow and climate data beginning in 1971 and water quality and socio-economic data in 1991. The watershed contains primarily agricultural land, with soybeans, corn, and wheat being the main crops. An average of 1000 mm of precipitation falls annually with the wettest seasons being winter and spring. The topography is flat with only 37 m difference between the watershed divide and the stream outlet. The claypan soils, defined by a subsurface argillic clay layer with 50-60% clay content, have very low hydraulic conductivity, making fields prone to high runoff. This makes the watershed vulnerable to surface transport of sediment, herbicides, and nutrients. Atrazine, a common herbicide, has concentrations consistently amongst the highest for a watershed in the US. This project models the hydrology of Goodwater Creek using the Agricultural Ecosystem Services (AgES) watershed model developed by the Agricultural Research Service. AgES is a fully distributed model that can represent the spatial distribution of climate and physical watershed characteristics to route water explicitly through Hydrologic Response Units (HRUs) and stream reaches. While GCEW has been modeled before, this will be the first time using AgES. It is vital to realistically model the hydrology of the watershed, as the hydrology is a major driver in the fate and transport of sediment, nutrients, and pesticides. The hydrology modeling sets the stage for future modeling efforts including nitrogen, phosphorus, and atrazine.