Goodwater Creek Experimental Watershed LTAR- Representing Runoff-Prone Environments.

In response to broad calls for a Long-Term Agro-Ecosystem Research (LTAR) network, USDA-ARS, after review of competitive applications by an independent panel of experts, announced the initial 10 members of the ARS LTAR. These sites are expected to be joined by others in a national network after a broader call for applications.  One of the ten, the Goodwater Creek Experimental Watershed (GCEW) LTAR is operated by the USDA-ARS Cropping Systems and Water Quality Research Unit located in Columbia Missouri, on the campus of the University of Missouri. The core research infrastructure is the 72 km² GCEW, located approximately 50 km NNE of Columbia. This watershed represents surface-runoff-prone and documented erosive soils found in several Midwest and central states of the southern corn belt (IL, MO, IA, NE, and KS), and is dominated by surface runoff despite gently sloping topography because of a high-clay layer that restricts downward water flow. Most soils within the basin are classified as Hydrologic Group C or D by NRCS. Average annual precipitation is about 1000 mm per year, and stream flow (based on GCEW data) accounts for about 30% of precipitation. Runoff accounts for about 85% of total stream flow. GCEW was established in 1971 with weather data, a dense raingage network, and weirs at the 12, 28, and 72 km² scales. In 1991, water quality measurements were added at those and both plot and field scales for surface water and at a number of groundwater well nests. An automated weather station was added in 1993. In 2004, 12 additional larger-scale basins (200 to 1200 km²) were instrumented, eight of these co-located with USGS flow sites. Since 2010, 6 of the 12 have been retained to provide a combination nested and parallel design from 12 to 750 km². An overview of research from the GCEW LTAR will be presented, with example data and analyses being done and planned.