Riesel
Watersheds,
Location – The Riesel experimental watershed, which
contains 340 ha of federally owned and operated land, was established in 1937. The still-active site was established in the
2372 ha Brushy Creek watershed near
Establishment – In the mid
1930’s, the United States Department of Agriculture Soil Conservation Service
(USDA-
Research
History - The Riesel watersheds represent one of the
longest active hydrologic research sites in the
Recent
publications demonstrating these contributions and describing these data are
listed below.
Harmel,
R.D., J.V. Bonta, and C.W. Richardson. 2007. The
Original USDA-ARS Experimental Watersheds in
Harmel,
R.D., K.W. King, C.W Richardson, and P.M. Allen. 2006. Runoff and Soil Loss
Relationships for the
Allen,
P.M., R.D. Harmel, J.G. Arnold, B. Plant, J. Yelderman,
and K.W. King. 2005. Field Data and Flow
System Response in Clay (Vertisol) Shale Terrain,
North
Harmel,
R.D., K.W. King, C.W. Richardson, and J.R. Williams. 2003. Long-Term
Precipitation Analyses for the
Monitoring
Infrastructure - The original infrastructure at
Riesel included multiple watersheds and rain gauges on private land in the
Brushy Creek watershed and on smaller sites on land purchased by USDA (fig. 2). Precipitation, runoff, soil erosion, and air
temperature data have been collected continuously on selected sites since the
late 1930’s. Compared to new sites, such
established sites have many benefits including the availability of historic
data and efficient adaptation to address emerging issues.
Runoff data
collection began in 1938 and continued in various periods from 40 watersheds
(0.1-2372 ha). Currently, 17 runoff stations are in operation on remnant
prairie, improved pasture, and cultivated cropland. Ten runoff stations are located at the outlet
of small, single landuse watersheds (1.2-8.4 ha) to
measure “edge of field” processes (fig. 1).
Four stations are located at the outlet of 0.1 ha plots. Three stations are located at the outlet of
larger downstream watersheds (17.1-125.1 ha) with mixed landuses
to evaluate integrated processes. Each
of these runoff structures is instrumented with a shaft encoder as the primary
water level (stage) recording device and with a float gauge-chart recorder and
a bubbler level recorder as backup devices.
Electronic automated samplers were installed in 2001 to collect runoff
samples, which are analyzed for nutrient and sediment concentrations. These automated samplers begin collection
when activated by a bubbler flow level recorder.
A lateral flow
station was installed in 1970 to measure lateral subsurface flow from a portion
of one watershed. To measure flow,
French drains installed perpendicular to the slope collect flow and release it
into a boxed, sharp-crested v-notch weir.
Since 2000, shallow groundwater levels in seven wells have been
monitored twice weekly with a hand-held “e-line” gauge.
Currently, 15
rain gauges are in operation within 340 ha, which makes Riesel one of the
denser rain gauge networks in the world.
Electronic tipping bucket gauges were installed with a datalogger in the late 1990’s to record rain data on 10 min
intervals. A standard rain gauge at each
site is used as a backup and calibration device (fig. 3). Since 1990, air temperature, solar radiation,
wind speed and direction, precipitation, and soil temperature have been
measured by an onsite weather station.
Installation of a
VHF radiotelemetry network was completed in 2001 to
improve data quality and collection efficiency.
From the onsite base station, equipment maintenance and calibration are
performed and realtime conditions are monitored. An automated data collection schedule runs
continuously and collects data daily from each field station. The base station is linked via phone modem to
a dedicated computer at the laboratory headquarters in