Fort Hood Long Term Sediment Monitoring

BREC WATER QUALITY and SEDIMENT MONITORING at Fort Hood

The commitment to long-term monitoring has provided data to assist Fort Hood land manager understanding of erosion trends and results of implemented management practices.  Since 1995 the Blackland Research and Extension Center’s (BREC) Water Science Laboratory has measured flow and sediment concentration in numerous Fort Hood streams.  In-stream water quality measurements are employed as surrogates for estimating training area condition related to maneuver activities and associated erosion.  This extensive dataset has been used to: support the Fort Hood Integrated Training Area Management (ITAM) program’s annual Range and Training Land Assessment, evaluate best management practice (BMP) effectiveness at reducing runoff and erosion (Wang et al. 2005), compare erosion trends between training areas with and without sediment retention ponds (Hoffman and Wolfe, 2002), and to compare benefits of contour ripping and compost applications to training areas (Wilcox et al., 2012).

IMPROVEMENTS in ENVIRONMENTAL MONITORING INSTRUMENTATION

Improvements in sensors, data recording technology, cellular-based telemetry, and Internet-based information distribution are currently driving Federal, State, and non-governmental organizations to develop and apply real-time monitoring strategies (USGS 2012).  These new systems provide nearly continuous water-quality/quantity information which can be used to directly or indirectly compute concentrations of many water-quality constituents.  For example, turbidity threshold sampling (TTS) can be used to accurately calculate suspended sediment loads by using measured turbidity (an optical parameter) as a surrogate for suspended sediment (Lewis 1996).

CURRENT MONITORING EFFORT

BREC currently manages six water quality monitoring stations equipped with rain gauges, stream level loggers and automated water samplers.  Gauges are strategically placed at sub-watersheds of interest, half of which represent Fort Hood’s western training areas (Figure 1).  A key location , the outflow of Cowhouse Creek immediately upstream from Lake Belton (Figure 1), permits the assessment of total sediment contribution by Fort Hood, relative to contributions of upstream sources (i.e., off the reservation).  BREC uses TTS instrumentation measuring and stream flow and sediment loads (as turbidity) in near real time (Figure 2).  Data is uploaded to BREC a server via cellular telemetry and made available to land managers via the internet.  The new TTS instrumentation represents a major improvement and modernization of Fort Hood’s water quality/sediment monitoring program.

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Figure 1. Fort Hood major streams, current monitoring locations (green) and proposed location for TTS station (red).

Figure 2. Screen capture from TTS software showing real-time collection of stream stage and turbidity. Note that sediment load (represented by turbidity does not follow hydrograph. Discrete sampling cannot capture actual loads that TTS can detect).

 

REFERENCES

Hann, CT, BJ Barfield, and JC Hayes (1994) Design hydrology and sedimentology for small catchments.  Academic Press, New York.  588pg.

Hoffman DW, JE Wolfe (2002) Evaluating Erosion-Reducing Best Management Practices with Water Quality Data on the Fort Hood Military Reservation. Eleventh Annual Integrated Training Area Management Workshop. August 19-23. Savannah, Georgia.

Lewis J (1996) Turbidity-controlled suspended sediment sampling for runoff-event load estimation.  Water Resources Research 32(7):2299-2310.

United States Geological Survey (USGS) (2012) National Real-Time Water Quality. http://nrtwq.usgs.gov/

Wang X, Hoffman DW, Wolfe JE, Williams JR, and Fox WE (2009)  Modeling the effectiveness of conservation practices at Shoal Creek Watershed, Texas using APEX.  Transactions of the American Society of Agricultural and Biological Engineers  52:1181-1192.

Wilcox BP, WE Fox, LJ Prcin, J McAlister, J Wolfe, DM Thomas, RW Knight, DW Hoffman, and FE Smeins (2012) Contour ripping is more beneficial than composted manure for restoring degraded rangelands in Central Texas.  Journal of Environmental Management 111:87-95.

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