Overview of
the Fort Hood Water Quality Project
Military training
activities at Fort Hood cause severe land disturbance, loss of vegetative cover
and sub sequent soil erosion. This multidisciplinary project is a
cooperative effort between Texas Agricultural Experiment Station (TAES), Natural
Resources Conservation Service (NRCS) and Fort Hoods Integrated Training Area
Management group (ITAM), working together to minimize sediment and nutrient
contamination of Lake Belton and the Leon River watershed.
This effort includes the implementation of Best Management Practices
(BMPs) installed by ITAM and NRCS, water quality monitoring by the TAES Water
Science Laboratory, and watershed modeling/evaluation by TAES.
Best Management
Practices:
BMPs designed to reduce
sediment losses resulting from the impacts of training exercises, have been
implemented by the Department of Public Works - Environmental Division, ITAM and
NRCS. BMPs include sediment traps, dedicated roadways, designated stream
crossings, brush clearing operations, riparian area establishment and rangeland
re-vegetation. The TAES Blackland Research Center Water Sciences
Laboratory manages thirteen instrumented stormwater monitoring sites; provides
laboratory facilities and personnel; and provides modeling evaluation through
use of the Soil and Water Assessment Tool (SWAT).
The establishment of
grass buffer zones (some times called Filter Strips or Riparian Areas) to reduce
sedimentation of flood control structures is a major part of the approach.
Buffer Zones are a widely used and proven tool that are effective in reducing
sediment losses. Buffer Zones are smaller in size and therefore more economical
to install, maintain and protect then the larger grassland areas found on Texas
rangelands. For this project, buffer zones are being established with grass
species that have been proven effective in Texas previous studies.
To further evaluate BMP effectiveness, stormwater runoff simulations are
being utilized to determine their effectiveness in reducing sedimentation under
the conditions found on Fort Hood.
Water Samples
The Water Science
Laboratory in Temple monitors sediment and other water quality parameters at
fourteen locations on Fort Hood to determine the effectiveness of the land
management practices. Thirteen monitoring sites are instrumented with rain
gauges, stream level loggers and programmable water sampling equipment. The
samples collected during storm water events are used to evaluate the
effectiveness of the BMPs implemented to reduce sediment loading. Additionally,
grab samples are collected monthly to establish a base line water quality index
for the area. Analysis of the samples are conducted in the Water Science
Laboratory where EPA approved laboratory procedures are utilized.
SWAT Model:
The
Soil-Water Analysis Tool (SWAT) model was developed to help water resource
managers in assessing water supplies, soil erosion, and water and sediment
transfers through complex watersheds. As a derivative of the Simulator for Water
Resources of Rural Basins (SWRRB), it operates on a subwatershed or grid cell
basis and allows for detailed or general scale simulations. SWAT uses a command
structure for routing runoff, sediment and chemicals through watersheds. Some of
the commands allow for routing flows, adding flows and updating measured data or
point source data. Key hydrologic components simulated include surface runoff,
sediment loading and deposition, channel transmission losses and channel flow
routing. The integration of these components is critical in estimating erosion
from exposed areas. Quantifying the characteristics of the watershed and using
the water quality sampling data will calibrate the SWAT model for the Fort Hood
watersheds. The SWAT model evaluates BMPs, under long time series that includes
extremes in precipitation.
Objectives:
Measures
of Success
Monitor
the water quality effectiveness of the BMPs installed by ITAM and NRCS on the
selected sites in the watershed project. In order for the Fort Hood and TAES
staff to evaluate the BMP technology, we must insure that the BMPs are water
quality protective.
To
monitor the effectiveness of the vegetative and managerial BMPs, paired
sub-watersheds need to be established to provide statistically valid
comparisons.
February 3, 2000
Dennis Hoffman, Project Leader
Steve Dagitz, Webmaster