Current research projects
Groundwater and nutrient flux in an ephemeral stream
In modeling instream fate and transport of nutrients, it is important
to understand potential sinks and sources. Earlier work by researchers
at TIAER indicated a potential uptake of phosphorus within the
mainstem system at low to moderate flows that appears to be released
when higher flows occur. There is speculation based on the fact
that high phosphorus concentrations are often associated with
baseflow samples that headwater reaches may also play an important
role in groundwater/surface water interactions with phosphorus.
This study was conducted to determine if groundwater acts as a
source or sink of soluble phosphorus for a second order headwater
reach. This evaluation was conducted using shallow bank wells
and instream piezometers to evaluate groundwater elevation gradients
with respect to surface water levels. A mass balance approach
using tracer studies at low flows and storm monitoring at higher
flows was used to evaluate phosphorus losses or gains along the
reach. Phosphorus concentrations in sediments collected when the
bank wells were constructed were evaluated for horizontal gradients.
Additional streambank and streambed sediment samples were also
analyzed to help determine the potential for phosphorus movement
between sediment and the water column. Results from this study
will be used to inform the model refinement effort with regard
to characterizing instream fate and transport of phosphorus.
Evaluation of spring-fed wetlands in East Texas
Very little information exists about the geomorphic setting, hydrodynamics,
or water chemistry of the wetlands in this region of the country.
Such questions are important because the hydrologic, geologic,
geomorphologic, and biologic processes interact to create the
wetland ecosystems. The geologic setting, when combined with the
hydrology, is key to the character of the soils in which the wetland
plants are rooted. An understanding of the geologic and geomorphic
framework is critical to development of decision-support systems,
which will help manage complex wetland dynamics. The objectives
of this study are to define the hydrology of hillslope bogs in
the Gus Engeling area. Within that goal there are several specific
objectives including determination of the hydrogeomorphic setting,
the age and geologic history of these hillslope bogs.
Reconstructing Reservoir Trophic status using paleolimnological
and geochemical analyses of sediment cores
The primary objective of this Project is to reconstruct the trophic
status of reservoirs using paleolimnological and geochemical analyses
of sediment cores. Reconstruction of the trophic status of reservoirs'
will help infer historical trends in water quality of reservoirs
in the Central Texas region. Reservoirs in this region generally
support multi-purposes, including water storage, drinking water
use, general use for municipals and industries, and contact recreation.
To accomplish the primary objective of this Project, sediment
cores that penetrate the pre-impoundment surface will be collected
from several reservoirs and analyzed for selected biological and
chemical constituents. Data obtained from this Project will extend
our knowledge of reservoir biogeochemistry, especially that of
southern temperate reservoirs, as well as provide technical guidance
for TMDL development of reservoirs.
Past Research Projects