HYDROLOGY
AND WATER QUALITY OF A NATURAL FORESTED WETLAND IN THE COASTAL PLAIN
Near
TRS site, Plymouth, NC
G. M. Chescheir, R.W. Skaggs, and J.W. Gilliam
The Atlantic Coastal Plain is rich in natural resources which are extremely valuable to the region and the nation. Prudent management to sustain and utilize the wealth of our natural resources requires a thorough understanding of the functions and relationships of the different land types and uses in the region. Unmanaged wetlands make up a large proportion of the land in the region and cannot be neglected in a complete analysis of regional hydrology and water quality. The desirable hydrology and water quality of wetlands are standards to which other land uses are compared, but research to characterize and quantify the complex functions and processes of these systems is still incomplete.
The purpose of this research is to quantify the hydrology and water quality on a natural unmanaged forested wetland with the ultimate goal of comparing the observed hydrologic and water quality parameters to those on managed forest and managed agricultural lands. We are concurrently conducting research on the hydrology and water quality on managed forest and managed agricultural lands.
This research project involves both field and modeling studies. A three year field study is being conducted to quantify all components of water and nutrient balances in the system. Existing process-based models for simulating the hydrology and water quality for agriculture and silviculture are being adapted for use on natural wetlands and validated using the data collected from the field study. The models and methods developed in this project will allow comparisons between unmanaged wetlands and managed land uses in the region. They will also facilitate complete evaluations of watersheds composed of multiple land uses.
The field study of a natural forested wetland has begun at the Tidewater Research Station near Plymouth, NC. A watershed within the wetland has been selected for intensive study. The watershed is approximately 135 ha with very shallow streams leading to well defined outlets. The watershed is very flat with ground elevations varying by less than 1 m. A hardwood forest covers most of the watershed with some pines located on the higher elevations along the boundaries. Eight kilometers of trails have been cut on the watershed to allow access for the study. Measurement stations have been located along the trails (Figure 1) and points of known elevations have been determined at each station by survey. Wells for determining the elevation of shallow groundwater and surface water have been installed at 27 stations. Water elevations are being measured at biweekly intervals at 19 station and continuously at eight stations. Water quality samples collected biweekly at six stations and continuously at two stations are being analyzed for total nitrogen, nitrate nitrogen, ammonia, total phosphorus, sediment and chloride. Weir and flume structures are being installed at the two watershed outlets to quantify the flow of surface water from the site. Soil moisture is being measured at six stations using time domain reflectometery.