wAbstract
@We examined total Kjeldahl nitrogen (TKN) loading to a small
forested stream during storm events. We hypothesized that upper
soil and litter layers in riparian area are primary source of
higher TKN concentrations during storm. A storm water sampling
program was carried out to gather requisite flow and water quality
data to calibrate and validate water and nutrient components of
the Riparian Ecosystem Management Model for TKN. Water quality
and storm flow data collected from January 2000 to December 2003
were used to simulate the hydrology and nitrogen transport over
a second-order watershed within the Fort Benning Military Installation,
Georgia. Intensive sampling conducted from October 2002 to May
2003 provided the necessary data to characterize the rising limb,
peak, and recession limb of six major storm events. Simulated
runoff and storm TKN loads were compared with their corresponding
observed or calculated values. Hydrology and nitrogen data collected
from February 21, 2003 to December 31, 2003 were used for the
model validation. The hydrology component of the model showed
a Nash-Sutcliffe efficiency of 87 for the validation period.
The average absolute difference between simulated and calculated
TKN loads was 25. Even though the monthly water budget indicated
the dominance of subsurface flow, TKN contribution from direct
runoff was significantly greater than that from subsurface flow.
On an average, 73 of the observed total TKN load at the watershed
outlet was contributed by surface runoff during storm events.
The results suggested that the surface runoff during the storm
events washed off the nitrogen from the forest floor and transported
to the stream.
Keywords: Forested watershed; Fort Bennin; Low nutrient systems;
REMM; Riparian area; Total Kjeldahl nitrogenx
Introduction
Study area
Methodology
@Data and model setup
@Model calibration and validation
Results and discussion
@Model calibration and validation
@Hydrologic and nitrogen budgets
Conclusions
Acknowledgements
References