HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hubbard, R. K. Articles by Sheridan, J. M. Search for Related Content PubMed Articles by Hubbard, R. K. Articles by Sheridan, J. M. Agricola Articles by Hubbard, R. K. Articles by Sheridan, J. M.

Water and Nitrate-Nitrogen Losses From a Small, Upland, Coastal Plain Watershed¹

ABSTRACT

Surface runoff (SRO) and shallow-subsurface flow (SSF) from a small, upland, Coastal Plain watershed underlain by plinthite were monitored for a 10-y period. Samples collected during surface runoff and subsurface-flow events were analyzed for NO₃-N. The major water runoff loss from the system was found to be subsurface flow, accounting for 79% of total runoff loss, which occurred primarily from December through May. Nitrate-N concentrations in surface runoff and subsurface flow were relatively uniform over the period, averaging 0.47 and 8.75 mg/L, respectively. The combination of high volume of subsurface flow and its relatively high NO₃-N content, resulted in 99% of total NO₃-N loss via subsurface flow. Predictive equations for monthly surface and subsurface water runoff losses from this watershed were developed using multiple linear regression. The equations contain seasonal and climatic parameters, including pan evaporation. Tests of the equations with observed results gave significant (P 0.01) correlation coefficients, r, of 0.82 and 0.85 for surface runoff and subsurface flow, respectively. Mean surface and subsurface NO₃-N concentrations were multiplied by predicted monthly flows to compute predicted monthly NO₃-N losses. Comparison of predicted and actual monthly NO₃-N losses gave significant (P 0.01) correlation coefficients, r, of 0.59 and 0.86 for surface and subsurface flows, respectively. The good fit of predicted and observed results can be partially attributed to the seasonal and climatic data base collected over a relatively long period of 10 y.

Key Words: surface runoff • subsurface flow • water and nitrate loss predictions • water quality • plinthite

¹ Contribution from USDA-ARS, Southeast Watershed Research Laboratory, P.O. Box 946, Tifton, GA 31793, in cooperation with the University of Georgia Coastal Plain Exp. Stn.

² Soil Scientist and Research Hydraulic Engineer, USDA-ARS, Southeast Watershed Research Laboratory, P.O. Box 946, Tifton, GA 31793.

Received for publication July 24, 1982.