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EFFECTS OF LAND USE AND TOPOGRAPHY ON SOME WATER QUALITY VARIABLES IN FORESTED EAST TEXAS 1
Author(s) -
Chang Mingteh,
McCullough Jack D.,
Granillo Alfredo B.
Publication year - 1983
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1983.tb05313.x
Subject(s) - hydrology (agriculture) , water quality , kjeldahl method , environmental science , watershed , nitrate , pasture , drainage , total suspended solids , drainage density , nitrogen , sediment , chemical oxygen demand , forestry , environmental engineering , chemistry , geography , ecology , geology , paleontology , geotechnical engineering , organic chemistry , machine learning , wastewater , computer science , biology
Spatial variation of five water quality variables were analyzed using composite water samples collected periodically from eight small watersheds (11.4–71.6 km 2 ) in forested East Texas during 1977 through 1980. Based on 31 observations during the four‐year period the average yield of nitrate‐nitrite nitrogen (NNN), total kjeldahl nitrogen (TKN), total phosphorus (PO4), chloride (CHL), and total suspended sediment (TSS) were 1.43, 21.96, 3.09, 50.11, and 90.39 ka/ha/yr, respectively. Compared to the water quality standards of the U.S. Environmental Protection Agency (1976) and the Texas Department of Water Resources (1976) for CHL, TSS, and NNN, none of the observations exceeded the limits for public water supplies. The study showed that forested watersheds normally yielded stream flow with better quality than that from agricultural watersheds. Watersheds of greater percent of pasture area, mean slope, stream segment frequency, and drainage density produced greater concentrations for these five chemical parameters in water samples. Meaningful equations were developed for estimating mean average yields for each chemical parameter for each watershed with R 2 ranging from 0.77 to 0.96 and standard error of estimates from 17 to 33 percent of the observed means.