Premium
Pollutant Contributions from Irrigation Surface Return Flows
Author(s) -
Miller W. W.,
Guitjens J. C.,
Mahannah C. N.,
Joung H. M.
Publication year - 1978
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1978.00472425000700010007x
Subject(s) - irrigation , pollutant , environmental science , return flow , hydrology (agriculture) , pollution , surface water , surface irrigation , volume (thermodynamics) , regression analysis , environmental engineering , mathematics , chemistry , flow (mathematics) , statistics , ecology , biology , geology , geometry , physics , quantum mechanics , geotechnical engineering , organic chemistry
The purpose of this investigation was to examine the causes and sources of irrigation surface return flow pollution and the interrelationships among pollution constituents. Irrigation applications and surface return flows were metered, net applied water was computed, and the volume of infiltrated water was determined at four sites in the Carson Valley of Nevada during the 1974–75 irrigation seasons. Concentrations of TDS, BOD, NO 3 ‐N, TN, PO 4 ‐P, and TP were combined with flow volumes to compute the change in surface loading per irrigation and seasonally. Of those parameters studied, the major pollutants contributed by irrigation surface return flows were BOD and PO 4 ‐P, ranging from 13.6–52 kg/ha and 1.5–3.0 kg/ha, respectively. Minor contributions of TP (0.4 kg/ha) were recorded only at Site 3 during 1975. Multiple regression equations were determined in 1975 for concentrations of BOD as functions of the variables NO 3 ‐N, TN, PO 4 ‐P, and TP, and for DO d /DO s as a function of temperature and BOD. F ‐tests for all multiple regressions were significant. BOD = f (TN, TP) appeared the best predictor. Regression coefficients were significant at the 99% level ( t ‐test) and R 2 values ranged from 0.51 to 0.74. The coefficients of regression for DO d /DO s = f (temperature, BOD) were also significant at the 99% level; however, the R 2 was only 0.30. It may be necessary to include a rate factor to obtain greater predictability of such a relationship. Differences in water quality and load computations between the two years was attributed, in part, to changes in water quantities.