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Percolation rates with surface layers of gravel or clay flocs on soil fed clear and turbid waters
Author(s) -
Lehman O. R.
Publication year - 1978
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr014i003p00539
Subject(s) - groundwater recharge , settling , surface runoff , flocculation , soil science , aquifer , geology , hydrology (agriculture) , soil water , environmental science , geotechnical engineering , environmental engineering , groundwater , ecology , biology
Suspended solids in water can plug the surfaces of aquifer recharge basins, and they are often chemically flocculated and removed in costly separate floc‐settling basins. This work evaluated floc and gravel filters on recharge surfaces as substitutes for settling basins. Disturbed soil in permeameters was treated with layers of small gravel and constant feedwater heads of either clear tapwater, untreated turbid runoff water, or turbid runoff water treated to form and retain flocs. Untreated turbid water reduced percolation rates more than the other feedwaters, and gravel layers markedly reduced percolation of all feedwaters. The percolation rate of water with flocs was only slightly less than that of tapwater. These results suggested that untreated turbid water or gravel layers are unacceptable for recharge surfaces. However, combinations of soil, gravel, and clay may have considerable potential for reducing percolation in water retention basins. Flocculation and settling seldom remove all fine particles from turbid water; thus a filter layer of flocs may extend the effective life of a recharge surface and eliminate costly separate floc‐settling basins.