Ponding studies at the Woodbury recharge basin on Long Island, N.Y., show that the principal zones controlling infiltration are a surface-loam stratum and an intermediate gravelly, sandy loam stratum. The saturated hydraulic conductivities of these strata are 0.90 and 0.1 ft per day, respectively. The surface loam acts as the principal zone controlling infiltration until a perched ground-water mound develops above the intermediate gravelly, sandy loam and extends to the bottom of the surface loam; then the intermediate gravelly, sandy loam becomes the principal infiltration controlling zone. Infiltration rates at 15.6° Celsius are 1.4 ft per day when the surface loam is acting as the principal controlling zone and 0.5 ft per day when the intermediate gravelly, sandy loam is acting as the principal controlling zone. Projections of the probable infiltration rates associated with both the partial and the complete removal of the surface-loam stratum show that if recharge continues for several days total infiltration would not be greatly different whether or not the loam stratum is completely removed. The principal advantage of completely removing the surface-loam stratum is the resulting greater infiltration capacity during the early stages of ponding. This advantage is offset by potential problems associated with more intensive clogging of the subsurface controlling zone.
