A numerical solution to the Richards equation for three-dimensional (3-D), combined unsaturated and saturated flow was used to analyze pond seepage for geometries characteristic of the North Carolina Barrier Islands. Two- and three-dimensional seepage rates were obtained for 10 10 1m deep ponds, located 16-195m from the sinks, and spaced 10-190m apart for two profile depths: 3 and 9m. The numerical solutions were used to develop and test an approximate analytic solution for 3-D steady pond seepage. The approximate solution was obtained by dividing the flow regime into radial and linear flow domains. The predicted rates of the analytic solution agreed with those obtained from the numerical solution. 1990.
