Infiltration flux for parallel strip water sources

The lateral component of flow and the infiltration from parallel strip sources of water on the soil surface were evaluated. Infiltration from such sources is two dimensional, having both a vertical and a lateral component. Warrick and Lazarovitch developed a method to calculate a two-dimensional steady-state infiltration rate from a single strip water source by adding an “edge effect” to the one-dimensional calculations. Because their analysis was for a single strip source, they did not account for the impact of parallel strip sources on this edge effect. In our research, a finite element model was used to obtain numerical solutions of the two-dimensional Richards equation and simulate the reduction of lateral infiltration of a strip water source due to the influence of adjacent strips. The interaction between neighboring parallel strips effectively reduces the steady-state infiltration rates through each strip. In this study, the effect of the spacing of strip water sources and soil texture on the infiltration from parallel strip sources of water on the soil surface was examined. In general, for a given strip spacing, the relative edge effect was reduced for increasing strip width, increasing flow depth, and finer textured soils. For transient flow conditions, the relative difference between two-dimensional and one-dimensional cumulative infiltration depth increases with time until, at steady state, it reaches a maximum constant value. For the conditions studied, the overall transient effect on the cumulative infiltration was found to be small (<5%). The results of this study were applied to different practical applications of stormwater infiltration under steady-state conditions using a factor to account for two-dimensional flow with strip source interactions.