Infiltration pond design for highway runoff treatment in semiarid climates

Highway runoff disposal without concern for its specific characteristics ma y be associated with high material and environmental costs. An understandin g of storm water management has enlightened the importance of the impacts t hat nonpoint pollution may cause to both surface waters and groundwater. Se veral systems for highway runoff treatment exist, often based on detention and infiltration processes. This paper suggests a method for design and eva luation of the design of infiltration ponds for use in semiarid climates. T he design principle is based on capture and infiltration of the most pollut ed runoff. It takes into account the rainfall and soil hydraulic characteri stics for the determination of the design volume. Seasonal variations in ra infall and evaporation were considered. The soil characteristics-hydraulic conductivity, texture, pH, and cation exchange capacity-the volume of runof f which is infiltrated, and the infiltration area are used to calculate the movement of the most mobile heavy metal, Zn, in the soil. The method prese nted was based and applied to highway runoff but can be used for treatment of stormwater runoff from other sources.