Probabilistic description of runoff and leachate volumes from open windrow composting sites

Stormwater runoff generated from open windrow composting sites is often heavily polluted. Detention ponds are typically constructed to contain and treat runoff from these sites. For the proper sizing of detention ponds, runoff volumes from composting sites under rainfall events of different magnitudes need to be estimated. A conceptual rainfall-runoff model that captures the key hydrologic and hydraulic processes is developed in this paper for open window composting sites. Based on this model, closed-form mathematical equations are derived for the purpose of estimating the average volume of runoff per rainfall event, runoff with different return periods, and average leachate runoff from open windrow composting sites with impermeable pads. Example calculations not only demonstrate the capabilities of these equations but also illustrate the effects of regional climatic differences on runoff and leachate volumes.