Effect of Amendment Type and Incorporation Depth on Runoff from Compacted Sandy Soils

Abstract

Increased runoff rates and volumes from urbanizing watersheds are generally attributed to increased imperviousness within the watershed. While pervious surfaces in urban areas are often credited with having little runoff contribution, soil compaction can reduce infiltration capacity, leading to increased runoff. The objective of the research reported in this paper was to evaluate the hydrologic response of potential treatments for mitigating urban soil compaction. In the lysimeter study of the research reported in this paper, two Florida soils [(1) Arredondo fine sand, and (2) Orangeburg fine sandy loam] were compacted and potential mitigating treatments were applied to evaluate runoff reduction. Treatments combined two incorporation depths [(1) 10 cm, and (2) 20 cm] with three amendment cases [(1) no amendment, (2) compost, and (3) fly ash] and were applied to both soils. A set of compacted lysimeters for each soil were designated as controls and remained compacted (no treatment) throughout the research reported in this paper for comparison with amendment type and depth treatments. Runoff volumes were collected from 19 natural and simulated events over a 5-month period. Natural rainfall events ranged in depth from 4–59 mm over 3–23 h (average intensity,