Impact of the depth of a soil compaction layer on stormwater runoff and flooding in urban watersheds

Shirley Clark, Zorana Mijic, Jonathan Fischer and Travis Peters


Urban development has resulted in the compaction of soil, which changed soil porosity and reduced the ability of water to infiltrate into the soil. Estimating the amount of runoff entering stormwater pipes and stormwater control measures (SCMs) requires models that can adequately capture the amount of rainfall that becomes runoff and the amount that infiltrates into the soil and does not enter the stormwater system. This research study combines field measures of compaction, long-term soil moisture sensing, and stormwater runoff modeling in a demonstration watershed to improve understanding of the impacts of a compaction layer (soil resistance > 2,000 kPa) on the amount of water that will infiltrate. The results show that the compaction layer will delay the movement of water into the lower layers of a soil profile and that delay may be a function of rainfall intensity and/or rainfall depth. The modeling highlights the impacts of limited soil infiltration. For a flooding storm (120 mm in 87 minutes), increasing the depth to the compaction layer from 3 cm to 8 cm reduces the amount of time the node is flooded by 50% and the maximum flood depth from 0.61 m to 0.15 m. This research highlights the vital importance of soil compaction layers in understanding the movement of stormwater in the urban environment.  

 Click here to download a static PDF version of the presentation.

 Click here to watch recorded presentation on YouTube.

Permanent link: