Clark, Shirley, Civil, Construction, and Environmental Engineering, Penn State Harrisburg, 777 W Harrisburg Pike, # W236F, Middletown, PA,17057, sec16@psu.edu; Mijic, Zorana E., Civil, Construction, and Environmental Engineering, The Pennsylvania State University, 777 W Harrisburg Pike, Middletown, PA 17057, zorana.mijic@psu.edu; Iskander, Benjamin E., Civil, Construction, and Environmental EngineeringThe Pennsylvania State University, 777 W Harrisburg Pike, Middletown, PA 17057, bhi5012@psu.edu; Aches, Michael E., Civil, Construction, and Environmental Engineering, The Pennsylvania State University, 777 W Harrisburg Pike, Middletown, PA 17057, maa6532@psu.edu; Fischer, Jonathan E., Civil, Construction, and Environmental Engineering, The Pennsylvania State University, 777 W Harrisburg Pike, Middletown, PA 17057, Bennett, Bryan E., Mechanical Engineering, The Pennsylvania State University, 777 W Harrisburg Pike, Middletown, PA 17057.
Urban development compacted soil, which reduced the ability of water to infiltrate. Land development practices historically compacted the soil over the entire property, rather than restricting compaction to areas where structural support was required for buildings and roads. Estimating the amount of runoff entering stormwater pipes requires models that can adequately capture the amount of rainfall that becomes runoff, after losses such as infiltration. 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 or 300 psi) on the amount of water that will infiltrate. The compaction layer delays the movement of water into the lower layers of a soil profile. The modeling highlights the impacts of limited soil infiltration. For a flooding storm (120 mm [4.71 in] 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. It also highlights the importance of not compacting areas where structural soil strengths are not required, as well as the importance of soil restoration in reducing urban flooding in these times of climate change.
soil compaction, urban runoff, land development