Water Management on Construction Sites: Preventing Erosion and Runoff
Regulatory Requirements
Construction sites disturbing one or more acres of land are required to obtain NPDES stormwater permit coverage and implement a Stormwater Pollution Prevention Plan (SWPPP). Violations carry fines that can exceed $50,000 per day and result in project shutdowns. Beyond regulatory compliance, effective water management prevents soil erosion that undermines foundations, washes out excavations, and damages neighboring properties.
Erosion Control Best Management Practices
Install perimeter silt fencing and stabilized construction entrances before any earthwork begins. Phase grading operations to minimize the area of exposed soil at any given time. Apply temporary seed or erosion control blankets to disturbed areas that will remain inactive for more than 14 days. On slopes, install terracing or check dams to slow water velocity and reduce erosive force. Inspect all erosion controls within 24 hours of any rainfall event exceeding half an inch.
Dewatering and Groundwater Control
Excavations below the water table require dewatering systems that must be properly designed and permitted. Pumped groundwater cannot be discharged directly into storm drains without treatment or approval. Wellpoint systems work for shallow excavations in sandy soils, while deep wells are necessary for deeper cuts or clay soils. Budget for dewatering from the estimating phase—it is frequently underestimated and can represent a significant cost on projects with high water tables.