Residential Storm Water Standards
Safe Harbor designs storm water systems for ground water recharge, with zero discharge off site. Residential construction results in significant alterations to soil permeability during rain storms. Impervious surfaces such as roofs, driveways and sidewalks generate cumulative sheet flow and point source discharge during a heavy rainfall. Without ground water recharge, potentially significant up slope sheet flow contributes to down slope erosion and flooding. In a natural system, this water would be absorbed by native tree canopy, vegetation and soil. The water would percolate vertically through the soil and then move in a horizontal flow towards the nearest water body. Cape Cod’s water bodies are ground water fed. Native vegetation and soils act as a natural filter for pollutants, excess nutrients and chemicals. Safe Harbor uses Massachusetts Smart Growth techniques to create site specific, residential, ground water recharge systems for the protection of our water resources.
Safe Harbor advocates for minimal de-vegetation and grade alterations on construction sites to minimize potential storm water generation and discharge. This also significantly reduces erosion control and re-vegetation costs. Native stem-leaf-root systems naturally reduce runoff velocity and remove pollutants, sediments and silt. These systems also contribute to habitat values.
In a natural system, significant percentages of rain water evaporates or transpire through vegetation.
Storm water management is site specific. Here are a few of the options we consider.
5.  Vegetated Swale
6.  Stone Swale
design and evaluate storm water management options based on sustainability, low profile, low maintenance and gravity driven systems. Most of these systems are also low cost. Check out our new Storm Water Management page under Educational Initiatives on our Home Page. This section is being frequently updated this fall.
Unmanaged storm water generated by impervious paving contributes animal, vehicle and road waste directly into our coastal wetlands. Workable management systems are available for municipal and residential use. Storm water should be infiltrated into the ground water table to meet performance standards for wetland areas.
Winter snow disposal by municipal and residential plows create concentrations of road salt, vehicle and road waste in frozen storm water. Plowed snow should be stored in swales, away from harbors.
