In the 1970s, folksinger Joni Mitchell sang with playful irony about real estate developers paving paradise and putting up parking lots. Although her lyrics warned about loss of natural habitat, they actually understated the environmental damage that can result from spreading watertight asphalt over permeable earth.
Rain and snowmelt on undeveloped land naturally seep into groundwater or flow into wetlands, with little damage to the environment. Covering land with pavement changes this. Uncontrolled stormwater runoff races into manmade drainage structures, carrying along rubbish, road salt, oil, dirt and other pollutants. Accelerated flows of stormwater cause erosion and local flooding. Sediments accumulate in adjacent wetlands, degrading their ecology. Water diverted into drainage systems does not infiltrate into the soil, so groundwater levels drop.
Fortunately, in recent decades we have learned to manage these problems. State and federal laws require developers and municipalities to adopt engineering solutions that minimize stormwater damage. At the federal level, the Environmental Protection Agency operates the National Pollution Discharge Elimination System permitting scheme (NPDES), which focuses on eliminating water pollution from industrial properties and municipal storm sewer systems. Facilities that pollute surface waters must obtain a permit through EPA, which can delegate its authority to states that properly administer the NPDES permit program. Forty-six states are currently authorized to administer the NPDES permit program. Massachusetts is one of four states without delegated authority (the others being New Hampshire, New Mexico and Idaho), so EPA administers NPDES in the commonwealth. Nevertheless, Massachusetts is no slacker in protecting wetlands from stormwater runoff, as developers here can attest.
Meeting Massachusetts’ Standards
The Massachusetts Department of Environmental Protection (DEP) has promulgated its own stormwater management standards under the Massachusetts Clean Waters Act and Wetlands Protection Act. DEP summarizes stormwater management standards in its Massachusetts Stormwater Handwork, which is considerably more readable than DEP’s published regulations. While DEP standards do not apply to single-family homes or to subdivisions with four or fewer homes that do not impact critical wetlands resources, other development projects must comply with DEP standards to varying degrees.
DEP standards prohibit new stormwater conveyance systems from discharging untreated stormwater directly into wetlands. Post-development stormwater discharge rates generally may not exceed pre-development rates. Developers must install infiltration systems to allow groundwater recharge. Stormwater management systems must remove at least 80 percent of post-construction suspended solids. Properties with higher pollution loads require enhanced measures. Developers must adopt plans to minimize erosion and sedimentation during construction, and to maintain stormwater management systems after construction. Finally, illicit discharges, such as wastewater and water containing industrial solvents, are forbidden.
Both EPA and DEP list best management practices (BMPs) for stormwater runoff. DEP’s list includes deep sump catch basins that separate oil and grease from stormwater, vegetated filter strips that slow runoff and promote infiltration, constructed stormwater wetlands that naturally remove pollutants, dry detention basins that control flooding and water quality swales that limit erosion. A fine example of a new development using various BMP’s is the MarketStreet project in Lynnfield, a joint venture of National Development and WS Development. MarketStreet Lynnfield shoppers enjoy trendy stores and restaurants, but land use professionals and conservationists can admire the shopping center’s grassy swales, stormwater detention basins, manmade wetlands and vegetated filtering strips, all of which abate stormwater impacts on the nearby Saugus River.
By using best management practices for stormwater runoff, new real estate projects accommodate the environment better than projects built when Joni Mitchell originally released “Big Yellow Taxi,” and probably better than when the Counting Crows more recently covered that enduring hit.
