Water Wise Communities

7. STORMWATER MANAGEMENT PROGRAM AND BYLAWS

Overview

In urban and suburban areas that are extensively paved with impervious surfaces, stormwater accumulates on land during rainstorms rather than infiltrating naturally into the ground. To prevent flooding, most cities and towns have built systems of underground pipes and basins to drain this stormwater directly to lakes and streams. However, this method of piping stormwater away can lead to several key problems:

Erosion of stream banks and downstream flooding due to higher storm flows and velocities in streams,
Water pollution due to contamination from roads, lawns, and paved areas,
Reduced infiltration of stormwater to recharge shallow aquifers, causing reduced “base” flows in streams and making less groundwater available for drinking water supply.

Stormwater discharges are currently regulated under a patchwork of federal, state, and local laws, enforced by various state and local authorities. Cities and towns with municipal separate storm sewer systems (MS4s) in “urbanized areas” in the Ipswich River watershed are required to comply with US Environmental Protection Agency Phase II regulations for small MS4s under the Clean Water Act National Pollution Discharge Elimination System (NPDES). By 2008, they will need to establish a stormwater management program that includes six elements:

Public education and outreach
Public participation and involvement
Illicit discharge detection and elimination
Construction site runoff control
Post-construction runoff control
Pollution prevention/good housekeeping

In addition, the Massachusetts Wetlands Protection Act and Stormwater Management Policy are enforced by local conservation commissions in and near jurisdictional wetlands. In some communities, local codes such as zoning, subdivision rules and regulations, and board of health regulations may also regulate stormwater discharges.

A municipal stormwater bylaw or set of bylaws is designed to create a single set of standards and a single “stormwater authority” to streamline permitting and encourage environmentally sensitive “low impact” development (LID). Many communities in Massachusetts have adopted stormwater or LID bylaws and regulations, based on a variety of widely available “model bylaws.” These bylaws typically address at least one of three MS4 program elements: illicit discharge detection and elimination; construction site runoff control; and/or post-construction runoff control. To comprehensively address stormwater, town bylaws should address all three.

Local Examples

Many communities in the Ipswich River watershed are acting to address stormwater. The towns of Boxford, Hamilton, and Ipswich are currently developing stormwater bylaws. In 2005, Topsfield used Smart Growth Technical Assistance Grant funds awarded by the Massachusetts Executive Office of Environmental Affairs to develop a stormwater management and erosion control general bylaw that addresses both construction and post-construction runoff. The crux of the bylaw is a requirement that “new development, redevelopment and all land conversion activities maintain the after-development runoff characteristics as equal to or less than the pre-development runoff characteristics in order to reduce flooding, stream bank erosion, siltation, nonpoint source pollution, property damage, and to maintain the integrity of stream channels and aquatic habitats.” This is to be accomplished through a variety of means:

Minimum construction/alteration and post-development stormwater management standards and design criteria for runoff quantity and quality,
Design and application criteria for the construction and use of structural stormwater control facilities,
Encouragement of nonstructural stormwater water management and better site design practices, such as reducing imperious cover and preserving green space,
Providing for long-term maintenance of stormwater management structures and practices,
Provisions for adequate funding mechanism, and
Administrative procedures for submission, review, approval, or disapproval of stormwater management plans.

Topfield’s bylaw authorizes the planning board to serve as stormwater authority, adopt supporting regulations, and grant stormwater management permits (SMPs). It exempts from permit requirements activities that will alter less than 7500 square feet on slopes less than 15 percent, or less then 4,000 square feet on slopes steeper than 15 percent, as well as normal maintenance activities for agriculture and single family use.

The city of Salem has developed an innovative Stormwater and LID ordinance and regulations that not only satisfies Phase II permitting requirements, but also applies the Massachusetts stormwater management standards beyond the Wetlands Protection Act jurisdictional areas to the entire city. An accompanying Urban Stormwater Management Guidebook clearly communicates the city’s expectations to designers and contractors and expedites the review process. The ordinance and regulations have not yet been adopted by the City of Salem and are subject to change based on the legal review by both the City Solicitor and the Massachusetts Attorney General.

Elsewhere in Massachusetts, the Cape Cod Commission has developed a model Land Clearing, Grading and Specimen Tree Protection Bylaw to address loss of ground cover and soil compaction leading to increased stormwater flow and sediment runoff during the construction phase. The bylaw seeks to minimize the loss of natural vegetation and topography and to protect native trees, significant forest types, and wildlife habitat during site clearing and grading. This model bylaw has not yet been adopted in Massachusetts.

Horsley Witten Group developed a model stormwater management bylaw for the South Shore towns of Duxbury, Marshfield, and Plymouth. This bylaw and its associated regulations focus on post-construction stormwater management only. The regulations identify stormwater management criteria, including:

No untreated direct discharges to water bodies or water supply systems,
Runoff detention to attenuate peak flows from a two-year storm event, to protect channel banks from erosion,
Runoff detention to attenuate peak discharges from a ten-year storm event,
Extreme flooding protection from a 100-year storm,
Annual recharge that mimics the pre-development recharge, and
Use of structural practices that meet Massachusetts water quality standards.

Resources

Cape Cod Commission, Land Clearing, Grading and Specimen Tree Protection Bylaw (html)

Center for Watershed Protection, Stormwater Manager’s Resource Center (html)

Comprehensive Environmental Inc, Stormwater Technical Design Criteria, June 2005 (pdf)

Geosyntec, Massachusetts Nonpoint Source Pollution Management Manual (html)

Horsley Witten Group, Model Stormwater Management Bylaw and Regulations (pdf)

Massachusetts Executive Office of Environmental Affairs, Smart Growth Toolkit (html)

Massachusetts Department of Conservation and Recreation, Adoption of Local Stormwater Bylaws: Guidance for Massachusetts Municipalities with NPDES Phase II Model Stormwater Bylaws, April 2004 (doc)

Massachusetts Department of Environmental Protection, Stormwater Policies and Guidance (html)

Massachusetts Department of Environmental Protection, Stormwater Policy Handbook, March 1997