Introduction [ Top ]
The Town of Lewisboro has developed a Stormwater Management Program to help improve our management of stormwater. Natural resources are an important component of the quality of life in Lewisboro. The landscape around us is important for its scenic aspects, and also because it affects our groundwater. The quality of our wetlands can affect the quality of our drinking water and of our ability to enjoy the land, lakes, reservoirs, and streams around us. To help manage the impacts of stormwater on our environment, the Lewisboro Stormwater Management Committee was formed in September, 2007.
What is Stormwater [Index]
Stormwater is water from rain or melting snow that doesn't soak into the ground but runs off into waterways. It flows from rooftops, over paved areas and bare soil, and through sloped lawns while picking Index a variety of materials on its way. As it flows, stormwater runoff collects and transports soil, animal waste, salt, pesticides, fertilizers, oil and grease, debris and other potential pollutants. The quality of runoff is affected by a variety of factors and depends on the season, local meteorology, geography and Indexon activities which lie in the path of the flow.
Why is stormwater important
(definition from the NYS DEC web site)
Stormwater from a rain event or melting snow can pick Index and move sediment and a variety of pollutants. Because the stormwater transports whatever is left on our lawns and roads, individual actions make a difference in determining the kinds and amounts of pollution.
In more developed areas, there is a greater percentage of impervious surfaces, and therefore more stormwater, and with more water, more pollutants can be transported. In addition, the kind of surface can affect the quality and quantity of stormwater. Forested areas retain more water than lawns: lawns retain more water than bare soil.
Uncontrolled erosion and stormwater can result in increased water runoff volume, increased rate of water runoff, soil movement and sediment accumulation which can damage our stormwater conveyance system of streams, brooks, swales, wetlands and waterbodies. This damages results in the destruction of habitat, accelerated lake degradation, increased pollutant loading and greater increase in the occurrence and impacts of flooding.
Polluted runoff degrades our lakes, rivers, wetland and other waterways and can then get into our groundwater.
- Transported sediment clouds the waterways and interferes with the habitat of fish and plant life. Sediment often comes from construction activities or areas of erosion.
- Nutrients such as phosphorus and nitrogen can promote the overgrowth of algae, can deplete oxygen in the waterways, can be harmful to other aquatic life and can alter the habitat ecology.
- Toxic chemicals from automobiles and home supplies, and the careless application of pesticides, herbicides and fertilizers all threaten the health of the receiving waterways and can kill fish and other aquatic life.
- Bacteria from animal wastes and illicit connections to sewerage systems can make nearby lakes and streams unsafe for wading, swimming and use as drinking water supplies.
A large portion of the Town of Lewisboro is located in the NYC watershed in which the main pollutant of concern is phosphorus.
In Lewisboro, all of our stormwater runoff eventually goes into someone’s drinking water supply.
What's being done?
Lewisboro’s surface water, although a part of its natural beauty, is also largely a result of human action. The Cross River Reservoir and Muscoot Reservoir are components of the New York City drinking water system. Scotts Reservoir and Browns Reservoir, in southeast Lewisboro, are part of the drinking water supply for Connecticut residents. While Lakes Waccabuc, Oscaleta, and Rippowam are natural, Lakes Katonah, Kitchawan, Truesdale, and Timber are all manmade. In addition, the Town is laced with streams, creeks, and many small ponds. Clean surface water enhances property values and aesthetic values, provides recreation opportunities, and protects the drinking water supply.
Across the nation, attention has shifted to distributed or “nonpoint” sources of pollution such as stormwater runoff. According to an inventory conducted by the United States Environmental Protection Agency (EPA), half of the impaired waterways are affected by urban, suburban, and construction sources of stormwater runoff. Stormwater presents new challenges in water management and minimizing pollution.
Stormwater runoff normally is not treated by sewage and wastewater treatment plants. More often than not, end-of-pipe controls are not the best answer for removing pollutants from stormwater runoff. The best means of control is usually at the pollutant's source. Proper storage of chemicals, good housekeeping and just plain paying attention to what's happening during runoff events can lead to relatively inexpensive ways of preventing pollutants from getting into the runoff and then being transported to our groundwater, wetlands, and waterways.
Stormwater management practices are used to delay, collect, store, treat, or infiltrate stormwater runoff. While specific design objectives for stormwater management practices are often unique to each watershed, the general goals for stormwater management practices usually include the following:
- Maintain groundwater recharge and quality
- Reduce stormwater pollutant loads
- Protect stream channels from erosion
- Prevent increased overbank flooding
- Safely slow the velocity and carrying capacity of stormwater
The Phase II Stormwater regulations require towns like Lewisboro to implement programs and practices to control polluted stormwater runoff. These have six minimum measures:
- Public education and outreach on stormwater
- Public involvement and participation
- Illicit discharge detection and elimination
- Construction site stormwater runoff control
- Post construction stormwater management in new development and redevelopment
- Pollution prevention and good housekeeping for town operations
In December, 2007, Lewisboro passed two stormwater ordinances. One addresses the illicit discharge of stormwater, and its detection, and elimination, and the other addresses stormwater management and sediment and erosion control. These two ordinances can be read by clicking on the links at the top of this page.
In addition, you can see the actions that Lewisboro has taken by reviewing the annual reports, also linked to in the resource section below.
Resources for additional information recommended [Index]
Please be advised that the updated NYS Stormwater Management Design Manual is now posted on the following Department webpage:
http://www.dec.ny.gov/chemical/29072.html. The official release of the updated Design Manual is noticed in the August 4, 2010 Environmental News Bulletin (ENB) (see notice below).
As required by Part III.B.2 of the SPDES General Permit for Stormwater Discharges from Construction Activity (GP-0-10-001), an owner or operator of a construction project must begin using the revised version of the Design Manual to prepare their SWPPP six (6) months from the final revision date (August 2010) of the Design Manual.
For projects that are currently in the planning, design or review stages, the owner (or their design professional) should strongly consider using the updated version of the Design Manual to prepare their SWPPP (or update their SWPPP) if they do not feel that they can get all other required project approvals, develop the final SWPPP and submit a completed Notice of Intent by the end of February, 2011.
New York State Stormwater Management Design Manual (August 2010) The New York State Department of Environmental Conservation (NYS DEC) has updated theNew York State Stormwater Management Design Manual (Design Manual). The official release date of the Design Manual is August 4, 2010.
The draft updates to the Design Manual were public noticed in the Environmental Notice Bulletin from November 11, 2009 through February 03, 2010. Seven chapters of the Design Manual were re-evaluated to address public comments and are finalized as follows:
· Chapter 1 - Introduction
· Chapter 2 - Impacts of New Development
· Chapter 3 - Stormwater Management Planning
· Chapter 4 - Unified Stormwater Sizing Criteria
· Chapter 9 - Redevelopment Projects
· Chapter 5 - Green Infrastructure Practices
· Chapter 10 - Enhanced Phosphorus Removal Standards Glossary
All the Chapters are available at:
For assistance with the electronic files, please contact Barbara Horton at 518-402-8111.
Hard copies the Design Manual will be available for order through the Empire State Chapter of the Soil and Water Conservation Society at:
Contact: Shohreh Karimipour, David Gasper, NYS DEC - Division of Water, Bureau of Water Permits, 625 Broadway, Albany, New York 12233-3505,
Phone: (518)402-8111, Fax: (518)402-9029.