FAQs on Wetland Buffers

What does Impervious mean?
Impervious means that water cannot penetrate the ground surface - instead it flows over the surface directly into catch basins, streams, and wetlands without any reduction of the chemicals or heat carried by the water. Nonporous pavement is one example. Development in the New York City watershed in this area has created a significant amount of new impervious surface is often created by new construction and is often examined by the DEP for these reasons, including parking lots, buildings and rooftops. New home development, stores and other services are the major cause of increasing imperviousness.

What is Water Quality?
Water quality is determined by the ability of a specific water body to serve its intended use, e.g. drinking, habitat, fishing, swimming, etc. 70% of Yorktown has streams, ponds or lakes that drain into the Croton Watershed which supplies New York City with drinking water.

How does imperviousness affect the environment?
When rain water falls onto an impervious surface, it can no longer seep into the ground and be naturally filtered by vegetation and soil. Instead, the water moves over hard impervious surfaces at a much faster rate. Because the water is moving off quicker, it can overwhelm drainage ditches and streams causing flooding. As storm water travels over roads and parking lots, it also picks up pollutants such as oil, grease, bacteria and sediment. Sediment in particular captures harmful elements. These pollutants, now in the stormwater runoff, are delivered directly to streams, lakes and reservoirs.

What effects do we see from stormwater runoff of impervious areas?
The following impacts of imperviousness have been scientifically documented:

• Flooding as more water is delivered faster and more directly to water bodies without being slowed down by vegetation or absorbed into the soil.
• Erosion as stream banks are undercut and washed away due to higher and faster flows of water.
• Sedimentation due to upstream soil erosion, which is gradually filling in our lakes, harbors, bays and other water bodies.
• Water temperature increases due to heated stormwater runoff from impervious surfaces.
• Water quality degradation from increased pollution levels such as excessive phosphates and pathogens.
• Habitat loss of certain fish and wildlife species due to water temperature increases, sedimentation, and nitrogen and phosphate loading.

What is a riparian buffer?
A riparian buffer is a streamside or wetland buffer is that strip of vegetation on the banks of a stream or wetland and it moderates the temperature of water after it runs off impervious surfaces such as hot pavement or rooftops, and also the buffer filters out excessive nutrients and other nonpoint source pollutants (like fertilizer, pesticides, or animal waste pathogens). Buffers also slow down the speed of the runoff which helps stabilize streambanks and alleviates flooding. Buffers are an important source of wildlife habitat diversity and providee leaf litter for animals at the bottom of th efood chain A riparian buffer has three distinct zones:

• Streamside Zone A minimum of 25 feet wide This is the zone closest to the stream or wetland and it protects the physical and ecological integrity of the stream and wetland. Activities should be highly retricted in this area.
• Middle Core A minimum of 50 feet wide, this zone borders the streamside zone. This zone can incorporate passive recreation (such as hiking trails) and certain stormwater management practices.
• A minimum of 25 feet wide, this is the buffer's buffer, which may support turf but preferably native shrubs and trees which are more effective at removing poillutants or heat from stormwater runoff.
• For more information visit the USDA's website on buffers at USDA Natural Resources Conservation Service.

How can we reverse the negative impacts of urban sprawl and imperviousness?
There are some easy ways to alleviate the impacts of imperviousness:

• Divert roof gutters onto vegetated areas instead of paved surfaces or pipes.
• Minimize the amount of impervious area (e.g. driveways, parking lots, roads, patios, etc.) or use pervious materials.
• Plant trees and shrubs to minimize surface runoff. Create natural buffer areas around wetlands, ponds and streams by creating a "no-mow" vegetated zone that filters runoff.
• Use paving surfaces that allow rainwater to soak into the ground, i.e. wood decking, bricks, or interlocking stones or porous asphalt for driveways.
• Select native plants and trees that grow naturally in this area and are not exotic imported plants that may overwhelm a site, such as phragmites. Phragmites is that 8' high grass which grows in wet disturbed areas everywhere and displaces cat-o-nine tails, which muskrats like to eat. Instead - put in plants that don't need a great deal of water or fertilizer to survive.
• Use fertilizers, herbicides and pesticides sparingly (or not at all) and according to directions.
• Use car washes that treat and recycle the wastewater. Wash your car on the lawn, instead of over asphalt. Check automobiles for leaking oil and other fluids and make repairs, if needed.
• Pick up and properly dispose of pet waste. Biological waste can not only add nutrients, but bacteria to water bodies and create algal blooms that can reduce oxygen levels in water when they decompose killing fish and producing odors.