How Development Impacts Harbor Water Quality Urbanization and development change the physical landscape, degrading Stonington harbors by reducing the amount of land available to absorb and filter rain.  Impervious surfaces, that do not allow fluid to pass through, result from paving, sidewalks, driveways, compacted soils, and buildings.  They speed the flow of water into streams or drains that often empty directly, without filtration, into wetlands or harbors, carrying pollutants such as road oil, lawn and garden chemicals, construction substances, or trash.   Watersheds and wetlands slow runoff, act as a filtration system, and provide habitat that assures the continued health of an aquatic body and its biological community.  A 2001 study from the University of Maine identified a threshold for development in watershed areas.  When the level of watershed imperviousness exceeds 6-10%, water quality and its ability to support fish and marine life becomes degraded.   A typical house, garage, and driveway on a one acre lot would have a 5-12% impervious area.  Protection of water resources does not depend on the density of each acre itself but the overall percentage of imperviousness in a watershed.  Stonington currently has a great deal of undeveloped open space, and it is important to protect it, especially in watershed and wetland areas, because development is seldom reversible.   For aquatic protection landscape alternations must protect existing marshlands and be designed to slow runoff of water, maximize filtration, and prevent erosion of soils.  Yet grading, paving, and filling for development is often done specifically to increase water runoff, diverting it away from buildings, at the same time removing trees, native grass, and vegetation that intercepts and absorbs it.   Heavy development along wetlands - like the Stonington Route #1 corridor proposed for sewers and utilities - has been shown to increase the risk and seriousness of flooding.  From the early 1900's to the year 2000, flood damages in the United States increased about 600% due to urbanization, costing $6 billion annually in spite of other billions spent on flood controls.   As illustrated by Hurricane Katrina's impact on New Orleans, building in marshy, low lands, a common practice when business required water for transportation, makes no sense today.   Encouraging development on wetlands will not only degrade harbor water quality, it sets up future economic hardship for the increased number of businesses and residents likely to be flooded.  It adds to the burden of taxpayers who fund both installing the utilities to enable such growth and disaster bailouts after massive flooding.  Stonington taxpayers have consistently expressed support for the homes and businesses currently along the Route #1 corridor but are wisely opposed to further expansion.  To actively promote increased development in this watershed and wetland area represents short-term planning and thinking, common in the past.   Development and growth are a natural part of a healthy community, but there are places and practices that make it a sound long-term investment.  Poorly planned communities feature urban `sprawl' with unsightly strip malls along every highly traveled road; heavy traffic and more lights that slow and control it; and little thought for esthetics, the environment, or the future.  Such an approach is rapidly changing, however.  From Puget Sound in Washington to Long Island Sound communities, Low Impact Development (called LID in planner jargon) is the new watchword.   Low Impact Development lessens the environmental risks by integrating a site's existing features with practices that mimic natural hydrology, allowing water to infiltrate into the ground instead of flowing off hard surfaces directly into local waterways.  It incorporates retaining native soil and vegetation, using natural small-scale hydrologic controls that slow, store, and filtrate storm water.  Rain gardens, green roofs, and pervious paving are other techniques.  All protect water quality, fish, wildlife habitat, and natural ecosystems by reducing sediment, nutrient runoff, and toxic loads in waterways.    LID does not include building in marshy bogs, wetlands, or flood plains, especially given rising ocean levels and increased coastal flooding.