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Low Impact Development & Nonpoint Source Pollution

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Presentation on theme: "Low Impact Development & Nonpoint Source Pollution"— Presentation transcript:

1 Low Impact Development & Nonpoint Source Pollution

2 Define Low Impact Development
LID is an approach to land development (or re-development) that works with nature to manage storm water as close to its source as possible. LID employs principles such as preserving and recreating natural landscape features, minimizing effective imperviousness to create functional and appealing site drainage that treat storm water as a resource rather than a waste product. There are many practices that have been used to adhere to these principles such as bioretention facilities, rain gardens, vegetated rooftops, rain barrels, and permeable pavements. By implementing LID principles and practices, water can be managed in a way that reduces the impact of built areas and promotes the natural movement of water within an ecosystem or watershed. Applied on a broad scale, LID can maintain or restore a watershed's hydrologic and ecological functions.

3 Nonpoint Source Pollution
Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas Oil, grease, and toxic chemicals from urban runoff and energy production Sediment from improperly managed construction sites, crop and forest lands, and eroding stream banks Salt from irrigation practices and acid drainage from abandoned mines Bacteria and nutrients from livestock, pet waste, and faulty septic systems Atmospheric deposition and hydromodification

4 Nonpoint Source Pollution cont.
Comes from many diffuse sources such as rainfall or snowmelt moving over and through the ground Results from land runoff, precipitation, atmospheric deposition, drainage, seepage, or hydrologic modification

5 Impacts of land use on watersheds
Land uses from any part of the watershed -- such as polluted runoff from farms, forests and homes -- eventually affect the health of the whole watershed. Land use practices such as clearing land for timber or agriculture, developing and maintaining roads, housing developments, and water diversions may have environmental consequences that greatly affect stream conditions even when the activity is not directly associated with or near a stream. Proper planning and adequate care in implementing projects can help ensure that one activity within a watershed does not detrimentally impact the downstream environment.

6 In a healthy watershed, after a rain event, vegetation and wetlands intercept and slow the flow of water as it travels through the watershed, removing sediment and allowing large quantities of water to enter the soil and percolate into the groundwater. This groundwater is then available to contribute to late season stream flow, to the benefit of fisheries and water quality. In comparison, a watershed with more impervious surfaces and the loss of vegetation and wetlands, responds differently after a rain event. More water runs over the land instead of replenishing groundwater. This larger volume of water quickly reaches water bodies reducing the time available for the water to be cleansed and filtered and also causing erosion of stream banks.

7 Most human activities and development have the potential to adversely affect the overall health and quality of a watershed. Timber harvest on unstable slopes can cause erosion. Agricultural activities can increase levels of harmful bacteria and overload runoff with nutrients. Also, poorly planned urban and industrial growth can cause many of the same problems as farming and timber harvest in addition to contamination from toxic chemicals. Even seemingly harmless activities such as rural development and recreational activities along rivers and creeks can be harmful, impacting the watershed's sensitive riparian vegetation which is important for water quality protection and wildlife habitat.

8 When viewed individually, most human activities have little effect on the general health of the watershed. However, the effects of numerous activities within a watershed are cumulative and when combined can greatly diminish the watershed's overall health. Every activity has the potential to impact the area of the watershed downstream. As people place more demands on a watershed, greater efforts must be made to reduce these cumulative effects. Having clean water will require communities to work together to ensure that activities do not negatively impact those downstream.

9 In the 2000 National Water Quality Inventory, states reported that agricultural nonpoint source (NPS) pollution is the leading source of water quality impacts on surveyed rivers and lakes, the second largest source of impairments to wetlands, and a major contributor to contamination of surveyed estuaries and ground water. Agricultural activities that cause NPS pollution include poorly located or managed animal feeding operations; overgrazing; plowing too often or at the wrong time; and improper, excessive, or poorly timed application of pesticides, irrigation water, and fertilizer. Pollutants that result from farming and ranching include sediment, nutrients, pathogens, pesticides, metals, and salts. Impacts from agricultural activities on surface water and ground water can be minimized by using management practices that are adapted to local conditions. Many practices designed to reduce pollution also increase productivity and save farmers and ranchers money in the long run.

10 Did you know that runoff from farms is the leading source of impairments to surveyed rivers and lakes? There are many government programs available to help farmers and ranchers design and pay for management approaches to prevent and control NPS pollution. For example, over 40 percent of section 319 Clean Water Act grants have been used to control NPS pollution from working farms and ranches. Also, many programs funded by the U.S. Department of Agriculture and by states provide cost-share, technical assistance, and economic incentives to implement NPS pollution management practices. Many local organizations and individuals have come together to help create regional support networks to adopt technologies and practices to eliminate or reduce water quality impacts caused by agricultural activities.

11 Conventional Development vs. LID:
Conventional development techniques often clear all trees and valuable topsoil from a site and re-grade it so that all water ends up in one large detention basin. Resulting problems include loss of recharge, increased water temperature, decreased water quality and higher runoff volumes. The LID approach protects the natural ability of the site to capture precipitation, keep it clean and allow it to recharge the local water table.


13 LID Best Management Practices and selection criteria
The use of best management practices to reduce the amount of impervious surfaces, disconnect flow paths (i.e., downspouts connected to storm sewers), and treat storm water at its source all help minimize the impacts to water quality and local hydrology.

14 Pro’s of applying LID Provides energy at an affordable cost
Minimizes land clearing and grading costs Reduces infrastructure costs (streets, curbs, gutters, sidewalk) Reduces storm water management costs (reduces or eliminates storm sewers and ponds) Increases lot and community marketability Increases lot sale yields and reduces permit fees

15 Pro’s cont. Protects site and regional water quality by reducing sediment, nutrient, and toxic loads to water bodies Balances growth needs with natural resource protection Reduces municipal infrastructure and utility maintenance costs (streets, curbs, gutters, sidewalks, storm sewers and ponds) Fosters public/private partnerships Provides local accessibility to open spaces, recreation and wildlife areas Preserves and protects amenities that can translate into more saleable homes and communities Provides shading for homes and properly orients homes to help decrease monthly utility bills

16 Pro’s cont. Preserves integrity of ecological and biological systems
Protects site and regional water quality by reducing sediment, nutrient, and toxic loads to water bodies Reduces impacts to local terrestrial and aquatic plants and animals Preserves trees and natural vegetation Creates connected corridors of wildlife habitat

17 Con’s Supplies have to be specially ordered
Not significantly different compared to what we already have Not well known People refuse to use it.

18 Hydrologic Controls Clustering buildings Building set backs
Naturally vegetated buffers Natural vegetation should be preserved Steep slopes should not be disturbed Rain gardens Bio retention areas Grassed swales Native plant landscaping

19 Hydrologic Controls Permeable or porous pavement
Reduced in impervious surfaces Disconnected down spouts (Rain barrels) Green roofs

20 Rain Garden Green roof system

21 What can communities do?
Start using LID for community building/municipal center Make laws to enforce LID Promote LID Encourage others to use LID Reach out to developers Get projects on the ground Make sure ordinances are LID friendly Use less pavement

22 Soils, wildlife, forestry, and aquatics affect and are affected by nonpoint source pollution and its reduction and LID Polluted storm water runoff can have many adverse effects on plants, fish, animals, and people. Sediment can cloud the water and make it difficult or impossible for aquatic plants to grow. Sediment also can destroy aquatic habitats Excess nutrients can cause algae blooms. When algae die, they sink to the bottom and decompose in a process that removes oxygen from the water. Fish and other aquatic organisms can’t exist in water with low dissolved oxygen levels. Bacteria and other pathogens can wash into swimming areas and create health hazards, often making beach closures necessary.


24 Debris—plastic bags, six-pack rings, bottles, and cigarette butts—washed into water bodies can choke, suffocate, or disable aquatic life like ducks, fish, turtles, and birds. Household hazardous wastes like insecticides, pesticides, paint, solvents, used motor oil, and other auto fluids can poison aquatic life. Land animals and people can become sick or die from eating diseased fish and shellfish or ingesting polluted water. Polluted storm water often affects drinking water sources. This, in turn, can affect human health and increase drinking water treatment costs.

25 Auto care Washing your car and degreasing auto parts at home can send detergents and other contaminants through the storm sewer system. Dumping automotive fluids into storm drains has the same result as dumping the materials directly into a water body.

26 Lawn care Excess fertilizers and pesticides applied to lawns and gardens wash off and pollute streams. In addition, yard clippings and leaves can wash into storm drains and contribute nutrients and organic matter to streams.

27 Septic Systems Leaking and poorly maintained septic systems release nutrients and pathogens (bacteria and viruses) that can be picked up by storm water and discharged into nearby water bodies. Pathogens can cause public health problems and environmental concerns.

28 Pet waste Pet waste can be a major source of bacteria and excess nutrients in local waters.

29 Dirt, oil, and debris that collect in parking lots and paved areas can be washed into the storm sewer system and eventually enter local water bodies. Erosion controls that aren’t maintained can cause excessive amounts of sediment and debris to be carried into the storm water system. Construction vehicles can leak fuel, oil, and other harmful fluids that can be picked up by storm water and deposited into local water bodies.

30 Improperly managed logging operations can result in erosion and sedimentation.
Uncovered fueling stations allow spills to be washed into storm drains. Cars waiting to be repaired can leak fuel, oil, and other harmful fluids that can be picked up by storm water.

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