Eight Tools of Watershed Protection

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  • This presentation outlines a watershed protection approach that applies eight tools to protect or restore aquatic resources in a subwatershed. It describes the nature and purpose of the eight watershed protection tools, outlines some specific techniques for applying the tools, and highlights some key choices a watershed manager should consider when applying or adapting the tools within a given subwatershed.
  • Eight Tools of Watershed Protection

    1. 1. Introduction to the Eight Tools of Watershed Protection Presented by:
    2. 2. 1. Land Use
    3. 3. LAND USE
    4. 4. Preparing a Land Use Plan <ul><li>When preparing a land use plan, a watershed manager needs to: </li></ul><ul><li>Predict what will happen to water resources with future land use changes. </li></ul><ul><li>Obtain consensus on the most important water resource goals in the watershed. </li></ul><ul><li>Develop a future land use pattern for the subwatersheds that can meet those goals. </li></ul><ul><li>Select the most acceptable and effective land use planning techniques to reduce or shift impervious cover. </li></ul><ul><li>Select the most appropriate combination of other watershed protection tools to apply to individual subwatersheds. </li></ul><ul><li>Devise an ongoing management structure to adopt and implement the watershed plan. </li></ul>
    5. 5. Copyright 1999, Center for Watershed Protection This graph illustrates the relationship between impervious cover and stream quality, information that can be used to categorize streams as sensitive , impacted , or non-supporting .
    6. 6. This is an example of a Montgomery County, MD land use planning map that classifies subwatersheds based on an impervious cover model.
    7. 7. Land Use Planning Techniques <ul><li>Watershed Base Zoning </li></ul><ul><li>Overlay Zoning </li></ul><ul><li>Floating Zones </li></ul><ul><li>Incentive Zoning </li></ul><ul><li>Performance Zoning </li></ul><ul><li>Urban Growth Boundaries </li></ul><ul><li>Large Lot Zoning </li></ul><ul><li>Infill Community Redevelopment </li></ul><ul><li>Transfer of Development Rights </li></ul>
    8. 8. This is another example of a watershed-based zoning map that uses impervious cover to categorize subwatersheds in Montgomery County, MD. Copyright 1999, Center for Watershed Protection
    9. 9. Watershed-based Zoning 1. Stream Inventory 2. Measure impervious cover 3. Verify impervious cover/ stream quality relationships 4. Project future levels of impervious cover 5. Classify subwatersheds 6. Modify master plans/zoning to correspond 7. Incorporate management priorities from larger watershed units 8. Adopt specific watershed protection strategies 9. Long term monitoring
    10. 10. This is a map of a barrier island which would benefit from zoning measures to protect its resources.
    11. 11. By using overlay zoning, the same barrier island and its resources can be protected.
    12. 12. Criteria for Urban Growth Boundaries <ul><li>Provide nearby public facilities and services </li></ul><ul><li>Provide a sufficient amount of land to meet projected </li></ul><ul><li>growth </li></ul><ul><li>Provide a mix of land uses </li></ul><ul><li>Analyze the impact of growth on natural resources </li></ul><ul><li>Boundary criteria should be fair and include natural </li></ul><ul><li>resources </li></ul>
    13. 13. Other Land Use Planning Techniques <ul><li>Large Lot Zoning </li></ul><ul><li>Infill/Community Redevelopment </li></ul><ul><li>Transfer of Development Rights ( TDRs ) </li></ul>
    14. 14. Key Land Use Planning Choices for the Watershed Manager <ul><li>What are the most acceptable land use planning </li></ul><ul><li>techniques that can be used to shift/reduce </li></ul><ul><li>impervious cover? </li></ul><ul><li>How accurate are the estimates of future impervious </li></ul><ul><li>cover? </li></ul><ul><li>What are the future impacts of impervious cover ? </li></ul><ul><li>Which subwatersheds are capable of absorbing future </li></ul><ul><li>impervious cover? </li></ul>
    15. 16. Tool #2: Land Conservation <ul><li>Five types of land may need to be conserved in a subwatershed: </li></ul><ul><li>Critical habitats </li></ul><ul><li>Aquatic corridor </li></ul><ul><li>Hydrologic reserve area </li></ul><ul><li>Water pollution hazards </li></ul><ul><li>Cultural areas </li></ul>
    16. 17. Conservation Area: Critical Habitat <ul><li>Description: essential spaces for plant and animal communities </li></ul><ul><li>Tidal wetlands </li></ul><ul><li>Freshwater wetlands </li></ul><ul><li>Large forest clumps </li></ul><ul><li>Springs </li></ul><ul><li>Spawning areas </li></ul><ul><li>Habitat for rare or endangered species </li></ul><ul><li>Potential restoration sites </li></ul><ul><li>Native vegetation areas </li></ul><ul><li>Coves </li></ul>
    17. 18. Tidal wetland s are considered critical habitat and provide essential spaces for plant and animal communities. Photo Copyright 1999, Center for Watershed Protection
    18. 19. Freshwater areas like this are also considered critical habitat since they provide spawning areas for trout. Photo Copyright 1999, Center for Watershed Protection
    19. 20. Conservation Area: Aquatic Corridor <ul><li>Description: Area where land and water interact </li></ul><ul><li>Floodplains </li></ul><ul><li>Stream channels </li></ul><ul><li>Springs and seeps </li></ul><ul><li>Steep slopes </li></ul><ul><li>Small estuarine coves </li></ul><ul><li>Littoral areas </li></ul><ul><li>Stream crossing </li></ul><ul><li>Shorelines </li></ul><ul><li>Riparian forest </li></ul><ul><li>Caves </li></ul><ul><li>Sinkholes </li></ul>
    20. 21. The aquatic corridor is comprised of the stream and its rights-of-way. Healthy stream channels diverge, converge, and meander along the natural stream path. Photo Copyright 1999, Center for Watershed Protection
    21. 22. <ul><li>Description: Undeveloped areas that maintain the pre-development hydrologic response of a subwatershed: </li></ul><ul><li>Forest </li></ul><ul><li>Meadow </li></ul><ul><li>Prairie </li></ul><ul><li>Wetland </li></ul><ul><li>Crop </li></ul><ul><li>Pasture </li></ul><ul><li>Managed forest </li></ul>Conservation Area: Hydrologic Reserve
    22. 23. This aerial photo shows several types of land uses, including crops, forests, and pastures, that can function as hydrologic reserves. Photo Copyright 1999, Center for Watershed Protection
    23. 24. Forests are important conservation areas because they can help maintain the pre-development hydrologic response of a subwatershed. Photo Copyright 1999, Center for Watershed Protection
    24. 25. <ul><li>Septic systems </li></ul><ul><li>Landfills </li></ul><ul><li>Hazardous waste generators </li></ul><ul><li>Above/below ground tanks </li></ul><ul><li>Impervious cover </li></ul><ul><li>Surface/subsurface discharge of wastewater effluent </li></ul>Conservation Area: Water Pollution Hazard <ul><li>Land application sites </li></ul><ul><li>Stormwater “hotspots ” </li></ul><ul><li>Pesticide application areas </li></ul><ul><li>Industrial sites </li></ul><ul><li>Road salt storage areas </li></ul><ul><li>Water supply intakes </li></ul>Description: Land use or activity that creates a greater risk of potential water pollution
    25. 26. Hazardous wastes left in areas not designated for proper collection can create “stormwater hotspots.” Photo Copyright 1999, Center for Watershed Protection
    26. 27. Facilities that may be potential pollutant sources are often kept a designated distance away from streams, rivers, and other water bodies. Photo Copyright 1999, Center for Watershed Protection
    27. 28. <ul><li>Description: Areas that provide a sense of our place in the landscape: </li></ul><ul><li>Historic and archaeological sites </li></ul><ul><li>Trails </li></ul><ul><li>Parkland </li></ul><ul><li>Scenic views </li></ul><ul><li>Water access </li></ul><ul><li>Bridges </li></ul><ul><li>Recreational areas </li></ul>Conservation Area: Cultural Areas
    28. 29. Historic sites such as the one shown here in historic Ellicott City, MD are not only aesthetic and educational but provide a sense of community as well. Photo Copyright 1999, Center for Watershed Protection
    29. 30. Pullovers are provided off the George Washington Parkway so that the public can enjoy the scenic overlook. Photo Copyright 1999, Center for Watershed Protection
    30. 31. This trail which runs alongside the Choptank River in Maryland provides the public with a form of recreation and access to the water. Photo Copyright 1999, Center for Watershed Protection
    31. 32. The numerous docks in Annapolis provide recreational access to the water, which can promote public appreciation for water resources. Photo Copyright 1999, Center for Watershed Protection
    32. 33. <ul><li>Land Acquisition </li></ul><ul><li>Conservation Easements </li></ul><ul><li>Regulation of Land Alteration </li></ul><ul><li>Exclusion or Setbacks of Water Pollution Hazards </li></ul><ul><li>Protection Within Open Space Designs </li></ul><ul><li>Landowner Stewardship </li></ul><ul><li>Public Sector Stewardship </li></ul>Land Conservation Techniques
    33. 34. Key Land Conservation Choices for the Watershed Manager <ul><li>What fraction of the watershed needs to be conserved? </li></ul><ul><li>What are the highest priorities for land conservation? </li></ul><ul><li>How will long-term management be handled? </li></ul><ul><li>What incentives can be used to encourage stewardship of </li></ul><ul><li>private lands? </li></ul><ul><li>Does a land trust exist to accept and manage conservation </li></ul><ul><li>areas? </li></ul><ul><li>What are the most appropriate techniques to conserve </li></ul><ul><li>land? </li></ul><ul><li>How should conservation areas be delineated? </li></ul>
    34. 36. This buffer was reestablished with great success in Anacostia near Washington, DC. After only two growing seasons, the vegetation showed dramatic recovery growth. Photo Copyright 1999, Center for Watershed Protection
    35. 37. Benefits of Aquatic Buffers <ul><li>Regulates light and temperature conditions, improving the habitat for aquatic plants and animals </li></ul><ul><li>Effective in removing sediment, nutrients, and bacteria from stormwater and groundwater </li></ul><ul><li>Helps to stabilize and protect the streambank </li></ul>
    36. 39. This development in Howard County, MD illustrates a buffer. The outer zones consist of backyards where usage is unrestricted and the vegetative target can be turf grass. Photo Copyright 1999, Center for Watershed Protection
    37. 40. This tree preservation area is clearly marked throughout the construction stage to prevent clearing. Photo Copyright 1999, Center for Watershed Protection
    38. 41. Key Buffer Choices for the Watershed Manager <ul><li>How much of the aquatic corridor can be </li></ul><ul><li>protected by buffers? </li></ul><ul><li>How should buffers be managed and crossed? </li></ul><ul><li>Is restoration or better stewardship possible </li></ul><ul><li>along an aquatic corridor that has already been </li></ul><ul><li>developed? </li></ul><ul><li>How will the buffer network be managed? </li></ul><ul><li>Long-term maintenance? </li></ul><ul><li>How much pollutant removal is to be expected by </li></ul><ul><li>the buffer network? </li></ul>
    39. 43. A typical conventional site contains huge areas of impervious cover that can potentially be reduced. Photo Copyright 1999, Center for Watershed Protection
    40. 44. Typical streets are often excessively wide, increasing traffic speeds and making streets unfriendly to pedestrians. Photo Copyright 1999, Center for Watershed Protection
    41. 45. Typical cul-de-sacs are often large enough to double as spaceship landing pads. Photo Copyright 1999, Center for Watershed Protection
    42. 46. This conceptual plan utilizes several better site design techniques, including a vegetated island that allows stormwater filtration, shorter driveways, narrow streets, and alternate pavement for overflow parking.
    43. 47. Better Site Design <ul><li>Three Categories: </li></ul><ul><li>Residential Streets and Parking Lots </li></ul><ul><li>Lot Development </li></ul><ul><li>Conservation of Natural Areas </li></ul>
    44. 48. Parking lots are often underutilized and can be minimized through better site design techniques. Photo Copyright 1999, Center for Watershed Protection
    45. 49. This example of an open space design utilizes the existing character of the area by minimizing clearing and grading and preserving large tracts of natural open space.
    46. 50. Key Site Design Choices for the Watershed Manager <ul><li>Will better site design reduce the amount of </li></ul><ul><li>impervious cover in my subwatershed? </li></ul><ul><li>What are the most important development rules </li></ul><ul><li>that need to be changed to promote better site </li></ul><ul><li>design? </li></ul><ul><li>What incentives can be used to encourage </li></ul><ul><li>developers to utilize better site design? </li></ul><ul><li>What is the time frame for revising codes and </li></ul><ul><li>ordinances? </li></ul>
    47. 52. Clearing and grading of the entire site, and all at once, is a common construction practice. Some state regulations require exposed soils to be stabilized within 7 - 10 days. Photo Copyright 1999, Center for Watershed Protection
    48. 53. Ten Elements of an Effective ESC Plan 1. Minimize Needless Clearing and Grading 2. Protect Waterways and Stabilize Drainage Ways 3. Phase Construction to Limit Soil Exposure 4. Stabilize Exposed Soils Immediately 5. Protect Steep Slopes and Cuts 6. Install Perimeter Controls to Filter Sediments 7. Employ Advanced Sediment Settling Controls 8. Certify Contractors on ESC Plan Implementation 9. Adjust ESC Plan at Construction Site 10. Assess ESC Practices After Storms
    49. 54. The use of straw is one technique for stabilizing soils. Photo Copyright 1999, Center for Watershed Protection
    50. 55. This sedimentation basin was constructed to treat the erosion from the construction right in the background. However, the basin is not being maintained properly and the heavy sedimentation is a sign of failure. Photo Copyright 1999, Center for Watershed Protection
    51. 56. Silt fences are another ESC measure, but are worthless without proper installation and maintenance. Photo Copyright 1999, Center for Watershed Protection
    52. 57. Key Erosion and Sediment Control Choices for the Watershed Manager <ul><li>Is a higher level of ESC practice or more frequent </li></ul><ul><li>inspection needed to protect my subwatershed? </li></ul><ul><li>How well do current ESC programs reinforce </li></ul><ul><li>other watershed protection tools? </li></ul><ul><li>What incentives can be used to minimize the </li></ul><ul><li>amount of clearing at development sites? </li></ul>
    53. 59. Goals of Stormwater BMPs <ul><li>Maintain groundwater recharge and quality </li></ul><ul><li>Reduce stormwater pollutant loads </li></ul><ul><li>Protect stream channels </li></ul><ul><li>Prevent increased overbank flooding </li></ul><ul><li>Safely convey extreme floods </li></ul>
    54. 60. Best Management Practices <ul><li>Most stormwater BMPs can be grouped into five general categories: </li></ul><ul><li>Ponds </li></ul><ul><li>Wetlands </li></ul><ul><li>Infiltration </li></ul><ul><li>Filtering systems </li></ul><ul><li>Open channels </li></ul>
    55. 61. Stormwater wet ponds are characterized by a permanent pool of water. Photo Copyright 1999, Center for Watershed Protection
    56. 62. Stormwater wetlands treat the stormwater for both quality and quantity. Photo Copyright 1999, Center for Watershed Protection
    57. 63. Infiltration trenches allow stormwater to percolate slowly into the soil. Photo Copyright 1999, Center for Watershed Protection
    58. 64. Bioretention areas are a type of filtering system often used in parking lots. Photo Copyright 1999, Center for Watershed Protection
    59. 65. Open channels are often used along roadways to convey and infiltrate stormwater. Photo Copyright 1999, Center for Watershed Protection
    60. 66. Key Stormwater Choices for the Watershed Manager <ul><li>Determine the most effective mix of structural and non-structural BMPs that can meet my subwatershed goals </li></ul><ul><li>Which hydrologic variables do we want to manage in the subwatershed? </li></ul><ul><li>What are the primary stormwater pollutants of concern? </li></ul><ul><li>Which BMPs should be avoided because of their environmental impacts? </li></ul><ul><li>What is the most economical way to provide stormwater management? </li></ul><ul><li>Which BMPs are the least burdensome to maintain with local budgets? </li></ul>
    61. 68. Non-Stormwater Discharges <ul><li>Septic Systems </li></ul><ul><li>Sanitary Sewers </li></ul><ul><li>Other </li></ul><ul><ul><li>Industrial NPDES discharges </li></ul></ul><ul><ul><li>Urban “return flows” </li></ul></ul><ul><ul><li>Water diversions </li></ul></ul><ul><ul><li>Runoff from confined animal feeding lots </li></ul></ul><ul><ul><li>Miscellaneous </li></ul></ul>
    62. 69. This schematic of a septic system shows how a faulty septic tank could potentially pollute groundwater.
    63. 70. Septic systems that fail or are improperly located have the potential to pollute our lakes and streams. Copyright 1999, Center for Watershed Protection
    64. 71. Illicit connections to the storm drain also pollute our waters. Photo Copyright 1999, Center for Watershed Protection
    65. 72. Runoff from animal lots can contaminate our streams without proper treatment. Photo Copyright 1999, Center for Watershed Protection
    66. 73. Key Non-Stormwater Discharge Choices for the Watershed Manager <ul><li>Can permit programs be utilized to improve compliance? </li></ul><ul><li>Does it make sense to extend the sewer envelope into the watershed? </li></ul><ul><li>Where will the sewer be located in relationship to the stream corridor? </li></ul><ul><li>Are current permits adequate? </li></ul>
    67. 75. Watershed Stewardship Programs <ul><li>Watershed Advocacy </li></ul><ul><li>Watershed Education </li></ul><ul><li>Pollution Prevention </li></ul><ul><li>Watershed Maintenance </li></ul><ul><li>Indicator Monitoring </li></ul><ul><li>Restoration </li></ul>
    68. 76. Elements of Watershed Education <ul><li>Watershed awareness </li></ul><ul><li>Personal stewardship </li></ul><ul><li>Professional training </li></ul><ul><li>Watershed engagement </li></ul>
    69. 77. The Adopt-A-Stream program provides an excellent opportunity for active public participation and education. Photo Copyright 1999, Center for Watershed Protection
    70. 78. These citizen volunteers are planting trees to help reforest a buffer. Photo Copyright 1999, Center for Watershed Protection
    71. 79. Assessing the quality and quantity of aquatic biota is one way to monitor the health of a watershed. Photo Copyright 1999, Center for Watershed Protection
    72. 80. Hydrologic gauging stations compute stream velocity and measure pollutant levels. Photo Copyright 1999, Center for Watershed Protection
    73. 81. This stream restoration project included building log drops to provide spawning habitat for salmon. Photo Copyright 1999, Center for Watershed Protection
    74. 82. Key Stewardship Choices for the Watershed Manager <ul><li>Is my community ready to undertake restoration? </li></ul><ul><li>Which mix of stewardship programs is best? </li></ul><ul><li>Who are the best targets for watershed education? </li></ul><ul><li>How am I going to pay for a stewardship program? </li></ul>
    75. 83. Summary This presentation provides a simple introduction to the eight basic watershed protection tools essential to the protection, preservation, and restoration of our lakes, streams, and estuaries. For more information on the watershed protection tools, please consult the Rapid Watershed Planning Handbook , 1998.
    76. 84. Are You an Expert on the Eight Tools of Watershed Protection? <ul><li>Simply use your mouse to click on the correct answer for each multiple choice question. If you are correct, you will immediately advance to the next slide. Good luck! </li></ul>
    77. 85. <ul><li>Land use planning </li></ul><ul><li>County codes and ordinances </li></ul><ul><li>Gravel </li></ul>What is the single most important tool of watershed protection?
    78. 86. At what scale is watershed planning most effective? Largest scale possible Subwatershed scale Stream level
    79. 87. What is the disadvantage of using large lot zoning as a land use planning tool? Large lots spread out development, resulting in sprawl Large lots are often economically unfeasible Large lots mean longer driveways
    80. 88. What is an aquatic buffer? An area of trees that blocks noise pollution Tool designed to polish rough, polluted areas Area adjacent to a shoreline, wetland or stream where development is restricted or prohibited
    81. 89. What is cluster development? Development that groups economically similar groups together Development that reduces individual lot size and creates more open space Development designed to concentrate pollutants in one small area
    82. 90. What is the most destructive stage of the development cycle? Clearing & grading Installation of underground pipes & lines Structure erection
    83. 91. What is the most effective technique for providing erosion and sediment control? Wetting down building sites Increasing cleared areas Minimizing clearing
    84. 92. What is NOT a structural stormwater practice? Ponds Wetlands Infiltration Filtering Systems Buffer clearing Open channels
    85. 93. What non-stormwater discharge is not regulated by the NPDES? Factory discharge Septic systems Farm discharge
    86. 94. What is the primary goal of watershed stewardship programs? Increase public awareness & participation Save money Preserve non-profit status
    87. 95. What is a conservation easement? A practice used to apply and enforce restrictions to preserve natural resources An amendment relaxing conservation restrictions A special dispensation to deputize conservation officers
    88. 96. What are stormwater hotspots? Urban areas that contribute 5-10 times higher pollutant levels in stormwater runoff Areas of increased water temperature that destroy habitat Areas that are 5-10 times more likely to experience flooding
    89. 97. Congratulations! You’re familiar with the eight tools of watershed protection! Contact the Center for Watershed Protection if you’re interested in learning more.
    90. 98. Sorry, try again. BACK
    91. 99. Eight Tools of Watershed Protection Vocabulary
    92. 100. Aquatic corridor <ul><li>Areas of land and water that are important to the integrity and quality of a stream, river, or other body of water. An aquatic corridor usually consists of the actual stream or river, the aquatic buffer, and other areas which are part of the stream’s right-of-way. </li></ul>BACK
    93. 101. Buffer <ul><li>An area adjacent to a shoreline, wetland or stream where development is restricted or prohibited. </li></ul>BACK
    94. 102. Cluster or Open Space Development <ul><li>The use of designs which incorporate open space into a development site; these areas can be used for either passive or active recreational activity or preserved as naturally vegetated land. </li></ul>BACK
    95. 103. Conservation easements <ul><li>A practice used to apply and enforce restrictions to preserve natural resources. Typically, a landowner will grant a parcel of land to a qualified recipient (e.g. public agency or non profit land conservancy organization). The easement gives the recipient the right to enforce the restrictions. The recipient does not assume ownership but does assume long-term responsibility for enforcement and stewardship of the easement. </li></ul>BACK
    96. 104. Floodplain <ul><li>Areas adjacent to a stream or river that are subjected to flooding or inundation during severe storm events (often called a 100 year floodplain, it would include the area or flooding that occurs, on average, once every 100 years). </li></ul>BACK
    97. 105. Illicit connections <ul><li>Illegal and/or improper waste discharges into storm drainage systems and receiving waters. </li></ul>BACK
    98. 106. Impacted stream or subwatershed <ul><li>Stream classification for a subwatershed with 11 to 25% ultimate impervious cover. Urbanization is expected to lead to permanent degradation to stream quality. </li></ul>BACK
    99. 107. Impervious cover <ul><li>Any surface in the urban landscape that cannot effectively absorb or infiltrate rainfall. </li></ul>BACK
    100. 108. Imperviousness <ul><li>The percentage of impervious cover within a development site or watershed. </li></ul>BACK
    101. 109. National Pollutant Discharge Elimination System (NPDES) <ul><li>Established by Section 402 of the Clean Water Act, this federally mandated system is used for regulating point source and stormwater discharge. </li></ul>BACK
    102. 110. Non-stormwater flows <ul><li>Runoff from sources other than rainwater. </li></ul>BACK
    103. 111. Non-supporting stream or subwatershed <ul><li>Stream classification for a subwatershed with more than 25% total impervious cover. These streams are not candidates for restoration. </li></ul>BACK
    104. 112. Open Space <ul><li>A portion of a development site that is permanently set aside for public or private use and will not be developed with homes. The space may be used for passive or active recreation, or may be reserved to protect or buffer natural areas. </li></ul>BACK
    105. 113. Rooftop runoff <ul><li>Rainwater that falls on rooftops, does not infiltrate into soil, and runs off the land. </li></ul>BACK
    106. 114. Sensitive stream or subwatershed <ul><li>Stream classification for a subwatershed with less than 10% impervious cover that is still capable of supporting stable channels and good to excellent biodiversity. </li></ul>BACK
    107. 115. Stormwater “hotspots” <ul><li>Land-uses or activities that generate highly contaminated runoff. Examples include fueling stations and airport deicing facilities. </li></ul>BACK
    108. 116. Stormwater management practice (BMP) <ul><li>A structural or non-structural technique designed to temporarily store or treat stormwater runoff in order to mitigate flooding, reduce pollution, and provide other amenities. </li></ul>BACK
    109. 117. Stormwater runoff <ul><li>Rainwater that does not infiltrate into the soil and runs off the land. </li></ul>BACK
    110. 118. Subwatershed <ul><li>A smaller geographic section of a larger watershed unit with a drainage area between 2 to 15 square miles and whose boundaries include all the land area draining to a point where two second order streams combine to form a third order stream. </li></ul>BACK
    111. 119. Transferable Development Rights (TDRs) <ul><li>A form of incentive for developers in which the developer purchases the rights to an undeveloped piece of property in exchange for the right to increase the number of dwelling units on another site. Often used to concentrate development density in certain land areas. </li></ul>BACK
    112. 120. Watershed <ul><li>All the land which contributes runoff to a particular point along a waterway. </li></ul>BACK
    113. 121. Zoning <ul><li>A set of regulations and requirements that govern the use, placement, spacing and size of buildings and lots within a specific area or in a common class (zone). </li></ul>BACK

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