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... Storm Water Master Plan .... September 1996 ...
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Arlington County, Virginia Department of Public Works ... Public Works Planning Division ARLINGTON COUNTY, vm.GINIA
Arlington County Board
James B. Hunter, ill, Chair Ellen M. Bozman, Vice Chair Albert C. Eisenberg ... Paul Ferguson Christopher Zimmerman
Arlington County Commissions
Planning Commission, Elinor Schwartz, Chair ... Environment and Energy Conservation Commission, R.B. Neustadt, Chair
Office of the County Manager Anton S. Gardner, County Manager ... William T. Donahue, Deputy County Manager
Prepared By
William H. Frost, P.E., Senior Planner Department of Public Works Public Works Planning Division
Storm Water Master Plan Team ....
Greg ZeIl, Department of Parks, Recreation, and Community Resources Rachael Slemons, (formerly with Department of Management and Finance) Bill Roberts, Department of Community Planning, Housing, and Development Carol McCoskrie, Office of the County Attorney Jeff Ham, Department of Environmental Services ... Mark Graham, (formerly with Department of Environmental Services)
Other Assistance
Many reviewers from the following departments, whose contributions are gratefully acknowledged.
Department of Public Works Department of Parks, Recreation, and Community Resources Department of Community Planning, Housing, and Development Department of Environmental Services
... CONTENTS
CHAPI'ER. ONE: INTRODUCTION . . . • o...... 1 ORGANIZATION OF THIS MASTER PLAN . . . • ...... • . • • ...... 1 KEY CONCEPTS IN STORM WATER MANAGEMENT ...... ••...... 2 COMPREHENSIVE PLANNING CONTEXT ...... •...... • 3 mSTORY OF STORM WATER FACILITY PLANNING IN ARLINGTON. .. 4
CHAPTER TWO: POLICIES, PRINCIPLES, GOALS, AND OBJECTIVES •...... 6 SUMMARY OF EXISTING POUCIES ...... 0...... 6 PROPOSED POUCIES • ...... • ...... • . . .. 7 GOALS AND OBJECTIVES ...... • ...... • ...... 7 Reduce or control damages from flooding ...... •...... 7 Improve runoff quality •...••...... •.....•...... 8 Preserve and improve stream valleys ...... •...... 8 Preserve groundwater resources ...... 9 PRINCIPLES .....•...... 9 Coordination principles . . . . • ...... • ...... 9 Planning and design principles ...... 10 Financing principles ...... • . . . . . • o. . . . . 10 Maintenance principles ...... 11
CHAPI'ER. THREE: REGVLATORY REQUIREMENTS ...... 12 FEDERAL AND STATE LAWS AND REGULATIONS ...... 12 Federal Regulations and Programs . . . . • ...... 12 State Laws and Regulations ...... •..... 12 ARL~GTONORDINANCES ...... 13 SIGNIFICANT STATE AND FEDERAL REGULATIONS ...... 15
CHAPTER FOUR: WATERSHED EVALUATION ...... 17 WATERSHED DELINEATION ...... 17 CHANNEL CHARACTERISTICS ...... •...... 17 WATERSHED CHARACTERISTICS ...... ••...... 20 l..a.nd Use. . • ...... • • . • . • . • • • . . . • . • ...... 20 Imperviousness ...... 21 Forests ...... 24 Wetlands ...... 28 WATER QUALITY PROBLEMS . '...... 28
o Background ...... · ...... 28 Arlington Stream Quality ...... 30 Chesapeake Bay Quality ...... 32 FLOODING PROBLEMS ...... 32 WATERSHED PRIORITY RANKINGS ...... 33 Classification ...... 33 Priorities for stream restoration ...... 35 Priorities for water quality improvements ...... • . . . 36 Priorities for flood damage reduction ...... 36
\ \. ,.. CHAPTER FIVE: EXISTING AND PROPOSED PROGRAMS ...... 37 I NEW DEVELOPMENT AND REDEVELOPMENT ...... 38 CONSTR..UCTION . . • ...... • • • . . • • • • . • • . . . . . • • • 40 EXISTIN"G DEVELOPMENT' ...... • • • . . . • • • • . . . • . • • . . . 41 r-' POLLUTION PREVENTION - ILLICIT DISCHARGES AND SPILLS ...... 42 I POLLUTION PREVENTION - PUBLIC EDUCATION AND OUTREACH' ... 43 ROADS, HIGHWAYS, AND BRIDGES .....•...... 45 STREAMBANKS, WETLANDS, AND FLOODPLAINS ...... 45 MONITORIN"G ...... • . • ...... • ...... • . . . . 46
CHAPTER SIX: CONCLUSIONS AND RECOMMENDATIONS ...... • • ...... 48 SYSTEM KNOWLEDGE ...... • . . . . • • ...... 49 EXISTING DEVELOPMENT' ...•...... ••...... 51 NEW DEVELOPMENT ...... •....••...... •. ~ ... 51
BIBLIOGRAPHY ...... •...... 52 Comprehensive Plan History ...... 52 Storm Sewer Plan History ...... •.•...... 52 r-'
Policies, Principles, Goals, Objectives, Standards ...... 52 I Watershed Delineation ...... • ...... 54
ABBREVIATIONS ...... 56 APPENDIX A: FEDERAL AND STATE LAWS AND REGULATIONS ...... 58 r APPENDIX B: STORM DRAINAGE CAPITAL IMPROVEMENTS ...... 65
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rI ~ FIGURES
Figure 1: Original and Remaining Streams ...••.•...... 18 Figure 2: Watersheds in Arlington County and Vicinity .•...... •.... 19 Figure 3: Existing I.Jlnd Use. . . . • ...... • ...... 22 Figure 4: Impervious Surface ...... •...... 25 Figure 5: Forest Cover ...... •.....•...... •...•...... 27 Figure .6: Potential Wetlands ...... 29
.~ TABLES
Table 1: Comprehensive Plan Elements ..•...•..•.••...... •...... 3 Table 2: Proportion of Land Use in Each Watershed ...•.•...... 23 Table 3: Watershed Characteristics •...... •...... 26 Table 4: Stonn Water Pollutants and Sources ...... •. . . . 31 Table 5: Watershed Evaluation ...... •...... 34
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~ I PREFACE
It has been fifty years since a comprehensive study of drainage needs has been made for Arlington County. In those five decades the technology and purpose of storm water management systems have changed substantially. Environmental regulations have added new constraints and opportunities. There is an increasing importance on designing storm drainage systems to improve runoff quality as well as control flooding. Emphasis on enhancing and restoring natural stream valleys has brought changes in the focus of storm drainage. Technology and design methods are changing rapidly, as assumptions about current engineering practices are challenged by new research.
This Storm Water Master Plan has been driven by these changes. It is being written as a forum to discuss Arlington County's policies and goals for storm water management, and to reach a consensus among citizens and County agencies on programs and projects to correct runoff problems.
The guiding philosophy behind the Storm Water Master Plan is that storm water management problems cannot be solved piecemeal, either site-by-site or agency-by-agency. Runoff does not respect jurisdiction boundaries or property lines, and analysis of problems must take a watershed approach. To develop technically sound projects that are supported by the community; a diverse group of specialists and interest groups are needed to contribute to planning and design.
No Master Plan can guarantee a particular result. Circumstances and priorities change and the plan must be flexible enough to accommodate change. In the field of storm water management, changes have been rapid. New laws and regulations have revised many of the assumptions under which a plan would have been developed earlier. There is no reason to expect these changes to stop. An important purpose of this plan is to provide the policies and principles that can guide revisions to specific watershed projects as changes occur.
The activities proposed as a result of this planning effort are somewhat unconventional. Instead of projects to be designed and built through the Capital Improvement Program (CIP), several programs are proposed to meet plan objectives. A series of proposed studies will guide project planning and may lead to future CIP projects.
Steps required to develop CIP projects include (1) establishing priorities for programs and watershed studies (done as part of this Master Plan), (2) carrying out data collection and analysis with the programs discussed in Chapters 5 and 6 to identify deficiencies, (3) developing sources of funding and preliminary concepts for improvement projects, and (4) developing a detailed design. Projects requiring County capital funds are programmed in the six-year Capital Improvement Program (CIP). County Board reviews of the CIP and the annual budget are opportunities for public review of proposed storm water projects, priorities, and funding. Where new development changes runoff characteristics substantially, review of storm water management is part of the County staff review of development plans. In addition to these review opportunities, Arlington County is committed to a thorough and open public participation process in the consideration of any new County facilities. As circumstances change, the plan should represent the most current thinking of the County. Between comprehensive plan updates, amendments are appropriate. Should the goals and objectives change, should new regulations be adopted, should specific facility proposals need to be changed, then this plan should be amended. Proposed amendments should be considered by other County commissions as appropriate, and be subject to an open public participation process developed for the type of amendment.
The Stonn Water Master Plan has been developed through a process of inter-agency and citizen participation. The Department of Public Works has had primary responsibility for its development, with input from a Storm Water Master Plan Project Team consisting of representatives from the following departments:
Department of Environmental Services Department of Parks, Recreation, and Community Resources Department of Com~unity Planning, Housing, and Development Department of Management and Finance County Attorney's Office
Many references were used to develop the Master Plan. Liberal use was made of these works, both paraphrased and quoted directly, though no formal method of quotation and footnoting has been used. A Bibliography listing all source materials is included.
r- I CHAPrER ONE:· INTRODUCTION
ORGANIZATION OF THIS MASTER PLAN
The primary purpose of any master plan is to take a comprehensive look at existing conditions, forecast changes, and propose improvements. The master planning process is a systematic approach to planning facilities and programs. . It proceeds from agreeing on policies, to setting goals and objectives, to recommending facilities and programs which can be accomplished within the resources available. Following adoption of a master plan, a capital improvement program may be established, or ordinances and management programs may be implemented. At this point, plans and designs for infrastructure or land development may proceed according to standards and criteria that follow from the master plan objectives.
The Master Plan includes the following chapters:
INTRODUCTION gives an overview and background for the Master Plan, with discussion of storm water management concepts and comprehensive planning. It also includes background on the planning and construction of the storm water management system as it now exists.
POLICIES, PRINCIPLES, GOALS AND OBJECTIVES gives the County policy on storm water management and the overall agreement 'on general goals and procedures. This chapter also discusses the overall philosophy of the County's storm water management program. For the underlined elements below, a discussion is provided on the existing situation and recommendations are made for proposed changes.
Policies apply to all projects and situations and generally have been approved by action of the County Board. Principles are the guidelines and assumptions describing how the work of the plan should be carried out. Goals describe the purpose of storm water management in Arlington; they are a strategic set of ends toward which the plan is directed. Objectives are specific, measurable targets which when achieved, will advance the program toward one of the goals and can be used to determine to what degree the goals are being satisfied.
REGULATORY REQUIREMENTS summarizes the Federal and State laws which govern how the County can plan and design facilities or which programs it is required to undertake. (In some cases, laws 8.lso prevent the County from undertaking some actions). Applicable sections of County ordinances which guide citizens and developers in what they are allowed to do are also summarized. .
WATERSHED BV ALUATION identifies Arlington's drainage areas and subwatersheds and classifies them by watershed and channel characteristics. A discussion of known runoff pollution and flooding problems is also presented. Watersheds are ranked in priori.ty for more detailed analysis based on this earlier evaluation
1 EXISTING AND PROPOSED PROGRAMS reviews the actions now underway and those that need to be taken to improve Arlington's streams and watersheds. They include studies to be made, pollution prevention activities, and further steps in planning and analysis.
CONCLUSION AND RECOMMENDATIONS summarizes the findings and recommends further activities to be undertaken based on the priorities established.
KEY CONCEPTS IN STORM WATER MANAGEMENT
Storm water runoff occurs when rain falls on an impervious surface or falls fast enough to exceed the infiltration capacity of the soil. In undeveloped areas it collects in swales, gullies, and streams, flowing to major waterways.
In urban areas, the overall storm water system includes:
Overland flow. This is the earliest stage of runoff over lawns, forest, streets, parking lots, rooftops, and all other surface features. This flow is sometimes called sheet flow, because it is not concentrated into gutters.
Storm sewer system (or minor system>. This collection system of inlets, pipes, manholes, and channels has been designed and built to replace the natural drainage features lost during development. It has been termed the minor system because it is designed to convey the runoff from smaller, frequently-occurring storms. In Arlington, the 10-year storm has been designated the cut-off point. A storm of this magnitude is one that has a 10% probability of occurring in anyone year. The term does not refer to the length of tim~ between storm occurrences.
Overland relief system (or major system). These are easements or facilities which convey runoff from large, infrequent storms. It consists of whatever paths are available -- planned or unplanned -- for flood waters to flow to a receiving stream. It may include streets, easements, swales, and ditches, as well as recognized floodplains. The major system will function regardless of whether it has been designed. If a route has not been provided by site engineers, flood waters will flow downhill on their own, perhaps through yards, homes, and businesses.
Facilities built to carry overland relief are usually designed for the l00-year storm (1 % probability in anyone year) and include culverts to carry streams under roads and larger downstream pipes or box culverts.
In the past, the storm water design philosophy was to collect as much runoff as possible and move it as rapidly as possible downstream. This created new problems in the receiving streams, including high peak flows, excessive erosion and sedimentation, and increased pollution and decreased value as wildlife habitat.
2 Recognition of these problems in the last 20 years has caused storm sewer design to evolve into storm water management. Design practices have changed. Storm water detention is now a common practice, recognizing that upstream storage can reduce the need for and size of storm sewers. Emphasis on protection of natural streams has led to erosion and sediment control ordinances and further limits on peak flows from development sites. The water quality impacts of runoff, while still poorly. understood, have driven changes in design. Finally, the importance of land use management, including minimizing impervious cover, clustering development, and creating buffers around streams, are an important part of site design.
Arlington County has engaged in comprehensive planning for nearly 40 years. The principal guide for the future of the County is its comprehensive plan. Although a number of the elements of the comprehensive plan were prepared beginning in the 1930s and 1940s, they were not brought together and adopted as the County's comprehensive plan until the 1950s.
County staff and citizens began work on a comprehensive plan in late 1955, and the County Board approved the program in January, 1956. At the 1958 session of the General Assembly, the procedure for adopting the Master Plan was revised so that the Planning Commission would approve an element and it would be adopted by the Board. All of the elements of the County's comprehensive plan were adopted after that change. . . There are eight separate elements of the comprehensive plan. Two relate to the pattern of development and six are plans for the infrastructure to support land use activities. Table 1 shows the dates of adoption and most recent update for each element. Titles given are those of the most recent update.
Table 1: Comprehensive Plan Elements
Date Comprehensive Plan Element Adopted
General Land Use Plan 1961 Chesapeake Bay Preservation Ordinance 1992 Water Distribution System Master Plan 1958 Storm Water Master Plan 1958 Master Transportation Plan 1960 Open Space Master Plan 1994 Sanitary Sewer System Master Plan 1961 Recycling Program Implementation Plan 1990
3 The General Land Use Plan (GLUP) designates the location and type of land use activities that are to occur within the County. The Chesapeake Bay Preservation Ordinance is an overlay to the Zoning Ordinance limiting certain types of land use activities in Chesapeake Bay Preservation Areas. ... ,. The Master Transportation Plan describes long-range goals and projects for improving transportation facilities. Similarly, the Water Distribution System Master Plan, the Sanitary Sewer System Master Plan, and this Storm Water Master Plan describe the long-range goals and projects to provide infrastructure to support planned land use activities. The Open Space Master Plan forecasts the need for open space, including recreation and park areas. Finally, ,... I the Recycling Program Implementation Plan describes programs and projects for recycling solid waste.
HISTORY OF STORM WATER FACILITY PLANNING IN ARLINGTON
Until the 1940s, no comprehensive study of Arlington's storm drainage had ever been done, nor had one been needed. Arlington County was largely farmland until the tum of the century. Even as late as 1920, the County's population was only 16,000, at which time the County consisted of farms and suburban villages connected by interurban and steam nrllroads and a few roads. About that time more intensive development began. From 1930 to 1950 Arlington was the fastest growing County in the United States.
The County's water and sewer utilities were established at the beginning of this period of growth. The water distribution system began operation in 1927 and the first comprehensive system of sanitary sewers began in the mid-1930s. Unlike water and sewer services, storm drainage could rely on nature while land development intensified. As a result, the original stream network still carried most of the runoff. World War II changed Arlington's character completely. Roads were built, garden apartments were developed, farms were subdivided, and Arlington rapidly became a bedroom suburb. In 1942, the County commissioned Chester Engineers to study storm sewer needs. The resulting report was the basis for a series of bond issues which enabled a program of storm sewer construction to begin.
Throughout the 1940s and 1950s as development continued, drainage problems manifested themselves. Annual reports at the time show pictures of heavily eroded gullies and swales where the problems were eliminated by building storm sewers and putting the flow underground. It was in this period that Arlington's storm sewers grew into a large interconnected system and many of the streams were lost.
The County's first, and to date only, master plan for storm water was submitted to the Planning Commission in December, 1957. The Commission reviewed the Chester Report at its meeting on December 2, 1957, where there was discussion of some current drainage projects and the relation of runoff to land use changes and some recent development sites. The Commission concluded by requesting a three- or four-page supplement be written to make the 1943 study current and to explain the storm sewer plan. The supplement and the . Chester Report together became the Storm Sewer Master Plan.
4 The plan was sent to the County Manager on December 13th, 1957. It described drainage improvement measures that could be taken beyond the program of storm sewer construction outlined in the Chester Report. Recognizing that runoff is generated by impervious surfaces, the plan discussed limiting changes in land use· and development to keep runoff at the levels forecast in the Chester Report. Floodplain land acquisition was recommended, as a more economical method of avoiding flooding than enclosing major streams. This was carried out; the land now forms parts of parks adjacent to Lubber Run, Four Mile Run, Gulf Branch, Donaldson Run, and Windy Run.
Stream improvements in the floodplains were recommended to improve flow capacity. These included creating flat side slopes on either side of the channel, to be sodded against erosion. Maintenance, including removing sediment deposits, was considered essential.
The Planning Commission reviewed the Master Plan for Storm Water Sewers at its meeting on March 24, 1958, adopted it as a portion of the Master Plan for Arlington County, and passed it on to the County Board with a recommendation for approval. The County Board considered the plan at its meeting on March 29, 1958 and unanimously deferred action until June 7. At that meeting, the plan was approved as an element of the County Comprehensive Plan.
No further County-wide review of storm drainage needs was done in the years between the adoption of the Master Plan in 1958 and 1974. Projects were designed and built based on identification in the 1958 plan, with their primary purpose to increase the capacity of the system.
Scattered-site storm water planning was done by developers subdividing land and building storm sewer systems to serve the new streets and buildings. County storm water planning occurred during the process of adopting new ordinances, frequently as a result of mandates from Federal or State authorities. The ordinances, in particular, became a de facto storm water plan, and helped guide· design and construction of new development to avoid severe runoff impacts. The first of these was Federal legislation (PL 93-271) in 1974, which required local government agreement to manage storm water flows as a condition to making channel improvements to Four Mile Run. They will be discussed in a later section on Regulatory Requirements.
5 CHAPrER TWO: POLICIES, PRINCIPLES, GOALS, AND OBJECTIVES
SUMMARY OF EXISTING POLICIES
The storm water policy 'described in this section comes from several documents , most of which have been approved by action of the County Board, including:
Ordinances for floodplain management, storm water detention, and preservation of the Chesapeake Bay, and
Environmental assessment procedures.
The first policy describes the purpose of storm water management, and the second sets a policy for the process of planning, designing, and building storm water projects. The first applies to all projects in every situation, the second to public projects only.
1. Management of Arlington County's stom water is necessary and shall be conducted to preserve and promote the general health, welfare, safety, and economic well-being of the Arlington County community:
la. To regulate the development of flood-prone areas, protecting public utilities 'and the natural drainage and preventing the inadequate design and construction of development in areas subject to flooding. (Fl~plain Management Ordinance)
lb. To reduce the harmful effects of storm water runoff on streams, park lands, ~ private properties and other areas in Arlington County. (Stormwater Detention " } Ordinance)
lc. To protect and restore natural watercourses to a condition or quality that will permit public use and will support the propagation and growth of aquatic life which might reasonably be expected to inhabit them. (Chesapeake Bay PreseIVation Ordinance)
2. When a project is identified as having potentially significant eJiviron~ental impact, the impacts are to be carefully and thoroughly considered as part of the overall project evaluation according to the standards of Administrative Regulation 4~4. Project teams for such projects should include members from a range of departments and disciplines, including landscape architects, natural resource specialists, environmental engineers, planners, and civil engineers as applicable.
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6 ~ ,. - PROPOSED POLICIES
The first proposed policy is written to ensure that County agencies conform with drainage ~ policies and ordinances for all construction projects. The second is a policy of adequate drainage that is implicit in the County's storm water management policy but is not spelled out by ordinance. Opportunities for incorporating adequate drainage policies and standards .... by ordinance in a revised storm water ordinance are discussed in the section on Existing and Proposed Programs.
3. Facilities built by public agencies (including Arlington County departments, the Virginia Department of Transportation (VDOT), and the Arlington School Board) must meet or exceed applicable Federal and State drainage laws and Arlington County ordinances.
4. Adequate drainage should be provided for surface waters and the discharge of such waters into natural watercourses without adverse impact on the land or watercourses affected.
GOALS AND OBJECTIVES
The County's Storm Water Master Plan is adopted to strive toward the following goals and objectives. Goals are listed in order of priority, while objectives are more specific targets in no particular order.
Reduce or control damages from flooding
Reduce the exposure of people and property to flood hazards.
Eliminate flooding or damage to houses, buildings, or property from overland relief
Whenever possible, for flood plain alterations, preserve the hydraulic and flood carrying capacity within the altered or relocated portion of the natural channel, the storage characteristics of flood plains, and the character of the natural environment.
For designated major drainageways, consisting of a floodway and a flood fringe or storage area, preserve capacity by floodplain regulations preventing channel encroachment.
Avoid filling of flood fringe areas, and where possible, reestablish major drainageways where they have been obliterated by development.
Develop a program for collecting and analyzing storm flow and rainfall data to establish rainfall/runoff relationships useful for calibrating computer models.
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7 Develop a program to collect data on flood occurrences and damages in a systematic and uniform manner.
Develop a program to update Federal Emergency Management Agency (FEMA) floodplain maps with information from suitably calibrated computerized runoff and flow models, ae<;ording to a list of priorities for watersheds and land uses.
Reduce flooding on streets to meet approved drainage criteria.
Improve runoff quality
Eliminate violations of any State or Federally mandated water quality criteria from Arlington storm sewer outfalls.
Eliminate any impairment of designated beneficial uses of all Arlington streams (fishable, swimmable waters) which occurs from runoff pollution.
Eliminate illicit discharges in dry weather flows.
Reduce trash and litter deposits from the storm sewer outfalls into streams.
Reduce existing levels of pollutants from runoff, including nutrients, toxic substances, thermal pollution (heating), and excessive sediment.
Develop a continuing monitoring program for stonD sewer outfalls and streams to characterize runoff and assess improvements.
Emphasize public education on runoff pollution and techniques for reducing it.
~ Preserve and improve stream valleys I
Minimize erosion of stream beds and banks. Minimize soil erosion in the watershed and resulting sedimentation problems.
Restore degraded stream ecosystems and expand habitat for desirable species, particularly native plant and animal populations.
Improve the biotic diversity of the stream environments.
Inventory stream water and habitat quality and develop programs to improve the streams based on the results.
Retain non-urbanized floodplains in a condition that minimizes· interference with flood water conveyance, flood water storage, aquatic and terrestrial ecosystems, and the ground/surface water interface. . ~
8 ~ Preserve groundwater resources
Maintain adequate infiltration to assure base flows in streams and recharge of groundwater.
Minimize pollution of groundwater from infiltration.
PRINCIPLES
The following principles will be used as ge~eral guidelines and assumptions for carrying out the work of the Storm Water Master Plan.
Coordination principles
Storm water runoff is a regional problem that does not respect the boundaries between jurisdictions, between public and private properties, or between established areas and new development. Watershed boundaries link everyone who lives in, works in, or passes through Arlington to their neighbors.
A regional or watershed approach to storm water detention, runoff quality improvements, or other drainage projects is preferable to numerous small, marginally effective detention systems, ponds, or other Best Management Practices (BMPs). These should be used only when required to preserve adequate downstream capacity. pIII' .. Storm water runoff is a part of the total urban environmental system. Planning for storm water systems crosses functional boundaries, linking plans for land use, open space, and transportation. As a consequence, a master plan for storm water must be compatible with other plans.
Storm water management is an activity which crosses boundaries between County agencies. Plans and programs must be developed with close cooperation between agencies responsible for open space (DPRCR), stream valleys (DPRCRlDPW), storm water quality (DES), storm drainage facilities (DPW), County facilities management (OSS and Schools), hazardous materials spills (Fire) and land use planning (DCPHD), at a minimum.
The Master Plan must also provide for integration of storm water management programs with ordinances for erosion and sediment control, storm water detention, Chesapeake Bay preservation, site plan review, flood insuranCe, floodplain management, and other land development related programs and laws.
Because the surrounding community is the source of the stress placed on Arlington's streams, strong efforts should be made to involve the community in reducing the amount of runoff and pollution entering the streams, and in participating in their cleanup, restoration, and monitoring.
9 Planning and design principles
There is no single method of handling storm water that is appropriate for every development site or every drainage problem. A combination of conveyance improvements, storage facilities, groundwater recharge, purchase of flOodplain easements, stream valley improvements, and source controls provided by both the County and private landowners is needed to ensure storm water management enhances the quality of life in Arlington rather than detracts from it.
Project planning and programming are to consider a broad range of alternatives, and all reasonable alternatives are to be carefully evaluated.
P1 Major projects are to be planned and designed in a manner which allows for the public I I participation and environmental assessment throughout each successive phase.
Planning and design of storm water drainage systems should not merely transfer problems from one location to another. Modifications which create problems downstream or divert runoff across a drainage divide should be avoided.
Master Plans for stream or storm sewer improvements are to be prepared for a watershed or subwatershed as a whole. They should take into account both the minor system, to assure a ~ 1'1 minimum of drainage complaints., and ~e major system, to limit damages from flooding.
The storm water management system should be designed to use the features or duplicate the functions of the natural drainage system to provide infiltration, control the velocity of runoff, filter pollutants, or recycle nutrients.
Natural drainage ways should be used for storm runoff waterways wherever possible. Major consideration should be given to the flood plains an~ open space requirements of the area.
Natural watercourses (both perennial and dry ditches) should not be filled or straightened significantly, as such actions tend to reduce storage and increase the velocity downstream.
Flood peaks should be reduced and erosion controlled so the natural channel regime is preserved as much as possible. 'J=*l Fmancing principles
Financing of storm water improvements should be based on the principle that costs be borne by those contributing significantly to the problems addressed by improvements. Where existing development caused problems, costs should be borne County-wide by existing residents and businesses through funding in the portion of the County's Capital Improvement Program financed with General Fund pay-as-you-go or bond dollars. Where new development is projected to cause problems, it should contribute to the cost of improvements.
10 Where regional facilities are built or planned which have the capacity to detain increased flows, new development should pay a pro-rata. share for construction and maintenance of such facilities.
New development should pay for and construct on-site improvements necessary to provide the development with adequate storm water -management facilities and ensure adequate capacity is preserved immediately downstream.
When storm drainage improvements to reduce flooding are projected to cost more than the property being protected, consideration should be given to acquiring the property in lieu of constructing otherwise unnecessary facilities.
., General fund and capital improvement financing for storm drainage programs and projects will be allocated in competition with other County priorities, and as funding is available.
Maintenance principles
Both publicly-owned and privately-owned storm sewers and storm water management systems should receive regular maintenance.
Where detention or water quality BMPs require regular or periodic maintenance, such maintenance should be ensured by the County through a maintenance agreement with the owner or developer or ·some other mechanism that a~hieves an equivalent objective.
Inspection of privately-owned detention systems, inlets, junctions, and pipes shall be undertaken at regular intervals to insure facilities upstream of County storm sewers and outfalls are in good working condition and not contributing pollutants to the _County-owned system.
~ County-owned storm sewer inlets, junctions, and pipes should be inspected regularly. Catch basins and inlets should be cleaned out at regularly scheduled intervals.
Rehabilitation and replacement project priorities should be established and weighed against the need for new facilities. Annual investments should be made in replacement or .. rehabilitation of structurally unsound or very old storm sewer facilities .
11 CHAPTER THREE: REGULATORY REQUIREMENTS
FEDERAL AND STATE LAWS AND REGULATIONS
Federal Regulations and Programs
A number of storm water programs have been created by legislation. Please refer to the detailed discussion of these in Appendix A for clarification of the following brief listing.
Four Mile Run Watershed Management Planning Program Floodplain Insurance Wetlands NPDES (Storm Water Program) Coastal Zone Dams, Dikes, and Structures in Navigable Waters
State Laws and Regulations
Specific authority granted to local governments and required by statute:
Erosion and Sediment Control Chesapeake Bay Preservation ,~ Specific authority granted to local governments but not required by statute: I
Adequate Drainage Health, Safety, and Welfare Stormwater Utility Fund Flood Damage Reduction Act Stormwater Manag~ment Comprehensive Flood Control Program Wetlands Zoning Ordinance and Wetlands Boards
Authority reserved to the Commonwealth
Dam Safety Act Ownership and Uses of Submerged Lands Control by Commonwealth as to Water Quality Public Policy Regarding Waste Discharge Water Quality Standards Permit Authority Virginia Water Protection Permits Industrial Discharges
12 ARLINGTON ORDINANCES
Arlington County has five ordinances which regulate how citizens and developers deal with storm water, runoff, and streams. All but one have been enacted to comply with programs or mandates from the Federal or State governments. A short description of each follows.
Chapter 26: Utilities
Date Adopted: October 11, 1969
The Utilities Ordinance codifies the County's powers for protecting the health, safety, and welfare of its citizens regarding pollution of streams and storm water.
Section 26-4 of the Utilities Ordinance deals with the storm sewer and drainage system. Section 26-4(a) prohibits anyone from opening or interfering with any storm drain structure or making any connections with or openings into any part of the storm drainage system. Part 26-4(b) prohibits disposal of any material capable of causing a stoppage or disrupting the flow of storm water or adversely affecting the hydraulic capacity of the watercourse or drainage structure. 26-4(c) prohibits discharges into any storm drain or open stream of sewage, chemicals, oils, tars, or other wastes or substances likely to have an adverse effect on storm drains or watercourses, or to endanger life or limb, or which may constitute a public nuisance.
Chapter 48: Floodplain Management
Date Adopted: September 24, 1977
The floodplain management regulations in this Chapter have been adopted to bring the County into compliance with the National Flood Insurance Program and allow Arlington ~-, citizens to have the benefits of flood insurance. They date from the same year the State provided authority by first passing the Flood Damage Reduction Act.
~ The Ordinance meets the requirements of the NFIP regulations by doing the following:
Defining and establishing the floodplain district, including all those areas subject to the one hundred-year flood.
Describing the uses which are permitted and banned in the floodplain district.
Setting out flood damage control and floodproofmg requirements for new construction in the floodplain district.
Defining the information needed for a building permit and development plan for construction in the floodplain district.
13 Providing for administration and enforcement measures.
Chapter 57: Erosion and Sediment Control ( E & SC)
Date Adopted: June 27, 1976
The County's E & SC Ordinance followed the original authorizing legislation by three years, but predated the program mandated in the 1980s. It is subject to annual audit by the State and is now in compliance with the State program.
Persons engaging in land-disturbing activities must submit an erosion and sediment control plan and have it approved by the County before beginning work. Both applicants and County staff are to use the "Virginia Erosion and Sediment Control Handbook" in designing and approving control measures.
Chapter 60: Stormwater Detention
Date Adopted: September 11, 1976
Arlington's Stormwater Detention Ordinance also pre-dates the State's program. It was first enacted in response to the Four Mile Run Watershed Management Program. At that time it applied to that drainage basin alone. The program required the local governments in the watershed to insure there would be no adverse impacts on the capacity of the channel improvements by future development. Arlington's response was to adopt this Ordinance, which imposed a requirement of storm water detention on developers in the Four Mile Run watershed.
The ordinance was extended County-wide in 1982. Since the program does not include water quality controls, the State does not consider it a Storm Water Management program under its current authorizing legislation and regulations, enacted in 1990. Should the Ordinance be changed, it will have to m~t the new regulations.
The Detention Ordinance requires new development to maintain runoff characteristics similar to those of undeveloped land, regardless of the prior land use. Because of its history, there are different regulations for designing detention in the Four Mile Run basin than in the rest of the County. Criteria for requesting a waiver are included, as are administrative and enforcement provisions.
Chapter 61: Chesapeake Bay Preservation
Date Adopted: August 14, 1992
The Chesapeake Bay Preservation Ordinance was adopted as a direct result of a State mandate in the authorizing legislation in 1988. The Ordinance was approved by the Virginia
14 Chesapeake Bay Local Assistance Board, although it did not follow the State regulations and guidance which were not written with a completely developed jurisdiction in mind.
The authorizing legislation requires all local governments in Tidewater Virginia to regulate development in areas which are sensitive to the Chesapeake Bay. Arlington passed the Chesapeake Bay Preservation Ordinance, which creates an overlay of Chesapeake Bay Preservation Areas to the Zoning Map where some land uses are permitted or prohibited. It was adopted as part of the Comprehensive Plan, and a Source Control Plan and Fund were set up to reduce runoff pollution from already developed areas as well as new development sites.
Although the State's regulations require structural runoff quality controls for new development, Arlington's ordinance, which allows participation in the Source Control Plan as a substitute, was approved. In both the regulations and the ordinance, participation in a storm water management plan meeting the "State storm water regulations is also an acceptable alternative to on-site controls.
SIGNIFICANT STATE AND FEDERAL REGULATIONS
There are many ways the laws and regulations interact with" each other across three levels of government. The most basic interaction is an authority or mandate, where a higher level of government either allows, requires, or encourages a lower level to take some action. There are many of these in the field of storm water management. The discussion which follows covers the most significant laws and regulations which affect Arlington County, and what the County's response has been.
The Federal Storm Water NPDES Program requires jurisdictions with a population greater than 100,000 to file with the EPA or the"appropriate State agency for a permit for discharges from storm sewers. The State Water Control Law gives this permit issuing authority to the Virginia Department of Environmental Quality (VDEQ). Arlington filed Part 1 of its permit application in May 1992, and Part 2 in May 1993. By mid-1996, VDEQ had not issued the permit. Once issued, this permit would satisfy the State Chesapeake Bay requirements for a _ storm water quality management program. It would also exempt Arlington from additional water quality measures that might be required under the Federal and Staste Coastal Zone programs.
The State has passed legislation authorizing local governments to adopt ordinances for the following programs:
The Adequate Drainage statute gives Counties the power to provide for adequate drainage, install and maintain drainage systems, and acquire land and buildings to carry out the purpose. None of Arlington's ordinances address this power explicitly.
In some jurisdictions, and in the State's storm water management regulations, developers are required to show there is an adequate outfall for drainage from their sites. If the existing
15 system is inadequate, they are required to limit peak flows or increase downstream capacity at their expense. They are further prohibited from discharging any sheet flow or concentrated runoff onto adjacent properties if it will cause damage.
The Storm Water Utility legislation authorizes establishment of a utility fund or service charges for storm water control programs that meet State storm water management regulations (see below). A utility fund is one mechanism for sharing storm water management costs among new development, existing development, residential, commercial, and tax-exempt properties.
The most significant State legislation is the Storm Water Management Act and regulations, which authorize localities to create a program of storm water quantity and quality management. The regulations are written with on-site structural controls in mind, but other methods are allowed. For example, a storm water management plan using large publicly owned detention facilities to protect downstream channels can meet the regulations without requiring developers to build small on-site systems.
The State's storm water management regulations provide criteria for adequate drainage and detention design, and a State-approved program is a pre-requisite to establishing a storm water utility fund.
16 CIIAPfER FOUR: WATERSHED EVALUATION
This Chapter is designed to review the condition, degree of development, and known problems with Arlington's watersheds, streams, and drainage channels. These factors help determine which of the Plan's goals are appropriate for each watershed. It concludes with a discussion of priorities and a list of which watersheds are the best candidates for further study to meet the goals of flood damage reduction, water quality improvements, and stream restoration.
WATERSHED DELINEATION
Watersheds are usually defined based on the location and size of perennial streams. This is not possible in an area which is completely storm sewered. In these cases, there are several evaluation criteria which can be used to separate or combine a network of tributaries, channels, and storm sewers into watersheds. Among them are channel length, watershed area and channel/pipe size.
Watersheds have been delineated for this plan using the following steps:
I. Using pre-development maps, historically named tributaries were identified. The County's drainage falls generally into three basins, two of which are streams which themselves have named tributaries: Pimmit Run and Four Mile Run. The other basin is direct drainage to the Potomac River. Figure 1 shows the original drainage. Besides the main stems of Four Mile Run and Pimmit Run, five tributaries to Four Mile Run, one tributary to Pimmit Run, and five Potomac tributaries were named on old USGS and County maps.
3. Since stream restoration is a goal of the plan, the remaining open streams were identified and individual watersheds were drawn for them. Four smaller Potomac tributaries and two small Four Mile Run tributaries were added and Little Pimmit Run was subdivided into branches.
4. A map of these subdivided watersheds was compared to the one used in Arlington's previous storm sewer plan. Where useful delineations were made earlier, they were kept. Some of the older areas were combined. The final map is shown in Figure 2. Ignoring the mainstem of Pimmit Run, most of which is outside the County boundary, 33 watersheds cover 33 square miles. with an average area of 642 acres each.
CHANNEL CHARACTERISTICS Watersheds in an urbanized area may have a combination of man-made and natural drainage channels. The degree of channel development in a watershed can be assessed by looking at how the main drainage channel has been modified. A qualitative assessment of the proportion of tributaries in storm sewer can also be made. Using these measures, Arlington's drainage channels have been classified in the following five categories.
17 .~
Figure 1: Original and Remaining Streams
18 . Figure 2: Watersheds in Arlington County and Vicinity
19 The least developed channel system is a natural stream and its tributaries dmining a foreste4 or agricultural basin. Low levels of development may create localjzed areas where storm sewer has been installed with outfalls into the stream, or where culverts have been built to carry the stream under roads or railroads.
A modified drainage network has all its tributaries replaced by storm sewer, but the main channel is still an open stream. In these watersheds, the stream will have been modified to handle higher peak flows, through channel straightening, bank stabilization, or other river engineering techniques.
A lined drainage system also has no natural tributaries. Its main channel is open, but ..,.. it has been lined with stone, brick, or concrete.
The most highly developed channel systems have a main drainage channel completely underground in large pipes or culverts. There are no natural tributaries in these watersheds; instead, an extensive system of inlets and smaller pipes collects runoff.
The condition of the main drainage channel relates to the goals for each watershed. Stream restoration and habitat improvement can only occur with natural bed and banks: in natural or modified channels. Runoff quality measures are important for local stream quality in these same types of channels. Where stream beds have been lined or put underground, the focus on water quality is more on downstream receiving waters than on the local channel. Flood control, however, is a goal that remains important everywhere. Measures to reduce capacity problems from peak flows or to increase capacity can be taken for any kind of channel.
WATERSHED CHARACTERISTICS
The degree of development and condition of the watershed also determines what goals are appropriate for storm water management. Studies by the EPA and the Metropolitan Washington Council of Governments (MWCOG) have shown four key measures of watershed condition are land use, imperviousness, amount of forest cover, and existence of wetlands.
Land Use
In a hydrologic sense, land use is a particular combination of built up area (streets and buildings), open space (lawns, fields, and forests), and the storm sewer network. Many hydrologic calculations are based on the area of different types of land use in a watershed.
Several studies discuss the effect of land use on runoff pollution. One surprising finding was that there was no statistically significant difference in pollutant concetrations among different land uses. Differences in loadings found during sampling was primarily due to greater \~ runoff from more imperviousness rather than greater concentrations within the runoff itself. The only type of land use where significant differences were found was open, forested land. Once development occurred, pollutant concentratic:ms were essentially the same.
20 H these data are correct, it means that sources common to residential and commercial areas (for example, atmospheric deposition and street dust and dirt) are the only significant source of pollutants in any developed area. It is possible that much of the runoff pollution" in older . urban areas may be attributable to streets and traffic, and that the proportion of street surface area to total land cover may be a good indicator of potential runoff pollution.
The land use map shown in Figure 3 was derived from the U.S. Census digital TIGER file and recent aerial photography. The minimum mapping unit was the block. Each of the County's 1,852 blocks was manually assigned one of nine land use codes using 1991 color aerial photography flown at 1:7,200 scale.
Aggregation was done as necessary. In commercial corridors, blocks frequently consist of mixed land uses. Generally they were assigned the land use of the majority of parcels. Where possible, adjacent blocks with mixed uses were each assigned a different one of the uses, in order to come to a rough equivalence of the amount of each land use in an area. The percentage of each type of land use in a watershed was calculated with a Geographic Information System (GIS), using overlays of the land use and watershed boundaries. It is ' shown in Table 2.
Imperviousness
Impervious cover is the man-made surface through which storm water does not infiltrate, but instead runs off: concrete, asphalt, roofing, and similar materials. Over a century of engineering experience has established the connection between watershed imperviousness and the physical characteristics of storm runoff. Given two similar watersheds, runoff from the one with more impervious surface will have higher total volume, higher peaks, and a faster time to peak. It is also more likely to be polluted.
Imperviousness has been proposed as a key, measurable, indicator of a stream's potential health. Many studies discuss how imperviousness affects watersheds and stream quality. As it increases, the following changes can be expected:
Stream morphology Because peak flows will be higher and more frequent, and base flows will be lower, stream' channels will erode and become wider. Pools and riffles in the streambed disappear. Studies show the changes occur at approximately 10% to 15 % imperviousness. Very few watersheds in. Arlington are below this range.
Water Quality Runoff pollution appears directly related to imperviousness. As discussed above, EPA and MWCOG studies both showed that increased imperviousness resulted in more polluted runoff. At 20% to 25% imperviousness, nutrient loads exceed those of pre-development (agricultural) levels. Any conversion of forested land to pasture, crops, or impervious surface increases nutrient loads.
21 Open Space 0 SFR-Low 0 SFR- High 0 Garden Apt 151 Townhouse . Highrise Apt lnsti tutions Commercial - I nd/ Transp - Figure 3: Existing Land Use
22 } J I J } J
Open s:R s:R Garden Town- Hkise Instltu Comm- Ind/ Total ~ Space Low High Apt house Apt tional erclal Transp c:r Ci' 1100 Four Mile Run, Upper Mainstem 1 8 0 71 0 0 0 8 0 11 98 ~ 1130 Crossman Run 0 0 75 0 0 0 22 0 3 100 1150 Ohio Street Branch 0 0 99 0 0 0 0 0 0 100 ~ 1170 Westover Branch 0 0 76 3 0 0 17 4 0 100 a 1180 Four Mile Run, Upper Mainstem 2 27 0 58 2 1 0 10 0 1 100 ~ 1200 Lubber Run 7 0 59 4 11 0 5 13 1 100 a. 1300 Upper Long Branch 32 0 53 9 0 0 2 0 0 96 0::s 1400 Arlington Forest Branch 0 0 76 13 0 0 9 0 3 100 0 ""'t) 1410 Bailey's Branch 0 O· 30 49 0 16 0 0 1 96 1450 Four Mile Run, Middle Malnstem 11 0 39 33 3 2 5 1 5 99 1500 Doctor's Branch 11 0 37 26 5 1 14 4 2 100 i0. . 1600 Lucky Run 0 0 47 46 0 0 3 0 0 95 3 0 73 8 4 0 10 2 0 100 c:: 1700 Nauck Branch ~ 1720 Alexandria/Fairlington 0 0 0 83 0 0 4 12 1 100 ..... 1800 Lower Long Branch 18 0 40 11 4 1 20 3 3 100 ::s 1870 Arfington Branch 20 0 26 18 2 13 0 21 0 100 1900 Four Mile Run, Lower Mainstem 3 0 35 24 1 3 0 9 21 97 :rW tv 1980 Virginia Highlands 2 0 66 0 1 4 0 10 17 .100 w ~ 3000 Pimmit Run 32 9 53 0 5 0 1 0 0 100 ff 3600 Uttle Pimmit Run. W. Branch 0 5 73 0 3 0 19 0 0 100 Cit 3640 Uttle Pimmit Run, E. Branch 1 2 85 0 0 0 4 8 0 100 :r 3670 Uttle Pimmit Run. Malnstem 0 0 62 0 38 0 0 0 0 100 B. 3800 Stohman Run 0 0 71 0 28 0 0 0 0 100
5100 Gulf Branch 11 6 82 0 0 0 1 0 0 100 5120 Donaldson Run 34 10 55 0 0 0 0 0 0 100 5140 Rixey Branch 10 19 71 0 0 0 0 0 0 100 5160 Windy Run 1 29 48 1 0 7 13 0 0 100 5200 Spout Run 7 4 51 7 2 6 6 17 1 100 5300 Colonial Village Branch 6 0 16 39 6 10 2 12 9 100 5340 Rosslyn 18 0 0 6 13 5 0 38 21 100 5360 Rocky Run 1 0 13 26 8 7 9 30 5 100 5400 Roaches Run 10 0 8 0 3 29 1 30 20 100 5900 Parkway 58 29 0 0 0 3 0 0 3 94 5920 Cemetery/Pentagon 64 0 0 1 1 0 13 13 7 99 5960 National Airport 5 0 0 0 0 0 0 0 88 93 Habitat Habitat quality combines a number of inter-related stream health parameters, including elements of stream morphology and water quality. Habitat is measured indirectly through biological-sampling. Studies have shown that the diversity of aquatic insects, a key indicator of stream health, drops when imperviousness increases beyond 10% to 15 %. A Maryland fish survey showed loss of sensitive species such as trout at the same level, and loss of about half the native species at about 25 %.
The studies tend to show a threshold of 10% to 15% impervious, above which it is di~cu1t to maintain a stream's health at pre-development (forested) levels. At 25% impervious, streams are seriously degraded, and at 50% and above, they are essentially elements of the storm sewer network and flood control channels only.
Figure 4 shows a map of imperviousness derived from a study of LANDSAT imagery, using a ratio of the near infra-red and red bands called the Normalized Difference Vegetation Index. These values have been calibrated to a more conventional calculation based on a weighted summary of average imperviousness for nine categories of land use. They are believed to be accurate within about five percent but nevertheless are best used for relative ranking among watersheds and not as an absolute measurement. Table 3 gives estimates of the imperviousness of Arlington watersheds calculated with GIS overlays. The County as a whole is about 35 % to 40% impervious.
Forests
Forests, even in an urban area, provide many benefits for storm water management. Trees, shrubs, and ground cover intercept rainfall, reducing the volume of peak flows and lowering the erosive impact of rain. The deep layer of leaf litter and organic soils infiltrates more rainfall than other pervious surfaces, and also filters sediment and pollutants from surface runoff.
The forest understory and floor is the key to these benefits. Street trees and lawn trees by themselves don't reduce runoff through infiltration or provide the pollutant removal of a true forest. Of even more benefit is riparian forest cover -- forest along the banks of streams .. Riparian forest helps prevent streambank erosion, provides habitat and nutrients for aquatic life, and cools the stream by shading it.
A program to preserve the remaining forest cover and begin reforestation where possible could have a large positive impact on storm water management, with few drawbacks. Preservation of riparian forest is even more' critical.
The map in Figure 5 shows areas of forest cover in Arlington County, derived from aerial photography. Only areas with a natural understory and forest floor are included. A subset of riparian forest is also shown, derived with a buffer of 1,000 feet along stream channels. The percentage of forest and riparian forest in each watershed, calculated by GIS overlay, is given in Table 3.
24 ...
....
Dark: More impervious Light: Less impervious
Figure 4: Impervious Surface
... 25 Code Watershed Name Area Land Channel Trlbs Percent Percent Percent UG ImpervloLB Forested Riparian (Acrea) Use Type c-~ 1100 Four Mile Run, Upper Mall'Btem 1 651.5 SfR Hig h Modified All 29 3 3. t;" 1130 Crossman Run 228.8 SfR Hig h Underground All 31 3 0 ~ 1150 Ohio Street 8'anch 299.8 SFR Hlg h Underground All 25 0 0 1170 Westover Branch 325.4 SfR Hlg h Underground All 27 0 0 1180 Four Mile Run, Upper MalrBtem 2 1053.3 SFR High/Open Space ModlfJed AU 23 12 8 ~ 1200 Lubber Run 1015.0 SFR High ModlfJed All 37 5 3 c;,ff 1300 Upper Long B-anch 157.9 SFRHlgh/OpenSpace Modified All 25 30 29 ::r 1400 Arlington Forest &anch 85.4 SFR Hlg h Natural All 25 19 19 1410 Bailey's 8'anch 149.7 Garden Apt/SFRHlgh ModlfJed All 41 0 0 8. 1450 Four Mile Run, Middle Malnstem 898.3 SFR High/Garden Apt ModlfJed Moat 37 11 8 n::r 1500 Doctor's Branch 888.3 SFRHlgh/Garden Apt UG/ModlfJed All 34 3 2 1600 Lucky Run 140.1 SfRHlgh/Garden Apt Underground All 32 1 0 SFR Hig h Uned All 38 0 ~ 1700 Nauck &anch 233.5 1 R' 1720 Alexandrla/Fairlington 264.7 Garden Apt Unci erground All 41 5 0 ::I. 1800 Lower Long &anch 1210.7 SFR High/Others UG/ModlfJed Moat 37 4 0 a.c;, 1870 Arlington &anch 412.3 SFRHlgh/Others ModlfJed Moat 38 8 7 n 1900 Four Mile Run, Lower Malnstem 468.8 SFR Hig h/ Gard en Apt Uned Moat 45 7 0 en 1980 Virginia Hlg~lands 388.7 SFRHlgh UG/Modlfled All 39 2 1
3000 Pimmit Run 165.7 SFR High/Open Space Modified Some 9 45 28 tv UttJe Pimmit Run, W. &anch 468.1 SFR Hig h Underground All 23 1 0 0\ 3600 3640 UttJe Pimmit Run, E. &anch 521.7 SFR Hfgh/Townhouse Uned/Modlfled Moat 23 2 1 3670 Uttle Pimmit Run, Malnstem 30.0 SFR Hig h/ Modified Moat 23 0 0 3800 Stohman Run 144.3 SFR Hig h/TownhoLBe Modified Moat 23 0 0
5100 Gulf&anch 523.7 SFR Hig h Modified Moat 14 13 9 5120 Donaldson Run 654.1 SFRHlgh/OpenSpace Natural Some 11 24 18 5140 PJxey &anch 134.1 SFRHigh Natural/UG Moat 18 16 0 5160 Windy Run 318.3 SFR Hig h/SFR Low Natural Moat 21 11 11 5200 Spout Run 1123.3 SFR Hig h/Commerclal Modified Moat 39 5 4 5300 Colonial Village &anch 199.0 Garden Apt/Others Natural/UG All 51 3 1 5340 Rosslyn 95.4 Commerclal/Transp Und erground All 75 2 2 5360 Rocky Run 448.1 Commercial/Others Underground All 58 1 0 5400 Roaches Run 635.4 Commerclal/Hkse Apt Underground All 61 3 1 5900 Parkway 420.3 Open Space/s:R Low ModlfJed Some 12 47 34 5920 Cemetery/Pentagon 1228.7 Open Space Underground All 31 2 0 5960 National Airport 757.9 Transportation Und erground All 63 0 0
Total Acres 16814.7 Total Sq uare Miles 26.0 TotalCJ6
, - j I - J l ) 1 J 11 ) I 1 1 -
...
...... 4 ~. v- " -,;;
.,r ! \ \ .. \. . , ~ .... r~ '. , \ .V " \
Dark: Riparian Forest Light: Other Forest
Figure 5: Forest Cover
.... 27 Wetlands
Few of Arlington's original marshes and wetlands remain. Most were filled during land development and channel straightening many years ago. The U.S. Fish and Wildlife Service publishes the National Wetlands Inventory (NWI) maps to show where wetlands may potentially exist; these areas are shown in Figure 6. There is not enough information on their actual location and extent to estimate acreage by watershed.
Wetlands are extremely useful in storm water management, to the extent that they are being constructed as treatment systems. They provide storage to reduce peak flows and sedimentation and plant uptake to .reduce chemical and biological pollutants.
These constructed wetlands are "storm water wetlands" as opposed to natural systems. They have a different hydrology and their ecology is much simpler and less diverse than natural wetlands. Because Arlington's streams are fed primarily from storm water runoff, it is likely that any existing wetlands are more similar to storm water wetlands than undisturbed natural systems.
WATER QUALITY PROBLEMS
Background
Runoff pollution (also called non-point source, NPS, or diffuse pollution) is pollution of rivers, bays, lakes, and other receiving waters by rainfall or snowmelt moving over the ground. As water flows, it picks up pollutants from natural sources and human activity, and carries them into the receiving waters. Urban runoff can contain a significant amount of pollution. The range of pollutants found i~ runoff can be summarized in three major categories: physical pollutants, chemicals, and biological pollutants.
The physical pollutants are in general those caused by changes in watershed hydrology from urbanization. Runoff from impervious surfaces has a higher temperature than that from forest land. It is collected in storm sewers and delivered rapidly to streams, resulting in higher stream flow and velocity. These characteristics lead to erosion and sedimentation. ,~ Also, any litter thrown on an impervious surface eventually makes its way to a stream as a H floatable" pollutant.
Chemical pollutants are those most commonly thought of when water quality is discussed:
Acidity (PH) is a factor which changes the chemistry of the receiving water. Changes in pH affect the way other chemical pollutants, such as metals, are dissolved. At different pH ranges, some metals will bind to sediment and fall to the bottom as opposed to staying in solution.
Nutrients (compounds of nitrogen and phosphorus) are a factor in large, slow moving water bodies, particularly lakes. An excess of nutrients leads to growth of algae or
28 '\ ~\ \ ~." Jl
Figure 6: Potential Wetlands
29 other micro-organisms, which take up dissolved oxygen needed for shellfish and fish. The Chesapeake Bay is primarily impacted by an excess of nutrients. Arlington's small streams are not as affected because the water moves through them more quickly.
Toxics directly affect the organisms -living in the receiving water. Metals and organic pollutants damage aquatic life, becoming fatal at high concentrations. Chlorides and salts may increase salinity in streams to a point where fresh water life cannot survive.
Biological pollutants are the primary cause of public health advisories for receiving waters. Included with this category are bacteria, viruses, and the effects of other micro-organisms on oxygen levels. Bacterial levels in runoff frequently exceed standards for water contact recreation. The tests for fecal coliform and fecal streptococcus do not show every pathogen, but are used as an indirect indicator that there may be other more dangerous bacteria and -- viruses present.
Oxygen depletion is measured by two imprecise tests for Biological Oxyg~n Demand (BOD-5) and Chemical Oxygen Demand (COD). Dissolved oxygen is essential to aquatic life, and excessive organic matter can lead to the growth of micro-organisms which use it up, particularly in shallow, slower moving waters. This has been shown to be a problem in the Bay, particularly in bottom of the deeper channels.
Table 4 shows a list of storm water pollutants, with their primary sources. Runoff becomes polluted through three somewhat interrelated mechanisms: illicit discharges, atmospheric deposition, and washoff. nIicit discharge refers to any substance that enters a storm sewer system through spills, cross-connections, or improper disposal. Atmospheric deposition refers to airborne pollutants that subsequently enter receiving waters through runoff. Two forms are wetfall, which is pollutants dissolved in rain water, and dryfall which is dust and dirt that settles out of the air between storms. Wash off occurs during the storm: pollutants
~ are washed off the land into the water. I I Arlington Stream Quality
There is very little information on the quality of Arlington's storm water runoff and streams. Recent dry weather field screening and wet weather sampling of storm sewer discharges was performed for the NPDES permit application in 1992 and 1993. The Northern Virginia Planning District Commission (NVPDC) took water quality samples for 12 months in 1992 and 1993 in Four Mile Run for computer model calibration. Recently, the League of Women Voters (LWV) conducted tests for fecal coliform in Four Mile Run.
None of these sampling programs has been extensive enough to characterize runoff quality by either outfall or watershed. This lack of good monitoring data makes it impossible to estimate accurately the amount of pollution by watershed. For a planning-level analysis, a good correlation could be made with imperviousness or population density.
30 Table 4: Storm Water Pollutants and Sources
Pollutant Source
Physical Temperature Urbanization Flow Urbanization Velocity Urbanization Sediment Construction site erosion, streambank erosion Floatables Litter
Chemical Acidity Combustion products in wetfall Nutrients - Phosphorus Natural sources, fertilizer washoff - Nitrogen Combustion products in wetfall, fertilizer washoff Toxics - Metals Washoff of dryfall, leaching from acid rain - Petroleum Byproducts Washoff, spills, improper dispOsal, atmospheric deposition - Pesticides, etc. Washoff, spills, improper disposal - Chlorides Washoff of de-icing salts
Biological Pathogens Sewage connections, animal wastes, garbage Oxygen Depletion Washoff of organics (leaves, animal wastes, oil)
Field screening is a process using direct observation and inexpensive tests to identify marker pollutants for illicit discharges: odor, color, clarity, chlorine, copper, phenols, and surfactants. It was done in late summer 1991 during dry weather when no discharges should have been occurring. Of Arlington's estimated 120 major outfalls, only five showed occurrences of chlorine and surfactants, and no outfalls showed repeated evidence of copper or phenols. Based on the concentrations found and the small number of outfalls showing evidence, it appears the County does not have extensive problems with illicit discharges.
Results of wet weather outfall sampling, while not statistically significant, showed that Arlington's runoff is in the range found in national studies, with perhaps less evidence of metals and a higher level of nitrogen compounds. Results of sampling for the EPA's 128 priority pollutants showed toxic pollution does not appear to be a problem. There was only one instance of an organic toxic pollutant, the pesticide dieldrin. With the exception of zinc, all the metals found were close to the limits of detection.
31 Both the NVPDC in-stream sampling of Four Mile Run and the LWV testing indicates fecal coliform may be present in Arlington's streams. Levels were similar to those found in runoff sampled in national studies. Coliform bacteria are ubiquitous in an urban environment and are found in urban streams nationwide. Sources can include wastes from pets and wildlife, bird droppings, poor storage of h~usehold trash, and sanitary sewer breaks.
Chesapeake Bay Quality
The tidal Potomac River and the Chesapeake Bay are the downstream receiving waters for Arlington's runoff. There is more information available on their water quality than on the County's streams. Research shows the Bay's most serious problems are caused by excess nutrients, which contribute to reduced oxygen levels, less submerged aquatic vegetation and a consequent loss of habitat. Along with other Bay 'states, Virginia has made a voluntary ,fSI agreement to reduce nutrient loadings to the Bay 40% below 1985 levels.
Work done by the tributary group of VDEQ shows that 95% of Arlington's nitrogen loadings and 84 % of the phosphorus loadings come from the WPCP. Nitrogen is the more difficult nutrient to reduce; as expensive as it is to cut loadings from the WPCP, it is still cheaper per pound than removing it from runoff. While nutrient reduction from runoff is desirable, it does not appear to be the most cost-effective way for Arlington to make its contribution to the Bay program.
There is a possible exception, however. Reduction of nutrients at the source, before they enter runoff, has the potential to be very effective. Measures such as better storage of fertilizers and compost, and more effective use of the same products can be relatively inexpensive to implement but may have an impact on nutrient loads. Research to quantify the percentage of reduction from these practices is still lacking, however. FLOODING PROBLEMS ,.. To the best of DPW's lmowledge, there is no central log of drainage complaints or flooding / problems. An ·informal file is kept to assist in developing CIP projects for drainage improvements. Projects developed from these complaints are prioritized and listed in a spreadsheet matrix. The most recent of these is attached as Appendix B.
Most of the flooding problems are local in nature. They are generally the consequence of poor surface grading or undersized inlets and collector. pipes. Some of these have also come about because design standards have changed. For example, valley gutters carrying runoff through intersections were acceptable when built, but are generally not used today. Where traffic has increased since their construction, surface flow through intersections has become more of a nuisance and a hazard.
Aside from these scattered, relatively minor problems, the potential for flooding exists in watersheds with the flat topography of the Coastal Plain, and especially those at or· near sea level. These areas are as follows:
32 Ballston, Clarendon These areas are built on flat upland terrain where several watersheds join: Spout Run (South Branch), Doctor's Branch, Lower Long Branch, and Lubber Run. These are some of the most urbanized areas of Arlington, and many of the storm sewers are decades old. They may be undersized for the existing level of development.
'Crystal City. Pentagon City. Aurora Highlands Two watersheds serve these low lying areas: Roaches Run, and Virginia Highlands. They also are highly urbanized and have some sections of very old storm sewer. An additional problem is that ground elevations are only a few feet above sea level, so there·is very little slope to generate flow from the inlets· and the outfall.
One watershed has been identified with the potential for flooding because of constrictions in its main drainage channel. The East Branch of Little Pimmit Run flows through a stone lined channel which is adequate; however, culverts crossing under several roads are old, deteriorated, and undersized, causing backwaters and localized flooding.
WATERSHED PRIORITY RANKlNGS
Classification
Three of the channel and watershed characteristics described above can be used to quicldy sort Arlington's watersheds into· three groups for which the same goals are appropriate. These are: .
Existence of natural or modified channel Percent impervious Percent forested
Table 5 shows these characteristics for the portions· of the watersheds within Arlington County. Watersheds were first divided into two groups, depending on whether any natural or modified channel existed. Watersheds with these types of channel were subsequently separated into two groups of greater or less than 25 percent impervious. Note that there are essentially no watersheds less than 10 percent impervious, nor any greater than 50 percent impervious with any natural channel sections.
In general, the percent of forest cover falls in line with imperviousness, with a break at about 10 percent of forest between the less and more impervious watershed groups. Watersheds without natural stream channels also do not have any appreciable forest cover.
Some exceptions occur because watersheds are broken at the County line. Pimmit Run appears less impervious and more forested than it really is because only the small section near Chain Bridge falls within Arlington's borders, Two of its tributaries (Little Pimmit Run, Stohman Run) appear to have no forest cover even though parts of these watersheds are forested in Fairfax County. This shows rather clearly that any analysis of Pimmit Run and
33 ~
Table 5: Watershed Evaluation ~,
Area Percent Percent Riparian Natural (Acres) Impervious Forested Forest % Channel Watershed Name ~
Pimmit Run 165.7 9 45 28 Yes Donaldson Run ·654.1 11 24 18 Yes Parkway 420.3 12 47 34 Yes ,.. Gulf Branch 523.7 14 13 9 Yes Rixey Branch 134.1 18 16 0 Yes Windy Run 318.3 21 11 11 Yes ,. Four Mile Run, Upper Mainstem 2 1053.3 23 12 8 Yes Uttle Pimmit Run, E. Branch 521.7 23 2 1 Yes Stohman Run 144.3 23 0 0 Yes .., Uttle Pimmit Run, Mainstem 30.0 23 0 0 Yes Artington Forest Branch 85.4 25 19 19 Yes -.- Upper long Branch 157.9 25 30 29 Yes ,.,. TOTAL 4208.9
Four Mile Run, Upper Mainstem 1 551.5 29 3 3 Yes ,...... Doctor's Branch 888.3 34 3 2 Yes Lower Long Branch 1210.7 37 4 0 Yes Lubber Run 1015.0 37 5 3 Yes Four Mile Run, Middle Mainstem 896.3 37 11 8 Yes ~ Artington Branch 412.3 38 8 7 Yes Spout Run 1123.3 39 5 4 Yes Virginia Highlands 366.7 39 2 1 Yes ~ Bailey's Branch 149.7 41 0 0 Yes Four Mile Run, Lower M ainstem 466.8 45 7 0 Yes Colonial Village Branch 199.0 51 3 1 Yes .. TOTAL 7279.8
Uttle Pimmit Run, W. Branch 468.1 23 1 0 No /IR\ Ohio Street Branch 299.8 25 0 0 No Westover Branch 325.4 27 0 0 No
Cemetery/Pentagon 1228.7 31 2 0 No ~ Crossman Run 228.8 31 3 0 No Lucky Run 140.1 32 1 0 No Nauck Branch 233.5 38 1 0 No ,.., Alexan dria/Fairtin gton 264.7 41 5 0 No I Rocky Run 448.1 58 1 0 No Roaches Run '635.4 61 3 1 No National Airport 757.9 63 0 0 No ~ Rosslyn 95.4 75 2 2 No
TOTAL 5126.1 f=I
34 its tributaries needs to be done in cooperation with Fairfax County agencies.
Similarly, Upper Long Branch is not the heavily forested, low impervious watershed shown in the table. Within Arlington the stream flows through park land, but in Fairfax County, much of the drainage is in lined channel, with headwaters in the commercial area of Seven Comers. The stream is much more urbanized than it appears in its Arlington segment.
Four Mile Run is another exception. Its large watershed has been divided into several smaller tributaries and sections, some of which have different characteristics. For example, the Upper Mainstem #2 is in the first group of the highest quality watersheds while several of its tributaries are at the bottom. The watershed should be considered as a whole. On this basis, its characteristics are:
Percent impervious 34 Percent forested 6 Natural channel Yes
These characteristics put the whole watershed in the middle group with Lubber Run, Doctor's Branch, and most of the main stem segments.
Priorities for stream restoration
Improvement priorities for individual watersheds are based on the three groups into which they have been classified. The first group consists of watersheds whose lower imperviousness and existence of forest cover make them candidates for stream and habitat restoration. Of these, the best candidate is Donaldson Run. It has the best combination of natural channel, open space, and forest to support a native aquatic habitat. There are also no storm sewer outfalls larger than· 36 inches discharging into the stream, a situation which limits the adverse physical impacts of runoff. Donaldson Run has the further benefit of flowing almost entirely through or adjacent to park land, where it is accessible to the public for their recreation.
The next set of streams, also part of the first group, which could be improved, include Gulf Branch, Windy Run, and Unper Long Branch, which also flow through park land. The most difficult task would be to mitigate the impacts of storm sewers. All are (ed at their headwaters by large outfalls: 66-inch for Windy Run, and a combined 66-inch and 30-inch for Gulf Branch. Upper Long Branch begins as a 6O-inch outfall draining Seven Comers, then flows through a lined channel almost to the Arlington border.
One other tributary of Four Mile Run also falls into this group. Arlington Forest Branch, fed by a 42-inch outfall, flows entirely through riparian forest. It is, however, privately owned and not part of the County park system.
35 Rixey Branch has been put underground for most of its length. Unlike most streams, its tributaries are natural while the main stem is not. While the watershed characteristics are good, there is no opportunity to restore this stream.
Priorities for water quality improvements
The second group of watersheds consists of streams which flow through areas of moderate imperviousness and little forest or open space. For the most part, habitat restoration will be difficult to achieve and is not a realistic goal. Because they are open and accessible to the public, the best goal for these watersheds is to improve stream quality to allow safe water contact recreation. The streams flowing through park land should have the highest priority: Doctor's Branch, Lubber Run, and Four Mile' Run. This goal is appropriate, of course, for those streams in the first group as well.
Priorities for flood damage reduction
The third group of watersheds consists of those with no natural drainage. For these watersheds, reduction of flooding or flood damages is the most appropriate goal. One watershed which has been identified as a priority is Roaches Run. Little Pimmit Run. B. Branch, in the first group, has also been identified as apriority. Water quality measures to improve receiving waters should also be pursued in the third group of watersheds. The pollution prevention programs which are proposed in the next section would provide the most benefit and are suitable for ~y watersh~ in Arlington.
~ I
36 CHAPrER FIVE: EXISTING AND PROPOSED PROGRAMS
Arlington has previously described its storm water management programs in its 1992 and 1993 NPDES permit applications, for which many of the programs below were originally proposed. Although the permit has not yet been issued by VDEQ, some of the programs, particulary those involving pollution prevention activites and stream monitoring, are already underway.
Many of these, such as litter control and street sweeping, are not usually thought of as storm water controls. In the descriptions that follow, existing programs are shown in normal typeface and proposed programs are shown in italics. Priorities for implementating these programs are discussed in the last chapter on recommendations.
New development and redevelopment Structural controls to limit peak runoff and to reduce the pollutants, watershed protection activities prior to development, and site design standards to minimize impacts.
Construction Controls to reduce the amount of erosion during construction and subsequent sedimentation in streams.
Existing development Structural controls in older areas, such as retrofits on existing structural BMPs to provide treatment of runoff, construction of "regional" BMPs to serve existing areas, and targeted construction of water quality inlets to reduce selected pollutants.
Pollution prevention - mitigation of illicit discharges and accidental spills Activities designed to reduce dumping into storm sewers and streams or to improve cleanup once discharges have occurred.
Pollution prevention - public education and outreach Activities designed to reduce improper disposal of household chemicals, automotive products and pet wastes, and to reduce overuse of lawn care products.
Roads. highways. and bridges Reduction of the amount of pollutants on roadways before they are washed into the storm sewers. Design and construction of highway facilities to minimize environmental disruption.
Strearnbanks. wetlands, and floodplains Activities designed to reduce impacts caused by stream channel modification and to reduce erosion of streambanks. Restoration and construction of wetlands or stream habitat.
Monitoring Continuing measurement of both the quantity of flow and the water quality through instrumentation, laboratory analysis, and assessments of habitat quality.
37 NEW DEVELOPMENT AND REDEVELOPMENT
Storm water detention Arlington County does not own or operate any major structural controls for storm water management, but instead requires developers to install on-site systems where appropriate. The County has required these in the Four Mile Run drainage basin since 1975 and County-wide by ordinance enacted in September, 1976.
New development in the County is required either to include storm water detention sufficient to control the post-development peak to below the pre-development peak from the 100year storm County-wide (and the lOO-year storm in the Four Mile Run watershed) or to apply for a waiver. Approved measures include on-site detention with storage on rooftops, underground vaults, or ponds. Arlington no longer allows infiltration Best Management Practices (BMPs), due to clogging during construction.
County crews do not maintain detention structures on private property. Detention structures are inspected by the Department of Public Works Construction Management Section. One staff member inspects all the detention facilities during the months of December, January, and February. Detention structures are inspected at different frequencies, depending on the ~. type, as follows:
Infiltration 1 year Box, Pipe, or Vault 2 years Ponds 2 years Parking Lot Ponding 5 years Rooftop 10 years
When problems are found, property owners are notified and are required to clean or repair the structure as necessary. Follow-up inspections are scheduled to insure the work is done.
Chesapeake Bay Preservation Ordinance The Chesapeake Bay Preservation Ordinance ~ (CBPO), adopted May 1992, defines areas sensitive to development and redevelopment by I designating parts of Arlington County as Resource Protection Areas (RPA) or Resource Management Areas (RMA) through a zoning overlay. RPA is considered to include the entire Potomac shoreline, the major streams, wetlands contiguous to the streams and shores, and a 100-foot buffer surrounding these areas. The ordinance includes as RMA all of Arlington County which is not designated RPA.
The CBPO governs development in RP A and RMA, and therefore the entire County. New development and redevelopment where more than 2,500 square feet of land are disturbed is regulated to ensure minimum impacts on the quality of receiving waters. Non-point source (NPS) pollutant loads from new development can not exceed loading equivalent to the amount generated from 38 % impervious cover, and redevelopment must reduce the loads 10% below pre-development loading.
Acceptable NPS pollution reduction measures are:
38 - Onsite BMPs,
Compliance with a regional storm water management program,
Compliance with a storm water discharge permit pursuant to Section 402(P) of the Clean Water Act (NPDES permit), .
For completely impervious sites, restoration of a minimum of 20% of the site to vegetated open space, or
Participation in a source control plan administered by the County.
The Citizen's Guide to the CBPO includes three specific programs: site design criteria to minimize impervious area. and runoff, BMP design guidelines, and site plan review' procedures. Also, Water Quality Impact Assessments are required for all proposed development in RP A and for development in RMA if appropriate.
Revision to storm water detention ordinance The existing ordinance has a number of problems, due primarily to its narrow focus on peak flow reduction from new development. Analysis done for the NPDES permit application and the Chesapeake Bay Ordinance showed that runoff peaks from existing development far exceed anything that could be generated from new development and redevelopment. The County's storm water problems are essentially built into its existing land use. These existing uses aren't addressed in the ordinance.
Since Arlington's ordinance was written, new regulations for storm water management were issued by the State. Any updated ordinance would have to be in compliance with these regulations. Compliance, however, would have several benefits:
The State regulations provide definitions of adequate drainage and requirements for developers to meet. These would eliminate areas of uncertainty and assist County agencies in resolving problems.
An ordinance meeting the State regulations may be written to require developers to comply with a regional storm water management plan by making pro-rata payments rather than building on-site detention structures. These would be similar to the payments made into the CBPO Source Control Plan. Such a requirement would help develop a more efficient regioTUlI program for storm water management. .
A State-approved regioTUlI program can substitute for the BMP requirements in the Chesapeake Bay Ordinance, possibly allowing the County to combine the two ordinances and simplify the development plan approval process. While the CBPO is a successful implementation of the State's mandate to focus on new development and Arlington's need to reduce runoff pollution from all its land, a combined ordinance might address both the quantity and quality of runoff from existing and new development.
39 A State-approved storm water detention program is a pre-requisite if the County wants to establish a storm water utility fund.
Development Q[4esi,n criteria manual The Public Works Standards and Specifications Manual describes the materials and design details to be used for storm water facilities. Hydrologic and hydraulic design methods are not published in the same manner and may not ~ be cu"ent. This project would compare Arlington's drainage design criteria with those of I neighboring jurisdictions and with the state's Erosion and Sediment Control Manual to determine if changes are needed.
Preservation of sensitive land One method ofpreserving environmentally sensitive land is to acquire it or limit development through conservation easements or purchase of development rights. Much of the park land along Four Mile Run and the Palisades streams was acquired for this purpose many years ago. Other areas identified as environmentally sensitive could be acquired in the future as they become available.
Preservation of the remaining forested areas, and in particular, riparian forest, is strongly recommended. These types of land cover have more benefits to storm water management and stream quality that any other.
CONSTRUCTION
Erosion and sediment control (E & SC) Since 1976, Arlington County has had a program to control soil erosion, sediment deposition, and runoff from construction on sites of 2,500 square feet or more. Measures to be taken include temporary and permanent vegetation, mulching, diversion dikes, hay bale barriers, sediment basins, sediment traps, and rip-rap. Contractor training is a State responsibility and is carried out by the Virginia Department of Soil and Water Conservation.
The E & SC program is enforced by the Department of Community Planning, Housing, and Development (DCPHD) Inspections Division and the DPW Construction Management Section, which inspect construction sites on a regular basis. Inspections are carried out for developer projects in the public right-of-way by DPW and on the privately owned site by DPCHD. Between one and three hours per day are typically spent on E & SC inspection. Inspections are made once or twice a week at each site.
Enforcement measures are specified in the ordinance. Staff can shut down the site or take a violator to court. .Court has proven to be a time-consuming and less effective measure. In the last eight years, only a few subpoenas have been Served.
Clarification q,fE & SC i1lSJ)ection authority At the present time, the responsibility for inspection and enforcement of this ordinance is split between two County agencies, neither of which focuses exclusively on the issue. The Department of Community Planning, Housing, and Development (DCPHD) has authority to inspect all buildings and construction sites,· erosion control is a sideline to its other work. DP·W inspects all work done in the public
40 right-ol-way by County forces, developers, and contractors; erosion control is similarly only one part of the work..
Arlington County would study consolidating responsibility in one agency, probably DPW. It is estimated that one staff member will need to be dedicated as an erosion control specialist to be in charge of compliance, to make spot inspections, and to deal with problem sites. Current routine inspections by DPW and DCPHD would be continued, with reports to the specialist.
The County would also increase inspection of School Board and County projects for erosion cQntrol, and continue the recently begun outreach program to other County agencies to educate project managers about E d: SC responsibility.
EXISTING DEVELOPMENT
Storm sewer maintenance This program is responsible for cleaning catch basins and manholes on a scheduled basis, cleaning storm sewer blockages within 24 hours of notice, and repairing broken storm sewer line cave-ins within one week of notice. One five-man crew does all repairs and maintenance. Cleaning and preventive maintenance are scheduled so that each drainage structure is visited every 12 to 24 months. Approximately 400 are ,.a; cleaned each year.
Storm sewer capital improvements Storm drainage projects are proposed annually for the six-year Capital Improvement Program (CIP). These are built as funding becomes available. The projects are designed primarily to increase capacity of the storm sewer system or to replace deteriorated or inadequate structures.
Stonn drainage manping and inventory A project to map the County's storm sewer network has been underway for several years and is nearing completion. Pipes and structures have been digitized in GIS 'and attribute data are now being coded. Once complete, the next steps in the project will be to inventory and code information on detention systems and to delineate and digitize watershed and subwatershed boundaries.
Storm Water Modeling and Canacia Anal]sis This program will provide a detailed hydrologic and hydraulic study of each watershed. Using the watershed GIS layers and inventory created earlier, input files for the EPA Storm Water Management Model (SWMM) will be prepared. This model will be used to estimate existing flows in the larger parts of the drainage network. Pollutant loadings will be estimated for both diffuse sources and any point sources identified in each watershed.
Watershed characteristics (primarily land use and imperviousness) will be forecast and GIS layers created for anticipated future conditions. These will be used as input to the SWMM model. Proposed solutions, including sites for storm water ponds that can treat existing runoff problems, will be analyzed and compared with the SWMM model.
41 Finally, a rough estimate of costs of the proposed improvement measures would be developed for use in the CIP.
Regional BMP Feasibility Study In 1993, NVPDC issued a short investigations of site options for wet ponds in the Four Mile Run watershed. Twenty-four possible sites were identified, not all of which were feasible. This study would toke NVPDC's work to the next ,., step with an active review of these sites by County stqff and County Board commissions, I followed by scope studies and CIP proposals. To supplement NVPDC's work a similar investigation of sites in Arlington's Potomac and Pimmit Run drainage basins would be undertaken.
Storm Sewer Rehabilitation Program This progrlU!l would develop an assessment of the condition of the system and a Capital Improvement Program to begin rehabilitating or replacing the oldest and most deteriorated parts of the system. There is no cu"ent program of rehabilitation and replacement for deteriorated facilities. The County has very little iriformation on the condition or age of the storm sewer system. It is anticipated that research on the engineering records and survey field books would be the first step toward determining the age of the facilities. Inspection, either manual or with TV cameras in the lines, will follow to assess the condition. This iriformation will be input into the GIS database being developed as part of the on-going storm sewer mapping program.
After identifying the age and condition of the facilities, projects for replacement and repair will be developed and prioritized and put into the CIP for implementation.
POLLUTION PREVENTION - ILLICIT DISCHARGES AND SPILlS
Utilities Ordinance This ordinance was enacted in October, 1969, and prohibits anyone from making any connections with or openings into any part of the public storm drainage system. It also prohibits anyone from discharging sewage, chemicals, oils, tars, toxic or poisonous wastes or any substance likely to have an adverse effect on storm drains or water .~ I courses into any storm drain or open stream.
The Ordinance also prohibits disposal of any material capable Qf causing a stoppage or disrupting the flow of storm water or adversely affecting the hydraulic capacity of the watercourse or drainage structures.
Litter Article of the Garbage, Refuse, and Weeds Ordinance This Article, enacted November, 1985, prohibits littering in public or private property, including disposal of refuse, yard wastes, construction debris, oil, or offensive matter. Public property includes catch basins, county waterways and bodies of water.
Oil recycling This is a program handled by the Commonwealth of Virginia. Waste motor oil can be .taken to virtually any service station in Arlington for disposal or recycling. The Fire Department also distributes pamphlets on used oil disposal.
42 ,...
Household hazardous wastes lHHWl The Arlington Water Pollution Control Plant (WPCP) will dispose of small quantities of toxic waste materials for residents. Small amounts (less than five gallons) can be delivered during working hours on weekdays. The WPCP staff will advise residents on proper disposal of other wastes. Public education by the County on issues of HHW is also the responsibility of the WPCP.
Oil Spill Response Team A crew of County employees treats and cleans up hazardous materials spilled on roads and waterways. It works in conjunction with other jurisdictions and Fire Departments. The Team responds to an average of four to six calls per month.
Resident Alert This program is designed to make residents aware ofpollution discharges where the source is unknown. County staff can usually trace pollution to the discharge pipe or even some distance up the stonn sewer, but it is often difficult or impossible to identify the actual source. Through this program, the County would mail "alert" letters to help make residents aware that anything they pour down a gutter ends up in their parks, give notice that the County government is eriforcing its ordinances on illicit discharges, and encouraging residents to notify County agencies offuture discharges.
Hazardou£ Waste Survey This study would help quantify the potential for illicit discharges from commercial/industrial disposal of small quantities of hazardous waste. Firms generating less than 1()() kg per month are not cun-ently covered under the County's Household Hazardous Waste program or the EPA regulations on Small Quantity Generators. The County would carry out a survey of industrial and commercial sites to identify if there is a problem with disposal of small commercial quantities.
Study of maintenance procedures Other sources of runoff pollution are County maintenance activitieS, including vehicle washing, management of deicing salt and storage of recycled earth products (e.g. mulch, stone, soil, concrete). County staffwill conduct this study at the County and School Board facilities and recommend changes to eliminate or reduce pollutants.
Field screening of dry weather flows On-going sampling will be conducted in much the same way it was done for the NPDES pennit application. County staff will visually inspect all outfalls once a year during dry weather. The NPDES field screening turned up virtually no pollutants that were not detectable through sight or odor. For this reason, the County does .... not intend to do a full colorimeter test at every outfall with dry weather flow. Tests will be made of suspected illicit discharges only. Follow-up wil! consist of tracing illicit discharges upstream through the stonn sewer system U1iti1 they pan be located at a single inlet or source. . . POLLUTION PREVENTION - PUBLIC EDUCATION AND OUTREACH
Storm drain stencilling Arlington County was the first of the Northern Virginia local governments to actively embrace this program, which emphasizes the marking of catch basins on local and minor collector residential streets through the use of volunteers. By emphasizing involvement of organized groups, such as Boy Scouts, Girl Scouts and high
43 school groups, and neighborhood associations this program should both provide constant reminders and create a "pride of ownership" for the groups. The markings include: "CHESAPEAKE BA Y DRAINAGE" and "DO NOT DUMP" .
Pesticides/herbicides/rodenticide use guidelines The Department of Parks, Recreation, and Community Resources (DPRCR) reviewed its practices with these materials in 1988 and developed staff guidelines which take into account State regulations. The Department has an approved list of products and uses. Staff are trained in application methods and precautions before they are authorized to use the products. Quantities to be applied are estimated based on conditions, including weather forecasts. The guidelines at present are followed by DPRCR. DPW uses similar guidelines for its herbicide program and applicators are trained by DPRCR.
Cooperative Extension activities The Arlington Cooperative Extension program performs public outreach and education activities for homeowner use of the same materials. Booklets and flyers governing the use of pesticides, herbicides, and fertilizer are available at their . office, mailed in response to queries, or handed out at fairs and other public meetings.
Fairfax Cooperative. Extension runs programs to certify commercial lawn care firms, including all those which operate in Arlington County. The Fairfax program is certified by the Virginia Department of Soil and Water Conservation.
Environmental education DPRCR conducts an environmental education program, administered through the Conservation and Interpretation Section, which provides specialized education on water resources to school-aged children. It is designed to instill a sense of environmental awareness. Program topics include stream pollution, freshwater habitats, water quality, and pond life.
Public education Jlro~rams County staff are developing an inventory of these programs to apply to residential and commercial sources ofpollution discharges. This ejfon has included the use offocus groups, water sampling and analysis, and modeling for program effectiveness. The next step is to initiate the use of targeted iTiformation pamphlets. With the results of the previous research and the GIS property database, County staff should be position to use these pamphlets with maximum effectiveness. Specific examples ofproposed targets and the pollutants of concerns include:
Swimming pools - Educate the owners and operators on the effects of cleaning agents, such as sodium hydroxide or muriatic acid, and residual chlorine on streams to help prevent harmful impacts.
Residential lawn care - Educate the owners and residents on the effects of excessive fertilizers, herbicides and pesticides washing into the streams.
Automotive repair shops and service stations - Educate the operators on the effects of washing materials into the storm drains. Arlington County staff is concerned about
44 the amount of oil and grease entering its streams. This pamphlet would focus on a suspected 11Uljor source of that pollutant.
Hazardous waste education This program will itiform residents on the availability of the existing household hazardous waste program. Through distribution of information, such as materials identifying proper disposal and alternatives, it is hoped that the County can. not only increase awareness of how to properly dispose of waste, but also educate the public on less toxic alternatives.
Pesticide management plan DPRCR stoff are cu"ently revising the pesticide management guidelines to address issues raised in the NPDES permit application. Upon completion, stqfJ will conduct outreach to encourage th£ use ofth£ DPRCR (or oth£r similar) guidelines by all County agencies and th£ School Board. .
ROADS, mGHWAYS, AND BRIDGES
Street sWeej)ing Street sweeping removes dust, dirt, and other particulates from streets and gutters. Streets in the Rosslyn-Ballston and Crystal City commercial corridors are swept daily. .
Litter control This program encompasses hand and vacuum collection of litter in commercial areas, bus stops, and heavily travelled pedestrian routes. Collection of refuse from curbside litter cans is made through
Leaf collection This is a seasonal program to collect all leaves from County streets beginning in the late Fall. The program uses specialized vacuum trucks to collect unbagged leaves from County streets. Citizens may also place leaves in biodegradable bags for pickup by leaf crews during regular trash collection days.
STREAMBANKS, WETLANDS, AND FLOODPLAINS
Floodplain management By ordinance enacted September 1977, Arlington began regulating development in the l00-year flood plain in accordance with the National Flood Insurance Program regulations.
Existing development and land uses in the flood plain are permitted if in compliance with floodproofing provisions. New development and construction are permitted only if the effect on flood heights and flood carrying capacity' of the watercourse are mitigated by other improvements. Developers must submit an engineering study showing the effects. Variances and waivers may be applied for and granted under provisions of the ordinance.
Stream maintenance All streams are inspected annually by DPW, using a manual and checklist. Maintenance and inspection of the Four Mile Run flood control channel are required under the agreement with the Corps of Engineers. Regular vegetation removal is scheduled for the Four Mile Run Flood Control Channel each winter, with approximately
45 - S,OOO feet done annually. Other stream maintenance work is scheduled based on inspection reports.
Occasional CIP projects are designed to eliminate erosion' problems in stream channels. In past decades, these improvements enclosed or channelized streams. The County is pursuing a policy of preserving all remaining open stream channels in their natural state, to keep the aesthetic value of open streams, meet BMPs for water quality control, reduce FEMA flood ,r'*I plains, and reduce costs.
Stream bank protection The Parks and Natural Resources Division of DPRCR installs rip-rap and other materials for habitat improvement, primarily in Four Mile Run in support of the County Trout Fishing Program. Small areas are graded, rip-rapped, and replanted each year.
Four Mile Run cleanup Trout Unlimited (TU), volunteers, and DPRCR personnel clean trash out of the stream several times a year. TU has installed a variety of structures in the stream to create plunge pools and riffles, improving water quality.
Stream habitat inventory and mllllDing With this program, all open channels and streams will be inspected, classified, and mapped by type and quality of habitat for native aquatic species. Opportunities for modifications to improve habitat will also be identified.
MONITORING
In-stream Sampling A program of measurements of temperature, pH, salinity or conductivity, and total dissolved solids is proposed for eleven stream locations. Four locations represent each of the major branches of Four Mile Run, three are locations within the main channel of Four Mile Run which are the same as those used by the State Water Control Board, and one each are located in Gulf Branch, Donaldson Run, Windy Run, and Spout Run.
~ A program of biological sampling is proposed for one location within Gulf Branch, Donaldson Run, and Windy Run and two locations within Four Mile Run. The sampling is proposed to be done at the same locations each May and September. The proposed ~ technique will follow that used by the Isaac Walton League in their "Save Our Streams - Stream Quality Survey" or similar identified program. County staff will work with volunteer organizotions to encourage community involvement and watershed awareness through such a ~ monitoring program.
To identify any problems with deicing salt storage and snow removal, measurements of temperature, pH, and either salinity or conductivity will be taken at eleven stream locations qfter winter storms when salt has been applied.
Storm sewer outfall sampling A program will be implemented for continued sampling at each of the four out/alls sampled for the NPDES permit application. Using an automated sampler,
46
pat I this program will rotate the sampler between each of the out/ails to continue assembling data.
Stream raurinr and flow monitoring Successful modeling of storm sewer capacity depends on good calibration data. This program will acquire instrumentation to measure raitifall and flows to develop rainfall/runoff data in selected watersheds for use in hydrologic analysis.
47 CHAPrER SIX: CONCLUSIONS AND RECOMMENDATIONS
Three major goals for storm water management were presented earlier: to reduce flood damages, improve runoff quality, and preserve stream valleys. Progress toward these goals can be summarlzed briefly. ,., I Damages from flooding are generally at a low level. There do not appear to be any problems over a wide area. The combination of storm sewers, stream channelization (particularly in lower Four Mile Run), and on-site detention appears to have mitigated the worst problems of undersized facilities. There remain isolated instances of pipe/culvert constrictions and inadequate inlets which should be analyzed and fixed.
• It appears that Arlington's storm sewer discharges are typical of urban streams, based on national storm water monitoring data. Persistent toxic pollution does not appear to be a problem. Concentrations are below the detectable limit in all but a handful of cases. No long-term source such as cross-connection was found in field screening. TIlicit discharges to storm sewers do not appear to be a serious problem, except for sporadic discharges from spills or disposal.
Nutrients are a cause for concern for the Chesapeake Bay, but not for Arlington streams, which are not showing high levels of nitrogen or phosphorus.
Storm water runoff quantity has a major impact on Arlington streams, leaving them seriously degraded. The most serious effects are caused by high peak flows, particularly in the immediate vicinity of storm sewer outfalls. The primary source is not new construction, but existing development and the high level of imperviousness throughout the County.
Two additional conclusions are evident from the review of Arlington's storm water management activities. First is that we do not know enough about the storm sewer system, water quality, or stream condition to begin proposing structural improvements. In particular, not enough is known about runoff pollution to characterize it well. Developing the knowledge to make informed decisions is th~ highest priority.
Second, most storm water problems can be attributed to existing development and the drainage system built over the last few decades. These problems can't be fixed with controls on new development alone. Programs and projects to reduce peak flows and pollution from existing land uses should have the second highest priority.
48 The lowest priority is additions or improvements to the programs controlling storm water . from new development. With its ordinances for storm water detention, erosion and sediment control, and Chesapeake Bay preservation, the County has met the basic requirements.
The new programs describe earlier can be grouped into these three priorities. Within each group there is no particular order.. Some of the programs to develop more knowledge of the system are needed for subsequent watershed studies. In these cases, the appropriate watersheds are listed. Programs addressing existing and new d~velopment should be established County-wide and do not need to be undertaken by watershed.
SYSTEM KNOWLEDGE
1. Storm drainage inventory and map,ping Finish mapping storm sewers and detention systems and complete mapping subwatershed boundaries for all watersheds in order of priority. This program is needed' for all follow-on work.
Priority watersheds are
Donaldson Run Gulf Branch Windy Run Upper Long Branch Arlington Forest Branch Roaches Run Little Pimmit Run, E. Branch
2. Capacity analysis Develop computer models of hydrology and hydraulics for all watersheds in order of priority. This program is a prerequisite to a comprehensive CIP program.
Priority watersheds are
Donaldson Run Gulf Branch Windy Run Upper Long Branch Arlington Forest Branch Roaches Run Little Pimmit Run, E. Branch
3. Storm sewer rehabilitation program Identify age and condition of drainage facilities. This program is a prerequisite to a comprehensive CIP program.
49 ~ 4. Stream habitat inventory and maming Develop a good understanding of aquatic resources and limitations to improvements for all streams in order of priority. This program is needed to prioritize stream restoration work. /IIl\ Priority watersheds are ,.. Donaldson Run Gulf Branch Windy Run ~ Upper Long Branch Arlington Forest Branch s. Stream gauging and flow monitoring Gather data on storm water flows for watersheds in order of priority. This is needed to improve the accuracy of capacity modeling. ~
Priority watersheds are ~ Donaldson Run Gulf Branch ~ Windy Run Upper Long Branch
Arlington Forest Branch ~ Roaches Run Little Pimmit Run, E. Branch
~ 6. In-stream sampling Gather data on water quality in Arlington streams. Prerequisite to any stream restoration work.
Priority watersheds are
Donaldson Run Gulf Branch Windy Run Upper Long Branch Arlington Forest Branch Doctor's Branch Lubber Run ~ Four Mile Run
7. Storm sewer outfall sampling Gather data on water quality of runoff. Needed to ~ improve accuracy of runoff quality modeling.
". f"&'
50 EXISTING DEVELOPMENT
1. Regional BMP feasibility study Identify sites where wet ponds or wetlands could be created to reduce peak flows and runoff pollution. This effort could expand opportunities for stream restoration.
2. Revision to storm water detention ordinance Revision to incorporate state regulations, along with a watershed-based program, would allow developers to make pro-rata payments for regional detention structures rather than building on-site facilities.
3. Pollution prevention programs The programs listed below are all additions to the Chesapeake Bay Source Control Plan which would address sources of runoff pollution from existing land use. Priorities among them may vary depending on results of monitoring programs above.
Resident Alert Hazardous Waste Survey Study of Maintenance Procedures Field Screening of Dry Weather Flows Public Education Programs Hazardous Waste Education Pesticide Management Plan
NEW DEVELOPMENT
1. Preservation of sensitive land This program would help ensure that new development would not convert land which is ~tal to stream quality. This could be approached by revising definitions of RP A in the Chesapeake Bay Preservation Ordinance.
2. Clarification of E & SC inspection authority The changes proposed would end some conflicts over inspection and enforcement.
3. Development of design criteria manual A revised manual would update the County's design techniques and bring them more into line with State standards. This could be approached simultaneously with a Detention Ordinance revision.
51 ~,
BmLIOGRAPHY
CompreheDSive Plan History
Arlington County Planning Commission (1951). Arlington Looks Ahead: A Six-Year Improvement Program for Arlington County, Virginia. Arlington County Planning Commission, Arlington VA, October 1951.
Arlington County Office of Planning (1961). A Summcuy of the Master Plan of Arlington County, Virginia. Arlington County Office of Planning, Arlington VA.
Arlington Development Committee (1956). Prospectus and Work Program for a Comprehensive Plan. Arlington Development Committee, Arlington VA.
Storm Sewer Plan .History
Chester Engineers (1943). Analysis Report and Computations for a Master Plan of Storm Water Sewers. Pittsburgh, PA
Hirt, R. M. and C. G. Stoneburner (1957). Arlington, Virginia Storm Sewer Plan. Memo to the Arlington County Board.
Arlington County Planning Commission. Minutes, December 2, 1957.
Arlington County Board. Minutes, March 29, 1958.
Arlington County Board. Minutes, June 7, 1958.
Policies, Principles, Goals, Objectives, Standards
American Public Works Association (1981). Special Report No. 49: Urban Stormwater Management, APWA, Chicago, a.
Arlington County Department of Public Works (1986). Master Transportation Plan. Arlington, VA.
Arlington County Department of Public Works (1992). Sanitary Sewer System Master Plan. Arlington, VA.
Arlington County, Virginia (1993). Office of the County Manager. Principles of Siting Process and Siting Process Procedures. Arlington, VA.
Arlington County, Virginia, Department of Personnel (1911). Administrative Regulation 4.4. Arlington, VA.
52 Fairfax County, Virginia (1988). Public Facilities Manual. Fairfax County Department of Environmental Management, Division of Design Review, Fairfax VA.
Urban Drainage and Flood Control District (1969). Urban Storm Drainage Criteria Manual. Denver Regional Council of Governments, Denver, CO.
Urban Water Resources Research Council (1992). "Design and construction of urban stormwater management systems." Manual of Engineering Practice No. 77. ASCE, New York, NY.
Virginia Department of Transportation (1991). Drainage Manual. Tech Sup,plement 88-1. Richmond, VA.
Regulatory Requirements
American Association of State Highway and Transportation Officials (1911). !&ul As.pects of Highway Drainage. AASHTO, Washington, DC.
Arlington County Board (1993). "Chapter 48: Floodplain Management. I. Code of the County of Arlington County, Virginia, Municipal Code Corporation, Tallahassee, Florida.
Arlington County Board (1993). "Chapter 57: Erosion and Sediment Control." Code of the County of Arlington County, Virginia, Municipal Code Corporation, Tallahassee, Florida.
Arlington County Board (1993). "Chapter 60: Stormwater Detention Ordinance." Code of the County of Arlington County, Virginia, Municipal Code Corporation, Tallahassee, Florida.
Arlington County Board (1993). "Chapter 61: Chesapeake Bay Preservation Ordinance. I. Code of the County of Arlington County, Virginia, Municipal Code Corporation, Tallahassee, Florida.
Chesapeake Bay Local Assistance Board (1991). VR 173-02-01. Chesapeake Bay Preservation Area Designation and Management Regulations. Richmond, VA.
Virginia Department of Conservation and Recreation, Division of Soil and Water Conservation (1990). VR 215-02-00. Stormwater Management Regulations. Richmond, VA.
Virginia Soil and Water Conservation Board (1990). VR 625-02-00. Erosion and Sediment Control Regulations. Richmond, VA.
53 Watershed De6neation
Howell and Taylor, Map of Alexandria County, Virginia for the Virginia Title Co., Alexandria, 1900. Prepared by Howell and Taylor, Civil and Topographical Engineers, Washington, D.C., drawn by G.P. Strum. Washington, D.C., ca. 1900, colored, two sheets each 41 by 39 1/2 in.
Gregor Noetzel, Map of Alexandria County, Virginia. formerly part of the District of Columbia, Washington D.C., G. G. Goteler, ca. 1907, 10 by 17 in.
U.S. Dept. of Agriculture, Bureau of Soils. Soil Map: Virginia, Fairfax - Alexandria Counties Sheet, W. Edward H~, Inspector, Southern Division, soils surveyed by Wm. T. Carter, in charge, and C. K. Yingling, Jr. Base map in part from U. S. Geological Survey sheets [Washington, D.C.], Bureau of Soils, 1915, colored, 32 1/2 by 30 in.
U. S. Geological Survey, Washington and Vicinity, MD. - VA. - D.C., [Washington, D.C.], 1951, Scale 1:31,680, colored, 55 by 41 in.
U. S. Geological Survey, Washington and Vicinity, MD. - VA. - D.C., [Washington, D.C.], 1956, Scale 1:24,000, colored, 50 by 72 in.
U. S. Geological Survey, Annandale Quadrangle, Virginia, [Reston, VA], 1965, Photorevised 1984, Scale 1:24,000, colored, 22 by 27 in.
U. S. Geological Survey, Alexandria Quadrangle. Virginia - District of Columbia - Maryland, [Reston', VA], 1965, Photorevised 1983, Scale 1:24,000, colored, 22 by 27 in.
U. S. ,Geological Survey, Falls Church Quadrangle. Virginia - Marsland, [Reston, VA], 1965, Photorevised 1984, Scale 1:24,000, colored, 22 by 27 in.
U. S. Geological Survey, Washington West Quadrangle - District of Columbia Maryland - Virginia, [Reston, VA], 1965, Photorevised 1983, Scale 1:24,000, colored, 22 by 27 in. .., I Watershed Evaluation
Anderson, D.G. (1968). Effects of Urban Development on Floods in Northern Virginia. Open File Re.port, U.S. Geological Survey, Richmond, VA.
Arlington County League of Women Voters (1993). Four Mile Run: An Urban Stream. Arlington County League of Women Voters, Arlington, VA. I
54 ,..
Frost, William H. (1995)~ Delineation of Impervious Area by Remote Sensing. Master's Thesis, University of Maryland, College Park, MD.
Metropolitan Washington Council of Governments (1983). Urban Runoff in the Washington Metropolitan Area. Final Ramrt. MWCOG, Washington, DC.
Schueler, Thomas R. (1987). Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs. Metropolitan Washington Council of Governments, Washington, DC.
Schueler, Thomas R. (1992). "Mitigating the adverse impacts of urbanization on streams: a comprehensive strategy for local government." Watershed Restoration Sourcebook, MWCOG Department of Environmental Programs, Anacostia Restoration Team, Washington, DC
Schueler, Thomas R. (1994) "The importance of imperviousness," Watershed Protection Techniques, 1(3): 100-111.
u.S. Environmental Protection Agency (1983). Results of the Nationwide Urban Runoff Program. Volume I. Final rem>rt. Water Planning Division, Washington, D.C.
Virginia Department of Conservation and mstoric Resources, Division of Soil and Water Conservation (1989). Non-Point Source Pollution Assessment Re.port. VDCHR, Richmond, VA.
Virginia Water Control Board (1990). 305(b) Report to EPA Administrator and Congress for the Period July 1. 1987 to July 30. 1989. VWCB, Richmond, VA.
Waye, Don (1993). Four Mile Run Watershed In-stream Water Quality. Final Re.port. Northern Virginia Planning District Commission, Annandale, VA.
Existing and Proposed Programs
Arlington County Department of Public Works (1992). Part 1 Permit Application for Municipal Separate Storm Sewer in Compliance with National Pollutant Discharge Elimination System 40 CPR 122. Arlington DPW, Arlington, VA.
Arlington County Department of Public Works (1993). Part 2 Permit Application for Municipal Separate Storm Sewer in Compliance with National Pollutant Discharge Elimination System 40 CPR 122. Arlington DPW, Arlington, VA.
Graham, Mark B. (1994) Arlington County. Virginia Source Control Plan: First Year Report to the County Board of Arlington. Virginia. February 18, 1994.
55 ABBREVIATIONS
AASHTO American Association of State Highway and Transportation Officials ~ APWA American Public Works Association
BOD Biological Oxygen Demand BMP Best Management Practice (for storm water control)
CIP Capital Improvement Program CBPO Chesapeake Bay Preservation Ordinance COD Chemical Oxygen Demand ~ DCPHD Department of Community Planning, Housing and Development
DMF Department of Management and Finance ~I DES Department of Environmental Services DPRCR Department of Parks, Recreation, and Community Resources DPW Department of Public Works
EPA U.S. Environmental Protection Agency E&SC Erosion and Sediment Control
FEMA Federal Emergency Management Agency FY Fiscal Year
GIS Geographic Information' System GLUP General Land Use Plan
HHW Household Hazardous Waste
LWV League of Women Voters
MWCOG Metropolitan Washington Council of Governments
NFIP National Flood Insurance Program NPDES National Pollutant Discharge Elimination System NPS Nonpoint Source (type of water pollution) NVPDC Northern Virginia Planning District Commission NWI National Wetlands Inventory ~
RMA Chesapeake Bay Resource Management Area RPA Chesapeake Bay Resource Protection Area
SWCB State Water Control Board (now part of VDEQ) SWMM ~torm Water Management Model
56 TU Trout Unlimited
USGS U.S. Geological Survey ...... VDEQ Virginia Department of Environmental Quality VDOT Virginia Department of Transportation
WPCP Arlington Water Pollution Control Plant
57 APPENDIX A: FEDERAL AND STATE LA.WS AND REGULATIONS
FEDERAL LAWS, REGULATIONS,· AND PROGRAMS
Four Mile Run Watershed Management Planning Program
Authority: Section 201 of the 1965 Flood Control Act (PL 89-298) and reauthorized under Section 84 of the 1974 Water Resources Development Act (PL 93-251) Agency: Corps of Engineers Regulations: None
Congress authorized construction of the Four Mile Run Flood Control Channel with the provision that the local governments in the watershed would take measures to ensure new development would not increase peak flows in Four Mile Run. A Memorandum of Agreement was signed in 1977 which committed Arlington, Fairfax, Falls Church, and Alexandria, to review all development plans to assess the impacts of runoff and the effectiveness of proposed corrective measures. NVPDC was designated as the lead agency to manage the program using a computerized watershed model developed for analyzing the impacts.
Floodplain Insurance
Authority: National Flood Insurance Act of 1968 (PL 90-448), Flood Disaster Protection Act of 1973 (PL 93-234), 42 USC 4001 et seq. Agency: Federal Emergency Management Agency Regulations: 44 CPR 59-68, 70-73, 75, 77
The National Flood Insurance Program (NFIP) is a federal program which enables property owners to purchase insurance against flood damages as an alternative to disaster assistance. Participation is based on an agreement between local governments and the federal government, which requires the community to take specific measures to reduce flood risks. These include adopting minimum floodplain management standards which prevent new development from increasing the flood risk and protect new and existing buildings from floods. Typically, these include zoning, subdivision, or building requirements and floodplain ordinances. State governments have an agency designated to coordinate NFIP activities and assist local communities if necessary.
Wetlands
Authority: Clean Water Act, 33 USC 1344, Section 404 Agency: Corps of Engineers, EPA Regulations: 33 CFR 320, 323, 325-328, 330, 335-338, 40 CFR 230-233
58 Section 404 regulates the discharge of dredged and till materials into waters of the United States. It has become associated with wetlands because these are the types of waters most frequently affected by dredging and tilling during development. It is not a comprehensive wetlands protection program since it does not regulate all activities affecting wetlands. For example, drainage and groundwater pumping can harm wetlands without involving dredging or filling. Normal farming, silviculture, and ranching practices, as well as several other activities, are exempt by statute. States may assume a portion of this permitting responsibility. Virginia has not done so .
.... NPDES (Stonn Water Program)
Authority: Clean Water Act, 33 USC 1251 et seq., Section 402(P) Agency: EPA Regulations: 40 CPR 122.26
Section 402(P) requires the EPA to add storm water discharges to the NPDES permit program. Regulations were published in November 1990 which required industries and storm sewer operators to file applications with the State or Federal agency with permitting authority. The resulting permits govern discharges from all storm sewers owned and operated by local governments with populations of 100,000 or more, and discharges from particular industries.
Coastal Zone
Authority: Coastal Zone Management Act (PL 92-583), Coastal Zone Act Reauthorization Amendments of 1990 (PL 94-370), 16 USC 1451 et seq. Agency: NOAA, EPA Regulations: 15 CPR 923-928
The CZMA of 1972 established a program for States to develop comprehensive programs to protect coastal resources. To qualify for Federal approval and funding, the programs had to meet requirements in the regulations. The CZARA of 1990 specifically charged the State programs to address non-point source pollution affecting coastal water quality in Section 6217(g).
Dams, Dikes, and Structures in Navigable Waters
Authority: Rivers and Harbors Act of 1899, 33 USC 401 et seq. Agency: Department of the Army Regulations: 33 CFR 321-322
These regulations require anyone proposing to build a dam, dike, or any other structure or project (e.g. breakwaters, piers, weirs, pilings, navigation aids, etc.) in navigable waters to receive a permit. If interstate waters are involved, the Department of the Army issues the
59 permit with the approval of Congress. If intrastate waters are involved, the Corps of Engineers issues the permit with the approval of the State legislature.
STATE LAWS AND REGULATIONS
The following listing of Virginia laws and regulations is organized into three categories. The first is the programs and activities for which the State has granted authority and imposed a requirement on local governments. The second is programs for which the State has granted authority for local governments to take action if they wish. The last is activities which the State has expressly reserved to itself. .
Specific authority granted to local governments and required by ~tute:
Erosion and Sediment Control
Authority: 10.1':'S60 et seq. (T10.1 ChS Art4) Agency: Department of Conservation and Recreation Regulations: VR 625-02-00
This statute requires each soil and water conservation district to have an erosion and sediment control program consistent with the state program and regulations. In areas where there is no district, a county, city, or town shall adopt and administer the program.
The program consists of ordinances, policies, technical guidance, inspection, and enforcement measures which regulate land-disturbing activities and minimize erosion and sedimentation from development.
Chesapeake Bay Preservation
Authority: 10.1-2100 et seq. (T10.1 Ch 21) Agency: Chesapeake Bay Local Assistance Department Regulations: VR 173-02-01
Counties, cities and towns of Tidewater Virginia are required to establish programs which protect certain lands, referred to as Chesapeake Bay Preservation Areas, by incorporating general water quality protection measures into their comprehensive plans, zoning ordinances, and subdivision ordinances. Counties, cities, and towns are also authorized to exercise their police and zoning powers to protect the quality of state waters consistent with this chapter.
Specific authority granted to local governments but not required by statute:
Adequate Drainage
Authority: IS. 1-283 Agency: None
60 Regulations: None
This statute gives the governing body of counties, cities, and towns the power to provide for adequate drainage, to install and maintain drainage systems, and acquire land, buildings, etc., by eminent domain if necessary, to carry out this public purpose.
Health, Safety, and Welfare
Authority: 15.1-510 (TIS. 1 Ch12 Art 1) Agency: None Regulations: None
Any county maY' adopt measures to secure the health, safety, and general welfare of its inhabitants, specifically including the adoption of regulations for the prevention of the pollution of water in the county whereby it is rendered dangerous to the health or lives of persons residing in the county.
Stormwater Utility Fund
Authority: 15.1-292.4 et seq. Agency: None Regulations: None
This statute gives the governing bodies of counties, cities, and towns the power to adopt a stormwater control program consistent with 10.1-603 by establishing a utility or enacting a system of service charges. The authority is also granted to issue general obligation or revenue bonds to finance the cost of infrastructure and equipment for a stormwater control program.
Flood Damage Reduction Act
Authority: 10.1-600 et seq. (TI0.1 Ch6 Artl) Agency: Department of Conservation and Recreation Regulations: [Guidelines published]
Authorizes the Department to develop a flood protection plan for the Commonwealth and serve as coordinator of all flood protection programs and activities. The Department will also establish guidelines to meet the minimum requirements of the NFIP and make periodic inspections of local programs to determine the effectiveness of floodplain management programs and to evaluate compliance with local ordinances, rules, and regulations.
StQrmwater Management
Authority: 10.1-603 et seq. (TI0.1 Ch6 Art!. 1) Agency: Department of Conservation and Recreation
61 Regulations: VR 215-02-00
Counties, cities, and towns may establish stonnwater management programs as a local option. Effective July 1, 1990, any program must be consistent with State regulations, provide for maintenance of control devices, and be integrated with erosion and sediment control, flood insurance, floodplain management, and other programs to make compliance more convenient and efficient.
Regulations shall require that after-development runoff rates be maintained as nearly as possible to the pre-development characteristics. Design criteria to control nonpoint source pollution and localized flooding are to be established. The minimum design criteria pursuant to the Erosion and Sediment Control regulations shall be incorporated.
Comprehensive Flood Control Program
Authority: 10.1-658 et seq. (TI0.1 Ch6 Art6) Agency: Regulations:
Authorizes the expenditure of public funds and any obligations incurred in the development of flood control and other civil projects, the benefits of which may accrue to any county, municipality, or region in the Commonwealth, are necessary expenses of local and state government. Such expenditures shall be coordinated with federal, state, and local flood prevention and water quality programs and constitute the Commonwealth's flood prevention and protection. program.
Wetlands Zoning Ordinance and Wetlands Boards
Authority: 28.2-1302 et seq. (1'28.2 Ch13 Art2) Agency: Regulations:
Any co~nty city or town may adopt the ordinance specified in the statute, which after October 1, 1992 shall serve as the only wetlands zoning ordinance under which any wetlands board is authorized to operate.
Authority reserved to the Commonwealth
Darn Safety Act
Authority: 10.1-604 et seq. (TI0.1 Ch6·Art 2) Agency: Soil and Water Conservation Board Regulations: Unlatown
'..
62 Provides for State safety inspections of dams. Dams less than six feet high regardless of storage or storage of less than fifteen acre-feet regardless of height are exempt from regulation and certification.
Qwnership and Uses of Submerged Lands
Authority: 28.2-1200 et seq. (T28.2 Ch12 Artl) Agency: None Regulations: None
All the beds of the bays, rivers, creeks and the shores of the sea within the jurisdiction of the Commonwealth, not conveyed by special grant or compact according to law, shall remain the property of the Commonwealth and may be used as a common by all the people of the Commonwealth ...
It shall be unlawful for any person to build, dump, trespass upon or over, or take or use any materials from the beds of the waterways which are property of the Commonwealth, unless performed to a permit issued by the Marine Resources Commission with limited exceptions.
The Commission is authorized to issue permits for reasonable uses of state-owned bottomlands.
Control by Commonwealth as to Water Quality
Authority: 62.1-44.4 (T62.1 Ch3.1) Agency: State Water Control Board Regulations: None
The right and control of the Commonwealth in and over all state waters is hereby expressly reserved and reaffirmed.
Public Policy Regarding Waste Discharge
Authority: 62.1-44.5 (T62.1 Ch3.1) Agency: State Water Control Board Regulations: None
Except in compliance with a certificate issued by the State Water Control Board, it shall be unlawful for any person (which includes municipalities) to (1) discharge inadequately treated wastes, or (2) pollute state waters and make them detrimental to the public health, or aquatic life, or for consumption, recreation, or other uses.
Water Quality Standards
Authority: 62.1-44.15(3) (T62.1 Ch3.1)
63 Agency: State Water Control Board Regulations: None
The SWCB shall have the authority to establish standards of quality and policies for state waters and to amend or cancel any such standards.
Permit Authority
Authority: 62.1-44.15(5) (T62.1 Ch3.1) Agency: State Water Control Board Regulations: None
The SWCB shall have the authority to issue certificates for the discharge of wastes into or adjacent to state waters under prescribed conditions and to revoke or amend such certificates.
Virginia Water Protection Permits
Authority: 62.1-44 .15:5 Agency: State Water Control Board Regulations: None
Authorizes the SWCB to issue permits· for water withdrawals for domestic or other beneficial uses consistent with preserving instream flows, which themselves support other beneficial uses, including navigation, waste assimilation, wildlife habitat, and recreation.
Permits under this section constitute the certification required by Section 401 of the Clean Water Act.
Industrial Discharges
Authority: 62.1-44.16 (T62.1 Ch3.1 Art3) Agency:· State Water Control Board Regulations: None
Any owner who opens or operates an establishment from which there is a discharge of industrial wastes to state waters shall provide facilities approved by the Board for treatment and control of such wastes. Application for such discharge shall be made to the State Water Control Board.
Any owner who produces other wastes except industrial wastes and sewage (e.g. such as sawdust, garbage, refuse, oil, or chemicals) shall, at the Board's request, install facilities to prevent the discharge of such wastes into any state waters. Any owner so requested shall make an application for discharge to the State Water Control Board.
64 APPENDIX B: STORM DRAINAGE CAPITAL IMPROVEMENTS
F"'I, !
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~ 65
i1 i z STORM DRAINAGE MATRIX z 6 ) ~ U; ~ § U; iii 't ~ \U ~ ------~------October 1885 .c .!! ~ i'- in ;;; "0- j ~ ~ ~J c li ~ Point. Scat. Z ~ J - U; 0 '0 j § ~1 in .2 ':~ z.2 Q in Q z- \')~ "~ ::a; 0 - oJ ------No Impoct MIftor ..., 5rfere iii .c .c -. ·z ~ rt) o I 2 .s .c U;~ in~ 0 1c!5 C;;o 1c!5 0 j ii5 .c - .::!j=0- V; ~ I - .1.2 ~~ ~ -CD -oa 0 u - l( ":0 u ":0 vi- 8'9 - 0 0:"'; IC-, to I'nIfect TIM en .... ~& en - Sc:; :ii z C;; z- en ~~ ~ -g :i i I 0 ------SC;; c5! ~J 1! c;;en ..:~ ., - FlINN eta Wcdennaln CrouI,. at Wllllamiburg 1IwI. CD ='t ills. "!CD ~I· 'tt" ~i I: ~i C;;I en ~ a.c :! .- 'i- i: :C.c =~ch.c .. 1=~ ~~ .- 0 .• = --& - - ~ .-oJ Z-lW:- ~ ~ vi~ z! 0.. - ~~ :a 0:. vi~ Na j1 5~ z~ .... ~~ 8z ~~ I. PROPERrI DAMAGE eo.- .,.
,. noodl". 01 BIJI!dlnll U ~. , • JO ~. eo 0 , • JO 0 0 0 , • JO 0 0 0 0 _»OJ ed aclual or Calc. 'Orr PolenU.1 ~ • eo , • JO , • JO , • JO 1;:3" ,3='0
., ,~ ~ ~. JO ~. JO , ,~ , • I~ ~ • .JO 0 2. noodl". 01 Pro~rty al!tual or Call!. • Ollr .. ~ • JO .. " , . " 3 • ., J • ., . , . " , . " , • JO , . " 0 ?,~f$ Z=-3lJ 3. Ero.'on / P71:.."JL,Dama.e I~ • 3 • ., , . " , . " ~. JO ~. JO ~. JO , • .JO ~ • JO , . " ~ • JO , . " , . " , . " , . " 0 0 2,$J() Z:3D
II. RlGIn' 0' WAY DAMAGE / PUBUC INCONVENIENCE .f0'- A. noodl". 20'- •• 01 In'~ ,. Pond'n. or 10" porn ... J .,. ~ II. J .~. ' 0 . 0 .J .~ 3 .~ , " ,. ,,, 0 0 I .8 , • 8 • Inadeclluale Valley Gull.,.. , . " '''(1'... ,. . ,. '" 2~/" 2. .." 2. Eltc.a'", .p,..ad In road"ay 0 ~. ,~ ,~ 0 0 ,. ,~ ~ ,~ , ·8 0 ~ ,~ •• ,. 3. '8 , • II . 0 ~. " . , . " , . " /~r, /.1'" 3. noodl". 01 Wa'k"ap • pede.lrlan lacmu.. , • II ~ ,~ 0 , ,~ 0 ~. ,~ , • I , • II , • I 0 0 ,. ,~ •• . , . " ~ . " . ~ . " , ." J,:(, 1.:-,- B. £rwlon I DelerloraUon 20'- lOS
I. Pa.. men' ~ ~ • '0 0 0 . , · , , • '0 0 , . , 0 ~ • '0 0 ,. , ~. '0 0 (Al_ Includ.. debrl. eccumu/.Uon ••• curb "Ium_) 3 • " J • " J • " J=$ /.lIS
2. C.G ~ . , · , , ., , ., 0 , ., , • '0 0 , . , , ., , . , 0 , ., 0 ,. , , ., (Al_ Includ.. ero.lon ,,~ere no C • G ••,.b) , ." 2:10 1~5 - • 'I:. •. 3. "a'''''a,. (AJ.o lriolud.. ~e'lIfan h ••ard. and ~ ~ • '0 ,. '0 , . , , ., , ., , ., 0 , . , ,. , , ., locallon "'thin eree 0 h,." ;ped.. lrIen acUIII'y) . , . " :I • '0 , · , :I • '0 ~ • '0 , ." /=$ J ...s
... Siorm s..,.r Slruelu,... (A'.., Includ•• rep'.cemenl 01 0 ,. ~. '0 , . , , . , , ., , ., , ., , ., 0 0 0 0 old CII. or CS Pipe and olhe,. delle/enl .truolure.) , . " ,&.;.JP. J. " J • " )=15 re. .",.11 '...... , 0 w_w ,.,.,. . _w_ . ------,.J. ------ror. firs. '7. ---'53 '50 ---,., ,.15 '30 '~l ,oe ,.--- -- u U .8 .~ 1118 1V1'AL SCORE • • .I'~ /~ 58 .." ., f3 JO 17 50 ., ., J8 J' • 'S ,. $(" "it PRIORITY RANKING " " ~C1. J , , 7 e 10 13 I. 15 , 't. • " " 2 .. PRIORITY ADJUSfJlENT CRI1'ERlA " " • Unk/T1e to olher project. - See Key Abo .. ., 1Iocfere&e. more UJen I (II} II • Complaint. "UIMI'O" (If} II H • OrfIln. ~)lD}a"=., '1:r. (CA) c CoS SoC S CA C SoC C C p,C.S S C C C S S e C"S • r.,. IdenUII.., (Appro•. ) '8.) 'e7 'IN . '", '", . . . . .'S- u's ;-o.::~IO ,7'0 ,,,, aJO'. , ••0 1180 '" • Coat '.'.WUJ ".0 ,,. '. aoo'. ..,'. ,(I%D =:-,..,. '. I,D ru "eo'. "', '. '. ".15 fII.''. ,'J' '. '.:1, "es , 8 , .J 7 .e ,~ ,0.. PRIORITY ADlUSfJlENT 'e • e " " 'f " '0 '.J 1&
-) - ) -] -~ 1 ] 1 ) 1 I J ) ] ] J 1 ] ] ] ] CAPITAL PROJECT DETAIL
DEPARTMENT: Public Works TITLE: Storm Drainage
PROGRAM DESCRIPTION: The projects listed will provide needed improvements to the County's stonn drainage system to eliminate known flooding and erosion problems and to replace deteriorated or inadequate drainage structures. The projects are listed in priority order within two categories: 1) Private Property & Right-Of-Way Damage/Public Inconvenience and 2) Channel Improvements.
Through the Channel Improvements program, the County is pursuing a policy for the preservation of all open stream channels in their natural or semi-natural state. This effort is intended to become more responsive to renewed citizen interest in the aesthetic' value of open streams, meet "best management practices U for water quality control, maintain or reduce Federal Emergency Management Agency (FEMA) flood plains, and reduce construction costs.
CITIZEN PARTICIPATION: The priority of projects included in this program are evaluated based on criteria from two different categories:
• Property Damage from flooding or erosion (reported actual or forecast for ten-year potential).
• Right-of-Way Damage/Public Inconvenience such as flooding of intersections or low points, inadequate valley gutters, excessive flooding in roadways, walkways, and pedestrian facilities, and erosion or deterioration of pavement, curb, gutter, walkways and stonn sewer structures.
In each program category, citizens identify problem areas that County staff then evaluates for relative priority with other projects already in the system.
FISCAL YEAR 1997: Projects scheduled for funding in FY97 provide drainage pipes and inlets to: pickup the overland runoff from the dead end of 24th Street North which is causing erosion and flooding of the properties below the dead end (Project No.1), and pickup of the excessive runoff in South Grant Street (project No.2) and in 23rd Road/24th Street North (Project No.3) which overflows curbs and valley gutters in both streets. The first phase of the Pimmit Run Channel Improvement Project (No.4) replaces deteriorating and undersized culverts under Williamsburg Boulevard and provides channel improvements downstream.
PRIOR FUNDING: A design study for the Pimmit Run Channel Improvement projects was funded in FY 1994 ($75,000).
OPERATING IMPACT: The current maintenance budget is $350,000 for several hundred miles of stonn drainage system. There are no substantial extensions to the stonn sewer system proposed that wouleJ impact on the inventory already in place. However, operating costs may increase substantially in future years if Chesapeake Bay legislation requires treatment of collected water. Maintenance costs for new stonn se~ers is usually offset by the reduction of s~nd and debris in the system and in the. absence of cost ~ssoci~ted with stonn dam8:ge.
REVENUE SOURCES: Pay-As-You-Go funding and Bond financing is proposed, with most projects funded by bonds.
149
1 ] J 1 J I J . ] J ] . 1 ( ] ) ] ] ) 1 ] ) ) ) ] ] ] ] ) ) ] ] ] ) j ] ] ] ) ]
CAPITAL PROJECT DETAIL
DEPARTMENT: Public Works Title: Storm Drainage
BEYONr:· CAPITAL COSTS AND FINANCING (THOUSANDS) FY97 FY98 FY99 FYOO FYOI FY02 TOTAL 02 Private Property & Right-Or-Way Damage/Public Inconvenience 1. 3000 Block 24th St. N. 160 B 160 2. S. Grant St. (24th St. S. to 25th S.) 215 B 215 3. 23rd Rd./24th 8t. N. 180 B 180 4. Pimmit Run (Williamsburg Blvd. to Old Dominion Dr.) 565 B 565 5. Pimmit Run (Little Falls Rd. to Williamsburg Blvd.) 690B 690 6. N. Kenilworth St. (Washington Blvd. to 15th St. N.) 80 P 81S B 895 7. N. Pocomoke St. (3300 Block at Williamsburg Blvd.) 15 P 140 B 155 8. S. Hayes St. (23rd St. S. to 24th St. S.) 120B 120 9. 21st St. S. (S. Grant St. to S. Hayes St.) 135 B 135 10. 14th 8t. N. (N. Kirkwood Rd. to N. Lincoln S1.) 30P 250 B 280 11. N. Albemarle St. (34th Rd. N. to N. Dittmar Rd.) 25 P 275 B 300 12. Columbia Pike (S. Taft St. to S. Courthse Rd.), Phase III 180B 180 13. 2nd St. N. (Park Dr. to Henderson Rd.) & Park Dr. @ 425 P 425 3rd St. N. 14. Little Pimmit Run (N. Kensington 8t. to 34th 8t. N.) o 585 15. Project through Washington Golf & Country Club o 270 Property 16. Little Pimmit Run (Jolm Marshall Dr. to N. Kensington St.) N. o S15 Branch Channel Improvements .17. Long Branch (Troy Pa.rk), Phase I 440 18. Lubber Run (Washington Blvd. to 14th St. N.) 41S
150 CAPITAL PROJECT DETAIL
DEPARTMENT: Public Works Title: Storm Drainage
CAPITAL COSTS AND FINANCING FY97 FY98 FY99 FYOO FYOI FY02 TOTAL BEYOND (THOUSANDS) 02 19. Long Branch (26th St. S. to Troy Park), Phase II 340 20.. Long Branch (26th St. S. to 28th St. S.), Phase II 420 21. Nauck Branch 525 22. 10th St. S. Branch of Four Mile Run (S. Columbus St. to Four Mile Run) 445
TOTAL PROJECT COST- 1,120 95 1,900 55 705 425 4,300 3,955 REVENUE NET TAX SUPPORT 1,120 95 1,900 55 705 425 4,300 3,955
AS = Area Summary; please refer to Section II, Area Summaries, for more information. P = Pay-As-You-Go funding; B=Bond funding.
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