Alexandria Water Quality Master Plan

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CITY OF ALEXANDRIA MASTER PLAN

Water Quality Management

Supplement

Adopted January 13, 2001


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While the outcomes are flexible, under the Chesa-peake Bay Preservation Area Designation andManagement Regulations, the City is required toinvestigate the following areas:

(1) Constraints to Development

(2) Protection of Water Quality(3) Shoreline Protection and Erosion Control(4) Public and Private Access to Waterfront

Areas and(5) Redevelopment of Intensely Developed

Areas

A major effort in the planning process is togather background information to ensure thatadequate data is available for making environ-mentally sound decisions.As a result, the bulkof this Chapter is devoted to pulling together in-

formation from diverse sources in order to paint acomplete picture of the Citys environment. Sec-tions include:

(1) Introduction(2) Alexandrias Water Environment(3) Pollution and Other Sources of Water Qual-

ity Decline(4) Water Quality Management Today

This information then serves as the basis for Sec-tion V, Policy Analysis and Action Plan. SectionV takes a strategic look at how Alexandrias wa-ter quality programs and regulations meet thechallenges laid out in Sections I through IV.

The following is a summary of the importantfindings which are explained in more detail inSection V Policy Analysis and Action Plan.

Section V also includes a table identifying timeframe for completion, cost, and the City agencyresponsible for implementation. New actions,or those which are not ongoing City programs,are shown in bold.

SMALL AREA PLANS. Most detailed landuse planning is accomplished through theCitys fourteen Small Area Plans.

To provide a stronger link between eachSAP and this Supplement, the City will

incorporate into each SAP: a discus-sion of the Citys long-range water qual-ity protection strategies; SAP-specificChesapeake Bay Preservation Areamaps; and, SAP-specific analyses ofopportunities to protect and improvewater quality and the environmentthrough planned development and re-development opportunities.

EXISTING CITY ORDINANCES. TheCitys Chesapeake Bay Preservation Or-

dinance, Erosion and Sediment ControlOrdinance, and Floodplain Overlay Districtand the Virginia Uniform Building Code al-ready provide a sound foundation for wa-ter quality management in Alexandria.

The City will consider incorporating civilpenalties into its CBPO as a way tostrengthen local enforcement.

TARGETS OF OPPORTUNITY URBANRETROFIT PROGRAM.The Departmentof Transportation and EnvironmentalServices Targets of Opportunity UrbanRetrofit Program is an important public-pri-vate partnership which has resulted in sig-nificant water quality benefits by control-ling pollution from already developed ar-eas of the City. This program will continueAlthough urban, Alexandria is still an important

part of the Chesapeake Bay ecosystem.

SIGNIFICANT FINDINGS


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to be used to improve water quality andhelp the State to meet its nutrient pollutionreduction obligations under the federalChesapeake Bay Program.

WETLANDS. Wetlands are an important,but disappearing, resource in the City.

The City will support efforts, similar tothe Targets of Opportunity Urban Ret-rofit Program, that promote the resto-ration of degraded wetlands andstreams. In addition, while healthy wet-lands should generally be left alone, whenimpacts do occur the City will try to miti-gate the impacts through wetland cre-ation or enhancement, improvements toriparian areas, or through the use ofcreative Best Management Practices totreat stormwater. The City will investi-gate opportunities to use wetlands asan educational tool for both studentsand adults.

HABITAT PROTECTION. Wildlife habitatprotection is a major challenge in Alexan-dria. The City will better identify, char-acterize, and map remaining significantnatural habitat areas that will assist theCity with its effort to preserve and pro-

tect these areas. When possible, exist-ing stream valleys need to remain in a natu-ral condition.

Remaining wildlife habitat areas are frag-mented and ways to connect remaininghabitat areas need to be explored. If cur-rent efforts by VDOT to reduce the impactof streets on wildlife corridors are success-ful, the City will pursue developing simi-lar standards for new or reconstructedCity roads.

WASTEWATER TREATMENT. The Alex-andria Sanitation Authoritys effort to up-grade Alexandrias Wastewater TreatmentFacility is probably the single most impor-tant, and costly, environmental protectioneffort in Alexandria. The City will support

this effort and ensure that citizens un-derstand the important role that the up-grade plays in the protection of Chesa-peake Bay water quality. The City willcontinue to meet and exceed the require-

ments of its permit to operate a combinedsewer system. The City will continue itsefforts to minimize the number and volumeof combined sewer overflows. The City willcontinue its sanitary sewer inspection andmaintenance program in an effort to elimi-nate sanitary sewer overflows.

WATER QUALITY MONITORING. Thefour primary pollutants of concern in theCity include fecal coliform bacteria, nutri-ents, petroleum products (oil), and thermal(heat) pollution. Current efforts by theCity to control these pollutants need tobe expanded and there is a need to bet-ter characterize City water quality.

Specifically, current water quality monitor-ing efforts are not adequate to detect pol-lution pulses associated with dumping andstormwater runoff. The City will initiate aprogram to expand the scope of exist-ing water quality monitoring efforts. TheCity will also pursue public-private part-nerships and volunteers to assist in

monitoring water quality in the City.

POLLUTION PREVENTION. Pollutionprevention is the most cost-effective wayto protect water quality. Existing City pro-grams include its street sweeping program,leaf collection program, hazardous wasteand used oil collection program, sanitarysewer line inspection and maintenance pro-gram, school-age water and environmen-tal education programs, and best manage-ment practices manual for automotive re-

lated industries.

While the City has undertaken importantpollution prevention efforts, an expandedand comprehensive approach to pollutionprevention is needed. Before the year2007, the City will need to demonstrate,


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under new federal Clean Water Act require-ments, that it is minimizing pollution throughpublic education and outreach programs.

Areas specifically identified as requir-ing attention and public outreach by theCity include the following.

The City will coordinate with fuel oilcompanies to increase public aware-ness of the threat of aging aboveground and underground storagetanks.

The City will continue to work withthe Virginia Department of Environ-mental Quality to prevent under-ground storage tank releases.

The Health Department will continueto require that homes with failingseptic systems connect to the sani-tary sewer.

The City will develop a strategic planfor reducing fecal coliform bacterialevels in Alexandrias streams basedupon recent DNA test findings.

The City will invite the Virginia Ma-rine Resources Commission to ad-dress City officials and local marinaoperators about ways to prevent

pollution. The City will encourage methods to

reduce the impacts of thermal pol-lution on streams. Options includeworking with businesses to promotealternatives to dark impervious sur-faces (light colored roofing materi-als and asphalt or using greenroof technologies) and the more ef-fective use of parking lot trees tocool impervious surfaces. The Citywill invite the Virginia Cooperative

Extension to assist the City in put-ting together a strategic plan for re-ducing pollution from lawn and gar-den care practices while maximizingthe use of existing resources.

The Citys web page will be used as ameans of advertising environmentalprograms and for exchanging envi-ronmental information.

USED OIL AND ANTIFREEZE RECY-CLING.There is a need for additional par-ticipation in used oil and antifreeze pro-grams. The City will increase advertis-ing of collection sites as a way to en-tice businesses to join the program.

OPEN SPACE AND VEGETATION. Animportant way to reduce nonpoint sourcepollution is to increase the amount of openspace left in vegetation. The Citys openspace requirements do not currently con-

tain a requirement that a percentage ofopen space must be vegetation. The Citywill investigate setting guidelines forestablishing a minimum percentage ofvegetated open space to satisfy Cityopen space requirements.

FLOOD CONTROL AND STREAMBANKEROSION. Most of Alexandrias water-ways have been hardened or channelizedto stabilize eroding stream banks and toincrease carrying capacity. Balancing the

need to provide flood control with a desireto promote wildlife habitat is among themost difficult problems faced by the City.

The City will address erosion problemson a site-specific basis in recognitionof the need for flexibility. A wide rangeof options will be explored by the Cityin addressing a particular erosion prob-lem with the goal balance the need tominimize flooding, reduce erosion, andprotect wildlife habitat. Options include,

but are not limited to:

bioengineering stream bypass natural stream adjustment and stream hardening


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Management of already hardenedstreams is also a difficult issue for the City.Flood control channels must be kept clearin order to prevent flood damage to down-stream businesses and residents.

The City will, on a site specific basis,consider planting high-canopy vegeta-tion above the 100-year flood level inorder to provide wildlife habitat andscreening while not impacting on thephysical integrity of the flood channel.

STREAM CORRIDOR MANAGEMENT.Most of Alexandrias streams serve mul-tiple functions, including flood control,buffering between land uses, and wildlife

habitat. Many of these streams are alsodesignated Resource Protection Areas.Unfortunately, these functions often comein conflict with each other.

The City will develop an evaluation pro-cedure for dealing with stream corri-dor management issues when theyconflict with Chesapeake Bay preser-vation and wildlife habitat goals. TheChesapeake Bay Local AssistanceDepartment will be consulted to ensure

that it is compatible with the Chesa-peake Bay Preservation Area Designa-tion and Management Regulations.

Most of Alexandrias tributaries lack a veg-etative buffer that helps to protect waterquality. Because of limited opportunitiesfor revegetation of denuded stream buff-ers, the City will identify, characterize,and map streams that have limited orno vegetation but have the potential tobe restored by public or private means.

POTOMAC RIVER SHORELINE.A largemajority of the Alexandria Potomac wa-terfront is hardened with rip rap and bulk-heads. Some bulkhead areas have beenidentified as being in poor condition. Di-lapidated bulkheads must be ad-

dressed by a developer during anywaterfront redevelopment project. It isanticipated that planned redevelopmentalong the shoreline will result in the reha-bilitation of most of the Citys dilapidatedbulkheads.

POTOMAC RIVER PUBLIC ACCESS.The City recognizes the value of ensuringthat there is adequate public access to thePotomac River shoreline. A subcommit-tee of the Waterfront Committee and theParks and Recreation Commission con-tinue to make specific recommendationsfor the few remaining undeveloped or non-conforming waterfront parcels.

Planning efforts will continue to takeinto consideration the need to properlymanage and protect sensitive naturalresources with the goal of achievingincreased opportunities for public ac-cess.

ENVIRONMENTAL COORDINATIONAND PUBLIC OUTREACH AND EDUCA-TION. New federal Clean Water Act man-dates will require the City to demonstratethat it is develop outreach programs to in-

form individuals and households aboutsteps that can be taken to reducestormwater pollution. In addition, whilemany of the Citys departments have takenon outreach programs to address specific,acute problems, there is a need for over-all coordination of City efforts.

To reduce redundancy, and to focus Cityoutreach efforts in a cohesive manner, theCity will establish an EnvironmentalCoordination Group (ECG) with repre-

sentation from the departments ofTransportation and Environmental Ser-vices, Planning and Zoning, and Rec-reation, Parks and Cultural Activities.Other departments or organizations willparticipate as needed. The Environmen-tal Coordination Group will facilitate the co-


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ordination of environmental and publiceducation and outreach programs, includ-ing the use of the Citys web page to shareenvironmental information with the pub-lic. This group will also facilitate the re-

view of environmental impacts of signifi-cant projects in the City.

FUNDING OPPORTUNITIES.While pol-lution prevention is more cost-effectivethan cleaning up pollution after the fact, itcosts more in the short-term. There are anumber of funding mechanisms availablethat can be used to raise revenue to imple-ment State and federal mandates as wellas locally identified stormwater manage-ment projects and programs. The City

will:

investigate for adoption a pro ratashare stormwater program

monitor the continued implementa-tion of stormwater utility programsin other jurisdictions and

continue to pursue grant fundingfor specific environmentalprojects


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Water Quality ManagementCITY OF ALEXANDRIA MASTER PLAN

Table of Contents

I Introduction............................................................................ 1I.1 Purpose and Enabling Authority ............................................. 2I.2 Opportunities to Make a Difference ........................................ 3I.3 Approach and Organization .................................................... 4

II Alexandrias Water Environment........................... 5II.1 A Brief Water History .............................................................. 6II.2 Watersheds and Water Resources ......................................... 7

Surface Water Quality............................................................. 7Stream Bank Erosion and Stream Buffers.............................. 12Potomac River Shoreline ........................................................ 15Wetlands ................................................................................. 17Groundwater ........................................................................... 17Potable Water Supply and Water Supply Protection .............. 18

II.3 The Land and Land Forms ..................................................... 19Topography ............................................................................. 19Geology and Soils .................................................................. 19

II.4 Wildlife and Natural Habitats .................................................. 20Habitat Fragmentation ............................................................ 24

II.5 Public and Private Access to Waterfront Areas ...................... 24

III Pollution and Other Sources of WaterQuality Decline.................................................................... 29

The Role of Redevelopment in Water Quality Improvement .. 30III.1 Point Source Pollution ............................................................ 31

NPDES Discharges ................................................................ 31Wastewater Treatment............................................................ 31

Combined Sewer System ....................................................... 32Leaking Sanitary Sewer Lines ................................................ 33Above Ground and Underground Storage Tanks ................... 34Septic Systems....................................................................... 36

III.2 Nonpoint Source Pollution ...................................................... 36Wildlife, Non-Migratory Waterfowl, and Pet Waste ................. 39

III.3 Erosion of the Land ................................................................ 39


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III.4 Air Pollution ............................................................................ 39III.5 Waterfront and Dock Activities ................................................ 39III.6 Areas of Special Concern ....................................................... 40

Potomac Yard ......................................................................... 40Cameron Station..................................................................... 41Alexandria Gas Works/Oronoco Site ...................................... 42Bogle Chemical Company Site ............................................... 43Municipal Land Fill Sites......................................................... 44Other Hazardous Contamination Sites ................................... 44

IV Water Quality Management Today...................... 45IV.1 City Master Plan ..................................................................... 46

Future Land Use Plan and Map.............................................. 46IV.2 City Ordinances and Regulations ........................................... 46

Chesapeake Bay Preservation Ordinance ............................. 47Erosion and Sediment Control Ordinance .............................. 48Flood Control and Floodplain Overlay District ........................ 48

Regulation of Trees, Shrubs, Plants, and Vegetation ............. 49Regulation of Dog Waste and the Prohibition of Disposalof Refuse and Debris into Storm Sewers .......................... 49

Prohibition of Dumping Hazardous Wastes IncludingUse Oil .............................................................................. 50

Prohibition of Automobile Maintenance on City Streets.......... 50Zoning Ordinance Development Approval Procedures .......... 50Procedures for the Control of Contaminated Land ................. 51

IV.3 City Programs......................................................................... 51Street Sweeping/Flushing and Catch Basin Cleaning

Program ............................................................................ 51Targets of Opportunity Stormwater Retrofit Program ............. 52

Best Management Practices Manual for AutomobileRelated Industries ............................................................. 53Hazardous Waste and Used Oil Collection Programs ............ 54Leaf Collection Program ......................................................... 54Sanitary Sewer Line Inspection and Maintenance Program... 55School-Age Water and Environmental Education Programs .. 55

IV.4 Alexandria Sanitation Authority ............................................... 55IV.5 State, Federal, and Regional Programs ................................. 56IV.6 Community Programs ............................................................. 57

Alexandria Earth Day.............................................................. 57

V Policy Analysis and Action Plan............................. 59Role of Small Area Plans........................................................ 59

V.1 Constraints to Development ................................................... 60Wetlands................................................................................. 60Topography ............................................................................. 60Geology and Soils .................................................................. 60Wildlife Habitat Corridors ........................................................ 62Stream-Side Vegetation.......................................................... 62


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Floodplains ............................................................................. 62Groundwater Recharge Areas ................................................ 62

V.2 Protection of Water Quality ..................................................... 63Need for Regional Coordination ............................................. 63Point Source Pollution ............................................................ 63Nonpoint Source Pollution ...................................................... 64

Thermal Pollution.................................................................... 66Water Conservation ................................................................ 66Erosion of the Land ................................................................ 67Air Pollution ............................................................................ 67Waterfront and Dock Activities ................................................ 67Areas of Special Concern ....................................................... 67

V.3 Shoreline Protection and Erosion Control .............................. 67Stream Bank Erosion Control and Stabilization...................... 67Stream Corridor Management ................................................ 68Potomac River Shoreline and Bulkhead Management ........... 68

V.4 Public and Private Access to Waterfront Areas ...................... 69V.5 Redevelopment Areas ............................................................ 69V.6 Overall Outreach and Coordination ........................................ 69V.7 Potential Funding and Enforcement Mechanisms .................. 70

Pro Rata Share Off-Site Drainage Facility Program ............... 70Stormwater Utility ................................................................... 71Grant Opportunities ................................................................ 71Chesapeake Bay Preservation Act Civil Penalties ................. 72

V.8 Implementation Summary and Time-Line ............................... 72

VI Acronyms.................................................................................. 81

FIGURES

I.1 Location of the City of Alexandria with Respect to the ChesapeakeBay and Tidewater Virginia ..................................................... 3

II.1 View of Hunting Creek from Shuters Hill 1864 ................... 6II.2 Major Streams and Watersheds of Alexandria ....................... 8II.3 Watersheds at a Regional Perspective................................... 9II.4 Fecal Coliform Trends in Cameron Run and Four Mile Run... 10II.5 Sources of Fecal Coliform Contamination in Four Mile Run... 10II.6 Natural, Artificially Hardened, and Severely Eroding Stream

Reaches ................................................................................. 13

II.7 Inventory and Condition of Potomac River ShorelineStabilization Structures ........................................................... 16

II.8 Generalized Alexandria Soils Map.......................................... 21II.9 Alexandrias Own Threatened Species The Wood Turtle .... 22II.10 Wild Celery A Common Species of Aquatic Vegetation on

Alexandrias Waterfront .......................................................... 23II.11 Map of Existing and Potential Marina and Boat Docking

Areas and Public and Private Waterfront Access Points ........ 27


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III.1 Location of Alexandrias Combined Sanitary Sewer System.. 32III.2 Point Source Pollution Map and Special Areas of Concern.... 35III.3 Alexandrias Industrial Heritage 1877 Map Showing City

Gas Works and Other Industrial Uses .................................... 40

IV.1 No Dumping Signs Along a Residential Street ..................... 50

IV.2 Alexandria Street Sweeper ..................................................... 52IV.3 Targets of Opportunity Stormwater Retrofit Program Sites .... 53IV.4 Public Education Materials Help to Provide Information

on Alternatives to Dumping..................................................... 54IV.5 Chesapeake Bay Education Plaque at Oronoco Park ............ 56

V.1 Generalized Constraints to Development Map ....................... 61

TABLES

II.1 Options for Addressing Impaired Streams .............................. 14II.2 Alexandrias Soils and Suitability for Development ................ 20II.3 Existing and Potential Marina and Boat Docking Areas

and Public and Private Waterfront Access Points................... 26

III.1 City Land Uses and Associated Imperviousness.................... 37III.2 Common Urban Pollutants and Their Sources ....................... 37

MAPS

City Wetland MapMarine Clays and Steep SlopesPotential Development Sites

Chesapeake Bay Preservation AreasFloodplain Overlay District

All maps located at the back of the document.


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Water Quality ManagementCITY OF ALEXANDRIA MASTER PLAN

IntroductionI

Citizens and Visitors Enjoy

Alexandrias Waterfront

Colonial Alexandria was founded as a link be-tween the land and the water. Today, the linkagebetween the City and the water has never beenstronger as citizens and visitors alike enjoy the

natural and man-made beauty of Alexandriaswaterfront. Forested stream valley parks locatedthroughout the City provide passive recreationalopportunities for residents and habitat for wild-life. All of Alexandrias waterways, including itscreeks, streams, drainage ditches, and culverts,are part of the larger Chesapeake Bay ecosys-tem. However, Alexandrias two and a half cen-turies of residential, commercial, and industrialdevelopment and activity has not occurred with-out cost. Urban development and associatedhuman activities have contributed to the steady

decline of local and regional water resources including the Potomac River and the ChesapeakeBay.

Because of Alexandrias historic and continuingreliance on the water for trade, food, and recre-ation, it is a particular point of pride that Alexan-dria has committed itself to the stewardship of itswater and other natural resources. The purposeof this Master Plan supplement is to recognizethe interdependency between people and theirenvironment and to guide the City as it seeks to

protect and restore its own numerous local tribu-taries as well as the natural habitats of the Chesa-peake Bay and the Potomac River that are de-pendent on the water quality in these tributaries.

CONTENTS Purpose and Enabling

Authority Opportunities to

Make a Difference

Approach and

Organization


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It is the intention of the City, using this supple-ment as a tool, to:

restore impaired streams that are capableof supporting diverse aquatic habitats

protect streams that currently support

aquatic life from the effects of improper de-velopment and pollution and

provide residents with a wide-range ofopportunities to interact with and becomestewards of their natural environment

Through these efforts, the City anticipates beingable to continue to make a substantive contribu-tion to the restoration of the Chesapeake Bayand to the improvement of the overall quality oflife for the residents of the City of Alexandria.

PURPOSE AND ENABLINGAUTHORITY

I.1

The Chesapeake Bay Alexandrias downstreamneighbor is among the nations largest and mostproductive estuaries. However, carried along withthe huge volumes of fresh water from the Bays64,000 square mile watershed are sediments,fertilizers, pesticides, motor oil and other pollut-ants generated by various land uses and humanactivities. As the population of the ChesapeakeBay watershed has grown (from 6,353,800 in 1950to 13,591,150 in 1990, a 113% increase), so toohave the impacts of these pollutants on the healthof the Bay.

Today, many once-plentiful aquatic species, in-cluding sturgeon, striped bass, oyster, blue crab,and many species of waterfowl, have reachedcritically low numbers. According to the Chesa-peake Bay Program, American shad, once themost commercially valuable species of the Chesa-

peake Bay, declined from Bay-wide landings av-eraging more than 5 million pounds per year formost of the twentieth century to only 47,000pounds in 1993 and 129,482 pounds in 1994. The1993 oyster harvest of 592,000 pounds was onlyone percent of the peak harvests at the end ofthe 19th century. In addition to the decline of these

commercially valuable species, submergedaquatic vegetation (SAV), which provide food andhabitat for many aquatic species, also declinedsharply during the 1960s and 1970s as a resultof increased nutrient and sediment pollution fromdevelopment of the surrounding watershed.

Population within the Chesapeake Bay watershedis expected to grow by an additional 931,950people to 14,532,100 from 1990 to 2000.

In 1983, Virginia, Pennsylvania, Maryland, theDistrict of Columbia, and the U.S. EnvironmentalProtection Agency signed the Chesapeake Bay

Agreement and created the Chesapeake BayProgram to help find ways to restore the Bay. InVirginia, the most widely recognized result of thisagreement is the Chesapeake Bay Preservation

Act of 1988 (Sections 10.1-2100, et seq., of theCode of Virginia (1950)). The City of Alexandriaimplemented the Act in 1992 in the form of itsChesapeake Bay Preservation Ordinance whichrequires developers to meet pollution reductionand minimization through performance criteriaduring the development and redevelopment pro-cesses.

In addition to requiring the development of aChesapeake Bay Ordinance, the Act (Section10.1-2109.B) also states that Counties, cities, andtowns in Tidewater Virginia shall incorporate pro-tection of the quality of State waters into eachlocalitys comprehensive plan consistent with theprovisions of this chapter. The purpose of incor-porating water quality protection into local com-prehensive plans is to account for what is alreadybeing done to help protect water quality and toprovide a framework for expanding these effortsin a way that helps all Virginians to meet environ-mental, social, and economic goals.

This Water Quality Management supplement tothe Citys Master Plan constitutes Alexandrias

long-range vision for a cleaner water environmentand sets forth policies, strategies, and time-linesto achieve its identified water quality protectiongoals.


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In general terms, urban pollution can be reducedthrough the application of four principles.

Impervious surface area necessary to ac-commodate desired land uses should beminimized.

Existing vegetation should be preserved andrestored to the maximum extent practicable.

Human behavior that results in pollutionshould be challenged and changed throughpublic education.

Pollution that cannot be reduced throughchanges in human behavior should be con-trolled by employing technology or by install-ing stormwater management pollution re-duction facilities (also known as best man-agement practices, or BMPs).

While Alexandria has been urbanized for sometime, there are still many opportunities for the Cityto actively reduce pollution. In fact, continuedgrowth and economic prosperity provides the prin-ciple means for improving water quality and habi-tat conditions in the City. Between 1990 and 2000,the City is estimated to have grown by 10% from111,183 to 123,200 residents. Office space grewfrom 13,563,581 to 14,067,111 square feet from1995 through 1998. Most future residential and

OPPORTUNITIES TO MAKE ADIFFERENCE

I.2

Urban areas such as Alexandria contribute sig-

nificantly to water quality problems. Not only doesurbanization introduce a myriad of new pollutantsinto the environment, it significantly alters thelands ability to assimilate these pollutants. Asforests and meadows are converted to parkinglots, driveways, roads, roof tops and sidewalks,the surface of the land becomes increasingly im-pervious. This means that any pollutants thatcollect on these surfaces as a result of humanactivities are flushed directly into local streamswithout the cleansing benefit of infiltration into thesoil or filtration by vegetation.

FIGURE I.1Location of the City of Alexandria

with Respect to the Chesapeake Bay

and Tidewater Virginia

Washington D.C.

PR. GEORGE

MIDDLESEX

YORK

WESTMORELAND

ACCOMACK

LANCASTER

ESSEX

CHESTERFIELD

HENRICO

HANOVER KINGWILLIAM

KINGandQUEEN

GLO

UCESTE

R

MATH

EWS

NEW KENT

JAMESCITY

SURRY

SUFFOLK

NORTHUMBERLAND

ARLINGTON

FAIRFAX

STAFFORD

CAROLINERICHM

OND

SPOTSYLVANIA

NORTHAMPTON

PR. WILLIAM

KINGGEORGE

ISLE OFWIGHT

CHARLESCITY

PotomacRiver

Ches a

pea

k e

Ba

y

Chesapeake

Colonial Heights

City of Alexandria

Hampton

Hopewell

NewportNews

Norfolk

Poquoson

Portsmouth

Richmond

Suffolk

Virginia Beach

Williamsburg

Falls Church

Fredericksburg

Fairfax


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commercial development, with the exception ofa few significant parcels, is expected to come inthe form of redevelopment. From a resourcesmanagement perspective, this is particularly sig-nificant because a majority of the Citys residen-tial and commercial areas were developed prior

to the implementation of stringent water qualityregulations (over 43% of housing units were builtprior to 1960 and over 89% were built prior to1980).

Through a combination of creating new develop-ment that is sensitive to water quality and naturalhabitats, retrofitting existing development withwater quality controls when possible, and pro-viding the tools for residents and businesses tobecome better stewards of the environment, Al-exandria can and is already making real contri-

butions to the protection of local water resourcesand the Chesapeake Bay.

APPROACH AND ORGANIZATION

I.3

This supplement takes the approach that to ar-rive at achievable water quality goals, strategies,and action plans, it is necessary to have a de-tailed understanding of the Citys natural envi-ronment and existing City, State, and federalregulations and programs intended to help pro-tect water quality and the environment. By com-paring identified constraints to development, sen-sitive natural resources, and existing and poten-tial sources of pollution with existing programs, itis possible to visualize areas of the Citys waterquality protection programs that may require fur-ther study and analysis.

To help foster this approach, this supplement isdivided into the following sections:

I. IntroductionII. Alexandrias Water EnvironmentIII. Existing and Potential Sources of

Water PollutionIV. Water Quality Management TodayV. Policy Analysis and Action Plan


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Alexandrias Water EnvironmentII

Alexandrias Resilient Wildlife

Habitat at Route One Interchange

Located on the tidal Potomac River approxi-mately six miles south of downtown Wash-ington D.C., Alexandrias natural and man-made environments are undeniably inter-twined. Having experienced numerous wavesof urbanization since its founding in 1749, theCity contains very few natural resources that

have not been affected by human activities.Remarkably, however, Alexandria is home toa hardy, if limited, natural ecosystem. Pock-ets of wildlife can be found in back yards,stream valleys, and even Alexandrias streettrees and utility line rights-of-ways. More im-portantly, Alexandria serves as part of thelarger Chesapeake Bay ecosystem.

Alexandrias efforts to promote conservationand environmental stewardship within itsboundaries serves as an integral part of largerChesapeake Bay preservation efforts.

To promote future development and redevel-opment that complements the remaining natu-ral resources of the City, improves habitatconditions where possible, and enhances theoverall quality of life for City residents, it isfirst necessary to identify and understand ex-isting natural environment and the potentialconstraints to human activities that they rep-resent. The following section provides a sum-mary of natural resources and environmentalfeatures affecting water quality that are unique

to Alexandria as well as those which areshared with its neighbors Fairfax County andArlington County.

CONTENTS A Brief Water History Watersheds and Water

Resources The Land and Land

Forms Wildlife and Natural

Habitats Public and Private

Access to WaterfrontAreas


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tures. Lower Backlick Run (from Indian Run east)was first channelized around 1850. The CameronRun channel was completely reconstructed dur-ing the early 1980s, in conjunction with the wid-ening of the Capital Beltway.

A 1974 report entitled The Fauna of the CameronRun Watershed, Fairfax County Virginiadescribesan extensively altered watershed in which mostopen space and forest was confined to floodplainareas. While deer, fox, beavers, and otters hadlargely disappeared, some muskrat still called thewatershed home and raccoon could be found inabundance. A survey of aquatic species foundthat many of the more pollution intolerant spe-cies had disappeared, especially when comparedto the then relatively undeveloped Pohick Creekwatershed to the west. However, even in 1974,

none of the twenty Cameron Run watershed sam-pling sites was so polluted as to have a completeabsence of pollution intolerant aquatic species.Pollution observed in 1974 included large quanti-ties of trash and junk (including beer cans, tires,and even automobiles), pipe cement, and an un-known black liquid in lower Backlick Run.

Since the mid-1970s, the Citys water quality pro-tection efforts have included a vigorousstormwater detention program, the adoption of aChesapeake Bay Preservation Ordinance in 1992,the implementation of a number of pollution pre-vention programs, and the development of an in-novative pollution control and urban stormwatermanagement retrofit program that has attractednational attention.

WATERSHEDS AND WATERRESOURCES

II.2

To set the stage for discussing modern water and

environmental resources protection efforts, itmakes sense to think in terms of watershedsrather than neighborhoods or political jurisdictions.Watersheds provide a natural division for resourcemanagement. Water pollution is dynamic, as riv-ers, streams, and groundwater transport pollutionfrom higher to lower elevations. As a result, wa-ter pollution becomes a shared problem and

ultimately, a shared responsibility. This fact high-lights the need for local, regional, and State coor-dination in the water quality planning process.

Alexandria is divided by three watersheds as de-fined by the Virginia Division of Soil and Water

Conservation. These are the Four Mile Run(#A12), the Cameron Run (#A13), and thePotomac River (#A14). In practical terms, FourMile Run drains the northern and eastern portionsof the City while Cameron Run drains the remain-der of the City except for areas of Old Town whichdrain directly to the Potomac River.

In addition to these larger streams, a myriad ofsmaller tributaries, some of which are still largelynatural and some of which have been significantlyaltered or undergrounded (piped), drain the Citys

landscape. Significant named tributaries includeHolmes Run, Backlick Run, Hooffs Run, TaylorRun, Timber Branch, Strawberry Run, and LuckyRun. Figure II.2 provides a map of the majorwatersheds and the location of creeks, branches,runs, and licks of Alexandria. Figure II.3 providesa map of Alexandrias watersheds from a regionalperspective.

For the purpose of analysis, this section is dividedinto relatively distinct components that togetherprovide an overall picture of the health of

Alexandrias watersheds. These include surfacewater quality, streambank erosion and streambuffers, Potomac River shoreline, wetlands, andgroundwater resources. In addition, this sectionincludes a discussion of the source and protec-tion of Alexandrias potable water supply.

Surface Water Quality

Among the most important indicators of the healthof a watershed is the quality of the water runningin local rivers and streams. Protecting the qualityof surface water is a major challenge for many

urban jurisdictions, including Alexandria. In addi-tion to dumping and other overtly illegal acts, pol-lution that collects on parking lots, roof tops, anddriveways, is often flushed directly to local streamsduring storm events. This is particularly true for

Alexandria, which was largely built-out beforeregulations affecting water quality becameadopted.


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FIGURE II.2Major Streams and Watersheds of Alexandria

Water quality standards are set under the federalClean Water Act (CWA), which is administeredby the Virginia Department of Environmental Qual-ity (VADEQ). All State waters are expected to bemaintained to support recreational use and thepropagation and growth of all aquatic life reason-ably expected to inhabit them. These are known

as the CWA swimmable and fishable goals. Theparameters used to measure these goals includedissolved oxygen content (DO), pH (alkalinity/acidity), maximum temperature, and fecal coliformbacteria count. Standards for these parametersare different for the tidal portions of Cameron Runand Four Mile Run (classified as Class II, tidalCoastal zone) and the remaining non-tidal tribu-

taries within the City (Class III, non-tidal Coastaland Piedmont zones). The only difference be-tween the two standards is that there is no estab-lished maximum temperature for Class II waters.

Fecal coliform levels are the most important froma human health standpoint. These indicator or-

ganisms, while not necessarily harmful in them-selves, are found in the intestinal tracts of warm-blooded animals, including humans, and there-fore can be indicative of fecal contamination andthe possible presence of pathogenic organisms.

Temperature, DO, and pH are the primary indica-tors of the health of the aquatic ecosystem. The

Ho

lmesRun

Backlic

kRun

Strawb

err

y

Run

CameronRun

Ta

ylor

Ru

n

TimberBranch

Hooff

s

Run

GreatHunting Creek

Po

tomac

Ri

ver

FourMileRun

Lake Barcroft

Turke

ycock

Run

Lake Cook

LuckyRu

n

Potomac River

A14

Four Mile Run/

Potomac River

A12

Cameron Run

A13

LEGEND

City Boundary

Major Watershed Boundary

Tributary Stream

Source: NVPDC. 1998.


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FIGURE II.5Sources of Fecal Coliform Contamination

in Four Mile Run

FIGURE II.4Fecal Coliform Trends in Cameron Run

0

500

1000

1500

2000

2500

19991998199719961995199419931992

805

559

2225

958

Desirable Maximum Instantaneous

Count (1000 cells/100ml)

Desirable Maximum GeometricMean (200 cells/100ml)

916

CAMERON RUN

ANNUAL GEOMETRIC MEAN

1992 TO 1999

950

671784

Other

12%

Canine

9%

Deer

10%

Raccoon

15% Human

17%

Waterfowl

37%

Inconclusive5%

Unusable9%

FalsePositives10%

Unknown25%

AcceptableMatches51%

Success of Matching

Bacteria With Potential

Sources (N=539)Distribution of Acceptable

Matches by Animal Group

(N=278)

Source: Simmons, et al., Septamber, 2000, Estimating Nonpoint FecalColiform Sources in Northern Virginias Four Mile Run Watershed.


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of warm water can cause thermal shock to manyaquatic species. Because these pulses are typi-cally short in duration, they are often not detectedduring monitoring. However, their impacts canbe devastating. Volunteer monitoring in Four MileRun has measured temperatures to rise as quickly

as 10F in an hour. Thermal shock can occur

with changes of 3 or 4in an hour.

Fecal coliform contamination continues to be aproblem for Four Mile Run and Cameron Run.

Alexandrias situation is by no means unique, asmost of Northern Virginias streams show elevatedlevels of these contaminants. At the CameronRun monitoring site, 57% of samples tested inthe unhealthful range (greater than 1,000 fc/100ml) for fecal coliform in 1999. Monitoring inthe Four Mile Run reveals similarly high levels of

fecal coliform contamination. Results of testingat Columbia Pike for the period from 1995 to 1999show that 21% of samples tested above the un-healthful level. Fecal contamination was slightlyworse at the George Washington Parkway moni-toring site where 28% of samples tested in theunhealthful range.

Long term monitoring results (see Figure II.4)show that levels are consistently elevated but fluc-tuate according to year and rainfall.

The sources of bacteria contamination have beendebated for a number of years. In 2000, a jointeffort between the Northern Virginia RegionalCommission and Virginia Tech shed light on thesubject by applying DNA analysis to bacteriastrains in Four Mile Run. The study revealed thatwaterfowl account for over a third of all bacteriamatches (37%), followed by humans (17%), rac-coon (15%), and canine (9%) (see Figure II.5).Equally of significance, the study found that thebacteria appears to regrow, through cloning, withinstorm drains and stream sediments thereforeperpetuating the problem. Having such informa-

tion is critical to eventually managing the prob-lem of bacteria in Alexandrias streams.

The Fairfax County Health Department also testsfor nitrate nitrogen, total phosphorus, and a vari-ety of heavy metals. The log average for CameronRun for arsenic, barium, cadmium, chromium,lead, mercury, selenium, and silver is consistently

below EPA contamination standards. The aver-age nitrate nitrogen level in Cameron Run for 1996was 0.8 mg/l, which is well below the maximumunhealthful level of 10 mg/l. However, levels havebeen rising, albeit slowly, from 0.6 mg/l in 1992.

Average total phosphorus levels have remained

stable at an acceptable 0.1 mg/l.

The 1998 Virginia Water Quality Assessment,which reports monitoring by VADEQ on a water-shed-wide basis, found that all samples in thatyear for Cameron Run were good for total phos-phorus. In the Four Mile Run, 94% of sampleswere found to be in the good range, 4% in the fairrange, and 2% in the severe range. Four MileRun is the only watershed in the middle PotomacRiver basin to report severe conditions. VADEQsfindings for nitrogen were less positive. Cameron

Run had 36% of samples in the good range and64% in the fair range. Four Mile Run reported24% of samples in the fair range, 61% in the poorrange, and 15% in the severe range, which is thesecond worse in the entire Virginia portion of thePotomac River watershed. Overall, both water-sheds are considered high priorities by the Com-monwealth for nonpoint source pollution.

Current water quality monitoring efforts, becausethey only occur at certain intervals and test for afew specific parameters, often leave undetectedacute toxic pulses that occur when an uninformedor uncaring individual dumps a toxic substancedown a stormdrain or directly into a stream. It isthese incidences of dumping that most often re-sult in fish kills and can devastate an otherwisehealthy ecosystem in moments. Actual examplesreported to the City Fire Marshall include drain-ing oil from an automobile directly into astormdrain and washing paint brushes, cans, andsolvent containers into a stormdrain culvert.

In Alexandria, responding to these incidences isa cooperative effort among the VADEQ, the Alex-

andria Department of Transportation and Environ-mental Services, and the Fire Department, de-pending on the nature of the problem. Accordingto VADEQ records for the Alexandria area (includ-ing portions of Fairfax County in the Alexandriazip code), there were four reported incidences in1996, 29 reported incidences in 1995, 33 reportedincidences in 1994, 14 reported incidences in


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1993, 14 reported incidences in 1992, seven re-ported incidences in 1991, and nine reported in-cidences in 1990. Many incidences likely are notreported and go unmitigated.

The most common contaminants include fuel oil,

gasoline, foam, diesel fuel, and antifreeze. Othertoxic substances found in City streams includepaint, trichloroethylene, car wash waste, salt run-off from roads, transmission fluid, floor cleaner,chlorinated pool water, freon, soap, creosote,mineral oil, mineral spirits, hydrazine, and vari-ous unidentifiable white, black, green, and yellowsubstances. Few waterbodies have been un-touched by these incidences since most of themare connected to streets, parking lots, and yardsthrough culverts and stormdrains.

Despite the obvious challenges, watershed-widemanagement efforts to date have resulted incleaner water, and Alexandria, through its publiceducation, street sweeping, and urban retrofit pro-grams, as well as upgrades to the AlexandriaWastewater Treatment Facility, has contributedsignificantly to this success. Trend data collectedby the VADEQ indicates that the Potomac Rivercontinues to improve in many areas, although insome areas past gains are being slowly erodedas a result of population pressures. Nitrogen lev-els in the Potomac River are fair but improving.Dissolved oxygen levels are good and improv-ing. However, chlorophyll levels (high levels ofwhich indicate excessive algae growth as a re-sult of an oversaturation of nutrients) are goodbut degrading. The VADEQ also measureswhether the Potomac River is meeting certainaquatic habitat objectives including available light,the health of phytoplankton communities (themore the better), suspended solids (the fewer thebetter), and phosphorus. The upper PotomacRiver (including Alexandrias waterfront), fails thetest for available light and suspended solids andis borderline for phytoplankton communities and

phosphorus.

As noted earlier, Virginia has embarked on anextensive and vigorous effort to reduce nutrientsin the Potomac River and the Chesapeake Bayknown as the Tributary Strategy program. Fu-ture planned improvements in Alexandria that willhelp Virginia meet and maintain its Tributary Strat-

egy goal (a 40% reduction in nutrients from a 1985baseline) include upgrades to the AlexandriaWastewater Treatment Facility and continued ret-rofit of urban areas with water quality manage-ment facilities.

Stream Bank Erosion andStream Buffers

The physical integrity of a stream including itsbanks and areas buffering the stream has a di-rect impact on stream habitat and water quality.Degraded physical integrity of a stream is typi-cally a symptom of too much water volume for astreams capacity. As impervious surface areaincreases, stormwater tends to enter local streamsall at once, rather than infiltrate slowly into thesoil where it enters a stream at a much reduced

volume and rate. Urban streams seek to find newequilibrium by expanding their capacity, resultingin undercutting and widening of banks, deepen-ing of channels, and gullying. The impact on waterquality and habitat can be devastating. Soil sedi-ments, which also contain nutrients, are washeddownstream where they eventually settle andsmother aquatic communities. In addition, aquatichabitats are destroyed because water levels instreams fluctuate from torrential, during stormevents, to a trickle during periods of extendeddryness.

While the impacts on water and habitat qualitycan be devastating, flooding as a result of astreams inability to handle increased stormwatervolume and velocity can seriously impact thewelfare of local residents and businesses.

Most of Alexandrias major waterways have beenhardened and/or channelized over time to stabi-lize eroding stream banks and to increasestormwater volume carrying capacity. The larg-est of these projects is the lower Four Mile Runflood control channel from Shirley Highway to its

confluence with the Potomac River. By the middlepart of the twentieth century, the cumulative im-pacts of development in the Four Mile Run wa-tershed resulted in frequent flash flooding of the

Arlandria section of Alexandria and Arlington. In1974, Congress authorized the U.S. Army Corpsof Engineers to design and construct a flood con-trol channel for Four Mile Run that would contain


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TABLE II.1Options for Addressing Impaired Streams

Stream is Already Channelized Most of Alexandrias channelized streams are designed to control aspecific flood volume. In the case of Four Mile Run, Alexandria is legally bound to clear of any vegeta-

tion and silt that may reduce the channels capacity. Likewise, allowing extensive growth of vegetationor silt build-up in stormwater conveyance channels, in many cases, will result in flooding and possiblyproperty and environmental damage. The vegetation that typically grows on the banks or silts of thesechannels are fast growing, hardy, low lying edge-of-the-forest species. Due to their low lying nature andvigorous growth, these types of vegetation are precisely what needs to be avoided in these areas.

An option, in these cases, includes the purposeful planting of high-canopy native vegetation far enoughback from the channel to protect its physical integrity. The high-canopy will provide shade and somehabitat. Native, moisture-loving vegetation that may be appropriate include sycamore, beech, etc. Ar-eas immediately around the channel may be maintained as a native wildflower meadow, low-lying nativevegetation, or as a grassy area (if a manicured look is desired).

A Natural Stream is Experiencing Erosion Problem If the stream channel is in natural condition, butexperiencing moderate or sever erosion problems, the following options may be considered.

Bioengineering.Bioengineering refers to a host of techniques that utilize fast growing, hardy plantsand other natural materials to stabilize a streambank. When performed correctly, and in the rightcontext, bioengineering can increase habitat value, stabilize stream banks, and add nutrient uptakeby riparian buffer vegetation. Bioengineering is usually accompanied with the regrading or gradingback of the affected banks. Otherwise, vegetation may be lost or damaged through additionalundercutting. Therefore, bioengineering is only feasible in situations where erosive volumes aremoderate, where stream banks can be regraded, and where the maintenance of bioengineeringonce in place is possible. It is very important that sites are properly screened to ensure the maxi-mum probability of success. Stream reaches that have been field identified as potential bioengi-neering demonstration sites include a small tributary traversing Four Mile Run Park, lower Straw-berry Branch along Fort Williams Drive, and a small tributary of Holmes Run located in Dora KellyPark. The locations of these sites are provided in Figure II.6.

Stream By-Pass. An innovative means of protecting a stream from erosion, or as an alternative tohardening, is to construct a floodwater bypass system. While normal flows stay within the naturalstream bed, floodwaters above a set level are directed to an adjacent, underground storm sewerwhich can relay the extra volume downstream. The benefit of this alternative is that the stream canbe maintained in a natural state and that future damage can be avoided. This technique may notwork well in areas that have already experienced severe erosion problems or where limited space isavailable. A further consideration is that an area adjacent to the stream must be disturbed in orderfor the construction of the diversion, which may require easements or limited removal of trees.

Let the Stream Adjust. In some cases, where erosion is not severe and the floodplain adjacent tothe stream is wide enough, it is best to let the stream adjust naturally to its new carrying capacity.Eventually, the new channel will widen or deepen, or form meanders, to handle increased stormwa-ter flows.

Window Dressing. There are times when stream hardening is the only solution to an erosionproblem. Even so, stream channelization projects can often be designed in a manner that is moreaesthetically pleasing. While not always fiscally feasible, areas with the most visibility can be con-structed in this manner. A vegetation management plan that promotes the use of native vegetationthat does not interfere with flood capacity may also be a part of the channelization effort.


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An important outgrowth of the flooding problemsof the 1960s and 1970s, and as a requirement offederal funding of the Four Mile Run flood controlproject, was the implementation of on-sitestormwater detention requirements for develop-ment and redevelopment in the City. Instead of

allowing stormwater to enter the local stream net-work all at once, the City requires that it be de-tained and released slowly to mimic the landsability to hold large volumes of water over time.Since the 1970s, Alexandria has invested heavilyin its system of stormwater conveyance and de-tention. As of 1992, there were over 135stormwater control structures located within Al-exandria. As a result, the need for futurechannelization and hardening projects has beenreduced, although by no means eliminated, andthe opportunity to stabilize remaining natural

stream segments by other means has been in-creased.

While stream hardening will continue to be nec-essary under some circumstances, depending onthe specific problem, a number of additional habi-tat-friendly stabilization options now exist. Howto address remaining natural, but physically de-graded streams should be viewed in the contextof the options presented in Table II.1.

Figure II.6 shows major natural and man-madestream channels in Alexandria. Areas identifiedby the Department of Transportation and Envi-ronmental Services as experiencing moderate tosevere streambank erosion and areas identifiedas possible bioengineering demonstration sitesare also shown.

A natural, undisturbed, mature vegetated forestbuffer is among the most effective means of pro-tecting water quality and aquatic habitats from theimpacts of land use development. Not only doesa vegetative buffer protect streams from runoffand activities from adjacent land uses, the tree

canopy also serves to cool and moderate streamtemperatures. The Citys Chesapeake Bay Pres-ervation Ordinance requires the preservation ofa 100-foot buffer area landward and adjacent toall Resource Protection Area components andtributary streams during development.

Many of Alexandrias tributaries lack stream-sidevegetation, and specifically, mature tree canopy.In some highly urbanized areas of the City, orwhere streams have been hardened for flood con-trol purposes, establishment of an area of stream-side vegetation may not be practical or feasible.

To compensate, the City has and must continueto be proactive in identifying denuded buffer ar-eas and habitat that can be restored.

Potomac River Shoreline

Alexandrias Potomac River shoreline stretchesfor 7.8 miles from Hunting Creek on the south toFour Mile Run on the north. As with the Cityssmaller streams, the physical integrity of thePotomac River shoreline is important to minimizeerosion and to protect wildlife habitats. Most of

the Potomac River shoreline from DaingerfieldIsland south is hardened with various combina-tions of rip rap and concrete, and wood and steelbulkheads. In some areas, hardening has allowedpublic access to the Potomac River, while in oth-ers it has been necessary to prevent harmful ero-sion. Overall, approximately 58% of the shore-line is artificially stabilized, of which 75% is riprap, 20% is bulkhead, and 5% is channel gabion.Daingerfield Island, which is maintained by theNational Park Service, represents the largest natu-ral area along the Alexandria waterfront.

The vast majority of the bulkheads and hardenedareas along the Potomac range from fair to goodcondition although pockets of debilitated struc-tures dot the shoreline. As development has con-tinued along the Alexandria waterfront, remain-ing less stable bulkheads are slowly disappear-ing. Figure II.7 provides an inventory of PotomacRiver shoreline stabilization efforts, based on anOctober, 1998 field survey, and highlights the con-dition of bulkhead and stabilization structures.

While the Daingerfield Island shoreline has been

left in a largely natural condition, other pockets ofnatural shoreline can be found along the Alex-andria waterfront. Cobbles, washed from

Alexandrias colonial streets and natural landforms, and banks with high clay content have pre-vented the development of significant areas ofshoreline erosion.


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FIGURE II.7Inventory and Condition of Potomac River

Shoreline Stabilization Structures

KEY

(P) Poor Condition

(F) Fair Condition(G) Good Condition

Bulkheads

Rip Rap

Source: October, 1998 NVPDC Field Survey.

(G) City Marina: wooden piers, concrete bulkheads.

(G) Old Dominion Boat Club: steel bulkheads.

(G) Foot of King Street: steel bulkheads.

(F) ODBC Parking Lot: poured concrete/concrete slab bulkheads.

(G/F) Waterfront Park: wood and steel bulkheads with concrete backing. Mild slumping in areas.

(G) Foot of Prince Street: rip rap backed by concrete sidewalk.(Fminus) Dandy Docking/Parking Facility: poured concrete/concrete slabs with cobble beach.

Parking area flows directly to Potomac.

(G) Alexandria Marine/Alexandria Yacht: wood and steel bulkheads.

(G/F) Point Lumley Park: steel bulkheads (good shape), poured concrete bulkheads showsome signs of undercutting and erosion.

(G) Robinson Terminal: high steel bulkheads.

(G) Roberdeau Park: steel bulkheads.

(G) Ship Yard Park: new pressure treated wood bulkheads.

(P) Old rip rap, old wooded bulkheads, old poured concrete, remains of boat ramp.

Some active undercutting of poured concrete.

(P) Old Town Yacht Basin: extensive decaying pilings, rotted wooden bulkheads exposing combination of poured concrete/concrete block, and brick. Fenced.

(F) Pommander Walk Park: semi-natural mud flat, extensive cobbles and off-shore rip rap keep erosion at a minimum.

(G) Fords Landing: new rip rap with steel and wood base, poured concrete walkways.

(F) Old chunks of concrete and rotting pilings, some newer rip rap.Cobbles stabilize beach area.

(G/P) Jones Point: high poured concrete bulkhead. Northern end in poor shape.

(P) Wilson Bridge: poured concrete bulkhead failing in areas, active erosion.

(G/P) Jones Point: rip rap, some localized moderate erosion at high tide.

(F) Lighthouse

(G/P) Jones Point: rip rap, some localized moderate erosion at high tide.

(G) Founders Park: rip rap backed by grassed/vegetated buffer and gravel walkways.

(G) Robinson Terminal: concrete bulkheads with wooden pilings and reinforced concrete docks.

(G) Oronoco Bay Park: rip rap backed by grassed/vegetated buffer and gravel walkways. Areas planted with wetland plant species.

(G/F) Alexandria Rowing Facility: rip rap and concrete bulkheads. Areas ofextensive native wetland vegetation.

(G) Rowing Facility to PEPCO Facility: rip rap backed by grassed buffer. Walkway abuts water/wooden bulkheads in some areas.

(G/F) PEPCO Facility: treed bluffs in a largely natural state. Some rip rap poured in vulnerable areas. Several reinforced wastewater

outfalls present.

(G/F) Daingerfield Island: largely natural with some rip rap.

(G) Washington Sailing Marina.


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Wetlands

Wetlands serve as habitat for a wide range ofplants and animals and are important as a meansof buffering and protecting local streams from theadverse impacts of development. Wetlands are

especially important areas for nutrient uptake byvegetation and for pollutants and other materialsto be filtered and settled out before reaching lo-cal streams and rivers. While Alexandria has formost of its history treated wetlands as areas tobe reclaimed (lower King Street from Lee Streeteast was once open water) there still remains sig-nificant wetland areas within the City.

The City has delineated and mapped its wetlandsin accordance with the federal Manual for Delin-eating Jurisdictional Wetlands. Most of the Citys

wetlands are located adjacent to the PotomacRiver, Four Mile Run, Cameron Run, and othermajor tributaries. City wetlands are generally clas-sified as palustrine (tidal wetlands along thePotomac River and the lower Four Mile Run andCameron Run), riverine (adjacent to free flowingtributaries), and lacustrine (open water, usually apond or lake). Map II.1 shows the Citys delin-eated wetlands.

Wetlands must be identified for individual devel-opment sites according to all applicable federal,State, and City wetlands regulations, including theCitys Chesapeake Bay Preservation Ordinance.Wetlands are protected under section 404 of thefederal Clean Water Act, which is administeredby the U.S. Army Corps of Engineers.

While remaining healthy wetlands should gener-ally remain undisturbed, it is possible to use wet-lands as open space and for education purposes.

An example of this is Huntley Meadows Park inFairfax County. A specially engineered raisedboardwalk through part of the park allows resi-dents to see first hand how a wetland functions,

resulting in a greater appreciation for these re-sources. Smaller-scale, local examples includewetland areas of Dora Kelly Nature Park, the Wild-life Sanctuary in Four Mile Run Park and the pri-vately owned Winkler Botanical Preserve.

In addition, opportunities to restore degradedwetlands or to create new wetlands should con-

tinue to be explored. If wetlands are impacted bydevelopment or projects, to the extent possiblethe impact or loss should be mitigated throughwetland creation or enhancement, improvementsto riparian areas, or through the use of creativeBest Management Practices to treat stormwater.

Groundwater

During its earlier years, the City relied heavily ongroundwater for its supply of potable water - as isevidenced by the multitude of wells, most of whichare now closed, that dot the older parts of theCity. While no longer relying on groundwater fordrinking water, groundwater protection is still im-portant. Many streams are fed by groundwater,especially during periods of extended dryness.Groundwater is extremely dynamic, and ground-

water contamination can spread rapidly. Oncecontamination has occurred, mitigation is veryexpensive and time consuming.

The groundwater aquifer of the City consists pri-marily of the unconsolidated sediments of theCoastal Plain. Baring the introduction of man-made contaminants, natural groundwater char-acteristics are fairly stable over time because theyare largely dictated by the chemical and struc-tural characteristics of the local aquifer. An analy-sis of the Citys aquifer performed in 1985 indi-cates that groundwater in Alexandria is generallysuitable for a variety of domestic, commercial, andindustrial purposes.

Well yield potential in the City ranges from low inthe northwestern portions of the City (less than100 gal./min.), to moderate in the central portionsof the City (100 to 200 gal./min.), to moderatelyhigh in the eastern portions of the City (200 to800 gal./min.). Groundwater quality is generallyexcellent in the eastern portions of the City andgood in the remainder of the City. The exceptionis an area of naturally occurring poor groundwa-

ter quality located in portions of the City west of I-395. Groundwater in this area may locally con-tain high concentrations of sodium chloride, iron,and total dissolved solids. Groundwater withinthe City is generally soft (hardness < 60 mg/l) andtotal dissolved solids (ranging from 91 mg/l to 174mg/l) are far below the recommended maximumof 500 mg/l.


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Limiting factors associated with groundwater thatshould be considered during the development andredevelopment processes include the presenceof two groundwater recharge areas. While mostCoastal Plain areas serve as local recharge ar-eas, regional recharge areas have been identi-

fied as the area near Cameron Station north to I-395 and west to the City limits and the larger NorthRidge area (including Beverly Hills and ParkFairfax). These areas are depicted in Figure V.1.Since these areas are already developed, themost appropriate means of protecting these re-charge areas is to minimize impervious surfacearea during the redevelopment process to allowfor infiltration of rainwater into the soil.

Large areas of eastern and central Alexandriahave also been identified by the U.S. Geological

Survey as having high potential for groundwatercontamination due to a combination of natural andman-made factors. The remaining portions of theCity are considered to have moderate potentialfor groundwater contamination. Protecting theseareas from contamination requires the preventionor mitigation of common sources of groundwaterpollution. While these sources of pollution arediscussed in further detail in Section III, they mayinclude leaking underground storage tanks, failedseptic fields, leaking sanitary sewer lines, andabandoned industrial/landfill sites. Of thesesources, the VADEQ has sited underground stor-age tanks as the greatest threat to groundwatersupplies.

Potable Water Supply and WaterSupply Protection

Alexandria relies on surface water withdrawalsoutside its boundaries for its municipal water sup-ply. While there are currently a small number ofoperational wells within the City that are main-tained for industrial purposes, all existing devel-opment is connected to the municipal water sys-

tem. All new development is required to be con-nected to the municipal water system.

The Citys supplier/distributor of potable water isthe Virginia-American Water Company (VAWC).Virginia-American, in turn, purchases treatedwater from the Fairfax County Water Authority(FCWA). The FCWA maintains two water intakes,

one on the Potomac River in Loudoun County(Corbalis intake) and one on the Occoquan Res-ervoir. The VAWC is set up to conduct chlorineand ammonia treatment as needed, and fromtime-to-time, may post-treat water from the FCWAif chlorine levels drop appreciably.

Alexandrias water supply is among the best pro-tected in the Commonwealth. By cooperativeagreement under the Occoquan Basin NonpointPollution Management Program (established in1978), the entire Occoquan Reservoir watershedhas been subject to Best Management Practicesto control nonpoint source pollution since the early1980s. Alexandria is an active participant in thisprogram through the Virginia-American WaterCompany and City staff. In addition, large areasof the Occoquan Reservoir watershed have been

downzoned to protect the watershed from largeareas of impervious surfaces. Water quality moni-toring for a wide array of parameters is conductedon a routine basis by the Occoquan WatershedMonitoring Lab to ensure that the water remainssafe as a drinking water supply.

The Citys potable water supply is more than ad-equate to meet future needs. However, the Cityalso recognizes the importance of water conser-vation as a way to protect the environment and toprotect the regions natural resources in the longterm. The City currently uses 15.38 million gal-lons per day (MGD). The Virginia-American Wa-ter Company has conducted an extensive analy-sis of anticipated water needs for the City withina 15-year projection. The VAWC projects that bythe year 2010, average use will rise to 17 MGDand peak use will rise to 25.4 MGD. The approxi-mate allotment from the Fairfax County Water

Authority is 25 MGD, which is sufficient to meetexpected growth demands.

The VAWCs program for maintaining its drinkingwater lines includes regular analysis of water,

comprehensive plan studies, and annual system-wide flushing. The VAWC does not have a for-mal water conservation program, and instead,relies on public service announcements callingfor reduced usage (i.e., watering lawns or wash-ing cars) during exceedingly long dry spells. Ac-cording to the VAWC, the public is usually respon-sive, and there has been no need for additionalconservation efforts.


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THE LAND AND LAND FORMS

II.3

Land is the foundation of most human activities.Local geology and soil features, and the result-

ant topography, more than any other features willoften dictate what type of activity is appropriateor feasible for a particular site. For instance, im-proper development on sensitive soils or steepslopes can easily result in soil erosion which con-tributes to downstream nutrient problems and cre-ates long-term difficulties for structures built uponthese soils.

The following is a description of the topography,geology, and soils of the City and the potentialconstraints that these features represent. Map

II.2 illustrates the extent of these constraints, in-cluding marine clay soils and steep slopes.

Topography

The City of Alexandria has an exceptionally di-verse topography. Elevations range from almostsea level along the Potomac River shoreline andlower Four Mile Run and Cameron Run to 280feet above sea level near Alexandria Hospital.Physiographically, the area of Alexandria can bedescribed as a plain that has been dissected bynumerous streams which have cut narrow, shal-low valleys into the landscape. While most of theterrain is gently rolling, numerous tributaries havecut steeper valleys. In general, Four Mile Runand Cameron Run form two well defined valleyswhich frame the City while a series of hills dividethe spine. Most of the steepest slopes in the Cityare associated with the smaller tributaries thathave cut through the central plain. In general,the further west into the City, the higher and morerolling the terrain.

Slopes greater than 15% require particular con-

sideration during the development or redevelop-ment processes due to the risk of erosion andslump. While most of the City is considered roll-ing terrain, there are significant areas whereslopes are greater than 15%, particularly adja-cent to dissecting stream channels.

Geology and Soils

While topography is a manifestation of underly-ing characteristics, the characteristics of the ge-ology and soil also have an important impact ondevelopment.

The City is situated almost entirely within theCoastal Plain physiographic province of Virginia.The Coastal Plain consists of intermixed layersof sands, pebbles, mud, and silts that were de-posited as a result of erosion from areas to thewest when water levels were higher than they arenow. Geologically speaking, the City is fairlysimple. The dominant geologic feature is thePotomac Formation, deposited in a deltaic-typeenvironment (much like the present day Missis-sippi Delta) during the Cretaceous Period (144 to

65 million years ago, or mya). The Potomac For-mation occupies the western two-thirds of the Cityand is characterized by light-gray to pinkish andgreenish-gray sand and pebbles. The remainingeastern third of the City is underlain by the ShirleyFormation, which was deposited much later, dur-ing the middle Pleistocene Epoch (1.8 to 0.1 mya).The Shirley formation consists of light to dark gray,bluish gray, and brown sand, gravel, silt, clay, andpeat and is the result of surficial deposits of thePotomac River and relict baymouth barriers andbay-floor plains. A small outcrop of the BaconsCastle Formation (deposited during the upperPliocene Epoch, 5.8 to 1.8 mya) is found in theBeverly Hills area and is characterized by gray,yellowish-orange, and reddish brown sand, gravel,silt and clay. Centered around T.C. Williams H.S.and the Northern Virginia Community College aretwo outcrops of the Yorktown Formation whichconsists of bluish-gray, and brownish yellow fineto course grained sands with interbedded sandyand silty blue-gray clays. These beds are com-monly very shelly. The oldest rocks in the City,which are part of the Occoquan Formation, occurnear where Holmes Run enters the City. The

Occoquan Formation, which consists of light gray,medium to coarse grained granites, is actually partof the Piedmont Province and was formed over560 million years ago.

Differences in erosion rates between underlyingrock formations have shaped modern drainagepatterns and the contours of the landscape.


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Soils serve as the lifeblood of the ecology as wellas the most basic of building material for road-ways, embankments, and building foundations.

As a result, they are very important to take into

consideration during the development process.Not surprisingly, because Alexandria has longbeen an urban rather than an agricultural center,the last soil survey was conducted in 1915 by theU.S. Department of Agriculture, Bureau of Soils.Because most soils in the City have been devel-oped and redeveloped since that time, thereforepermanently altering soil structure, the study, en-titled Soil Survey of Fairfax and Alexandria Coun-ties, Virginiais useful only to demonstrate gen-eral soil characteristics. For most development

purposes, an onsite soil test should be conductedto determine exact soil properties.

Because the underlaying parent materials arerelatively flat, soils in Alexandria generally changein accordance with elevation and relation tostreams and rivers. The soils of Alexandria in-clude, from lowest to highest elevation:

Ochlockonee (Oi), Huntington Loam (H), KeyportSilt Loam (K); Susquehanna Loam (So);Sassafrass Gravelly Loam (Sf); and LeonardtownSilt Loam (L) and Loam (Lo).

Figure II.8 provides a map of major soil

groups while Table II.2 provides a briefdescription of each of these soils. Theonly soils of genuine concern in the Cityare those which contain marine clay (orshrink-swell) soils, those which are lo-cated on steep slopes, and those whichexperience prolonged wetness or inun-dation due to flooding or low depth togroundwater. While areas experienc-ing flooding or prolonged wetnessshould not be developed, areas withmarine clays may be built upon (and to

a large extent, have been built upon) ifproper precautions are taken. Risksassociated with marine clay include ex-cessive shrinking and swelling, whichcan crack building foundations, andland slides and slumping during peri-ods of prolonged wetness. Marine claylayers that are only a few inches to afew feet thick may be overcome if build-ing footings are extended to the nextlayer. Thicker occurrences have beendocumented and may require addi-tional precautions or preclude sometypes of development.

It is difficult to predict marine clay presence bysoil type since most soils in Alexandria have ar-eas of marine clay. However, Susquehanna loam,Sassafrass gravelly loam, and Keyport are par-ticularly prone to areas of marine clay. Map II.2shows areas which are underlain by marine clays.

WILDLIFE AND NATURALHABITATS

II.4

A healthy and diverse habitat is the end goal ofan effective watershed management plan. A pe-riodic inventory of Alexandrias existing naturalhabitats is useful, if not necessary, to bench markthe success of water quality management efforts

Soi l Nam e G en er al O ccur rence T op og raph y Dra in ag eDevelopmentLimitations

Ochlocknee Occupies a few strips alongsmall streams. In Alexandria,

associated with Cameron Run,Holmes Run, and Backlick Run.

Relatively flat, typically 4to 6 feet above normal

flood stage.

Poorly drainedand subject to

occasionaloverflows andwetness.

Unsuitable for mostdevelopment.

HuntingtonLoam

Occupies narrow strips alongthe Potomac. In Alexandria,

limited to Jones Point andDaingerfield Island.

Relatively flat. Typically 4to 10 feet above sea

level.

Good drainage.Subject to

periodic wetnessfrom flooding.

Unsuitable for most, butnot all, development.

Keyport SiltLoam[Matapeake/Mattapex]

Occurs on the low, smooth

terraces along the PotomacRiver. All of Old Town and

much of the surrounding area isunderlain by this soil.

Gently undulating to level,

and in places slightdepressions occur. A few

of the slopes are rathersteep, and the margins

are often distinguished bybluffs. Typically 20 to 30feet above sea level.

Drainage is fairly

well establishedexcept for small

depressions.

Few unfavorable features,

some areas mayexperience high water

table, therefore limitingthe use of basements.

Clay material of thesubstratum is well suitedfor the manufacture of

brick and tile.

SusquehannaLoam

Occurs upland of Ochlockneeand occupies large areas ofAlexandria including

Eisenhower Valley and theDuke Street corridor.

Gently rolling toundulating, although thereare occasional steep

slopes.

Fair. Few unfavorable features.

SassafrasGravely Loam

Occurs in narrow strips alongthe slopes of the plateau likeareas of Leonardtown loam and

silt loam, in West Alexandria isthe largest area.

Steep to gently sloping Drainage is good. Few unfavorable features.Some areas of marineclay and steep slopes.

Contains large areas ofheavy, waxy clay.

LeonardtownSilt Loam[Beltsville SiltLoam]

Occupies the highest areas of

the City from Shuters Hillextending northwest.

Surface is gently

undulating to nearly level,with occasionaldepressions.

Surface drainageis generally poor.

Internal drainageis also slow in

areas, causingperiodic wetnessafter rain.

Few unfavorable features.

TABLE II.2Alexandrias Soils and Suitability forDevelopment


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FIGURE II.8Generalized Alexandria Soils Map

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Major Road

City Boundary

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KEY TO SOILS

Source: Digitized by NVPDC from U.S. Department of Agriculture. Soil Survey of Fairfax andAlexandria Counties, Virginia. 1915.

over time. Much of Alexandrias natural landscapehas experienced radical change since the firstEuropean settlers took root in the area during theearly 18th century. Even before Alexandria be-gan to experience its most recent surge in growthafter World War II, areas outside of Alexandriasurban core were subject to clearing for agricul-tural and industrial purposes. During the Civil War,the area between Alexandria and Fairfax wasdescribed as totally denuded by trees as for-ests were cut down to build defenses and to pro-vide fuel for heat.

Despite the odds, regrowth of vegetation, scat-tered parcels of open and undeveloped land, util-ity rights-of-ways, and stream valleys, in combi-nation with suitable forms of development, have

resulted in a limited, yet remarkably resilient wild-life habitat known to ecologists as typical subur-ban. While many species have taken up resi-dence in lawn trees or wooded back yards, thebulk of the Citys wildlife habitat can be foundalong natural areas of the Potomac River and theCitys stream valley parks.

Wildlife habitat in Alexandria is diverse, but canbe roughly divided into tidal and nontidal. Nontidalhabitats include free flowing streams and forestsof Alexandrias uplands while tidal habitats includethe estuarine portions of Four Mile Run and Hunt-ing Creek as well as their associated wetlandsand marshes. Differences in vegetation that oc-cupies these two areas should be consideredwhen restoring or reforesting habitat areas.


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Records maintained by the Virginia Departmentof Conservation and Recreation, Division of Natu-ral Heritage (DNH), reveal the extent to whichmany species still call Alexandrias stream val-leys home. In the Cameron Run watershed arethirty-seven different species of fish, seventeen

types of frogs, salamanders, and toads, five spe-cies of turtle, and over twenty species and sub-species of snake (including the poisonous cop-perhead). In the Four Mile Run watershed areover fifty-seven different species of fish, eighteentypes of frogs, salamanders, and toads, five spe-cies of

Documents

Alexandria Water Quality Master Plan