The Rural Crescent, the Occoquan and the Water Supply

The Board of Supervisors of Prince William County have allocated $60,000 to engage a study to examine if the goals desired from the creation of the Rural Area of the county have been met through the implementation and management of the Rural Crescent. In addition, the study is to identify other rural preservation tools that would allow the elimination of the Rural Crescent restrictions on development density. This is a direct result of a motion by Supervisor Martin Nohe at the regular March meeting of the Prince William County Board of Supervisors.

The Rural Crescent was created in 1998 and originally intended as an urban growth boundary for the county designed to preserve the agricultural heritage and force redevelopment along the Route 1 corridor rather than development in the remaining rural areas. This was to be accomplished by limiting development to one home per 10 acres with no access to public sewers. The Rural Crescent has been chipped away at for years, but still contains 80,000-acres; however, active farming in Prince William continues to decrease.  To adequately judge the utility of the Rural Crescent the study must consider its impact on water resources and water ecology. While the Rural Crescent may have been the wrong policy to preserve our agricultural heritage, it has been a success at preserving water resources, protecting our groundwater and supporting the ecosystem of our estuary. In addition, continued redevelopment of areas with preexisting infrastructure will allow Prince William County to improve storm water management in those areas and score nutrient points for the EPA mandated TMDL as well as revitalize older areas of the county and support of sustainable development. The Rural Crescent is about water, specifically groundwater.

The Rural Crescent in Prince William aligns roughly with the Culpeper groundwater basin, one of the more important watersheds in Virginia and essential to the health of the Occoquan Reservoir which in turn is an essential element in the drinking water supply of Fairfax Water - Prince William Service Authority, PWSA, obtains most of the drinking water they distribute in the county wholesale from Fairfax Water. Besides purchased water from Fairfax Water, PWSA operates the Evergreen water wells that draw water directly from the Culpeper Basin and thousands of home owners have private wells that also draw from the aquifer. The Virginia-American Water Company also distributes water purchased from Fairfax Water. Any changes in land use have the potential to negatively impact groundwater, the watershed and the Occoquan Reservoir and should be considered in the study of “other preservation tools.”  

The Rural Crescent is located within the northeast quadrant and eastern quadrant of the Culpeper basin and consists of an interbedded sequence of sedimentary and basaltic that is highly fractured and overlain by a thin cover of overburden. While ground water flows generally speaking west to east, the fractures within the rock run predominately north south. Contaminants can enter the groundwater at these fractures and zigzag through the aquifer, but these fractures also serve as recharge areas. Groundwater is typically protected against contamination from the surface by the soils and rock layers covering the aquifer, but there is inadequate overburden in much of the Rural Crescent. Once contaminated, groundwater is very difficult to clean and in a fractured rock system there is limited if any natural attenuation and the aquifer could be polluted beyond our ability to remediate.

Generally, groundwater in the Culpeper Basin is replenished each year through precipitation. Groundwater recharge through precipitation requires adequate area for infiltration of rainwater, control of sheet flow created by roads and paved areas, as well as protecting the most geologically favorable infiltration points. Precipitation and snow melt flows over the ground as surface runoff. Not all runoff flows into rivers, much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes the saturated subsurface rock of the aquifer, which store huge amounts of freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into rivers, creeks, and ponds as base flow for the rivers, and some ground water finds openings in the land surface and emerges as fresh water springs.

According to the U.S. Environmental Protection Agency, impervious cover levels of 10% can significantly impact watershed health increasing stormwater runoff. When runoff volume increases, runoff velocity increases, and peak storm flows causes flooding and erosion.  Increased stormwater velocity increase soil erosion, increases nutrient contamination and reduces water infiltration into groundwater. The groundwater is essential as the base flow to the streams and rivers that feed the Occoquan Reservoir during the dry months. The groundwater stored in the watershed can supply adequate water to maintain river flow during droughts. Maintaining open areas provides areas of groundwater recharge and controls runoff. Decisions about the fate and management of the Rural Crescent will impact groundwater quantity and quality and in turn will impact water flows to the Occoquan Reservoir during dry periods.  Flow to the Occoquan Reservoir is essential in managing the drinking water withdrawals from the Potomac River.  The Interstate Commission on the Potomac River Basin, ICPRB, manages the Potomac River drinking water allocations for the entire region by “suggesting” the quantity that Fairfax Water draw from the Occoquan and Potomac daily.  Prince William County’s decision on the fate of the Rural Crescent could impact drinking water supplies in Fairfax, Maryland, and DC as well as our own county.

 

The “rural preservation tools” to be investigated as part of the study are sustainable community concepts, high density communities utilizing the strategies of Low Impact Development, LID, which include dedicated open space. While high density communities built adjacent to dedicated open space of cute community farms as is being done in Loudoun might preserve our agricultural heritage, it will not guarantee the preservation of our ecosystem and water. When development disturbs more than 10% of the natural land by covering surfaces with roads, driveways, walkways, patios, and homes the natural hydrology of the land is disturbed, irreparably disturbed. These developments while much better than traditional developments still disturb more than half the land area by significantly increasing building density. 

The lack of overburden limits natural protection to the aquifer, but has allowed easy infiltration. The sedimentary rocks of the Rural Crescent are productive aquifers and feed not only the groundwater wells that provide drinking water to Evergreen and other communities, but also feeds the tributaries to Bull Run assuring the base flow to the rivers and streams that feed the Occoquan. Our freshwater resources need to be managed as a whole. Development that will impair the recharge of the aquifer can result in impacts to the entire region, including the decrease in water level and aquifer storage, reductions in stream base flow and lake levels, loss of wetland and riparian ecosystems, saltwater intrusion and changes in groundwater quality. Our future and our children’s future is our water. We can’t allow it to be destroyed  in paving roads and building houses for short term gain.

The Rural Crescent an Essential Part of Our Green Infrastructure

At the regular March meeting of the Prince William County Board of Supervisors while considering requests for exceptions to the comprehensive plan, Supervisor Martin Nohe supported by the other county Supervisors seemed to feel that it was time to reconsider some of the planning and development decisions that had been made in the past and asked for staff to produce an analysis of the usefulness of the Rural Crescent in achieving those goals. The request was made by Supervisor Nohe to Prince William County staff and noted in the minutes.

The Rural Crescent was created in 1998 and has been chipped away at with exception requests every year. Higher density development means money to developers and landowners. There is much passion when money is on the table. The Rural Crescent in Prince William County was originally intended as an urban growth boundary for the county designed to preserve our agricultural heritage and force redevelopment along the Route 1 corridor rather than Greenfield development in the remaining rural areas. Maintaining the emphasis on redevelopment of areas with preexisting infrastructure would allow Prince William County to improve storm water management, achieve nutrient and sediment reductions for the EPA mandated TMDL, revitalize older areas of the county and preserve the Greenfields. The Rural Crescent may have started with different intentions; but today the Rural Crescent is about water, groundwater and ecosystem preservation.

Supervisor Nohe’s interest in transforming the 80,000-acre rural crescent where development has generally limited to one home per 10 acres with no access to public sewer is of great concern. Even though I believe that Supervisor Nohe is interested in moving towards sustainable community concepts, high density communities utilizing the strategies of Low Impact Development, LID, which include dedicated open space will not guarantee the preservation of our ecosystem and water. When development disturbs more than 10% of the natural land by covering surfaces with roads, driveways, walkways, patios, and homes the natural hydrology of the land is disturbed, irreparably disturbed. These developments while much better than traditional developments still disturb more than half the land area by significantly increasing allowed building density.

 While it has been demonstrated that LID strategies can reduce the impact of development, there is no demonstrated strategy of how communities can control and maintain natural storm water features and preserve and maintain the safety and ecology of preserved open space. There are no regional groundwater studies, regional ecosystem pans and no budgets for maintaining the open space.  Access control and prevention of improper use (underage drinking, drug use and sale,  other illicit activities, dirt bike racing) addressing deer population management and hunting adjacent to high density homes, litter and trash removal, maintenance of natural landscapes and supervision all cost money and time. No legal structures exist that guarantee open spaces will not be developed in the future to defray maintenance costs.  Why the Rural Crescent was formed is less important than understanding that the Rural Crescent provides a significant portion of our green infrastructure to our community.  

Green infrastructure connects the still intact habitat areas through a network of corridors that provide for wildlife movement and trails as well as pathways for pollinators. Maintaining intact, connected natural landscapes is essential for basic ecosystem and watershed preservation to ensure that there will always be clean air and water in Northern Virginia. Maintaining a tree canopy and controlling runoff to prevent stream bank erosion and water quality impairments and maintaining adequate water flows through groundwater and surface recharge are vital to ensuring safe water supplies, water recreation and the ecological integrity of the region. The Northern VirginiaRegional Commission (NVRC) has developed a Conservation Corridor PlanningProject which is a regional effort to identify essential green infrastructure and help area governments to avoid the mistakes of the past and maintain the few remaining green corridors along the rivers and reservoirs in Fairfax and integrate green infrastructure planning into the future development planning of Prince William and Loudoun counties.  

According to NVRC there are three priority regional conservation corridors in Prince William County.  Bull Run Mountain and Catoctin Mountain corridor is a north-south corridor connecting the foothills of the Blue Ridge Mountains in Northern Virginia.  The corridor provides significant intact habitat for Northern Virginia wildlife.  North of Leesburg, the corridor is the karst terrain of Loudoun underlain by limestone, and highly susceptible to pollution that provides a significant ground water recharge.

Karst aquifers are highly vulnerable to contamination. This vulnerability results from: sinkholes, widened flow paths, and rapid velocities of ground water and contaminants. Contaminants can be transmitted quickly from entry in a sinkhole to wells and springs in the vicinity. Sinkhole creation, sinkhole flooding, and groundwater contamination are the major hazards associated with karst terrain, and unlike other natural hazards they are chronic in nature. South of Route 50 the Bull Run Mountain ridge is the location of a significant area of recharge for the groundwater that ultimately maintains and feeds Bull Run and the Occoquan River. This area is part of a fractured rock system with limited overburden and no natural attenuation. A polluted plume could be carried for miles without dilution.

The second priority conservation area is begins at the Bull Run Mountains and heads east across Route 15 to Manassas covering the land between Route 50 and 29 to the confluence of the Occoquan River with Belmont Bay. This corridor is rich in water and environmental resources that ultimately deliver drinking water to over one million Northern Virginia residents. The Occoquan Reservoir, one of the country’s first water reclamation facilities where sewage treatment water is returned to provide water recreation. The western portion of the area is part of the Culpeper Basin Important Birding Area and the Culpeper Basin Groundwater Aquifer. Preventing water contamination and ensuring adequate groundwater recharge are vital to ensuring safe water supplies, recreation opportunities and the ecological integrity of the region.

The third priority conservation area is the Potomac Gorge and Quantico Corridor, the greenbelt that connects Prince William National Forest Park with Manassas Battlefield. This area includes large tracks of undeveloped private land. The western portion of the Rural Crescent was not identified by NVRC as a high priority conservation area because they failed to consider the importance of the groundwater aquifer. The Culpeper basin is part of a much larger PiedmontGeologic Province and has only begun to be studied thanks to the carefulgroundwater measurements taken by Loudoun County as excessive development ofthe western part of the county began to impact water supplies.  Groundwater quantity and quality in our region impacts not only groundwater wells, but stream flow and recharge to the surface water. In short all the drinking water in Prince William County. Groundwater recharges at various rates from precipitation and other sources of infiltration. The recharge is not spread evenly across the land. Pave over the land, change surface flow and infiltration and groundwater recharge are reduced.

Important regional waterways, such as Goose Creek, Bull Run, the Potomac River and Occoquan Reservoir thrive because they are shaded by trees and vegetation that filter stormwater, prevent erosion, and facilitate ground water recharge and moderate temperatures. Green infrastructure maintenance ensures the forested buffers are maintained and enhanced over time, protecting public health and water quality. Maintaining and enhancing forested buffers near Northern Virginia’s waterways requires focus on how to maintain and protect these ecological resources. The EPA has identified nitrogen, phosphorus and sediment as the three primary pollutants that must be reduced to restore the health of the Chesapeake Bay and its tributaries. They have mandated to Virginia and the other Chesapeake Bay Watershed states and Washington DC an approximate 25% reduction in these pollutants. A wide range of approaches can address these impairments, including reducing runoff and restoring stream banks and buffer areas. Adding more development in the Rural Crescent will not reduce the current level of sediment and nutrient pollution, and will not assure our water resources and ecology. 

Board Vote Stops Mid-County Project in the Prince William Rural Crescent

On Tuesday, March 20th, 2012 at their regular meeting the Prince William County Board of Supervisors voted on the 2012 Annual Comprehensive Plan Amendments that were submitted to the planning office this past January. There were six changes in zoning requested, only two of the requests that appeared to fit within the long term goals of the comprehensive plan had the staff recommendation for approval: the New Dominion Square and Bradley Square both in the Coles District. These were requests to change from community employment center to building townhouses and included the redevelopment of the speedway property. However, the Mid-County Park and Estate Homes request for a rezoning in the Rural Crescent (also in the Coles District) was stopped by the motion and presentation of Supervisor Nohe and the support of the majority of the BOCS. This project would have effectively removed this property from the Rural Crescent to increase density from 33 homes to 104 single-family homes connected to the public sewer system, but would have also created 195 acres of public open space. The project had received considerable publicity and raised passions on both sides as evidenced by the citizens comments earlier in the meeting.

The plan for long range land use in Prince William County is designed to develop employment centers in the community, revitalize the Route 1 corridor, preserve the rural areas and areas of environmental sensitivity including lands regulated under the Chesapeake Bay Protection Act and preserve our existing neighborhoods. In short the comprehensive plan is really a forward looking document for sustainable development that needs to continue to evolve over time. Prince William has learned from Fairfax, Alexandria and Arlington to carefully plan the growth of our community. The Supervisors seemed to feel that it was time to reconsider some of the planning and development decisions that had been made in the past and asked for additional study as the best way to achieve employment, transportation and open space goals of the county, asking for analysis of the usefulness of the Rural Crescent in achieving those goals and the future of the last contiguous large (864 acre) parcel in the development area of the western half of the county.

In the next several years the county will have to find ways to meet the ever tightening requirements under the Virginia Watershed Implementation Plan for the mandated Chesapeake Bay TMDL and we need to make sure that there will be adequate drinking water for the county. The first half of sustainable development is the redevelopment of the Brownfields along the Route 1 corridor rather than Greenfield development in rural areas where there is no existing infrastructure as highlighted by Supervisor Nohe’s presentations. Redevelopment along Route 1 would help Prince William County to reduce storm water damage by instituting storm water management in locations where storm water management is inadequate (and score nutrient reduction points under the Watershed Implementation Plan) as well as revitalize these older areas of the county. This redevelopment would take place without significantly increasing pavement and impervious surfaces. The second portion of sustainable development is to ensure adequate water for our county now and in the future. Preserving the open land in the Rural Crescent is essential to sustainable development of Prince William County. According to the EPA, in order to maintain the natural hydrology the impervious cover of a region must remain below 10%.

The Rural Crescent in Prince William County aligns roughly with the Mesozoic basin aquifer of the Culpeper groundwater basin, one of the more important watersheds in Virginia. The rocks of the Culpeper basin are highly fractured and overlain by a thin cover of overburden. These sedimentary rocks are productive aquifers and feed not only the groundwater wells that provide drinking water to Manassas and other communities, but also feeds the tributaries to Bull Run and the Potomac. The fractured rock system that is so rich in water is also our weakness; there is no natural attenuation in a fractured system so that the groundwater as a drinking water resource can be easily contaminated without any real ability to recover. Any malfunctioning septic system, underground fuel storage tank, improper disposal, improperly managed horse property or hobby farm or hazardous spill on any property within this area has the potential to impact the drinking water wells to the south, southeast or east. Development and improper use in this area introduces potential sources of contamination that could never (in our lifetimes) be remediated. In addition, ground cover, roads and pavement will impact recharge of the groundwater reducing the total amount of water available.

A small portion of Prince William County is located within the Coastal Plain and should serve as a warning to us of what happens if you do not protect your watershed and its recharge zone. The Coastal Plain of Virginia is composed mostly of unconsolidated geologic deposits and extends from the Atlantic coast to the “fall zone” a geological line that runs north-south through Fairfax, Fredericksburg, Richmond, and Petersburg along Route 95. There are two groundwater systems, an unconfined aquifer and a lower artesian aquifer both flow in the general direction of the topography slope towards the ocean. The fall zone was the area of recharge for the artesian aquifer, it was the geologic area where the earth folded and the lower mostly isolated artesian aquifer reached the surface and could be recharged with rainfall. By building Route 95 along the fall zone and developing the adjacent areas Virginia essentially paved over a significant portion of the recharge zone for the artesian groundwater aquifer-permanently reducing water supply while increasing water demand. In addition, poor storm water management in older developed areas has created a significant erosion and sediment problem in the Quantico Watershed, for example, where on-site stormwater capture and retention needs to be beefed up and repaired, and the streams need debris removal, channel restoration or enhancements, and riparian buffer restoration to stabilize the watershed.

The county may be moving towards reevaluating the zoning and land use decisions made at the end of the 20th century when the Rural Crescent was created. Owners of large tracks of land within the Rural Crescent feel (and rightly so) that limitations on development reduce land values. Many residents of the area spoke of the quality of life. The groundwater and watershed must always be considered because without water there is no property value. On any request to amend the Comprehensive Plan the Board of County Supervisors, BOCS, has the discretion to vote to initiate, initiate with a different study area, do not initiate or take no action. After citizen comments, staff presentations the BOCS discussed the proposals within the entire the land use plan and the county goals then voted to:

A. Do Not Initiate, the change of the Comprehensive Plan Amendment #PLN2012-00224 Stone Haven, but to initiate another Planning Study of the Stone Haven Project Area within the Brentsville Magisterial District with community outreach and input to determine the best use of this land and additional acreage owned by the same entity that could be the site of the needed new high school in the western end of the county. These 337 acres were proposed to convert from industrial to residential and the BOCS recalling community reaction to an industrial project that had been considered years ago felt that compatible use and community needs should be carefully considered before any decision is made for this property.
B. Do Not Initiate – Comprehensive Plan Amendment #PLN2012-00225, that would have allowed the building of 104 clustered homes within the Rural Crescent and have those homes hooked up to the sanitary sewer system for a development called Mid-County Park and Estate Homes and place the 77 acres that are resource protect area, RPA, under the Chesapeake Bay Protection Act) and an additional 62 acres and place them as permanent open space. Supervisor Martin Nohe argued to keep the boundaries of the Rural Crescent and the BOCS voted to support him. However, Supervisor Nohe further suggested that the BOCS examine the Rural Crescent policy the tools available to achieve the county environmental goals and maintain open space. The staff was charged with examining whether maintaining the Rural Crescent as is was in conformance with the open space goals of the county and what were the results of the policy after 14 years.
C. & D. Initiate. Comprehensive Plan Amendment #PLN2012-00226, New Dominion Square and Comprehensive Plan Amendment #PLN2012-00228, Bradley Square were voted to be combined and Initiated with an expanded study area both projects are located in the Coles Magisterial District. They were appropriately viewed as combined and related. The Dominion Square is a Brownfield redevelopment of the speedway and use of the Bradley Square is impacted by the use and redevelopment of the speedway property.
E. Withdrawn. Comprehensive Plan Amendment #PLN2012-00227, Wheeler Estate Property was withdrawn. This property is located within the Gainesville Magisterial District and had been recommended by staff to not be initiated. It would have represented a change from flexible employment to residential eliminating a significant number of jobs and adding commuter traffic on Route 66.
F. Initiate. Comprehensive Plan Amendment #PLN2012-00229, Bell Property which is adjacent to the Rural Crescent leaving the RPA area undeveloped and developing the SRR planned area for 55+ housing. The staff had recommended “Do Not Initiate,” but Supervisor Candland of the Gainesville Magisterial District where the property is located supported the development and argued persuasively to move forward and the majority of the BOCS voted with him.
G. Initiate. Comprehensive Plan Amendment #PLN2012-00301 the addition of Five Properties as County-Registered Historic Sites in the Cultural Resource Chapter of the Comprehensive Plan was voted to initiate without much discussion. The properties are located within the Gainesville and Brentsville Magisterial Districts.