Prince William County is engaged in revising the sections of the Comprehensive Plan that pertain to the Rural Crescent and the Infrastructure and Facilities Plan. The details of the revisions being considered have not been released, but I am lead to believe that allowing significantly increased housing densities and clustered development within what is now the Rural Crescent is being proposed.
Though clustered development appears to be a solution for the Board of Supervisors, planning commission members and the planning department faced with difficult choices about how much development to allow, where the development should go and who will make money from selling land for development, how and if it is implemented will impact the future of Prince William County. There are costs associated with clustered development. Homes clustered together cannot be on well and septic, and it is believed that the county is planning on bringing public water and sewer to these areas. The cost of providing public water to this area would be borne in part by the taxpayers and rate payers of Prince William County. In addition, adding homes adds students to our schools and the need for other services.
Even if connections to existing public water and sewer infrastructure are limited to cluster development along what is being called the transition area, such expansion may exceed the capacity of the current systems and require water and sewer infrastructure expansion. Clustered properties cannot rely on well and septic- they are simply too close together, clustered development will be connected to public water supplied by Prince William Service Authority. Public water in the areas adjacent to the Rural Crescent is supplied by a combination of groundwater wells and surface water supply that is purchased from Fairfax Water and Lake Manassas. There is a cost to purchase additional capacity from Fairfax Water and to utilize groundwater wells. In addition, piping and pumps will have to carry water from its source to any new development. This would force the County to find additional sources of water at greater incremental cost to all ratepayers and such sources may not even be available. In addition, water mains and sewage piping are costly not only to build, but also to maintain.
Residents within Rural Crescent rely on private wells for water and septic systems for wastewater disposal. Increased development can have an adverse impact on surrounding private wells and septic systems. Changing the use and cover of the land with buildings, driveways, roads, walkway and other impervious surfaces will change the hydrology of the site reducing ground water recharge in the surrounding area. Once the hydrology is destroyed by development, it cannot be restored. We need to study how any proposed land use change will impact water and groundwater sustainability for existing homes. The right of existing property owners to their water is primary and valuable and should not be compromised or impaired. Because there are natural fluctuations in groundwater levels it is easy to mask or ignore signs of the beginnings of destruction of the water resources that we depend on. Fluctuations in climate or rainfall and imperfect measurements and vantage points mask trends from clear view.
For development approved outside of existing public water and sewer infrastructure or the homes that currently exist there, there is a clear risk that future loss of water to that development may force new connections to public sewer and water at costs unbearable by that development or homeowners which are then put into the rate base and paid for by all ratepayers or taxpayers as has happened before. The real costs and risks to ratepayers and taxpayers must be determined and discussed before any plan is voted on and must be made public.
Private wells draw their water from groundwater. Geology, climate, weather, land use and many other factors determine the quality and quantity of the groundwater available. Within Prince William County Virginia there are four distinct geologic provinces: (1) the Blue Ridge, (2) the Culpeper Basin, (3) the Piedmont, and (4) the Coastal Plain. The U.S. Geological Survey divides the four geologic provinces of the county into seven hydrogeologic groups based on the presence and movement of the ground water calling them groups: A, B, B1, C, D, E and F. About 27 years ago the U.S. Geological Survey studied the groundwater systems within Prince William County.
The existing published hydrology and geology work by the U.S. Geological Survey dating to 1990 and earlier can no longer be relied on to develop a theoretical groundwater budget, as the area has developed, more of the land surface has been covered with buildings and roads that have impacted the groundwater recharge as well as the existing demand for groundwater has changed significantly. In addition, no recharge rate was ever calculated for the seven hydrogeologic groups.
To develop a theoretical groundwater budget it is essential to have the geologic specific recharge rate to determine an accurate estimate of sustainable groundwater availability and use, physical testing of the aquifer will need to be done. Fauquier County did not recognize the different recharge rates in their counties and ended up with groundwater supplies that were not sustainable. They found a key factor isn’t just how much water you’re pumping out of the ground, but rather where in the watershed and in what geologic province the water is being pumped from. Different locations within the County have different water availability. The County can’t change the underlying geology or control the rate or pattern of groundwater recharge. Instead we must yield to nature and plan our development without impairing water recharge.
In developing the groundwater budget the groundwater recharge rate for existing residences needs to be determined and the impact on the existing recharge rate of additional development needs to be estimated using real data points collected from monitoring wells as is being done in Fauquier County. Not only does the geology vary across our county with different water bearing and storage potential in the different hydrogeologic groups, but additional construction can impact how much of the precipitation recharges the groundwater. Before changing zoning or population density, it is necessary to have a high level of certainty that the availability, quality and sustainability of groundwater supplying the existing private wells would not be adversely impacted. If the county comprehensive plan and zoning amendments go through it is essential that the existing homeowners are assured that their groundwater supply will remain adequate to serve their wells into the future and not be depleted slowly over time.
This past winter the Virginia Legislature amended the enabling legislation for comprehensive planning (§§ 15.2-2223 and 15.2-2224 of the Code of Virginia ) to provide for the continued availability, quality and sustainability of groundwater and surface water resources on a County level as part of the Comprehensive Plan. While state law now requires that the County Comprehensive Plan address water availability, quality and sustainability as well as transportation needs directly, as practical matter new development creates a need for schools, hospitals, and electrical capacity with associated demands and impacts on water resources which must also be addressed.
Let’s make sure the future of the Rural Crescent is planed addressing all the risks.
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