Klein Property Development -again

Late last year the Planning Commission recommended Stanley Martin’s most recent plan to transform the Kline farm property into a mix of townhomes, “pocket parks” and neighborhood-style commercial development. Developer Stanley Martin is seeking to rezone 55.42 acres of the 100-acre Kline farm property from A-1, or agricultural, to “planned mixed residential” and B-1, or general business. In addition, Stanley Martin is offering a 20-acre site for an elementary school instead of monetary proffers to the school division and the county’s parks and recreation department; and offering to sell the adjacent 25 acres as a possible site for the new baseball complex to Prince William County.

The Kline Farm property encompasses a bit more than 100 acres and is generally located south and southeast of the intersection of Prince William Parkway and Liberia Avenue, and north of Buckhall Road. The property is located in a transitional area of the county that is adjacent to the City of Manassas. Stanley Martin needs to expand their proffer an expanded well testing and monitoring to ensure the viability and health of their water supply to the existing nearby well owning homeowners. 

Residents within the abutting Hynson Knolls community, homeowners bordering Buckhall Road and homes along Lake Jackson Drive rely on private wells for water and septic systems for wastewater disposal. In a “Preliminary Hydrogeological Assessment-Klein Site” prepared by SES/TrueNorth they do a very preliminary look at whether the development of the site is likely to have an adverse impact on surrounding private wells and septic systems. The properties in the development will be connected to public water from supplied by Prince William Public Service Authority and with surface water as the source supply. So, there will be no increase in the use of groundwater in the immediate area.

In the Preliminary Hydrogeological Assessment the consultants only reviewed the existing well construction records dating back about 40 years when Hynson Knolls was first developed; existing published hydrology and geology work by the U.S. Geological Survey dating to 1990 and earlier; development of a theoretical groundwater budget and a fracture trace analysis of a 1978 photograph to determining the general flow of groundwater. No physical testing of the aquifer was performed and no recent data records were used.

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. You can review that report if you wish to see the entirety it is by Nelms and Brokman.

The consultants for Stanley Martin Homes identify the site as located within Hydrogeological Group E. The Klein Farm and vicinity are within a fractured bedrock aquifer in which groundwater availability and flow are controlled by fractures and joints within the rock. Hydrogeologic group E consists of metasedimentary, meta-volcanic, and other metamorphic rocks. Rocks within hydrogeologic group E tend to have poor to moderate water-bearing potential, and thin- to thick cover of overburden. Ground-water storage tends to be predominantly in the overburden which is typically relatively granular and porous. This is a water table aquifer separate from but hydraulically connected to the underlying bedrock aquifer. According to that USGS report by Nelms and Brockman, some of the poorest yielding wells are located in hydrogeologic group E. Because of the local geology care should be taken to ensure that the existing homes are not impacted by the development.

The fracture trace analysis performed by Stanley Martin Homes consultant found a predominant west-northwest to east-southeast regional fracture orientation; however, there was a notable but less prominent southwest to northeast regional fracture orientation also present. The groundwater flow in Prince William county is generally to the east-southeast, but there is considerable variation and surprises in the flow as documented by monitoring at several cleanup sites in the county and suggested by the fracture analysis.

In developing the theoretical groundwater budget the Stanley Martin Homes consultant assumed that the groundwater recharge rate for the site was equivalent to the average groundwater recharge for Prince William County. This is unlikely to be true. Not only does the geology vary across the county with different water bearing and storage potential in the different hydrogeologic groups, but Prince William county was over 52% open space when that recharge rate was developed, including the Prince William Forest Park, the Manassas Battlefield Park, Quantico, and the Rural Crescent.

It appears that the USGS studies that determined an “average recharge” was based on took place at Cedar Run and Broad Run, not characteristic of the hydrogeologic group underlying Klein property and adjacent area. It is unlikely that this site in its current state recharges at the “average recharge rate for the County” and the actual recharge rate of groundwater underlying adjacent to this site needs to be determined by testing.

Flux estimates of components of the hydrologic cycle can be made by creating a water budget in which the various components must balance. Such a water balance approach can be reasonably accurate when all of the terms in the budget can be calculated or reasonably estimated. This approach is appropriate for the scale of the entire Commonwealth, but not on a smaller scale like the Kline property and adjoining neighborhood. On a small local scale these estimates are not at all accurate or appropriate methods of determining groundwater adequacy or impact. Most accurate methods used to estimate recharge are highly dependent on local measurements in both space and time (Healy and Scanlon, 2010) this would need to be done for the Kline property and the surrounding neighborhoods to provide a high level of certainty that the availability, quality and sustainability of groundwater supplying the adjacent neighborhood wells would not be impacted .

This information is necessary to ensure that the neighbor’s water supply will not be impacted over time by the development. If the county comprehensive plan and zoning amendments go through it is essential that the neighbors be assured that their groundwater supply will be adequate to serve their wells into the future and not be depleted slowly over time.

Stanley Martin Homes has proffered to engage an environmental professional to perform a well yield and limited water quality test on any lawfully operating household water supply well for residential property located within 800 feet from the Kline property line to establish a baseline for the closest wells. Those well owners may request a re-evaluation of their well if a negative impact is suspected. If the impact is confirmed by the reevaluation then there is a procedure for the homeowner to request one of three forms of resolution within 30 days; repairing the well, drilling a new well or connecting the home to the public water system.

Sounds good; however, 800 feet which is effectively the first line of homes may not include enough area to ensure no impact. The U.S. EPA standard for determining impact is a much greater radius typically including 2.0 miles for class II a groundwater under the EPA’s Groundwater Protection Strategy. The scope to testing should be defined and include all primary and secondary contaminants regulated under the Safe Drinking Water Act. Finally, 30 days is too short to determine if a well can be repaired, identify and permit a new well site with the County Public Health Department , or determine if the home can be or should be connected to the public water supply. In addition, depletion of groundwater can be a very slow but real process and it might take years for homeowners to notice impact to their wells.

Stanley Martin should proffer to engage an environmental professional to perform a well yield and broad based water quality test including all primary and secondary contaminants and pesticides under the Safe Drinking Water Act on any lawfully operating household water supply well for residential property located within 2 miles from the Kline property line. In addition, a test well should be installed and added to the USGS monitoring network at an agreed upon location (and existing well could be converted to this purpose with the homeowner’s permission and guidance from the USGS and DEQ for adaptions). The homes should be retested after 5 years.