Valley Commerce Center Will Use Too Much Groundwater

Dear Editor:

The proposed Valley Commerce Center applicant requests approval to pump 43,680 gallons of groundwater per day (gpd). During the April 15 Public Hearing on this project, the applicant’s team suggested that household use of water by the 39 by-right homes that might be built on this property would be higher than the proposed project groundwater pumping rate but presented no data to support this contention.  

During this same Public Hearing, it was stated that the County staff estimated that the likely water use by the 39 homes might total 13,650 gpd. This is equivalent to 350 gpd per home. The USEPA estimates that the average US family of 4 uses roughly 400 gpd which is very similar to the County staff estimate of usage. 

The pumping rate proposed by the applicant (43,680 gpd) is roughly 3 times the household use for 39 homes based on either of these per-home estimates (350 gpd staff, and 400 gpd USEPA).

It has been argued that the 39 homes would have large lawns and pools, and they would use much more water than average homes. Certainly, an individual homeowner may pump more than 400 gallons in one day, but not all of them will do so on any given day, and no one will do it 365 days per year, especially not during the several months of winter weather.  

The USEPA states that roughly 30% of the average 400 gpd usage per home is used exterior to the home for lawns, gardening, etc., but some homes use more for exterior uses, especially in arid parts of the country, where exterior needs may account for 60% of the total water usage.  

Based on this data, the resulting estimated average usage would therefore be 700 gpd per home in high usage areas. Applying this greater value to all 39 homes yields a total usage of 27,300 gpd.  The applicant’s proposed pumping rate is still more than 1.5 times this estimate, which is based on USEPA high-use, arid region data.  

Groundwater is a crucial resource for homes, agriculture, communities, and businesses in Western Loudoun County, and there is some evidence that groundwater levels locally and regionally may be declining.  

This means that even current groundwater usage may not be entirely sustainable in the long term, and there are many by-right homes, farms, and properly zoned businesses yet to be built in Western Loudoun which will all lead to increased groundwater usage. Therefore, eventual depletion of this crucial groundwater resource is virtually certain if steps are not taken to restrain its usage and/or enhance the recharge of Western Loudoun aquifer systems.  

The proposed project will withdraw much more groundwater each year than the 39 by-right homes on this site, and it will therefore accelerate groundwater depletion.

Why is this project’s excessive groundwater pumping rate being considered for approval, when the applicant has not incorporated various well-known techniques and technologies to minimize the need for potable water?  

Investing in active water harvesting and greywater reuse would reduce the need for groundwater pumping and reduce the likelihood that future offsite well replacement will ever be needed.  

The proposed project should have been designed to protect and conserve the groundwater resources that we all, including the applicant’s project, are dependent on.

I respectfully recommend that this application be denied.

Wayne B. Bergstrom
Ph.D, P.E. (emeritus)

Hillsboro