On the Prince William Water website, you can find an information page on data centers. All their statements while true are incomplete and somewhat misleading in some instances. This is part of a series discussing more fully some of the issues they address. In the blog post below the bold face print is what Prince William Water posted the rest is my discussion.
Do data centers reduce available ground water for
residents on private wells?
The drinking water provided by Prince William Water to
serve new development in the western service area comes from public sources in
the Potomac River and Lake Manassas, not from groundwater wells. Hence, public
water supply does not affect ground water supply for private wells.
True, the public water supply is drawn from the Potomac
River for the western service area and the Occoquan Reservoir and Lake Manassas
for the eastern service area. However, groundwater can be impacted by data
centers (and development in general) in two ways. Directly and indirectly.
Directly. The water for data centers (cooling and landscape
and miscellaneous indoor and outdoor use) comes from either public water supply
(either potable water or reused water) or even potentially groundwater. There
are no restrictions or permitting necessary for a data center to use a well for
water supply in Prince William County. Watering lawns and landscaping at these large facilitiesthroughout the warm months uses a lot of water at these massive facilities also
uses lots of water.
Data Centers are cooled using either air conditioning
(electricity) or evaporative cooling (water). Evaporative cooling is more
efficient and effective. Data centers that are water cooled use large amounts
of water for cooling systems (even in closed loop systems), which ensure that
the heat produced by these massive facilities is controlled.
There are no restrictions or permitting necessary for
groundwater use in Prince William County. The Virginia
Water Withdrawal Reporting Regulation only
requires the annual reporting of direct surface water and groundwater
withdrawals each year of any entity withdrawing more than 300,000 gallons per
month.
Reports made to DEQ for Prince William County indicate that
40,000,000-70,000,000 gallons of groundwater a year was being used for a pump
and treatment system and 30,000,000-35,000,000 gallons of groundwater a year
was being used by an industrial user (who I believe to be Amazon based on
a conversation with DEQ). There are an unusual number of large capacity wells
(100-750 gallons per minute) in the Manassas area that do not report to
DEQ. They could be pumping less than the
reportable amount of water, or their owners simply unaware of their actual flow
rate or the need to report use. Another way around the reporting requirements
is to have several wells, none of which exceed the limit.
Ground water flow and storage is often viewed as static
reservoirs that serve as the savings account for surface water flow. Through
the hyporheic zone groundwater feeds streams between rain storms, but
groundwater is dynamic and continually changing in response to human and climate
stress [Alley
et al., 2002; Gleeson
et al., 2010]. Changes in precipitation patterns, the amount of
precipitation, the , and the changes in land use impacts available groundwater and
surface water.
Land use changes that increase impervious cover, add more
suburban lawns, roadways, buildings, pavement and eliminate woodlands does two
things. It reduces the open area for rain and snow to seep into the ground and
percolate into the water table and groundwater and the impervious surfaces
cause stormwater velocity to increase preventing water from having enough time
to percolate into the earth, increasing storm flooding and preventing recharge
of groundwater from occurring. Land use changes also potentially increase
the use of groundwater by adding more homes and businesses that utilize
groundwater.
Very slowly, changes in land use change the ecology of the
watershed and can reduce the water supply over time. As groundwater continues
to be used levels fall, perennial steams that feed the rivers become
intermittent during dry periods like this past summer and the summer of 2023. This is what appears to be happening in the Bull Run Mountain Conservancy area where
for the second summer in a row perennial streams stopped flowing in
the summer.
Changing land use and the changing climate that are bringing
new patterns of rain and drought and are
impacting the Occoquan Reservoir. As Prince William Water points out: “Once used by data centers in western
Prince William County, the wastewater is treated at the Upper Occoquan Service
Authority Water Reclamation Plant and released as reclaimed water to the
Occoquan Reservoir. In this water cycle, water used from the Potomac is
reclaimed and released into the Occoquan Reservoir, adding volume.” Higher
wastewater effluent while the changing climate and land use reduce river flow can introduce higher relative concentrations of minerals and salts, pharmaceutical, personal care and
cleaning chemicals into the drinking water supply, potentially requiring
additional treatment lines at great expense for all customers of the Griffith
plant.
As Prince William Water points out: “Additional purchased (water) capacity must be timed in coordination with required infrastructure improvements for both Prince William Water and Fairfax Water, since purchasing additional capacity and delivering more drinking water may require infrastructure improvements.” Infrastructure improvements like additional treatment lines, additional reservoirs to assure continued availability of water are very expensive. In the billions of dollar range. This is reflected in the price of water.
We need more information before we damage or destroy our fragile Bull
Run and Occoquan Watersheds. We are paving over the watershed with roads, data
centers, parking lots houses and electrical infrastructure reducing the groundwater
recharge, reducing our stream flow and increasing the water demand. Although
hidden in the subsurface, groundwater is the most important freshwater
component in the hydrological cycle. Groundwater exists below all land with
varying distance to the surface, but only in 20-30% of the land area is groundwater
close to the land surface to feed surface streams and provide ecological
services.
Groundwater releases water to streams sustaining the base
flow of streams and rivers (Hare et al., 2021). Groundwater is the
primary source of springs and many wetlands
(Bertrand et al., 2011; Havril et al., 2018;
Gleeson et al., 2020a). Finally, the groundwater saturated
subsurface, the hyporheic, makes up the largest continental biome
contributing to the health and purity of our water resource. The small
changes that the Bull Run Conservancy has reported in the springs, seeps and
streams is telling us that our watershed is changing, and not in a good way.
It appears that even with just the current level of development, the depth to groundwater is increasing enough to disconnect some streams from the groundwater during summer months. These are the first small signs that the watershed is beginning to die- streams become intermittent and eventually become ephemeral- flowing only during rainstorms. These streams flow into the Bull Run and the Occoquan River that provide the portion of our eastern service area drinking water supply that is not from recycled wastewater. Of course as Prince William Water points out, increasing numbers of data centers will increase the amount of wastewater available, but that may not be all good. During rainless periods the fraction of treated wastewater could exceed the amount of natural water very soon.
Prince William County is beginning to see changes in the Bull Run watershed. The groundwater is becoming disconnected from Little Bull Run and Catlett’s Creek in the area of the headwaters of those streams. Once the hydrology and ecological biome is destroyed by development, it cannot be easily restored, if at all. Protecting the Occoquan Reservoir requires protecting all the water resources in a region because all water in the watershed is connected.
Kumari Yadav S (2023) Land Cover Change and Its
Impact on Groundwater Resources: Findings and Recommendations. Groundwater -
New Advances and Challenges. IntechOpen. Available at: http://dx.doi.org/10.5772/intechopen.110311.
Anke Uhl, Hans Jürgen Hahn, Anne Jäger, Teresa
Luftensteiner, Tobias Siemensmeyer, Petra Döll, Markus Noack, Klaus Schwenk,
Sven Berkhoff, Markus Weiler, Clemens Karwautz, Christian Griebler, Making
waves: Pulling the plug—Climate change effects will turn gaining into losing
streams with detrimental effects on groundwater quality,
Water Research, Volume 220, 2022, 118649, ISSN 0043-1354,
https://doi.org/10.1016/j.watres.2022.118649
Julia Zill, Christian Siebert, Tino Rödiger, Axel Schmidt,
Benjamin S. Gilfedder, Sven Frei, Michael Schubert, Markus Weitere, Ulf
Mallast, A way to determine groundwater contributions to large river
systems: The Elbe River during drought conditions, Journal of Hydrology:
Regional Studies, Volume 50, 2023, 101595, ISSN 2214-5818,
https://doi.org/10.1016/j.ejrh.2023.101595.
(https://www.sciencedirect.com/science/article/pii/S2214581823002823)
No comments:
Post a Comment