Changes to the comprehensive plan, the increased rate of
construction, changing climate and land use conspire to undermine the
resiliency of our water system in Prince William County and the greater
Washington DC metropolitan area.
Global Water Bankruptcy: A Warning
In January 2026, the United Nations University's Institute
for Water, Environment and Health (UNU-INWEH) released its "Global Water
Bankruptcy" report. The report warns that certain regions have moved past
temporary water stress and entered irreversible water bankruptcy, meaning a
permanent inability to return to former water levels the exact opposite to
water resiliency. Humanity is depleting its water savings—groundwater, lakes,
ecosystems, and glaciers—but can no longer rely solely on annual precipitation
to supply its communities. Are we in the Washington Metropolitan Area headed
for the same fate?
First What is a Resilient Water Supply
In general, a resilient water supply is the
ability of a water system—including its infrastructure, management, and natural
source water—to withstand, adapt to, and quickly recover from shocks and
stresses. Sustainability a related concept focuses on meeting current
needs without compromising future generations, "resilience"
specifically targets the capability to handle disruptions like the
recent big freeze, droughts and intense storms.
Core Dimensions of Water Resilience
The key pillars of water Resilience:
- Robustness: The
physical strength of the system to resist damage. This is the "hardened"
infrastructure like pipes and pumps that resist soil shifts and weather
related breaks and treatment plants that can operate during extreme
weather conditions and floods.
- Redundancy: Having
"spare capacity" or back-up systems. For example, if a primary
river source is contaminated, a resilient system can instantly pivot to
stored reservoir water or secondary interconnections with a neighboring
utility. The Potomac River supplies most of the drinking water supply in
this region. If there is a spill, Fairfax Water can turn to the Occoquan
Reservoir, but a long duration need, like a severe drought might not be
able to be met.
- Adaptability: The
capacity of the organization to adjust operations as conditions change.
This involves using real-time data to manage demand or modifying treatment
processes to handle new contaminants.
- Rapidity: The
speed at which a system returns to normal service after a failure, often
supported by mutual aid agreements and emergency power sources.
A resilient system is designed to navigate both sudden
"shocks" and long-term "stresses":
- Sudden
Shocks: Hurricanes, earthquakes, cyberattacks, chemical spills, intense
cold snaps, and the sudden main breaks which are associated with sudden
cold snaps. The resilience of our neighbors at WSSC and DC Water during
the recent big freeze was lacking.
- Chronic
Stresses: Prolonged droughts, aging infrastructure, rapid
population or demand growth, and shifting climate patterns.
The Role of Natural Infrastructure
Modern definitions of resilience increasingly include Ecological
Resilience. This refers to the ability of watersheds, wetlands, and forests
to naturally filter pollutants and slow down stormwater runoff, protecting the
"built" infrastructure from being overwhelmed during extreme weather
which is increasing.
Prince William County maintains a modestly resilient water system through a
combination of diverse water sourcing, regional interconnections, and
significant infrastructure investments managed primarily by Prince William
Water. However, about 10% of the population are not customer of PW Water.
1. Diversified Water Sources
The county utilizes four distinct sources to ensure a steady
supply:
- Potomac
River: Primary source for the western part of the county treated
by Fairfax Water at their Corbalis Plant.
- Occoquan
Reservoir: This is a sole source for the eastern part of the
county. PW Water is completing a project to build a second connector to
the Griffith Plant.
- Lake Manassas: Supplements the western part of the county with water treated by City of Manassas Water and could provide supply for a period of time if the connector to the Corbalis water treatment plant was disrupted.
- Groundwater Wells: Six public wells
serve the Bull Run Mountain and Evergreen system. This is a single source
community dependent on groundwater wells in a small geographic location.
Source Water
resilience
Let’s go back and look at what has been happening in Prince
William County to impact the availability of water and water resilience.
In Prince William County the conversion of open and forested lands into
developed surfaces poses several direct threats to water resilience and sustainability,
including increased pollutant runoff and degraded groundwater recharge.
Primary Threats from Land Use Change
- Increasing
Impervious Surface prevents rainwater from soaking into the ground. And
increasing stormwater runoff and flash flooding .
- Increased
Pollutant Loading without natural filtering sediment, nitrogen,
phosphorus, and heavy metals flow directly into rivers and the Occoquan.
- Reducing
groundwater recharge and the availability of groundwater.
Fairfax Water recommended that the Prince William Board of
Supervisors strengthen riparian buffer protections by establishing an
Environmental Resource Overlay District, requiring a 50-foot buffer of woodland
for non-Resource Protection Area streams. For industrial development, they
advised mandating 200-foot buffers, retaining existing forested areas instead
of replanting, and utilizing permanent protective easements. Fairfax Water also
called for prohibiting the discharge of high-salinity "blowdown"
water into the system.
In December 2022, the Prince William Board of County
Supervisors approved the "Pathway to 2040" Comprehensive Plan, which resulted in the Removal of
Sewer and Density Restrictions, allowing for more widespread development
infrastructure and higher density. New Land Use Designations effectively
"upzones" sensitive areas.
Though they Occoquan Reservoir Protection Area (ORPA),
but recent BOCS decisions have upzoned several areas of open land justifying
the decision with the new existence of marvelously magical building techniques.
Industrial and Data Center Expansion including the
Digital Gateway and a new industrial area along Route 28 near the Fauquier
County line, further converting open land to intensive use.
Emerging Water Supply Strains
New research from the Interstate Commission on the Potomac
River Basin (ICPRB) highlights that changing weather patterns and increased
water demand from data centers are straining the region’s water supply.
The 2025 Washington Metropolitan Area Water Supply
Study - Demand and Resource Availability Forecast for the Year 2050
finds that while the region will generally have ample water, the risk of
shortages is increasing—from about 1 percent in 2030 to 5 percent in 2050 even accounting
for all planned water storage increases
in the period. Loss of groundwater is not factored into their model. ICPRB
forecasts a 17% increase in water use by 2050, from 465 million gallons per day
(MGD) to about 538 MGD.
Climate
Change and Water Demand
Increasing water demand and predicted changes in temperature
and precipitation—characterized as “hot drought”—may threaten river flow.
Rising temperatures decrease river flows through higher evaporation, while
increased precipitation could raise flows. The interplay between these factors,
land use change reducing groundwater recharge combined with higher demand, puts
the source water system at higher risk.
Water
Supply Sources and Risks
While most regions have multiple water sources, the Potomac
River is the sole drinking water source for Washington D.C. and Arlington
County. Fairfax Water uses the Potomac River and the Occoquan Reservoir. Upstream
reservoirs (Jennings Randolph and Little Seneca) can supplement Potomac River
flow. However, the study found that, in extreme droughts, upstream reservoirs
could run dry as early as 2030 in four out of nine scenarios, suggesting a need
for additional storage.
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