Ground Water Protection Council
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Key Message
Contaminated stormwater is a major source of ground
water and surface water degradation. Furthermore, landdevelopment
practices often create impervious surfaces that
increase stormwater runoff and inhibit ground water
recharge. A combination of approaches is needed to
improve runoff quality and maximize quality recharge to
ground water. These approaches include preventing the
contamination of stormwater, minimizing impervious
surfaces, segregating clean and contaminated stormwater,
and applying best management practices (BMPs) that
promote natural aquifer recharge and treat stormwater
sufficiently before it is discharged to ground water.
Construction of buildings, streets, and parking lots prevents rainfall from recharging soil
and ground water. It also increases the rate of runoff and contributes to water pollution. This picture is of a stormy day in Salt Lake
City, Utah.
Photo: Michael Kedzierski
USEPA and some states
have embraced low impact
development (LID), which
emphasizes reducing
impervious areas, disconnecting
impervious areas
from one another, and
treating stormwater so it
can infiltrate the ground
near the source. However,
even LID techniques, which
are designed to decrease
environmental impact of
development, sometimes
promote stormwater infiltration
without addressing
aquifer sensitivity, the
quality of the stormwater,
and stormwater’s potential
impact on ground water.
Ultimately, our challenge
will be to put these
approaches into practice at
the local level and to
ensure that they are
designed and maintained
properly so that ground
water is not degraded.
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why stormwater matters
to ground water...
In natural, undeveloped areas, a large
percentage of relatively uncontaminated
precipitation infiltrates the ground, thus
recharging the ground water; the remaining
runoff flows to nearby water bodies
or evaporates. Natural physical, chemical,
and biologic processes cleanse the water
as it moves through vegetation and soil
and into ground water. Development
alters natural systems as vegetation and
open spaces are replaced with new areas
of impervious surfaces such as roads,
parking lots, roofs, and turf, which greatly
reduce infiltration and thus ground
water recharge. Uncontrolled stormwater
runoff collects pollutants such as sediments,
pathogens, fertilizers/nutrients,
hydrocarbons, and metals, which ultimately
contaminate and degrade
surface and ground water.
An unknown number of stormwater drainage wells (UIC Class V) such as this can be
found throughout the country, discharging stormwater directly into ground water.
Photo: Oregon DEQ
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Recommended Actions
To USEPA:
- Establish better coordination among federal stormwater management,
ground water protection, underground injection control (UIC), and waterquality
monitoring programs so that programmatic overlaps can be elimnated
and opportunities for collaboration in protecting surface and ground
waters can be identified and initiated.
- Accord the protection and recharge of ground water and protection of surface
water equal importance when regulating and providing guidance to
state stormwater programs. For example:
- Develop and field-test BMPs specifically designed to manage stormwater
in a manner protective of ground water in different hydrogeological settings
(e.g., karst, sand and gravel).
- Ensure that states may utilize §319 funds to conduct research and
demonstration projects, and to develop and field-test BMPs specifically
designed to manage stormwater in a manner that is protective of
ground water.
To State Agencies:
- Establish better coordination among stormwater management, ground
water protection, underground injection control (UIC), and water quality
monitoring programs so that programmatic overlaps can be elimnated and
opportunities for collaboration in protecting surface and ground waters
can be identified and initiated.
- Review stormwater management plans and total maximum daily load
(TMDL) determinations from a ground water program perspective to
ensure protection and conservation of the resource.
To Local Governments:
- Protect all water resources through local stormwater management activities,
and require the use of stormwater BMPs (including ongoing maintenance
and monitoring), stormwater utilities, and stormwater management
plans that are designed to conserve and protect both surface water and
ground water and promote natural ground water recharge.
A green roof in Chicago, Illinois. In addition to their ecological,
aesthetic, and temperature-moderation values, green roofs dramatically
reduce the volume of stormwater runoff and the peak flow
rate. Rapid runoff from roof surfaces can result in flooding,
increased erosion, and the discharge of contaminants directly into
surface and ground water. A green roof can absorb stormwater and
release it slowly over a period of several hours.
Photo: Susanne Jespersen
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