Clark Public Utilities
Project: Water Supply Development
Location: Clark County, Washington
Clark Public Utilities (CPU) is the water purveyor for much of Clark County,
one of the fastest growing areas in Washington. Since 1990, PGG has helped
CPU develop water supplies in an ongoing effort to meet its ever-increasing
demands. The utility obtains water from a network of production wells
that tap aquifers created by the ancestral Columbia River.
As in many parts of western Washington, groundwater development is limited
by a variety of factors. First, much of the water in the shallow aquifers
is contaminated as a result of land use activities; in deeper aquifers,
water often contains naturally high levels of iron and manganese. Second,
many aquifers — especially the shallow ones — are hydraulically
connected to streams, and pumping from wells may impact flows in these
streams. In addition, water rights are difficult to obtain, and any approaches
to development must consider impacts to the rights of nearby users.
Our strategy has focused on identifying areas where sufficient high-quality
groundwater could be developed and where impacts to surface water and
other users would be minimal. As a result, we have characterized much
of Clark County’s hydrogeology, assessed regional trends in water
quality, and used various methods — including digital flow models
— to predict the effects of pumping at proposed wellfield sites.
We have also modeled the complex interactions between groundwater and
Our work has resulted in more than 20 pilot and production wells that
now supply an additional 8 million gallons of water per day. We sited,
designed, and tested these wells.
Modeling / Clark Public Utilities: Remedial Investigation and Groundwater
Assessments / Clark Public Utilities: Salmon Creek Basin Management Plan