GROUNDWATER DEVELOPMENT
• CPU Water Supply
• McAllister Springs Wellfield
• Tumwater Groundwater Study

PROPERTY TRANSFER
REMEDIAL INVESTIGATION & CLEANUP
EXPERT WITNESS
WELLHEAD PROTECTION
SOLID WASTE COMPLIANCE
WATER RIGHTS SUPPORT
DATA MANAGEMENT
GROUNDWATER MODELING
WATERSHED ASSESSMENT
AQUIFER STORAGE & RECOVERY
WASTEWATER & STORMWATER RECHARGE
 

Client: Clark Public Utilities
Project: Water Supply Development
Location: Clark County, Washington

Background
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.

Challenges
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.

Approach
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 surface water.

Outcome
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.

Related Projects

Groundwater Modeling / Clark Public Utilities: Remedial Investigation and Groundwater Flow Model

Watershed Assessments / Clark Public Utilities: Salmon Creek Basin Management Plan

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