Groundwater Under the Pacific Northwest
Stevenson, Washington
Pre-Conference Field Trip, November 1, 2005
For much of the world, groundwater is the source of the most precious resource for humans--water. As part of the 2005 Conference, “Groundwater Under the Pacific Northwest,” in Washington, 32 people from a variety of public sector agencies and private businesses toured Clark County Washington, to understand groundwater as a resource and the issues surrounding it.
The
group had lunch at the City of Vancouver’s Water Resource Education Center,
a place fitting for groundwater education: it is a center “committed to
teaching people of all ages how to make wise decisions about water.” After
lunch, Steve Prather of Clark Public Utilities (CPU) led us through copies
of hydrogeologic cross-sectional maps to give us a sense of the geology
of the aquifers under Clark County. While it would seem that there would
be ready sources of groundwater in the Upper and Lower Troutdale Aquifers
underlying most of the county, Steve pointed out throughout the day how
CPU is struggling to provide adequate water for Clark County’s growing
population. Clark has had a 45 percent population growth over the last
ten years.
After the introduction, we boarded the bus. The bus was luxurious and it felt more like we were headed on a tour of the English countryside then Clark County, especially considering the weather. It became immediately apparent that despite the stereotypical Northwest weather (rain….rain… rain) and the perfect geology for collecting groundwater, this tour would highlight the challenges in maintaining this resource for the demands of the growing population of the area.
The first location visited was the area surrounding Vancouver Lake. It is a mixture of industry, Port of Vancouver operations, and wetlands habitat. We learned here that one issue constraining groundwater availability is contamination. The eastern part of this area is heavily contaminated with trichloroethylene (TCE), a chemical that is used as a solvent to clean heater parts. Its mishandling has resulted in groundwater contamination. As we left the area, we traveled through the Fruit Valley neighborhood that currently requires ventilation systems to help clear TCE vapors that would otherwise accumulate in residences. While the contamination only results in a relatively small amount of direct loss of groundwater availability, it also impinges on installing new wells nearby in an otherwise highly desirable area. Water withdrawals from proposed wells and changes in the direction of the TCE plume could cause entrainment towards new residences and the local elementary school.
The
connection between surface water and groundwater was made apparent by
our stop at Lewisville Park in the north part of the county. It turns
out that in addition to the extraordinary expansion of human population
in the region, there is another player in the groundwater equation: salmon.
The Lewis River is spawning ground for several anadromous species, and
the discharge is impacted by groundwater withdrawal. With the blistering
pace of population growth in the nearby city of Battleground, enormous
pressures are placed on groundwater resources. To balance human population
growth and habitat requirements, players like CPU are looking for tidal
influence areas near the main stem of the Columbia River. These wells
can withdraw water with less impact on upland surface water availability
to wildlife. This nexus to salmon has drawn CPU into riparian restoration
projects such as the Darling Riparian project which focuses on revegetation.
It was ironic to pass warning signs during our bus tour reading, “Caution: water over roadway.” Even in the northwest, where water appears (over)abundant, contamination, tremendous population growth, and the maintenance of minimal habitat standards confound easy answers to the use of groundwater resources.
Some
thoughts from other participants:
"Driving through the fast-growing City of Battleground, I was struck by the challenges that our region must face to ensure we have adequate supplies of water to fuel this fast-paced growth. The days of just dropping a new well are gone. Today we must bring market-based incentives to free up existing water rights and encourage regional solutions and intergovernmental cooperation to meet this fast-growing demand.” --Jay Hamachek, Director of North American EHS & Business Development
“All
the future drinking water wells will come from the Columbia River floodplain
or county lowlands area. As one goes north and east, the Sand and Gravel
Aquifer is much closer to the surface. Drawing from it would affect surface
water flows. Pumping drinking water that affects surface water would bring
up all kinds of issues: ESA, surface water pollution, etc. Drilling in
the lowlands and tidally-influenced areas avoids these conflicts. The
issue with drilling in the lowlands is the higher probability of contamination
from an old dump site that has contaminated an aquifer. One example is
the city of Ridgefield. Part of the Port of Ridgefield contains contaminated
soil from a wood treatment facility (now closed). Toxics from the facility
have contaminated the aquifer below Ridgefield and it is now being cleaned
up. They had to move their drinking water source well, however, because
it was right next to the port!” --Jason Wolf, Clark County Public
Works, Clean Water Program