Restoration Plan Summary

The WRIA 55 watershed plan update developed to meet the requirements of RCW 90.94 includes two key components: 1) an estimate of new domestic water use from new homes using individual wells constructed between 2018 and 2038, and 2) a set of projects and actions that will offset the potential impact of those wells on stream flows and aquatic habitat.

Estimated Water Demand

Each County utilized historical building permit data to estimate the number of new homes likely to be built between 2018 and 2038 in WRIA 55 that will utilize an individual well for a water source. The projection for each County is:

County

Homes

Spokane County

2,182

Stevens County

246

Pend Oreille County

332

Total

2,760


Generally accepted per capita indoor water use and a localized assessment of the size of irrigated landscape was used to estimate the consumptive water use (water that does not return back to the aquifer) associated with each home.  The annual water use at the end of 20 years is estimated to be:

County

Water Use (acre-feet/year)

Spokane County

2,058

Stevens County

108

Pend Oreille County

188

Total

2,353


Projects and Actions


The plan update includes projects that directly offset impacts to streamflow from new water withdrawals by increasing streamflow and projects that benefit aquatic resources through enhancing aquatic habitat.

Types of Water Offset Projects included in the plan update

Water Right Acquisitions – Water rights that are currently in use are acquired and the water use is retired.  The reduction of water withdrawals benefits streamflow.

Managed Aquifer Recharge – Water is diverted from a stream during high flow periods to an off-stream infiltration gallery.  The added water raises the water table above natural conditions and induces additional groundwater inflow into the stream during the low flow months.

Surface Water Storage – Surface water storage projects involve the retention of surface water when water is physically and legally available, for later release during critical low streamflow periods.

Water Supply Source Exchange – Use of alternative sources for water supply that lessen or eliminate impacts at the original water source location, providing streamflow benefits to adjacent surface water bodies from cessation of use at the former source location.

Types of Non-Water Offset Projects included in the plan update

Fish Barrier Removal – These projects involve replacing or modifying culverts to remove barriers to fish passage, thereby increasing available accessible habitat.

Flood Plain Restoration - Restoration can include reconnecting side channels and other modifications to stream channel morphology, levee modifications, and enhancement of associated riparian vegetation.

Habitat Restoration/Enhancement – Habitat restoration projects can include enhancing riparian vegetation, placing woody debris, gravel augmentation, and other activities that improve habitat.

Land Acquisition – These projects include acquisition (or easements) that protect land from future development and allow preservation and restoration of upland and riparian habitat to preserve and enhance the aquatic environment.

Water Conservation – These projects focus on public outreach efforts to encourage water conservation.