WRIA 62 WMP 032305 - Washington State Department of Ecology

March, 2005 -40- 023-1289-003.3040
• Since most of the groundwater supply wells completed in the unconsolidated sand and gravel
aquifers in WRIA 62 are shallow and relatively close to surface water, there is a potential that
some of these wells are under the influence of surface water. Ultimately, these wells will have to
comply with guidelines set forth by Washington State DOH (DOH, 2003).
• For both the Pend Oreille River and its tributaries, site specific information, such as baseflow
hydrograph evaluation and seepage runs, may be needed to make determinations on the nature of
the hydraulic interaction between surface water and groundwater.
Based on population projections, the highest population growth rates (and therefore anticipated future
water demand) are predicted to occur within the southern sub-basins, including Calispell, Davis,
Skookum, Kent and McCloud and along the mainstem of the Pend Oreille River from the Idaho stateline
north to the Ione (Figure 4.2). It is therefore these areas where population growth and water
supply are expected to be a potential concern.
Appropriation of water from the WRIA 62 sub-basins are limited by Ecology administered surface
water source limitations (SWSLs) pursuant to RCW 77.55.050 which states,
“It is the policy of this state that a flow of water sufficient to support game fish and food fish
populations be maintained at all times in the streams of this state. The director of ecology
shall give the director notice of each application for a permit to divert or store water. The
director has thirty days after receiving the notice to state his or her objections to the
application. The permit shall not be issued until the thirty-day period has elapsed. The
director of ecology may refuse to issue a permit if, in the opinion of the director, issuing the
permit might result in lowering the flow of water in a stream below the flow necessary to
adequately support food fish and game fish populations in the stream. The provisions of this
section shall in no way affect existing water rights.”
Those streams on Ecology’s Surface Water Source Limited (SWSL) list in WRIA 62 have been
identified to have limitations in available water supply as a result of fisheries concerns. The WRIA
62 streams on the SWSL list are included on Table 4-1 and illustrated on Figure 4.3. In addition,
WDFW has recommended that Ecology not grant water rights that have the potential to impact small
streams with less than 5 cfs mean annual flow or water rights from the mainstem of the Pend Oreille
River when the seven-day low flow falls below 7,700 cfs. As shown on Figure 4-3 and Table 4-1, the
Calispell, Davis and Skookum sub-basins are considered to have “limitations” with respect to
available water supply and are on the SWSL list. In addition the available flow records for Kent and
McCloud Creeks (Golder, 2005) indicate that the mean annual flows of these streams are less than 5
cfs. So, in effect, the sub-basins where growth is anticipated in WRIA 62 are closed to further
appropriation by SWSLs unless the appropriation of the water can be shown not to impact surface
water pursuant to RCW 77.55050.
The majority of the hydrogeolgic information reviewed and assessed within Phase II of the watershed
planning process is not sufficiently detailed to completely quantify groundwater resources. However,
conceptual hydrologic and hydrogeologic models can be used to establish hydraulic continuity in
many situations. Groundwater withdrawals, including domestic exempt wells, must not impair senior
water rights nor affect the flow of any surface water body (RCW 90.44.030). In addition, Ecology
considers groundwater to be in continuity with surface water in a sub-basin with surface water
WRIA 62 WMP 032305