WRIA 62 WMP 032305 - Washington State Department of Ecology

March, 2005 -45- 023-1289-003.3040
local input into flood related issues in Pend Oreille County. At present, the Watershed Planning Unit
does not have a unified message to convey. A message reflecting the views of the Watershed
Planning Implementing Body will be necessary prior to pursuing management actions related to
flood control in WRIA 62. During development of this issue, the Watershed Planning Unit noted
that any representative of the Watershed Planning Implementing Body that becomes involved in
forums related to flood control will need to be sensitive to representing the pos ition of the
Implementing Body and not their own personal position or the position of their employer or
affiliation. In practice this means that any representative of the Implementing Body cannot represent
the position of the Implementing Body regarding flood control within WRIA 62 without the prior
consensus of the Implementing Body.
4.1.4.1 Dams in the Pend Oreille River Watershed
Based on available flow information, the average annual flow of the Pend Oreille River at Newport
(the upstream boundary of WRIA 62) is about 25,680 cfs and the average annual flow of the Pend
Oreille River downstream of Boundary Dam (close to the downstream boundary of WRIA 62) is
26,990 cfs (Entrix, 2002). This indicates that only about 1,300 cfs total runoff to the Pend Oreille
River on an average annual basis is derived from WRIA 62. The remainder of the flow within the
Pend Oreille River in WRIA 62 is derived from the watershed upstream of WRIA 62. This watershed
spans about 26,000 square miles, comprises the watershed of the Clark Fork River, Pend Oreille Lake
and the Pend Oreille River in Idaho and includes the fourth and fifth largest lakes in the United States,
Flathead Lake and Pend Oreille Lake, respectively. The Clark Fork – Pend Oreille watershed is also
highly regulated, as illustrated by Figure 4-5 which shows the locations of the dams within the
watershed. Table 4-2 lists the important (in terms of flood control) dams and reservoirs within and
upstream of WRIA 62.
The dams which have the greatest control on flows and elevations within the Pend Oreille River in
WRIA 62 include Hungry Horse Dam in the upper Clark Fork watershed in Montana and Albeni Falls
Dam, located in Idaho, about 2.5 miles upstream of WRIA 62 (Figure 4-5). Within WRIA 62, there
are two dams on the Pend Oreille River (Figure 4-5), Box Canyon Dam (located at River Mile 34.4,
2.5 miles north of Ione) and Boundary Dam (located at River Mile 17 about one mile south of the US-
Canadian border). Box Canyon Dam and Boundary Dam have some control on river elevations in
certain reaches and at specific times according to operating procedures. In addition, the Power House
Dam, located within the Calispell sub-basin has some potential to influence stream flows locally.
The following sections provide information on these facilities.
4.1.4.1.1 Dams Managed by Federal Agencies
Dams and hydropower operations managed by the federal government are governed by operating
curves and environmental constraints that are met through individual projects’ responses to biological
opinions and other regulations. Federal dams in the Clark Fork – Pend Oreille watershed that have
the most impact on WRIA 62 Pend Oreille River flows and river elevations are Hungry Horse Dam
and reservoir on the Flathead River which is managed by the Bureau of Reclamation (BOR) and
Albeni Falls Dam on the Pend Oreille River in Idaho which is managed by the Army Corps of
Engineers (ACOE). Both these projects are Federal Columbia River Power System (FCRPS) dams.
The FCRPS dams are operated to implement the current actions called for in the 2000 National
Marine Fisheries Service and US Fish and Wildlife Service Biological Opinions (BiOps) as well as
non-Biological Opinion related requirements and purposes such as flood control. At present the year
2000 National Marine Fisheries Service Biological Opinion for the FCRPS dams is in remand per US
WRIA 62 WMP 032305