Draft Imnaha Subbasin Summary November 30, 2001 Prepared for the Northwest Power Planning Council Subbasin Team Leader



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Water Quality

The entire Imnaha River channel and some stream reaches in key tributaries are listed on the 303(d) list for summer temperatures exceeding the desired 500F for adult bull trout or 640F for salmonid rearing (Figure 9) (ODEQ 1996). Big Sheep Creek is also listed for habitat modification from the confluence with the Imnaha River upstream to Owl Creek (ODEQ 1996). Table 8 provides stream reaches within the Imnaha River subbasin that qualify for 303(d) listing, whileTable 9 provides information about how the listings relate to State standards.
Table 8. Imnaha River watershed 303(d) listings (ODEQ 1996)

Watershed

Reach

Parameter

Criteria

Season

Big Sheep Creek

Mouth to Owl Creek

Habitat Modification




Temperature

Rearing 64°F (17.8°C)

Summer

Big Sheep Creek

Owl Creek to Wilderness Boundary

Temperature

Oregon Bull Trout 50°F (10°C)


Summer

Grouse Creek

Mouth to headwaters

Temperature

Rearing 64°F (17.8°C)

Summer

Gumboot Creek

Mouth to Headwaters

Temperature

Rearing 64°F (17.8°C)

Summer

Imnaha River

Mouth to Summit Creek

Temperature

Rearing 64°F (17.8°C)

Summer

Imnaha River

Summit Creek to North/South Fork Confluence

Temperature

Oregon Bull Trout 50°F (10°C)

Summer

Lick Creek

Mouth to Mud Springs Cr.

Temperature

Oregon Bull Trout 50°F (10°C)

Summer

Lightning Creek

Mouth to Headwaters

Temperature

Rearing 64°F (17.8°C)

Summer




Lower Imnaha subbasin

The lower Imnaha River (mouth to Summit Creek) is listed on the Oregon Department of Environmental Quality’s 303d list for summer temperatures. The seven-day moving average of daily maximum temperatures recorded in 1995 below the town of Imnaha was 69.1F, with 21 days exceeding temperature standards of 64F (ODEQ Data). The only 303d-listed tributaries occurring in the lower Imnaha subbasin are Lightning Creek and Grouse Creek. Temperatures recorded in 1993 (65.5F) at a USFS monitoring site on Lightning Creek exceeded state standards, however zone fisheries biologists and hydrologists contend the current temperature regime to be within the natural potential, given the low elevation grassland ecosystem, the size of the drainage basin, and limited amount of riparian modifications (Wallowa-Whitman National Forest 1998). In 1992 the seven-day moving average of daily maximum temperatures recorded on Grouse Creek was 65.3F (ODEQ data).

Big Sheep Creek

Water temperatures in Big Sheep Creek, from its confluence with the Imnaha up to the wilderness boundary, exceeded State standards on numerous occasions (ODEQ Data). From its mouth to Owl Creek, the seven-day moving average of daily maximum temperatures was 69.6F in 1992 and 64.4F in 1993. In addition, the State bull trout temperature requirement of 50F has been regularly exceeded in the upper portion of Big Sheep Creek (from Owl Creek to the wilderness boundary). Stream temperatures recorded at USFS monitoring stations in the Big Sheep Creek subwatershed are shown in Table 10. Zone fisheries biologists and hydrologists suggest that Big Sheep Creek, above the Wallowa Valley Irrigation Canal, be removed from the 303d list, as water temperatures in this area may currently be within their natural potential (Wallowa-Whitman National Forest 1998). The State has currently not responded to this concern.

Table 9. Grande Ronde standards, applicable to the Imnaha, used in 303(d) (OAR 340-041-0722) listings (Oregon Administrative Rules Composition 1998, pp 5-298 – 5-302)


Factor

Desired Habitat Condition for Salmon

1Oregon State water quality standards for the Grande Ronde River Basin

Temperature

2/40-57F for spawning and incubation, 38-68 F for adult migration, and 39-68 F is the optimum range for freshwater rearing (juvenile fish prefer 54-57 F)

No measurable surface water temperature increase is allowed in:

  • A basin for which salmonid rearing is a designated beneficial use, and in which surface water temperatures exceed 64F (17.8C)

  • In waters and periods of the year determined by ODEQ to support native salmonid spawning, egg incubation, and fry emergence from the egg and from the gravels in a basin which exceeds 55.0F (12.8C)

  • In waters determined by ODEQ to support or to be necessary to maintain the viability of native Oregon bull trout, when surface water temperatures exceed 50.0F (10.0C).

  • In waters determined by ODEQ to be ecologically significant cold-water refugia

  • In stream segments containing T&E species if the increase would impair the biological integrity of the T&E population

  • In Oregon waters when the d.o. levels are w/in 0.5 mg/l or 10% saturation of the water column or intergravel DO criterion for a given stream reach or subbasin

Dissolved Oxygen (DO)


2/Adult migration=greater than 7.0 mg/L; Spawning and incubation=greater than 8.0 mg/L; Rearing=greater than 7.0 mg/L

>11.0 mg/l from spawning until fry emergence, or >9.0 mg/l if spatial median = >8.0 mg/l. Where conditions of barometric pressure, altitude, and temperature preclude attainment of the 11.0 mg/l or 9.0 mg/l criteria, d.o. levels shall be > 95% saturation

Chlorophyll a

Use State standard

Concentration greater than 0.015 mg/L is an indicator of nuisance algal growth.

Streamflow

Streamflow should provide access to adequate spawning gravel, and stream depth should be no less than 18 cm.

2/Spawning velocity of 1 to 2.25 f/s, maximum adult migration velocity of 8 f/s

No standard for streamflow, however, there are instream water rights on many streams

Turbidity

2/Turbidity should be limited and not sustained

No more than a 10% cumulative increase in natural stream turbidities is allowed.

Bacteria Standards
(Fecal coliform)

Use State standard
  • 30-day log mean of 126 E. coli organisms/100 ml, based on a minimum of 5 samples


  • No single sample shall exceed 406 E. coli organisms per 100 ml

  • Raw sewage (untreated) discharge is prohibited

Runoff contaminated with domesticated animal wastes shall be minimized and treated to the maximum extent possible

Total dissolved solids (TDS)

Not established

200 mg/l

pH

Use state standard

6.5 – 9.0

Pesticides

Pesticide dependent – use State standard

Current State and Federal regulations


Figure 9. 303d listed streams of the Imnaha subbasin.

Upper Imnaha subbasin

The mainstem Imnaha, from Summit Creek to the North/South Fork confluence, violates State temperature standards for bull trout and is on the Oregon Department of Environmental Quality’s 303d list. The seven-day moving average of daily maximum temperatures measured in 1993 at Indian Crossing and Nine Point Creek were 56.2F and 61.5F (respectively), exceeding the bull trout temperature standard of 50F (Wallowa-Whitman National Forest 1998). Similarly, the seven-day moving average of daily maximum temperatures measured by the Oregon Department of Environmental Quality in 1995 at Coverdale Camp ground was 57.2F (ODEQ data). Zone fisheries biologists and hydrologists contend that the inclusion of the upper mainstem Imnaha (from Ollokot Campground to the North/South Fork confluence) on the 303d list should be reevaluated given the size of the river and limited riparian modification (Wallowa-Whitman National Forest 1998). The State of Oregon has not addressed these concerns.

The only 303d-listed tributary in the upper Imnaha subbasin is Gumboot Creek. The moving seven-day maximum stream temperature in Gumboot Creek was 66F, measured in 1992.

Table 10. Seven-day moving maximum stream temperatures (F) recorded at USFS monitoring stations in the Big Sheep Creek subwatershed (from USDA Forest Service et al. 1998b)



Site

Year

May

Jun

Jul

Aug

Sep

Oct

Big Sheep @ Echo Canyon

1989

1990


1991

1992


1993

1994


36

49

47



50

51

48



38

59

52



62

55

64



40

66

65



N/A

60

71



42

68

67



N/A

65

71



45

63

62



N/A

61


46

57

56



56

54

50



Big Sheep @ Lick Creek

1991

1992


1993

1994


1995

1996


56

N/A


51

N/A


N/A

N/A


51

67

54



63

48

N/A



65

67

59



70

54

64



66

68

64



69

61

64



61

59

59



61

59

60



55

50

52



N/A

48

52



Big Sheep below canal

1993

1994


1995

47

N/A


N/A

N/A

57

42



54

65

52



59

65

55



55

57

54



49

N/A


44

Big Sheep above canal

1996

1997


N/A

N/A


N/A

N/A


51

57


51

55


50

53


46

48


Lick Creek @ mouth

1990

1991


1992

1994


1995

1996


1997

47

45

N/A



46

N/A


N/A

N/A


57

50

N/A



61

51

N/A



N/A

64

63

65



67

58

63



59

65

64

66



67

60

62



60

60

56

51



58

57

58



56

53

N/A


N/A

46

48



51

50


Little Sheep @ FS boundary

1996

N/A

N/A

59

58

57

54

Cabin above canal

1996

N/A

N/A

51

51

50

46

McCully @ USFS boundary

1996

N/A

N/A

52

51

50

46


Redmont Creek above canal

1989

45

54

56

N/A

N/A

N/A

Land Use


Approximately 75 percent of the Imnaha subbasin is under public ownership (Figure 10). The majority of the subbasin lies within the Wallowa-Whitman National Forest, with management by three Ranger Districts (Eagle Cap, Hells Canyon National Recreation Area, and Wallowa Valley). Each Ranger District maintains distinct mandated management directives, ranging from the least restrictive in the Wallowa Valley Ranger District to the most restrictive in the Eagle Cap District.

Ranching and grazing, timber harvest, transportation, mining, recreation, and agriculture are primary forms of land use considered to have potentially affected terrestrial and aquatic resources in the subbasin (Figure 11).



Ranching and Grazing

The first domestic livestock grazing known for the Imnaha were Nez Perce horses in the early 1700’s (Wallowa-Whitman National Forest 1998). Estimates for the number of horses grazed are around 1,000. The Nez Perce also grazed as many as 500–650 cattle in the Imnaha following their introduction in the mid 1800’s (Chalfant 1974; Womack 1996, cited in Wallowa-Whitman National Forest 1998). In the late 1800’s, settlers brought in large herds of sheep and cattle, the effects of which can still be seen today around seeps, springs and some stream segments where the native fescue plant communities were removed (Ashe et al. 2000).

As in much of the western U. S., the number of cattle grazing in the Imnaha peaked in the late 19th century and has declined since (Johnson 1982, cited in Wallowa-Whitman National Forest 1998). Despite the decline, cattle grazing remains the major land use activity on private lands in the Imnaha subbasin (Beamesderfer et al. 1997). There are 29 existing grazing allotments on federal land within the Imnaha watershed (Wallowa-Whitman National Forest 1998). At least two of these allotments are not currently being used: one in the upper Imnaha in the Wallowa Mountains and another in the Hat Point area (H. Lyman, Wallowa-Whitman National Forest, personal communication, 08 February 2001). Five large allotments in the lower reach of the watershed are used fall, winter, and spring. Most of the remaining allotments are small and associated with individual residences on private land along the river corridor.

Sheep grazing, once prevalent in the Imnaha subbasin, no longer occurs. A record of decision signed in 1995 formally terminated sheep grazing in the subbasin. The primary goal of the removal of sheep from the area was to reduce potential interaction between domestic and bighorn sheep (refer to wildlife discussion below). The HCNRA was grazed through the 1996 season, at the end of which all allotments occurring in the area became vacant. The Eagle Cap Wilderness Area was grazed through the end of the 1998 season and became vacant in 1999 (D. Bryson, NPT, personal communication, May, 2001).

Figure 10. Land ownership in the Imnaha subbasin


Figure 11. Land use patterns in the Imnaha subbasin
Evidence of grazing exists throughout the watershed including streambank disturbances, soil compaction, and changes to plant communities (Wallowa-Whitman National Forest 1998). Grazing and cattle allotments in the Grouse, Big Sheep and Little Sheep watersheds have contributed to reduced water quality (increased nutrients) and fish habitat degradation (reductions in shade-providing vegetation). Feedlots, located on private lands along Little Sheep Creek and the lower mainstem Imnaha, contribute varying amounts of nutrients to surface water (Nez Perce Tribe et al. 1990), most notably following localized, high-intensity thunderstorms (B. Smith, ODFW, personal communication, April 12, 2001). The impacts of this pollution on the aquatic environment are, however, considered to be short in duration and scope due to the volume and velocity of flows in the affected areas (B. Smith, ODFW, personal communication, April 12, 2001). More excessive grazing impacts to the aquatic and terrestrial environment are believed to occur in the upland areas of the subbasin (B. Smith, ODFW, personal communication, April 12, 2001).

Recently, strategies have been implemented to improve vegetative cover and retention of soil protecting vegetation. For example, the current management of active livestock allotments has placed increased emphasis on attainment of forage utilization standards, riparian management standards and objectives, and improved control over livestock operations by both the Forest Service and permittees (Wallowa-Whitman National Forest 1999). There has also been a downward trend in AUMs in recent years and an upward trend in the number of cross fences, exclosures and off-stream water developments constructed in or near riparian areas. The Wallowa-Whitman National Forest has recently excluded three miles of stream (a total of six miles of fence) from livestock, and has completed 38 upland exclosures, ensuring protection of springs, seeps, wetlands, intermittent draws, perennial nonfish-bearing streams, ephemerals, and ponds (J. Platz, Wallowa-Whitman National Forest, personal communication, May, 2001). The Forest Service has also planted coniferous and deciduous trees along 19 miles of stream channel deficient in riparian vegetation.



Timber and Special Forest Products Harvesting


Prior to 1950, the majority of timber harvested in the Imnaha subbasin was large-diameter Douglas fir, ponderosa pine and western larch trees accessible from roads (USDA Forest Service 2000a). Even-aged timber management practices increased in the late 1950’s, due to the growing demand for timber products. Extraction techniques included the use of animals or tractors for skidding logs along haul routes located in creek bottoms or draws (USDA Forest Service 2000a). The first prescribed clearcut in the subbasin was implemented in the Gumboot Butte area in the late 1950’s (USDA Forest Service 2000a). An estimated 20% of the basin contained saw lumber in 1960 (OWRB 1960 cited in Beamesderfer et al. 1997). In 1992, clearcutting was eliminated as a harvest method on the Wallowa-Whitman National Forest (USDA Forest Service 1994; USDA Forest Service 1998a).

Establishment of the Eagle Cap Wilderness in 1964 (PL 88-577) precluded logging in that portion of the subbasin. Designation of the Hells Canyon National Recreation Area in 1975 (PL 94-199) also changed timber management practices in the Imnaha subbasin, restricting harvest to uneven-aged stands only (Wallowa-Whitman National Forest 1998; USDA Forest Service 2000a).

Timber harvest on federal lands in the Imnaha subbasin has declined from nearly 80,000 mbf to 1,200 mbf in the last 20 years (Wallowa-Whitman National Forest 1998). Total acreage harvested within the Imnaha subbasin from 1989 to 1997 was approximately 11,918 acres (USDA Forest Service 2000a). Of this amount, approximately 2,017 acres were clearcut and 9,901 acres were partial cut (USDA Forest Service 2000a). The reduction in harvest is in response to the changing management emphasis from commodity production to resource protection. Establishment of the Eagle Cap Wilderness in 1964, designation of the HCNRA in 1975, designation of the Imnaha as a Wild and Scenic River in1988, ESA listings for chinook salmon in 1992, 1994 federal land use regulations, ESA listings for bull trout in 1998, and various high priority watershed designations have drastically reduced timber harvest on USFS lands within the Imnaha River watershed. Current methods of harvest on federal lands are restricted to salvage logging and selective thinning only (USDA Forest Service 2000a). Silvicultural activities such as tree planting, cone harvesting, cone tree selection, and precommercial thinning occurs throughout the watershed where timber has been removed by harvest or fire (USDA Forest Service 2000a).

Today, harvest only occurs in USFS Management Area 1 on the Wallowa Valley Ranger District and USFS Management Area 11 in the HCNRA. These two management units comprise 21% of the watershed, or 57,913 acres. The units are located in the southern portion of the watershed and are characterized by flat ridge tops and timbered draws (USDA Forest Service 2000a). Many of the timbered stands (27,152 acres) in the Imnaha subbasin are less than 30 years old, a result of insect infestations, windstorms, harvest and fire. For example, in the Big Sheep Creek subwatershed, the 1989 Canal Fire consumed considerable portions of the upper drainage, which contributed to the current 9,139 timbered acres that are 30 years old or less (USDA Forest Service 2000a).

Special forest product harvesting (e.g. poles, Christmas trees, firewood) is only permitted in Management Units 1, 3, 6, 10, and 11, and only to the extent that it does not adversely impact wildlife or aquatic biota (Wallowa-Whitman National Forest 1998). PACFISH buffer stipulations prohibit harvesting near streams and other water bodies. Buffers range in size from 300’ for perennial fish-bearing streams to 100’ for intermittent streams and other water bodies.

Transportation


Roads established along the mainstem Imnaha River, Big Sheep and Little Sheep creeks during early settlement remain in use today, although they have been improved. From the late 1970’s to 1985, the miles of road constructed on the Wallowa-Whitman National Forest doubled from 4,350 miles to over 8,700 miles (McIntosh et al. 1994). Currently, 1,292 miles of open and closed roads exist in the Imnaha watershed (USDA Forest Service 2000a). Of these, 834 miles occur on lands administered by the Wallowa-Whitman National Forest, and 438 miles occur on private, state, and BLM land (USDA Forest Service 2000a).

The overall road density for open and closed roads (all management jurisdictions) is 1.52 miles of road per square mile of land (USDA Forest Service 2000a). On that portion of the watershed not administered by USFS, the road density (open and closed) is 1.43 miles of road per square mile, compared to USFS-administered land where it is 1.05 miles per square mile (land area includes non-roaded wilderness). Road densities in USFS-managed non-wilderness areas may be higher than in other areas of the watershed. Generally, road densities on federally administered lands fall within the Forest Plan Standards and Guidelines of less than 2.5 miles of open roads per square mile of land.

In two subwatersheds of the Imnaha, road densities are considerably higher than the road density for the watershed as a whole (Wallowa-Whitman National Forest 1998). The Gumboot subwatershed has 3.2 miles of open road per square mile of land, while the upper Imnaha (near RM 55) subwatershed has 3.66 miles of open road per square mile of land.

Although the actual road density in the Imnaha may not be as high as that found in similar subbasins, the combination of steep topography and historic construction practices have contributed sediment to stream channels. A common road construction practice by the USFS and other entities was to sidecast the excess or “overburden” material as the road was being built (Mason et al. 1993). Invariably, much of this material would enter stream channels due to the inherently steep gradient common to the drainage. The USFS now endhauls this material to designated dumpsites.

During the winter of 1952-53, road construction activities along the Imnaha River (Road 3955) triggered a rockslide approximately 15 miles above the town of Imnaha. The deposition of material posed a serious barrier to fish migration, albeit partial, for at least two years (Beamesderfer et al. 1997). Similarly, USFS road #3900, which borders Gumboot Creek, posed a potential sediment source to the channel due to the undermining effects of the 1997 flood. The road has recently been completely rebuilt.

In response to sedimentation, wildlife harassment, and access concerns, the USFS has closed, restricted access and decommissioned several roads and/or road segments on federally administered lands. In 1990 and 1991, 14.4 miles of road were closed (6.8 miles were obliterated) and 659 acres of roadbed seeded (USDA Forest Service 2000a). Road obliteration projects have occurred in the Ferguson, Big Sheep and West Fork Carrol Creek subwatersheds. Road relocation projects, designed to ameliorate sedimentation to streams, have occurred along a five-mile section of USFS road #3900 between the Imnaha River and Lonesome Saddle (USDA Forest Service 2000a). Seasonal road use restrictions between October and December are implemented to protect soils and wildlife habitat, minimize harassment of wildlife, maintain adequate bull [elk] escapement and promote quality hunting. These seasonal restrictions, otherwise known as Cooperative Travel Management Areas or Green Dot Closure Areas, are those roads not marked by a carbonite stake with a green dot at the road intersection.

Since 1989, Forest Service road maintenance has been performed every one to seven years depending on circumstances and road use (Wallowa-Whitman National Forest 1998). In 1990, a full time position was established at the Wallowa Mountains Engineering Zone to coordinate the Access and Travel Management Program, including annual maintenance (USDA Forest Service 2000a).


Mining


Gold, silver, copper and cinnibar mining have all occurred in the Imnaha watershed (Wallowa-Whitman National Forest 1998; Ashe et al. 2000). Placer mining began in the 1890s and continued until World War I; hydraulic dredging techniques were employed beginning in the early 1900s as a more efficient technique to work placer gravels. Mining was concentrated around the mouth and in the upper Imnaha from Ollokot campground to Indian Crossing campground (Wallowa-Whitman National Forest 1998). Overall, mining activities have not severely degraded riverine habitat (Beamesderfer et al. 1997).

There are currently no active mining claims in the Imnaha watershed (Wallowa-Whitman National Forest 1998), however some hobby mining still occurs (Ashe et al. 2000). Regulations associated with the establishment of the HCNRA, Eagle Cap Wilderness, and Imnaha Wild and Scenic River Management Plan withdrew lands associated with these areas from mineral entry. The remainder of the watershed, although open for mineral entry, is unlikely to be mined as it is composed entirely of basalt, which does not contain a marketable source of minerals. Although basalt is crushed to produce paving gravel, given its abundance throughout the region, it is unlikely that basalt in the Imnaha would be exploited for this purpose because of its remoteness from developed areas that require large quantities of paving gravels.



Recreation

The Imnaha watershed provides a variety of recreational activities, and because of the Wilderness designation, the Wild and Scenic designation, and the Hells Canyon National Recreation Area designation, it draws a wide variety of users (Wallowa-Whitman National Forest 1998).

During winter months, snowmobilers, cross-country skiers and alpinists comprise the majority of recreationalists. The “Sno-Park” at Salt Creek Summit is a major use area during the winter, providing access to portions of the Eagle Cap Wilderness and Imnaha subbasin. The Mountain Loop Road (a.k.a. Gumboot Road, or 39 road) is not plowed past the Salt Creek Sno-Park during the winter, nor are roads plowed past the Pallette Ranch on the main Imnaha River Road (RM 42.8).

During summer months, hiking, horseback riding, fishing, hunting and camping are popular recreational activities within the subbasin. Foot and pack animal travel are allowed within the trail system. Within the Eagle Cap Wilderness, there are 59 miles of trail, which was used by more than 1000 people in 325 groups in 1997.

The watershed contains eight developed campgrounds, three scenic viewpoints, and multiple trailheads. The increased use of developed and undeveloped campgrounds has compacted soil horizons, and negatively impacted the various flora and fauna inhabiting respective sites. In an effort to address this problem, the Wallowa-Whitman National Forest recently completed five campground rehabilitation projects in the subbasin. Included in the projects were plantings, campsite relocation away from streams, installation of educational signs, and the definition of access routes within the riparian area (J. Platz, Wallow-Whitman National Forest, personal communication, May, 2001).


Urban Development


Commercial development within the Imnaha watershed is restricted to the small town of Imnaha (population 25), which consists of a café, store and tavern, gas station, motel, and a GTE field office (Wallowa-Whitman National Forest 1998). Community buildings include an elementary school, library, post office, and church. There are also home-based businesses and a privately owned lodge, outfitter and guide services.

Private residences are scattered along the river corridor, including the Imnaha River Woods subdivision, a privately owned housing development. Hydrologists have expressed concern over the amount of bank armoring adjacent to dwellings and structures, fearing that the rip rap will alter downstream flow regimes and channel morphology (T. Carlson, Wallowa-Whitman National Forest, personal communication, April 12, 2001). Current land use regulations passed by the Wallowa County Planning Commission restrict the sale of land for subdivision. In general, the pattern of settlement and use of private land within the watershed has not changed much since the 1940s, and many descendents of the original settlers still reside in the Imnaha Valley.



Agriculture

Farming in the Imnaha subbasin began in the mid to late 1800’s with settlement of the watershed by non-Indians (Ashe et al. 2000). Relative to total subbasin area, a proportional amount of the Imnaha is used to raise cattle and to a lesser extent grow barley, wheat, and hay (Wallowa County Chamber of Commerce 2001). The primary effects agricultural activities have had on natural resources in the Imnaha has been associated with channelization efforts to protect cropland and infrastructure (homes, outbuildings, barns, etc.), sediment inputs, and irrigation withdrawals (Ashe et al. 2000). Agricultural spraying is minimal (Nez Perce Tribe et al. 1990). Although the majority of irrigation withdrawals have negligible effects on the streams and rivers, the Wallowa Valley Improvement Canal significantly affects flows in the Big and Little Sheep Creek watersheds, as it maintains a 120 cfs water right on Big Sheep Creek, Little Sheep Creek, and all associated streams, seeps, or springs (Ashe et al. 2000).


Protected Areas


The Imnaha River mainstem, from its headwaters to its mouth (excluding the North Fork), was included in the Oregon Omnibus Wild and Scenic Act of 1988. The Imnaha subbasin is protected from impoundment due to provisions set forth in the Act. From RM 80 to RM 65 (headwaters to Indian Crossing) the Imnaha maintains a ‘Wild River’ designation. From RM 65 (Indian Crossing) to RM 22 (Cow Creek Bridge) the river is classified as ‘Recreational’, and from RM four to RM zero, the Imnaha maintains a ‘Scenic River’ designation (Wallowa County-Nez Perce Tribe 1993). All of the Imnaha Wild and Scenic area occurs in the HCNRA except from the town of Imnaha to Fence Creek. Approximately 36,711 acres of the upper drainage occur within the Eagle Cap Wilderness, which is managed according to provisions set forth under the Wilderness Act of 1964 (Public Law 88-577) (Wallowa-Whitman National Forest 1998).

In 1988, the Northwest Power Planning Council directed extensive studies of existing habitat in an effort to 1) identify fish and wildlife resources of critical importance to the region, 2) establish the degree to which mitigation projects would affect the areas, 3) assess the effects of hydroelectric development on the areas and 4) determine whether or not areas should be protected from future hydroelectric development. The studies provided the Council with a means upon which to designate certain river reaches as “protected areas” based on their productive capacity, unique habitat, or risk of loss to fish and wildlife species of concern. The list for the Imnaha was completed in 1994 and is shown in Table 11. These and other areas in the Imnaha subbasin with unique protection status are shown in Table 12 and F.

Table 11. Protected areas in the Imnaha subbasin based on reviews conducted by the Northwest Power Planning Council, 1994 (http://www.streamnet.org).


Watershed/

Reach

Protected Category

Total Stream Miles

Total Stream Miles Protected

Percent in Protected Status

Imnaha mainstem

Anadromous and resident fish & wildlife

88.10

71.41

81.04

Imnaha mainstem

Resident fish only




10.00

11.35

Cow Creek

Anadromous only

29.10

14.60

50.17

Lightning Creek

Anadromous only

48.90

27.80

56.85

Horse Creek

Anadromous only


34.00

17.70

52.06

Big Sheep Creek

Anadromous only

186.00

108.00

57.88

Freezeout Creek

Anadromous only

8.30

7.90

95.18

Grouse Creek

Anadromous only

27.90

20.90

74.91

Summit Creek

Anadromous only

7.00

4.40

62.86

Crazyman Creek

Anadromous only

7.00

5.40

77.14

Gumboot Creek

Anadromous only


9.90

3.00

30.30

Dry Creek

Anadromous only

8.00

5.00

62.50

Skookum Creek

Anadromous only

4.30

0.89

20.70




Total:

371.00

296.99

80.05

Table 12. Areas in the Imnaha subbasin that are managed and/or protected using a conservation-based strategy




Site

Location

Acreage

in subbasin (approximate)

Agency

Type of Protection/Management

Eagle Cap Wilderness


Upper 15 miles Imnaha

41,610

USFS


Managed and protected under the Wilderness Act of 1964

Imnaha Wild and Scenic River

Mainstem Imnaha River

9,354

USFS, ODF

Managed and protected under the Wild and Scenic Rivers Act of 1968

Little Sheep Wildlife Area

Little Sheep Creek

(@ approx. RM 5.0)



510

ODFW

Managed for the protection of wildlife habitat

Hells Canyon National Recreation Area

Imnaha River corridor

249,844

USFS, ODFW, NPT

Managed and protected under the National Recreation Area Act

Nez Perce (Nee-Me-Poo) Natl. Historic Trail

Lower 16 miles of Dug Bar road

16 linear miles

USFS (11mi)

Private

Managed under the Nez Perce National Historic Trail Act of 1986


Bonner Flat Proposed Research Natural Area

Upper South Fork Imanha

1662

USFS

Managed for the preservation of the natural ecosystem

Duck Lake Proposed Research Natural Area

Edge of Eagle Cap Wilderness Area

337

USFS

Managed for the preservation of the natural ecosystem

Basin Creek Proposed Research Natural Area

Imnaha River above Horse Creek

735

USFS

Managed for the preservation of the natural ecosystem

Clear Lake Ridge

Little Sheep Creek drainage (RM 6.0)

3455

Nature Conservancy

Managed for the preservation of the natural ecosystem

Zumwalt Prairie Conservation Area

Camp Creek




Nature Conservancy

Managed for the preservation of the natural ecosystem

Figure 12 Areas in the Imnaha subbasin that are managed and/or protected using a conservation-based strategy


Fish and Wildlife Resources




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