Mill Creek Master Plan
Main Report - Volume 1

Section 5—Management Unit Descriptions and Objectives

a. Description of Management Units.

The MCP has been divided into 19 individual management units. A management unit is a tract of land designated to achieve, or contribute towards the achievement of, project objective(s). An important part of each management unit is the RO. Each management unit RO communicates a site-specific application of the project-wide objectives identified in section 3. In combination, these RO's tend to wholly, or partially, satisfy regional needs, as well as the expressed desires of other agencies and the public, within the limits and capabilities of the project resource base. Each management unit is assigned a name that is related to some local physical feature.

b. Composition of Management Units.

The management units, as described in this section, contain the following components: 1) land classification; 2) acres; 3) unit description; 4) influencing and constraining factors; 5) resource objectives; and 6) development and management concepts. The following paragraphs contain a detailed outline and explanation of the components listed under each management unit.

(1) Name of Management Unit.

Each management unit has a specific name assigned to it for ease of identification.

(2) Land Classification.

There are six land classifications: Project Operations, Recreation, Mitigation, Environmentally Sensitive Area, Multiple Resource Management (MRM), and Easement Lands. The MRM is further divided into two subclasses: Recreation, Low Density; and Wildlife Management General. These classifications are defined in section 4, and identify the primary management functions of each management unit at MCP. The management units in this section are grouped by the classifications and subclassifications.

(3) Acres.

The total number of acres contained in the management unit.

(4) Unit Description.

A description of the ecological, cultural, and aesthetic features found within the management unit.

(a) Ecological Factors.

1. Landform.

A description of the landform.

2. Elevation.

Elevation (altitude) range (also refer to volume 2, plate 3-1).

3. Percent of Slope.

The steepness of the slopes (also refer o volume 2, plate 3-2).

4. Aspect.

The direction(s) the unit faces (i.e., north, south, etc.). Also refer to volume 2, plate 3-3.

5. Soils.

A list of the types of soils contained within the management unit (also refer to volume 2, paragraph 3.02.c., Soils, and plate 3-5).

6. Land Cover/Vegetation.

A list of cover types (also see volume 2, plate 3-6) and trees and shrubs inventoried at the management unit. A list of trees, shrubs, forbs, and grasses can be found in volume 2, Supporting Data, Item 7.

7. Water Resources.

The names and types of streams or water sources in, or next to, the management unit (perennial flow 90 percent of the year, intermittent flow 50 percent of the year, and ephemeral flow less than 50 percent of the year).

8. Wildlife and Fish Resources.

A list of wildlife species that may be found at the management unit (refer to volume 2, section 3; and Supporting Data, Items 8 and 9).

(b) Cultural Factors.

1. Access.

The type of available access to the management unit (i.e., roads, trails, etc.). Also refer to volume 2, section 3, paragraph 3.03.d., Transportation.

2. Utilities.

Utilities used, or available within close proximity to the management unit.

3. Land Ownership/Management.

The Government and/or agency that owns the land, as well as the agency responsible for management of the unit.

4. Outgrants.

The grantee, contract number, purpose, and type of instrument. It also includes the real estate outgrant that allows the use of project lands by other agencies or individuals (see volume 2, section 3, plate 3-11, and table 3-24).

5. Adjacent Management Units.

A list of other management units that are contiguous to the specified management unit.

6. Adjacent Ownership/Management Outside Project.

The Government or other agency that owns, and is responsible for management of, the lands immediately adjacent to the project boundary. If the land is owned by an individual or corporation, it will be identified as private.

7. Existing Developments.

Developments and facilities found at the management unit.

8. Visitor Use.

Type of recreational pursuits available at the management unit (i.e., sightseeing, picnicking, and boating).

9. Archaeological/Historical Resources.

A list of archaeological/historical resources that once existed, or currently exist, within the management unit (also refer to the CENPW Cultural Resource Management Plan).

(c) Aesthetic Factors.

A list of visual and/or auditory and olfactory factors within, or perceived from, the management unit.

(5) Influencing and Constraining Factors.

Summary of conditions that may limit or promote the implementation of proposed objectives. It also includes a discussion of potential environmental, social, and administrative tradeoffs that may occur in the future.

(6) The RO's.

(a) Objective.

Group of brief statements specifying the RO's for each management unit. Most management units have more than one objective. Primary objectives are presented in upper case letters. Other than identifying primary objectives, objectives have not been prioritized.

(b) Rationale.

A discussion of the need and intent of each specific RO.

(7) Development and Management Concepts.

The development and management concepts section contains a detailed description of the uses, developments, and management techniques that should be undertaken to implement the RO's. The concepts discussed in this section are not all-inclusive but, rather, are intended to convey an understanding of the type of development and the management strategies and techniques envisioned for implementing the objectives. The ultimate decisions regarding the method(s) of objective implementation rest with the Operational Management Plan. Plates 5-2 through 5-20 illustrate the existing and potential project development concepts. Readers should refer to these plates as they study discussions of specific management units. Plate 5-1 is a plate (map) index for all of the management units.

5.02. Project Operations

Five management units, totaling 107.0 acres, are classified as Project Operations:

• Mill Creek Diversion (17.5 acres)
• Mill Creek Dam (22.0 acres)
• Mill Creek Office and Information Center (1.8 acres)
• Mill Creek Channel (13.7 acres)
• Virgil B. Bennington Lake (51.9 acres)

These management units contain the facilities that allow for flood control and operation, as well as the administration of the entire project.

a. Mill Creek Diversion Management Unit.

(1) Land Classification: Project Operations.

(2) Acres: 17.5.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: This management unit is located along Mill Creek floodplain, and in a cut through the cliff.

2. Elevation: Range 1200 to 1250 (0.1 acre) and 1250 to 1200 (17.4 acres).

3. Aspect: Flat (11.9 acres), north (3.2 acres), southeast (0.3 acres), southwest (0.1 acre), west (0.4 acre), and northwest (1.4 acres).

4. Percent of Slope: 0-7 (11.9 acres), 8-15 (2.4 acres), 16-25 (0.1 acre), and 25+ (3.1 acres).

5. Soils: YmA--Yakima Silt Loam, 0 to 3 percent (13.5 acres); and WaD--Walla Walla Silt Loam, 8 to 30 percent (4.0 acres).

6. Land Cover/Vegetation: U-F--Upland Field (2.6 acres; U-S--Upland Shrub (0.3 acre); W-OW-- Open Water (1.6 acres); W-PE--Palustrine Emergent (3.3 acres); W-PS--Palustrine Scrub Shrub (1.2 acres); UB-P--Project Structures (4.7 acres); R-DT--Riparian Deciduous Trees (0.8 acre); and U-D--Upland Disturbed (3.1 acres).

7. Water Resources: Mill Creek.

8. Wildlife Resources: Riparian-dependent birds and furbearers.

9. Fish Resources: Steelhead passage, resident rainbow trout, and sculpins.

(b) Cultural Factors.

1. Access: Rooks Park Road and service roads.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Washington State Department of Transportation, 62-13 Access Road, Easement.

5. Adjacent Management Units: Mill Creek ESA, Rooks Park, Bennington Habitat, and South Mill Creek Trail.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Diversion facilities, diversion levee, first debris barrier, second debris barrier, Diversion Dam (with anadromous fish ladder), and Intake canal hiking, sightseeing.

8. Visitor Use: Walking on levees or crossing the end of the intake channel, when dry.

9. Archaeological/Historical Resources: Refer to the CENPW Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: The diversion levee blends with the surrounding landscape and offers a view of Rooks Park Management Unit and Mill Creek ESA. Diversion Dam is small scale, and does not impose on the landscape.

2. Negative: The height of the diversion levee blocks views from Rooks Park.

(4) Influencing and Constraining Factors. The diversion facilities were designed to help protect the city of Walla Walla from flood, as authorized by public law. The area behind Diversion Dam fills with gravels and sediments, and needs to be dredged out periodically to ensure proper operation of flood control facilities. This area is also considered a wetland and, as such, requires special environmental considerations and permits.

(5) Resource Objectives.

(a) Resource Objectives.

1. ENSURE CONTINUED SAFE AND EFFICIENT OPERATION OF DIVERSION FACILITIES FOR FLOOD CONTROL.

2. Provide visitors with an aesthetically pleasing environment.

3. Enhance visitor opportunities to view and understand the project.

4. Provide safe and efficient passage of adult and juvenile anadromous fish to and from their subbasin habitat.

5. During dredging operations, take into account anadromous fishery and wildlife habitat values and all opportunities to enhance these habitats, as well as the effective utilization of dredge materials on the project.

(b) Rationale.

1. This management unit is needed to meet the project's authorized purpose of flood control.

2. The unit is highly visible to the public from Rooks Park, South Mill Creek Trail, and Constitutional Trail.

3. There is currently no interpretive information available for this portion of the flood control operations. Information should be made available to the public to help them understand the project's components.

4. Anadromous fishery resources are important to the local communities and the region. Safe and efficient passage, allowing acceptable but very limited stress conditions, is essential for the viability of the fisheries.

5. There is a periodic need to dredge an area behind Diversion Dam to ensure the efficient operation of both Diversion Dam and the intake canal. The area that needs to be dredged has anadromous fisheries, and is a valuable wildlife habitat. the dredge material can be used in the South Mill Creek Management Unit and in old borrow sites near the lake.

(6) Development and Management Concepts. Refer to plate 5-2 for a conceptual development plan for the Mill Creek Diversion Management Unit.

b. Mill Creek Dam Management Unit.

(1) Land Classification: Project Operations.

(2) Acres: 22.0.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Mill Creek Dam, located across a small side draw of Russell Creek.

2. Elevation: Range 1150 to 1270 (1.5 acres), 1200 to 1250 (10.4 acres) and 1250 to 1270 (10.1 acres).

3. Aspect: Flat (1.0 acre), northeast (1.5 acres), east (2.1 acres), south (0.2 acre), and southwest (9.1 acres).

4. Percent of Slope: 0-15 percent (1.0 acre), 15 to 25 percent (2.8 acres), and 25+ percent (17.7 acres).

5. Soils: None.

6. Land Cover/Vegetation: UB-P--Project Structures/Water Development (21.4 acres), U-F--Upland Field (0.6 acre), and U-D--Upland Disturbed (0.034 acre).

7. Water Resources: Adjacent to Virgil B. Bennington Lake.

8. Wildlife Resources: The disturbed habitats on this unit provide some minimal habitat values to small mammal, reptile, and avian species.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: Reservoir road, Bennington Lake Road, and Dam Service Road.

2. Utilities: Telephone lines.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Pacific Northwest Bell underground communication cable.

5. Adjacent Management Units: Virgil B. Bennington Lake, Bennington Lake Recreation Area, Bennington Lake Road, Bennington Habitat, and Russell Creek Habitat.

6. Adjacent Ownership Outside Project: No portion of this management unit contains a project boundary.

7. Existing Developments: Mill Creek Dam, operators house, piezometers, and 42-inch discharge pipe.

8. Visitor Use: Hiking and horseback riding across the top of the dam, and sightseeing from the dam.

9. Archaeological/Historical Resources: None.

(c) Aesthetic Factors.

1. Positive: Mill Creek Dam is faced with brown native basalt. The rock face blends in well with the landscape, both in color and texture. The height of the dam offers a panoramic view of the lake and the Russell Creek Valley.

2. Negative: A pipe, aluminum in color, on the face of the dam stands out and does not blend with the dam.

(4) Influencing and Constraining Factors. The MCP was authorized primarily for flood control. There is seepage around the right abutment, which contributes to some seepage from the reservoir.

(5) Resource Objectives.

(a) Resource Objectives.

1. ENSURE CONTINUED SAFE AND EFFICIENT OPERATION OF MILL CREEK DAM.

2. Provide visitors with an aesthetically-pleasing environment.

3. Enhance visitor opportunities to view and understand the project.

(b) Rationale.

1. Mill Creek Dam is a primary structure in providing flood control in the Walla Walla Valley.

2. The dam can be seen from the lake recreation area, the lake, and the surrounding trails. Because of high visitor recreation use and visitor expectations, project structures should blend into the natural landscape as much as possible.

3. A high percentage of the public is unaware that the Corps operates MCP. They are also unaware of the functions of Mill Creek Dam and other water resource facilities on the project.

(6) Development and Management Concepts. Refer to plate 5-3 for a conceptual development plan for the Mill Creek Dam Management Unit.

c. Virgil B. Bennington Lake Management Unit.

(1) Land Classification: Project Operations.

(2) Acres: 51.9.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Lake basin behind dam.

2. Elevation: Range 1177.2 to 1205 (51.9 acres). Also see volume 2, table 3-32, for acreage at different lake elevations.

3. Aspect (of lake bottom): Flat (31.8 acres), north (6.8 acres), southeast (0.9 acre), southwest (0.4 acre), and west (3.4 acres).

4. Percent of Slope: 0-7 percent (12.2 acres), 8 to 15 percent (5.5 acres), 16 to 25 percent (2.8 acres), and over 25 percent (3.4 acres).

5. Soils: WlB--Walla Walla silt loam, lacustrine substratum, 0 to 8 percent (38.5 acres); WlD--Walla Walla silt loam, lacustrine substratum, 8 to 30 percent (10.0 acres) and Mill Creek Dam (3.4 acres).

6. Land Cover/Vegetation: Submerged aquatic species within the inlet channel. U-F--Upland Field (2.0 acres); U-SP--Upland Deciduous Saplings (0.1 acre); U-DT--Upland Deciduous Trees (0.03 acre); U-D--Upland Disturbed (0.28 acre); R-F--Riparian field (1.3 acres); R-S--Riparian Shrub (1.7 acres); R-DT--Riparian Deciduous Trees (3.7 acres); L-OW--Lacustrine Open Water (19.8+ acres) - this varies; and L-UB--Lacustrine Unconsolidated Bottom (22.8 acres).

7. Water Resources: Virgil B. Bennington Lake.

8. Wildlife Resources: Waterfowl, beaver, and mink. The lake and its adjacent vegetation is valuable to all types of wildlife at MCP.

9. Fish Resources: Rainbow trout (stocked), smallmouth bass, and some forage fish species.

(b) Cultural Factors.

1. Access: Bennington Lake Road and East Service Road.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Bennington Lake Recreation Area, Mill Creek Dam, and Bennington Habitat.

6. Adjacent Ownership Outside Project: This management unit does not extend to any project boundary.

7. Existing Developments: Intake tower.

8. Visitor Use: Fishing, boating, and swimming.

9. Archaeological/Historical Resources: Refer to the CENPW Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Open 52-acre lake at elevation 1205 in the spring. Only public lake within a 28-mile radius.

2. Negative: Unvegetated exposed shoreline when pool is below elevation 1205. After inflows are stopped in the spring, the 1205 lake level drops due to evaporation and seepage. The lower the lake level, the higher the negative aesthetic effects.

(4) Influencing and Constraining Factors.

Because the primary purpose of Virgil B. Bennington Lake is flood control, the lake has fluctuated up to elevation 1241. The lake level is determined by seasonal runoff and irrigation water demand. Maintenance of the lake level at elevation 1205 may compete with the need for instream perennial flows into Mill Creek Channel for irrigation supply and anadromous fish passage.

Due to high flows and lack of irrigation demand requirements, the lake is near normal conservation pool elevation 1205 at the beginning of the recreation season (June 15). Starting in the late spring, usually around May, flows are lower and irrigation demands begin stopping the inflows to the lake. The lake levels then drop due to evaporation and seepage. During drought years, the lake may never reach conservation pool and, during heavy runoff years the lake level will be held below conservation pool until July to accommodate floodwaters. The evaporation and seepage problem in the reservoir limits the ability to maintain pool elevation.

Soils and silt substrates, along with the degree of water surface elevation fluctuations of the lake, make the establishment of shoreline and submergent vegetative cover difficult, without adequate substrate preparation.

The lack of suitable spawning habitat and limited rearing conditions for salmonids currently prevents the maintenance of viable populations within the lake.

The occurrence of water-borne parasites and occasional high fecal coliform concentrations hinders the establishment of a formal bathing-beach area.

(5) Resource Objectives.

(a) Resource Objectives.

1. SAFELY MANAGE LAKE LEVELS TO PROVIDE AUTHORIZED PURPOSES OF FLOOD CONTROL AND RECREATION, AS WELL AS FISH AND WILDLIFE BENEFITS.

2. Hold the water elevation of the lake stable at 1205 feet as long as possible.

3. Manage for stocked rainbow trout and smallmouth bass fisheries by enhancing the diversity of cover and benthic prey organisms.

4. Actively manage to improve the water quality of the lake for biotic and recreational purposes. Water was not diverted into the lake only for flood control.

5. Manage for wildlife values.

6. Provide for water-oriented recreational opportunities.

(b) Rationale.

1. The MCP was authorized primarily for flood control in the 1940's. In the early 1950's, however, both Federal and State agencies quickly realized the opportunity to provide the public with enhanced opportunities by filling the lake for recreation and fishery habitat.

2. The stability of Virgil B. Bennington Lake would allow for full utilization of recreational facilities such as fishing, boating, and swimming. It provides an aesthetically-pleasing, natural lake appearance, as well as many benefits to fish, wildlife, and water quality. This is especially important during the recreation season and the smallmouth bass spawning season.

3. The Walla Walla area is limited in water-oriented recreational opportunities close to the human population. Virgil B. Bennington Lake provides for one of the only popular fishing lakes for one of the only popular fishing lakes for many people in the surrounding area. To maintain gamefish populations to meet public demand, the WDW manages the lake primarily by stocking it with rainbow trout. No spawning of rainbow trout occurs within the lake or its inlet due to inadequate availability of gravel substrate, low dissolved oxygen, high temperatures, and operational water level fluctuations. Smallmouth bass also inhabit the lake, providing additional fishing opportunities to the public. Bass can tolerate higher water temperatures and lower dissolved oxygen levels than salmonids, but spawning requires a greater degree of water surface elevation stability. Habitat improvement projects would be highly beneficial, and can be readily identified for the implementation plan.

4. The water quality in Virgil B. Bennington Lake degrades throughout the season due to stagnation under higher water temperatures and low pool elevations resulting from lack of inflow due to competition with irrigation withdrawals. The resultant lack of rooted vegetative production contributes to the limited potential of the lake. The fishery potential cannot be realized without maintaining sufficient water quality, such as dissolved oxygen levels. Water seeps from the lake at the substrate interface level, which causes some degree of flow-through depending on water surface elevation level. The stabilization of the water surface near 1205 feet would benefit this exchange of water and retard the effects of stratification on water temperature, thus alleviating effects of stagnation.

5. The variety of surrounding wildlife, both resident and migrational, are dependent on the lake for a water supply. Hiding cover corridors to the water line become critical for survival from predation, especially for the juvenile portion of the populations. currently, when the lake elevation drops below 1205, there is no hiding cover next to the lake.

6. Virgil B. Bennington Lake is the primary recreational opportunity on the project. The lake is a unique recreational resource in the Walla Walla Valley, with close access to the area's 50,000 residents. Fishing from the shoreline and non-motorized boating are the primary recreational activities on the lake.

(6) Development and Management Concepts.

Refer to plate 5-4 for a conceptual development plan for the Virgil B. Bennington Lake Management Unit.

Provide for a 1205-foot elevation conservation pool for as long a period of time as possible in the spring for smallmouth bass spawning, and in the summer for recreational opportunity and water temperature moderation, and in the fall for winter fisheries.

Water rights allow the Corps to withdraw water from Mill Creek to the lake in the fall. Doing so to refill Virgil B. Bennington Lake to elevation 1205 would provide better water quality for the overwintering of fish.

The WDW considers Virgil B. Bennington Lake primarily for stocked put-and-take trout. The lake is a stratified fishery with some smallmouth bass over rainbow trout, and provides suitable spawning habitat for rainbow trout in the lake. Rainbow trout rearing and smallmouth bass spawning is limited by operational water level fluctuations and the lack of benthic prey organism production. Selected bathymetric areas of the lake can be deepened. Piles of rock and root wads should be supplemented, as well as weed mat base, in selected shoreline areas at depths below the managed water surface fluctuation elevation.

d. Mill Creek Office and Information Center Management Unit.

(1) Land Classification: Project Operations.

(2) Acres: 1.8.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat triangular area along Mill Creek, between Yellowhawk Creek, Mill Creek Return Canal, and Bennington Lake Road.

2. Elevation: 1150 to 1200 (1.8 acres).

3. Aspect (of lake bottom): Flat (1.8 acres).

4. Percent of Slope: Flat (1.8 acres).

5. Soils: YmA--Yakima silt loam, 0 to 3 percent (1.8 acres).

6. Land Cover/Vegetation: U-F--Upland Field (1.4 acres), and UB-P--Project Structures/Water Development (0.0001 acre).

7. Water Resources: Yellowhawk and Mill Creeks.

8. Wildlife Resources: Waterfowl, beaver, and mink.

9. Fish Resources: Anadromous steelhead, resident rainbow trout, and sculpins.

(b) Cultural Factors.

1. Access: Reservoir Road (county) and Bennington Lake Road.

2. Utilities: Electric and telephone.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Bennington Lake Road, Mill Creek Channel, and South Mill Creek Trail.

6. Adjacent Ownership Outside Project: No part of this management unit is on a project boundary.

7. Existing Developments: Mill Creek Return Canal.

8. Visitor Use: None.

9. Archaeological/Historical Resources: Refer to the CENPW Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Currently undeveloped, with native grasses and shrubs.

2. Negative: None.

(4) Influencing and Constraining Factors.

The current office and maintenance facilities located at Yellowhawk Park do not meet current needs, regulations, codes, and guidelines. Locating these facilities in the management unit would better serve the project operation and maintenance, and better serve the public. Additionally, the lands used by these office and maintenance facilities at Yellowhawk Management Unit would better serve as a picnic area along Mill Creek. The existing buildings are an eyesore, and do not give the public a professional view of the Corps.

(5) Resource Objectives.

(a) Resource Objectives.

1. PROVIDE SAFE AND EFFICIENT MAINTENANCE AND ADMINISTRATION OF THE PROJECT.

2. Provide visitors with an aesthetically-pleasing environment.

3. Enhance visitor information and opportunities related to understanding and use of the project.

(b) Rationale.

1. The present office and maintenance facilities are up to 50 years old, and do not meet current regulations and guidelines. The current location is more valuable for picnicking and public use than for maintenance. Relocating the office and maintenance area would better serve the project and the public, and would better meet current standards and regulations.

2. The existing office and maintenance facilities are unattractive with the high security fence, exposed maintenance area, and the building built for other uses around 50 years ago. The public is entitled to an aesthetically-pleasing environment.

3. There is no area in the existing office set aside for visitor information. Because MCP is a public facility, the public has the right to understand project operations, resources, and potential visitor usage.

(6) Development and Management Concepts.

• Refer to plate 5-5 for a conceptual development plan for this management unit.
• Relocate the office and maintenance area to this management unit.
• Provide Visitor Information center.

e. Mill Creek Channel Management Unit.

(1) Land Classification: Project Operations.

(2) Acres: 13.7.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Water, and its associated bathymetry, within the boundaries of the channel's high water mark for Mill Creek and the Garrison-Yellowhawk Creek confluence area.

2. Elevation: 1150 to 1200 (5.8 acres), 1200 to 1250 (7.8 acres), and 1250 to 1300 (0.1 acre).

3. Aspect (of lake bottom): Flat (13.7 acres).

4. Percent of Slope: 0 to 3 percent (13.7 acres).

5. Soils: YmA--Yakima silt loam, 0 to 3 percent (13.7 acres).

6. Land Cover/Vegetation: R-OW--Riverine Open Water (13.1 acres) and UB-P--Project Structures/Water Development (0.6 acre). Native, with introduced riparian trees and shrubs.

7. Water Resources: Perennial flow downstream from the dam at Rooks Park through the diversion works at the project office complex to Garrison and Yellowhawk Creeks. Intermittent flow downstream from the diversion works of the Mill Creek Channel to the project boundary.

8. Wildlife Resources: Wading birds, songbirds, migratory waterfowl, amphibians, and mink. The riparian habitat within and adjacent to this management unit is valuable to all types of wildlife existing on MCP.

9. Fish Resources: Steelhead, rainbow trout, bull trout (possible corridor), sculpins, some forage fish species, and benthic invertebrates.

(b) Cultural Factors.

1. Access: Mill Creek Recreational Trail, South Mill Creek Trail (South Levee Service Road).

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Mill Creek Recreation trail, Rooks Park, Mill Creek Diversion, South Mill Creek Trail, MCP Office and Information Center, and Yellowhawk Recreation Area.

6. Adjacent Ownership Outside Project: Private, State of Washington (Walla Walla Community College), and Walla Walla County (Mill Creek Flood Control Zone District).

7. Existing Developments: Channelized stream corridor with concrete weirs, riprap sides, First Division Works, fish ladder, concrete stream crossing, and large boulders placed for fish habitat.

8. Visitor Use: Fishing and wading/swimming.

9. Archaeological/Historical Resources: Refer to the CENPW Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Water feature, clear-flowing stream, color of weirs and riprap are a dark hue that blends, and adjacent cottonwood vegetation.

2. Negative: Series of concrete weirs, riprap on the side of the channel, lack of streamside vegetation, and relatively even width with uniform water depths. Below Division Dam, dry channel following the diversion of water to Yellowhawk-Garrison Creeks (usually between May/June and the fall).

(4) Influencing and Constraining Factors.

Seasonal runoff, the city of Walla Walla municipal water withdrawals, and the small amount of irrigation withdrawal determines flows in Mill Creek Channel to Diversion Dam near Rooks Park. In the spring and during times of flooding, water is diverted at Diversion Dam to Bennington Lake. Flows between Diversion Dam and Division Dam at the Project Office are perennial. At Division Dam, approximately 70 cfs of water is diverted to Yellowhawk and Garrison Creeks. This means that, between early summer and fall, all of the water in Mill Creek Channel is diverted and the channel is dry below Division Dam. This results in extremely poor water quality, or no water at all.

The objective to maintain Virgil B. Bennington Lake at elevation 1205 for as long a period as possible may compete and interfere with the need for providing adequate perennial flow in Mill Creek Channel.

In the Mill Creek Channel, the demand for irrigation withdrawal, in conjunction with the construction of concrete cascading weirs and vegetative removal to maintain channel capacity and efficiency in 1986, has made the establishment of instream and near-shore vegetation difficult. The lack of vegetationwithin the channel allows no capacity for water temperature moderation through shading or for an organic foodbase that supports the benthic invertebrates that are forage for fish.

Steelhead are the dominant anadromous fish species using this portion of the project. Chinook salmon have generally been gone from Mill Creek since around the 1920's. Bull trout are resident and have a fluvial lifestyle higher up the creek system in the subbasin. Single large boulders were placed in a triangulated pattern for salmonid refugium in the mid-1980's. Suitable spawning substrate for salmonids is present within sections of the channel, although these areas are only moderately usable due to embeddedness and profuse algal growth on the cobble gravel substrate during low-flow operation. Since active management of the channel for flood dissipation and water diversion began, it has been typically viewed that the channel was used primarily as a migrational corridor for adult anadromous fish, and that the migrating fish continue upstream to spawn in the subbasin. This assumption would still require the management of the channel for adequate passage conditions in respect to water supply (flow) and quality, adequate forage, and resting areas. Adult steelhead, unlike the various salmon species, do not always die following their spawn, and may forage during their migration. Maintenance of flow within the channel for the smolt outmigration has been less of a concern because the main Mill Creek Channel through Walla Walla is typically functional during the spring with greater flow volumes. The water quality and high temperatures below Walla Walla are the greater concern for blockage or modified anadromous passage behavior. Water quality degrades as water supply decreases during the summer, forcing steelhead to follow the stable flow conditions of Yellowhawk Creek.

(5) Resource Objectives.

(a) Resource Objectives.

1. MANAGE CHANNEL TO PROVIDE AUTHORIZED PURPOSES OF FLOOD CONTROL AND RECREATION, AS WELL AS FISH AND WILDLIFE BENEFITS.

2. PROVIDE ADEQUATE PERENNIAL FLOW LEVELS FOR ADULT AND JUVENILE ANADROMOUS FISH PASSAGE SEASONS DURING UPSTREAM MIGRATION FROM YELLOWHAWK AND GARRISON CREEKS INTO THE MILL CREEK CHANNEL, AS WELL AS THE MILL CREEK CHANNEL BELOW THE DIVERSION PRIOR TO THE TIME WHEN LOW STREAMFLOWS ELIMINATE WATER IN THE MILL CREEK CHANNEL BELOW THE YELLOWHAWK-GARRISON DIVISION.

3. Coordinate with other Government agencies and private organizations in actively pursuing and coordinating the acquisition of water rights and streamside land parcels in critically determined problem areas in Mill Creek and the Walla Walla River to alleviate the cumulative effects of elevated temperature and poor water quality.

4. Provide for resting and feeding pool areas, in conjunction with the concrete cascades. Allow woody riparian species (as much as possible without interfering with flood control) to grow to provide temperature moderation.

(b) Rationale.

1. All vegetation within the channel was removed in 1986 to improve channel efficiency. At the request of WDW, large boulders were sparsely placed as mitigation for the needs of all fish lifestyles and likely provides refugium more beneficial to predator fish. A more diverse habitat structure, including vegetation patches, is warranted. Vegetation not only provides hiding cover from predators, but also provides for temperature moderation, attachment substrate for invertebrate prey species, and sedimentation traps.

2. Due to constraints of irrigation and municipal water withdrawals leading to elevated temperatures and poor water quality below the city of Walla Walla, most anadromous fish utilize the more stable perennial flows of Yellowhawk and Garrison Creeks. This response intensifies the importance of maintaining adequate flows in these creeks for anadromous fish population viability. Adult steelhead must have at least 1.5 to 2.0 vertical feet of water in the channel to safely pass upstream.

3. The Corps cannot manage land under other ownership, and can be constrained with coordination demands. The Corps does have the expertise to restore parcels of land deemed important to project or system operation for the enhancement of fishery resources. By managing critical areas of the creek, system-wide anadromous fish production can be rehabilitated without relying solely on the uncertainty of managing secondary creek systems with less capacity for sustaining fish populations. A local cooperating interest in fishery enhancement presently exists. Walla Walla High School has an interest in a cooperative effort with the Corps and WDW to implement habitat improvement and possible hatchery projects along their portion of Yellowhawk Creek. A local steelhead sportsman organization currently operates an adult trap for a small hatchery operation on Yellowhawk Creek. The group is allowed to supplant 25,000 fry out of its Henry Canyon facility on Mill Creek. Sufficient coordination needs to occur between hatchery interests and efforts to ensure adeqaute escapement to subbasin habitats for natural spawning.

4. The original construction of the concrete cascading weir system resulted in pools below the weirs of about 4 to 6 feet deep. These pools provided resting and feeding areas for adult anadromous salmonids on their upstream migration by partially imitating the natural pool/riffle/run system of the original creek. Pools below the weirs also provided for areas needed for acceleration so that adult fish can safely traverse a weir. The regulated flows since construction of the weirs have caused substrate material to fill in areas behind and below the weirs, thus reducing the diversity of fish habitat to which anadromous fish have adapted.

(6) Development and Management Concepts.

Refer to plate 5-6 for a conceptual development plan for this management unit.

Provide for a minimum instream eprennial flow resulting in 2 feet of water depth at the highest elevational point in the channel annually from 15 March through 15 September for safe and efficient passage of juvenile and adult steelhead. This minimum flow provision needs to be maintained through the Yellowhawk and Garrison Creek diversion to provide adequate passage conditions for steelhead and resident fish in their efforts to reach subbasin spawning areas. Suitable spawning habitat for salmonids does not exist in this portion of the channel due to low-flow management, resulting in embedded substrate, elevated temperatures, low oxygen transfer in the water and through the gravels, and rofuse algal growth as a result of dissipated water velocities and high solar radiance. This accumulated algal growth becomes stagnated with more reduced flows, and the species composition dominated by filomeztom (scum-forming green algae) is not conducive to the support of a diversity of benthic invertebrates important as forage for fish. Enhancement of instream woody species capable of providing seasonal shade, and the addition of randomly distributed groups of boulders (as opposed to single angular boulders), would provide successional conditions and organic forage input for a greater diversity of benthic invertebrates.

To further destabilize the present channel conditions toward a more productive seasonally dynamic system, pools should be recreated (by excavation) below every second or third concrete cascading weir. These pools would contribute to increased diversity in habitat and species composition, and provide for salmonid feeding and rearing areas, while still maintaining the needed energy dissipating conditions for flooding flows. Consideration should be given to allowing for a periodic flooding event through the channel to scour accumulated sediments and maintain the pool's beneficial attributes.

5.03. Recreation

There are five management units, totaling 68.4 acres, that are classified Recreation:

• Rooks Park (18.4 acres)
• Bennginton Lake Recreation Area (14.4 acres)
• Bennington Lake Road (24.4 acres)
• Yellowhawk Park (2.6 acres)
• Mill Creek Recreation Trail (8.6 acres)

The recreation facilities at MCP help meet the regional and local demands for recreation. As shown in volume 2, recreational demands are projected to increase dramatically into the year 2000. Recreation demands at MCP will also increase. The maintenance and expansion of recreation facilities at MCP will help meet these needs.

a. Rooks Park Management Unit.

(1) Land Classification: Recreation.

(2) Acres: 18.6.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: This is a flat area along Mill Creek Channel.

2. Elevation: 1200 to 1250 (17.7 acres) and 1250 to 1300 (0.9 acre).

3. Aspect (of lake bottom): Flat, 0 to 3 percent (18.3 acres).

4. Percent of Slope: 0 to 3 percent (18.6 acres).

5. Soils: YmA--Yakima silt loam, 0 to 3 percent (18.6 acres).

6. Land Cover/Vegetation: U-S--Upland Shrubs (3.2 acres); R-DT--Riparian Deciduous Trees (5.9 acres); W-OW--Palustrine Open Water (0.2 acre); W-PE--Palustrine Emergent (0.6 acre); UB-L--Irrigated Lawn (5.9 acres); and UB-P--Project Structures/Water Development (2.8 acres).

7. Water Resources: Mill Creek and a pond (a remnant of the original Mill Creek Channel).

8. Wildlife Resources: Bull frogs and songbirds.

9. Fish Resources: None, but the pond has the potential to be a rearing area.

(b) Cultural Factors.

1. Access: Washington State Highway 12, Mill Creek Road, and Rooks Park Road.

2. Utilities: Underground electricity and telephone.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Mill Creek Recreation Trail, Mill Creek Diversion, and Mill Creek Channel.

6. Adjacent Ownership Outside Project: Both private and Walla Walla County (Rooks Park Road).

7. Existing Developments: 35 picnic tables, 1 flush restroom (septic and drainage field), public telephone, metal storage building (278 square feet), drinking water, 54 auto parking slots, charcoal grills, fire rings, kiosk, and an irrigated lawn area with shade trees.

8. Visitor Use: 46,500 (1992) annual visitors for picnicking, swimming, sunbathing, hiking, and trailhead use.

9. Archaeological/Historical Resources:

a. Archaeological. Refer to the Corps Cultural Resource Management Plan.

b. Historical. Located within the Fort Walla Walla Timber Reserve.

(c) Aesthetic Factors.

1. Positive: Rural location, large lawn areas, large old-growth cottonwoods, natural vegetation, the nearby cliff, and Mill Creek offer excellent scenic resources.

2. Negative: The metal storage building and diversion levee impact the area's natural beauty.

(4) Influencing and Constraining Factors. There is only a limited area for expansion. It is the only park outside the city limits of Walla Walla or College Place within 28 miles. Visitation has dramatically increased since the park was opened in the mid-1960's.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE AND ENHANCE INTENSIVE DAY-USE RECREATION AT ROOKS PARK, WITH THE PRIMARY EMPHASIS ON PICNICKING AND TRAIL USE.

2. Protect and enhance the unit's visual resources.

3. Improve the picnicking experience by providing facilities such as a group shelter and additional tables.

4. Provide and improve access for persons with disabilities and the elderly.

(b) Rationale.

1. Rooks Park is one of the best picnicking facilities in the Walla Walla Valley, and is located in close proximity to the city of Walla Walla. It is the only one within 28 miles that has a rural setting. The public expects, and has a right to, an aesthetically-pleasing environment.

2. High visitation and public expectations in visiting public resource areas are the main reasons to protect and enhance the visual resource.

3. Many large groups (businesses and families) are using Rooks Park for picnics. Group shelters are essential for group picnics, especially in the spring and early summer when visitation is at its highest.

4. All persons have a right to enjoy public recreation facilities. Current regulations require universal access for persons with disabilities.

(6) Development and Management Concepts.

• Refer to plate 5-7 for a conceptual development plan for this management unit.
• Monitor and maintain suitable water quality.
• Improve the aesthetics of the area by planting additional trees and shrubs in order to provide a unified appearance, screening, and shade.
• Improve parking.
• Improve fishing and picnicking access for both persons with disabilities and elderly access at the fishing dock.
• Provide interpretive information about the project's operations, ecology, and cultural features.
• Study the potential for providing a rearing area for fish in the old channel (pond).

b. Bennington Lake Recreation Area Management Unit.

(1) Land Classification: Recreation.

(2) Acres: 14.4.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Moderate to steep slopes along Bennington Lake.

2. Elevation: 1205 to 1250 (10.1 acres) and 1250 to 1300 (4.3 acres).

3. Aspect: East (5.6 acres); northeast (2.0 acres); south (2.0 acres); southeast (2.0 acres); southwest (1.9 acres); flat (0.9 acre); and north (0.1 acre).

4. Percent of Slope: 8 to 15 percent (8.3 acres); 16 to 25 percent (1.8 acres); and >25 percent (3.4 acres).

5. Soils: WaD--Walla Walla silt loam, 8- to 30-percent slopes (6.4 acres); Mill Creek Dam (5.4 acres); at the parking area, Bp--Borrow Pit (1.6 acres); and WlB--Walla Walla silt loam, lacustrine substratum, 0 to 8 percent (1.1 acres).

6. Land Cover/Vegetation: U-F--Upland Field (3.8 acres), U-S--Upland Shrub (2.5 acres); U-D--Upland Disturbed (2.7 acres); U-SP--Upland Deciduous Saplings (1.7 acres); R-DT--Riparian Deciduous Trees (0.0006 acre); L-UB--Lacustrine Unconsolidated Bottom (0.4 acre); UB-P--Project Structures/Water Development (0.9 acre); and UB-T--Transportation (2.4 acres).

7. Water Resources: Adjacent to Virgil B. Bennington Lake.

8. Wildlife Resources: Mule deer, songbirds, and California quail.

9. Fish Resources: None. Refer to the Virgil B. Bennington Lake Management Unit.

(b) Cultural Factors.

1. Access: U.S. Highway 12, Tausick Way, Reservoir Road, and Bennington Lake Road.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Mill Creek Dam, Bennington Habitat, Bennington Lake Road, and FWWTR Habitat.

6. Adjacent Ownership Outside Project: No part of this management unit is on the project boundary.

7. Existing Developments: 1 restroom (vault), boat launching ramp (to elevation 1200), parking, gravel parking lot, irrigated lawn, concrete pad, and reservoir elevation gauge (along entrance road).

8. Visitor Use: Fishing, picnicking, boating, and sightseeing.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Virgil B. Bennington Lake; the surrounding views of the project, foothills, and the Blue Mountains.

2. Negative: Exposed mud when the lake level is low.

(4) Influencing and Constraining Factors.

Bennington Lake Recreation Area is the only recreation area adjacent to a lake within 28 miles of the city of Walla Walla. Access to the lake is difficult for elderly and impossible for persons with dissabilities, due to steep topography. Parasites, causing swimmers itch and fecal coliform concentrations, currently hinder the development of a formal swim beach area. State of Washington water quality standards do, however, hold primary contact recreation as a beneficial use of all lakes. Virgil B. Bennington Lake is classified as a lake.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE AND ENHANCE INTENSIVE DAY-USE RECREATION AT BENNINGTON LAKE, WITH THE PRIMARY EMPHASIS ON WATER-ORIENTED RECREATION.

2. Improve the water-oriented experience with provision of facilities such as a group shelter, safe access to the lake, paved parking, and a new boat ramp.

3. Provide access for persons with disabilities and the elderly.

4. Provide visitors with an aesthetically-pleasing environment.

(b) Rationale.

1. Bennington Lake is the only public lake within 28 miles of the city of Walla Walla. This management unit provides the only lake-oriented recreation for the city of Walla Walla and its environs.

2. Recreation facilities have only slightly improved since 1953, when the lake was first filled for recreation. Visitation, however, has increased 500 percent since 1953. For example, the boat ramp is not useable after a 5-foot drop in the lake and, in some drought years, the water does not reach the ramp.

3. Access is extremely difficult and unsafe for the elderly, and impossible for persons confined to wheelchairs. All persons have a right to enjoy public recreation facilities. Current regulations require universal access for persons with disabilities.

4. The public expects, and has a right to, a pleasing aesthetic environment. High visitation and public expectations in visiting public resource areas are the main reasons to protect and enhance the visual.

(6) Development and Management Concepts.

• Refer to plate 5-8 for a conceptual development plan for this management unit.
• Provide safe and universal access to the lake.
• Replace and extend the boat ramp to eliminate safety hazards and property damage.
• Improved picnic facilities, with emphasis on the elderly and persons with disabilities.
• Improved parking.
• Improved water quality.
• Provide public phone.
• Provide swim beach.
• Provide an additional comfort station.
• Provide interpretive information about the operation of the project and its ecological features.

c. Bennington Lake Road Management Unit.

(1) Land Classification: Recreation.

(2) Acres: 24.4.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Rolling hills between Mill Creek floodplain and Prospect Point.

2. Elevation: 1150 to 1200 (4.7 acres); 1200 to 1250 (16.7 acres); and 1250 to 1300 (3.1 acres).

3. Aspect: West (8.8 acres); flat (6.6 acres); southwest (4.7 acres); northwest (2.5 acres); east (0.7 acre); and southeast (0.6 acre).

4. Percent of Slope: 0 to 7 percent (6.6 acres); 8 to 15 percent (9.5 acres); 16 to 25 percent (3.8 acres); and >25 percent (4.5 acres).

5. Soils: WaD--Walla Walla silt loam, 8 to 30 percent (19.9 acres); and YmA--Yakima silt loam, 0 to 3 percent (4.5 acres).

6. Land Cover/Vegetation: U-F--Upland field (11.3 acres); U-S--Upland Shrubs (1.8 acres); U-CT--Upland Coniferous Trees (0.4 acre); U-DT--Upland Deciduous Trees(1.1 acres); R-DT--Riparian Deciduous Trees (0.1 acre); UB-P--Project Structures/Water Development (2.3 acres); and B-T--Urban/Transportation (2.6 acres).

7. Water Resources: Mill Creek Return Canal (intermediate).

8. Wildlife Resources: California quail and songbirds.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: U.S. Highway 12, Tausick Way, Reservoir Road, Bennington Lake Road, and Mill Creek Outlet Canal Road.

2. Utilities: Electric and telephone (aerial).

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Pacific Northwest Bell, 85-48, above-ground communications cable, easement.

5. Adjacent Management Units: Yellowhawk Recreation Area, Mill Creek Office and Information Center, Yellowhawk-Garrison ESA, Fort Walla Walla Timber Reserve Habitat, Bennington Lake Recreation Area, Mill Creek Dam, and Russell Creek Habitat.

6. Adjacent Ownership Outside Project: Walla Walla County and private.

7. Existing Developments: Bennington Lake Road, Second Division Works, Return Canal Service Road (Constitution Path), Mill Creek Return Channel, and associated facilities.

8. Visitor Use: Sightseeing, bicycling, vehicular access to Bennington Lake Recreation Area, and hiking.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: The curvilinear alignment of Bennington Lake Road provides an excellent scenic drive to Virgil B. Bennington Lake.

2. Negative: Above-ground communication cable and telephone poles.

(4) Influencing and Constraining Factors.

Bennington Lake Road is necessary for access to the lake and surrounding lands. The road is used for recreation by both automobiles and bicycles. It was originally constructed for project operations only. Because it is so narrow, there is a potential for conflict between bicyclists and vehicular traffic. This conflict is also a safety hazard.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE AND ENHANCE RECREATIONAL ACCESS TO THE BENNINGTON LAKE RECREATION AREA, AS WELL AS FLOOD CONTROL FOR THE WALLA WALLA VALLEY.

2. Protect and enhance the unit's visual resources.

3. Improve bicycle access to the Bennington Lake Recreation Area Management Unit.

4. Provide a safe environment.

(b) Rationale.

1. Bennington Lake Road provides the only access to Virgil B. Bennington Lake and its surrounding lands. The return canal facilities and access road play an integral part in providing flood control for the Walla Walla Valley.

2. The road has high recreational use. The expectations of the public for recreation include high aesthetic quality.

3. The use of bicycles at MCP has increased dramatically in recent years since MCP's connection to the Mill Creek Recreation Trail. Currently, the road is narrow and no area is designated specifically for bicycle use.

4. The narrow road and scenic alignment are not a safe environment for both automobile and bicycle use.

(6) Development and Management Concepts.

• Refer to plate 5-9 for a conceptual development plan for this management unit.
• Extend the Bennington Lake Trail from the Mill Creek Recreation Trail to Virgil B. Bennington Lake to eliminate conflict between motor vehicles and bicycles.
• Improve aesthetics and safety by placing aerial communication lines underground. Underground lines are current Walla Walla District policy.

d. Yellowhawk Park Management Unit.

(1) Land Classification: Recreation.

(2) Acres: 2.6.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat area along Mill Creek and Yellowhawk Creek.

2. Elevation: 1150 to 1200 (2.6 acres).

3. Aspect: Flat (2.6 acres).

4. Percent of Slope: Flat (2.6 acres).

5. Soils: YmA--Yakima silt loam, 0- to 3-percent slopes (2.6 acres).

6. Land Cover/Vegetation: U-F--Upland Field (0.5 acre); UB-L--Irrigated Lawn (0.9 acre); and UB-P--Project Structures/Water Development (1.1 acres).

7. Water Resources: Adjacent to Mill Creek Channel and Yellowhawk Creek.

8. Wildlife Resources: California quail and songbirds.

9. Fish Resources: Anadromous steelhead passage from Yellowhawk Creek into Mill Creek Channel.

(b) Cultural Factors.

1. Access: U.S. Highway 12, Tausick Way, Reservoir Road, and Bennington Lake Road.

2. Utilities: Electric, telephone, and water.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Pacific Power and Light Company, 104-2, electric line, easement.

5. Adjacent Management Units: Bennington Lake Road and Mill Creek Channel.

6. Adjacent Ownership Outside Project: Walla Walla County/Mill Creek Flood Control Zone District.

7. Existing Developments: Restroom, Project Office, garage/shop building, equipment shed, chemical storage buildings, metal well house, USGS gagehouse, kiosk, parking for eight vehicles, and irrigated lawns and trees.

8. Visitor Use: Picnicking, information, trailhead parking, Project Office, and maintenance facilities.

9. Archaeological/Historical Resources:

a. Archaeological: Refer to the Corps Cultural Resource Management Plan.

b. Historical: The Project Office and garage are over 50 years old. They were constructed in 1942, as a field office and garage, by the Corps, Bonneville District, Oregon.

(c) Aesthetic Factors.

1. Positive: The management unit's large shade trees and lawn provide a positive visual environment.

2. Negative: The management unit has the worst scenic quality on MCP. The high chain-link security fence around the office gives the building a correctional-type atmosphere. The office and maintenance buildings are in need of upkeep. The storage yard is next to the creek and can be seen from the highly-visited Mill Creek Recreational Trail.

(4) Influencing and Constraining Factors.

Other than Rooks Park, this area provides the only picnic area along Mill Creek, and the only one along Yellowhawk Creek or the south side of Mill Creek. The office and storage facilities do not meet current codes.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE AND ENHANCE INTENSIVE DAY-USE RECREATION AT YELLOWHAWK PARK, WITH THE PRIMARY EMPHASIS ON PICNICKING AND ENVIRONMENTAL STUDY.

2. Protect and enhance the unit's visual resources. 3. Improve the picnicking experience by providing facilities such as additional lawn area, picnic tables, and shade trees.

(b) Rationale.

1. Yellowhawk Recreation Area is the only area in the Walla Walla Valley with access to Mill Creek except Rooks Park. This site is undeveloped, and currently provides the area for the Project Office and maintenance facilities and trailhead. These facilities can be located in nearby units better suited for these activities.

2. The public expects high scenic quality at recreation facilities. Also, the appearance of public facilities represents the quality of the operating agency.

3. The site is extremely undeveloped for picnicking and day use, and can help provide day use for existing demand and future needs.

(6) Development and Management Concepts.

• Refer to plate 5-10 for a conceptual development plan for this management unit.
• Redesign area for safety and efficiency.
• Provide additional picnic facilities.
• Provide more parking.
• Provide interpretive information about the project operations and ecological and cultural features.
• Improve aesthetics by adding more trees and shrubs.

e. Mill Creek Recreation Trail Management Unit.

(1) Land Classification: Recreation.

(2) Acres: 8.6.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat area along the north side of Mill Creek Channel.

2. Elevation: 1150 to 1200 (4.8 acres) and 1200 to 1250 (3.8 acres).

3. Orientation: Flat, 0 to 3 percent (8.6 acres).

4. Percent of Slope: 0 to 3 percent (8.6 acres).

5. Soils: YmA--Yakima silt loam, 0 to 3 percent (8.6 acres).

6. Land Cover/Vegetation: U-S--Upland Shrubs (5.4 acres) and UB-P--Project Structures/Water Development (3.2 acres).

7. Water Resources: Adjacent to Mill Creek Channel.

8. Wildlife Resources: Deer and songbirds.

9. Fish Resources: See adjacent unit, Mill Creek Channel.

(b) Cultural Factors.

1. Access: Mill Creek Recreation Trail, Rooks Park Road, Reservoir Road, and South Mill Creek Trail.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Mill Creek Channel and Rooks Park.

6. Adjacent Ownership Outside Project: State of Washington (Walla Walla Community College) and private.

7. Existing Developments: Paved trail and 1 picnic table.

8. Visitor Use: Running, bicycling, walking, fishing, picnicking, and sightseeing.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Mill Creek, riparian vegetation, and a view of the cliffs.

2. Negative: The unnatural appearance of Mill Creek Channel, and views of the Mill Creek maintenance area.

(4) Influencing and Constraining Factors. Mill Creek Trail is part of the city and county of Walla Walla's trail system. Visitor use has increased significantly since the trail was constructed. This trail will be part of the proposed Walla Walla Trail. The Mill Creek Recreation Trail provides paved access to Mill Creek.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE, MAINTAIN, AND ENHANCE INTENSIVE RECREATION USE. EMPHASIS ON NON-MOTORIZED TRAIL USE.

2. Provide and enhance the unit's visual resources.

3. Continue to work with city/county.

4. Provide access for persons with disabilities and the elderly.

(b) Rationale.

1. The trail is an important recreation resource in the Walla Walla Valley and the trail system. Visitation has continued to increase since the trail's placement.

2. The public expects, and has a right to, a pleasing aesthetic environment. The storage site should be relocated to the new Mill Creek Office and Information Management Unit.

3. The trail is part of the city and county trail system. It is also a portion of the proposed Walla Walla Trail.

4. Access to Mill Creek is not possible for either persons with disabilities or elderly people. All persons have the right to enjoy public recreation facilities. Current regulations require universal access.

(6) Development and Management Concepts.

• Refer to plate 5-11 for a conceptual development plan for this management unit.
• Develop interpretive information facilities.
• Provide accessibility to Mill Creek for persons with disabilities and the elderly.
• Improve picnicking facilities.

5.04. Mitigation.

One management unit, the Fort Walla Walla Timber Reserve (FWWTR) (61.8 acres), falls under the land classification of Mitigation. This management unit was purchased to help compensate for wildlife haibtat losses due to the four Snake River dams.

a. Fort Walla Walla Timber Reserve Habitat Management Unit.

(1) Land Classification: Mitigation.

(2) Acres: 61.8.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Moderate slopes with gentle swells.

2. Elevation: 1365 (highest point on MCP); 1200 to 1250 (2.9 acres); 1250 to 1300 (27.9 acres); 1300 to 1350 (28.4 acres); and 1350+ (2.5 acres).

3. Aspect: Flat (7.4 acres); north (3.0 acres); east (11.1 acres); southeast (12.3 acres); south (6.7 acres); southwest (12.7 acres); west (1.9 acres); and northwest (3.1 acres).

4. Percent of Slope: 0 to 7 percent (7.4 acres); 8 to 15 percent (37.9 acres); 16 to 25 percent (14.24 acres); and >25 percent (2.3 acres).

5. Soils: WaD--Walla Walla silt loam, 8 to 30 percent (61.8 acres).

6. Land Cover/Vegetation: A-C--Agricultural Cropland (60.8 acres) recently planted with grasses; and U-F--Upland Field (1.1 acres).

7. Water Resources: None.

8. Wildlife Resources: Whitetail deer, mule deer, songbirds, pheasants, waterfowl, and California quail.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: Bennington Lake Road and East Service Road.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Bennington Lake Road, Bennington Lake Recreation Area, Bennington Habitat, and South Mill Creek Recreation Trail.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: None.

8. Visitor Use: Hiking and hunting (in the future).

9. Archaeological/Historical Resources:

a. Archaeological. Refer to the Corps Cultural Resource Management Plan.

b. Historical. Water reservoir for Walla Walla Air Base in the 1940's (covered with earth in the 1980's).

(c) Aesthetic Factors.

1. Positive: The management unit is along the top of a bluff that provides excellent views of Mill Creek, the Walla Walla Valley, and the Blue Mountains.

2. Negative: The management unit is currently undeveloped, and does not provide adequate visual diversity.

(4) Influencing and Constraining Factors.

This management unit was purchased under the Lower Snake River Fish and Wildlife Compensation Plan to mitigate for habitat losses due to the construction of the four lower Snake River dams. The available soil depth, within the Walla Walla silt loam, is more than adequate to allow adequate plant root penetration. The management unit is shaped like an hour glass connected by a narrow corridor, which may be a hindrance to the management of the unit.

(5) Resource Objectives.

(a) Objective. DEVELOP AND OPERATE THE AREA IN A MANNER THAT MEETS THE MANDATED WILDLIFE MITIGATION AND UTILIZATION GOALS OF THE LOWER SNAKE RIVER FISH AND WILDLIFE COMPENSATION PLAN.

(b) Rationale. This property was one of many purchased as a part of the Lower Snake River Fish and Wildlife Compensation Plan. This mandates that the land be utilized to support the goals of the program. These goals are to develop wildlife habitat, both to obtain mitigation crediting for lost habitat and to provide public hunting to offset wildlife and hunting losses caused by the construction of the Lower Snake River Projects.

(6) Development and Management Concepts. Refer to plate 5-16 for a conceptual development plan for this management unit.

(a) Wildlife Habitat Development.

1. Four shrub-tree areas will be developed.

2. Two wildlife watering sites will be developed.

3. Two dry-land wildlife food plots will be established.

4. Perennial grass cover will be established on the remainder of the site.

(b) Project Operations. Monument and fence boundaries.

(c) Public Hunting Access.

1. Hunting will be allowed when adequate habitat is developed.

2. Hunting weapons will be restricted to archery equipment and shotguns.

3. Public informational signs will be installed to advise both hunters and non-hunters of the seasons when the area is accessible to hunters.

4. The area near the Bennington Lake Recreation Management Unit may be closed to hunting due to its close proximity to the Bennington Lake Recreation Management Unit.

5.05. The ESA's

Two management areas are classified as Environmentally Sensitive Areas (ESA). These areas are important to the operation of the project, but are sensitive and are restricted to minimal development. These areas are:

• Mill Creek ESA (42.3 acres)

• Yellowhawk-Garrison Creek ESA (2.0 acres)

a. Mill Creek ESA Management Unit.

(1) Land Classification: Environmentally Sensitive Area.

(2) Acres: 42.3.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat along Mill Creek and the wetlands created by Diversion Dam, with steep slopes on the bluff.

2. Elevation: 1250 to 1300 (38.7 acres); 1300 to 1350 (2.9 acres); and 1350 to 1400 (0.6 acre).

3. Orientation:

a. Wetlands: Flat, 0 to 3 percent (38.0 acres).

b. Cliff: North (3.2 acres); northeast (0.1 acre); and west (0.9 acre).

4. Percent of Slope:

a. Wetlands: 0 to 3 percent (38.0 acres).

b. Cliff: 8 to 15 percent (0.5 acre); 16 to 25 (0.5 acre); and >25 percent (3.4 acres).

5. Soils:

a. Wetlands: YmA--Yakima silt loam, 0- to 3-percent slopes (37.6 acres).

b. Cliff Area: AtE2--Athena silt loam, 30- to 45-percent slopes (4.7 acres).

6. Land Cover/Vegetation:

a. Land Cover: W-OW--Palustrine Open Water (1.4 acres); W-PE--Palustrine Emergent (12.7 acres); W-PS--Palustrine Scrub Shrub (10.1 acres); W-PF--Palustrine Forest (9.9 acres); U-F--Upland Field (2.7 acres); and U-S--Upland Shrub (5.5 acres).

b. Vegetation: Ponderosa pine, black cottonwood, Rocky Mountain maple, water birch, red-osier dogwood, Douglas hawthorn, Saskatoon service berry, bittercherry, common chokecherry, golden currant, and Wood's rose.

7. Water Resources: Mill Creek.

8. Wildlife Resources: Golden and bald eagles, mule deer, coyote, songbirds, and chukar.

9. Fish Resources: Anadromous steelhead, resident rainbow trout, sculpin, forage fish, and possibly bull trout.

(b) Cultural Factors.

1. Access: A limited project road along the Diversion Levee allows access to the management unit.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Mill Creek Diversion and Bennington Habitat.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: East end of the first debris barrier.

8. Visitor Use: Limited hiking and viewing.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Wetlands, riparian vegetation along Mill Creek, and steep slopes provide visual diversity.

2. Negative: The debris barrier is the only manmade object in the management unit.

(4) Influencing and Constraining Factors.

(a) Wetlands: Wetlands are protected under Section 404 of the Clean Water Act. Any disturbance must be approved through a permit. These wetlands provide biodiversity for fish and wildlife, as well as aesthetic values.

(b) Cliffs: Steep topography, highly erodible soils, and no available utilities.

(5) Resource Objectives.

(a) Resource Objectives.

1. PROTECT WETLANDS AND STEEP CLIFF AREA AND THEIR ASSOCIATED FISH AND WILDLIFE RESOURCES.

2. Minimize development.

(b) Rationale. The components of the wetland, open water, and steep cliff habitat, in association with the increased complexity of vegetation, provide the greatest diversity in fish and wildlife species of any habitat available in over a 40-mile radius. The management unit is extremely sensitive to development, and is not scheduled for development. Any developments that do occur should be very minimal.

(6) Development and Management Concepts.

• Refer to plate 5-13 for a conceptual development plan for this management unit.
• Provide interpretive information on the management unit's role in the operation of the project and the area's ecology.
• Remove the debris disposal area.

b. Yellowhawk-Garrison ESA Management Unit.

(1) Land Classification: Environmentally Sensitive Area

(2) Acres: 2.0.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Stream corridor between Yellowhawk and Garrison Creeks.

2. Elevation: 1150 to 1200 (2.0 acres).

3. Orientation: Flat (2.0 acres).

4. Percent of Slope:Flat, 0 to 3 percent (2.0 acres).

5. Soils: YmA--Yakima silt loam, 0- to 3-percent slopes (2.0 acres).

6. Land Cover/Vegetation:

a. Land Cover: U-F--Upland Field (0.02 acre) and R-DT--Riparian Deciduous Trees 91.98 acres).

b. Vegetation: Rocky Mountain maple, water birch, red-osier dogwood, Douglas hawthorn, Saskatoon service berry, bittercherry, common chokecherry, golden currant, and Wood's rose.

7. Water Resources: Yellowhawk and Garrison Creeks.

8. Wildlife Resources: Pheasant, quail, Hungarian partridge, and songbirds.

9. Fish Resources: Anadromous steelhead, resident rainbow trout, sculpin, and forage fish.

(b) Cultural Factors. 1. Access: None within the management unit. Bennington Lake Road is within 30 feet of the western management unit boundary.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: None.

5. Adjacent Management Units: Bennington Lake Road.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Partially fenced boundary.

8. Visitor Use: Sightseeing with very limited access.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Riparian vegetation and Yellowhawk Creek provide high scenic quality.

2. Negative: None.

(4) Influencing and Constraining Factors. Riparian and wetland vegetation, and highly erodible soils.

(5) Resource Objectives.

(a) Resource Objectives.

1. PROTECT AND MAINTAIN CHANNELS IN AS NATURAL OF STATE AS POSSIBLE WITHIN THE MANAGEMENT UNIT SO WATER FLOWS CAN PASS FOR IRRIGATION.

2. Provide safe and efficient passage for anadromous fish.

3. Maintain suitable riparian and wetland vegetation along the channel.

(b) Rationale.

1. The Corps, as a "good neighbor policy," transfers water to Yellowhawk and Garrison Creeks for irrigation.

2. Viability of anadromous fish stocks are important for the local community and the region. Yellowhawk and Garrison Creeks become critical passage corridors for migrating steelhead when there is not sufficient water in Mill Creek below the Division Point (where flows are diverted for irrigation), and water quality conditions on Mill Creek below the city of Walla Walla become unacceptable for fish health and migrational cues.

3. Riparian and wetland vegetation provide erosion control and fish and wildlife habitat, especially for anadromous fish.

(6) Development and Management Concepts.

• Refer to plate 5-14 for a conceptual development plan for this management unit.
• Fenced boundary.

5.06. Multiple Resource Management--Recreation, Low Density

One management unit is classified as Multiple Resource Management--Recreation, Low Density:

• South Mill Creek Trail (24.0 acres).

This management unit is managed for multiple uses, but especially low-density recreation. This management unit also provides wildlife habitat and access to project operations.

a. South Mill Creek Trail Management Unit.

(1) Land Classification: Multiple Resource Management--Recreation, Low Density.

(2) Acres: 24.0.

(3) Unit Description:

(a) Ecological Factors.

1. Landform:

a. Creek Area: Flat area parallel to, and south of, Mill Creek Channel between Diversion Dam and Division Dam.

b. Cliff Area: Steep hillside.

2. Elevation: 1150 to 1200 (3.7 acres); 1200 to 1250 (10.8 acres); 1250 to 1300 (3.9 acres); 1300 to 1350 (5.1 acres); and 1350+ (0.3 acre).

3. Orientation:

a. Creek Area: Flat (14.5 acres).

b. Cliff Area: North (9.0 acres) and east (0.2 acre).

4. Percent of Slope:

a. Creek Area: 0 to 7 percent (14.5 acres).

b. Cliff Area: 8 to 15 percent (0.8 acre); 16 to 25 percent (0.2 acre); and >25 percent (8.5 acres).

5. Soils:

a. Creek Area: YkA--Yakima gravelly silt loam, 0- to 3-percent slopes (16.0 acres) and YmA--Yakima silt loam, 0- to 3-percent slopes (1.4 acres).

b. Cliff Area: AtE2--Athena silt loam, 30- to 45-percent slope, eroded (6.6 acres).

6. Land Cover/Vegetation:

a. Land Cover: U-F--Upland Field (7.9 acres); U-S--Upland Shrubs (9.9 acres); R-S--Riparian Shrub (0.4 acre); R-DT--Riparian Deciduous Trees (1.1 acres); and UB-P--Project Structures/Water Development (4.6 acres).

b. Vegetation: Black cottonwood, Rocky Mountain maple, water birch, red-osier dogwood, Douglas hawthorn, Saskatoon service berry, bittercherry, common chokecherry, antelope bitterbrush, golden currant, and Wood's rose.

7. Water Resources: Mill Creek and the irrigation channel.

8. Wildlife Resources: Mule deer, songbirds, chukar, and quail.

(b) Cultural Factors.

1. Access: Bennington Lake Road, and the footbridge across Mill Creek from Rooks Park and Mill Creek Recreation Trail.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Pacific Power and Light Company, 67-17 electric line easement; and Mark Klicker, 2-90-29 access road and easement.

5. Adjacent Management Units: Mill Creek Channel, Mill Creek Diversion, Bennington Lake Road, Mill Creek Office and Information, and FWWTR Habitat.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Gravel trail (South Levee Service Road), primitive horse trailer unloading area, and primitive group camping area.

8. Visitor Use: Equestrian, birdwatching, sightseeing, hiking, and primitive group camping.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Mill Creek, riparian vegetation, large cottonwood trees, and the cliffs covered with native vegetation.

2. Negative: View of adjacent land uses, and the view of the manmade channel for Mill Creek.

(4) Influencing and Constraining Factors.

The management unit provides access to the equestrian trails in the Bennington Habitat Management Unit and the Russell Creek Habitat Management Unit. The area for the group camp is the only area on MCP suitable for group camping, which can be done only by special permit. Sanitation facilities are not provided at the group camping area.

(5) Resource Objectives.

(a) Resource Objectives.

1. CONTINUE TO PROVIDE AND ENHANCE SOUTH MILL CREEK TRAIL AS A LOW-DENSITY RECREATION AREA, WITH THE MAIN EMPHASIS ON THE TRAIL AND PRIMITIVE CAMPING.

2. Provide an aesthetically-pleasing environment.

3. Manage and improve the food source for young upland game birds.

4. Provide access for shoreline fishing for everyone.

(b) Rationale.

1. This management unit provides gravel trail access to the Bennington Lake Habitat Management Unit. The Bennington Lake Habitat Management Unit is excellent for equestrian activities, which are extremely popular throughout the Walla Walla Valley. The small group camping area is the only location suitable for primitive camping at MCP.

2. The public expects, and has a right to, an aesthetically-pleasing environment. The adjacent land uses have a negative visual impact near Bennington Lake Road.

3. This riparian corridor provides important wildlife habitat for local species, including upland gamebirds. The access to water is critical for many species and, therefore, provides wildlife observation and hunting on the adjacent habitat management units.

4. Access to Mill Creek provides important water-oriented recreational opportunities for the public. Access to the channel is difficult for all persons, especially for the elderly and for persons with disabilities.

(6) Development and Management Concepts.

• Refer to plate 5-15 for a conceptual development plan for this management unit.
• Connect Mill Creek Recreation trail to Bennington Lake Trail.
• Berm and screen the adjacent visual impacts.
• End vehicular access over First Diversion facilities.
• Improve horse trailer parking.
• Connect South Levee Road to Bennington Lake Road.

5.07. Multiple Resource Management--Wildlife Management General.

Two management units are classified as Multiple Resource Management--Wildlife Management General. These management units total 306.0 acres, and comprise approximately half of the MCP fee lands.

• Bennington Habitat Management Unit (208.4 acres).

• Russell Creek Habitat Management Unit (97.6 acres).

These management units are managed for multiple resources, especially wildlife habitat. They provide low density recreation, as well as areas or facilities used for flood control.

a. Bennington Habitat Management Unit.

(1) Land Classification: Multiple Resource Management--Wildlife Management General

(2) Acres: 208.4.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Moderate slopes surrounding the north and south of Virgil B. Bennington Lake.

2. Elevation: 1200 to 1250 (97.6 acres); 1250 to 1300 (106.1 acres); 1300 to 1350 (4.6 acres); and 1300+ (0.1 acre).

3. Orientation: Flat (68.0 acres); north (9.8 acres); northeast (8.5 acres); east (17.4 acres); southeast (22.5 acres); south (11.8 acres); southwest (22.6 acres); west (30.3 acres); and northwest (23.5 acres).

4. Percent of Slope: 0 to 7 percent (67.9 acres); 8 to 15 percent (83.6 acres); 16 to 25 percent (43.3 acres); 25 percent (13.7 acres).

5. Soils: WaD--Walla Walla silt loam, 8 to 30 percent (136.8 acres); Bp--Borrow Pits (2.1 acres); WaB--Walla Walla silt loam, 0 to 8 percent (28.9 acres); Mill Creek Dam (2.0 acres); WlB--Walla Walla silt loam, lacustrine substratum, 0 to 8 percent (7.2 acres); WlD--Walla Walla silt loam, lacustrine substratum, 8 to 30 percent (1.4 percent); and AtE2--Athena silt loam, 30 to 45 percent (0.2 acre).

6. Land Cover/Vegetation: U-F--Upland Field (139.9 acres); U-S--Upland Shrub (15.5 acres); U-SP--Upland Deciduous Saplings (5.1 acres); U-DT--Upland Deciduous Trees (5.69 acres); U-D--Upland Disturbed (12.6 acres); R-F--Riparian Field (11.8 acres); R-S--Riparian Shrubs (10.6 acres); R-DT--Riparian Deciduous Tress (6.4 acres); L-UB--Lacustrine Unconsolidated Bottom (0.12 acre); and UB-P--Project Structures/Water Development (0.86 acre).

7. Water Resources: The intake stream to Virgil B. Bennington Lake.

8. Wildlife Resources: Whitetail deer, mule deer, songbirds, pheasants, water fowl, and California quail.

9. Fish Resources: None (refer to Virgil B. Bennington Lake Management Unit).

(b) Cultural Factors.

1. Access: Bennington Lake Road, South Mill Creek Trail, Upper Service Road, East Service Road, Farm Spur Number 1, and Farm Spur Number 2.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Howard A. Hughes, 104-5: access road easement.

5. Adjacent Management Units: Mill Creek Dam, Bennington Lake Recreation Area, FWWTR Habitat, Mill Creek Diversion, and Russell Creek Habitat.

6. Adjacent Ownership Outside Project: Private (see volume 2, section 3, plate 3-10).

7. Existing Developments: Dirt access roads, 1950's wildlife habitat development by WDW, 1980's wildlife development (shrub and tree plantings, pastures, and food plots) by the Corps.

8. Visitor Use: Hunting, birdwatching, equestrian, hiking, fishing, and sightseeing.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: The rural character of the entire management unit, as well as excellent vistas. The abundance of songbirds provides excellent auditory resources for the public.

2. Negative: Straight-row, orchard-type tree and shrub plantings do not fit into the rural setting.

(4) Influencing and Constraining Factors. The management unit is necessary for temporarily holding floodwaters to protect the city of Walla Walla and its environs. The management unit also provides important habitat for local wildlife populations, as well as being an important area for recreation activities (i.e., hunting and hiking). The major soil in the management unit, WaD, is an excellent soil for wildlife habitat developments. Precipitation is marginal for non-irrigated plantings, but is adequate for habitat development. The adjacent lake riparian shore vegetation and tree and shrub plantings provide excellent habitat diversity to the management unit.

(5) Resource Objectives.

(a) Objectives.

1. PROTECT AND MANAGE THE UNIT'S HABITAT FOR LOCAL WILDLIFE SPECIES.

2. Manage the unit for flood control.

3. Manage the unit for upland game-bird habitat.

4. Manage the unit for nesting songbird habitat.

5. Manage the unit as a resting and wintering habitat for migratory birds.

6. Manage the unit for low density recreation, with the main emphasis on wildlife-oriented and trail-oriented recreation.

7. Manage habitat development plantings to improve and protect the visual quality of the unit.

(b) Rationale.

1. The MCP lands support several species of wildlife that provide recreation for numerous visitors each year. Managing for wildlife-based habitat will help maintain populations that will continue to provide recreational opportunities for visitors.

2. Bennington Habitat Management Unit serves as an area where floodwaters from Mill Creek can be stored. Flood storage waters can cover almost the entire management unit at elevation 1270 (see volume 2, plate 3-15).

3. The MCP has provided important wildlife habitat for several species of upland gamebirds since the 1950's. These species provide hunting and wildlife observation recreation for the public. The MCP contains the only public lands large enough in acreage to support these types of low density recreation.

4. Over 76 species of songbirds have been observed on MCP, and the Bennington Habitat Management Unit provides important songbird habitat. The auditory and visual resources are enhanced due to the presence of passerines.

5. The area around Virgil B. Bennington Lake provides both a resting and wintering habitat for migratory birds.

6. In addition to providing wildlife-based recreation opportunities, this management unit provides other types of low density recreation (i.e., hiking, mountain bicycling, and horseback riding). The ability to provide these types of recreational activities so close to the city of Walla Walla is an asset to the entire Walla Walla Valley.

7. The older plantings (1950's) have been planted in straight rows. During the recreation season, the orchard-type plantings are visibly noticeable in a generally natural-appearing landscape.

(6) Developement and Management Concepts.

• Refer to plate 5-16 for a conceptual development plan for this management unit.
• Manage and improve the availability and functional usefulness of wildlife habitat.
• Continue to provide travel corridors and cover for escape, resting, reproduction, and thermal juvenile rearing and feeding.
• Enhance the 1950;s WDW plantings to improve habitat and visual quality.
• Adjust access road easement onto existing roads.

b. Russell Creek Habitat Management Unit.

(1) Land Classification: Multiple Resource Management, Wildlife Management General.

(2) Acres: 97.6.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: A "V"-shaped drainage below Mill Creek Dam and Russell Creek floodplain.

2. Elevation: 1100 to 1150 (22.4 acres); 1150 to 1200 (33.5 acres); 1200 to 1250 (33.9 acres); and 1250 to 1300 (7.8 acres).

3. Orientation: Flat (32.4 acres); north (0.3 acre); east (4.0 acres); southeast (15.3 acres); south (0.9 acre); southwest (4.6 acres); west (25.7 acres); and northwest (14.5 acres).

4. Percent of Slope: 0 to 7 percent (32.4 acres); 8 to 15 percent (36.7 acres); 16 to 25 percent (25.8 acres); and >25 percent (2.7 acres).

5. Soils: WaD--Walla Walla silt loam, 8 to 30 percent (75.1 acres); and WaB--Walla Walla silt loam, 0 to 8 percent (22.5 acres).

6. Land Cover/Vegetation: U-F--Upland Field (85.2 acres); U-S--Upland Shrub (0.7 acre); U-DT--Upland Deciduous Trees (9.3 acres); and UB-P--Project Structures/Water Development (2.4 acres).

7. Water Resources: Russell Creek Canal (emergency use only).

8. Wildlife Resources: White-tailed deer, mule deer, songbirds, pheasants, and California quail.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: Bennington Lake Road, Return Canal Service Road, Russell Creek Canal Road, and East Service Road.

2. Utilities: None.

3. Land Ownership/Management: U.S. Government/Corps of Engineers.

4. Outgrants: Howard A. Hughes, 104-5, access road, easement.

5. Adjacent Management Units: Bennington Lake Road, Mill Creek Dam, and Bennington Habitat.

6. Adjacent Ownership Outside Project: Private (see volume 2, section 3, plate 3-10).

7. Existing Developments:

a. Project Structures: Russell Creek Canal, lower valvehouse, upper valvehouse, and Mill Creek Return Canal.

b. Wildlife Habitat: Two gallinaceous guzzlers, tree and shrub plantings (along Russell Creek Canal, by WDW in the 1950's; and six tree and shrub areas planted in the 1980's by the Corps), pasture (7.3 acres), and food plots.

8. Visitor Use: Hunting, birdwatching, hiking, and sightseeing.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: The management unit provides sharp contrast to the surrounding agricultural fields and Mill Creek Dam. The Blue Mountains are visible from the southeast-facing slopes. The management unit is entirely visible from the top of Mill Creek Dam.

2. Negative: The straight axis of Russell Creek Outlet Canal and the wildlife plantings that parallel the canal in straight-row plantings are a dominant manmade feature in an otherwise natural-appearing landscape.

(4) Influencing and Constraining Factors. The outlet canals are used during flood control operations. Russell Creek Canal is only used when the Mill Creek Return Canal is insufficient. This management unit provides important habitat for local wildlife populations, as well as an important area for recreation activities (i.e., hunting and hiking). The major soil, WaD, is an excellent soil for wildlife habitat development.

(5) Resource Objectives.

(a) Objectives.

1. PROTECT AND MANAGE THE UNIT'S HABITAT FOR LOCAL WILDLIFE SPECIES.

2. Manage the unit for flood control facilities, as required.

3. Manage the unit for upland gamebird habitat.

4. Manage the unit for low-density recreation, with the main emphasis on wildlife-oriented recreation.

5. Manage habitat development plantings to improve and protect the visual quality of the management unit.

(b) Rationale.

1. The MCP lands support several species of wildlife that provide recreation for numerous visitors each year. Managing for habitat will help maintain populations that will continue to provide wildlife-based recreational opportunities for visitors.

2. Russell Creek Habitat Management Unit contains important outlet facilities for floodwaters held behind Mill Creek Dam. These facilities are important in maintaining flood control for the city of Walla Walla and the safety of Mill Creek Dam.

3. The MCP has provided important wildlife habitat for several species of upland gamebirds since the 1950's. These species provide hunting and wildlife observation recreation for the public. The MCP contains the only public lands large enough in acreage to support these types of low density recreation.

(6) Development and Management Concepts.

• Refer to plate 5-17 for the conceptual development plan for the Russell Creek Habitat Management Unit.
• Manage and improve the availability and functional usefulness of wildlife habitat.
• Continue to provide travel corridors and cover for escape, resting, reproduction, and thermal juvenile rearing and feeding.
• Enhance the 1950 WDW plantings to improve habitat and visual quality.

5.08. Easement Lands.

Three management units, totaling 87.3 acres, are classified as Easement Lands:

• Rooks Park Road (2.5 acres).

• Russell Creek Outlet Canal (11.5 acres).

• Russell Creek Flowage (73.3 acres).

The Corps administers certain easement son these management units that are necessary for the operation and maintenance of MCP.

a. Rooks Park Management Unit.

(1) Land Classification: Easement lands.

(2) Acres: 2.5.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat area in the Mill Creek floodplain.

2. Elevation: 1250 to 1300 (2.5 acres).

3. Orientation: Flat (2.5 acres).

4. Percent of Slope: 0 to 7 percent (2.5 acres).

5. Soils: YKA--Yakima gravelly silt loam,0 to 3 percent (1.8 acres); and YmA--Yakima silt loam, 0 to 3 percent (0.7 acres).

6. Land Cover/Vegetation: U-F--Upland Filed (1.4 acres); U-DT--Upland Deciduous Trees (0.2 acre); and UB-T-Urban Transportation (0.9 acre).

7. Water Resources: None

8. Wildlife Resources: California quail and pheasants.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: Mill Creek Road.

2. Utilities: Electric and telephone.

3. Land Ownership/Management: Walla Walla County.

4. Outgrants: Corps of Engineers access for the operation and maintenance of MCP.

5. Adjacent Management Units: Rooks Park.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Entrance road between Mill Creek Road and Rooks Park.

8. Visitor Use: Access to Rooks Park and parking when the park gate is closed during the fall and winter months.

a. Archaeological/Historical Refer to the CENPW Culture Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Adjacent rural landscapes.

2. Negative: Edge of the road is rough, and could be maintained to give the public a better entrance eperience to Rooks Park.

(4) Influencing and Constraining Factors. None.

(5) Resource Objectives.

(a) Objective:

1. (a) Objective CONTINUE TO RETAIN ACCESS RIGHTS FOR THE OPERATION AND MAINTENANCE OF MCP.

(b) Rationale. The Crops conveyed this management to Walla

Walla County, but needed the land as access to the project for operation and

maintenance pupose. This management unit also provides public access to Rooks Park.

(6) Development and Management Concepts.

• Refer to plate 5-18 for a conceptual development plan for Rooks Park Road Management Unit.
• Explore options with Walla Walla County to improve the appearance of the area between the road and the adjacent properties.

b. Russell Creek Canal Management Unit.

(1) Land Classification: Easement lands.

(2) Acres: 11.5.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat.

2. Elevation: 1050 to 1100 (6.9 acres) and 1100 to 1150 (4.6 acres).

3. Orientation: Flat (11.5 acres).

4. Percent of Slope: 0 to 7 percent (11.5 acres).

5. Soils: CaA--Catherine silt loam, 0- to 3-percent slopes (5.2 acres); and OnA--Onyx silt loam, 0- to 3-percent slopes (6.4 acres).

6. Land Cover/Vegetation: U-DT--Upland Deciduous Trees (0.2 acre); R-DT--Riparian Deciduous Trees (0.3 acre); A-C--Agricultural Cropland (11.0 acres); and UB-T--Urban/Transportation (0.06 acre).

7. Water Resources: The canal, when floodwaters are passed to Russell Creek.

8. Wildlife Resources: Mule deer and pheasants.

9. Fish Resources: None.

(b) Cultural Factors.

1. Access: Tausick Way, Reservoir Road, Bennington Lake road, Ease Service Road, Russell Creek Road (county), and Russell Creek Canal Road (Corps).

2. Utilities: None.

3. Land Ownership/Management: Private.

4. Outgrants: Dodey, bridge reservation; Walla Walla County, bridge reservation; and Jones, bridge reservation.

5. Adjacent Management Units: Russell Creek Habitat and Russell Creek Flowage.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Russell Creek Outlet Canal (250 cfs capacity).

8. Visitor Use: None.

9. Archaeological/Historical Resources: Refer to the CENPW Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: The low profile of the canal is not visible from the ground level, except at the point where Russell Creek Road crosses the canal.

2. Negative: None.

(4) Influencing and Constraining Factors. This management unit is needed by the Corps for flood control operations. The canal is used for emergency water release from Virgil B. Bennington Lake when the Mill Creek Return Canal is inoperable or at capacity.

(5) Resource Objectives.

(a) Objectives. CONTINUE TO MAINTAIN AND MANAGE THE MANAGEMENT UNIT FOR THE RELEASE OF FLOODWATERS FROM VIRGIL B. BENNINGTON LAKE.

(b) Rationale. The management unit is important to maintaining flood control for the Walla Walla Valley.

(6) Development and Management Concepts. Refer to plate 5-19 for the conceptual development plan for the Russell Creek Canal Management Unit.

c. Russell Creek Flowage Management Unit.

(1) Land Classification: Easement Lands.

(2) Acres: 73.3.

(3) Unit Description:

(a) Ecological Factors.

1. Landform: Flat area along Russell Creek.

2. Elevation: 1050 to 1100 (72.6 acres) and 1100 to 1150 (0.7 acres).

3. Orientation: Flat (69.5 acres); southeast (0.7 acre); south (2.7 acres); and southwest (0.3 acre).

4. Percent of Slope: 0 to 7 percent (69.5 acres); 8 to 15 percent (3.3 acres); 16 to 25 percent (0.5 acre); and >25 percent (0.006 acre).

5. Soils: CaA--Catherine silt loam, 0- to 3-percent slope (64.8 acres); WaD--Walla Walla silt loam, 8 to 30 percent (5.0 acres); and OnA--Onyx silt loam, 0- to 3-percent slopes (3.5 acres).

6. Land Cover/Vegetation: R-DT--Riparian Deciduous Trees (0.4 acre); L-OW--Lacustrine Open Water (0.2 acre); A-C--Agricultural Cropland (72.1 acres); and UB-T--Urban/Transportation (0.5 acre).

7. Water Resources: Russell Creek and canal. Regulated intermittent flow from Bennington Lake, used in emergency situations only.

8. Wildlife Resources: Mule deer, pheasants, and California quail.

9. Fish Resources: Russell Creek: rainbow trout and sculpins.

(b) Cultural Factors.

1. Access: Russell Creek Road (county).

2. Utilities: None.

3. Land Ownership/Management: Private.

4. Outgrants: None.

5. Adjacent Management Units: Russell Creek Canal.

6. Adjacent Ownership Outside Project: Private.

7. Existing Developments: Agricultural cropland.

8. Visitor Use: None.

9. Archaeological/Historical Resources: Refer to the Corps Cultural Resource Management Plan.

(c) Aesthetic Factors.

1. Positive: Undeveloped agricultural cropland and a surrounding view of the rural area.

2. Negative: None.

(4) Influencing and Constraining Factors. This management unit was purchased by the Corps because flooding in this area caused by floodwaters released to Russell Creek through the Russell Creek Canal. The Russell Creek Canal is only used in emergencies due to the flooding it creates along the creek. The Mill Creek Return Canal allows water to be drawn to lake elevation 1210. Russell Creek Canal can draw the lake down to elevation 1187.

(5) Resource Objectives.

(a) Resource Objectives. CONTINUE TO RETAIN FLOWAGE EASEMENTS ON THE MANAGEMENT UNIT.

(b) Rationale. Flowage easements were purchased on the management unit after the testing of the Russell Creek Outlet Canal flooded the area.

(6) Development and Management Concepts. Refer to plate 5-20 for the conceptual development plan for the Russell Creek Flowage Management Unit.

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Mill Creek Master Plan Coordinator