Current State of Fish and Fish Habitat in Mill Creek
by Ty Dann

To many individuals, particularly anglers, fishing in the Walla Walla area is a very important issue, especially in Mill Creek.  The current state of fish habitat is dismal.  Dewatering, lack of adequate habitat, and fragmentation of healthy populations are some of the factors contributing to the poor state of Mill Creek.  Examining the habitat of the area greatly helps one understand the current state of fish and offers suggestions for the future.  Similarly, understanding the demands on the area (i.e. irrigation, city needs, angler’s rights, etc.) and the various angler organizations and fish management agencies involved provides a view of the political arena as it relates to fishing and fish habitat.  With the establishment of the Bull Trout as a threatened species under the Endangered Species Act (ESA), the conflict over fish habitat management becomes even more critical.  The establishment of a non-profit organization to represent the interests of anglers, fish and habitat in the area could alleviate many concerns in the area by increasing angler and fish influence in the political arena.

Bull Trout

Walla Walla River Basin

The Walla Walla River Basin (WWRB) is situated in southeast Washington and northeast Oregon.  The river basin encompasses five counties: Umatilla, Union and Wallowa in Oregon, and Walla Walla and Columbia in Washington.

Humans in the Basin
Historically, the lands belonged to the Walla Walla, Cayuse and Umatilla Indian Tribes.  As a result of the Treaty of 1855 with the federal government, the Tribes have reserved rights on the land, including the harvesting of salmon in the WWRB.  Roughly 70 percent of the population within the WWRB lives in the greater Walla Walla area.

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Land Use
The dominant land use in the WWRB is agriculture, comprising 58 percent of the land use, and is the driving force behind the economy.  The next largest classification of land is forestland, which makes up a quarter of the WWRB.  Ninety percent of the land is privately held, nine percent federally owned and the remainder state land.  Sixty-nine percent of water usage in the basin is devoted to irrigation, 22 percent to municipal uses, and the remaining nine percent to industry.  The Corps currently has six projects in the WWRB, two along Mill Creek (the channelization of Mill Creek through Walla Walla and the Bennington Lake Project).

Corps description of habitat degradation
“Aquatic habitat quality in the Walla Walla River and its tributaries has been dramatically impacted by land management practices that were gradually adopted as the region was settled by Europeans” (US Army Corps of Engineers, Walla Walla River Watershed Reconnaissance Report, 2-7, 2-8).

The Walla Walla River Watershed Reconnaissance Report denotes five factors which directly causes degradation to fish habitat:

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Mill Creek

Upper Mill Creek
Mill Creek flows from its upper reaches in the Blue Mountains in northeastern Oregon through Walla Walla and College Place to meet with the Walla Walla River west of Walla Walla.  Its headwaters area is the Walla Walla municipal water source.  A 1918 agreement with the United States Forest Service placed the watershed off limits to any development or human activity to maintain it as a clean, healthy natural environment.  The only human influence, other than the occasional elk hunt to maintain healthy riparian zones, is the city intake dam, screen and pipeline.  Up to twenty-eight cubic feet per second drawn down from this area for the city water supply are supplemented by deep aquifer pumping during the summer months.  Fish screens are being built to new NMFS standards at the screening site in 2001.  At the time (1989) the intake structure and ladders were built to specifications.  This provides an example of the changing knowledge and ecological awareness with regard to the needs of the local fish populations (Robert Gordon, Water System Manager, City of Walla Walla, personal communication, October 29, 1999).

Mill Creek Project
The creek flows down through the Blues to Rooks Park where the Mill Creek Project serves as a major impediment to natural stream flow.  Major floods in the late 19th and early 20th centuries led to the Mill Creek Flood Control Project, established under the Flood Control Act of 1938.  The project was completed by 1942 and consists of a diversion dam at Rooks Park and an off-stem reservoir named Bennington Lake.  Four intake gates divert water to the lake, which serves as a recreational area and flood storage facility.  The lake is stocked with rainbow trout by the Department of Game and Fish and serves as the local fishing hole (Phil Binge, Outdoor Recreation Planner, Department of Recreation, US Army Corps of Engineers, personal communication, October 25, 1999).

Channelized Section of Mill Creek Project
Below the diversion dam at Rooks Park is the channelized section of Mill Creek, which runs though Walla Walla.  It consists of a concrete channel with various structures that basically serves as concrete chute through the city.  It was constructed as part of the Mill Creek Project to help control flooding in the area and in doing so has created an artificial environment.  This section of Mill Creek seasonally dewaters, typically in the summer months when the irrigation demand is high and stream discharge is low, eliminating the area as a possible place for fish to live.

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Yellowhawk/Garrison/Russell Creeks
While the diversion to various creeks along Mill Creek contributes to the dewatering problem, it does help fish populations in the area.  By diverting water to unimpeded waterways, migrating fish are allowed access to Mill Creek above the normally dry, channelized section that flows through town.  Phil Binge described the presence of steelhead near the Mill Creek Project; they now come up Yellowhawk and Garrison Creeks because the state of Mill Creek is so poor.

How fish are affected

Upper Mill Creek
The careful management of upper Mill Creek is intended to maintain high water quality for Walla Walla residents, and also serves to create healthy habitat for Bull Trout and other fish in the area.  It is one of the few spawning grounds for Bull Trout, listed as a threatened species, in the WWRB.  Other than the very upper reaches of the Touchet River and the North and South Forks of the Walla Walla, Mill Creek is the only spawning ground in the Walla Walla Watershed; it also serves as a steelhead spawning and rearing ground.  The health of upper Mill Creek is largely due to the absence of negative human influences, such as timber harvesting, agriculture, etc., that degrade habitat quality further downstream.

Mill Creek Project
An inherent challenge exists in Mill Creek.  The Project was designed in the 1930s and 1940s as a means for flood control when planners weren’t as ecologically wise.  We now face the issue of how to incorporate new conservation values into old systems.

Since fish are killed in the intake gates, some actions currently being considered include: a pump/screen system at the forebay, additionally, a screen placed near the fish ladder should make it more attractive to fish and discourage fish from entering the sluiceway. Although the forebay area does provide habitat for many species, the barriers imposed by the Mill Creek Project generally have a negative influence on fish in the area.  The Project has significantly altered the course and flow of the creek from a braided stream to a diversion dam to an off-stem lake followed by a channelized chute through town.

The Corps of Engineers has noted many problems in Mill Creek, most notably the failure of the stream channel to provide adequate continuous habitat for fish.  The structures in the channel, as well as irrigation withdrawals, create passage limitations for fish.  The channel increases water temperatures, especially harmful to Bull Trout and salmonids, removes habitat, increases water velocity, and impairs water quality and pH, due to flow through town and runoff from agricultural sites.  The EPA website rates Mill Creek as “impaired water” due to temperature, instream flow and pH (Case ID #WA_SS77BG17.113_1998).  Though problems for fish are readily identified within the Mill Creek Project, these concerns must be counter balanced by the importance of flood protection for Walla Walla.  Additionally, some fish species are able to migrate up Mill Creek via Yellowhawk and Russell Creeks.

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Mill Creek is seasonally dewatered after reaching the Mill Creek Project and Walla Walla area. This is largely due to the numerous diversions drawing water from Mill Creek (i.e. agricultural enterprise, Yellowhawk Creek, etc.). The establishment of minimum stream flows should greatly help to alleviate this problem and could be seen as a way to incorporate the “water rights” of fish into the existing water right system. Coupled with the importance of flood protection provided for Walla Walla, having fish run up various creeks lessens the priority of the dewatering problem in Mill Creek.

low flow in Mill Creek

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Fishing in the community

Organizations involved
-The United States Army Corps of Engineers:
The Corps currently operates two projects directly in Mill Creek, the Mill Creek Project and the channelization of the creek through Walla Walla, that greatly affect fish habitat and fishing in the area.  The Corps is also highly involved in the future of the fish in the area as it oversees the larger dams on the Columbia/Snake Rivers that threaten the future of migratory salmon and trout.  While salmon may be absent from the Walla Walla Rivershed, migrating Bull Trout and steelhead are greatly impacted by the dam structures in the Columbia/Snake River system.  If habitat and migration were improved, local fish populations in Mill Creek should benefit greatly.

-Washington Department of Fish and Wildlife:
The Department of Fish and Wildlife states its mission is to “provide sound stewardship of fish and wildlife.”  They are responsible for establishing and enforcing the rules regulating fishing and hunting in the state of Washington.  In the establishment of the regulations, a Comment Period on new rules is offered.  Interested groups, such as the Tri-State Steelheaders, and individuals provide feedback, thus influencing public policy making (John Geidl).

-Tri-State Steelheaders:
Established in 1965, the Tri-State Steelheaders is a recreational fishing organization dedicated to the protection of fish in the area.  Active member John Geidl explained the aims of the Tri-State State Steelheaders as a three-pronged approach: conservation, education and outreach.  Through projects such as the Nine Mile Creek Planting Project and various other stream restoration projects, the Tri-State Steelheaders work to preserve fish habitat in the area.  Through their “Salmon in the Classroom” Program, they educate children about salmon and trout.  They also operate an Outreach program that introduces fishing as a positive influence into the lives of children.

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Bull Trout and Steelhead
Bull Trout are described in the Walla Walla River Watershed Reconnaissance Report as a “wide ranging, typically non-anadromous species that inhabits most of the cold lakes, rivers, and streams throughout the western states and British Columbia…Bull Trout require complex forms of in-stream cover…One of the problems facing Bull Trout is the number of passage impediments in WWRB, and especially Mill Creek. Bull Trout migrate many kilometers within a given basin during the winter when H2O temperatures drop to the point that allows them unrestricted access throughout the WWRB. Their population is fragmented because passage impediments and barriers prevent them from reaching many areas of the Walla Walla River Basin.”  (US Army Corps of Engineers, Walla Walla River Watershed Reconnaissance Report, 2-14)

According to author Craig Knowles of the Bull Trout Foundation, this scattering of populations and lack of adequate habitat makes Bull Trout susceptible to what they term “the standard formula for extinction:
1.  Fragment the population;
2.  Degrade the habitat; and
3.  Introduce catastrophic events.

They also note irrigation as creating four major problems for Bull Trout: "It reduces in stream flows.  The water that it returns to streams tends to be significantly warmer than the water it takes out.  It adds sediment to streams; and its unscreened diversions frequently kill migrating juvenile Bull Trout.”

Furthermore, the establishment of dams and irrigation systems has decimated migratory Bull Trout populations.  The fragmented populations that exist are isolated and vulnerable to habitat degradation without the link to other sections of the species’ gene pool.  Knowles states: "The problem is that dams and other activities have wiped out most of the migratory Bull Trout populations, leaving mainly resident fish.  This means that the 438 remaining populations are often isolated from one another.  Many of these scattered groups have just 200 to 1,000 individuals each.  Genetically, these numbers are too small to assure survival; conservation biologists estimate that at least 2,000 individuals are needed to maintain genetic health and diversity."

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While the listing of Bull Trout as a threatened species will protect the species in the short run, long term survival necessitates changes in the entire watershed.  In Mill Creek’s case, the entire Columbia-Snake River System must be examined to restore migratory populations to ensure the future for Bull Trout in the Northwest.

Bull Trout in Mill Creek are affected by many different management systems.  Due to the Walla Walla city water pipeline, local government directly affects their habitat in the area.  The Corps is involved as it manages the dams and numerous projects regarding irrigation and flood protection (i.e. Mill Creek Project, etc.).  Other state and federal agencies, such as the Department of Fish and Wildlife and the EPA, all affect the livelihood of the trout in one way or another.  With the listing of Bull Trout under the ESA, it comes under the overarching influence of federal rules and regulations, which complicates the relationship between those involved with Bull Trout.

Endangered Species Act
The Endangered Species Act of 1973 has become one of the key pieces of environmental legislation today.  With the listing of Bull Trout as a threatened species on June 10, 1998, the heavy handed influence of the ESA came upon Mill Creek and the Walla Walla area.  Chris Pinney, fisheries biologist for the US Corps of Engineers, describes the ESA as very powerful, with the potential to change management from an incremental process to very command and control type of government.  He indicates the change from before and after as very noticeable.  There really wasn’t any impact on the status quo until the ESA kicks in.  Phil Binge states the ESA listing hasn’t really affected the area, at least Lake Bennington. Fishing in the lake has not been restricted due to the listing of the trout.  Tri-State Steelheader John Geidl stated that the listing has had more of an impact on local fishing in Mill Creek than anything else.  Anglers are allowed to use only artificial and barbless hooks when fishing.  This restriction is an attempt to avoid the catching of Bull Trout or smolts of steelhead or Bull Trout.  He stated that most anglers will support the no takings policy and that their organization wishes to cooperate and work with the Washington Department of Fish and Wildlife.  In return, he said, Fish and Wildlife recognizes the limits this puts on anglers and works to upgrade other areas (i.e., Tucannon River, Quarry Pond) to compensate for the
reduction of fishing in the area.

In their final ruling for the Bull Trout, the Fish and Wildlife Service determined threatened status for the Columbia River population due to declining numbers and habitat.  The ruling states that the remaining subpopulations have been isolated into fragmented habitats that support low numbers of fish and are inaccessible to migratory Bull Trout.  It cites, as the primary causes of decline to be habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, past fisheries management practices and the introduction of non-native species.  The ruling allows the taking of Bull Trout if in accordance with applicable state and Native American Tribal fish and wildlife conservation laws and regulations, and conservation plans approved by the Fish and Wildlife Service.


The current situation for fish in the Mill Creek area is troubled.  While there are sections, such as the watershed maintained for the city water supply, that provide adequate habitat for fish, a critical lack of healthy habitat describes much of Mill Creek.  Furthermore, the decimation of migratory fish through dams and irrigation systems in the area isolates the resident healthy populations into pockets lacking genetic diversity.  This heightens the risk for threatened populations, such as the Bull Trout, as healthy local populations may not have the genetic diversity to continue in the long-term.

With this in mind, effective management is necessary and needs to take into account the multitude of factors and their relationships.  The needs of the City of Walla Walla are a voice very much heard in the political arena, as are the needs of agriculture, flood control advocates, etc., but for the most part these needs overpower the needs of fish.  In effect, their “voice” in the political arena has been drowned out by the many needs of humans who have redesigned Mill Creek to accommodate those needs.

While the Corps and other agencies do allow for a comment period on all proposed plans, and groups such as the Tri-State Steelheaders represent the interests of anglers and subsequently fish, the possibility of setting up a “Friends of the Mill Creek” organization offers new, interesting options.  A group such as this could represent the interests of fish and wildlife in the area to protect habitat and influence the policy making debate towards the conservation of fish.  Specifically, this group could monitor, work with agencies and inform the general public on issues relating to fishing in the Mill Creek area.  The possibility of forming a coalition with other such groups in the local area (i.e., Friends of the Walla Walla, etc.) would allow for a greater audience and larger sphere of influence.

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