Lower Dolores River Draft Implementation Plan Released - Colorado
Cortez, Colorado - After several years of work to restore healthy flows in the Lower Dolores River, American Whitewater and a small group of water and conservation interests in the basin have released a new Implementation, Monitoring, and Evaluation Plan for new management opportunities below McPhee Dam and Reservoir. The Plan's goal is to restore native fish populations between the dam and the San Miguel River, while protecting world-class whitewater boating opportunities, and other Wild and Scenic values.
HISTORY AND BACKGROUND
The Dolores River has had significant modifications to its flow regime over the last 120 years that have resulted in changes to native fish habitat. The first significant modification was the trans-basin diversion of water through the Main Canal No. 1 in 1885. The Main Canal No. 1 diverted most of the flow of the river during irrigation season leaving only tributary inflow and leakage through the diversion structure in the river below. The second significant modification was the construction of McPhee Dam in 1984 (aka the Dolores Project). McPhee Reservoir now stores most of the flow of the river throughout the entire year with spills only occurring during spring on years when the reservoir can't store all the inflows. The Dolores Project also includes a storage allocation for a fishery pool that provides for perennial baseflow below the dam. McPhee Reservoir has allowed an increase in irrigated acreage, satisfied long-standing water rights obligations to the Ute Mountain Ute Tribe, and firmed water supplies for existing farms and municipalities, resulting in significant changes in the culture and the economy of the surrounding communities. However, both the Canal and McPhee Dam have resulted in changes in downstream river processes that once maintained the habitat that native fish had adapted to and depended on for millions of years.
Despite the transbasin diversion through Main Canal No. 1, recreational boating emerged in the 1960s and 1970s as another use of the river's water. Both private and commercial rafters enjoyed the annual runoff for what is commonly described as one of the most pristine and continuous wilderness river experiences in the west. Incredible scenery, solitude, and the occasional whitewater thrill drew boaters from across the country to experience what many called the other Grand Canyon. With the construction of McPhee Dam, the boating experience also changed. The dam brought changes to the timing and size of boating releases, as well as the occasional years without managed spills (e.g., 2001-2004).
Around the same time as recreational boating began on the Dolores River, there was a growing recognition of the value of natural environments as an important element of community character and of the significant economic value that can be generated when these natural values are conserved. Official recognition of the recreational, scenic and wilderness qualities of the Dolores River corridor first came in 1976 during a federal planning review, which found the river downstream to Bedrock as warranting inclusion into the National Wild and Scenic Rivers System under the 1964 Wild and Scenic Rivers Act. Although the construction of the dam significantly affected aquatic species’ composition and movement, most of the wild and scenic values that were assessed in the 1970s remained unchanged.
RECENT ACTIONS AND CURRENT STATUS
Similar to other 'working rivers' throughout the Colorado River Basin, Colorado Parks and Wildlife (CPW) fishery data show that populations of the roundtail chub (Gila robusta), flannelmouth sucker (Catostomus discobolus), and bluehead sucker (C. latipinnis) in the Dolores River between McPhee Dam and the San Miguel River confluence have been trending downward since the early 1990s. Some reaches that were previously occupied by native fish soon after the Dolores Project was completed have been abandoned. The threat of a federal listing of these native, warmwater fish under the Endangered Species Act necessitates the continuance of efforts to reverse current population trends. Should any of the three native fish in the Dolores River be listed, the implementation of the conservation actions described in the Lower Dolores River Implementation, Monitoring, and Evaluation Plan ('Implementation Plan') would reduce the risk that federal restrictions could adversely affect Dolores Project water deliveries. The Implementation Plan describes the efforts that are being undertaken to improve populations of these fish while preserving and possibly enhancing the many values that the river provides to the surrounding communities.
The Dolores River Dialogue
In 2004, the San Juan Citizens Alliance approached the Dolores Water Conservancy District and the two organizations jointly established the Dolores River Dialogue (DRD), a public stakeholder-driven process intended to address the ecological conditions below McPhee Dam (http://ocs.fortlewis.edu/drd/).
DRD Purpose Statement
"The DRD is a coalition of diverse interests, whose purpose is to explore management opportunities, build support for and take action to improve the ecological conditions downstream of McPhee Reservoir while honoring water rights, protecting agricultural and municipal water supplies, and the continued enjoyment of rafting and fishing."
The DRD created a cooperative environment that enabled the water and land managers operating in the region to discuss and evaluate opportunities to protect the natural, recreational and cultural values of the river while honoring existing private property and water rights.
Lower Dolores Working Group
In December 2007, the San Juan Public Lands Center (USFS and BLM) released their Draft Land Management Plan that found the Dolores River from the outlet of McPhee Reservoir to Bedrock to be "preliminarily suitable" for inclusion in the National Wild and Scenic Rivers System. This determination reflected a similar finding to the 1976 federal planning review, and re-ignited local concerns over federal intervention under the Wild and Scenic Rivers Act. At the invitation of the San Juan Public Lands Center, the DRD initiated the Lower Dolores Working Group (LDWG) in December of 2008, which brought an even larger and broader group of stakeholders than those of the DRD together to discuss how the river corridor could be managed to balance community needs with the requirements of the federal land planning process. The focus of the LDWG became the crafting of a management strategy that would serve as an alternative to the lower Dolores River’s inclusion in the Wild and Scenic Rivers System, protect previously identified outstandingly remarkable river values, and permanently remove a 'suitability' determination for this reach of the Dolores River.
After 18 months of intensive deliberation, the LDWG decided to begin the process of establishing a National Conservation Area (NCA) that encompassed most of the Dolores River corridor from below McPhee Dam to roughly the town of Bedrock, Colorado. A legislative subcommittee made up of members of the LDWG created an outline for the NCA legislation that included conceptual agreements about minerals and mining, grazing, travel, property rights and outstandingly remarkable value protections, but could not come to agreement on how to address water management to improve conditions for native fish without undermining current obligations to ranchers and farmers. In an effort known as A Way Forward, three independent native fish experts were commissioned to review existing scientific and hydrologic information and identify opportunities to improve the status of the 3 native fish species previously mentioned. The A Way Forward report provided the foundation for an Implementation Team (IT) to formulate the Implementation Plan that would put the recommendations of the scientists into a strategic framework for consideration by the entities with authority and responsibility to act on the opportunities identified in A Way Forward.
Goal Statement of the Implementation, Monitoring, and Evaluation Plan
"The goal of the Implementation Team is to protect and enhance the long-term viability of native fish populations in the Dolores River below McPhee Dam. This Implementation, Monitoring and Evaluation Plan details the specific actions that Implementation Team partners will take to ensure the enduring protection of roundtail chub, flannelmouth sucker, and bluehead sucker in the Dolores River. This plan provides the framework for a coordinated, long-term resource management strategy that will protect native fish and that can provide a partial basis for an alternative to a 'suitability' determination under the Wild and Scenic Rivers Act. The Implementation Team partnership is based on the premise of shared responsibility, and will proceed with respect for existing water rights and water allocations and the prior commitments imbedded in Dolores Project authorizations." (6/2012)
The Implementation Team emerged from the A Way Forward and Lower Dolores Working Group legislative processes, and is charged specifically with assessing, implementing, and evaluating the opportunities described by the scientists, and to adapt their management based on the monitoring and evaluation of specific actions. The Implementation Plan describes the approach taken to implement each opportunity, what may be necessary to overcome implementation issues, and defines specific quantifiable fishery metrics that can be monitored to assess the status and sustainability of native fish populations. The partners who comprise this team were selected because of their critical roles relating to implementation of the opportunities, the commitments made in prior Dolores Project authorizations, or their representation of broad constituencies that may be critical toward achieving the objectives for native fish.
The Implementation Team has representatives from each of the following organizations:
- U.S. Bureau of Reclamation (BOR)
- U.S. Forest Service and Bureau of Land Management (USFS/BLM)
- Dolores Water Conservancy District (DWCD)
- Montezuma Valley Irrigation Company (MVIC)
- Colorado Parks and Wildlife (CPW)
- Trout Unlimited (TU)
- American Whitewater (AW)
- San Juan Citizens Alliance (SJCA)
- The Nature Conservancy (TNC)
The Implementation Team entities represent a broad set of interests and define a spectrum of constituencies that these organizations are beholden to. Each has its own internal structure, processes, and definitions of success. However, it is recognized that all Implementation Team participants have something to gain from success of the Implementation Plan, and something to lose from failure.
Overview of Opportunities Identified By A Way Forward
The A Way Forward fishery scientists itemized nine management opportunities they felt should be pursued or at the least, thoroughly discussed to assess the feasibility of implementation. The Implementation Plan addresses these opportunities as they were presented in the AWF scientists' final report. The entire list of opportunities presented by the scientists is included below:
- Spill Management
- Baseflow Management
- Geomorphic Processes - Sediment Flushing Flows
- Geomorphic Processes - Habitat Maintenance Flows
- Thermal Regime Modification
- Reduce Warm Water Invasive Effects - Disadvantage Smallmouth Bass Reproductive Success
- Reduce Cold Water Invasive Effects - Discontinue Stocking
- Reduce Cold Water Invasive Effects - Reduce Brown Trout Reproductive Success
- Supplement Adult Native Fish
These recommendations represent a spectrum of ideas that address the many factors that the scientists felt were negatively affecting native fish populations and include not only flow-specific recommendations (e.g., changes in spill management or baseflow enhancement) but also non-flow management strategies such as stocking native fish or actively managing against warmwater or coldwater invasive, predatory fish (e.g., smallmouth bass and brown trout). The scientists noted repeatedly that the impacts to the native fishery were multi-faceted, and no one action was deemed the silver bullet that could reverse current population trends. Rather, they emphasized that all feasible actions should be implemented as soon as possible because of the precarious status of the native fish in the Dolores River below McPhee Dam.
Assessing and Ensuring Native Fish Viability
The Implementation Team tiered its approach to assessing native fish viability off the 'Rangewide Conservation Agreement and Strategy for Roundtail Chub (Gila robusta) , Bluehead Sucker (Catostomus discobolus), and Flannelmouth Sucker (Catostomus latipinnis)’ (2006; Appendix D in the Implementation Plan) that many of the institutions on the Implementation Team are signatory to. The Conservation Agreement was developed to provide a framework for the long-term conservation of the three species throughout their ranges through a collaborative and cooperative effort amongst resource agencies in Wyoming, Utah, Colorado, New Mexico, and Arizona. Native fish goals developed by the Implementation Team are in line with the Conservation Agreement, and in addition, emphasize protection and enhancement measures rather than maintenance given the current status of the fisheries. Enhancing the fishery in the lower Dolores River will involve achieving numeric targets by reach that are based on existing sampling data and the region-wide literature about these three species; it does not involve trying to achieve native fish populations analogous to pre-water development times. Monitoring is intended to detect changes in the abundance, distribution, and population structure of the three species and evaluation will occur as a feedback loop for adjusting management efforts.
DESCRIPTION OF OPPORTUNITIES
Spill management was identified by all A Way Forward scientists as a core opportunity that could provide multiple benefits to the downstream native fishery (specifically, geomorphic functions of flushing and habitat maintenance flows; maintenance of a native thermal regime; and conservation of the base pool). As spill volumes increase, the opportunity to affect multiple factors that may benefit the native fishery and improve whitewater boating opportunities also increase. The challenge is to find ways to ensure fishery benefits for spills of all sizes while minimizing the risk of not filling McPhee Reservoir and any adverse impacts to whitewater boating.
To meet this challenge, the Implementation Team outlined spill volumes of different magnitudes (25K AF, 50K AF, 100K AF, and 200K AF) and asked that hydrographs for each spill magnitude be developed by IT members representing the fishery, boating, and operations constituencies, which resulted in three separate hydrographs for each spill scenario (Figure 1 example for 50K AF). The objectives, release volumes and timelines for decision-making for each hypothetical scenario are outlined such that decision makers can use the BOR's official runoff forecasts to create the best opportunity for native fish spawning success while minimizing risks to other water users of the Dolores River.
Figure 1. Example of composite hydrograph (shaded) and 'resource specific' hydrographs used in the development of spill guidelines for a managed spill forecast of 50,000 AF.
Improvements in base pool size and management have been cited in prior studies of the fishery downstream of McPhee Dam as necessary steps toward maintaining viable native fish populations, and the A Way Forward scientific panel affirmed this basic need by highlighting it as a primary opportunity to achieve benefits to the native fishery. Habitat quality and quantity is a limiting factor for native fish survival in the reach of the Dolores River between the dam and the confluence of the San Miguel River, and the current base pool size limits the flexibility of fishery pool managers (the Dolores Project Biology Committee) to do much other than provide minimal flows for existing fish to survive. Though many factors contribute to the downward trends of native fish in the Dolores River, the lack of adequate baseflow diminishes the carrying capacity within the reach, and limits the resiliency of native fish to respond to other stressors like drought, predation, competition, sedimentation, and reduced peak flows. Improving the size and management of the base pool is a critical component of improving native fish viability below McPhee Dam.
While baseflow enhancement was clearly identified by the scientists as one of the primary opportunities that need to be pursued in conjunction with other opportunities such as spill management, thermal regime modification, and predator management strategies, it also is far more complex. The goal of increasing the baseflow management pool to 36,500 AF per year by adding water to current baseflow pool supplies is well documented. But the strategies, tradeoffs, and actual costs related to securing this additional water are, as yet, not fully analyzed and understood. Therefore, implementation strategies for meeting this goal have yet to be defined by the Implementation Team and are not included in this inaugural iteration of the Implementation Plan.
Geomorphic Processes - Sediment Flushing Flows and Habitat Maintenance Flows
The AWF scientists independently validated earlier conclusions that the reduction in overall stream power following dam construction has impacted native fish habitat in the river. The scientists also agreed that spill management designed to achieve multiple purposes would be the most beneficial use of projected surplus water, but their report suggests that managing spills to meet specific flushing or habitat maintenance targets may be subordinate to meeting other native fish opportunities (e.g., thermal regime modification).
Monitoring the effects of spill management against flushing and habitat maintenance objectives will allow refinement of flow targets that achieve multiple purposes or when specific sediment management goals become a priority. As monitoring of instream habitats and floodplains continues, the Implementation Team may consider more detailed studies of how sediment flux affects these habitats, including sediment transport modeling and calibration using field monitoring techniques.
Thermal Regime Modification
A Way Forward scientists all pointed out the benefits of trying to create a thermal regime below McPhee Dam that more closely reflected a natural pattern of water temperature warming during the spring. The two most dominant variables controlling water temperatures below the dam during this period are air temperature and discharge volume.
Based upon their analysis of thermograph-hydrograph overlays, they emphasized the need to manage the thermal regime to provide the correct thermal cues at times appropriate for natural life stage functions (e.g. spawning, growth). They also stated that a thermal regime with a more natural pattern could also return a more natural diversity and productivity to the invertebrate community.
Successfully managing the thermal regime on low flow years comes with the risk of fewer irrigation days and fewer boatable days. To better understand the risks, the Implementation Team did cursory 'risk analysis' of the 'early release of projected spill' proposal. Clearly on large spill years (e.g., 2005, 2008) it is relatively risk-free, as BOR operations criteria mandate that some water be released through April and early May to ensure capacity in the reservoir when peak flows occur. During years with small spill forecasts and uncertainty as to whether that runoff will be realized, it was important to quantify the amount of 'temperature suppression' water that might be necessary prior to the reservoir filling, and relate that volume to the overall magnitude of the projected surplus or translate it to 'lost boating days', as typical operations under 'fill then spill' would have targeted managed releases to meet one of the boatable flow criteria (usually 800 cfs minimum). These discussions and analyses allowed for the development of the two 'low volume' spill hydrographs presented in the Implementation Plan (25KAF, 50KAF) (see Figure 1 in Spill Management section above for 50 KAF example), and in general, the boaters agreed that additional certainty of timing and volumes of releases would mitigate any lost boating days that might otherwise occur.
Reduce Warm Water Invasive Effects
Non-native fishes have been a part of the Dolores River ichthyofauna for over 100 years. High spring runoff and turbidity, extremely low baseflows, and poor water quality associated with mining influenced the entire fish assemblage. These early conditions may explain in part why white sucker, and other invasive fish species, never established themselves in the Dolores River in appreciable numbers. However, after McPhee Dam was constructed, the creation of a warmwater, sport fishery in the reservoir increased the opportunity for non-native fish to migrate to the lower Dolores River. Numerous fishes including kokanee salmon, trout, smallmouth bass, green sunfish and yellow perch have all emigrated from the reservoir.
The AWF scientists and the Implementation Team recognize that the management actions and recommendations by CPW and the Dolores Project Biology Committee are currently limiting the escapement of non-native warmwater fishes from McPhee Reservoir and the effects of these fish downstream.
Reduce Cold Water Invasive Effects - Stocking and Regulatory Actions
The Dolores Project mitigation for loss of the coldwater fishery inundated by the reservoir was the creation of a “quality trout fishery” below McPhee Dam, likely modeled on other high-quality tailwater fisheries in Western rivers (e.g., Gunnison Gorge, Fryingpan, Navajo, Flaming Gorge, etc.). To avoid escapement of unwanted non-native fish into the Dolores River from McPhee Reservoir, water is released out of the lowest of the outlets. Due to the coldwater release, coldwater habitat will persist below the dam, while the non-native warmwater species remain in the reservoir. The creation of a coldwater fishery below McPhee Dam also is an effective secondary means of curtailing effects of non-native fish accidentally released through the outlet works, creating a coldwater barrier between the dam release point and the occupied habitat that begins about 30 miles below the dam.
Management of fisheries in Colorado is the responsibility of Colorado Parks and Wildlife, and CPW routinely uses stocking and various management tools to produce a desirable outcome for the fishing public, and to meet conservation goals outlined in its Strategic Plan and in inter-agency agreements (e.g., 'Three Species Conservation Agreement', Appendix D in the Implementation Plan). The AWF Panel introduced the idea that CPW could change stocking or management actions to alleviate trout predation on native species, so the Implementation Plan touched on current practices, potential changes, and potential consequences of changing stocking or management policies below McPhee Reservoir.
Supplement Adult Native Fish
Supplementing warmwater native fishes by stocking was an opportunity called out by the A Way Forward science report as one potential management tool that could be used to improve the status of native fishes in the Dolores River. Developing warmwater captive fish broodstocks is a relatively new conservation strategy in the State of Colorado. CPW has developed and maintained a captive roundtail chub broodstock from the San Juan River Basin since 2002 but has no similar program for bluehead or flannelmouth sucker.
Stocking of conservation fish species is different from 'put and take' or 'put and grow' strategies traditionally used for fish stocking, where sustainability of the fishery is the objective rather than providing for a recreational angling experience. Suitable habitat for warmwater native fish species must be present before stocking fish; otherwise the goal of a sustainable fishery will not be met. For example, the San Juan River Basin Endangered Recovery Program addressed the timing, magnitude, and duration of flows from Navajo Dam before embarking on an aggressive stocking program for Colorado pikeminnow and razorback sucker. A non-native predator suppression strategy was also implemented at the same time as stocking.
The operation of McPhee Dam to mimic a more natural spring hydrograph, implementation of non-native fish suppression efforts, monitoring geomorphic processes to provide sediment flushing and habitat maintenance, and improving the baseflow pool will set the stage for improved conditions for native, warmwater fish in the lower Dolores River. Currently, Implementation Team members, and the organizations they represent, continue to seek broadly accepted solutions “to protect and enhance the long-term viability of native fish populations in the Dolores River below McPhee Dam”.
For More Information
Go to the DRD Website http://ocs.fortlewis.edu/drd/ and click on Implementation Team for:
- The complete Implementation, Monitoring and Evaluation Plan and Appendices
- A graphic overview entitled, “Improving the Health of Native Fish and Protecting Water Supplies: An Action Plan”
- This narrative Executive Summary of the Implementation Plan
- The “A Way Forward” scientists report and oversight panel notes
- All Implementation Team Meeting Summaries
 'Stream power' is a function of flow; specifically stream power is directly proportional to the square of the velocity of moving water (i.e., Power ~ V2) and is a measure of how much work flowing water does to move sediment and re-configure instream and near-stream environments. In general, flow velocities increase as stream discharge increases.