6
An Alternative for Missouri River Recovery

The Missouri River was located in the United States at last report. It cuts corners, runs around at night, lunches on levees, and swallows islands and small villages for dessert. Its perpetual dissatisfaction with its bed is the greatest peculiarity of the Missouri. Time after time it has gotten out of its bed in the middle of the night with no apparent provocation, and has hunted a new bed, all littered with forests, cornfields, brick houses, railroad ties, and telegraph poles. Later it has suddenly taken a fancy to its old bed, which by this time has been filled with suburban architecture, and back it has gone with a whoop and a rush as if it had found something worthwhile. It makes farming as fascinating as gambling. You never know whether you are going to harvest corn or catfish.

George Fitch, 1907

Reversal of the Missouri River ecosystem trends described in this report will necessitate decisive and immediate management actions. The actions offered in this chapter can be viewed as a starting point for management agencies and other basin stakeholders. This chapter’s action plan should not be interpreted as a set of rigid recommendations that must be closely followed, but rather as an example of the types of actions that might be taken and that might help stakeholders think broadly about the prospects for improving Missouri River ecology. Without notable changes to current Missouri River dam and reservoir operations policies, further ecological degradation is certain. If it is decided that restoring some portion of the Missouri River ecosystem’s benefits is a valuable social goal—and recovery of some of those benefits may have significant economic and social values— this chapter provides a suite of possible actions that might be taken.

Although these actions are offered as suggestions, management actions of the variety and magnitude offered in this chapter are essential if ecological conditions are to improve. The degree to which the key physical processes—overbank floods and cut-and-fill alluviation—need to be restored in order to significantly improve river ecology is not exactly known. Scientific research provides sound knowledge of the ecosystem’s fundamental



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The Missouri River Ecosystem: Exploring the Prospects for Recovery 6 An Alternative for Missouri River Recovery The Missouri River was located in the United States at last report. It cuts corners, runs around at night, lunches on levees, and swallows islands and small villages for dessert. Its perpetual dissatisfaction with its bed is the greatest peculiarity of the Missouri. Time after time it has gotten out of its bed in the middle of the night with no apparent provocation, and has hunted a new bed, all littered with forests, cornfields, brick houses, railroad ties, and telegraph poles. Later it has suddenly taken a fancy to its old bed, which by this time has been filled with suburban architecture, and back it has gone with a whoop and a rush as if it had found something worthwhile. It makes farming as fascinating as gambling. You never know whether you are going to harvest corn or catfish. George Fitch, 1907 Reversal of the Missouri River ecosystem trends described in this report will necessitate decisive and immediate management actions. The actions offered in this chapter can be viewed as a starting point for management agencies and other basin stakeholders. This chapter’s action plan should not be interpreted as a set of rigid recommendations that must be closely followed, but rather as an example of the types of actions that might be taken and that might help stakeholders think broadly about the prospects for improving Missouri River ecology. Without notable changes to current Missouri River dam and reservoir operations policies, further ecological degradation is certain. If it is decided that restoring some portion of the Missouri River ecosystem’s benefits is a valuable social goal—and recovery of some of those benefits may have significant economic and social values— this chapter provides a suite of possible actions that might be taken. Although these actions are offered as suggestions, management actions of the variety and magnitude offered in this chapter are essential if ecological conditions are to improve. The degree to which the key physical processes—overbank floods and cut-and-fill alluviation—need to be restored in order to significantly improve river ecology is not exactly known. Scientific research provides sound knowledge of the ecosystem’s fundamental

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The Missouri River Ecosystem: Exploring the Prospects for Recovery physical and biological processes. But despite this scientific knowledge, details of the ecological responses to site-specific, habitat-based restoration efforts at the community level in the Missouri River ecosystem are not yet clear. The key uncertainties in the science of the Missouri River are in how the ecosystem will respond to efforts to improve river ecology A RECOVERY ACTION PLAN The Scientific Basis for Recovery Restoring some portion of the Missouri River’s pre-regulation physical processes is the key to ecological improvements. Movement toward river recovery will necessarily be incremental and should be framed within an adaptive management approach. Details of the timing and the extent of specific management actions should be established through collaboration among scientists, managers, and the public. Restoration efforts should be implemented within a basinwide framework that recognizes the relationship of tributaries to the mainstem, of upstream areas to downstream areas, and of the river system’s main channel and floodplain. The recommendation to cast management actions within a basinwide framework is not meant to imply that all actions should be conducted simultaneously across the basin. On the contrary, a more reasoned approach, consistent with an adaptive management paradigm, would be to first identify and implement management actions that appear to offer substantial ecological improvements with minimal disruptions to people and floodplain infrastructure (the “low hanging fruit”). Management actions that are taken should be conducted in a spatially-coordinated manner that considers mainstem-tributary, upstream-downstream, and main channel-floodplain relations through the entire river system. Ecosystem processes that drive the ecology of the Missouri River include mainstem and tributary floods (and low flows) and cut-and-fill alluviation associated with meandering. The area in which increased meandering is most likely to produce rapid ecological improvements is the channelized portion of the river from near Nebraska’s Ponca State Park downstream to St. Louis. Creation of unconstrained corridors that provide room for the river to meander in an erosion zone (annual wet edge to wet edge) also is crucial for program success. In those areas identified for adaptive management actions, steps should be taken to lower, remove, or set back hardpoints on the filling bank or revetments on the cutting bank to widen the annual erosion zone before changes in flows are prescribed. Broadening the dimensions of the erosion zone (also known as top-width) also increases floodwater storage capacity of the floodplain. This, in turn, reduces the risk of downstream flooding in high flows associated with dam

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The Missouri River Ecosystem: Exploring the Prospects for Recovery releases that mimic the spring flood pulse. A substantial spring flood pulse in some stretches of the river would help provide the channel–floodplain connectivity that is ecologically important in large river–floodplain systems like the Missouri. Pioneer cottonwood and willow stands, along with more numerous snags, would increase roughness of the riverbed and floodplain surface and help decrease streamflow velocity. The erosion zone that would develop as a result of this action is required by native species, both in the river and on the floodplain, for their continued existence. Simply constructing man-made habitat to satisfy the life-requirements of complex organisms, without changes in fundamental physical processes, is not likely to yield substantial ecological improvements. Restoring some degree of natural river-based processes, like flooding and cut-and-fill alluviation, is essential to promote improved ecological conditions. The time frames in which there are likely to be noticeable ecological improvements are not known but are likely to vary throughout the river–floodplain ecosystem. The uncertainty of ecological responses to management actions provide further rationale for conducting these actions within an adaptive management framework that promotes an iterative process that includes actions, monitoring, evaluation, and learning. Current Mitigation and Restoration Activities Since the mid-1970s, the Corps has cooperated with the U.S. Fish and Wildlife Service and state conservation agencies to develop and implement projects to “mitigate the loss of fish and wildlife resources resulting from the construction, operation and maintenance” of the Missouri River navigation project, Sioux City to near St. Louis (USACE, 1981). Under other authorities and over this same period, the Corps has also carried out environmental restoration and monitoring activities along the lower Missouri River. The Corps has also carried out various environmental mitigation activities on the Missouri River mainstem designed to improve habitat and reduce the impacts of the dams on endangered species. In 2002, the Corps plans to evaluate the impacts of increased spring flows from Fort Peck dam on pallid sturgeon recruitment, spawning, and egg maturation. The 1986 Water Resources Development Act (WRDA 86) authorized the Corps to develop habitat on 18,200 acres of existing state and federal land on the Missouri River floodplain and to acquire and develop an additional 29,900 acres of land. Under this authority, the Corps has to date purchased 23,549 acres of land and has developed habitat on 4,295 acres. It has also constructed habitat on 2,504 acres of existing lands. Action under WRDA 86 is scheduled to be completed in 2006 at an estimated cost of $80 million (USACE, 2001). In the 1999 Water Resources Development Act, Congress authorized

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The Missouri River Ecosystem: Exploring the Prospects for Recovery acquisition and development of an additional 118,650 acres of land over the next 35 years at an estimated cost of $750 million. To date, no funds have been appropriated under this authorization, and transmittal to the Congress of the plan proposed by the Corps is awaiting Office of Management and Budget action. Under the 1986 authorization, restoration, and mitigation work has been completed at eight sites and is under way at nine sites, and acquisition is under way at nine additional sites. Projects include enhancement of flow through side channels and development of backwater areas, installation of pumps, and construction of control structures to create habitat. A coordination team representing the Corps, the U.S. Fish and Wildlife Service, and the Missouri River basin states identifies potential projects and prepares plans for their development. The Corps and officials from the state in which the project is located jointly assume duties for monitoring the impacts of these projects. Using other authorities (Section 1135, WRDA 86), the Corps, in cooperation with state and local agencies, has attempted to restore habitat at several other locations along the river’s navigable section. Furthermore, in the conduct of its operations and maintenance, the Corps has made efforts to modify dikes and related water-control structures to increase their utility to aquatic species. Although the team has provided for inter-agency and interstate cooperation, the effort is not designed to consider an ecosystem-level approach to restoration. To help evaluate the impacts of adaptive management actions, restoration projects and programs should be complemented by ecosystem monitoring. Along the Missouri River, however, relatively little funding has been made available to track the results of the restoration and experimentation that is being conducted. There have been efforts to obtain federal funding to establish a formal Missouri River Monitoring and Assessment Program (MOREAP). As this report went to press, the MOREAP had not been formally authorized. One proposed mitigation activity worth noting is a substantial release of warm water from Fort Peck Dam in 2002. Recognizing the potential ability of higher and warmer flows to provide hydrologic cues for pallid sturgeon, the Corps has planned a $4.4 million test of flow modifications from Fort Peck Dam. An initial test will involve discharges of up to 15,000 cubic feet per second beginning in May, 2002 and is to last 30 days. In 2003, the Corps intends to evaluate a release of up to 23,000 cubic feet per second during the same spring period (by comparison, peak, sustained flows in the 1996 controlled flood at Glen Canyon Dam on the Colorado River were roughly 45,000 cubic feet per second; Webb et al., 1999). The initial test will examine the ability of the Fort Peck spillway to increase water temperatures and to pass the needed flows. The full test in 2003 is

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The Missouri River Ecosystem: Exploring the Prospects for Recovery planned to address the same issues as the 2002 test, but with higher flows (USACE, 2001). Along with the Fort Peck releases, several other projects contributing to Missouri River ecological improvements have been completed or are being implemented, including Boyer Chute (Nebraska), Hamburg Bend (Iowa), Louisville Bend (Iowa), Grand Pass Conservation Area (Missouri), and The Big Muddy Refuge (Missouri). These projects are encouraging steps toward improved ecological conditions. But to ensure success, such ecosystem restoration actions should be coordinated across the Missouri River basin. Consistent with the adaptive management paradigm, they should be conducted in a stepwise manner so that outcomes can be evaluated and used to help inform future actions. These actions should be assigned priorities and schedules, they should aim toward clear ecological restoration goals, and their outcomes should be evaluated as management experiments, the results of which should be used as feedback within an iterative, adaptive management process. Restoration actions taken to date along the Missouri River do not fully meet these criteria. A Coordinated, Reach-Specific Approach The following reach-specific plan represents only one of many sets of possibilities for designing a comprehensive approach to improve Missouri River ecology. Such an approach is needed because improvements can and should be made in all reaches to improve the ecological state of the entire Missouri River ecosystem. Management actions must be coordinated among reaches because action taken in one reach affects downstream flow and sediment conditions. Practical constraints to new management actions and the guiding philosophy of adaptive management suggest the utility of a stepwise approach. For example, removing impediments to channel-widening will need to precede flow management to effect lateral channel movement. Additionally, some management actions will need initial refinement at the reach level before being applied more widely. In particular, prescribing flows that induce desired rates of channel movement will require some experimentation, given the range of environmental and social uncertainties. Some reaches also may have a higher priority for recovery than others because ecosystem processes in those reaches may be more compromised. A comprehensive approach to ecological improvements on the Missouri River will require different approaches within different river segments (Figure 6.1 shows the Missouri River basin and the numbered river segments described below). Segment 1 is the unchannelized reach between the headwater streams and Fort Peck Lake. Although much of this portion is considered the last remaining natural section of the Missouri River, Canyon Ferry Dam con-

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The Missouri River Ecosystem: Exploring the Prospects for Recovery FIGURE 6.1 Missouri River basin and river reaches. SOURCE: USGS, undated. trols discharge along a large portion and is instrumental in reducing the flood threat in Great Falls, Montana, where there is considerable floodplain development. Some degree of alteration is possible in this reach, although a greatly altered discharge at Canyon Ferry would impact Great Falls. A better opportunity for restoring riverine processes may be along the Missouri River downstream from the Marias River confluence at Loma, Montana, and along the Marias River itself (Gardner, 1994). Tiber Dam lies about 80 miles upstream on the Marias River and is already managed to provide effective flows for the Marias (Gardner, 1998), but could also be used to enhance Missouri River flows (effective flows are peak flows necessary to re-establish cut-and-fill alluviation processes. Effective flows may or may not be equal to bankfull, but bankfull is usually assumed to control the form of alluvial channels; Gordon et al., 1992; Stanford et al., 1996). Lake Elwell was impounded to provide storage for irrigation and to help reduce flood damages. The Bureau of Reclamation operates the reservoir primarily for flood damage reduction, fisheries, and recreation (Montana Department of Fish, Wildlife, and Parks, 1998). There are no communities between Tiber Dam and the Missouri River at Loma, Montana. The level of ecological benefits restored could be substantial on both the Marias and Missouri rivers if Lake Elwell were used to restore riverine processes along both rivers upstream of Fort Peck. Restoration activities would enhance

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The Missouri River Ecosystem: Exploring the Prospects for Recovery regeneration of cottonwood on the floodplain of both the Marias and Missouri rivers and enhanced habitats for native fish, including paddlefish, sturgeon, sauger, and chubs (William Gardner, Montana Department of Fish, Wildlife, and Parks, personal communication, 2000). Paddlefish and sturgeon are highly valued for both recreational fishing and for food value. Moreover, paddlefish eggs make high-quality caviar with high economic value, especially since sturgeon that have provided caviar in other nations have declined in abundance in recent decades. As a recreational fish, sauger are as highly-valued as are walleye; sauger would likely become far more abundant in this stretch of the river if more natural flow and habitat conditions were restored. Overbank flows would re-create active meandering on both rivers. The opportunity to create active meanders in this segment is enhanced because the Missouri River downstream from the Marias River is designated as a national monument (and formerly as a federal Wild and Scenic River); thus, there is only minimal floodplain development. Removal of Tiber Dam represents an alternative. Although the losses of the benefits of Tiber Dam would have to be carefully evaluated and considered, removal of the dam would provide a substantial improvement in sediment transport and would provide exceptional benefits for native fish species upstream from the Tiber Dam site, as well as for the species of the lower Marias and the Missouri River (Zollweg and Leathe, 2000). Bovee and Scott (in press) examined six scenarios for delivering larger peak flows to this reach and found enough operational flexibility in the system to restore more natural flood pulses to improve cottonwood regeneration without greatly compromising other values. Segment 3 includes the Missouri River downstream from Fort Peck Dam to the confluence of the Missouri with the Yellowstone River. This portion of the Missouri River has been impacted by cold water released from deep in the reservoir, by the elimination of effective flows, and by channel incision associated with the release of sediment-free discharge from the reservoir. The Montana Fish, Wildlife, and Parks Commission and the Corps of Engineers recently initiated a project to mitigate the cold, deep releases from Fort Peck Dam. Surface water would pass through the spillway and mix with deep turbine releases to increase seasonal tailwater temperature. Rock bank stabilization has been applied selectively to reduce bank sloughing. Significant bank erosion has precipitated landowner complaints, and subsequent bank stabilization projects have been constructed in the first 70 miles from Fort Peck Dam downstream to Wolf Point, Montana. Another restoration opportunity is near Culbertson, Montana, about 45 miles upstream from the confluence of the Missouri and Yellowstone rivers (Mike Ruggles, Montana Department of Fish, Wildlife, and Parks,

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The Missouri River Ecosystem: Exploring the Prospects for Recovery personal communication, 2000). There are erosion-control projects on the river’s right bank; the left bank for much of this segment is on the Fort Peck Indian Reservation. A cooperative project between tribal groups and the Corps to promote overbank flooding and meandering would decrease the need for right-bank stabilization. It would also improve the prospects of increasing the amount of water spilled at Fort Peck for temperature mitigation and would create annual flows to maintain active meandering. Increased top-width beginning a short distance downstream from Fort Peck would help to remedy the sediment imbalance in the entire segment. Wider, shallower, and more turbid bends would also result in greater warming of the especially cool releases from Fort Peck. The Milk River is a small, turbid, river that enters the Missouri River immediately downstream from Fort Peck Dam and provides an additional opportunity for recovering riverine processes. Stored Milk River and Saint Mary’s River water is fully allocated for irrigation uses. However, tradeoff analyses could be conducted to assess the relative benefits of using the Milk River for irrigation versus using it to recover some portion of natural riverine processes. The Bureau of Reclamation could investigate the prospects of removing the diversions on the lower Milk River and could investigate altering Fresno Dam operations. Both actions would promote downstream transport of sediment stored in Fresno Reservoir. Fresno Dam could be used to contribute discharge for additional and possible overbank flows below Fort Peck Dam. In addition, the water would be warmer than the water coming out of Fort Peck Reservoir. The Montana Department of Fish, Wildlife, and Parks has developed management objectives for this reach, including maintenance of streambanks, channels, and seasonal flows from the Milk and Poplar rivers to enhance fish reproduction (Gilge and Brunsing, 1994). Warmer and more turbid flows would provide better habitat for pallid sturgeon and the native chubs that have declined in abundance in much of the lower Missouri. Paddlefish, sturgeon, sauger, and the buffalo species would likely increase in abundance in this reach with the types of restoration actions described above. These fishes would provide excellent recreational fishing opportunities, as well as improved availability of quality fish for human consumption. Segments 3 and 4 include the Yellowstone River downstream from the Intake Diversion (a low dam on the Yellowstone River about 71 miles upstream from the Yellowstone-Missouri river confluence) and the Missouri River from its confluence with the Yellowstone to Lake Sakakawea. The diversion does not present a barrier to fish movement during high flows, but Forsythe Diversion, 237 miles upstream on the Yellowstone, may hinder fish passage (Penkal, 1992). The Yellowstone River’s flow is uncontrolled, and both flood and base flows still occur (Backes and Gardner, 1994; Tews, 1993). Although some limited bank stabilization has

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The Missouri River Ecosystem: Exploring the Prospects for Recovery been attempted along the lower Yellowstone River, the river still meanders to some degree. The free-flowing condition of the Yellowstone is crucial to this ecosystem’s integrity (Fred Ryckman, North Dakota Game and Fish Department, personal communication, 2000). Moreover, flow enhancement at Fort Peck Dam and at the Milk River dams, in concert with natural flows from the Yellowstone River, would provide substantial ecosystem benefits from the Missouri River–Yellowstone River confluence to the upper end of Lake Sakakawea (Greg Power, North Dakota Game and Fish Department, personal communication, 2000). Top-width increases could be facilitated by removing existing erosion control devices and by adjusting Missouri River flows downstream from the confluence of the Missouri River with the Yellowstone River. The greatest environmental threats in this segment include water depletions and diversions from the Yellowstone (which have reduced Yellowstone River flows by about 24 percent), oil industry activities, bank stabilization, and shoreline development below the confluence (Power, 2000). These segments are currently strongholds for paddlefish, sturgeon species, and rare native chubs. Additional river meandering in this segment would regenerate early-successional plant communities, thereby enhancing both floodplain biodiversity and riverine fish abundance and recovery. Segment 6 is the unchannelized reach downstream from Garrison Dam to Oahe Reservoir. This segment has been impacted by deep, cold-water turbine releases from Garrison Dam, by channel incision associated with sediment transport imbalance, and by selective bank stabilization. Because of the relatively short distance between Garrison Dam and Lake Oahe, and because of extensive floodplain development near Bismarck, North Dakota, opportunities for restoration actions here are limited compared to longer, undammed reaches farther upstream. However, increased top-width associated with active meanders and increased turbidity could mitigate cold water temperatures. Active meander subreaches interspersed among unaltered subreaches could be planned from the tailwater of Garrison Dam to Washburn, North Dakota, and from several miles downstream from Washburn to about Mandan, North Dakota. Another subreach with the potential to create active meanders exists several miles downstream from Bismarck to the upper end of Lake Oahe. The Heart River enters the Missouri River near Mandan, North Dakota. Heart Butte Dam impounds a large reservoir that has flood-control capability. The prospects of a controlled release from Heart Butte to enhance flows in the lowest subreach of this segment could be considered. Warmer, more turbid flows, resulting from river meandering and increased spring season discharge, would improve reproduction for all native fishes in this reach and would directly provide another recreational fishing base to enhance the valuable fishery resources in the large mainstem reservoirs.

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The Missouri River Ecosystem: Exploring the Prospects for Recovery Segments 10 and 11 include an unchannelized reach downstream from Fort Randall Dam to Lewis and Clark Lake. The segments have been impacted by the lack of effective and base flows, by sediment imbalance, by the elimination of primary energy sources (floodplain plant material, particularly from trees and grasses), by cool-water releases from Lake Francis Case, and by selective bank stabilization. But the segments still exhibit a landscape much like the pre-regulation Missouri River. Sand bars, islands, backwaters, and sidechannels are well-watered under current river operations. However, the biota reflect a different condition. Indices of the abundance of native invertebrates and fish are much lower for these segments than for even the channelized sections of the river (Hesse, 1999). These reaches have localized housing developments, but the floodplain is primarily agricultural land. The greatest constraint to recovering active meandering might be overcome by a program of sloughing easements. The segments were designated the Missouri National Recreational River in 1991, and the National Park Service completed work on a general management plan in 1997. The ecology of this entire segment would benefit greatly by recovery of active meanders, and Fort Randall Dam is well situated to assist in the recovery by providing restorative flows. Sand bar development would be enhanced. Pioneer cottonwood and willow communities would develop within the erosion zone on newly formed point bars. Warmer and more turbid flows, and changes to the timing of flows, could enhance native fish production in this stretch, especially for paddlefish, sturgeon species, and sauger. Higher spring flows could help create more sand bars, which were historically used by migrating waterfowl in the fall. Today, waterfowl simply fly past much of this segment and adjoining segments of the Missouri River. But these stretches are important destinations for anglers, and increasing waterfowl populations would provide enhanced recreational and aesthetic opportunities for both anglers and hunters. This region is strongly rural and is experiencing a general population decline. Many residents are moving to larger urban areas farther downstream. Schools are unifying and consolidating, and many small businesses are closing. Greater abundance of fish and wildlife could provide an economic resource to help offset the regional decline in the number of small family farms. For example, these segments of the Missouri River are currently included in the national bass fishing tournament schedule. Additional backwater habitat would likely increase the abundance of largemouth bass and could attract more anglers to the region, providing a boost to the regional economy. A delta in the upper end of Lewis and Clark Lake developed rapidly after the closure of Gavins Point Dam in 1955, as sediment from the Niobrara River was prevented from moving downstream (Johnson, 2002). The aggradation has increased the local flood stage, resulting in flooding on

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The Missouri River Ecosystem: Exploring the Prospects for Recovery private land. Hydropower head has been compromised more quickly than expected. Alternatives for eliminating the sediment have ranged from dredge removal to a pipeline for transporting the soil to the waters directly below Gavins Point Dam. However, one possibly useful measure to move the sediment may be a “run-of-the-river” management plan. The lake could be drained in late fall, and the river would be allowed to cut through the delta throughout the winter and until early spring each year. The soft, easily-eroded sediment in the bed of Lewis and Clark Lake would likely erode in both vertical and horizontal dimensions, and be transported as the river meandered across this otherwise lake environment (similar actions have been enacted for over forty years at Spencer hydropower dam in Nebraska; see Hesse and Newcomb, 1982). An appropriately timed spring release from Fort Randall Dam would provide a small spring rise to Segments 10 and 11. This rise could be captured downstream by Gavins Point Dam and would serve to refill Lewis and Clark Lake for the following spring, summer, and fall. A sluice gate may be required at Gavins Point to facilitate downcutting of the transported sediment. Additional sediment would move downstream and could help restore the sediment balance in Segment 13. Segment 13 includes an unchannelized reach from Yankton, South Dakota, to Ponca State Park in Nebraska. The segment has been impacted by the elimination of effective and base flows, by severe channel incision associated with sediment imbalance, and by selective bank stabilization. Few backwaters or islands exist along this reach. The segment was designated the Missouri National Recreational River in 1978, but development of a final general management plan was not completed until 1998. The National Park Service should incorporate recovery of riverine processes into the resource management plan (and the general management plan if necessary) that will be developed during the next few years. Much of the floodplain along this reach is agricultural land, but floodplain housing and recreational development are more extensive than in Segments 10 and 11. However, there are no large cities situated on the floodplain near the channel in this segment, with the exception of Yankton, South Dakota. Yankton is located on the Missouri River’s left bank and is the first community below Gavins Point Dam. The riverfront in Yankton is about one mile long. Much of the river bank there is armored and there has been significant channel incision (as much as fourteen feet). The channel thus has a huge storage capacity (which exceeds the discharge of prospective releases from Gavins Point Dam) and the river bank could be fortified to ensure protection to the city if experimental flows are conducted. Segment 13 (Gavins Point Dam to Ponca, Nebraska) would benefit ecologically with the recovery of some active meandering. Lateral sediment supplies would be engaged and sandbar development would be enhanced.

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The Missouri River Ecosystem: Exploring the Prospects for Recovery Pioneer cottonwood and willow communities would develop within the erosion zone on newly formed point bars. Primary energy supplies and turbidity would increase. Conveyance would be reduced, which would restore particulate organic matter in the hyporheic zone. Decreased conveyance would contribute to reduced flood stages downstream and would facilitate adoption of a programmed spring rise from Gavins Point Dam. The Wildlife Division of the Nebraska Game and Parks Commission is currently exploring opportunities to purchase lands from floodplain property owners willing to sell, and there are prospects for a sloughing easement program. In this latter program, private landowners are paid to allow river banks to erode. This would provide a demonstration project for restoring the action of meandering within several large bends of the river (Clayton Stalling, Nebraska Game and Parks Commission, personal communication, 2000). This segment contains an ecologically-important remnant population of paddlefish, sturgeon, and sauger that would likely increase in abundance with the restoration of flows that contained some of the river’s pre-regulation character. Commercial fishing for non-game fishes is still practiced in this reach, but the abundance of fishes, and thus the catch, is low. Commerical catfishing was closed in this segment and on the next upstream segment in the early 1990s. Catfish, buffalo species, and a more economically viable commercial fishery could develop here in connection with enhancements in river ecology. Segment 14 is the stabilized section between Ponca State Park and the confluence of the Missouri with the Big Sioux River. The segment was impacted by construction of channel-training structures, including stone hardpoints and revetments, by elimination of effective and base flows, and by extreme channel incision associated with sediment imbalance. This segment is a transition between the unchannelized condition of Segment 13 and the channelized portion of Segment 14. The original intent was to extend the navigable channel upstream to Yankton, South Dakota, but the project was never completed and commercial barge traffic does not extend into this stabilized reach of the Missouri River. Housing developments are common along the banks in this segment. Most houses are single-family dwellings used seasonally for river-related recreation. Nevertheless, there are opportunities to realign the controlling rock revetments to add 1,000 or more feet to the river’s top-width. Mid-channel bars exist in this segment, but they are exposed only during low flows. Substantially increased top-width would provide for exposed sand bars and island development. More sand bars would almost certainly result in more paddlefish, sturgeon, sauger, and waterfowl, including the federally-endangered least tern and piping plover. Segment 15 is the channelized reach between Dakota City, Nebraska, and Blair, Nebraska. The segment contains rock hardpoints, revetments,

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The Missouri River Ecosystem: Exploring the Prospects for Recovery and chute closure structures, has experienced the elimination of effective and base flows, and sediment imbalance has resulted in channel incision. During normal navigation and nonnavigation season flows, nearly all features of the original river cross-section are disconnected, including side channels and backwaters, and there are only a few sand bars. The pre-regulation channel and erosion zone was as wide as 6,000 feet. The same zone today is 600 feet wide. Experimental reconnection of cut-off side channels is not feasible upstream from about the middle of this segment because of the degraded channel. Although there are facilities in this segment that require continued bank protection— such as rail and barge facilities, power plants and industrial parks, and bridge abutments—the majority of the bankline and the immediate floodplain is agricultural. The only city is Sioux City, Iowa, which lies upstream from the designated beginning of the segment. An increase in the Missouri River’s top-width has the potential to initiate ecosystem improvements, and this could be achieved through eliminating or lowering channel and grade control. Stabilized widths of the Missouri River channel currently range from 600 feet at Sioux City, Iowa, widening as one moves downstream, to 1,100 feet at St. Louis (Slizeski et al., 1982). Modeling investigations have demonstrated that widening the Missouri River channel downstream from Sioux City, by 400 feet would “virtually eliminate further bed degradation” (Holly and Ettema, 1993). Relations between increased top-width and enhanced biological diversity and production must be determined through careful experimentation and monitoring, but the evidence at hand suggests a starting top-width of roughly 1,100 feet. However, top-width might be increased to several thousand feet at sites like Omadi, Snyder, Glovers Point, Winnebago, Black-bird, Tieville, Middle Decatur, Lower Decatur, Louisville, Bullard, Soldiers, Tyson, and California bends. Most of these floodplain depressions lie directly adjacent to the present navigation channel. Land in some of these sites has already been acquired under the existing authority of the Missouri River Bank Stabilization and Navigation Mitigation Project or under Section 1135 of various Water Resources Development Acts. Increased top-width throughout this extensive segment could provide a substantial increase in available flood storage. Additional storage would reduce downstream flood stages during high flows and would therefore make it less problematic to release a spring rise from Gavins Point Dam. Extensive sand bar, island, backwater, and riparian habitats would develop in this segment. Pioneer cottonwood and willow and riparian wetlands would benefit many native fish and wildlife species and enhance currently dwindling plant biodiversity on the floodplain. This entire segment (not just selected bends) could be widened while simultaneously protecting important infrastructure.

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The Missouri River Ecosystem: Exploring the Prospects for Recovery The potential to enhance the abundance of native fishes is great in this segment, as the transformation of native habitat by human actions is as great here as in any other segment on the Missouri River. More importantly, this segment and the next downstream segment (segment 16) are adjacent to densely-populated parts of several bordering states. The demand for additional recreational destinations near urban centers is great. Significant enhancements in river ecology would likely result in marked increases in user-days for recreational fishing, commercial fishing, and hunting. Moreover, additional sand bars would provide excellent opportunities for swimming, camping, and other leisure activities. Segments 16 through 19 include the channelized reach downstream from the Platte River in Nebraska to the Mississippi River. A two-tiered approach is one promising course of action for ecological recovery in these channelized segments. First, land riverward of the federal levees could be available for seasonal flooding each year. The federal levee system begins north of Eppley Airfield (Omaha) at about river mile 625 (upstream from St. Louis). This system was designed to protect farmland and developments landward—not riverward—of the levee. However, the land between federal levees and the river has been farmed, and expectations consequently arose to protect this land as well as those lands behind the levees. A programmed flood designed only to impact land riverward of federal levees is possible (Hesse, 1995). Navigation would be largely unaffected with this approach, at least upstream to Omaha. Second, site-specific alteration to the spur dikes and revetments along this reach may be accomplished to increase top-width on a smaller scale than would be implemented in Segment 15. Recent modeling has determined that top-width may be increased at least 175 feet without jeopardizing navigation (USACE, 1999). However, this modeling was done for the Lower Decatur Bend reach where periodic grounding has occurred. Other subreaches downstream from Omaha, where cross-section depth is greater than necessary to support full-service navigation, may be widened by more than 175 feet without impacting navigation. The navigation channel could be widened to the maximum allowable extent throughout the entire segment while maintaining a functional navigation thalweg. These hypothetical changes would entail tradeoffs, and compromises will be necessary; navigation upstream from Blair, Nebraska, may occur only during limited time periods or not at all, but navigation downstream of Omaha would not be impacted. Floodplain landowners and developers would be asked to accept permanent sloughing easements or flood easements in order to provide the necessary corridor to maintain a new, smaller floodplain within which the Missouri River would be allowed to meander (Box 6.1 describes efforts to create and expand the Big Muddy Wildlife Refuge in this stretch of the river). This would result in cut-and-fill

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The Missouri River Ecosystem: Exploring the Prospects for Recovery Box 6.1 The Big Muddy National Fish and Wildlife Refuge The Big Muddy National Fish and Wildlife Refuge in the State of Missouri was established on September 9, 1994, “for the development, advancement, management, conservation, and protection of fish and wildlife resources” (16 U.S.C. 742f(a)(4)). As of 1999, the refuge contained 16,628 acres. The U.S. Fish and Wildlife Service has proposed expanding the refuge to cover 60,000 acres, through acquisitions from willing sellers and donors, to help reconnect the river and floodplain and to assist in the recovery of species and habitat. The Missouri River floodplain covers approximately 800,000 acres in the State of Missouri. Natural resource managers in the region judge that between 10 percent and 20 percent of floodplain habitat must be “restored to insure long-term health of the Missouri River ecosystem” (USFWS, 1999). If fully implemented, the 60,000 acres of Big Muddy would be added to similar efforts by the Corps of Engineers (14,600 acres) and the Missouri Department of Conservation (20,000 acres). The total average would constitute about 12 percent of the 800,000-acre floodplain. The Missouri River floodplain in the State of Missouri has seen significant changes since settlement by the first Europeans over 200 years ago. Since the early nineteenth century, floodplain forest has been reduced from 76 percent of floodplain vegetation to 13 percent in 1972. During the same period, croplands increased from 18 percent to 83 percent of the floodplain. Agriculture’s dominance in the floodplain suggests that the number of future willing sellers and donors will be a function of national and global grain markets, federal support for agriculture, and perhaps the severity of future floods. Efforts to expand the Big Muddy face some of the economic, physical, and social constraints described in this report. The Fish and Wildlife Service’s Final Environmental Impact Statement (USFWS, 1999) describes how floods and flood damage reduction strategies have affected their efforts: “The Great Flood of 1993 provided the impetus to revive the concept. Flood damages prompted many bottomland farmers to consider selling their land so they could either retire from farming or relocate their operations. . . . By 1996 many landowners and drainage districts were actively repairing damages and reclaiming flood devastated lands, even after a near repeat of the 1993 flood in 1995. By early 1997 landowner interests in ’selling out’ had begun to wane. By the time the draft of this document was available for public review in October 1997, some landowner and private property rights groups had labeled this project a ’government land grab’.” alluviation and many features similar to those of the pre-regulation Missouri River, while other portions could be maintained much as they appear today. It should be possible to improve Missouri River ecology by effectively widening the river and floodplain ecosystem by a few thousand feet in select areas. The same values would accrue to these downstream segments as in river segments just upstream. There are unmet demands for public fishing and hunting opportunities in and around urban centers like Kansas City,

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The Missouri River Ecosystem: Exploring the Prospects for Recovery Omaha, and Saint Joseph, Missouri. As demonstrated in recreational surveys over the past few decades (Groen and Schmulbach, 1978; Mestl, 2001; Zuerlein, 1984), the Missouri River has great potential to become an important and economically valuable tourist destination. CHANGING MISSOURI RIVER OPERATIONS Legal Considerations The issue of the Corps of Engineers’ legal discretion to implement adaptive management strategies is complicated. Clearly, the Corps has no express duty to practice adaptive management—the concept is relatively new and did not exist when the Pick–Sloan Plan and subsequent legislation were adopted. Nor has the Corps been directed by Congress to implement specific adaptive management actions on the Missouri River. However, the lack of express authority to practice adaptive management does not preclude the Corps from implementing adaptive management actions ancillary to their general management authorities or pursuant to the protection of endangered species. In fact, and to the Corps’ credit, the agency intends to release experimental flows from Fort Peck Dam. In addition, despite different legal contexts, ongoing restoration efforts such as those in the Columbia River basin, in the Florida Everglades, and on the Kissimmee River provide useful precedents for the Corps. The Corps has seemingly taken inconsistent positions on its legal management authority. At times, it has claimed that the agency’s legal flood-control and navigation enhancement duties, as defined in the Master Manual, leave it with limited discretion to experiment with different flow regimes. The Master Manual is, however, only a self-imposed limitation on its discretion. When its management authority has been challenged, it has taken the position that it has the legal discretion, virtually beyond review, to operate the reservoirs to balance among the competing multiple uses of the Missouri River. This claim is grounded in the Pick–Sloan Plan and subsequent legislation. As previously mentioned, the flows of the Missouri River are unallocated between the basin states and no states or individual parties have firm entitlements to any set release plan. There is no right to flood-control protection or to a minimum navigation flow, such as would exist within an interstate compact entitlement. This suggests that the Corps has considerable legal discretion to operate the system more flexibly than in the past. For example, in South Dakota’s 1989 challenge to the Corps’ failure to maintain high water levels at Lake Oahe, the Corps characterized the Master Manual as a non-binding “Guidance Document.” Using this approach, fish and wildlife enhancement through adaptive management is a choice open to the Corps.

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The Missouri River Ecosystem: Exploring the Prospects for Recovery The Corps could not and should not make decisions that ignore its flood-damage reduction responsibilities. However, this committee did not find an irrevocable conflict between efforts at Missouri River ecosystem restoration and downstream flood damage reduction for urban areas at risk from floods. As adaptive management actions are implemented, great sensitivity must be shown to those most at risk from changed operations and a wide range of creative risk minimization options should be explored at all stages of the process. Current project beneficiaries may raise legal objections to any change in the operation of the system, but the ultimate success of these objections is not guaranteed. For example, beneficiaries of navigation flows do not have rights to any natural or artificial flows of the Missouri River. The “navigation servitude” posits that no individual may assert a property right to the flow of a navigable stream below the high water mark of the stream. The assumption has long been that the government may enhance or destroy the navigable capacity of a stream. Thus, the only navigation flow entitlement that could arise would be a by-product of a lawsuit alleging that the Corps acted without authority in the operation of a reservoir. The Supreme Court has given the Corps great discretion in operating the Missouri River’s Pick–Sloan dams. The status of navigation is further complicated by the 1944 O’Mahoney–Millikin compromise. The upper basin states maintain that the language of O’Mahoney–Milliken subordinates navigation to irrigation and precludes the recognition of any vested rights for a navigation channel depth. At a minimum, the compromise has long put lower basin states on notice that they face the prospect of diminished flows. As pointed out in a June 20, 2000 memorandum from the Congressional Research Service, the statute does not mandate any fixed navigation season and navigation is only one of several multiple uses for which the reservoirs are managed. The O’Mahoney–Millikin amendment contemplated that navigation would be subordinate to future irrigation withdrawals. Some operational changes may increase the risk of downstream flooding. The legal issue is primarily whether the federal government is liable for property damages that result from intentional flooding. The federal government is not liable for “Acts of God” and Congress has enacted legislation that immunizes the federal government from all liability for damages arising from the operation of multiple purpose reservoirs for purposes related to flood control (33 U.S.C. Section 703c). However, if the government permanently inundates land above the high water mark in connection with a flood damage reduction project, the government must compensate the landowner because the servitude only extends to the high water mark. The fact that reservoir operations have non-flood control-related purposes does not deprive the government of its immunity so long as flood control is

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The Missouri River Ecosystem: Exploring the Prospects for Recovery a purpose. However, as discussed in Chapter 2, if the Corps operates the reservoirs for a purpose unrelated to flood-damage reduction and causes flood damages, the government’s immunity does not apply (Central Green Co. v. United States, 531 U.S.C., 2001). Congress always has the option to waive the government’s immunity and compensate those injured by releases. Legal objections to changed operations are further complicated because the Corps must subordinate dam operations to the protection of listed threatened and endangered species. The Endangered Species Act and most other environmental legislation were enacted after the Pick–Sloan Plan, and the usual legal presumption is that later acts modify prior acts. The courts have repeatedly held that the Endangered Species Act imposes a duty on the dam operating agency to comply with the mandates of the Act. Exceptions are made only if Congress specifically exempts the project or activity, or the agency obtains an endangered species exemption (Tennessee Valley Authority v. Hill, 437 U.S. 153, 1976; Klamath Water Users Protective Association v. Patterson, 191 F.3d 1115, 9th Cir., 1999). Tradeoffs in Missouri River Management Decisions A portion of the Missouri River’s pre-regulation physical processes must be restored if the ecosystem’s conditions are to improve. This will require changes to reservoir release schedules. Identifying tradeoffs that must be made to initiate these changes is a first step toward understanding how those changes may impact stakeholders. The following section provides examples of necessary tradeoffs to improve Missouri River ecology. Ecosystem Services Most tradeoff decisions regarding Missouri River management and dam operations relate to enhancing flows of ecosystem goods and services, which include a greater variety of wildlife of all kinds, including plants, increases in the production of rare and endangered species, and maintaining and improving production (e.g., fisheries, wildlife habitat) from wetlands and riparian areas. Although not always easily commensurable with the monetized values provided by the Missouri River ecosystem, such as navigation and hydroelectric power, many ecosystem services have great value. The values provided by these services, and the values that were lost with increasing Missouri River regulation in the 1950s and 1960s, have historically received limited attention in Missouri River reservoir management decisions. However, the enhancement of the Missouri River ecosystem may ultimately provide a broader and more sustainable set of benefits to the region and the nation than the current purposes for which the river is

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The Missouri River Ecosystem: Exploring the Prospects for Recovery managed. The tradeoffs necessitated by changes in river management may even result in heretofore unanticipated benefits, while the costs of these tradeoffs can be reasonably well understood at present. Floodplain Infrastructure and Residents Over the years, the Missouri floodplains have become the site of agriculture, homes, businesses, and infrastructure that supports many large and small communities. Much of this development replaced fish and wildlife habitat. In many areas, ecologically-valuable wetlands have been isolated from river flows and separated from the river ecosystem by channel works and levees. Some reconnection between the river and its floodplain is a key element in restoring ecological benefits. The Corps of Engineers has made efforts in its mitigation and restoration activities to carry out such reconnections; however, considerably more effort will be required to effect significant ecological improvements. Restoration activities accomplished to date have been done with the cooperation of landowners who have voluntarily agreed to sell land or have provided necessary easements. Future restoration efforts must recognize the necessity to work closely with floodplain residents to both minimize their vulnerability to floods and to ensure appropriate compensation for damages they might sustain or for property used in restoration efforts. During the twentieth century, the prevailing aim of the nation’s floodplain management policy was to reduce flood damages, primarily through levees, the upstream retention of water in reservoirs, and other structural measures. However, it has been recommended that a more appropriate goal is to maximize social benefits from our floodplains (NRC, 2000b; White, 2000). This latter goal discourages the location in the floodplain of new structures that are vulnerable to flood damage and encourages, where appropriate, the relocation from the floodplain of structures and activities that have been repeatedly damaged or are at high risk. Since the Mississippi flood of 1993, there have been roughly 13,000 voluntary property buyouts in the Mississippi and Missouri river basins (Michael Robinson, Federal Emergency Management Agency, personal communication, 2001). A variety of mitigation measures can help people cope with flood damages. Floodproofing techniques, such as raising buildings or placing critical infrastructure above the first floor, are common and can greatly reduce flood damages. Flood insurance available through the National Flood Insurance Program (administered by the Federal Emergency Management Agency) is also available to some floodplain residents. Relocation may represent a viable option in some instances. Displacement of people and infrastructure from floodplains must be conducted very

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The Missouri River Ecosystem: Exploring the Prospects for Recovery carefully, as it may entail significant monetary and psychological costs. The process should be viewed as an opportunity to enhance social benefits from the floodplains, and a goal should be to assure that relocations make people at least as well off as they were before relocation. The costs of displacing people and infrastructure must be balanced against considerations such as the nature of the activity (farming and ranching; housing; industry) to be relocated. For some activities, location on the floodplain is essential; but if activities can be conducted elsewhere, relocation is a possibility. Voluntary relocation of floodplain structures has helped reduce federal payouts for flooded properties and infrastructure not covered by federal flood insurance. Navigation and Changes in River Flows The future of navigation on the channelized portion of the Missouri River represents a political challenge, as tradeoffs are likely necessary between maintaining full navigation service and reconnecting the river channel with its floodplain by changing flows at select times of the year. The economic consequences of tradeoffs between flow regimes, channel maintenance and recovery, and navigation are likely to be modest; however, this has nonetheless proven to be a politically contentious aspect of Missouri River management. COMMITTEE COMMENTARY The Missouri River, its floodplain, and its mainstem reservoir system provide many benefits, many of which are complementary. For example, reducing navigation flows to enhance ecosystem benefits may increase reservoir levels and lead to greater hydropower and recreation benefits. On the other hand, some benefits are at odds with one another. For example, efforts to restore natural physical processes and ecosystems may require occasional high flows from mainstem reservoirs that increase flooding and interfere with agricultural drainage. When the dams and reservoirs were constructed, it was felt that these structures were changing the river system for the benefit of society. Menacing floods would be reduced or eliminated, navigation would be enhanced, irrigation waters would be stored, and hydroelectricity would be produced. There were costs at the time, but many of these were nonmarket costs and were seen as the price of progress. Environmental changes were viewed by some as being positive. The opinion that engineering structures would greatly reduce the ecosystem’s benefits was expressed by a relatively small number of people. But over time, scientific understanding of the ecosystem and the impacts of human actions on the environment, as well as knowl-

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The Missouri River Ecosystem: Exploring the Prospects for Recovery edge of the social benefits of environmental goods and services, have broadened and become more sophisticated. Social preferences have shifted greatly in the Missouri River basin over the past fifty years. The management regime of the dams and reservoirs, however, has been slow and more resistant to changes. Agencies responsible for operating the dam and reservoir system have attempted to appropriately adjust operations schedules, but have been caught between opposing stakeholder groups and have thus been limited in their ability to do so. No one knows exactly what types of management actions must be enacted in order to restore socially-desirable levels of ecosystem benefits. But if further declines in the Missouri River ecosystem are to be halted and reversed, the time for implementing management actions aimed at ecosystem restoration is at hand. This chapter describes dozens of examples of prospective management actions that would improve ecological conditions. Details of those actions should be designed by citizens, scientists, and management agencies. They will necessitate trade-offs between stakeholders. Outcomes of these actions should be carefully monitored. Many actions will be conducted locally, but they should be coordinated in framework that considers all actions throughout the Missouri River ecosystem. They should not be seen as fixed policies, but rather as experiments that can be scaled back if results are disappointing, or enhanced if results are promising. In implementing management changes, there will be setbacks as well as pleasant surprises. Stakeholder cooperation in this setting presents a challenge, but it is essential if further declines in the ecosystem are to be averted. This report’s final chapter provides advice on establishing and sustaining a multiple stakeholder group for Missouri River management.