A Watershed Assessment for the Siuslaw Basin
Siuslaw Basin Physical and Cultural Geography
The 504,000-acre (773 square mile) Siuslaw River Basin is located on the Central Oregon Coast (see Map 1.1). It stretches from Lorane Valley and Low Pass in the east through the Coast Mountain Range to Florence, the Dunes, and the Pacific Ocean in the west, an "as-the-crow-flies" distance of about 50 miles, but a river distance of nearly 120. Mountain ridges on the north and south separate the Siuslaw from the Alsea and Smith Rivers. Near the coast, low dunal hills separate the Siuslaw from several small, self-contained lake basins. The east edge of the basin is separated from Willamette River tributaries by a north-northwest to southeast trending ridgeline.
There are three distinct geographic parts to the Basin. First, in the east the landforms and settlement patterns are similar to the Southern Willamette Valley. Low, rounded hills frame broad, nearly level valleys that historically had prairie vegetation, still evident when the camas (historically an Indian staple) is in bloom in early spring. Oak and pine edge the valleys, giving way to Douglas and grand fir on cool, north facing slopes. Riparian woodlands are characterized by Douglas and grand firs, black cottonwood, and Oregon ash trees. Farms are relatively large and diverse, with new wineries overlooking the landscape. Lorane Valley and Upper Lake Creek basin characterize this part of the watershed.
As one travels west, the valleys narrow, the hills become steep mountains, and the ridges are more knife-edged than rounded. This is the Coast Mountain Range, and it covers the great majority of the total land area of the basin. Farms hug narrow valley floors. Homes are clustered along stream junctions. Roads wind along with the creeks. The forest crowds open areas, but numerous clearcuts are a significant part of the landscape mosaic. Forests are for the most part fairly young, with "old growth" stands only occasionally seen. The pattern of logging in the eastern half of the Basin reflects the "checkerboard" land ownership, a long-lived echo from the Oregon and California Railroad land grant. In the western half, most of the uplands are within the Siuslaw National Forest, with scattered in-holdings of private, industrial forestland. The valley floors are mostly small farms and homesteads.
West of Mapleton, where State Highways 36 and 126 come together, the Siuslaw River becomes very wide, with a broad floodplain, numerous wetlands, and tidal islands. This is the estuary, which leads to the dunes along the coastal plain at Florence. Here the land is characterized by barren sand dunes interspersed with pine woodlands and deflation plain lakes or wetlands. The wind picks up, the air feels different, and most residents make their living off of retirement pensions or tourists rather than from the harvest of trees, crops, or fish.
The ecology of the Siuslaw Basin landscape is complex, and reflects the interaction of climate, geology, landforms, natural vegetation, and land use. Most of the basin lies within the Coast Range Physiographic Province (Franklin and Dyrness). The underlying geology is almost entirely layered marine sandstones, known as the Tyee Formation. This is a soft, erodable rock that, when combined with the high seasonal rainfall and steep slopes is subject to landslides known as "debris flows". The overall shape of the land, with relatively level but narrow valleys flanked by steep low mountains with knife-edge ridges, is a result of this interaction. The Coast Range is still actively rising, but the main streams have the power to carve out low-gradient paths through the mountains to the sea. The Siuslaw is one of only a few rivers that has managed to cut a path entirely through the coast range.
While the coastal mountains have a clear north-south axis, numerous faults and joints establish more variable patterns of ridges and valleys. The southeastern part of the basin, from Lorane Valley to Whittaker Creek, has a decided east-west orientation. The northeastern quadrant orients northeast to southwest. In the western half of the basin, the valleys and ridges generally run more north-south, but are quite variable. This complex topography facilitates the flow of hot, dry air from the interior well into the Coast, while blocking the cool, moist air from penetrating very far inland (during the dry season).
There are five fairly distinct "geomorphic," or landform zones in the basin. First are the terraces and floodplains along the main streams, most notably; Upper Siuslaw/Lorane Valley, Lake Creek, Lower Siuslaw and the North Fork, and to a lesser extent Indian Creek, Deadwood, Sweet, and Wildcat Creeks. Since the valleys are wide enough in these places to retain alluvial deposits, they have been the most suitable for settlement, farming, and transportation corridors. Second, the gently to moderate sloping hills in the eastern quarter of the basin. These have rounded shapes, low stream density, and fairly deep soils. They feel more like "foothills" than mountains. The hills that frame Lorane Valley are entirely volcanic in origin, and are geologically related more to the Cascades than to the Coast Range.
Third, there are infrequent but important volcanic formations that break through the coastal sandstones. The volcanics are harder, more resistant rocks, thus they form the upper ridges of the highest mountains (i.e. Roman Nose, Prairie Peak, and Walker Point). Fourth, the most dominant in terms of area and processes are the sharp-ridged, steep sloped heart of the Coast Range. This is where the sandstones are at the surface. Erosion rates are high, and debris torrents a major force in shaping the landscape. Fifth and last is the coastal terrace at and around Florence.
There are two interesting anomalies to the basic geomorphology of the Basin. The first of these are Triangle and Esmond Lakes, which formed as a result of large debris flows during ice age times. In a basin with very few lakes, Triangle is quite intriguing, one of the largest in the Coast Range. The second anomaly is Lorane Valley. Ecologically, this area is much more like the Willamette Valley than the Coast Range. In fact, it is believed that the Valley used to drain to the Willamette. A very low divide sends water south and west instead of north.
The hot, dry summers in the east created a fire-prone vegetation community and pattern. Indians frequently burned the prairies and oak woodlands to facilitate hunting and food gathering (Boyd). On occasion, these fires from the east were (and still are) pushed west by strong late summer or early fall winds. The denser forests of the coastal mountains burn less frequently than the valley woodlands, thus fuels have more time to build up, and when fires arrive they are more intense, replacing stands over wide areas. Sitka spruce forests along the coast burn rarely, with wind disturbance more important as the way in which stands are naturally cleared and regenerated (Agee). Much of the basin burned heavily in the mid-nineteenth century, resulting in large areas of brush-covered hills. The valley bottoms and north facing slopes were generally too wet to burn hot, so forests in these areas were able to develop over a longer period. But the valley forests were subject to frequent flooding, beaver activity, and patch burning of open meadows by Siuslaw Indians. Ridgelines may also have been deliberately burned to facilitate travel and hunting.
The western, coastal fog line reaches east up the main stream valleys, allowing sitka spruce to grow inland as far as the north fork of Indian Creek. Western hemlock grows with the spruce, but is joined by Douglas fir at about the place where the spruce stops its penetration. Because of fire and logging history, Douglas fir is by far the dominant tree in most of the basin. The valley floors were a mixture of old growth cedar, maple, and alder groves interspersed with wetlands and swamps before they were cleared and drained by early loggers and farmers. Huge logjams gathered along the lower valleys. Early visitors recorded old growth cedar trees growing on top of logjams at the mouth of the North Fork (McLeod). They also noted many large, downed trees that made travel very difficult. The beach and estuary collected large amounts of driftwood (Maser).
The mountain ridges are low enough that snow pack does not persist beyond a few weeks. Forests drape right over the tops of the hills, and there is no true alpine vegetation. There are a few "grass balds" such as those at Prairie Mountain. Erosion rates are highest in the middle part of the basin, where the mountains are steepest and rainfall highest.
The natural vegetation composition and structure of the basin has been significantly altered by Euro-American settlement. Valley bottom prairies, wetlands, and riparian forests have been converted to pasture, cropland, and homesteads. Much of the upland forest has been clearcut at least once, and in some cases converted to plantations that are now logged and regenerated on a 40–60 year cycle. Introduced species have spread and altered the ecology of the area. These include: pasture grasses, scotch broom, European beach grass, gorse, Himalayan blackberry, and spartina grass (in the estuary).
Prior to Euro-American settlement, the forest had significantly more old growth and mature forest than it does now. Old growth for the Coast Range Province is estimated to have ranged between 25–75% over the past 3,000 years (Wimberly). Fires in the eastern part of the basin were fairly regular, resulting in areas of open forest, and a "patchy" mosaic of young, middle-aged, and older stands. In the western part, fires were less frequent, but burned much larger areas. Forest age and composition was fairly uniform over wide areas, averaging 10,000 acres in size. Older forests would have had small gaps in the canopy caused by disease pockets and windthrow. The last major fire occurred in the 1840s, and burned a large part of what is now Siuslaw National Forest land. There were also a number of moderate sized fires in the early to mid 20th century. The most recent fire burned several hundred acres of private forestland west of Whitaker Creek a few years ago.
The lack of snowpack, steep terrain, low gradient streams, shallow soils, relative dryness in the east, and absence of a true "headwaters" conspire to create a naturally "flashy" stream system, with unpredictable and highly variable flows. The first heavy rains of autumn are only partly absorbed into the dry, porous sandstone soils. Streams rise quickly once the rains return, then dry to a trickle by mid summer. The land has limited ability to store water, and what natural ability it does have has been compromised by logging, road construction, valley clearing, wetland draining, removal of logjams and resulting stream downcutting. This has important effects on the aquatic system, as will be discussed later on.
Rainfall is much higher in the western part of the basin than in the eastern part. This, combined with the pattern of seasonal rain, also limits the amount of water available to streams in the summer. Relatively very little is generated or stored in the upper watershed (Armantrout 1).
Historically the low gradient stream system contributed to frequent flooding of the valleys. It was likely winter or spring floods, stored in the valley wetlands, were crucial to maintaining base flows in the summer. As streams have cut down and lost contact with adjacent floodplains, and wetlands drained, the aquatic system has in turn declined (Westfall).
Aquatic conservation issues
The Siuslaw River Basin has been the subject of many studies and much interest with regards to the aquatic ecosystem over the past few years. The basic story is well known by most of those who have taken an active interest in the watershed.
Historically, the Siuslaw Basin was one of the most abundant anadromous fish producers in the Pacific Northwest. The combination of geology, climate, forest development, and lifeways of the Siuslaw Indians established and maintained a system where salmon and the people who depended on them flourished for many years. Archeological records indicate that salmon "arrived" in the basin in abundance about 3,000–4,000 years ago. The evidence is in midden sites that show the diet of the Native people shifted to salmon at about that time. This corresponds roughly to a general cooling of the climate, which likely established conditions more favorable to salmon, and allowed them to extend their range south.
Early cannery records indicate that the Siuslaw was second only to the Columbia River in numbers of coho. The average coho numbers from 1889–1896 were 209,000 fish (Booker). This compares to an average of just over 3,000 in the years 1990–1995. Why have the numbers declined to such an extent?
There are some factors that have affected salmon in other watersheds that we can rule out. Unlike many other river systems in the Northwest, there were no large dams built in the Siuslaw basin. There are only a few small dams in upper reaches that form mill ponds. The basin has not been heavily urbanized or extensively farmed. There are farms to be sure, but the percentage of land in agriculture and urban areas is very small compared to most Northwest River systems.
Two significant activities that likely affected the salmon did happen however. The first of these was the simple fact of over-fishing. The Siuslaw Indian population was relatively low. The most reliable early estimate indicates that 900–2,100 Indians were present in the Basin at the first recorded contact with Euro-Americans (Booker). These numbers may have been unusually low due to diseases that preceded settlement. Nevertheless, the Siuslawans had an economy and social structure, similar to that of most Pacific tribes, that insured that enough salmon would reach spawning grounds each year to perpetuate an abundant population. In addition, they did not heavily alter the basic ecology of the land. They did not clear logjams, practice agriculture (though camas collection did border on becoming agriculture in some areas,) or engage in large scale logging. They also did not build roads and railroads. They did harvest plants and cut trees, particularly the western red cedar. But their harvest style was to split planks for homes off of live trees. Whole tree harvest, primarily for canoes, was selective and rare. We know that their exploitation of the salmon and other resources proved to be sustainable over hundreds, and perhaps thousands of years.
Early Euro-American settlers saw the salmon as more of an economic resource than as a purely subsistence one. In an era of unregulated harvest, the first one that caught the most gained the rewards. In 1875 the few Siuslaw Indians who had managed to survive diseases introduced by initial contact lost their legal battle to retain the entire basin as their reservation. This opened the area to pioneer settlement. The first salmon cannery opened at the site of Florence in 1876. Other canneries followed, and Chinese laborers were imported to provide the labor. From 1887–1892 over 68,000 cases of Siuslaw caught salmon were packed and shipped to markets in Portland or San Francisco (Booker).
While the salmon were now harvested in numbers far beyond what the Indians likely had taken, the valleys were being cleared for settlement. The first farms located in the far east of the basin, near Lorane and in upper Lake Creek. These were extensions of Willamette Valley settlement patterns. Prairies and oak woodlands were transformed into grazing or crop production, depending on how wet or fertile the soil. Land claims also began working their way upstream from the river mouth in the late 1870s. The first of these were near the head of tidewater, near Mapleton. By 1882 all the farmable land up to tidewater was claimed. By 1893 Florence was platted as a town site. And by 1894 land was claimed along all the main tributaries of the Siuslaw (Karnes).
The early pioneers lacked modern power tools, but still cleared the valley forest and logjams as best as they could. A sawmill opened in Florence in 1879. In the absence of roads or rail lines, "splash dams" were used to drive logs to the estuary. These were temporary log crib structures that backed up water and logs for some distance up stream. Some were then dynamited out to release a torrent that carried the logs downstream. Others were released in a more controlled fashion, and used repeatedly. One unintended result was scouring of the creek bottoms to bedrock. Another was the loss of natural logjams. Deep pools were lost, and the streams became increasingly channelized.
As the valley bottoms were logged and drained, and the streams scoured out, the aquatic ecosystem lost much of its ability to store water, sediment, and nutrients. The river network that had been so hospitable to salmon and other aquatic wildlife functioned more like modern urban streams, in that they funneled water quickly downstream.
By 1893 these cumulative impacts had driven the numbers of salmon downwards. To compensate, a hatchery was built at Mapleton, but it only operated for five years. Surplus fish from hatcheries outside of the basin continued to be released annually from 1964 to 1988 (Booker).
A jetty was completed at the Siuslaw mouth in 1918. This project helped get larger ships more safely in and out of the harbor. In combination with completion of a railroad connection to the Willamette Valley in 1914, the basin was now available for industrial scale logging. But the technology of the time still limited logging to valley bottoms and lower slopes. It was not until after World War Two that hillside logging really got under way. Extensive road systems were constructed. Many roads were built on steep side slopes, with little regard to stability. One result was an increase in the frequency and size of landslides, particularly debris flows. And where debris flows that carried large trees into streams were important contributors to the aquatic system, those that occurred after logging carried mostly sediment, which likely did more harm than good.
There were few regulations governing the practice of forestry on private lands until the State Forest Practice Act of 1972. Streams became choked with logging debris, leading to efforts on the part of state and federal biologists to "clean" them of slash. In many cases this led to over clearing, where large and small pieces of wood were removed to aid salmon passage, but at the expense of habitat and structural stability of streams.
Efforts to stabilize or improve aquatic habitat in the basin have been under way for many years. Gillnet licenses were required as early as 1899. The Oregon State Fish Commission began restricting river fishing intensity and methods in 1939. Commercial fishing was closed on the river in the 1950s. But the fishing pressure simply moved out into the open ocean. The last cannery in the basin closed in 1956, as numbers of returning salmon continued to decline. Even sport fishing for coho was closed in 1993 (Booker).
By the mid 1970s, private and public forest managers began constructing roads differently. They avoided "sidecast" methods that had proved unstable, and adopted full bench construction. The Northwest Forest Plan for federal lands, adopted in 1993, protected most of the National Forest and BLM lands from clearcut logging. Riparian buffers were greatly enlarged.
Most of those who have followed the issue of salmon in the Siuslaw Basin over the years now agree that the combination of over-fishing, loss of habitat, and poor ocean conditions in the 1980s and 1990s finally brought the entire situation to a head. The listing of coho as a threatened species in 1996 forced policy makers, resource managers, and local communities to try new approaches to aquatic conservation. The question now is not on how many fish we can catch, but whether the aquatic ecosystem can recover to a point where salmon can again be a sustainable resource. The essentials are clear. The basin ecosystem (including changes in the ocean) may have been changed to the point where it likely can no longer can support historic, or even reasonably high numbers of most salmonid species. One exception appears to be the chinook, which has recovered to nearly historic levels. There are two likely explanations for this. First, the chinook may have a greater reliance on the estuary, rather than the river system, as essential rearing habitat. Second, chinook juveniles rely on stream reaches only during late winter and spring seasons, when there is plenty of cool water. Their life history demands may be met during this period.
A summary of aquatic ecosystem issues
Bedrock and downcut stream beds
Significant reaches of mainstem and tributary sections appear to have been either "sluiced down to bedrock," or show visible evidence of down cutting. While scouring and downcutting can be a result of natural stream processes, the present extent is believed to be far greater than the historic occurrence. The main causes are believed to be clearing of log jams, logging of riparian areas, conversion of valley bottoms to farms or homesteads, increased frequency of debris flows, and scouring of channels by splash dams. No measurement of downcutting across the basin is available, but the BLM estimates that the Upper Siuslaw and its tributaries are between two to ten feet lower than they were historically (USDI 1996).
Degraded riparian habitat
Because the narrow valley bottoms are the only places in much of the watershed suited to agriculture, home building, and transportation corridors, and because these areas were the easiest to log initially, riparian forests and associated wetlands have born the brunt of the last 125 years of development. Only about 36% of the entire riparian zone (measured as 200' on either side of streams) is in mature or very mature forest condition at present. The extent of wetland loss is unknown, but is likely very high, particularly in farmed areas.
Loss of habitat complexity
The two factors above have combined to result in a simplification of the aquatic system. As stream channels become cut down into the landscape, they lose contact with floodplains and wetlands. Large wood, a keystone of the ecosystem, is no longer present in sufficient quantities, and the few pieces of wood that make it to the streams are quickly swept to the estuary and out to sea during winter storms. This is reflected in stream surveys conducted over the past 10 years by ODFW and the Forest Service, which identified a lack of large wood and "complex" pools (Willer).
Loss of food web support
The loss of complexity has resulted in a leaking of nutrients from the stream system. Salmon eat bugs that eat other bugs that eat vegetation. The vegetation is retained in the system by complex habitat, including floodplains, flats, and wetlands. Fish need foraging habitat to go along with spawning and rearing.
Loss of estuary habitat
About 58% of the original wetlands in the estuary below Mapleton have been diked or drained. Dredging of the channel, and the funneling effect of the jetty likely results in a leakage of wood and nutrients to the ocean. This may in turn limit the ability of salmonids to "fatten-up" before heading out to sea, thus reducing ocean survival. Most of the remaining wetlands in the estuary are privately owned and only partly protected from development. There are emerging opportunities to restore former tidal wetlands by removing dikes and tidegates.
Factors outside of the watershed
Fluctuating ocean conditions, predation of salmon at sea, and competition from hatchery fish are all factors affecting the year to year abundance of fish in the Siuslaw. Even if the watershed were in pristine condition, there would be good years and bad years. But with the populations reduced to a level far below that experienced at any time in the recorded past, there is little room for further habitat loss. The system has lost much of its resilience.
There are a number of social and cultural issues that also may be working against recovery of the aquatic ecosystem:
The settlement pattern and infrastructure is "fixed" in place
Recovery will have to happen without significant change to existing patterns of ownership and use of land, or to main transportation corridors. The checkerboard ownership of forest lands in the eastern half of the watershed presents a particular problem in coordinating protection and restoration efforts. Valley bottom settlement limits the potential for wetland and riparian restoration.
Lack of economic opportunity
The loss of fishing, and general decline in agriculture has been accompanied by a decline in forest related jobs. The amount of trees that can be cut each year has dropped, particularly on federal lands. Private, industrial forests are being cut on 40-60 year economic rotations that are less than optimal in terms of maintaining high harvest volumes. State forests are still at mostly young ages, and will be harvested at a fairly slow rate. Many local mills have closed. Others operate at lower levels than they had in the past. Wages of forest workers have stagnated or declined. The tourist/retirement economy in Florence is relatively strong, as is the diverse economy of the Eugene area. But service jobs typically pay less than ones in natural resources.
Continued logging and valley bottom farming
These combine to deprive the stream system of a steady supply of large wood that could rebuild complex habitat over time at relatively low cost. The legacy of large wood that formed the backbone of the aquatic habitat has mostly been lost, and there is not enough left in the landscape to replace it. In addition, continued logging of high risk debris flow areas disrupts the natural cycle of sediment and organic delivery to streams.
Natural resource economic pressures
The need to return profits on investment capital over relatively short time frames (in the life of a forest) makes long term retention or re-growth of mature forest on private lands problematic. Large industrial forest companies are compelled to harvest trees as soon as they become economically useful, in order to maintain adequate returns to investors, or just to keep mills operating to protect workers' jobs. In addition, the market for large logs has significantly diminished over the past few years. Family owned and managed forests often harvest trees less intensively, and practice alternative silviculture (such as uneven-aged forestry) that has lighter impact to the aquatic ecosystem.
Insufficient funding for watershed "restoration"
The total amount of public funding, at about $1.5 million per year, is small compared to the need, and spread between many agencies. The Siuslaw basin must compete with watersheds throughout the state and region that have equally great needs. Political support for maintenance or increase in funding levels is weak, particularly as the economy has slowed.
Staff cutbacks at federal and state agencies
The Forest Service, Bureau of Land management, National Resource Conservation Service, and Oregon Department of Fish and Wildlife have all experienced continued budget cuts over the past decade, resulting in gradual loss of local aquatic resource expertise. One example is the planned merger of the Siuslaw National Forest into the Willamette, which will result in closure of the Corvallis headquarters.
Restoring the aquatic ecosystem is a complex challenge
To our knowledge, no one has ever successfully restored a watershed the size of the Siuslaw. Reaching a level of watershed health where salmon will once again be abundant will likely take many years, require unequal sacrifices or efforts on the part of local land owners and taxpayers, and may be resisted by those who feel the burden on them is not fair or affordable.
Recent protection and restoration efforts
Natural resource managers from various agencies have been attempting to address habitat related issues in the Siuslaw Watershed since the late 1960s. The Bureau of Land Management began installing rock gabions in streams at that time, as a way to improve habitat (Armantrout 2). The Oregon Department of Fish and Wildlife began efforts to build a fish ladder at Lake Creek Falls in 1964, but this was not completed until the late 1980s. Streams were cleared of log jams and beaver dams in the mistaken belief that this would aid fish passage. Restoration efforts since the 1980s have focused on installing in-stream structures to help capture gravels, wood, and nutrients. Since the 1970s, midslope roads on federal lands have been built to higher standards, so that they will stay put on the hillsides.
In the 1990s, multiple efforts have grown. ODFW, the Forest Service, and BLM have continued to experiment with various techniques for improving in-stream structure and habitat. Many unneeded roads have been closed or "storm-proofed." Timber companies have worked to stabilize roads and replace problem culverts. Some valley-bottom landowners, particularly in Deadwood Creek, have restored wetlands and replanted or fenced riparian areas. Overall, the Watershed Council has distributed an estimated 25,000 trees to private landowners for riparian planting, resulting in about 20 miles of new streamside trees (Nichols). Parts of the estuary are planned to be restored to tidal wetlands. Florence has upgraded its sewage treatment plant, and is taking progressive steps at recharging its aquifer by directing stormwater into the ground. The Siuslaw Watershed Council is gradually building a "watershed community" that will ultimately improve stewardship from Lorane to Florence.
Most of the Federal land in the basin is now protected from clearcut logging (as a result of the Northwest Forest Plan,) and may eventually recover to mature forest condition. State forest management has been re-oriented to growing more mature forests. Combined federal and state spending on restoration is running at about 1.5 million dollars a year. In kind contributions of labor, machinery, and materials from private landowners may be matching or exceeding this amount (Westfall).
A recent study of Northwest coastal rivers by Ecotrust evaluated three parameters believed to be critical to restoration of aquatic ecosystems: (1) the historic carrying capacity of the system, (2) the potential for restoration based on the degree of human influences, and (3) the current aquatic production. Based on these criteria, the Siuslaw Basin received the highest ranking among all of Oregon's coastal watersheds. This study particularly reflects the high historic numbers of salmon, and that in spite of 130 years of intensive land use, the system remains free of large dams or urban areas, and is still mostly forested.
Some fishery managers believe the efforts of the past decade may have succeeded in "stabilizing the decline" (Armantrout 2, Westfall). Clearly a number of individuals, local communities, and agencies are working very hard to improve aquatic conditions. The Siuslaw Watershed Council has been organized to facilitate recovery efforts throughout the Basin.
The conclusion of our team is that, while all the present efforts to help the Siuslaw Basin aquatic system recover are well intended and certainly useful, they could be better focused and coordinated. In particular, there needs to be a clearer link established between overall land use and the aquatic system. The streams need to be seen as fundamental aspects of the entire terrestrial environment, rather than as discreet areas that can be "fixed" without changes to upland land management and valley bottom farming. Our recommendations, described in greater detail later in this report, are as follows:
- The first, fundamental step in helping to recover the aquatic ecosystem to health is to identify and secure the habitat that is presently in best condition, and that has the highest potential for aquatic recovery. We have built on earlier work by identifying concentrations of "ecological capital" that appear to support the aquatic ecosystem at the "catchment" scale. Further analysis will be needed before more specific "anchor habitats" can be positively identified and protected.
- Also important is the identification, nurturing, and building of "social capital" throughout the basin. We define social capital as all the individuals, institutions, and collective knowledge that are playing positive roles in protecting or restoring the aquatic system. We have identified some of these in this report, but feel that this is an area best addressed by the Watershed Council over the long term. In the end, the people who live, work, and own land in the basin will be the ones to restore it to health, or restoration simply will not happen.
- Restoration and protection should be matched to the varying geography of the basin. Those streams nearest the coast are closely tied to the estuary and condition of the low lying valleys. Wetland and riparian restoration activities may have very high value here. In the Coast Range mountains, the focus should be more on restoring the natural dynamic of the debris flow process. This means stabilizing or removing mid-slope roads, and finding ways to leave significant amounts of trees in high and moderate risk areas. In the upper watershed, riparian and wetland restoration again rise in importance, along with attention to farm and forest best management practices and reductions in road density where possible. Culvert modifications to improve fish passage may also make the most sense in this area.
- The long run goal should be to retain or restore natural processes that are essential to the aquatic ecosystem. But it may in some cases take 50–100 years to achieve this goal. In the meantime, restoration projects should be planned as "temporary bridges" that will improve local habitats until natural process are once again functional. In-stream habitat improvements at this time appear to be most effective in upper watersheds, in relatively confined streams, where flows are most stable, and at natural "flats," where organic and sediment storage is most crucial.
- Additional actions that hold promise include: land acquisitions or trades, particularly in the "checkerboard" area, or where there are key in-holdings on sensitive lands. Riparian thinning and planting aimed at restoring large conifers (though alder conversions must be done with care to avoid loss of precious shade and nutrient input). Fish passage improvements are beneficial, but it should be noted that many of the upper, steep gradient creeks were always somewhat cut off from the lower ones, and that these may in some cases be important refuges for resident trout.
It is the "suite of environmental forces" across the landscape that maintains the aquatic system over time. Large trees sliding down the steep ravines and into streams, then transported to flat areas where jams form and nutrients are held, floodplains that store water and release it slowly, forests that capture rainfall and fog, riparian woodlands that shade streams as well as providing wood and nutrients, and busy beavers re-building wetlands. We need to find ways to work with these and other elemental forces of the land by forming a stronger partnership with nature. Ultimately, this means modifying the way we farm, build homes, and manage forests. Getting basic land use more in synch with natural processes may ultimately be more important than investments in restoration projects.
We must acknowledge that we lack any good models for restoring a 500,000-acre river basin to health. For the past 130 years, we, our parents, and grandparents have altered the habitat of the Siuslaw watershed to a point where the aquatic system is clearly in trouble. This was not done deliberately, but rather out of ignorance of how the system works. We are still fairly ignorant. Thus we should view all of our efforts (including this assessment) with humility. A clear need is to more methodically build in experimentation and a willingness to abandon efforts that are not working in favor of those that have a better chance. This is known as "adaptive" management. It requires a commitment to monitoring, learning, and an openness to try new approaches.
The remainder of this document will focus in more detail on aspects of the aquatic ecosystem and issues. The last chapter outlines a proposal for aquatic conservation and recovery.
Lastly, no one (to our knowledge) has ever restored a 500,000-acre river basin to health. For the past 130 years, we, our parents, and grandparents have altered the habitat of the Siuslaw to a point where the aquatic system is in trouble. This was not done deliberately, but rather out of ignorance of how the system works. We are still fairly ignorant. Thus we must view all of our efforts with humility, need to methodically build in experimentation, and be willing to abandon efforts that are not working in favor of those that have a better chance. This is known as "adaptive" management. It requires a commitment to continued monitoring and learning.