Natural features

The Calapooia River watershed has many natural features that favor fish and wildlife. The fractured basalt in the upper portions of the watershed yield cool water, ample flow, and deep bedrock pools that provide critical summer holding areas for adult chinook salmon. These same features also create important rearing areas for other native fishes such as cutthroat trout, mountain whitefish, and steelhead. Because the main Calapooia River is naturally warm even 60 miles from its confluence with the Willamette River, fish move into these cool headwater tributaries during the summer.

The valley broadens in a downstream direction and the river upstream of about where the Sodom Ditch diversion now exists is rich in gravel substrate. The channel gradient is less here and the river meanders freely, creating features that favor all native fish during non-summer months. The wide river meanders create zones of lower-velocity water and gravel bars for spawning and production of aquatic organisms which are food for fish. During high flows, the river spreads out across a wide floodplain, which also allows the spread out and feast on terrestrial sources of food. The water has unusual clarity because the sediments are derived from basalt rocks and the silt and clay component is readily flushed downstream. The streamside areas consist of well-drained fertile alluvium that grows both hardwood and conifer trees. At one time, log jams derived from streamside trees were abundant along the river and tributaries, further contributing to channel complexity and high quality fish habitat. Cool tributaries with summer water are rare in this portion of the watershed, although Brush Creek offers one such refuge for fish to escape the warm river.

The river and its tributaries change character downstream of where the Sodom Ditch diversion now exists. The channel gradient slackens as the river traverses across the silt-rich Missoula Flood deposits of the Willamette River valley. The slack gradient causes the river to meander often and it readily floods beyond its banks during high flows. Channels that are dry during the summer months fill with water during the winter and immediately become used by fish. The low-lying ground along the river has always supported a dense and diverse hardwood stand of trees that contributes large wood and leaf litter to the channel. These inputs support a productive environment for fish, birds, and western pond turtles. Except during the summer months when cool-water fishes need to move upstream to avoid the high water temperatures, the fish and wildlife are able to find much to eat. Also, because the river spreads out during high flows, the water velocity is low and the fish do not need to expend much energy fighting downstream displacement. The river meanders sharply and creates oxbow lakes, much to the benefit of turtles, water fowl, and other native wildlife. Depressions scattered throughout this ill-drained landscape were seasonal wetlands heavily used by water fowl. Annual burning by the Native Americans once created expansive areas of grass adjacent to the corridors of riverine hardwoods and promoted successful nesting by pond turtles. The turtle nests need to be exposed to full sunlight in the spring for the eggs to develop. Whitetail deer, now gone from the area, fed on the grassy plains by the thousands.

Alterations to the watershed

European settlement in the Calapooia River watershed initiated changes in some of the natural processes that made this area so productive for fish and wildlife. Probably, of most important to migrating fish, was the construction of dams and other barriers to fish. Of those barriers that persist, the most significant are the dams on the Calapooia River and Sodom Ditch near the Thompson Mills site and the Brownsville Dam site upstream of Brownsville. Both sites greatly influence the ability of spring chinook salmon spawners to access cool holding pools in the upper watershed during early summer. The dams also impede movement of juvenile salmon and steelhead, as well as cutthroat trout and mountain whitefish, as they attempt to move upstream into cooler water during the summer. Some culverts on the tributaries, many of which pass streams under county roads, impede fish movement. In a few cases, small irrigation diversion dams keep fish from using high quality reaches of stream.

Those chinook salmon spawners that reach their traditional summer holding pools in the upper reaches of the watershed are faced with an additional challenge. Many of these deep pools are used by people for swimming on hot days. This displaces the fish and forces them into the few remaining pools not used by swimmers. Crowding spawning salmon makes them more vulnerable to passing diseases among each other. An additional threat to the adult chinook salmon is poaching. The clear water and lack of logs in the deep pools make them easily detected.

The removal of trees along the edges of the river and its tributaries, especially along middle and upper portions of the watershed, over the last century has left a streamside forest that is young and dominated by many hardwoods. Without a steady supply of long-lived and large conifers to a stream, the channel can become starved of the logs that would normally create the pools and high water refuges so critical to fish. Intentional removal of logs from channels over the decades has also contributed to this lack of wood. While a common activity elsewhere in the Pacific Northwest, only a few streams in the Calapooia watershed have been rehabilitated by adding logs back to the channel. Most of this restoration work has been done on land managed by Weyerhaeuser Company in the upper watershed.

Water temperatures recently measured throughout the watershed are probably similar to natural patterns except along some tributaries. The main channel of the river is wide throughout much of its length and even if mature conifers and hardwoods again grew along the banks, the trees would still not provide much shade to the summer channel. Rapid regrowth of trees along those forest streams once bared of trees, combined with current regulations for retaining wide buffers of trees during future timber harvest, means that shading levels are high on forest land. Shade is sparser along streams not subject to the Forest Practices Rules and is most critical where there is the potential of the stream providing cool water refuge for fish during the summer. Brush Creek is an example of a year-round stream that is suitable, to some extent, for supporting steelhead and trout during the summer but could be made cooler and more productive if streamside vegetation was restored along selected reaches that are currently grazed by cattle and horses.

The state has granted many water rights to landowners along the Calapooia River and its tributaries. The amount of permitted water use far exceeds the natural flow of the river. Nevertheless, the existence of a large and old (non-consumptive) water right at the Thompson Mills site in the lower watershed, in combination with an agricultural industry currently devoted to growing grass seed, has meant that the river flow is not greatly influenced by the water rights. Water use is most critical on small streams such as Oak Creek that has low natural flows in the summer. Those headwater streams that provide most of the cool water habitat in the summer have very little water use.

Soil erosion within the watershed is probably higher than it was historically, although erosion levels are naturally high due to steep headwater terrain and entrainment of the Missoula Flood deposits as the river meanders widely downstream of the Sodom Ditch diversion. A flood in 1996 washed out a number of roads in the upper watershed and lead to a concerted effort to upgrade sections of roads to make them less vulnerable during future floods. The extensive grass seed fields in the middle and lower portion of the watershed exhibit some accelerated erosion, especially since field burning has been replaced by periodic tilling to deal with chaff, weeds, and diseases. Nevertheless, the degree of soil erosion does not seem to influence overall water characteristics of the lower watershed much. Most accelerated erosion in grass seed fields originates from the practice of tilling through and filling of intermittent channels during planting, followed by removal of this material by water during the winter high flows.

Grass seed farming has influenced lower-watershed tributaries the most due to the practice of excavating the streams to promote water drainage and straight-line tilling. Much of the length of Oak Creek and upper Courtney Creek consists of trapezoid-shaped channels that were excavated within the grass seed fields. These stream channels also commonly lack streamside vegetation. Overall, they provide little high-quality fish habitat.

A major source of sediment transport in the Calapooia River is a result of channel meandering in the middle and lower portions of the watershed. This is a natural process that has little consequence in the lower watershed since little human infrastructure exists in active areas. And the fish have evolved with this level of sedimentation. However, conflicts between river meandering and landowners sometimes occurs in the middle section of the watershed. Landowners with farm fields, houses, or barns at the edge of the river occasionally request financial support from federal agencies to construct riprap or other devices to keep the river from meandering at certain locations. So far, this has been done at only a few sites along the Calapooia River. Nevertheless, the consequences of extensive meander controls on a river can be observed elsewhere in the Willamette basin. Where rivers have been treated in such a way, conflicts among landowners and declines in fish habitat invariably occur. Stopping the meandering on one segment of river usually causes an upstream or downstream increase in meandering, often creating problems for neighboring landowners. By decreasing the meandering of a river, water velocity increases, the river bottom downcuts, gravel bars become coarser, and zones of still water decrease; all of which are detrimental to fish. Treating a bank to control meandering cannot be justified on the grounds of decreasing overall river sediment loads since the control measures cause corresponding shifts in river meandering upstream and downstream of the site.

Farming and grazing in the Calapooia River has not led to elevated levels of nutrients in the water during the summer and fall; the time of year when added nutrients can lead to nuisance levels of algae and murky water. Nitrogen is added to grass seed fields in the spring and some leaching of that nitrogen does occur when it rains. But by summer, little nitrogen is in the water column. More importantly, phosphorus available for the algae to use is scarce throughout the watershed. There are no discrete sources of phosphorus created by human activities, such as effluent from sewage treatment plants or from confined animal feed lots.

One human-created water quality problem is fecal bacteria. Basin-wide monitoring suggests that water is relatively free of bacteria from human or animal sources in most of the watershed. However, a discrete source or sources exist in Oak Creek; especially within that portion of the stream flowing through Albany. Bacteria concentrations in Oak Creek exceed state water quality standards and even influence the Calapooia River at it confluence with the Willamette River. The park at the confluence is a favorite swimming area.

Pond turtle habitat and their populations have been especially altered by human changes in the watershed. Decades ago, largemouth bass were introduced to the Willamette River and have since been a constant threat to the survival of young turtles. More importantly, pond turtles no long have much habitat that allows for successful nesting. Blackberry vines and other introduced weeds quickly invade bare or natural grass areas and block the sunlight needed warming the soil and fostering egg development. Farm fields can provide open space but tilling can dice up the eggs or collapse the shallow burrows. An increase in turtle egg predators (more coyotes, raccoons, and dogs) due to a lack of top predators, combined with the other above-mentioned factors, has lead to dismal turtle reproduction rates in the Willamette valley.

Restoration and protection opportunities

Since it has no regulatory authority, the Calapooia Watershed Council has limited ability to control land use and the treatment of streams in the watershed. Nevertheless, the power of persuasion and information coupled with outside funding sources can lead to significant gains in restoring degraded habitat and protect existing high-quality habitat. The challenge is usually one of where to start.

Overall, the Calapooia River watershed is in good shape. Many natural features that historically promoted high fish and wildlife productivity are still intact. Many of the processes that have been altered by humans over the years are reversible. Its current environmental health can be best described as a string of pearls (high quality habitat) with a few of the links between adjacent pearls missing.

In this section, we provide a summary of specific restoration and protection activities suitable for a watershed council to tackle and address the most important missing links. The issues are listed in order of importance.

1. Improve movement of fish into zones of cool water during the summer.

Continue to work for a solution on the passage of adult chinook salmon over the dams associated with the Thompson Mills site.

Continue to work with the Corps of Engineers on an alternative solution for fish passage at the Brownsville Dam.

Replace or modify selected culverts that hinder fish movement in cool tributary streams (especially Brush Creek).

d. Modify irrigation water diversion dam near mouth of West Fork Brush Creek to allow fish passage.

e. Improve chinook holding pools in upper Calapooia River to discourage swimming and hide adult fish from poachers.

Identify deep pools in the upper Calapooia River where water temperature is below 70 degrees (upstream of Hands Creek) and add multiple large logs with rootwads. Engineer for stability during flood flows.

b. Eliminate parking areas along main line road near improved pools.

c. Add large wood to selected tributaries in order to improve channel conditions for fish, especially in cool tributaries.

Select cool streams with gradient less than 4 % to add large wood jams capable of creating habitat features that offer fish refuge during high flows, deep pools, and smaller-sized gravel beds (Brush Creek is a good example).

b. Focus first on streams with year-round flow.

c. Increase shade along selected streams to expand cool water zones.

Use fencing, weed control, and plantings to increase shade along stream sections that have maximum temperatures close to 70 degrees, for purposes of expanding the zone of cool water (such as Brush Creek).

Work from a downstream to upstream direction, eliminating even small breaks in shading.

Increase the number of conifers along the Calapooia River to improve large wood for the channel and wildlife habitat.

Use fencing, weed control, and planting of native conifers in appropriate sites.

b. Focus most of the efforts on the middle Calapooia River area.

c. Improve pond turtle reproduction and habitat in downstream portions of the watershed.

d. Improve nesting habitat along the lower Calapooia River by removing exotic vegetation near ponds along the river and converting to low native grasses.

e. Add tethered floating logs to ponds to increase basking opportunities and protect turtles from predators.

f. Encourage landowners along selected tributaries to lease their water rights to the state for purposes of having more water in the stream during the summer for fish.

g. Focus on cooler streams with higher quality habitat (such as Brush Creek).

Consider setting up a flow monitoring program to make sure that flow from leased water rights is not being used by holders of junior water rights.

Provide outreach and education on the importance of channel meandering for providing complex habitat in the Calapooia River. Work with landowners to avoid bank control efforts.

a. Focus efforts on the middle Calapooia River area.

b. Encourage farmers to convert non-functioning wetlands on marginally productive land for use as a wetland bank that could create revenue and wildlife habitat.

Best suited for former wetland areas located near streams.

Work with the City of Albany and others to monitor bacteria in streams and identify source areas.

Focus on areas, such as Oak Creek where there are identified bacteria issues.

Work with the City and landowners to eliminate identified bacteria sources.