1. ABSTRACT The upper Willamette basin from Eugene to Albany was settled by Euro-Americans in the 1840’s. Since then, the Willamette River had been a vital part of the economy and way of life. The river was historically the fastest and safest way to transport goods and people. Over time, this river section has been altered from multiple channels to a simplified and often single channel system. Settlers simplified channels by construing ‘closing dams’ or ‘cut off dams’, drained wetlands, diverted secondary channels and revetments. With a simpler channel, the river travels at a greater speed, inducing bank erosion and channel bed degradation. Additional alteration of channel hydraulics resulted in greater floodplain recurrence intervals in the mid-valley, and provided a measure of flood control. Even though similar processes may occur naturally, they span a greater time frame compared to the effects of human alteration. River restoration in the upper basin is currently underway. Local dam removal and wetland enhancements are helping to bring the river back into harmony. INTRODUCTION This poster will show the changes made to the Willamette River by the first Euro-American settlers. How they changed the river to suit their needs, the benefits and consequences of their actions on the river and surrounding area. Also, how the community now is trying to restore the river to its once grander state. BENNIFITS OF RIVER SIMPLIFICATION Figure 1 shows the area the upper Willamette river once took in 1854. The main reason why they simplified the river was for commercial and ferry boat traffic. The most troublesome area were the curves at Corvallis. The “light-drought Steamers” were the most common boat used at the time as seen in figure 4. Downed trees and woody piles contributed to the meandering and multiple river channels. HOW THE RIVER WAS CHANGED l Cut off Dams in figure 3 were built across the entrance of sloughs. Wood pilings and rocks were used to cut off the water flow into the sloughs and wetlands. A deeper channel was a direct result. After the water was drained, level fertile soil was exposed for farming. Many of the cut off dams can still be seen. The dam in figure 3 is just north of Salem. l Increased channel depth therefore increased the width of the channel. On average the widths went from 280 feet in 1852 to 440 feet in 1990 CONCLUSIONS We will never be able to get the River back to its pre-settlers path or conditions. They did what they needed to so they could survive in their new surroundings. The Upper Willamette River is an ecologically altered system. Historic flooding has been decreased by 90%. Areas that used to flood every 10 years now are 100 year flood plains. Simplification made boat traffic safer and faster. Draining of the sloughs and wetlands has increased the agricultural benefits of the region. References Cited Benner, P.A. and Sedell, J.R., 1997, Upper Willamette River landscape; a historical perspective, in River quality: dynamics and restoration, Laene, A. and Dunnette, D.A.,eds.,p. 23-47, CRC Press, Boca Raton, Florida. Lyons, J.K., and Beschta, R.L., 1983, Land use, floods and channel changes: Upper Middle Fork Willamette River, Oregon (1936-1980): Water Resources Research, v.19 no.2, p. 463-471. Land-Use History and Hydrologic Alteration in the Upper Willamette Basin Prepared by: Heather Hintz Western Oregon University, Spring 2008 You can insert images throughout poster Figure 3. Cut-off Dam construction Figure 5. Stream Bank stabilizing rock between Eugene and Albany Fig.1 Willamette River simplification over 14 miles Figure 4. Paddle boats were a common transportation up and down river Figure 2. River Simplification IN-CHANNEL PROBLEMS Large woody debris called ‘snags’ and ‘drift piles’ made boat traffic hard in times of low water. A common feature in the river channel, snags added cover for fish and slack points, in turn trapping sediment, debris and other nutrients. US Army Corps of Engineers removed 69,000 snags and overhanging trees from 1870 to 1950. CULTURAL PERSPECTIVE The communities living on the rivers edge are trying to keep the river from moving. Stream bank revetments are being added at the cut banks side of the river. Figure 5 is a map showing where the major stabilization projects have occurred. Everyone likes living next to the river, but no one likes it when the river flood and cuts the bank back. New houses along the river cut away the bank vegetation so they have a better view of the river. Revetments are made up of large rock and wood pilings. The construction of the revetments have made habitats waterfowl and the Western pond turtle. These will not solve the problem for the next generation. The river will always find a new channel.