APPENDIX I Watersheds APPENDIX I: WATERSHEDS CONTENTS Watersheds Index..........................................................................................233 Watersheds ....................................................................................................235 1. Clackamas River Subbasin ................................................................235 2. Lewis River Subbasin .........................................................................240 3. Lower Columbia – Clatskanie Subbasin .........................................246 3a. Cathlamet Channel - Columbia River ............................................247 3b. Kalama River - Frontal Columbia River .........................................251 4. Lower Columbia – Sandy Subbasin .................................................255 4a. Sandy River .........................................................................................255 4b. Washougal River ...............................................................................261 4c. The City of Washougal – Columbia River ....................................265 Overview of the Willamette River Watershed ...................................269 5. Johnson Creek Watershed .................................................................272 6. Salmon Creek – Frontal Columbia River .......................................276 7. Scappoose Creek – Frontal Columbia River Watershed .....................................................280 8. Willamette River – Frontal Columbia River Subbasin and Hayden Island-Columbia River Watershed .................................................................................................284 9. Abernethy Creek–Willamette River Watershed (Greater Oregon City) ............................................................................290 10. Chehalem Creek–Willamette River Watershed ..........................294 11. Molalla-Pudding Subbasin .............................................................297 12. Tualatin Subbasin .............................................................................303 233 REGIONAL CONSERVATION STRATEGY BIODIVERSITY GUIDE APPENDIX I Watersheds FIGURE I-1 Watersheds I. Watersheds H APPENDIX St. Helens LaCenter F I K Ridgefield Battle Scappoose Ground J Vancouver Banks Camas Washougal Portland D Forest L Grove Hillsboro G Cornelius M Troutdale Gresham Beaverton Happy Milwaukie Valley onservation biology is scale dependent. As Portland-Vancouver region (as defined in this Damascus Tigard Lake one zooms in from the scale of the entire Biogeography Guide and the Regional Conser- The extent of Oswego C the Intertwine E Sandy Earth down to continents, countries, and states vation Strategy) we try to distinguish between region was defined Tualatin Sherwood to encompass the Oregon and further down to neighborhoods and even issues relevant in the entire watershed and those City Portland-Vancouver backyards, the ecological role, function, and relevant to the area within the greater Portland- metropolitan area and its Newberg Wilsonville importance of the geography being viewed Vancouver region. Table I-1 lists the watersheds surrounding landscapes C Estacada and watersheds. It connects A keep changing. What is critically important at in the region. with, but largely excludes, B Canby one scale may not be at larger or smaller scales. the main Cascade and Coastal Ranges and the heart of the Providing an understanding of the importance, 1. Clackamas River Subbasin Willamette Valley; these areas are ecology, and connection to watershed and land- well represented by previous Cheryl McGinnis, Clackamas River Basin Council, scape health at multiple scales was an important prioritization efforts. This map Woodburn Molalla and Carol Murdock, Clackamas County Water depicts the watersheds reported on in I motivation in developing the Regional Conserva- the RCS report, which include HUC Environment Services tion Strategy and Biodiversity Guide. This chapter sub-basins, partial sub-basins, and watersheds. The region includes eight HUC-4 sub-basins; in the presents the view at the scale of the individual Includes these named USGS HUC watersheds: case of two—the Lower Willamette and the Middle Willamette—we watershed (USGS HUC 4 and HUC 5; see Chap- chose to report on the watershed (HUC-5) level. Eagle Creek ter 1). Some issues are common among many or Lower Clackamas River all watersheds; however, given the geographic and RCS Defined Watersheds socio-economic diversity within the region, each HUC 5 watersheds are lightly outlined * Represents a partial sub basin G - Lower Columbia-Sandy Sub Basin* (217,500ac) Lower Clackamas River watershed also has unique elements and chal- The Clackamas River subbasin is located in A - Abernethy Creek-Willamette River Watershed (87,000 ac) H - Lower Columbia-Slatskanie Sub Basin* (22,000ac) lenges. Clackamas and Marion counties, Oregon, east B - Chehalem Creek-Willamette River Watershed (78,000 ac) I - Molalla-Pudding Sub Basin* (181.000ac) The short descriptions of watersheds in this and south of the Portland metropolitan area. The C- Clackamas Sub Basin * (158,500 ac) J - Salmon Creek-Frontal Columbia River Watershed (131,500ac) chapter are introductions that lead to other Clackamas River is a tributary of the Willamette D - Hayden Island-Columbia River Watershed (18,500 ac) K - Scappoose Creek-Frontal Columbia River Watershed (181,000ac) resources that have been developed by local, state, River that enters the Willamette at approximately E - Johnson Creek Watershed (60,000 ac) L - Tualatin Sub Basin (453,500ac) and federal organizations and agencies (espe- River Mile (RM) 25, the last major tributary cially watershed councils in Oregon). Where a F - Lewis Sub Basin* (221,000ac) M - Willamette River-Frontal Columbia River Watershed (78,000ac) stream downstream of Willamette Falls. Eleva- watershed crosses the boundary of the greater tions in the watershed range from approximately 234 235 REGIONAL CONSERVATION STRATEGY BIODIVERSITY GUIDE APPENDIX I Watersheds TABLE 9-1 Watersheds in the Greater Portland-Vancouver Region, Organized by U.S. Geological Survey Subbasin n Has 4,228 acres within Federal Emergency having relatively flat or rolling topography. A few Subbasin Watersheds Included in the Watershed Acres Management Agency (FEMA) 100-year flood- buttes (such as the Boring lava domes) occur in Greater Portland-Vancouver Region within the Region plains. this area. Clackamas 1. Clackamas Subbasin (partial) 158,300 n Includes about 1,500 acres of mapped Western Cascades Lowlands and Valleys. This area Lewis 2. Lewis Subbasin (partial) 220,800 wetlands. includes most of the mainstem Clackamas River Lower Columbia – Clatskanie 3. Lower Columbia-Clatskanie Subbasin (partial) 22,000 and floodplain upstream of River Mill Dam; the The majority is privately owned, although agen- upper extent of the Deep, Clear, and Eagle creeks; Lower Columbia – Sandy 4. Lower Columbia-Sandy Subbasin (partial) 217,200 cies including the U.S. Bureau of Land Manage- North Fork Eagle Creek; and the lower elevation Lower Willamette 5. Johnson Creek 60,100 ment, U.S. Forest Service, Oregon Parks and portions of the middle and upper Clackamas Recreation Department, and Metro own some 6. Salmon Creek-Frontal Columbia R 131,400 tributaries, i.e., Fish Creek, Roaring River, Oak significant natural areas in the region. Portions of Grove Fork, Collawash River, and Hot Springs 7. Scappoose Creek-Frontal Columbia R 123,100 the cities of Sandy, Gladstone, Oregon City, Es- Fork. The area is characterized by low mountain 8. Willamette R-Frontal Columbia R 78,700 tacada, Happy Valley, and Damascus are located ridges, buttes, valleys, and medium-gradient riv- (includes Hayden Island – Columbia River) (Willamette R-Frontal Columbia) within the Clackamas subbasin. ers and streams. 18,600 A variety of habitat types can be found in the Humans have occupied the Clackamas sub- (Hayden Island – Columbia River) Clackamas subbasin. The U.S. Environmental basin for thousands of years. The original Native Middle Willamette 9. Abernethy Cr-Willamette R 87,100 Protection Agency (EPA) has developed the con- American inhabitants were bands from two major cept of ecoregions. Three Level IV ecoregions are 10. Chehalem Creek-Willamette R 78,200 tribal groups, the Clackamas Chinook and the represented within the portion of the Clackamas Molalla-Pudding 11. Molalla-Pudding Subbasin (partial) 181,000 Northern Molalla. Populations of both tribal subbasin that falls within the greater Portland- groups were decimated in the early 1800s by a Tualatin 12. Tualatin Subbasin 453,200 Vancouver region: prairie terraces, valley foot- series of epidemics thought to have been brought Total 1,829,600 hills, and Western Cascades lowlands and valleys. to the area by fur trappers. The Clackamas Prairie Terraces. This area, which is located along Chinook primarily occupied the lower lying and the Clackamas River downstream of River Mill northern parts of the subbasin, while the North- Dam, consists primarily of the lower Clackamas ern Molalla occupied the higher elevation and 10 feet, at the confluence with the Willamette Clackamas Subbasin (partial) mainstem and lower tributary areas. This area southern parts. 158,279 acres River, to more than 7,200 feet, at Olallie Butte is nearly level, slightly depressional, or includes Historically, the Clackamas Basin was about located along the southeast boundary of the sub- Land cover % of Watershed undulating fluvial terraces with sluggish,