Biodiversity Guide - The Intertwine

egional conservation strategybiodiversity guideAppendix I WatershedsFIGURE I-1WatershedsKSt. HelensHRidgefieldLaCenterFI. WatershedsappendixIScappooseBattleGroundJBanksVancouverLForestGroveCorneliusThe extent ofthe Intertwineregion was definedto encompass thePortland-Vancouvermetropolitan area and itssurrounding landscapesand watersheds. It connectswith, but largely excludes,the main Cascade and CoastalRanges and the heart of theWillamette Valley; these areas arewell represented by previousprioritization efforts. This mapdepicts the watersheds reported on inthe RCS report, which include HUCsub-basins, partial sub-basins, andNewbergBHillsboroWoodburnBeavertonTigardTualatinSherwoodWilsonvillewatersheds. The region includes eight HUC-4 sub-basins; in thecase of two—the Lower Willamette and the Middle Willamette—wechose to report on the watershed (HUC-5) level.RCS Defined WatershedsHUC 5 watersheds are lightly outlined * Represents a partial sub basinA - Abern ethy C reek-Willamette River Watershed (87,000 ac)B - Ch ehalem Creek-Willamette River Watershed (78,000 ac)C- Clackamas Su b Basin * (158,500 ac)D - Hayden Island-Co lu mbia River Watershed (18,500 ac)E - John so n Creek Watershed (60,000 ac)F - Lewis Su b Basin* (221,000ac)LakeOswegoAMilwaukieCanbyPortlandMIEOregonCityMolallaDHappyValleyCamasTroutdaleGreshamDamascusWashougalCEstacadaGSandyG - Low er Colum bia-Sand y Sub Basin* (217,500ac)H - L ower Columbia-Slatskan ie Sub Basin* (22,000ac)I - Molalla-Pu dding Sub Basin* (181.000ac)J - Salmon Creek-Fro ntal Columbia River Watershed (131,500ac)K - Scappoo se Creek-Fro ntal Columbia River Watershed (181,000ac)L - Tualatin Sub Basin (453,500ac)M - Willamette River-Fro ntal Columbia River Watershed (78,000ac)Conservation biology is scale dependent. Asone zooms in from the scale of the entireEarth down to continents, countries, and statesand further down to neighborhoods and evenbackyards, the ecological role, function, andimportance of the geography being viewedkeep changing. What is critically important atone scale may not be at larger or smaller scales.Providing an understanding of the importance,ecology, and connection to watershed and landscapehealth at multiple scales was an importantmotivation in developing the Regional ConservationStrategy and Biodiversity Guide. This chapterpresents the view at the scale of the individualwatershed (USGS HUC 4 and HUC 5; see Chapter1). Some issues are common among many orall watersheds; however, given the geographic andsocio-economic diversity within the region, eachwatershed also has unique elements and challenges.The short descriptions of watersheds in thischapter are introductions that lead to otherresources that have been developed by local, state,and federal organizations and agencies (especiallywatershed councils in Oregon). Where awatershed crosses the boundary of the greaterPortland-Vancouver region (as defined in thisBiogeography Guide and the Regional ConservationStrategy) we try to distinguish betweenissues relevant in the entire watershed and thoserelevant to the area within the greater Portland-Vancouver region. Table I-1 lists the watershedsin the region.1. Clackamas River SubbasinCheryl McGinnis, Clackamas River Basin Council,and Carol Murdock, Clackamas County WaterEnvironment ServicesIncludes these named USGS HUC watersheds:Eagle CreekLower Clackamas RiverLower Clackamas RiverThe Clackamas River subbasin is located inClackamas and Marion counties, Oregon, eastand south of the Portland metropolitan area. TheClackamas River is a tributary of the WillametteRiver that enters the Willamette at approximatelyRiver Mile (RM) 25, the last major tributarystream downstream of Willamette Falls. Elevationsin the watershed range from approximately234235