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o W2 0 0 0 0 AcknowLedgments 0 0 0 0 . Th s atlas was made pass be by the cooper io and Metro U.S. Geological Survey support of a our partners. Weg eatly apprec ate ohn regonese, d rector of Growth Management uMark Uhr ch On the front coven A Landsat Thematic Mapper satellite image, reprinted with permission from the Earth Obser- Servces Department the r wil ngness to ook be end tradt ora agency roles ard bound r es o help us co led nformat on Day d Au berman, senor reg oral p arrer University of Washington coverngtbeen rewaer hed. Dave D e chey OS anal at "Deres Booth, Ph D., Ch st ne Fr aysor, assoc ate mauagemert ara yst We are esoec sly gratefu fort e t rae, ded cation Sue Gemme ,graph c design spec al st Techn cal Wor Group (marked below with an *Snsan Pa ne, 015 anayst aster sk'). Th s group spert many hours provid ng eLy n Pu lam associate management aralyst and analyz ng nformation, answerirg quest ens And G S staff from various agencies who prov ded dgit d a Ca by h three of the seven bands (light waves) recorded by a satellite. The combination of bonds allows us to Interpret the type and condition of vegetation based on hue. Visible Band 3, shown in dark blue hues, represents urbanized areas, open water or saturated soil conditions er Sherman, graphic des gn special at sues and review rg the text a d maps to scussing politan region, Mt. Hood and the Columbia River. The image, taken in August 1993, displays C.r1n,, 'en o' regional D .X mr and ass s once provided by the members of the vation Satellite Co., shows the Clackamas River watershed in relation to the Portland metro- Department of Civ I Ergireer ug such as the snowcaps of Mt. Hood (the summit appears pink because of glare). Near-in fra- was, senor pubic ala rs spec a st ensure that the at as s both accurate and useful MarkTurpe ,204t program supervisor red Band 4, shown in orange and brown hues, represents the relative Intensity of plant photo- Our s ucere thanks go to the fo owing ndiv dua National Marine Fisheries Service synthesis (young vegetation with vigorous growth is shown as brighter orange, while slower- who contr buted to th s at as: °M eeDa Environmental Protection Agency Oregon Department of Environmental Quality SI Bogu eqaiph Roge s 'Sob Baumg rtner uy chae Ry ko grart off cer 0 9 9 0 0 9 0 0 9 0 Metro ProjectTeam Rosemary Farfey team nader Susan Payne, map des g and G S growing, mature vegetation is shown by reddish brown hues). Mid-infrared Band 5, shown in green and light blue hues, represents non-vegetated or sparsely vegetated areas such as dry meadows, recently clearcut areas and harvested or dry farmland. The watershed boundary Lynn Putnam, I avon and wrter Christine F n a son, wrter (yellow line) has been added to the image. Oregon Department of Fish and Wildlife Cff chard Sumner Pat Keen Clackamas County ay Ma any npam H den, Department oflransportaton and Development Oregon Trout '°Cart Hahn, Department of Ut t us S eve Hinton 3 aDonna Peterson Boa d o Coun y Comm ss oners 0 . Oregon WaterTrust Off Ce n inS cb.PhD. Clackamas County Soil and Water Conservation District The Wetlands Conservancy *Es her Lev Susan Hudson *Joe Evans Clackamas River Water eGord Ni Ghee Portland General Electric >Do g C amer Human Nature Vaughr Brown U.S. Bureau of Land Management 0 Dwa ne D ppon eRandy Gould (eff N gbbert D ck Pratber U.S. Forest Service °Traci H ckmar Ron Wane Rich Hagestedt S S S S S S SW 0 9662473 S 2 Claukamas Soil and Water Coeseruation D strict 6EPA Ci,,CkC,as Rice, Water Printed on ecycled paper ODEW METRO 997-1025 -GMS Ecic 96443 sg VètIads tOt SE 3 II .I. S I : Figures TabLe of Contents Preface R e mate F gure I. Locator map or the C ackam Fgure 2. C ac arras Rver e evation and e paces Fgure3. Road den ty.............................................................................. F gum 4 Ownersh p n he Clackamas River watershed................ FgureS Acres by and cove type Frgare 6. High p F gare 7. S ape equat on and evamp es ................................................... Fgure 8 Est mated cu ert and uture impervious area................ Fgure 9. Road-stream crossings................................................................ ed ......... ......................... Introduction Stud Area . What a aWateshed. ProjeC Sac grour-d................................................................. .6 ............................................................. e, Concem n the Clac-.amas RveWtershed .I .I S Gaas .......................................................................................... Process.................................................................. roducts............................................................. Technical Considerations Map Scale and Accuracy : . Base Geography F gure I ccxc map Property Ownersh .........................8 Eevation ........................9 Ecoegars .....................0 Geology .................... Tables Taole . Acres a anal sue uroa gra ar bourn ries yea uroan reserves with n the C ackamas Rver watershed text map ...................................................... Table 2. C ac amas River watershed issues nd goa s ......................6 Table 3. H erarcb cal classificat on for the C ackamas sabbus v Stream Status from DBQ 303(d) Des gnat on Process .............................................................................13 ......................7 Table 4. Owner hip n the C ackarra P ann watershed ........................................ TableS. Clean Water ct, Section 303(d) I sted St yams n the C ackamas Rver watershed 1994-96..............2 map Table6. Acres by land cover type .....................21 Table 7. ...................5 : Stream elevator profi es for C ackamas tributar es ...... . .........................7 Topics of Focus: Native Fish and Related Resources of Concern I .......................................... F gure IC. High susceptbil ty to mass w sting ....................................... Data La tatons and Gaps : ant al or surface erosion DesgnatedSpeca Areas Consideracions for Decision-making: Natural Systems ..................8 text Lard ............................................... ............................ St mated percent of imoervious surface by land-use t on ........................................................................................25 Re at ye Surface Erosion Potent a...........................................................................................................................19 ......................22 Rea ye afitra ion I ......................23 20 ......................24 Appendices Considerations for Decision-making: Human Impacts text map Est mated Papa a ion Dens ty........................................................................................................................ 25 .................... 27 mpernious Area I 25 ...................... 28 25 ...................... 29 Eastng Land 26 ...................... 30 future Land Use Plan 26 ...................... 31 AppnndiaA: Conceptual Made for Natve Fsh Appendia B: [St 0 Data Sources Appendia C: References S Sample Analysis Maps text map Areas o P armed Increase in Land-Use ntensity........................................................................................ 32 ...................... 35 Road Stream Cross ngs and Known Imped meets to F sh Passage..................................................... 32 ...................... 36 Re at an Sascept b ity to Mass Wasting .............................................................................................................. 33 ...................... 37 Generazed Stream Grad . Glossary .I .. I.I II II II 0 indicates the map page corresponding to the text description 33 .................... 38 inside back cover ClackaisR iver Watershed Project About Metro A Washington Multnomah County County family.That's because Metro is working to ensure that you have Vancouver Clark County 'Maywood Park Forest Grove Cornelius Hillsboro -84 Portia 4 0 Bea erton 1 Yamhill County Milwaukie Tigárd K ng City Durham Tualatin Lak&. I Oswego Johnson Rivergrove Sherwood Happy Valley 2 Glads one West Li nn Oregon City Wilsonville access to nature ................. Fairview ....... Troutdaie Wood Village Gresham \5O 3 . ' Multnomah County Washington County !fyou live, work and play in the metropolitan area, Metro regional services matter to you and your N Clackamas County S clean air and water -84 . the ability to get around the region . safe and stable neighborhoods . a strong regional economy S resources for future generations Metro serves 1.3 million people who live in Clackamas, Multnomah andWashington counties and the LI;) 24 cities in the Portland metropolitan area. Metro provides transportation and land-use planning services and oversees regional garbage disposal and recycling and waste reduction programs. Executive Officer Council Metro manages regional parks and greenspaces and the Metro Washington Park Zoo. It also oversees Mke Burton Presiding Officer operation ofthe Oregon Convention Center, Civic Stadium, the Portland Center for the Performing Arts District 3 and the Expo Center, all managed by the Metropolitan Exposition-Recreation Commission. Jon Kvistad For more information about Metro or to schedule a speaker for a community group, call 79 7- I S I 0 Auditor Deputy Presiding Officer Alexis Dow, CPA District (public affairs) or 79 7- I 540 (council). I Metro's web site: www.metro-region.org Ruth McFarland Metro is governed by an executive officer, elected regionwide, and a seven-member council elected by District 2 districts. Metro also has an auditor who is elected regionwide. Don Morissette District 4 Susan McLain District S Ed Washington District 6 Lisa Naito M ETRO Regional Services District 7 Patricia McCaig Preface S S S S S S This atlas was created through the Clackamas River or computerized, geographic data for the C!ackamas River watershed. This atlas was produced as one Watershed Project, a project to gather information way to share the information collected with resource managers, policy makers, and people living in and about the watershed's natural resources. This infor- interested in the Clackamas River watershed. mation was coIected to hep the Metro Council and other decision-makers when they evaluated areas in During the first year ofthe Clackamas RiverWatershed Project, Metro staffmet frequently with a .S S S S S S S S S S S S S S S S S which to allow future urban growth. The project many agencies had gathered information about the Clackamas, each agency had focused on the lands natural systems, such as geology, slope, land cover and fish distribution. We also gathered data related to human influences in the watershed, such as population density, land use and zoning. Then, with the information gathered, we used a geographic information system (GIS) to design the maps in this atlas. a smaller riverWatersheds ofany size can also simply be called 'watersheds," with parts ofthese watersheds (such as the land draining to a stream) called "subwatersheds." For the purposes ofthis atlas, we call the land draining to the Clackamas River a watershed" and the smaller stream-based drainages that Study Area feed into the riversubwatersheds." Other agencies may use different terms to refer to these areas (see The project study area is the entire land area draining referred to as the Clackamas River watershed. The Because all water in a watershed is connected, activities in one part ofthe watershed often affect other watershed is part ofthe lower portion of the Wil- areas ofthe watershed. For example, human activities such as construction and timber harvesting, if not shows the watershed in After creating maps covering the entire watershed, we began looking in more detail at the smaller lamette River basin. Figure watersheds that make up the Clackamas. We graphed key variables such as road density (miles relation to Oregon and Washington county bound- quality downstream. Disturbances do not need to occur directly along a stream or in the riparian zone to ofroads per square mile of/and) and p/aces where roads and streams intersect (cal/ed road-stream aries. The map on the cover shows the watershed in have an adverse effect. Each piece ofthe landscape - streams, riparian zones and uplands - plays an crossings). We a/so estimated how much /and in each area is currently covered with impervious (paved relation to Mt. Hood, Portland and the Columbia important role in the watershed's overall health. For these reasons, many ecologists and resource manag- River ers advocate making watersheds, rather than jurisdictional boundaries, the geographic unit for natural or hard) surfaces and how much could be covered with impervious surfaces in the future, as development continues. Graphs showing these key variab/es are included in the atlas. I The Clackamas River watershed drains more than Although the at/as does not ana/yze a/I conditions in the C/ackamas River watershed, it provides a 940 square miles, including forested areas in the starting point to identify areas for more detailed data collection and assessment. upper watershed and agricultural areas and densely Figure 1 developed areas in the lower watershed. The areas have been adopted as urban reserves, those areas designated by the Metro Council for future where the river flows into the Willamette River near S growth in the Portland metropolitan region. We p/an to gather detai/ed information about these two Gladstone and Oregon City, southeast of Portland, S subwatersheds so decision-makers will be able to consider natural resources as they analyze possible Throughout the watershed, numerous small streams development patterns for future urban areas. and tributary rivers feed the waters of the S S S S S S S IS S IS S I performed responsibly, and natural events such as floods or fire can cause erosion and degrade water resource study and management. the slopes ofa High Cascade volcano and ending S S page 6 for more information). into the Clackamas River in northwestern Oregon, that feed into the C/ackamas River: Rock Creek and Richardson Creek subwatersheds. Parts of both .S into the Columbia River or as a small as 20 acres draining to a pond. land area draining to a major river such as the Columbia, while a "subbasin" describes the land draining to Clackamas River is nearly 83 miles long, beginning on S S S S S S S with small watersheds nested within larger ones. A watershed can be as large as all the land draining and has continued into I 997. As we enter the next phase ofthe project, we will focus on two sma// watersheds, or subwatersheds, .. S or lake.Watersheds are bounded by topographic features such as ridgetops.Watersheds are hierarchical, Depending on its size, a watershed can be called different names.Basin" is often used to describe the an area that crosses two counties and includes several cities and towns, as well as U.S. Forest Service We first focused on gathering data to characterize the entire watershed, especially data related to A watershed is any area of land from which water drains to a common point, be it a river, pond, stream local, regional, state and federal agencies and groups, it administered and its own issues ofinterest. The challenge was to gather watershed-based data about and Bureau ofLand Management lands. What is a Watershed? began in September 1995 as a partnership of several cover) to define information needs and determine what digital data was already available. Although S S S S S S S S I Metro received grant funding from the U.S. Environmental Protection Agency in I 995 to gather digital, TechnicalWork Group oflocal, state and federal partners (seeAcknowledgements on the inside front S S S S S Introduction Clackamas. For people with access to a GIS, the digital data used in this atlas is available from Metro (send e-mail to drc©metro.dst.or.us or ca/I (503) 797-! 742 for more information or visit the Data Resource Center, 600 NE GrandAve., Port/and, Ore.). Ifyou have questions or comments about the Clackamas River Watershed Project, send e-mail to 2040@metro.dst.or.us or call Metro's Growth Management Services Department at (503) 797-1562. Project Background The Clackamas Riverwatershed was selected for this project because of its potential for future development. In I 994, Metro's Growth Management Services Department began investigating and analyzing urban reserve study areas. These study areas were Locator map for the CLackamas River watershed ands that could be selected as urban reserves through Metro Council decisions about the urban Key Concerns in the Ctackamas River Watershed Urban Growth TabLe 1 When the Clackamas RiverWatershed Project began, the Metro Council was growth boundary. The council desgnates urban NaturaLLy Spawning Anadromous SaLmonids reserves to accommodate future urban growth in the Portland metropolitan region, in compliance with Oregon's land-use laws. By I 994, several parts ofthe Clackamas River water- in the process of selecting urban reserves, areas that would form the long-range The Clackamas River supports several species of anadromous fish, including spring (30 to 50-year) land supply to accommodate growth in the Portland metropoli- and fall chinook salmon, coho salmon, cutthroat trout, and summer and winter tan region. Urban reserves are outside the urban growth boundary (UGB), steelhead. However fish populations have been declining due to several factors, which designates a 20-year land supply. The number ofacres within the UGB i nd ud i ng: and urban reserves provides some measure ofthe growth projected to occur in Urban growth boundaries shed had been proposed as urban reserve study areas. Metro staff felt that it was important to study Overfishing: Harvest rates on late-run coho salmon have been as high as 80 percent the Clackamas River watershed further because: in recent years. The resulting 20 percent escapement rate is far below the Oregon Department of Fish and Wildlife's estimate of a 3 I percent escapement level needed S The Metro Council and Clackamas County to sustain the harvest ofwild, late-run coho salmon. Board ofCommissioners needed more information about the watershed to make urban reserve decisions and to understand the impacts ofgrowth on the watershed's Acres of Land inside urban growth boundaries and urban reserves, within the CLackamas River watershed Oceanic and downriver conditions: Conditions in the Pacific Ocean and Willamette River that affect fish include limited food, predation, poor water quality, loss or degradation of habitat, and disease. an area. Inside Metro UGB 847 Three governing authorities in the Clackamas River watershed can establish Gladstone UGBs and urban reserves: Metro and the incorporated cities of Sandy and HappyValley 42 Estacada. Metro works with 24 cities and three counties to establish the UGB Oregon City 777 and urban reserves for the Portland metropolitan area. As shown in Table I , the Metro Council has adopted 4,468.2 acres ofurban reserves in the watershed. Urban Clackamas County Total 3436 5102 Sandy also has 2,348.4 acres of urban reserve lands in the watershed. Estacada 697 Estacada has a UGB, but no urban reserves. natural resources. I The watershed supports naturally spawning and organic matter in a rivec Upstream fish passage on the Clackamas River was and coho salmon, and cutthroat trout. Some blocked at Faraday Dam (east of Estacada) from I 9 I 7 to I 939; during this time, no ofthese species could be listed by the federal anadromous fish could reach spawning and rearing areas above the dam (U.S. Forest government as threatened or endangered. If Service Environmental Assessment and Management Plan for the Clackamas Wild a fish were listed, any proposed activities that and Scenic River). Land use (agricultural, timber harvesting and urban uses): Land-use practices such scrutinized. as removing large woody debris from stream channels, clearcutting, removing streamS The Clackamas River provides a valuable side vegetation, withdrawing water for irrigation, mining for gravel in-stream and road source of drinking water for approximately building can increase sediment loads and water temperatures. I 75,000 people and is targeted in the Regional Water Supply Plan as a source to meet future water demand. Metro is a member of When fish populations decline,they may be listed as threatened" orendangered" underthe Endangered SpeciesAct (ESA). The National Marine Fisheries Service ( NMFS) is the federal agency responsible for managing marine species under this act. the Regional Water Supply Planning Study along with 27 ofthe region's water providers. habitat for many wildlife species, both game and nongame animals, and supports numerous recreational activities such as fishing, boating and camping. Metro worked with The Wetlands Conservancy, Clackamas County and the Oregon Graduate Institute's StudentWatershed Research Project to chinook salmon, cufthroat trout and the Lower Columbia River/Southwest Washington Coast coho salmon ESUs are possible candidates for listing. Once a species is listed, activities that might affect the fish or their habitat are restricted, as outlined in the Endangered Species Act. 178 1875 Urban reserves In October I 996, water providers in the Portland metropolitan region issued Metro* 4468 the final report ofthe Regional Water Supply Plan. This plan resulted from a Sandy 2348 multi-year study to examine strategies and implement actions to meet the Estacada water supply needs ofthe Portland metropolitan area into the year 2050 Total The Clackamas River currently provides municipal water to about I 75,000 * Acres will be allocated to individualjurisdictions as they are brought into the LJGB. residents in the Portland metropolitan region. Water providers drawing from the Clackamas, including the city of Lake Oswego, Clackamas RiverWater and the South ForkWater Board, have developed intake and treatment capacity for 66 million gallons per day (mgd) on the lower five miles ofthe river Estacada also has an intake. Several new or expanded water supply facilities, providing a total of 22.5 mgd, are currently planned on the Clackamas River within the next As ofthis printing, the Lower Columbia River steelhead evolutionarily significant unit however NMFS has delayed a final decision on the listing. Also as ofthis printing, I Water SuppLy 10 years. ( ESU), which includes the Clackamas River stock, has been proposed as threatened; The watershed is also important because it provides Total stream migration, blocking upstream migration and affecting the storage of sediment anadromous fish including steelhead, chinook might harm the species would be closely Sandy Dams: Hydroelectric development can affect fish by causing mortality during down- The water supply plan recognizes that additional future withdrawals raise concerns about the river's fisheries, but found that withdrawing another 50 mgd should not have severe adverse environmental impacts. The plan adds that the health offisheries and ecosystems needs to be monitored and values preserved as more water is withdrawn. In addition, the plan recommends further study to better understand the possible impacts offuture withdrawals. NA 6816 I S develop a comprehensive proposa to gather infor- Metro: collect and map technical data for the mation about the Clackamas River watershed. The Clackamas River watershed. S proposal was submitted to the Environmental Pro- produce maps ofthe watershed and deter- Although the work group wanted to begin gathering Small work groups developed conceptual models for mine a cost-effective way to make the maps data immediately, members also realized that they each ofthe four issues. Although we did not collect and data accessible to the public should wait until they had determined what informa- data for models showing water quality, water supply tion was needed and how it would be used. An and natural areas, some ofthe data obtained for the overwhelming amount of data is available; without native fish model (see Appendix A on page 39) does specific objectives, data collection could go on indefi- apply to one or more ofthe other models. The nitely. The EPA grant officer strongly advised that the conceptual model can be used as a starting point for group wait to acquire data until after pertinent groups undertaking similar projects in other water- questions about the watershed were formulated. sheds. TheWetlands Conservancy: survey existing methods tection Agency's (EPA) Willamette Basin Initiative. . of rapid assessment and identify one to use in seThe Cl ackamas River Watershed Project received identify data deficiencies and make recom- mendations for addressing them. lected areas. funding from the EPA in September I 995. The three StudentWatershed Research Project: monitor project sponsors (Metro,TheWetlands Conservancy water quality in selected areas. Process and the StudentWatershed Research Project) submitted a joint proposal for the following tasks: ATechnical Work Group of resource managers from Metro/The Wetlands Conservancy/Clackamas federal, state and local agencies was formed as an ad Goals hoc group to review the Clackamas River Water- County: form aTechnical Work Group of project The project was designed to: shed Project's work plan and provide guidance at cooperators to assess data needs for the watershed The challenge was to select a process to assist the Technical Work Group in identifying the data needed Products to answer key questions. The group decided to use conceptual models, which allow us to break an issue Information about the Clackamas River watershed is into its different components and organize informa- available in several formats, including reports, maps tion related to a particulartopic. Forthis project, the and digital (computerized) data. Because Metro staff group identified four issues of concern in the water- have considerable expertise with geographic infor- shed, which they later wrote into goal statements mation systems, the work group and Metro decided and prioritized (seeTable 2). Then, attributes that to focus on acquiring digital data. Data were ana- support each goal were identified. Stressors, or lyzed and maps generated using Arc/Info, a GIS activities that can degrade the attributes, were also developed by the Environmental Systems Research TabLe 2 identified. Finally, characteristics describing each Institute in California. Clackamas River watershed issues and goals* attribute and stressor called indicators, were listed. and help Metro with its data collection efforts. The develop a list of issues and goals related to Technical Work Group was comprised of those natural resources in the watershed key junctures. During the first year the full work group met three times and smaller groups met several times. individuals listed on the Acknowledgments page. S identify' data sources and obtain the data When acquiring data, we looked primarily for existing The group developed a conceptual model for Issue Issue GoaL Native The Clackamas River watershed has several native runs of anadromous fish fish whose numbers are low and/or declining. Priority I . I, data sets rather than generating new ones. We native fish, listing the attributes, stressors and indica- tapped a variety of sources (see Appendix B on page Maintain and improve native anadromous and resident fish tors for fish habitat. Next the group identified more 40), combining the data as necessary to give a corn- habitat in the Clackamas River watershed. than 30 measures, or data sets, on which to focus plete picture ofthe Clackamas River watershed. data-gathering efforts. Examples of supporting With much ofthe watershed in national forest, the attributes for native fish include sufficient water U.S. Forest Service was able to provide extensive quantity and quality, while examples of stressors that digital geographic data for its managed lands. The could degrade fish habitat are lack of riparian vegeta- Bureau of Land Management also provided data tion, barriers to fish passage and road-stream crossings. covering its smaller land holdings. State agencies, Water Significant portions ofthe Clackamas River and its tributaries currently do not Maintain and enhance water quality ofthe Clackamas River quality meet state water-quality standards for temperature. Future land-use changes, watershed to meet and surpass state water-quality standards. growth and development threaten to further degrade water quality. including the Oregon Department of Fish and Maintain sufficient flows to support instream beneficial uses. Water Increased water withdrawals due to increasing regional water supply demands supply may conflict with other beneficial uses. Natural Future land-use changes and growth negatively impact natural areas associated Protect and enhance natural areas associated with river and areas with river and stream habitat. stream habitat. Wildlife and the State Service Center for GIS, have also supplied data. II II II S S *as developed by the Technical Work Group TechnicaL Considerations Map Scale and Accuracy The concept of map resolution is similar to that of a Data collected forthis atlas came from a variety microscope in a scientific laboratory. With the naked of sources, were created for different purposes eye, it is difficult to see tiny organisms in any great and have varying resolutions (see Appendix B for a detail. We may know the general shape and size of complete list ofdata sources and scales). It is essen- a cell, but cannot determine much about its internal tial to consider resolution when using these maps composition. With a microscope, however we are and to avoid using the maps to compare information This atlas represents much, but not all, available AI maps are pHnted wth a specific scae. For example, a I :24,000 map scae means that one nch on the map corresponds to 24,000 nches, or 2,000 important to understand how the data can best be used, given certain data limitations and gaps in generated at a partcular scae, caHed the source scale able to determine detailed information about each from one source with that from another less accu- organism. rate source. For example, the maps should not information. or resolution. Throughout this atlas, a source scale is given for each The same is true for maps ofthe earth. The closer data set. This scale determines the level of accuracy represented in the scale, the less accurate the resolu- information forthe Clackamas River watershed. Before using the atlas to draw conclusions, it is feet, on the ground. Data shown on a map are also for each layer of information. The higher the number Data Limitations and Gaps our view, the greater the detail possible. For example, satellite images are valuable for mapping very be used to determine soil types on either side of a In some instances, the scale at which the data were road because the soils data is only accurate to within generated (the source scale) is too inaccurate for +1- 40 feet, while the road itself may be less than 40 answering specific questions. For example, land cover feet wide. designations were coarsely assigned from satellite large areas, but provide limited accuracy because of imagery over a very large area. This information was tion. For example, a scale of I :500,000 has less detail the great distance from the earth at which they are Note:All maps in the atlas were reviewed for accuracy taken. A closerview provides more accurate infor- by the Technical Work Group. Although we took care in mation. Forthis reason, a road inventory delineated creating the maps, errors, omissions and positional from an aerial photograph will not be as accurate as inaccuracies may occur not thoroughly verified in the field. It is appropriate and accuracy than a scale of I :24,000. The former to display this data for a large area, such as the entire may have been derived from a satellite image and is referred to as small scale" because features in the image appear very small. The latter may have been derived from an aerial photograph and is referred to Clackamas River watershed, to give a general idea of roads measured using surveying equipment on the vegetative cover However,the map would not be accurate enough for classifying the riparian vegetation fragmented ownership and land administration can lead to data inconsistencies and incomplete data. For example, the federal agencies were able to provide road networks with much more detail than available on non-federal lands. This does not neces- sarily indicate that there are more roads on federal land than on private land, but simply that the federal directly next to a stream. have an even larger scale or resolution. Some data are so detailed that a watershed-wide application is too cumbersome. For example, data gathered by walking beside or in a stream - such as stream substrate texture, percent shade, large woody material, and stream width and depth - are important for understanding fish habitat, but would be too detailed to show on one watershed-wide map. . agencies have done a more complete inventory of a a existing roads. 0 Other important information has not yet been a . mapped in GIS format. For example, the Technical Work Group wanted to show the locations of a restoration projects implemented by the U.S. Forest 0 a a Service and Bureau of Land Management on their resource I ands. Unfortunately, these restoration site locations have not yet been mapped and could not be included in the atlas. ground. as large scale." Data gathered on the ground will . Despite these limitations,the data collected for this 0 a a a a a project are extensive and form a foundation that can be expanded overtime. The digital data used in the atlas supplement information about the Clackamas River watershed that is already available in written reports and maps, such as watershed analyses prepared by the U.S. Forest Service and various reports prepared by state and county a a 3 a a a a a e agencies. a The watershed crosses two counties and includes federal land administered by two agencies, state land and private land. These different jurisdictions and Note: The maps are intended to be used with the a . accompanying text which explains the data limitations C specific to each map. C C Built in I 958, the North Fork Dam on the Clockamcis River is operated by Portland General Electric. The dam fish ladder allows adult fish to move upstream into the 33 I -acre North Fork Reservoir and beyond.
