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Home My WebLink AboutWA DNR Mass Wasting Module Appendix A Appendix A Mass Wasting Module Level II Assessment Dave Parks Forest Hydrologist Washington Department of Natural Resources This assessment was performed in accordance with the Standard Methodology for Conducting Watershed Analysis, Chapter 222-22 WAC (Washington Forest Practices Board, 1993), Version 4.0. _______________________ ___________ Qualified Analyst Date c:\watershed analysis\Hoh Mass Wasting\hohmw1.doc Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module APPENDIX A MASS-WASTING ASSESSMENT CONTENTS 1.0 Overview............................................................................................................ 2 2.0 Summary of Geologic and Physiographic Settings Pertinent to Mass-Wasting Interpretations.......................................................................... 4 3.0 Summary of Methods........................................................................................ 7 4.0 Summary of Analysis and Results.................................................................... 8 5.0 Descriptions of Mass-Wasting Units................................................................ 11 6.0 Summary of Critical Questions........................................................................ 17 7.0 Confidence in Work Products.......................................................................... 19 8.0 Appendix A-1..................................................................................................... 20 8.1 References.............................................................................................. 20 8.2 Forms A-1, A-2, A-3.............................................................................. 24 8.3 Maps A-1, A-2....................................................................................... 71 Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 1.0 OVERVIEW The purpose of the assessment is to identify areas within the Middle Hoh WAU that have a moderate or high risk of landsliding due to the effects of proposed forest practices. The Mass Wasting methodology requires that the following Critical Questions be answered by the analysis: What are the potential sediment sources in the basin? Is there evidence of, or potential for mass wasting in the watershed? What mass wasting processes are active? How are mass wasting features distributed throughout the landscape? What physical characteristics are associated with these features? Do landslides deliver sediment to stream channels or other waters? Do forest management activities create or contribute to instability? What areas of the landscape are susceptible to slope instability? What is the relative contribution of sediment from mass wasting compared with other sources? The mass wasting assessment is conducted using aerial photographs, maps and field observations. Using this information, the analyst evaluates mass wasting processes relative to the critical questions. A series of exercises designed to either confidently answer the key questions, or identify more detailed information necessary to do so, is developed in this assessment. The objective of these exercises is to generate information sufficient to establish: 1. The mass wasting features and processes (shallow-rapid landslides, debris flows, and deep-seated failures) active in the basin. 2. Portions of the landscape having similar inherent physical characteristics relative to mass- movement behavior. 3. The relative potential for mass wasting impacts associated with the landscape units. 1.1 INTRODUCTION TO MASS WASTING PROCESSES AND TERMINOLOGY Terminology used to describe mass wasting processes in this assessment follow the classification system established by Varnes (1978) Table 1, which places slope movement into six types (falls, topples, slides, flows, spreads and complex) and subdivides by type of material (bedrock, debris, and earth). Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 2.0 SUMMARY OF GEOLOGIC AND PHYSIOGRAPHIC SETTING PERTINENT TO MASS-WASTING INTERPRETATIONS. The Hoh watershed within the Middle Hoh WAU exhibits a broad glacially carved river valley bordered by steeply sloping valley sidewalls. Un-glaciated hillslopes are composed of colluvial soils overlying predominantly “soft” and structurally deformed marine turbidite sandstones, shales and siltstones. Hillslopes formed in glacial deposits usually occupy positions relatively near the valley floor and are composed of mixtures of till, outwash or lacustrine silt or clay. All hillslopes are occupied by dense vegetation cover and are subject to voluminous annual precipitation mainly in the form of winter rain. These environmental factors, by themselves and when combined with forest management activities, facilitate and promote the initiation of mass wasting events from hillslopes into stream channels. This assessment of mass wasting history and processes in the Hoh watershed is done in the context of the primary environmental variables that affect hillslope stability; topography, geology; hydrology; and vegetation. Topography The Middle Hoh Watershed Administrative Unit (WAU) occupies the middle third of the Hoh River watershed, which drains the west slope of the Olympic Mountains and occupies a land area of approximately 54348 acres. Elevations within the Middle Hoh WAU range from approximately 3000 feet above sea level on the eastern margin to 240 feet at the downstream edge of the Middle Hoh WAU boundary. Geology Hydrology Precipitation within the basin is prodigious. The average annual precipitation at 320 feet above sea level is 167 in./ year.(4242 mm/year) (Amerman and Orsborn 1987) . Most of the annual rainfall occurs between October and May with a pronounced summer dry season. A winter snow pack may develop above 2296 feet (700 m) from December through March (Edmonds and Blew 1997). Precipitation intensity and duration in the Middle Hoh WAU are important factors which contribute to initiation of mass wasting events (Montgomery and Dietrich 1994). Precipitation intensity information in the Hoh watershed is limited by the relatively sparse distribution of rain-gages within the basin. Additionally there are no rain gages equipped to record hourly precipitation, so rainfall intensity data is limited to rainfall amounts averaged over 24 hour periods. Typical 24 hour rainfall intensities in the Middle Hoh WAU range between 5.9 and 6.5 inches for a two year recurrence interval storm (See page C-9, Appendix C: Hydrologic Change Assessment). Historic storms which produced peak flows of greater than a 1.5 year recurrence interval in the Hoh River occurred in 1935, 1955, 1979, 1980, 1982, 1986, 1988, 1990, 1996, 1997 and 1999 (see page C-1, Appendix C: Hydrologic Change Assessment.) Summary of Previous Mass Wasting Investigations Portions of the Middle Hoh WAU have been analyzed for mass wasting processes by a variety of investigators. Fiksdal and Brunengo, 1980, carried out general mass wasting mapping at a very large scale. Swanson and Leinkaemper, 1982, made qualitative observations of the interactions between fluvial processes and mass wasting in Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module the South Fork Hoh River. Kresch and Pierson, 1987, made similar qualitative observations of debris flow hazard in Spruce Creek, a tributary of the main-stem Hoh River. Investigations into the effects of debris flows and other mass wasting processes on; hydrology and channel morphology were carried out by Ryan and Prigge 1991; spawning gravel quality by Hatten, 1991; macroinvertebrate populations by McHenry 1991. Aerial photograph interpretation of mass wasting history of the Huelsdonk Ridge area was completed by Schlicte, 1991. An evaluation of road-related mass wasting hazards and a program for hazard abatement was conducted by Traub, 1991. Quantitative descriptions of mass wasting processes were carried out by Logan et al, 1991, and by Montgomery, 1994, and Montgomery and Dietrich, 1994, for the Huelsdonk Ridge area of the South Fork Hoh sub-watershed. Landslide inventory data from Willoughby Ridge was used in development and calibration of a GIS-based slope stability model developed by Shaw and Johnson, 1995. Deep-seated landslides were mapped and inventoried by Gerstel, 1999 (included in this analysis). Mass wasting assessments conducted in other watersheds on the Olympic Peninsula with similar topography, geology and climate include work completed in the Clearwater River (Reid 1981; Reneau, 1989); North Fork of the Calawah River (O’Connor and Cundy, 1993) (Dieu and Shelmerdine 1997); the Sitkum River and South Fork Calawah River (Lingley 1998) and the Bogachiel River (Ginn 1996; Serdar 1997). 3.0 Summary of Methods This assessment follows the Level II Mass Wasting methodology presented in the Standard Methods for Conducting Watershed Analysis Version 4.0 (WFPB 1995). Prior to conducting the mass wasting assessment, the Middle Hoh WAU was divided into 9 sub-watersheds to provide a framework for organizing the watershed analysis. The nine sub-watersheds were labeled, Alder Creek, Elk Creek, Hell Roaring, Owl Creek, South Fork Hoh River, Spruce Creek, Tower Creek, Willoughby Creek, and Winfield Creek. These sub-watershed divisions were placed on a 1:24,000 scale topographic map of the WAU( Map A-1). Once available geology, soils, hydrology and vegetation information was reviewed for the assessment area, a systematic inspection of available aerial photographs covering the Middle Hoh WAU was undertaken. Aerial photographs taken in 1939 (USGS 1:48,000 Black and White), 1975 (OL-C-75 1:24,000 color), and 1998 (Quillayute/Hoh 1998 1:12,000 color) were viewed with a mirror stereoscope and locations of mass wasting features were recorded on a base-map. Only four sub-watershed areas had complete aerial photograph coverage for all years (Alder, Spruce, Tower and Willoughby). Complete aerial photograph coverage was available for the 1975 and 1998 photo sets. Mass wasting features were then digitized and pertinent attributes of the features were also recorded in data sheets (Form A-1). Deep-seated landslides inventoried by Wendy Gerstel, Geologist, Washington Department of Natural Resources from 1990 aerial photography (Gerstel 1999) were included on Map A-1 and pertinent information recorded on Form A-1. Only limited inspection of these landslides in this assessment was possible due to time constraints. Information recorded for each mass wasting feature included the type of mass wasting process evident and the level of certainty of the observation; the plan form area in acres; whether the mass wasting feature delivered sediment to surface waters and if it did, the specific channel segment (See Channel Assessment Module) that the feature delivered to; associated land use; the apparent hillslope gradient in percent slope; the slope form (convergent, divergent, planar); the underlying rock unit; the elevation of the initiation point; and narrative comments about the mass wasting feature. These observations were recorded in Form A-1 (Appendix A) and organized by sub-watershed unit. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Field inspection of geology and mass wasting features was conducted in September and October of 1999 to verify observations recorded in Form A-1. These inspections were necessary to determine what kind of land use or natural processes were present and likely to influence mass wasting initiation or “triggering”. Once locations of mass wasting features were mapped (Map A-1) and evaluated, land areas with mass wasting features were grouped and divided based on landslide density and mass wasting process into Mass Wasting Map Units (MWMUs) (Map A-2). MWMUs are intended to stratify the land area of the Middle Hoh WAU into areas with High, Medium and Low mass wasting hazards. 4.0 Summary of Analysis and Results In the Middle Hoh WAU, 747 landslides were inventoried over the 60 year period between 1939-1999 (Form A-1 & A-3). 59 % were shallow rapid failures, 31 % were debris flows, 7% were large persistent deep seated failures and 3% were small sporadic deep seated failures (Figure 1). Landslides associated with clear-cuts represent 60% of observed failures. Road-related landslides represent 19% of recorded failures, landings were associated with 3% of observed failures. Landslides associated with mature forests represent 18% of the total population. Two failures were linked with gravel pits and represent less then 1% of the total (Figure 2). Rates of landsliding normalized by area are shown in Table 1. The Alder, Spruce, Tower and Willoughby sub-watersheds were assessed over a period of 60 years, and Elk, Hell Roaring, Owl, South Fork and Willoughby sub-watersheds were assessed over a period of 24 years. In order to generate a meaningful estimate of landslide rates, each sub-watershed landslide rate was calculated individually and a WAU based average landslide rate was determined by taking the mean rate from the population of sub-watershed rates. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 0 100 200 300 400 500 SR LPDS SSDS DBF Landslide Process Middle Hoh WAU Mass Wasting Inventory Failures (n) by Mass Wasting Process Shallow Rapid Large Persistent Deep Seated Small Sporadic Deep Seated Debris Flow Figure 1: Number of landslides observed in the Middle Hoh WAU by mass wasting process. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 0 100 200 300 400 500 Clear Cut Road Landing Mature Forest Pit Land Use Association Middle Hoh WAU Landslides by Land Use Association Figure 2: Number of landslides observed in the Middle Hoh WAU by land use association. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Table 1: Landslide Rates by sub-watershed for the Middle Hoh WAU. Sub-basin Landslides (n) Years Sub-basin Acres Sub-basin Hectares Rate (n/ac/yr) Rate (n/ha/yr) Alder 33 60 3529.87 1428.52 0.00016 0.0004 Spruce 81 60 4168.18 1686.84 0.00032 0.0008 Tower 35 60 3919.22 1586.08 0.00015 0.0004 Willoughby 101 60 4153.25 1680.8 0.00041 0.0010 Elk 122 24 11581.80 4687.10 0.00044 0.0011 Hell Roaring 26 24 3932.90 1591.6 0.00028 0.0007 Owl 165 24 8376.07 3389.75 0.00082 0.0020 South Fork 119 24 6929.73 2804.42 0.00072 0.0018 Winfield 68 24 7756.68 3139.1 0.00037 0.0009 Mean 0.00041 0.0010 5.0 Description of Mass Wasting Units The distribution and area of Mass Wasting Map Units (MWMUs) for the Middle Hoh WAU are shown on Map A-2 and in Table 2. These eight MWMUs have been delimited to represent mass wasting process, density and lithology. Summary statistics for each MWMU are in Form A-2. Table 2: Area (acres) of Mass Wasting Map Units by Middle Hoh WAU Sub-basins Sub-basin MWMU1 MWMU2 MWMU3 MWMU4 MWMU5 MWMU6 MWMU7 MWMU8 Total Alder 580.6 43.8 4.9 17.9 0.0 0.0 53.6 2829.1 3529.9 Elk 1796.7 0.0 122.7 255.6 7.4 9.4 295.0 9094.9 11581.8 Hell Roaring 96.5 91.6 0.0 96.5 0.0 0.0 16.4 3631.9 3932.9 Owl 3545.5 0.0 68.0 216.9 0.0 10.1 255.0 4280.5 8376.1 South Fork 2746.5 0.0 0.0 135.2 26.5 77.5 86.1 3858.1 6929.7 Spruce 1579.8 0.0 0.0 119.3 0.0 13.2 246.2 2209.6 4168.2 Tower 1149.4 0.0 0.0 154.7 0.0 0.0 43.9 2571.3 3919.2 Willoughby 1205.1 0.0 0.0 136.2 0.0 0.0 204.1 2607.9 4153.2 Winfield 362.3 1291.8 0.0 87.4 0.0 15.7 431.1 5568.5 7756.7 54347.7 Total 13062.4 1427.2 195.6 1219.6 33.8 126.0 1631.4 36651.7 54347.7 Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module MWMU1: Willoughby-Huelsdonk Headwaters MWMU1 occurs in the steep(50-126%) and convergent topography within the Western Olympic Lithic Assemblage rocks in the upper reaches of Alder, Elk, Hell Roaring, Owl, South Fork, Spruce, Tower, Willoughby and Winfield sub-basins. MWMU1 is the largest MWMU in the WAU and has the highest number of shallow rapid and debris flow mass wasting events of all MWMUs. MWMU1 has the second largest area of landslides of the MWMUs (Figure 4). Mass wasting in MWMU1 is concentrated in convergent “headwalls” near the upper limits of stream channel catchments and in incised “inner gorge” topography adjacent to stream channels. Soils are typically shallow (less than 5 feet) and have a roughly 30-70 bimodal distribution of cobble and fines. Parent material is deformed sandstone and conglomerate. The elevation of MWMU1 ranges from 520 feet to 3480 feet. MWMU1 has been historically sensitive to clear-cutting and road construction with 80% of all inventoried landslides associated with these two types of forest practices. The delivery potential of mass wasting occurring in MWMU1 is high, with 95% of all landslides delivering material to surface waters. MWMU1 is rated as having a High mass wasting potential with an observed landslide rate of 9.98 landslides per year between 1939 and 1999. MWMU2: Winfield MWMU2 occurs in the steep (55%-115%) and convergent topography within the Hoh Lithic Assemblage rocks in the upper reaches of the Winfield sub-basin and in the lower areas of Alder and Hell Roaring sub-basins associated with the Hoh Oxbow. Mass wasting is dominated by shallow rapid and debris flow events occurring in steep convergent headwalls and in stream adjacent inner gorge hillslopes. This MWMU is very similar to MWMU1 except for the difference in underlying rock formation. Soils are typically shallow (less than 5 feet deep) with fewer cobbles and more fines. The elevation of MWMU2 ranges between 200 and 2000 feet and has a total area of 1427.2 acres. Mass wasting in MWMU2 is dominated by shallow rapid landslides and debris flows. MWMU2 is very sensitive to forest practice effects with 80% of the observed landslides associated with either clear-cut timber harvest or roads. The delivery potential of MWMU2 is very high with 98% of all landslides entering surface waters. The mass wasting potential of MWMU2 is high with an observed landslide rate of 2.2 landslides per year between 1975 and 1999. MWMU3: Western Olympic Deep-seated. MWMU3 primarily occurs in Owl Creek occurring on lower valley side-slopes and inner gorges adjacent to Owl Creek mainstem and tributaries (Map A-2). MWMU3 is associated with structural faulting of the Western Olympic assemblage rock unit (sandstone and conglomerate) and has typically shallow soils with a bimodal distribution of cobble and fines. Slope angles range between 50% and 106%, and the elevation of the unit ranges between 1200 and 2400 feet. The mass wasting processes are deep-seated mass movement associated with structural faulting. These deep-seated landslides appear to have been triggered by disturbance from multiple debris flow events and dam-break floods along the inner gorge of Owl Creek. MWMU3 is also sensitive to increased water delivery from road system drainage. MWMU4: Glacial Gorges This map unit occupies short, moderate to very steep glacial and alluvial terrace margins and inner gorges of streams with in the Olympic alpine glacial rock units. Parent materials are composed of glacial moraines and stratified outwash, till and dead-ice deposits and may include alluvial terraces along major river channels not associated with glaciation. Soils in this unit are relatively deep (>5 feet) and are predominantly non-cohesive with a 15-85 bimodal distribution of cobbles to fines. Hillslope morphology in this unit is generally planar, but convergent hollows developed in longer glacial hillslopes may also be included. Mass wasting occurs as shallow rapid landslides with no observed debris flow events. Some limited areas of small sporadic deep seated landslides may be present in this unit as Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module mapped. Sensitivity to forest practices land uses is high with 96% of observed failures associated with road construction and clear-cut timber harvest. Triggering mechanisms for hillslope failure include loss of root strength, sidecast road construction, and inadequate road drainage. MWMU5: Mainstem Terrace Faces MWMU5 is found on short, very steep glacial and alluvial terrace margins along the mainstem and South Fork Hoh river channels. Mass wasting processes included shallow rapid and block fall type movements. Parent materials are deposits of Olympic alpine glaciers including moraines, till and outwash deposits. Soils are relatively thick and non-cohesive. MWMU5 is highly sensitive to forest practice activities with 100% of observed landslides associated with either road construction or clear-cut timber harvest. Channel migration and undercutting of slope toes may be a contributing factor to mass wasting in this unit. MWMU6: Mainstem Deep Seated MWMU6 includes deep-seated block-glide and earthflow type landslides associated with glacial and alluvial terraces adjacent to the mainstem and South Fork Hoh River. Lacustrine clayey silt layers in glacial deposits form the slip plane for these failures and channel migration of the river channel is the dominant triggering mechanism. Road and skid trail construction and timber harvest has increased runoff delivery to these landslides but it is unclear to what extent these factors control the movement of individual landslides. Roughly ½ of observed landslides in this unit were associated with forest practice activities and 86% of observed landslides delivered materials to streamchannels. MWMU7: Deep Seated Landslides inventoried by Gerstel, 1999. This unit contains large persistent deep seated landslides associated with both older sedimentary rocks of the Hoh and Olympic Lithic Assemblage and a variety of glacial materials distributed through out the Middle Hoh WAU including younger glacio-lacustrine and till deposits. This unit occurs on typically convergent and planar valley sideslopes or convergent headwater hillslopes. This unit was not assessed for sensitivity of landuse. Roughly 94% of landslides in this unit deliver materials to streamchannels. MWMU8: Low Hazard Areas This unit encompasses low gradient areas of intermediate ridgetops, valley sidewalls and valley floors and is composed primarily of Olympic alpine glacial deposits, with minor areas of Western and Hoh lithic assemblage rocks on intermediate ridges and valley sidewalls. Slopes range between 0-50%, with minor inclusions of steeper (100%) slopes where delivery of mass wasting products is limited. The elevation of this unit ranges between 280-2800 feet. Mass wasting observed in this unit is shallow rapid triggered by high intensity rainfall, soil creep and natural disturbance. The distribution of landslides by Mass Wasting Map Unit is shown in Figure 3. In terms of raw numbers of landslides, MWMU1 is clearly the most productive of all the MWMUs followed by MWMU2, MWMU4, MWMU7, MWMU6, MWMU5, MWMU3, and MWMU8. Because there is no direct relation between the number of landslides observed and the amount or effect of delivered materials to surface waters, the area of observed landslides for each MWMU area was calculated (Figure 4). This was done to relate the magnitude of observed landsliding among MWMUs. In doing this it is important to keep in mind that differing mass wasting processes have varying effects on the delivery of water, wood, sediment and energy to stream channels. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 0 100 200 300 400 500 600 MWMU1 MWMU2 MWMU3 MWMU4 MWMU5 MWMU6 MWMU7 MWMU8 Mass Wasting Map Unit Middle Hoh WAU Landslides by Mass Wasting Map Unit Figure 3: Distribution of landslides observed in the Middle Hoh WAU by Mass Wasting Map Unit (MWMU). Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module MWMUs 1, 2, and 4 have the greatest potential for mass wasting delivered to low order tributary channels through 0 250 500 750 1000 1250 1500 1750 2000 MWMU1 MWMU2 MWMU3 MWMU4 MWMU5 MWMU6 MWMU7 MWMU8 Mass Wasting Map Unit Middle Hoh WAU Landslide Area (ac.) by MWMU Figure 4: Area of observed landslides (acres) by Mass Wasting Map Unit. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module shallow rapid landslides, debris flows and debris dam-break floods with fluvial routing to larger mainstem systems. MWMUs 3, 5, 6 & 7 route mass wasting products primarily to mainstem river channels through slower earthflow and block-glide processes. MWMUs 1,2, 4, and 5 are the most sensitive in terms of triggering mechansims associated with forest practices while MWMUs 2, 6, & 7 are the least sensitive (excluding MWMU 8) to the effects of individual forest practice activities. 6.0 Summary of Critical Questions In order to explicitly address the critical questions posed my the Standard Methods for Conducting Watershed Analysis, the following summaries are included: What are the potential sediment sources in the basin? Potential sediment sources in the basin include fluvial transport of bed and washload in the Main and South Fork river channels, sediment production from hillslopes (Map A-1 & A-2, Appendix A, Form A-1), sediment production from road systems (see Appendix B, Surface Erosion Assessment), and aeolian transport of fine sediment from the atmosphere. Is there evidence of, or potential for mass wasting in the watershed? Yes. Map A-1 and A-2, Form A-1. Mass wasting rates assessed in the Middle Hoh WAU on average are equivalent with those observed in the North Cascades (Eide, 1990; Parks 1992) and in other Olympic Peninsula watersheds (O’Connor 1993). What mass wasting processes are active? Shallow rapid landsliding, debris flows and debris-dam break floods, deep-seated landsliding, including earth flows and translational block-glide type failure processes are active in the Middle Hoh WAU (Map A-1& A-2, Form A-1). How are mass wasting features distributed throughout the landscape? See Map A-1. What physical characteristics are associated with these features? See Map A-1 and Form A-2. Shallow rapid landslide processes occur on hillslopes between 50%-126% in convergent headwall and inner gorge landforms in marine sedimentary and glacial lithology. Deep seated landslides occur on less (12%-106%) steep hillslopes associated with structural weaknesses (folding and faulting) and glacial stratigraphy (clay/silt& sand layers)., Do landslides deliver sediment to stream channels or other waters? Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module On average, landslides observed in the Middle Hoh WAU deliver sediment to stream channels or other waters 86% of the time. Do forest management activities create or contribute to instability? Yes. 82% of observed landslides in the Middle Hoh WAU were associated with forest practice activity. Clear-cut timber harvesting on steep hillslopes, sidecast road construction techniques, and poor road drainage design all contribute to hillslope instability. What areas of the landscape are susceptible to slope instability? Steep convergent headwater areas of zero, 1st and 2nd order streamchannels, steep planar hillslopes adjacent to stream channels, and steep glacial and alluvial terrace deposits are susceptible to shallow rapid and debris flow mass wasting processes. Areas of structural faulting and folding and/or glacial stratigraphy underlain by glacial silt and clay are susceptible to deep-seated mass wasting processes. See Map A-1 and Map A-2. What is the relative contribution of sediment from mass wasting compared with other sources? The Hoh River transports and estimated mean of 630,000 (t/yr) tons of sediment annually (Nelson 1986). The Surface Erosion Assessment (Appendix B) estimates the fine sediment production from hillslopes in the Middle Hoh WAU is 1739 (t/yr) and from roads 2147 (t/yr). Coarse sediment production from mass wasting in the Huelsdonk Ridge area of the Middle Hoh WAU was estimated by Logan et al., 1991, to be 286 m3/km/yr which works out to be approximately 94,350 t/yr if distributed across the Middle Hoh WAU area. Given that rates of observed landslides in other sub-basins in the Middle Hoh WAU are less than those observed in the Huelsldonk Ridge area, the overall sediment production rate from mass wasting is likely less than the estimate given by Logan et al. 1991. However, sediment production estimates for other Olympic Peninsula watersheds suggest that Logan’s estimate is probably realistic for disturbed watersheds. O’Connor reports a sediment production rate from mass wasting in the North Fork Calawah Watershed to be 260 m3/km2/yr. Sediment production from mass wasting in colluvial hollows in the Clearwater River watershed was estimated to be 173 m3/km2/yr (Reneau and Dietrich, 1989). Based on the sediment production values given above, it is estimated that sediment production from mass wasting represents about 24 times the sediment production from surface and road erosion in the Middle Hoh WAU. 7.0 Confidence in Work Products There are several sources of systematic error that reduce the confidence in the work products of this analysis; those being omission, misinterpretation, accuracy and precision. Omission occurs when mass wasting features are not identified on aerial photographs or in the field due to canopy cover, photo quality or user error. Misinterpretation occurs when a mass wasting feature is identified but incorrectly classified. Accuracy involves the degree to which the physical parameters of a mass wasting feature are correctly measured, and precision describes how variability within an assessment can be controlled when making multiple measurements over varying time and spatial scales. Because the data used to interpret mass wasting processes was largely obtained using remote methods (aerial photograph interpretation) there is a high likelihood that errors of omission occurred primarily in the interpretation of the 1939 USGS photographs due to the presence of an old-growth canopy. Given a mature canopy, the minimum size Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module of visible mass wasting features is controlled by gaps in the foliage, so that only larger mass wasting features remain visible. As the percentage of young forest increases through air photo sets, the potential for missing landslides is reduced. The bulk of mass wasting features mapped in this analysis were recorded under young canopy conditions, therefore the potential for omitting a large number of landslides is small. The resulting assessment of mass wasting processes is therefore rated with a high level of confidence. The second source of error, misinterpretation, or incorrect classification is likely a minimal source of error with respect to debris flow and shallow rapid landsliding and a source of moderate error with respect to deep-seated landslide processes. Because many deep-seated landslides remain heavily vegetated as they move, may not have obvious landslide scars, and can involve relatively large land areas, mis-interpretation of these feature is more likely. Therefore confidence in work products related to classification of landslide process is moderate. The third main source of error in this analysis is in the accuracy and precision of measurements of landslides made from aerial photographs. Because the aerial photographs used in this analysis vary in quality and scale, it is possible that similar measurements made from different air photos have differing levels of measurement error. Because only very few landslides were visited in the field and no landslides were surveyed using highly precise measurement techniques such Global Positioning Systems, theodolites, or even compass traversing, it is not possible to report the degree to which measurement error across aerial photographs is propagated. It is likely that measurements of landslide area made from the 1939 air photo series is less accurate than measurments made from the 1975, and 1998 air photos simply on the basis of scale alone. Similarly, measurements of slope angles from topographic maps typically mis-represent the true hillslope angle at a site to within +/- 10-20%. Given these sources of error, I would rate the confidence in the measurements of individual landslides as moderate. 8.0 Appendix A-1 8.1 References Amerman, K.S. and J.F. Orsborn. 1987. An Analysis of Streamflows on the Olympic Peninsula in Washington State. Albrook Hydraulics Laboratory. Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington. Benda, L.E. and T.W. Cundy. 1990. Predicting depostion of debris flows in mountain channels. Can. Geotech. J. Vol. 27. pp. 409-417. Brandon, M.T., M.K. Roden-Tice, and J.I. Garver. 1998. Late Cenozoic exhumation of the Cascadia accretionary wedge in the Olympic Mountains, northwest Washington State. GSA Bulletin, V.110; no. 8; p.985-1009. Coates, D. R. 1990. The relation of subsurface water to downslope movement and failure, in Higgins, C.G., and Coates, D.R., eds. Groundwater geomorphology; The role of subsurface water in Earth-surface processes and landforms; Boulder, Colorado, Geological Society of America Special Paper 252. Dieu, J. & W. Shelmerdine. 1997. Module A-Sedimentation assessment. In Pentec Environmental, Inc., North Fork Calawah Watershed Analysis, WAU 200315-Final Report: Penten Environmental, Inc. [under contract to] Rayonier Timberlands Operating Company, 1v. Edmonds, R.L. and R.D. Blew. 1997. Trends in Precipitation and Stream Chemistry in a Pristine Old-Growth Forest Watershed, Olympic National Park, Washington. Journal of the American Water Resources Association.Vol. 33, No. 4. Pp. 781-794. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Eide, J. 1990. A 48-year sediment budget (1942-1989) for Deer Creek Basin, Washington. M.S. Thesis, Western Washington University, Bellingham, Washington. 122 pp. Fiksdal, A. J. and M. J. Brunengo. 1980. Forest Slope Stability Project, Phase I: Washington Department of Ecology Technical Report 80-2a, 18p., 7 plates. Gerstel, W.J. 1999. Deep-Seated Landslide Inventory of the West-Central Olympic Peninsula. Open File Report 99-2. Washington Division of Geology and Earth Resources. Washington State Department of Natural Resources. Olympia, Washington. 36 pp., 2 plates. Ginn, Shannon. 1996. The impact of land use practices and hydrology on a slump-earthflow landslide, Olympic Peninsula, Washington: Carleton College Senior Integrative Exercise [thesis], 48 p. Grant. G.E. and F.J. Swanson. 1995. Morphology and processes of valley floors in mountain streams, Western Cascades, Oregon. In. Natural and Anthropogenic Influences in Fluvial Morphology. Geophysical Monograph 89. American Geophysical Union. Pp. 83-101. Haneberg, W.C., 1995. Groundwater flow and the stability of heterogeneous infinite slopes underlain by impervious substrata, in Haneberg, W.C. and Anderson, S.A., eds., Clay and Shale Slope Instability: Boulder, Colorado, Geological Society of America Reviews in Engineering Geology, v. X. Hatten, J. 1991. The Effects of Debris Torrents on Spawning Gravel Quality in Tributary Basins ans Side-channels of the Hoh River, Washington. Unpublished Report. Hoh Indian Tribe. Forks, Washington. 19 pp. Heusser, C.J. 1974. Quaternary vegetation, climate, and glaciation of the Hoh River Valley, Washington. Geol. Soc. America Bull., v.85, p.1547-1560. Howard, A.D. 1998. Long profile development of bedrock channels: interactions of weathering, mass wasting, bed erosion, and sediment transport. In: Rivers Over Rock: Fluvial Processes in Bedrock Channels. Geophysical Monograph 107. American Geophysical Union. pp 297-319. Johnson, D.M. and R. W. Koch. 1992. Climate and Streamflow of the Pacific Northwest: Teleconnections with the Tropical Pacific Ocean. 1992. Interdisciplinary Approaches in Hydrology and Hydrogeology. American Institute of Hydrology, pp. 406-426. Kresch, D.L. and T.C. Pierson. 1987. Flood hazard Assessment of the Hoh River at Olympic National Park Ranger Station, Washington. Water Resources Investigations Report 86-4198. U.S. Geological Survey. U.S Department of Interior Washington D.C. Lingley, L.L., 1998. Mass Wasting Inventory Map. In U.S. Forest Service, 1998, Sitkum and South Fork Calawah Watershed Analysis: U.S. Forest Service. 1 v. Logan, R.L., K.L. Kaler, and P.K. Bigelow. 1991. Prediction of Sediment Yield From Tributary Basins Along Huelsdonk Ridge, Hoh River, Washington. Washington Division of Geology and Earth Resources, Open File Report 91-7. Lum. W.E., and L.M. Nelson. 1986. Reconnaissance of the Water Resources of the Hoh Indian Reservation and the Hoh River Basin, Washington. Water-Resources Investigations Report 85-4018. United States Geological Survey, U.S. Department of the Interior. Tacoma, Washington. McCreary, F.R. 1975. Soil Survey of Jefferson County Area, Washington. United States Department of Agriculture, Soil Conservation Service In cooperation with Washington Agricultural Experiment Station. U.S.D.A., Washington, Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module D.C. 20250. McHenry, M. 1991. The Effects of Debris Torrents on Macroinvertebrate Populations in Tributary Basins of the Hoh River, Washington. Unpublished Report. Northwest Indian Fisheries Commission, Box 1029, Forks, Washington. 26 pp. Michalowski, R.L. 1995. Stability of slopes: Limit analysis approach. In: Haneber, W.C., and Anderson, S.A., eds., Clay and Shale Slope Instability; Boulder, Colorado, Geological Society of America Reviews in Engineering Geology. Montgomery, D.R. 1994. Road surface drainage, channel initiation, and slope instability. Water Resources Research, Vo. 30. No. 6., pp. 1925-1932. Montgomery, D.R. and W.E. Dietrich. 1994. A physically based model for the topographic control on shallow landsliding. Water Resources Research, Vol. 30, No. 4. pp 1153-1171. O’Connor, M. and T.W. Cundy. 1993. North Fork Calawah River Watershed Condition Survey: Landslide Inventory and Geomorphic Analysis of Mainstem Alluvial System. Part I: Landslide Inventory and Geomorphic Analysis of Mass Erosion. U.S.D.A. Forest Service. Reid, L.R. 1981. Sediment Production from Gravel-surfaced roads, Clearwater Basin, Washington, Final Report, FRI-UW-8108. University of Washington, Washington Fisheries Research Institute. Reid, L.R. and T. Dunne. 1984. Sediment Production From Forest Road Surfaces. Water Resources Research. Vol. 20, No. 11, Pages 1753-1761. Reneau, S.L. and W.E. Dietrich. 1989. Depositional History of Hollows on Steep Hillslopes, Coastal Oregon and Washington. National Geographic Research 6(2): 220-230. Serder, C.F. , 1997. Description, analysis, and impact of the Grouse Creek landslide, Jefferson Co. Washington. Evergreen State College Master of Environmental Studies thesis. 1 v. Swanson, F.J. and G.W. Lienkaemper. 1982. Interactions among fluvial processes, forest vegetation and aquatic ecosystems, South Fork Hoh River, Olympic National Park. In. Ecological Research in National Parks of the Pacific Northwest. Oregon State University Forest Research Laboratory Publication, Corvallis, Oregon, 97331. Thrackray, G.D. 1996. Glaciation and Coastal Neotectonic Deformation on the Western Olympic Peninsula, Washington. 1996 Pacific Northwest Cell Field Conference Guidebook. Department of Geology, Idaho State University. Pocatello, ID 83209. Tabor and Cady 1978. Geologic Map of the Olympic Peninsula, Washington. Department of the Interior, United States Geologic Survey. Map I-994. Miscellaneous Investigations Series. Washington, D.C. Wells, R.E., C.S. Weaver, and R.J. Blakely. 1998. Fore-arc migration in Cascadia and its neotectonic significance. Geology. August 1998. V. 26, no. 8, p. 759-762. WFPB 1995. Washington Forest Practices Board, Standard Methodology for Conducting Watershed Analysis.Version 4.0. Washington Department of Natural Resources. Olympia, Washington. Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module 8.2 Forms Form A-1 Mass Wasting Inventory Data Organized by MWMU. Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Alder Creek 1939 AC-1 1 SR/1 0.39 Y C43 OGF 90 c Tur 1680 Channel Adjacent Failure Alder Creek 1939 AC-2 1 SR/1 1.24 Y C42 OGF 80 c Tur 2000 Headwall failure Alder Creek 1939 AC-3 1 DBF/1 1.48 Y C49 OGF 80 c Tur 1240 Headwall failure Alder Creek 1939 AC-4 1 SR/1 0.78 Y C50 OGF 90 p Tur 1080 Divergent hillslope, inner gorge toe slope Alder Creek 1939 AC-5 1 SR/1 0.74 Y C50 OGF 80 d Tur 920 Divergent hillslope, inner gorge toe slope Alder Creek 1939 AC-6 1 SR/1 1.14 Y C33 OGF 90 c Tur 1160 Convergent hillslope, channel head failure Alder Creek 1939 AC-7 1 SR/1 0.45 Y C30 OGF 85 c Tur 1240 Convergent hillslope, channel head failure Alder Creek 1975 AC-1 1 SR/d 1.17 Y C47 R 100 P Two 1240 H3220 sidecast Alder Creek 1975 AC-2 1 SR/DBF 0.43 Y C49 CC 65 C Two 1560 In Unit Hollow failure Alder Creek 1975 AC-3 1 SR/DBF 0.32 Y C39 R 65 C Two 1440 H3220 sidecast Alder Creek 1975 AC-4 1 SR/DBF 1.00 Y C41 R 85 D Two 1400 H3220 sidecast Alder Creek 1975 AC-5 1 SR/d 0.37 Y C50 R 65 P Two 960 H3220 sidecast Alder Creek 1998 AC-1 1 SR/d 0.26 Y C46 CC 55 C Thts 1920 INNER GORGE UPPER ALDER CREEK Alder Creek 1998 AC-2 1 SR/d 0.20 Y C46 CC 75 C Thts 1840 INNER GORGE UPPER ALDER CREEK Alder Creek 1998 AC-3 1 SR/d 0.32 Y C46 CC 75 C Thts 1840 INNER GORGE UPPER ALDER CREEK Alder Creek 1998 AC-4 1 DBF/d 1.84 Y C46 CC 55 D Thts 1880 IN UNIT HOLLOW FAILURE Alder Creek 1998 AC-5 1 SR/d 0.48 Y C46 CC 65 D Thts 1720 IN UNIT HOLLOW FAILURE Alder Creek 1998 AC-6 1 DBF/d 1.90 Y C46 CC 65 C Thts 1880 IN UNIT HOLLOW FAILURE Alder Creek 1998 AC-7 1 SR/d 1.02 Y C48 CC 55 C Thts 1640 IN UNIT HOLLOW FAILURE Alder Creek 1998 AC-8 1 DBF/d 6.70 Y C42 CC 65 C Thts 2120 LARGE HOLLOW FAILURE Alder Creek 1998 AC-9 1 DBF/d 2.94 Y C44 CC 75 C Thts 1720 LARGE HOLLOW FAILURE Alder Creek 1998 AC-10 1 DBF/d 0.52 Y C41 R 65 D Thts 1480 ROAD CUTSLOPE FAILURE Alder Creek 1998 AC-11 1 DBF/d 1.55 Y C98 R 55 C Thts 1320 ROAD FILLSLOPE FAILURE Alder Creek 1998 AC-12 1 SR/d 0.20 Y C41 CC 75 C Thts 1000 INNER GORGE FAILURE Alder Creek 1998 AC-13 1 DBF/d 1.60 Y C38 R 65 C Thts 1320 ROAD FILLSLOPE FAILURE IN HOLLOW Alder Creek 1998 AC-14 1 SR/d 0.40 Y C41 CC 110 C Thts 920 SMALL INNER GORGE FAILURE Alder Creek 1998 AC-15 1 SR/d 0.72 Y C32 CC 65 C Thts 1240 IN UNIT FAILURE FROM HOLLOW Alder Creek 1998 AC-16 1 DBF/d 0.12 Y C32 CC 65 P Thts 1160 SMALL HOLLOW FAILURE Alder Creek 1998 AC-17 1 DBF/d 1.34 Y C31 R 65 C Thts 1360 ROAD FILLSLOPE FAILURE IN HOLLOW Alder Creek 1998 AC-18 1 SR/d 0.55 Y C33 CC 65 C Thts 1120 IN UNIT HOLLOW FAILURE Elk Creek 1975 EC-1 1 DBF/d 0.28 Y C607 R 85 D Twot 2640 H1600 Sidecast Elk Creek 1975 EC-2 1 SR/d 1.11 Y C606 CC 85 C Twot 1840 Elk Creek 1975 EC-3 1 DBF/d 0.50 Y C610 R 90 C Twot 2160 Elk Creek 1975 EC-4 1 DBF/d 1.07 Y C610 R 85 C Twot 2120 H1600 Sidecast Elk Creek 1975 EC-5 1 DBF/d 0.90 Y C610 R 90 C Twot 2120 H1600 Sidecast Elk Creek 1975 EC-6 1 SR/d 0.88 Y C612 R 90 D Twot 1840 H1600 Sidecast Elk Creek 1975 EC-7 1 SR/d 0.41 Y C612 R 65 D Twot 1800 H1600 Sidecast Elk Creek 1975 EC-8 1 SR/d 0.39 Y C612 R 65 D Twot 1720 H1600 Sidecast Elk Creek 1975 EC-9 1 DBF/d 3.58 Y C611 L 85 C Twot 2240 H1600 Sidecast Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Elk Creek 1975 EC-10 1 DBF/d 1.90 Y C611 CC 90 C Twot 1840 H1540 /perched landing Elk Creek 1975 EC-11 1 SR/d 0.24 Y C611 CC 70 P Twot 1480 Elk Creek 1975 EC-12 1 DBF/d 5.82 Y C623 L 85 C Twot 2280 H1540 /huge debris flow Elk Creek 1975 EC-13 1 DBF/d 0.44 Y C623 R 70 D Twot 2560 H1540 spur Elk Creek 1975 EC-14 1 DBF/d 0.39 Y C623 R 80 C Twot 2560 H1540 Elk Creek 1975 EC-15 1 DBF/d 0.42 Y C623 R 85 C Twot 2600 H1540 Elk Creek 1975 EC-16 1 DBF/d 0.44 Y C623 R 80 C Twot 2600 H1540 Elk Creek 1975 EC-17 1 SR/d 0.34 Y C622 OGF 65 C Twot 1880 Elk Creek 1975 EC-18 1 SR/d 0.28 Y C624 OGF 55 C Twot 1200 Undercut by EC-12 debris flow Elk Creek 1975 EC-19 1 SR/d 0.19 Y C627 CC 75 C Twot 1200 Small in unit failures Elk Creek 1975 EC-20 1 SR/d 0.32 Y C627 CC 75 C Twot 1240 Small in unit failures Elk Creek 1975 EC-21 1 SR/d 0.79 N NA R 85 D Twot 1080 H1610 sidecast Elk Creek 1975 EC-22 1 SR/d 1.01 Y C638 R 90 C Twot 2440 H1500 sidecast Elk Creek 1975 EC-23 1 SR/d 0.24 Y C630 OGF 90 P Twot 1600 Elk Creek 1975 EC-24 1 SR/d 0.40 Y C629 OGF 100 P Twot 1400 Elk Creek 1975 EC-25 1 SR/d 0.24 Y C629 OGF 100 P Twot 1360 Elk Creek 1975 EC-26 1 SR/d 0.25 Y C629 OGF 75 P Twot 1040 Elk Creek 1975 EC-27 1 SR/d 0.16 Y C639 OGF 100 P Twot 1640 Elk Creek 1975 EC-28 1 SR/d 2.57 Y C637 OGF 75 P Twot 1440 Elk Creek 1975 EC-29 1 SR/d 1.17 Y C642 R 75 C Twot 1560 H1500 upper west fork dry creek Elk Creek 1975 EC-30 1 SR/d 0.93 Y C642 R 75 C Twot 1520 H1500sidecast Elk Creek 1975 EC-31 1 SR/d 0.18 Y C648 R 80 C Twot 1240 H1500 sidecast Elk Creek 1975 EC-32 1 SR/d 1.00 Y C645 R 100 C Twot 1240 H1500 sidecast Elk Creek 1975 EC-33 1 SR/d 0.26 N NA R 75 D Twot 1200 H1521 sidecast Elk Creek 1975 EC-34 1 DBF/d 0.09 Y C648 R 75 D Twot 1720 H1521 sidecast Elk Creek 1975 EC-35 1 SR/d 0.15 Y C650 R 75 C Twot 1560 Elk Creek 1975 EC-36 1 SR/d 0.19 Y C650 CC 75 C Twot 1480 Dry Creek Pit fillslope Elk Creek 1975 EC-49 1 DBF/d 1.81 Y C620 R 105 C Two 1480 H1600 Sidecast Elk Creek 1975 EC-50 1 DBF/d 1.12 Y C620 R 105 C Two 1520 H1600 Sidecast Elk Creek 1998 EC-1 1 DBF/d 3.10 Y C616 CC 85 C Two 2480 HOLLOW FAILURE TO BIG DBF Elk Creek 1998 EC-2 1 DBF/d 16.81 Y C616 CC 75 C Two 2280 HOLLOW FAILURE TO BIG DBF Elk Creek 1998 EC-3 1 DBF/d 10.58 Y C609 R 75 C Two 2240 ROAD FILLSLOPE FAILURE TO BIG DBF Elk Creek 1998 EC-4 1 DBF/d 2.97 Y C605 R 85 P Two 2600 ROAD FILLSLOPE FAILURE TO BIG DBF Elk Creek 1998 EC-5 1 DBF/d 2.97 Y C605 R 75 D Two 2520 ROAD FILLSLOPE FAILURE TO BIG DBF Elk Creek 1998 EC-6 1 DBF/d 2.25 Y C605 CC 85 D Two 2360 HOLLOW FAILURE Elk Creek 1998 EC-7 1 DBF/d 0.38 Y C608 CC 65 C Two 1960 HOLLOW FAILURE Elk Creek 1998 EC-8 1 SR/d 0.29 Y C608 CC 65 C Two 1720 INNER GORGE FAILURE Elk Creek 1998 EC-9 1 SR/d 0.76 Y C608 CC 75 C Two 1880 INNER GORGE FAILURE Elk Creek 1998 EC-10 1 SR/d 2.85 Y C610 R 85 C Two 2240 BIG UGLY FILLSLOPE FAILURE Elk Creek 1998 EC-11 1 SR/d 4.83 Y C610 R 110 C Two 2240 BIG UGLY FILLSLOPE FAILURE Elk Creek 1998 EC-12 1 SR/d 0.74 Y C610 R 85 C Two 1880 HOLLOW FAILURE BELOW ROAD CROSSING Elk Creek 1998 EC-13 1 SR/d 0.45 Y C612 R 75 P Two 1800 FILLSLOPE FAILURE Elk Creek 1998 EC-14 1 SR/d 0.63 Y C612 CC 75 P Two 1800 IN UNIT HOLLOW FAILURE Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Elk Creek 1998 EC-15 1 SR/d 0.61 Y C612 CC 85 P Two 1640 IN UNIT HOLLOW FAILURE Elk Creek 1998 EC-16 1 DBF/d 2.25 Y C605 CC 85 C Two 2160 HOLLOW FAILURE Elk Creek 1998 EC-17 1 DBF/d 0.57 Y C605 CC 75 C Two 1840 HOLLOW FAILURE Elk Creek 1998 EC-18 1 DBF/d 4.95 Y C605 L 115 D Two 2280 OLD FAILURE, RECENT REACTIVATION Elk Creek 1998 EC-19 1 SR/d 3.93 Y C611 CC 85 C Two 2240 HOLLOW FAILURE Elk Creek 1998 EC-20 1 SR/d 1.25 Y C611 CC 85 C Two 1960 HOLLOW FAILURE Elk Creek 1998 EC-21 1 DBF/d 1.72 Y C612 R 85 C Two 1600 HOLLOW FAILURE BELOW ROAD CROSSING Elk Creek 1998 EC-22 1 DBF/d 8.65 Y C623 R 75 C Two 2360 ROAD FILLSLOPE FAILURE Elk Creek 1998 EC-23 1 DBF/d 0.71 Y C623 CC 75 C Two 2360 HOLLOW FAILURE Elk Creek 1998 EC-24 1 DBF/d 1.43 Y C623 CC 85 C Two 2440 HOLLOW FAILURE Elk Creek 1998 EC-25 1 DBF/d 0.17 Y C623 CC/R 75 C Two 2560 HOLLOW FAILURE BELOW ROAD CROSSING Elk Creek 1998 EC-28 1 SR/d 1.74 Y C628 CC 75 C Two 1240 Elk Creek 1998 EC-29 1 SR/d 2.77 Y C625 R 85 P Two 1840 ROAD FILLSLOPE FAILURE Elk Creek 1998 EC-30 1 SR/d 1.62 Y C625 R 85 P Two 1800 ROAD FILLSLOPE FAILURE Elk Creek 1998 EC-31 1 SR/d 0.22 Y C626 CC/R 55 C Two 1160 HOLLOW ABOVE CUTSLOPE Elk Creek 1998 EC-34 1 DBF/d 2.81 Y C632 CC 65 C Two 1600 HOLLOW FAILURE INTO TRIB OF MAPLE Elk Creek 1998 EC-35 1 SR/d 8.18 Y C603 CC 55 C Two 1160 INNER GORGE FAILURE ON TRIB. TO MAPLE Elk Creek 1998 EC-37 1 DBF/d 2.14 Y C648 R 75 C Two 2040 ROAD FILLSLOPE FAILURE AT STREAM CROSSING Elk Creek 1998 EC-38 1 SR/d 0.94 Y C636 CC 100 P Two 1520 INNER GORGE UPPER DRY CREEK Elk Creek 1998 EC-39 1 SR/d 0.40 Y C636 CC 55 D Two 1440 INNER GORGE UPPER DRY CREEK Elk Creek 1998 EC-40 1 SR/d 0.50 Y C636 CC 105 D Two 1400 INNER GORGE UPPER DRY CREEK Elk Creek 1998 EC-41 1 DBF/d 1.91 Y C642 CC 65 C Two 2080 HOLLOW FAILURE UPPER DRY CREEK Elk Creek 1998 EC-42 1 DBF/d 0.81 Y C642 CC 85 C Two 2000 HOLLOW FAILURE UPPER DRY CREEK Elk Creek 1998 EC-43 1 SR/d 0.52 N NA CC 65 P Two 1520 IN UNIT FAILURE ABOVE DRY CREEK Elk Creek 1998 EC-44 1 SR/d 0.20 Y C649 CC/R 75 C Two 1520 HOLLOW FAILURE ABOVE ROAD CROSSING Elk Creek 1998 EC-45 1 SR/d 0.42 Y C649 CC 65 C Two 1440 INNER GORGE FAILURE Elk Creek 1998 EC-46 1 DBF/d 8.02 Y C647 R 65 C Two 1560 BIG NASTY FILLSLOPE FAILURE DRY CREEK Elk Creek 1998 EC-47 1 DBF/d 0.64 Y C648 R 85 C Two 1720 ROAD FILLSLOPE Elk Creek 1998 EC-64 1 SR/d 0.50 Y C715 CC 65 C Two 1240 UPPER ELK CREEK HOLLOW FAILURE Elk Creek 1998 EC-65 1 SR/d 0.26 Y C715 CC 65 C Two 1200 HOLLOW FAILURE Elk Creek 1998 EC-66 1 SR/d 0.26 Y C715 CC 65 C Two 1200 HOLLOW FAILURE Elk Creek 1998 EC-67 1 SR/d 0.73 Y C715 CC 75 C Two 1160 HOLLOW FAILURE Hell Roaring 1998 HR-3 1 SR/d 0.42 Y C13 CC 55 P Qo 840 INNER GORGE FAILURE Hell Roaring 1998 HR-4 1 DBF/d 0.23 Y C16 CC 65 D Qo 920 SMALL IN UNIT HOLLOW FAILURE Hell Roaring 1998 HR-5 1 DBF/d 0.26 Y C16 CC 65 P Qo 920 SMALL IN UNIT HOLLOW FAILURE Hell Roaring 1998 HR-6 1 SR/d 0.17 Y C18 CC 65 C Qo 1040 SMALL HOLLOW FAILURE Hell Roaring 1998 HR-7 1 SR/d 0.18 Y C18 CC 55 C Qo 880 SMALL HOLLOW FAILURE Hell Roaring 1998 HR-8 1 SR/d 0.43 N NA CC 55 D Qo 1080 SMALL IN UNIT FAILURE Hell Roaring 1998 HR-9 1 SR/d 0.25 N NA CC 55 D Qo 840 SMALL IN UNIT FAILURE Hell Roaring 1998 HR-10 1 SR/d 0.15 N NA CC 55 D Qo 720 SMALL IN UNIT FAILURE Owl Creek 1975 OC-1 1 SR/d 0.57 N NA R 85 D Two 2960 Owl Creek 1975 OC-2 1 SR/d 0.18 Y C503 OGF 60 P Two 2240 Owl Creek 1975 OC-3 1 SR/d 0.15 Y C503 OGF 60 P Two 2200 Yarding scar/shallow landslide Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Owl Creek 1975 OC-4 1 SR/d 2.65 Y C509 CC 75 P Two 2000 Owl Creek 1975 OC-5 1 SR/d 0.67 Y C509 R 60 C Two 2280 Owl Creek 1975 OC-6 1 SR/d 0.66 Y C500 OGF 75 P Two 1520 Owl Creek 1975 OC-7 1 SR/d 0.22 Y C500 OGF 85 P Two 1440 Owl Creek 1975 OC-8 1 DBF/d 0.50 Y C516 R 75 C Two 2360 Owl Creek 1975 OC-9 1 SR/d 0.59 Y C518 OGF 60 C Two 2240 Owl Creek 1975 OC-10 1 SR/d 3.23 Y C520 CC 60 C Two 1840 Owl Creek 1975 OC-11 1 SR/d 0.45 Y C521 CC 60 C Two 1880 Yarding damage related Owl Creek 1975 OC-12 1 PDS/p 0.21 Y C520 OGF 60 P Two 1720 Owl Creek 1975 OC-13 1 SR/d 0.31 Y C518 OGF 60 P Two 1560 Owl Creek 1975 OC-14 1 SR/d 0.72 Y C553 CC 75 C Two 1880 Owl Creek 1975 OC-15 1 SR/d 0.16 Y C554 CC 75 C Two 1640 Owl Creek 1975 OC-16 1 SR/d 0.19 Y C554 CC 75 C Two 1720 Sidecast H1820 Owl Creek 1975 OC-17 1 SR/d 0.18 Y C554 R 60 C Two 1880 Sidecast H1820 Owl Creek 1975 OC-18 1 SR/d 0.22 Y C554 R 60 C Two 1760 Sidecast H1820 Owl Creek 1975 OC-19 1 SR/d 0.80 Y C554 R 75 C Two 1840 Sidecast H1820 Owl Creek 1975 OC-20 1 SR/d 0.15 Y C554 R 60 C Two 1760 Sidecast H1820 Owl Creek 1975 OC-21 1 DBF/d 1.77 Y C554 R 75 C Two 1720 Sidecast H1820 Owl Creek 1975 OC-22 1 DBF/d 1.08 Y C556 R 90 C Two 1800 Sidecast H1820 Owl Creek 1975 OC-23 1 DBF/d 1.92 Y C545 R 75 C Two 2600 Owl Creek 1975 OC-24 1 DBF/d 0.47 Y C545 CC 85 C Two 2400 Landing H1750 Owl Creek 1975 OC-25 1 DBF/d 0.68 Y C531 L 85 D Two 2240 Yarding scar Owl Creek 1975 OC-26 1 SR/d 0.14 Y C562 CC 75 C Two 1720 Yarding scar Owl Creek 1975 OC-27 1 SR/d 0.17 Y C562 CC 75 C Two 1520 Yarding scar Owl Creek 1975 OC-28 1 SR/d 0.22 Y C562 CC 65 C Two 1480 Yarding scar Owl Creek 1975 OC-29 1 SR/d 0.21 Y C562 CC 85 C Two 1280 Deep seated stream adjacent Owl Creek 1975 OC-31 1 PDS/p 0.53 Y C558 OGF 65 P Twoc 1080 H1820 spur sidecast Owl Creek 1975 OC-32 1 SR/d 1.38 Y C558 R 85 D Two 1520 H1820 spur sidecast Owl Creek 1975 OC-33 1 SR/d 1.10 Y C561 R 85 D Two 2000 H1820 spur sidecast Owl Creek 1975 OC-34 1 SR/d 1.20 Y C554 R 85 C Two 2080 H1820 spur sidecast Owl Creek 1975 OC-35 1 SR/d 0.67 Y C561 R 85 C Two 2160 H1820 spur sidecast Owl Creek 1975 OC-36 1 SR/d 1.02 Y C561 R 85 C Two 2040 H1820 spur sidecast Owl Creek 1975 OC-37 1 SR/d 1.50 Y C561 R 90 C Two 2080 H1820 spur sidecast Owl Creek 1975 OC-38 1 SR/d 0.96 N NA R 85 D Two 2000 SF Cedar Creek Owl Creek 1975 OC-39 1 DBF/d 0.43 Y C471 CC 85 C Two 2280 Related to pit to east Owl Creek 1975 OC-40 1 SR/d 0.10 Y C468 CC 65 P Qo 560 Related to pit to east Owl Creek 1975 OC-41 1 SR/d 0.28 Y C468 CC 65 P Qo 520 Related to pit to east Owl Creek 1975 OC-42 1 SR/d 0.35 Y C480 R 105 D Two 2560 Sidecast H1800/Landing Owl Creek 1975 OC-43 1 SR/d 0.09 Y C476 CC 65 P Two 1000 Inner gorge failure/balloon yarding Owl Creek 1975 OC-44 1 SR/d 0.09 Y C476 CC 65 P Two 1000 Inner gorge failure/balloon yarding Owl Creek 1975 OC-45 1 SR/d 0.11 Y C476 CC 65 P Two 960 Inner gorge failure/balloon yarding Owl Creek 1975 OC-46 1 SR/d 0.10 Y C476 CC 65 P Two 920 Inner gorge failure/balloon yarding Owl Creek 1975 OC-47 1 SR/d 0.14 Y C476 CC 65 P Two 880 Inner gorge failure/balloon yarding Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Owl Creek 1975 OC-48 1 SR/d 1.35 Y C583 R 85 C Two 1560 H1820 sidecast Owl Creek 1975 OC-49 1 SR/d 0.24 Y C583 CC 85 C Two 1280 Owl Creek 1975 OC-50 1 SR/d 0.25 Y C563 CC 65 P Two 1040 Owl Creek 1975 OC-51 1 SR/d 0.18 Y C563 CC 85 P Two 1160 Owl Creek 1975 OC-52 1 SR/d 1.05 Y C584 R 85 C Two 1400 H1820 sidecast Owl Creek 1975 OC-53 1 DBF/d 0.20 Y C571 R 110 C Twot 2000 H1700 sidecast Owl Creek 1975 OC-54 1 SR/d 0.30 Y C572 R 75 P Twot 1520 H1700 sidecast Owl Creek 1975 OC-55 1 SR/d 0.36 Y C572 R 80 P Twot 1520 H1700 sidecast Owl Creek 1975 OC-56 1 SR/d 0.18 Y C572 R 85 P Twot 1520 H1700 sidecast Owl Creek 1975 OC-57 1 SR/d 0.72 Y C572 R 90 D Twot 1520 H1700 sidecast Owl Creek 1975 OC-58 1 SR/d 0.28 Y C574 R 85 D Two 1320 H1700 sidecast Owl Creek 1975 OC-59 1 SR/d 0.41 Y C574 R 85 D Two 1320 H1700 sidecast Owl Creek 1975 OC-60 1 SR/d 0.13 Y C573 CC 65 C Two 1080 Owl Creek 1975 OC-61 1 SR/d 0.10 Y C573 CC 65 C Two 800 Owl Creek 1975 OC-62 1 SR/d 0.48 Y C593 R 85 C Two 1600 H1800 sidecast Owl Creek 1975 OC-63 1 SR/d 1.22 Y C593 R 85 C Two 1640 H1800 sidecast Owl Creek 1975 OC-64 1 SR/d 0.24 Y C593 OGF 90 P Two 1360 Owl Creek 1975 OC-65 1 SR/d 0.88 Y C597 CC 85 C Two 1560 Owl Creek 1975 OC-66 1 DBF/d 2.56 Y C597 R 85 C Two 1720 H1800 sidecast Owl Creek 1975 OC-70 1 DBF/d 0.74 Y C518 L 75 D Two 2440 H1750 end Owl Creek 1998 OC-1 1 SR/d 0.95 Y C503 R 55 P Two 3040 ROAD SIDECAST FAILURE Owl Creek 1998 OC-2 1 SR/d 0.47 N NA R 55 P Two 3000 ROAD SIDECAST FAILURE Owl Creek 1998 OC-3 1 SR/d 0.81 N NA R 55 P Two 2920 ROAD SIDECAST FAILURE Owl Creek 1998 OC-4 1 SR/d 1.21 Y C501 CC 55 C Two 2440 INNER GORGE ON UPPER N.F. OWL CREEK Owl Creek 1998 OC-5 1 DBF/d 2.63 Y C504 CC 65 C Two 2800 INNER GORGE ON UPPER N.F. OWL CREEK Owl Creek 1998 OC-6 1 DBF/d 4.63 Y C503 CC 55 C Two 2760 CONVERGENT HOLLOW Owl Creek 1998 OC-7 1 DBF/d 0.61 Y C506 CC 65 D Two 2280 ENLARGEMENT OF OLD YARDING SCAR Owl Creek 1998 OC-8 1 DBF/d 2.50 Y C506 CC 65 P Two 2600 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-9 1 DBF/d 5.16 Y C506 CC 110 C Two 2640 ROAD RUNOFF RELATED Owl Creek 1998 OC-10 1 DBF/d 3.45 Y C504 R 75 C Two 2800 SPUR SIDECAST FAILURE Owl Creek 1998 OC-11 1 DBF/d 0.65 Y C507 CC 75 C Two 2880 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-12 1 DBF/d 0.75 Y C507 CC 85 C Two 2720 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-13 1 DBF/d 0.49 Y C507 CC 85 C Two 2320 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-14 1 DBF/d 0.21 Y C507 CC 85 C Two 2280 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-15 1 SR/d 0.27 Y C507 CC 85 C Two 2320 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-16 1 DBF/d 0.71 Y C507 CC 85 C Two 2520 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-17 1 DBF/d 0.53 Y C510 CC 85 C Two 2640 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-18 1 DBF/d 5.07 Y C510 CC 75 C Two 2720 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-19 1 DBF/d 2.15 Y C509 L 75 P Two 1640 SPUR SIDECAST LANDING FAILURE Owl Creek 1998 OC-20 1 DBF/d 1.00 Y C509 CC 65 P Two 2120 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-21 1 DBF/d 1.76 Y C509 CC 75 C Two 1800 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-22 1 DBF/d 1.10 Y C513 CC 85 C Two 2840 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-23 1 DBF/d 0.48 Y C513 CC 75 C Two 2480 HOLLOW AT CHANNEL HEAD Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Owl Creek 1998 OC-24 1 DBF/d 2.08 Y C513 CC 85 C Two 2360 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-25 1 LPDS/p 11.32 Y C509 CC 55 C Two 2120 SHALLOW RAPID ON OLD DEEP SEATED Owl Creek 1998 OC-26 1 DBF/d 13.77 Y C517 CC 85 C Two 2800 CLASSIC HOLLOW FAILURE Owl Creek 1998 OC-27 1 DBF/d 1.55 Y C517 CC 85 C Two 2480 CLASSIC HOLLOW FAILURE Owl Creek 1998 OC-29 1 DBF/d 1.51 Y C518 CC 65 C Two 2560 CONVERGENT HOLLOW Owl Creek 1998 OC-30 1 DBF/d 11.28 Y C518 CC 65 C Two 2600 CONVERGENT HOLLOW Owl Creek 1998 OC-32 1 DBF/d 5.85 Y C518 CC 85 C Two 2360 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-33 1 DBF/d 0.77 Y C523 CC 75 C Two 2440 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-34 1 DBF/d 1.13 Y C523 CC 85 C Two 1480 HOLLOW AT CHANNEL HEAD Owl Creek 1998 OC-35 1 DBF/d 0.26 Y C518 CC 85 P Two 1640 SMALL HOLLOW ON PLANAR RIDGE FACE Owl Creek 1998 OC-36 1 DBF/d 0.74 Y C521 CC 75 C Two 2600 CHANNEL HEAD HOLLOW Owl Creek 1998 OC-37 1 DBF/d 1.21 Y C521 CC 65 C Two 2480 CHANNEL HEAD HOLLOW Owl Creek 1998 OC-38 1 DBF/d 4.34 Y C521 CC 75 C Two 2480 CHANNEL HEAD HOLLOW Owl Creek 1998 OC-39 1 DBF/d 0.77 Y C521 CC 55 C Two 1840 INNER GORGE FAILURE Owl Creek 1998 OC-40 1 DBF/d 4.87 Y C523 CC 75 C Two 2200 HOLLOW FAILURE 200 FT BELOW ROAD Owl Creek 1998 OC-41 1 SR/d 0.53 N NA CC 85 P Two 1560 SHALLOW RAPID LANDSLIDES ON DEEP SEATED Owl Creek 1998 OC-42 1 SR/d 0.46 N NA CC 115 P Two 1560 SHALLOW RAPID LANDSLIDES ON DEEP SEATED Owl Creek 1998 OC-43 1 SR/d 1.04 Y C555 CC 85 C Two 1480 HEADWALL FAILURE Owl Creek 1998 OC-44 1 DBF/d 16.64 Y C526 CC 75 C Two 2120 LARGE DEBRIS FLOW Owl Creek 1998 OC-45 1 DBF/d 2.83 Y C536 CC 55 C Two 2200 HOLLOW FAILURE IN CHANNEL Owl Creek 1998 OC-46 1 DBF/d 4.18 Y C536 CC 115 P Two 2600 HOLLOW FAILURE Owl Creek 1998 OC-47 1 SR/d 1.96 Y C542 CC 55 C Two 2240 INNER GORGE FAILURES Owl Creek 1998 OC-48 1 SR/d 1.77 Y C542 CC 55 C Two 2280 INNER GORGE FAILURES Owl Creek 1998 OC-49 1 SR/d 2.63 Y C542 CC 65 C Two 1960 INNER GORGE FAILURES Owl Creek 1998 OC-51 1 DBF/d 10.32 Y C531 CC 55 C Two 1440 CHANNEL ADJACENT HOLLOW FAILURE Owl Creek 1998 OC-52 1 SR/d 1.62 Y C548 L 85 C Two 2320 ROA D DRAINAGE ON SIDECAST Owl Creek 1998 OC-53 1 SR/d 0.43 Y C565 CC 85 P Two 1400 SMALL INNER GORGE FAILURE Owl Creek 1998 OC-54 1 SR/d 0.22 Y C559 CC 55 P Two 1240 SMALL INNER GORGE FAILURE Owl Creek 1998 OC-55 1 SR/d 0.50 Y C559 CC 75 P Two 1200 SMALL INNER GORGE FAILURE Owl Creek 1998 OC-56 1 SR/d 0.39 Y C559 CC 85 P Two 1240 SMALL INNER GORGE FAILURE Owl Creek 1998 OC-57 1 SR/d 1.72 Y C558 R 85 C Two 1800 ROAD CUTSLOPE FAILURE AT STREAM CROSSING Owl Creek 1998 OC-58 1 SR/d 2.34 Y C583 CC 85 C Two 1960 IN UNIT FAILURE ABOVE ROAD CROSSING Owl Creek 1998 OC-59 1 SR/d 0.23 N NA CC 70 D Two 1040 IN UNIT FAILURE Owl Creek 1998 OC-60 1 SR/d 0.41 N NA CC 70 D Two 1120 IN UNIT FAILURE Owl Creek 1998 OC-61 1 DBF/d 10.83 Y C568 R 65 C Two 2120 CHANNEL HEAD BELOW ROAD Owl Creek 1998 OC-62 1 SR/d 2.09 Y C568 CC 55 P Two 1240 INNER GORGE Owl Creek 1998 OC-63 1 SR/d 6.09 Y C498 CC 55 P Two 920 INNER GORGE ON OWL CREEK Owl Creek 1998 OC-64 1 DBF/d 9.28 Y C571 R 85 C Two 1960 CHANNEL HEAD BELOW ROAD Owl Creek 1998 OC-64b 1 SR/d 0.36 Y C593 CC 85 P Two 1240 INNER GORGE Owl Creek 1998 OC-65 1 DBF/d 2.32 Y C571 R 85 C Two 1640 CHANNEL HEAD BELOW ROAD Owl Creek 1998 OC-65b 1 SR/d 0.54 Y C599 CC 85 P Two 1720 INNER GORGE Owl Creek 1998 OC-66 1 DBF/d 5.16 Y C572 R 85 C Two 1920 BIG DEBRIS FLOW INTO OWL CREEK Owl Creek 1998 OC-66b 1 DBF/d 1.16 Y C611 CC 85 C Two 1960 CHANNEL HEAD Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Owl Creek 1998 OC-67 1 DBF/d 25.57 Y C601 CC 75 C Two 1920 CHANNEL HEAD FAILURE INTO OWL CREEK Owl Creek 1998 OC-68 1 DBF/d 0.23 Y C598 CC 85 P Two 1440 INNER GORGE FAILURE Owl Creek 1998 OC-69 1 SR/d 0.54 Y C598 CC 85 P Two 1280 INNER GORGE FAILURE Owl Creek 1998 OC-70 1 SR/d 0.13 Y C598 CC 85 P Two 1160 INNER GORGE FAILURE Owl Creek 1998 OC-71 1 SR/d 0.21 Y C598 CC 85 P Two 1200 INNER GORGE FAILURE Owl Creek 1998 OC-72 1 DBF/d 7.58 Y C482 R 55 C Two 1800 HOLLOW FAILURE BELOW ROAD, DBF INTO HOH. Owl Creek 1998 OC-73 1 DBF/d 21.25 Y C480 R 85 C Two 2400 HOLLOW FAILURE BELOW ROAD Owl Creek 1998 OC-74 1 DBF/d 3.63 Y C480 R 95 C Two 2520 HOLLOW FAILURE BELOW ROAD Owl Creek 1998 OC-75 1 DBF/d 2.83 Y C480 CC 95 C Two 2280 HOLLOW FAILURE BELOW ROAD Owl Creek 1998 OC-76 1 DBF/d 1.61 Y C480 CC 95 C Two 2280 HOLLOW FAILURE BELOW ROAD Owl Creek 1998 OC-77 1 DBF/d 3.36 Y C480 CC 75 C Two 1920 HOLLOW FAILURE Owl Creek 1998 OC-78 1 DBF/d 1.31 Y C480 CC 115 C Two 1720 HOLLOW FAILURE Owl Creek 1998 OC-79 1 DBF/d 0.20 Y C480 CC 115 C Two 1160 HOLLOW FAILURE Owl Creek 1998 OC-80 1 DBF/d 0.92 Y C471 CC 85 C Two 2040 TRIB TO SF CEDAR CREEK Owl Creek 1998 OC-81 1 DBF/d 2.92 Y C471 R 65 C Two 2600 FILLSLOPE FAILURE IN HOLLOW South Fork 1975 SF-7 1 SR/DF 0.29 Y C441 R 85 C Ttr 2740 Road Failure H1875 South Fork 1975 SF-8 1 SR/d 0.17 Y C441 CC 75 C Ttr 1000 Split Creek South Fork 1975 SF-9 1 SR/d 0.16 Y C437 CC 75 C Ttr 1000 Split Creek South Fork 1975 SF-10 1 SR/d 0.31 Y C437 CC 75 C Ttr 1000 Split Creek South Fork 1975 SF-11 1 SR/d 0.18 Y C437 CC 75 C Ttr 920 Split Creek South Fork 1975 SF-12 1 SR/d 0.18 Y C437 CC 75 C Ttr 960 Split Creek South Fork 1975 SF-13 1 SR/d 0.28 Y C437 CC 75 C Ttr 800 Split Creek South Fork 1975 SF-14 1 SR/d 0.92 Y C407 CC 75 C Ttr 2200 Boundary Creek South Fork 1975 SF-15 1 SR/d 0.63 Y C407 CC 85 C Ttr 1480 South Fork 1975 SF-16 1 SR/d 0.67 Y C407 CC 85 C Ttr 1500 South Fork 1975 SF-17 1 SR/d 1.35 Y C407 CC 75 C Ttr 1480 South Fork 1975 SF-18 1 SR/d 0.23 Y C407 R 75 D Ttr 1380 Landing Failure/Road Drainage South Fork 1975 SF-19 1 SR/d 0.26 Y C407 CC 75 C Ttr 1340 South Fork 1998 SF-1 1 SR/d 0.67 Y C207 CC 85 C Two 3480 HOLLOW FAILURE South Fork 1998 SF-2 1 SR/d 0.52 Y C207 CC 75 C Two 3200 DEBRIS FLOW South Fork 1998 SF-3 1 SR/d 2.14 Y C207 CC 105 P Two 2120 INNER GORGE South Fork 1998 SF-4 1 SR/d 0.37 Y C207 CC 75 P Two 1480 INNER GORGE South Fork 1998 SF-5 1 SR/d 0.37 Y C205 CC 85 C Two 1360 South Fork 1998 SF-6 1 SR/d 0.91 Y C207 CC 95 C Two 2040 HOLLOW South Fork 1998 SF-7 1 DBF/d 1.15 Y C203 CC 95 C Two 2960 HOLLOW South Fork 1998 SF-8 1 DBF/d 0.33 Y C203 CC 85 C Two 2400 South Fork 1998 SF-9 1 SR/d 0.67 Y C203 CC 95 P Two 1840 INNER GORGE South Fork 1998 SF-10 1 DBF/d 1.03 Y C203 CC 95 C Two 2160 HOLLOW South Fork 1998 SF-11 1 SR/d 0.72 Y C198 CC 95 C Two 1720 HOLLOW South Fork 1998 SF-12 1 SR/d 1.17 Y C193 R 85 C Two 2120 ROAD FILLSLOPE FAILURE IN HOLLOW South Fork 1998 SF-13 1 SR/d 0.79 Y C193 CC 75 P Two 1480 INNER GORGE South Fork 1998 SF-14 1 SR/d 0.33 Y C190 CC 75 C Two 1560 INNER GORGE South Fork 1998 SF-15 1 SR/d 0.37 Y C190 R 75 C Qo 1600 ROAD FILLSLOPE FAILURE IN HOLLOW Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module South Fork 1998 SF- 23 1 SR/d 0.21 N NA R 55 P Two 560 ROAD FILLSLOPE FAILURE IN TERRACE South Fork 1998 SF- 24 1 SR/d 0.38 Y C406 CC 55 C Two 1840 HOLLOW FAILURE South Fork 1998 SF- 25 1 SR/d 0.27 Y C406 CC 75 C Two 1600 HOLLOW FAILURE South Fork 1998 SF- 26 1 SR/d 0.48 Y C406 CC 95 C Two 1480 HOLLOW FAILURE South Fork 1998 SF- 27 1 SR/d 2.94 Y C409 R 85 P Two 1920 ROAD FILLSLOPE FAILURE South Fork 1998 SF- 28 1 LPD/p 5.33 Y C410 CC 85 C Two 2200 VALLEY HEADWALL South Fork 1998 SF- 29 1 SR/d 2.77 Y C413 CC 85 C Two 2400 HOLLOW FAILURE South Fork 1998 SF- 30 1 SR/d 0.19 Y C413 CC 95 C Two 2400 HOLLOW FAILURE South Fork 1998 SF- 31 1 SR/d 1.58 Y C413 CC 95 C Two 2120 HOLLOW FAILURE South Fork 1998 SF- 32 1 SR/d 1.55 Y C420 CC/R 85 C Two 2400 ROAD RELATED HOLLOW FAILURE South Fork 1998 SF- 33 1 DBF/d 1.13 Y C420 CC 95 C Two 2240 LARGE DEBRIS FLOW South Fork 1998 SF- 34 1 SR/d 1.16 Y C418 CC 95 C Two 2200 HOLLOW FAILURE South Fork 1998 SF- 35 1 DBF/d 0.69 Y C427 CC 85 P Two 2600 HOLLOW FAILURE ON DIVERGENT RIDGE South Fork 1998 SF- 36 1 DBF/d 0.71 Y C427 CC 85 P Two 2640 HOLLOW FAILURE ON DIVERGENT RIDGE South Fork 1998 SF- 37 1 DBF/d 1.02 Y C429 CC 95 C Two 2200 HOLLOW FAILURE South Fork 1998 SF- 38 1 DBF/d 0.28 Y C427 CC 75 C Two 2240 HOLLOW FAILURE South Fork 1998 SF- 39 1 SR/d 0.39 Y C427 CC 95 C Two 1680 INNER GORGE South Fork 1998 SF- 40 1 SR/d 0.37 Y C427 CC 105 C Two 1520 TRIB TO MAINSTEM, INNER GORGE FAILURE South Fork 1998 SF- 41 1 DBF/d 0.41 Y C429 L 75 D Two 2840 LANDING FAILURE THROUGH CLEARCUT South Fork 1998 SF- 42 1 DBF/d 0.16 Y C429 CC 85 C Two 2320 IN UNIT FAILURE South Fork 1998 SF- 43 1 DBF/d 0.11 Y C429 CC 85 C Two 2280 IN UNIT FAILURE South Fork 1998 SF- 44 1 DBF/d 0.18 Y C429 CC 95 C Two 2600 IN UNIT FAILURE South Fork 1998 SF- 45 1 SR/d 0.75 Y C429 CC 85 C Two 2080 IN UNIT FAILURE South Fork 1998 SF- 46 1 SR/d 0.35 Y C429 CC 65 C Two 1720 IN UNIT FAILURE South Fork 1998 SF- 47 1 DBF/d 0.40 Y C429 CC 85 C Two 1720 TR JUNCTION HOLLOW FAILURE South Fork 1998 SF- 48 1 DBF/d 0.59 Y C429 CC 75 C Two 1920 IN UNIT FAILURE South Fork 1998 SF- 49 1 DBF/d 0.56 Y C429 CC 75 C Two 2040 IN UNIT FAILURE South Fork 1998 SF- 50 1 DBF/d 0.28 Y C431 CC/R 75 C Two 2200 ROAD RUNOFF RELATED South Fork 1998 SF- 51 1 DBF/d 0.14 Y C431 CC 75 C Two 1760 INNER GORGE South Fork 1998 SF- 52 1 DBF/d 0.16 Y C431 CC 85 C Two 1600 INNER GORGE South Fork 1998 SF- 53 1 DBF/d 1.16 Y C431 CC 95 D Two 1640 IN UNIT FAILURE South Fork 1998 SF- 54 1 DBF/d 1.63 Y C435 CC 75 C Two 1880 CLASSIC HOLLOW FAILURE South Fork 1998 SF- 55 1 SR/d 0.32 Y C435 CC 95 C Two 1760 CLASSIC HOLLOW FAILURE South Fork 1998 SF- 56 1 DBF/d 1.61 Y C441 CC 85 C Two 2440 ROAD RUNOFF RELATED South Fork 1998 SF- 57 1 DBF/d 1.54 Y C441 CC 75 C Two 2360 HOLLOW FAILURE South Fork 1998 SF- 58 1 DBF/d 1.20 Y C442 CC 85 C Two 2040 HOLLOW FAILURE South Fork 1998 SF- 59 1 DBF/d 0.96 Y C442 CC 75 C Two 1880 SMALL TRIB E.F. SPLIT CREEK South Fork 1998 SF- 60 1 SR/d 4.12 Y C442 CC 85 C Two 2280 SMALL TRIB E.F. SPLIT CREEK South Fork 1998 SF- 61 1 DBF/d 0.38 Y C442 CC 85 C Two 1760 SMALL TRIB E.F. SPLIT CREEK South Fork 1998 SF- 62 1 SR/d 0.25 Y C438 CC 85 D Two 1440 INNER GORGE E.F. SPLIT CREEK South Fork 1998 SF- 63 1 SPDS 2.69 Y C438 CC 65 C Two 1280 INNER GORGE E.F. SPLIT CREEK South Fork 1998 SF- 64 1 SR/d 0.24 Y C438 CC 85 C Two 1200 INNER GORGE E.F. SPLIT CREEK South Fork 1998 SF- 65 1 SPDS 2.96 Y C444 CC 85 C Two 1760 WEST FORK SPLIT CREEK Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module South Fork 1998 SF- 66 1 SPDS 2.56 Y C446 CC 95 C Two 1680 WEST FORK SPLIT CREEK South Fork 1998 SF- 67 1 DBF/d 0.15 Y C445 CC 55 C Two 2360 WEST FORK SPLIT CREEK South Fork 1998 SF- 68 1 SR/d 1.38 Y C446 CC 75 C Two 2200 WEST FORK SPLIT CREEK South Fork 1998 SF- 69 1 SR/d 0.25 N NA L 95 D Two 2040 LANDING FAILURE THROUGH CLEARCUT South Fork 1998 SF- 70 1 LPDS/p 16.33 Y C447 CC 85 P Two 2080 McQUARRY CREEK South Fork 1998 SF- 71 1 DBF/d 0.24 Y C449 CC 75 D Two 1960 TRIB TO McQUARRY CREEK South Fork 1998 SF- 72 1 DBF/d 0.14 Y C449 CC 95 D Two 1720 TRIB TO McQUARRY CREEK South Fork 1998 SF- 73 1 SR/d 0.61 Y C447 CC 95 P Two 1400 INNER GORGE ON McQUARRY CREEK South Fork 1998 SF- 74 1 SR/d 0.67 Y C450 CC 95 P Two 1160 INNER GORGE ON McQUARRY CREEK South Fork 1998 SF- 75 1 SR/d 0.49 Y C450 CC 95 P Two 1480 INNER GORGE ON McQUARRY CREEK South Fork 1998 SF- 76 1 SR/d 2.31 Y C450 CC 95 P Two 1800 INNER GORGE ON McQUARRY CREEK South Fork 1998 SF-76B 1 DBF/d 1.43 Y C451 CC 65 C Two 1600 South Fork 1998 SF- 77 1 SR/d 4.30 Y C450 CC 115 P Two 2120 TRIB TO McQUARRY CREEK South Fork 1998 SF-77B 1 DBF/d 2.15 Y C451 CC 115 C Two 1800 South Fork 1998 SF- 78 1 SR/d 0.29 Y C450 CC 115 P Two 2160 TRIB TO McQUARRY CREEK South Fork 1998 SF-78B 1 DBF/d 1.43 N NA CC 55 D Two 1420 South Fork 1998 SF- 79 1 DBF/d 3.06 Y C450 CC 85 P Two 2360 TRIB TO McQUARRY CREEK South Fork 1998 SF-79B 1 DBF/d 2.33 Y C453 CC 85 C Two 1800 South Fork 1998 SF- 80 1 DBF/d 7.23 Y C450 CC 75 C Two 2280 TRIB TO McQUARRY CREEK South Fork 1998 SF-80B 1 DBF/d 2.86 Y C453 CC 85 C Two 2280 South Fork 1998 SF- 81 1 DBF/d 2.49 Y C453 CC 115 C Two 2240 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 82 1 SR/d 1.15 Y C453 CC 65 C Two 1880 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 83 1 SR/d 2.37 Y C453 CC 65 C Two 2200 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 84 1 DBF/d 1.87 Y C453 CC 65 C Two 2400 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 85 1 DBF/d 0.69 Y C453 CC 65 C Two 2360 HEADWATER TRIB OF VIRGINIA CREEK South Fork 1998 SF- 86 1 DBF/d 2.88 Y C453 CC 95 C Two 2480 HEADWATER TRIB OF VIRGINIA CREEK South Fork 1998 SF- 87 1 SR/d 1.87 N NA CC 75 C Two 2400 HEADWATER TRIB OF VIRGINIA CREEK South Fork 1998 SF- 88 1 SR/d 1.78 Y C453 CC 85 C Two 2000 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 89 1 SR/d 2.58 Y C454 CC 85 C Two 2360 TRIB TO VIRGINIA CREEK South Fork 1998 SF- 90 1 DBF/d 0.45 Y C461 CC 126 D Two 2000 TRIB WEST OF VIRGINIA CREEK South Fork 1998 SF- 91 1 DBF/d 9.59 Y C461 CC 85 C Two 2080 TRIB WEST OF VIRGINIA CREEK South Fork 1998 SF- 92 1 DBF/d 3.37 Y C461 R 85 D Two 2560 ROAD SIDECAST ON NOSE, BIG DEBRIS FLOW South Fork 1998 SF- 93 1 SR/d 0.32 Y C461 CC 85 C Two 1240 SHORT STEEP TRIB Spruce 1939 SC-1 1 SR/1 0.63 Y C148 OGF 80 p Tur 1560 Inner gorge topography Spruce 1939 SC-2 1 SR/1 0.92 Y C151 OGF 95 c Tur 1800 Inner gorge topography Spruce 1939 SC-3 1 SR/1 0.46 Y C151 OGF 100 c Tur 1800 Inner gorge headwall Spruce 1939 SC-4 1 SR/1 0.25 N NA OGF 80 d Tur 1680 Divergent Nose Spruce 1939 SC-5 1 SR/1 0.24 Y C148 OGF 110 c Tur 1240 Head of type 5 channel Spruce 1939 SC-6 1 SR/1 0.35 Y C147 OGF 100 p Tur 1120 Steep planar inner gorge slope Spruce 1939 SC-7 1 SR/1 0.43 N NA OGF 75 d Tur 1120 Divergent Nose Spruce 1939 SC-8 1 SR/1 0.34 N NA OGF 75 d Tur 1080 Divergent Nose Spruce 1939 SC-9 1 SR/1 2.81 Y C179 OGF 90 c Tur 2480 Headwall type 5 Spruce 1939 SC-10 1 SR/1 2.88 Y C179 OGF 90 c Tur 2480 Headwall type 5 Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Spruce 1939 SC-11 1 LPD/3 29.79 Y C178 OGF 85 c Tur 2480 Deep Seated failure turning into Debris Flow Spruce 1975 SC-1 1 DSS/d 2.87 N NA OGF 65 P Qta 680 Glacial Terrace above wetland Spruce 1975 SC-2 1 DSP/d 4.94 Y C179 OGF 85 C Ttr 2540 Large deep seated Spruce 1975 SC-3 1 SR/d 0.72 Y C179 OGF 90 C Ttr 2500 channel head Spruce 1975 SC-4 1 SR/d 0.34 Y C179 OGF 90 C Ttr 2640 channel head Spruce 1975 SC-5 1 SR/d 1.15 Y C179 OGF 75 C Ttr 2000 TributaryJunction Spruce 1975 SC-6 1 SR/d 0.88 N NA R 85 P Ttr 2241 H3900 Spruce 1975 SC-7 1 SR/d 0.52 N NA R 85 P Ttr 1080 H3900 Spruce 1975 SC-8 1 SR/d 0.57 N NA R 85 P Ttr 1080 H3900 Spruce 1975 SC-9 1 DBF/d 1.77 Y C174 R 85 C Ttr 1100 H3900 Spruce 1975 SC-10 1 SR/d 3.23 Y C174 R 90 P Ttr 2120 H3960 Spruce 1975 SC-11 1 SR/d 0.86 Y C168 R 85 C Ttr 1800 H3900 Spruce 1975 SC-12 1 SR/d 0.29 Y C162 R 85 D Ttr 1860 H3900 Sidecast Spruce 1975 SC-13 1 SR/d 0.23 Y C162 R 90 C Ttr 2200 H3900 Stream crossing Spruce 1975 SC-14 1 SR/d 0.35 Y C161 R 90 C Ttr 2160 H3900 Sidecast Failure Spruce 1975 SC-15 1 SR/d 0.29 Y C161 R 90 C Ttr 2280 H3900 Sidecast Failure Spruce 1975 SC-16 1 SR/d 0.27 Y C161 CC 85 C Ttr 2120 In unit failure in hollow Spruce 1975 SC-17 1 SR/d 0.42 Y C161 CC 90 C Ttr 1840 In unit failure in hollow Spruce 1975 SC-18 1 SR/d 0.33 Y C157 CC 90 C Ttr 1760 In unit failure in hollow Spruce 1975 SC-19 1 SR/d 0.12 Y C163 R 95 P Ttr 2320 H3900 Sidecast Failure Spruce 1975 SC-20 1 DBF/d 2.56 Y C167 R 85 P Ttr 2000 H3900 Spur Sidecast Failure Spruce 1975 SC-21 1 SR/d 1.11 N NA CC 55 D Ttr 1640 In unit failure (yarding) Spruce 1975 SC-22 1 DBF/d 0.25 Y C157 CC 55 C Ttr 1560 stream channel initiation Spruce 1975 SC-23 1 SR/d 1.18 Y C157 OGF 85 P Ttr 1640 Stream adjacent slope failure Spruce 1975 SC-24 1 SR/d 0.82 Y C154 R 65 C Ttr 2200 H3900 Sidecast Failure Spruce 1975 SC-25 1 DSS/d 0.72 Y C162 OGF 95 C Ttr 2520 channel headwall deep seated Spruce 1975 SC-26 1 SR/d 0.37 Y C163 OGF 65 C Ttr 1720 Bank failure Spruce 1975 SC-27 1 SR/d 0.80 Y C157 OGF 65 C Ttr 1600 Bank failure Spruce 1975 SC-28 1 DBF/d 0.87 Y C160 OGF 95 C Ttr 1880 Headwall zero order channel Spruce 1975 SC-29 1 SR/d 0.28 Y C149 OGF 85 C Ttr 1600 Inner gorge Spruce 1975 SC-30 1 SR/d 1.22 Y C148 OGF 85 C Ttr 1800 Inner gorge Spruce 1975 SC-31 1 SR/d 1.43 Y C150 OGF 90 C Ttr 2120 Inner gorge Spruce 1975 SC-32 1 SR/d 0.77 Y C150 OGF 95 C Ttr 2200 Headwall Spruce 1975 SC-33 1 DBF/d 1.54 Y C150 OGF 110 C Ttr 2400 Headwall Spruce 1975 SC-34 1 DBF/d 1.47 Y C148 OGF 90 C Ttr 1800 Headwall Spruce 1998 SC-1 1 SR/d 4.82 Y C179 SG 85 C Two 2760 FRESH FAILURES ON OLD SCARS Spruce 1998 SC-2 1 SR/d 11.48 Y C179 SG 75 C Two 2600 FRESH FAILURES ON OLD SCARS Spruce 1998 SC-3 1 SR/d 0.71 Y C179 SG 115 C Two 2160 FRESH FAILURES ON OLD SCARS Spruce 1998 SC-4 1 DBF/d 4.09 Y C178 CC 115 C Two 1520 SHALLOW RAPID IN TRIB, DEBRIS FLOW IN C178 Spruce 1998 SC-5 1 DBF/d 4.91 Y C179 CC 75 C Two 2240 SHALLOW RAPID IN TRIB, DEBRIS FLOW IN C178 Spruce 1998 SC-6 1 DBF/d 2.22 Y C179 CC 75 C Two 2280 SHALLOW RAPID IN TRIB, DEBRIS FLOW IN C178 Spruce 1998 SC-7 1 DBF/d 2.57 Y C174 CC 75 C Two 2640 CONVERGENT HOLLOW BELOW ROAD Spruce 1998 SC-8 1 DBF/d 5.92 Y C174 R 115 C Two 2520 ROAD SIDECAST FAILURE Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Spruce 1998 SC-9 1 SR/d 2.14 Y C174 R 115 C Two 2320 ROAD SIDECAST FAILURE Spruce 1998 SC-10 1 DBF/d 0.32 Y C161 CC 75 C Two 3120 HEADWALL FAILURE Spruce 1998 SC-11 1 DBF/d 0.25 Y C161 CC 75 C Two 2960 HEADWALL FAILURE Spruce 1998 SC-12 1 DBF/d 0.72 Y C161 CC 75 C Two 2840 HEADWALL FAILURE Spruce 1998 SC-13 1 SR/d 0.36 Y C161 CC/R 75 C Two 2520 SMALL INNER GORGE FAILURE Spruce 1998 SC-14 1 SR/d 1.55 Y C161 CC 85 P Two 2000 INNER GORGE FAILURE Spruce 1998 SC-15 1 SR/d 3.55 Y C157 CC 85 D Two 1920 INNER GORGE COMPLEX ON CANYON CREEK Spruce 1998 SC-16 1 SR/d 1.42 Y C157 R 85 C Two 2120 ROAD SIDECAST FAILURE Spruce 1998 SC-17 1 SR/d 0.52 Y C157 CC 85 P Two 2000 INNER GORGE FAILURE TRIGGERED BY SC Spruce 1998 SC-18 1 SR/d 1.85 Y C157 CC 115 D Two 1560 INNER GORGE COMPLEX ON CANYON CREEK Spruce 1998 SC-19 1 DBF/d 0.34 Y C162 SGF 85 C Two 2240 HEADWALL FAILURE W.F. CANYON CREEK Spruce 1998 SC-20 1 DBF/d 1.45 Y C162 SGF 85 C Two 2240 HEADWALL FAILURE W.F. CANYON CREEK Spruce 1998 SC-21 1 DBF/d 2.37 Y C162 R 85 D Two 2040 EXPANDED FAILURE FROM PREVIOUS SIDECAST Spruce 1998 SC-22 1 DBF/d 1.84 Y C162 OGF 85 C Two 2680 HEADWALL FAILURE W.F. CANYON CREEK Spruce 1998 SC-23 1 DBF/d 4.33 Y C162 OGF 85 C Two 2760 HEADWALL FAILURE W.F. CANYON CREEK Spruce 1998 SC-24 1 SR/d 4.88 Y C157 CC 85 C Two 1280 INNER GORGE COMPLEX INITIATED BY SC Spruce 1998 SC-25 1 SR/d 1.97 Y C168 CC 75 C Two 1520 HOLLOW ON GLACIAL/TWo CONTACT Spruce 1998 SC-26 1 SR/d 0.29 Y C149 R 115 P Two 1480 ROAD SIDECAST FAILURE Spruce 1998 SC-27 1 DBF/d 14.18 Y C149 CC 115 C Two 2080 CONVERGENT HOLLOW BIG DEBRIS FLOW Spruce 1998 SC-28 1 DBF/d 0.34 Y C149 CC 75 C Two 2640 CONVERGENT HOLLOW BIG DEBRIS FLOW Spruce 1998 SC-29 1 DBF/d 0.61 Y C149 CC 85 C Two 2040 CONVERGENT HOLLOW BIG DEBRIS FLOW Spruce 1998 SC-30 1 DBF/d 2.80 Y C150 CC 75 C Two 2640 HOLLOW AT CHANNEL HEAD Spruce 1998 SC-31 1 DBF/d 1.91 Y C150 CC/R 85 C Two 2560 ROAD DRAINAGE ON FILLSLOPE Spruce 1998 SC-32 1 DBF/d 0.25 Y C150 CC 115 C Two 2400 HOLLOW AT CHANNEL HEAD Spruce 1998 SC-33 1 SR/d 0.73 Y C151 CC 115 D Two 1880 INNER GORGE FAILURES INITIATED BY SC Spruce 1998 SC-34 1 DBF/d 1.41 Y C151 CC 85 C Two 2040 HOLLOW AT CHANNEL HEAD Tower Creek 1939 TC-1 1 SR/2 1.40 Y C126 OGF 70 c Tur 1760 Inner gorge of Tower Creek M.S. Tower Creek 1939 TC-2 1 LPD/2 2.19 Y C122 OGF 80 c Tur 1480 Inner gorge of trib. to Tower Creek Tower Creek 1939 TC-3 1 SR/1 1.92 Y C120 OGF 70 c Tur 2080 Headwall failure Tower Creek 1939 TC-4 1 SR/1 1.85 Y C113 OGF 90 c Tur 1120 Headwall failure Tower Creek 1975 TC-1 1 SR/d 0.78 Y C112 OGF 85 P Two 960 Lindner Creek Tower Creek 1998 TC-1 1 SR/d 2.31 Y C142 CC 65 P Qo 1120 INNER GORGE OF DISMAL CREEK Tower Creek 1998 TC-2 1 DBF/d 4.23 Y C142 CC 115 C Two 1720 HEADWALL FAILURE Tower Creek 1998 TC-3 1 SR/d 0.13 N NA CC 85 C Two 1400 IN UNIT HOLLOW FAILURE Tower Creek 1998 TC-5 1 DBF/d 1.10 Y C133 R 85 P Two 1400 SIDECAST FAILURE Tower Creek 1998 TC-6 1 DBF/d 0.84 Y C126 CC 85 C Two 1800 HOLLOW CHANNEL HEAD FAILURE Tower Creek 1998 TC-7 1 DBF/d 0.91 Y C126 CC 75 C Two 1800 HOLLOW AT TRIBUTARY JUNCTION Tower Creek 1998 TC-8 1 DBF/d 0.73 Y C121 CC 115 C Two 2600 TRIBUTARY HEADWALL HOLLOW FAILURE Tower Creek 1998 TC-9 1 DBF/d 0.21 Y C121 CC 85 C Two 2200 TRIBUTARY HEADWALL HOLLOW FAILURE Tower Creek 1998 TC-10 1 SR/d 0.51 Y C121 CC 55 C Two 1720 INNER GORGE Tower Creek 1998 TC-11 1 SR/d 0.40 Y C122 CC 85 C Two 1520 STEEP TRIB WEST FORK TOWER CREEK Tower Creek 1998 TC-12 1 SR/d 0.50 Y C122 CC 85 C Two 1160 INNER GORGE FAILURE SMALL Tower Creek 1998 TC-13 1 SR/d 0.22 Y C122 CC 55 C Two 1000 INNER GORGE FAILURE SMALL Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Tower Creek 1998 TC-14 1 SR/d 0.33 Y C119 CC 55 P Two 920 INNER GORGE FAILURE SMALL Tower Creek 1998 TC-15 1 SR/d 0.62 Y C120 CC 75 C Two 2000 CHANNEL HEAD HOLLOW FAILURE Tower Creek 1998 TC-16 1 SR/d 0.48 Y C120 CC 75 C Two 1880 CHANNEL HEAD HOLLOW FAILURE Tower Creek 1998 TC-17 1 SR/d 0.41 Y C120 CC 75 P Two 1480 INNER GORGE FAILURE Tower Creek 1998 TC-18 1 DBF/d 0.50 Y C120 CC 85 C Two 1960 CHANNEL HEAD HOLLOW FAILURE Tower Creek 1998 TC-19 1 SR/d 0.42 Y C119 CC 55 C Two 1360 INNER GORGE Tower Creek 1998 TC-20 1 SR/d 0.43 Y C119 CC 55 C Two 1280 INNER GORGE Tower Creek 1998 TC-23 1 SR/d 0.20 Y C113 CC 65 C Two 1440 SMALL INNER GORGE FAILURE Tower Creek 1998 TC-24 1 SR/d 0.58 Y C113 CC 75 D Two 1320 SMALL HOLLOW FAILURE Tower Creek 1998 TC-25 1 SR/d 0.62 Y C108 CC 85 C Two 1840 SMALL HOLLOW FAILURE NEXT TO CHANNEL Tower Creek 1998 TC-26 1 SR/d 1.74 Y C108 CC 75 C Two 1960 INNER GORGE FAILURE Tower Creek 1998 TC-27 1 SR/d 1.97 Y C108 CC 85 C Two 2000 INNER GORGE FAILURE Tower Creek 1998 TC-28 1 SR/d 0.74 Y C108 CC 65 C Two 1720 INNER GORGE FAILURE Tower Creek 1998 TC-29 1 DBF/d 0.25 Y C104 R 55 P Two 1040 ROAD FILLSLOPE FAILURE TO SMALL DBF Willoughby 1939 WC-1 1 SR/1 0.39 Y C105 OGF 70 c Tur 1480 Inner gorge Willoughby 1939 WC-2 1 SR/1 1.99 Y C105 OGF 70 c Tur 1760 Inner gorge Willoughby 1939 WC-3 1 SR/1 2.47 Y C105 OGF 90 c Tur 2080 Headwall failure Willoughby 1939 WC-4 1 SR/1 0.56 Y C105 OGF 85 c Tur 1600 Inner gorge Willoughby 1939 WC-5 1 SR/1 2.01 Y C106 OGF 70 c Tur 2000 Headwall failure Willoughby 1939 WC-6 1 SR/1 0.73 Y C106 OGF 70 c Tur 2080 Inner gorge Willoughby 1939 WC-7 1 SR/1 1.17 Y C107 OGF 65 c Tur 2280 Headwall failure Willoughby 1939 WC-8 1 SR/1 0.78 Y C106 OGF 65 d Tur 1840 Divergent slope/inner gorge Willoughby 1939 WC-9 1 SR/1 0.43 Y C107 OGF 100 p Tur 2000 Inner gorge Willoughby 1939 WC-10 1 SSDS/2 2.17 Y C93 OGF 50 c Tur 2080 Convergent inner gorge slope Willoughby 1939 WC-11 1 SSDS/2 0.36 Y C93 OGF 100 p Tur 2200 Inner gorge Willoughby 1939 WC-12 1 SSDS/1 0.22 Y C93 OGF 110 p Tur 2200 Inner gorge Willoughby 1939 WC-13 1 SR/1 0.90 Y C92 OGF 110 d Tur 1960 Channel head hollow failure Willoughby 1939 WC-14 1 SSDS/1 0.93 Y C92 OGF 100 p Tur 2000 Convergent Willoughby 1939 WC-15 1 SSDS/1 2.56 Y C90 OGF 90 c Tur 2200 Channel head Complex Willoughby 1939 WC-16 1 SR/1 0.60 Y C90 OGF 95 c Tur 2040 Inner gorge Willoughby 1939 WC-17 1 SR/1 0.57 Y C90 OGF 90 c Tur 1880 Channel head hollow failure Willoughby 1939 WC-18 1 SR/1 1.02 Y C84 OGF 106 c Tur 1480 Channel head hollow failure Willoughby 1939 WC-19 1 SR/1 1.16 Y C82 OGF 93 c Tur 1000 Channel head hollow failure Willoughby 1939 WC-20 1 SSDS/2 0.52 Y C84 OGF 100 p Tur 960 Inner gorge bank failure Willoughby 1939 WC-21 1 SR/1 0.30 Y C84 OGF 100 d Tur 1400 Inner gorge bank failure Willoughby 1939 WC-22 1 SR/1 0.22 Y C84 OGF 100 p Tur 1520 Inner gorge channel adjacent failure Willoughby 1939 WC-23 1 SR/1 0.47 Y C84 OGF 110 d Tur 1600 Planar between converging tributaries Willoughby 1939 WC-24 1 SR/1 0.26 Y C73 OGF 90 c Tur 1720 Channel head hollow failure Willoughby 1939 WC-25 1 SR/1 0.20 Y C71 OGF 100 c Tur 1960 Inner gorge Willoughby 1939 WC-26 1 SR/1 0.12 Y C71 OGF 100 c Tur 1920 Inner gorge Willoughby 1939 WC-27 1 SR/1 0.22 Y C71 OGF 100 c Tur 1860 Inner gorge Willoughby 1939 WC-28 1 SR/1 0.29 Y C71 OGF 110 c Tur 1960 Channel head hollow failure Willoughby 1939 WC-29 1 SR/1 0.96 Y C74 OGF 100 c Tur 1320 Channel head hollow failure Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Willoughby 1939 WC-30 1 SR/1 0.23 Y C72 OGF 80 c Tur 1520 Convergent channel sidewall Willoughby 1939 WC-31 1 SR/1 0.15 Y C74 OGF 90 c Tur 1320 Inner gorge Willoughby 1939 WC-32 1 SR/1 0.13 Y C74 OGF 90 c Tur 1200 Inner gorge Willoughby 1939 WC-33 1 SR/1 0.44 Y C72 OGF 90 c Tur 1080 Inner gorge Willoughby 1939 WC-34 1 SR/1 0.10 Y C72 OGF 85 p Tur 920 Inner gorge Willoughby 1939 WC-35 1 SSDS/3 0.34 Y C72 OGF 80 p Tur 840 Inner gorge Willoughby 1939 WC-36 1 SSDS/3 0.28 Y C72 OGF 90 p Tur 880 Inner gorge Willoughby 1939 WC-37 1 SSDS/3 0.55 Y C82 OGF 80 p Tur 800 Inner gorge Willoughby 1939 WC-38 1 SSDS/3 1.09 Y C82 OGF 80 p Tur 760 Inner gorge Willoughby 1975 WC-1 1 LPDS/p 2.23 Y C106 OGF 100 C Two 1960 Willoughby 1975 WC-2 1 SR/d 0.56 Y C107 OGF 105 C Two 2000 Willoughby 1975 WC-4 1 SR/d 0.55 Y C102 R 75 P Two 920 H3160 Sidecast Willoughby 1975 WC-5 1 LPDS/p 2.49 Y C93 OGF 100 D Two 2320 Willoughby 1975 WC-6 1 LPDS/p 0.71 Y C84 OGF 85 C Two 1480 Willoughby 1975 WC-7 1 LPDS/p 5.56 Y C92 OGF 85 P Two 2400 Willoughby 1975 WC-8 1 DBF/d 48.73 Y C92 R 90 C Two 2240 H3200 Headwall Sidecast Willoughby 1975 WC-9 1 SR/d 0.31 Y C92 OGF 85 C Two 1840 Willoughby 1975 WC-10 1 SR/d 0.72 Y C92 OGF 75 P Two 1600 Willoughby 1975 WC-11 1 SR/d 0.30 Y C92 OGF 75 P Two 1400 Willoughby 1975 WC-12 1 SR/d 0.36 Y C92 OGF 100 P Two 1320 Willoughby 1975 WC-13 1 DBF/d 1.42 Y C90 CC 100 P Two 2200 Willoughby 1975 WC-14 1 DBF/d 0.89 Y C90 R 100 C Two 2120 H3200 Spur sidecast Willoughby 1975 WC-15 1 SR/d 2.01 Y C90 R 85 C Two 1680 H3200 Spur sidecast Willoughby 1975 WC-16 1 DBF/d 0.60 Y C84 R 70 C Two 1720 H3230 Sidecast Willoughby 1975 WC-17 1 SR/d 0.42 Y C71 L 95 C Two 1880 H3230 Landing Willoughby 1975 WC-18 1 SR/d 0.26 Y C72 OGF 90 C Two 1400 Willoughby 1998 WC-1 1 SR/d 1.43 Y C107 CC 65 C Two 2440 HOLLOW FAILURE ON DEEP SEATED Willoughby 1998 WC-2 1 SR/d 0.25 Y C107 CC 75 C Two 2000 HOLLOW FAILURE ON DEEP SEATED Willoughby 1998 WC-3 1 SR/d 0.84 Y C105 CC 75 C Two 1600 HOLLOW FAILURE Willoughby 1998 WC-4 1 SR/d 0.88 Y C105 CC 106 C Two 1160 INNER GORGE FAILURE Willoughby 1998 WC-5 1 DBF/d 0.73 Y C105 CC 55 C Two 1720 HOLLOW FAILURE INTO DEBRIS FLOW Willoughby 1998 WC-6 1 DBF/d 1.10 Y C107 CC 55 C Two 2120 HOLLOW FAILURE INTO DEBRIS FLOW Willoughby 1998 WC-7 1 SR/d 0.23 N NA CC 55 P Qo 560 IN UNIT FAILURE Willoughby 1998 WC-8 1 DBF/d 3.43 Y C93 CC 65 C Two 2240 HOLLOW Willoughby 1998 WC-9 1 SR/d 0.20 Y C93 CC 85 C Two 2120 HOLLOW Willoughby 1998 WC-10 1 DBF/d 0.19 Y C93 CC 65 C Two 2120 HOLLOW Willoughby 1998 WC-11 1 SR/d 0.61 Y C93 CC 110 P Two 1760 INNER GORGE ON UPPER WILLOUGHBY Willoughby 1998 WC-12 1 SR/d 0.27 Y C93 CC 55 P Two 1560 INNER GORGE ON UPPER WILLOUGHBY Willoughby 1998 WC-13 1 DBF/d 2.51 Y C92 R 85 C Two 2280 HOLLOW BELOW ROAD CROSSING Willoughby 1998 WC-14 1 SR/d 0.38 Y C84 CC 85 P Two 1960 INNER GORGE Willoughby 1998 WC-15 1 SR/d 0.47 Y C84 CC 65 P Two 1800 INNER GORGE Willoughby 1998 WC-16 1 SR/d 0.83 Y C90 CC 75 C Two 2080 HOLLOW Willoughby 1998 WC-17 1 SR/d 0.31 Y C90 CC 55 C Two 1800 HOLLOW Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Willoughby 1998 WC-18 1 SR/d 0.39 Y C90 CC 75 C Two 2040 HOLLOW Willoughby 1998 WC-19 1 SR/d 0.71 Y C84 CC 75 C Two 1200 HOLLOW Willoughby 1998 WC-20 1 SR/d 0.57 Y C84 CC 65 C Two 1160 HOLLOW Willoughby 1998 WC-21 1 DBF/d 0.19 Y C84 CC 55 C Two 1920 HOLLOW Willoughby 1998 WC-22 1 SR/d 0.29 N NA CC 55 C Two 1840 IN UNIT FAILURE Willoughby 1998 WC-23 1 SR/d 0.20 Y C84 CC 55 C Two 1800 HOLLOW ABOVE INNER GORGE Willoughby 1998 WC-24 1 SR/d 0.46 Y C84 CC 55 C Two 1720 HOLLOW Willoughby 1998 WC-25 1 SR/d 0.70 Y C84 CC 65 C Two 1720 HOLLOW Willoughby 1998 WC-26 1 DBF/d 0.32 Y C84 L 65 C Two 1720 HOLLOW BELOW LANDING SPUR Willoughby 1998 WC-27 1 DBF/d 0.52 Y C84 CC 55 C Two 1560 HOLLOW AT CHANNEL HEAD Willoughby 1998 WC-28 1 DBF/d 0.07 Y C84 L 65 C Two 1360 SMALL DBF BELOW ROAD LANDING Willoughby 1998 WC-29 1 DBF/d 0.11 Y C84 L 65 C Two 1360 SMALL DBF BELOW ROAD LANDING Willoughby 1998 WC-30 1 DBF/d 0.17 Y C79 CC 65 C Two 1440 HOLLOW Willoughby 1998 WC-31 1 DBF/d 0.15 Y C79 CC 65 C Two 1240 HOLLOW Willoughby 1998 WC-32 1 DBF/d 0.14 Y C81 CC 75 C Two 1120 SMALL HOLLOW FAILURE Willoughby 1998 WC-33 1 DBF/d 0.27 Y C77 CC 55 C Two 1120 SMALL HOLLOW FAILURE Willoughby 1998 WC-34 1 DBF/d 0.14 Y C75 CC 55 C Two 1080 SMALL HOLLOW FAILURE Willoughby 1998 WC-36 1 SR/d 2.91 Y C74 CC 75 C Two 1440 LARGE HOLLOW FAILURE Willoughby 1998 WC-37 1 SR/d 0.59 Y C74 CC 75 D Two 800 INNER GORGE FAILURE Winfield 1975 WIN-18 1 SR/d 0.14 Y C735 CC 85 P Qo 960 Winfield 1975 WIN-19 1 SR/d 0.07 Y C735 CC 80 P Qo 920 Winfield 1975 WIN-20 1 SR/d 0.42 Y C735 CC 70 C Qo 880 Winfield 1975 WIN-21 1 SR/d 0.08 Y C735 CC 70 C Qo 1000 Winfield 1975 WIN-22 1 SR/d 0.06 Y C735 CC 70 C Qo 920 Winfield 1975 WIN-23 1 SR/d 0.12 Y C735 CC 70 C Qo 880 Winfield 1975 WIN-24 1 SR/d 0.12 Y C735 CC 70 P Qo 840 Winfield 1975 WIN-25 1 SR/d 0.08 Y C735 CC 70 P Qo 840 Winfield 1975 WIN-26 1 SR/d 0.27 Y C797 CC 75 C Two 1680 In Unit Convergent Hollow Winfield 1975 WIN-27 1 SR/d 0.54 Y C809 CC 65 C Thts 2000 In Unit Convergent Hollow Winfield 1975 WIN-28 1 SR/d 0.66 Y C809 CC 65 C Thts 1960 In Unit Convergent Hollow Winfield 1975 WIN-29 1 SR/d 0.58 Y C809 CC 65 C Thts 1840 In Unit Convergent Hollow Winfield 1975 WIN-30 1 SR/d 0.66 Y C809 CC 65 C Thts 1640 In Unit Convergent Hollow Winfield 1975 WIN-31 1 SR/d 0.59 Y C809 CC 65 C Thts 1480 In Unit Convergent Hollow Winfield 1975 WIN-32 1 SR/d 0.84 Y C809 CC 65 C Thts 1640 In Unit Convergent Hollow 589 0.06 50 520 min 48.73 126 3480 max 1.60 80 1802 mean 3.39 15 529 standard deviation 940.43 sum Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Hell Roaring 1975 HR-1 2 SR/d 3.80 Y A-1 SGF 60 P Thsr 320 Mainstem Bank Failure Hell Roaring 1975 HR-2 2 SR/d 0.15 Y A-1 SGF 60 C Thsr 280 Mainstem Bank Failure Hell Roaring 1975 HR-3 2 SR/d 0.36 Y A-1 SGF 60 P Thsr 1520 Mainstem Bank Failure Hell Roaring 1975 HR-4 2 SR/d 0.48 Y A-1 SGF 60 P Thsr 200 Mainstem Bank Failure Hell Roaring 1975 HR-5 2 SR/d 0.15 Y A-1 SGF 60 C Thsr 960 Mainstem Bank Failure Hell Roaring 1975 HR-6 2 SR/d 0.21 Y A-1 SGF 60 C Thsr 240 Mainstem Bank Failure Hell Roaring 1998 HR-16 2 SR/d 37.06 Y A1 CC 55 C Thsr 440 MEANDER BEND Hell Roaring 1998 HR-17 2 SR/d 60.02 Y A1 CC 55 C Thsr 360 LARGE TERRACE COMPLEX ON HOH RIVER Winfield 1975 WIN-1 2 SR/d 0.13 Y C768 CC 65 C Twos 1680 Winfield 1975 WIN-2 2 SR/d 0.23 Y C768 CC 65 C Twos 1640 Winfield 1975 WIN-3 2 SR/d 0.63 Y C768 R 65 C Twos 1720 Winfield 1975 WIN-4 2 SR/d 0.64 Y C742 L 65 C Twot 1560 Headwall landing Winfield 1975 WIN-5 2 DBF/d 0.23 Y C765 CC 65 C Thts 1920 Road Drainage Winfield 1975 WIN-6 2 DBF/d 0.25 Y C765 CC 65 C Thts 2000 Road Drainage Winfield 1975 WIN-7 2 DBF/d 0.56 Y C789 R 70 C Thts 2000 H1170 Sidecast Winfield 1975 WIN-8 2 DBF/d 0.86 Y C789 R 90 C Thts 2000 H1170 Sidecast Winfield 1975 WIN-9 2 DBF/d 2.29 Y C789 CC 60 C Thts 1920 In Unit below H1170 Winfield 1975 WIN-10 2 SR/d 0.45 Y C790 CC 75 C Thts 1560 In Unit below H1170 Winfield 1975 WIN-11 2 DBF/d 0.19 Y C791 R 80 C Thts 1880 Unknown Road Number Winfield 1975 WIN-12 2 DBF/d 0.30 Y C791 CC 85 C Thts 1720 Winfield 1975 WIN-13 2 DBF/d 0.41 Y C791 CC 85 C Thts 1800 Winfield 1975 WIN-14 2 DBF/d 0.30 Y C791 R 85 C Thts 1960 Sidecast Failure Winfield 1975 WIN-15 2 SR/d 0.20 Y C791 CC 100 C Thts 1700 In unit Toe slope Winfield 1975 WIN-16 2 DBF/d 3.14 Y C791 R 85 C Thts 1760 Sidecast/Stream crossing Winfield 1975 WIN-17 2 DBF/d 3.93 Y C791 R 85 C Thts 1640 Winfield 1975 WIN-35 2 SR/d 0.97 Y C851 CC 55 C Thts 960 Winfield 1975 WIN-36 2 SR/d 2.96 Y C846 R 55 C Thts 1200 St. Regis Road Winfield 1975 WIN-37 2 SR/d 1.03 Y C848 CC 55 C Thts 1120 Winfield 1975 WIN-38 2 SR/d 1.99 Y C842 CC 65 C Thts 1200 Winfield 1975 WIN-39 2 SR/d 0.95 Y C840 CC 65 C Thts 1160 Winfield 1975 WIN-40 2 SR/d 1.17 Y C843 CC 65 C Thts 1080 Winfield 1975 WIN-41 2 DSP 1.28 Y C823 CC 65 C Thts 880 Winfield 1975 WIN-42 2 SR/d 1.12 Y C823 CC 65 C Thts 1000 Winfield 1975 WIN-43 2 SR/d 0.35 Y C821 CC 65 C Thts 960 Winfield 1975 WIN-44 2 DBF/d 8.30 Y C821 R 65 C Thts 1000 Spur off of St. Regis Road Winfield 1998 WIN-1 2 SR/d 0.42 Y C768 CC 110 C Two 1440 INNER GORGE FAILURE Winfield 1998 WIN-2 2 SR/d 0.10 Y C791 R 85 C Thc 1880 ROAD FILLSLOPE FAILURE IN HOLLOW Winfield 1998 WIN-3 2 SR/d 0.32 Y C791 CC 75 D Thc 1560 INNER GORGE Winfield 1998 WIN-4 2 DBF/d 0.25 Y C790 CC 75 P Thc 1680 MIDSLOPE IN UNIT HOLLOW FAILURE Winfield 1998 WIN-5 2 DBF/d 2.68 Y C811 CC 65 C Thts 1640 MIDSLOPE IN UNIT HOLLOW FAILURE Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Winfield 1998 WIN-6 2 DBF/d 0.57 Y C834 L 55 C Thts 1800 LANDING IN RIDGETOP HOLLOW, LARGE DBF Winfield 1998 WIN-7 2 SR/d 0.17 Y C836 CC 115 C Thts 1240 SMALL INNER GORGE FAILURE Winfield 1998 WIN-8 2 SR/d 0.16 Y C836 CC 115 C Thts 1200 SMALL INNER GORGE FAILURE Winfield 1998 WIN-9 2 SR/d 0.19 Y C836 CC 115 C Thts 1160 SMALL INNER GORGE FAILURE Winfield 1998 WIN-10 2 SR/d 0.28 Y C833 CC 55 C Thts 1560 SMALL INNER GORGE FAILURE Winfield 1998 WIN-11 2 SR/d 0.29 Y C833 CC 55 C Thts 1280 SMALL INNER GORGE FAILURE Winfield 1998 WIN-12 2 SR/d 0.23 Y C830 CC 55 C Thts 1440 SMALL INNER GORGE FAILURE Winfield 1998 WIN-13 2 SR/d 0.09 Y C830 CC 110 C Thts 1400 SMALL INNER GORGE FAILURE Winfield 1998 WIN-14 2 SR/d 0.15 Y C829 CC 110 C Thts 1360 SMALL INNER GORGE FAILURE Winfield 1998 WIN-15 2 SR/d 0.12 Y C829 CC 110 P Thts 1840 SMALL INNER GORGE FAILURE Winfield 1998 WIN-18 2 SR/d 6.09 N NA CC 55 P Thts 920 LARGE IN UNIT FAILURE 51 0.09 55.00 200 min 60.02 115.00 2000 max 2.93 73.33 1348 mean 9.62 18.80 499 standard deviation 149.22 sum Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Elk Creek 1998 EC-27 3 LPDS/p 59.93 Y C621 CC 106 C Two 2200 LARGE DEEP SEATED Elk Creek 1998 EC-33 3 LPDS/p 32.64 Y C638 OGF 75 C Two 2400 OLD DEEP SEATED IN HDWTRS OF DRY CREEK Owl Creek 1975 OC-30 3 LPDS/p 4.46 Y C562 OGF 75 P Twoc 1200 Deep seated stream adjacent Owl Creek 1998 OC-28 3 LPDS/p 2.60 Y C499 CC 85 P Two 1440 ACTIVATED BY OC26&OC27 DBF Owl Creek 1998 OC-31 3 LPDS/p 22.74 Y C499 CC 85 C Two 1920 LARGE DEEPSEATED/SHALLOW RAPID AT TOE Owl Creek 1998 OC-50 3 LPDS/p 6.79 N NA CC 55 D Two 2280 OLD DORMANT DEEP SEATED FAILURE 2.60 55 1200 min 59.93 106 2400 max 21.53 80 1907 mean 20.27 15 445 standard deviation 129.16 sum Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Elk Creek 1975 EC-37 4 SR/d 2.12 Y C646 R 105 P Qo 720 Maple Creek Inner gorge Elk Creek 1975 EC-38 4 SR/d 0.35 Y C602 CC 100 C Qo 480 Maple Creek Inner gorge Elk Creek 1975 EC-39 4 SR/d 0.50 Y C602 CC 90 C Qo 480 Maple Creek Inner gorge Elk Creek 1975 EC-40 4 SR/d 0.61 Y C602 CC 75 C Qo 480 Elk Creek 1975 EC-41 4 SR/d 0.50 Y C654 R 75 C Qo 560 Elk Creek 1975 EC-42 4 SR/d 0.99 Y C661 CC 75 C Qo 520 Elk Creek 1975 EC-47 4 SR/d 0.12 Y C687 CC 85 P Qo 160 Small inner gorge Elk Creek 1975 EC-48 4 SR/d 0.13 Y C687 CC 60 P Two 160 Elk Creek 1998 EC-32 4 SR/d 0.27 N NA CC 100 C Two 760 TERRACE ABOVE MAPLE CREEK Elk Creek 1998 EC-48 4 SR/d 0.32 Y C602 CC 110 C Qo 600 INNER GORGE ON MAPLE CREEK TERRACE Elk Creek 1998 EC-49 4 SR/d 0.35 Y C602 CC 120 C Qo 480 INNER GORGE ON MAPLE CREEK Elk Creek 1998 EC-50 4 SR/d 2.08 Y C602 CC 105 C Qo 480 INNER GORGE ON MAPLE CREEK Elk Creek 1998 EC-51 4 SR/d 0.72 Y C602 CC 110 C Qo 520 INNER GORGE ON LOWER MAPLE CREEK Elk Creek 1998 EC-52 4 SR/d 0.43 Y C602 CC 100 C Qo 520 INNER GORGE ON LOWER MAPLE CREEK Elk Creek 1998 EC-53 4 SR/d 0.55 Y C602 CC 100 C Qo 440 INNER GORGE ON LOWER MAPLE CREEK Elk Creek 1998 EC-54 4 SR/d 0.49 N NA CC 90 P Qo 360 HOH TERRACE Elk Creek 1998 EC-55 4 SR/d 0.21 N NA CC 90 P Qo 400 HOH TERRACE Elk Creek 1998 EC-56 4 SR/d 0.04 N NA CC 85 P Qo 440 HOH TERRACE Elk Creek 1998 EC-57 4 SR/d 0.16 N NA CC 90 P Qo 400 HOH TERRACE Elk Creek 1998 EC-58 4 SR/d 0.34 N NA CC 85 P Qo 400 HOH TERRACE Hell Roaring 1975 HR-7 4 SR/d 0.48 Y A-1 SGF 100 C Qo 280 Inner gorge failure Hell Roaring Creek Hell Roaring 1975 HR-8 4 SR/d 0.44 Y A-1 SGF 85 C Qo 280 Inner gorge failure Hell Roaring Creek Hell Roaring 1998 HR-11 4 SR/d 0.35 Y C3 CC 90 P Qo 440 SMALL INNER GORGE FAILURE Hell Roaring 1998 HR-12 4 SR/d 0.38 Y C3 CC 90 P Qo 480 SMALL INNER GORGE FAILURE Hell Roaring 1998 HR-13 4 SR/d 0.32 Y C3 CC 90 P Qo 480 SMALL INNER GORGE FAILURE Hell Roaring 1998 HR-14 4 SR/d 106.15 Y A1 CC 80 C Qo 400 LARGE TERRACE COMPLEX Hell Roaring 1998 HR-15 4 SR/d 5.41 Y C23 CC 80 C Thsr 440 LARGE HOLLOW FAILURE Owl Creek 1975 OC-67 4 SR/d 0.88 Y C590 R 65 P Qo 520 H1060 Owl Creek 1975 OC-68 4 SR/d 0.34 Y C497 R 65 P Qo 560 H1060 Owl Creek 1975 OC-69 4 SR/d 0.52 Y C497 R 65 P Qo 560 H1060 Owl Creek 1998 OC-82 4 LPDS/p 6.00 Y C497 R 95 C Qo 520 INNER GORGE OF OWL CREEK Owl Creek 1998 OC-83 4 LPDS/p 2.86 Y C497 CC 95 C Qo 560 INNER GORGE OF OWL CREEK Owl Creek 1998 OC-84 4 SPDS 0.92 Y C494 CC 95 C Qo 400 INNER GORGE OF OWL CREEK South Fork 1975 SF-1 4 SR/d 2.30 N NA R 55 P Ttr 1300 Road Sidecast Failure South Fork 1975 SF-2 4 SR/d 0.19 N NA R 55 D Ttr 1220 Road Cutslope Failure Tower Creek 1998 TC-4 4 SR/d 0.24 Y C128 L 55 P Two 560 LANDING DEBRIS FAILURE Tower Creek 1998 TC-21 4 SR/d 3.38 Y C116 CC 100 C Qo 600 INNER GORGE Tower Creek 1998 TC-22 4 SR/d 0.34 Y C116 CC 105 C Qo 520 SMALL INNER GORGE FAILURE ON TOWER Willoughby 1975 WC-3 4 SR/d 0.46 Y C101 CC 75 C Qo 480 Willoughby 1998 WC-35 4 SR/d 12.72 Y C83 CC 100 P Qo 520 LONG INNER GORGE ON TRIB TO WILLOUGHBY Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Willoughby 1998 WC-38 4 SR/d 1.24 Y A1 CC 55 P Qo 400 HOH RIVER TERRACE Winfield 1975 WIN-33 4 SR/d 0.17 Y C863 CC 55 P Thts 440 Yarding damage Winfield 1975 WIN-34 4 SR/d 0.18 Y C863 CC 55 P Thts 480 Yarding damage Winfield 1975 WIN-45 4 SR/d 0.69 N NA PIT 55 P Qo 320 Spoils failure towards Winfield Creek Winfield 1975 WIN-46 4 SR/d 0.92 N NA PIT 55 P Qo 320 Spoils failure towards Winfield Creek Winfield 1998 WIN-16 4 SPDS 0.73 Y C870 CC 25 C Qo 320 DEEP SEATED ON TERRACE WINFIELD Winfield 1998 WIN-17 4 SPDS 0.77 Y C870 CC 25 C Qo 320 DEEP SEATED ON TERRACE WINFIELD 47 0.04 25 160 min 106.15 120 1300 max 3.42 81 491 mean 15.29 21 199 standard deviation 160.67 sum Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Elk Creek 1975 EC-43 5 SR/d 1.28 Y C683 CC 105 C Qo 400 Glacial Terrace Hoh Red Cliffs Elk Creek 1975 EC-44 5 SR/d 2.24 Y C683 SGF 110 C Qo 400 Glacial Terrace mainstem Hoh Elk Creek 1975 EC-45 5 SR/d 0.41 Y B3 SGF 110 C Qo 360 Glacial Terrace mainstem Hoh Elk Creek 1975 EC-46 5 SR/d 1.23 Y C683 SGF 110 C Qo 400 Glacial Terrace mainstem Hoh Elk Creek 1998 EC-60 5 SR/d 11.77 Y A3 SGF 110 C Qo 440 HOH TERRACE RED CLIFFS Elk Creek 1998 EC-61 5 SR/d 3.12 Y A3 SGF 90 C Qo 440 HOH TERRACE Elk Creek 1998 EC-62 5 SR/d 2.43 Y A3 SGF 85 C Qo 320 HOH TERRACE Elk Creek 1998 EC-63 5 SR/d 3.87 Y A3 SGF 85 C Qo 400 HOH TERRACE South Fork 1975 SF-3 5 SR/d 0.42 Y A7 R 76 P Qta 720 Glacial Terrace Margin 0.41 76 320 min 11.77 110 720 max 2.98 98 431 mean 3.30 13 108 standard deviation 26.78 Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Elk Creek 1998 EC-68 6 LPDS/p 10.86 Y A3 SGF 75 C Two 280 HOH RIVER TERRACE South Fork 1975 SF-4 6 DSS/p 1.26 N NA OGF 75 P Qta 640 Glacial Terrace Margin South Fork 1975 SF-5 6 DSS/p 26.52 Y A7 OGF 55 P Qta 720 Glacial Terrace Margin South Fork 1975 SF-6 6 DSS/p 3.23 Y A7 OGF 65 P Qta 680 Glacial Terrace Margin South Fork 1998 SF-16 6 SR/d 0.38 N NA CC 55 P Qo 760 TERRACE FAILURE ONTO BENCH South Fork 1998 SF-17 6 SR/d 1.05 Y A7 R 55 P Qo 720 ROAD FILLSLOPE DELIVERS TO SOUTH FORK South Fork 1998 SF-18 6 SR/d 0.29 Y A7 R 55 P Qo 720 ROAD FILLSLOPE DELIVERS TO SOUTH FORK South Fork 1998 SF-19 6 LPD/p 4.08 Y A7 CC 25 C Qo 680 DEEP SEATED FAILURE IN SF TERRACE South Fork 1998 SF- 20 6 LPD/p 7.54 Y A7 CC 25 C Qo 560 DEEP SEATED FAILURE IN SF TERRACE South Fork 1998 SF- 21 6 LPD/p 7.52 Y A7 CC 55 C Qo 680 DEEP SEATED FAILURE IN SF TERRACE South Fork 1998 SF- 22 6 LPD/p 5.20 Y A7 CC 55 C Qo 640 DEEP SEATED FAILURE IN SF TERRACE Spruce 1998 SC-35 6 PDSS 1.91 Y A5 SGF 25 P Qo 400 TERRACE UNDERCUT BY CHANNEL MEANDER Winfield 1998 WIN-19 6 LPDS/p 6.83 Y A1 SGF 55 C Two 360 OUTSIDE MEANDER BEND ON HOH 13 0.29 0.86 25 280 min 26.52 75 760 max 5.90 52 603 mean 6.74 16 150 standard deviation 76.68 sum Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Chan.Seg# Land Use Slope Slope Form Elev. Comments South Fork 1999 SF-262 7 LPDS/3 45.0 Y A7 NA 11 P 636 Younger alpine glaciofluvial/glaciolacustrine and till deposits Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module South Fork 1999 SF-278 7 LPDS/4 5.6 Y C450 NA 21 C 2216 Turbidite sandstone and conglomerate with minor siltstone and argillite Spruce 1999 SC-250 7 LPDS/4 280.7 N NA NA 12 P 848 Younger alpine glaciofluvial/glaciolacustrine and till deposits Owl Creek 1999 OC-261 7 LPDS/3 57.1 Y C473 NA 14 C 606 Younger alpine glaciofluvial/glaciolacustrine and till deposits Owl Creek 1999 OC-267 7 LPDS/3 82.2 Y C483 NA 25 C 770 Younger alpine glaciofluvial/glaciolacustrine and till deposits Owl Creek 1999 OC-271 7 LPDS/3 59.9 Y C490 NA 42 D 1536 Turbidite sandstone and conglomerate with minor siltstone and argillite Owl Creek 1999 OC-273 7 LPDS/2 4.3 N NA NA 31 D 1665 Turbidite sandstone and conglomerate with minor siltstone and argillite Owl Creek 1999 OC-274 7 LPDS/2 4.8 Y C480 NA 36 C 1570 Turbidite sandstone and conglomerate with minor siltstone and argillite Owl Creek 1999 OC-288 7 LPDS/3 29.0 Y C509 NA 27 D 2803 Turbidite sandstone and conglomerate with minor siltstone and argillite Owl Creek 1999 OC-290 7 LPDS/3 17.8 Y C534 NA 36 C 2770 Turbidite sandstone and conglomerate with minor siltstone and argillite Owl Creek 1999 OC-291 7 LPDS/3 12.4 Y C539 NA 32 D 2880 Turbidite sandstone and conglomerate with minor siltstone and argillite Tower Creek 1999 TC-249 7 LPDS/4 60.3 Y B8 NA 16 D 510 Younger alpine glaciofluvial terrace deposits and till(?) Elk Creek 1999 EC-251 7 LPDS/3 95.9 Y C686 NA 12 C 459 Younger alpine glaciofluvial terrace deposits Elk Creek 1999 EC-252 7 LPDS/4 16.3 Y A1,B5 NA 14 C 400 Younger alpine glaciofluvial terrace deposits Elk Creek 1999 EC-253 7 LPDS/3 62.0 Y C684 NA 18 C 443 Younger alpine glaciofluvial terrace deposits Elk Creek 1999 EC-264 7 LPDS/3 82.8 Y C654 NA 25 C/D 681 Younger alpine glaciofluvial/glaciolacustrine and till deposits Elk Creek 1999 EC-265 7 LPDS/3 7.1 Y C667 NA 25 C 479 Younger alpine glaciofluvial terrace deposits and till(?) Willoughby 1999 W-230 7 LPDS/3 35.9 Y C70 NA 49 C 2007 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-236 7 LPDS/3 5.7 Y C72 NA 36 C/D 1707 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-238 7 LPDS/2 32.2 Y C92 NA 51 C 2366 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-242 7 LPDS/2 66.7 Y C107 NA 47 C 2488 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-244 7 LPDS/3 3.8 Y C86 NA 36 C 1041 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-246 7 LPDS/4 19.9 Y C94 NA 42 C 1417 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Willoughby 1999 W-247 7 LPDS/3 23.3 Y C102 NA 49 C 1970 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Winfield 1999 WC-255 7 LPDS/4 343.4 Y C892 NA 11 C/D 499 Younger alpine glaciofluvial terrace deposits and till(?) Winfield 1999 WC-276 7 LPDS/4 86.5 Y C873 NA 27 P 996 Thick-bedded sandstone with minor thin-bedded siltstone and sandstone Winfield 1999 WC-281 7 LPDS/3 6.0 Y C743 NA 14 C 1575 Older alpine glacial drift over slate and phyllite. Alder Creek 1999 AC-229 7 LPDS/2 42.1 Y C50 NA 27 D 1226 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Alder Creek 1999 AC-231 7 LPDS/3 12.6 Y C49 NA 31 C 1429 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Alder Creek 1999 AC-232 7 LPDS/3 3.6 Y C47 NA 31 D 1414 Turbidite sandstone, siltstone, and argillite with variable bedding thickness Hell Roaring 1999 HR-221 7 LPDS/2 17.4 Y C13 NA 34 D 1424 Turbidite sandstone, siltstone, and argillite with variable bedding thickness 31 0.9375 3.60 11 400 min 343.40 51 2880 max 52.33 29 1382 mean 74.10 11 757 standard deviation 1622.30 sum Middle Hoh WAU #200607 Final Report: 4-1-2000 Mass Wasting Module Sub-basin Year I.D. No. MWMU Process Certainty Area Del. Channel Seg# Land Use Slope Slope Form Rock Unit Elev. Comments Spruce 1939 SC-12 8 SR/1 0.37 Y T2wetland OGF 100 p Qt 400 Shallow Rapid on terrace delivers to wetlands Fi n a l R e p o r t : 4 - 1 - 2 0 0 0 M a ss W a s t i n g M o d u l e FO R M A -2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 1 : W i l l o u g h b y - H u e l s d o n k H e a d w a t e r s De s c r i p t i o n : St e e p h e a d w a t e r h i l l s l o p e s a n d s t r e a m c h a n n e l a d j a c en t s i d e s l o p e s w i t h i n t h e W e s t e r n O l y m p i c L i t h i c A s semblage ro c k u n i t s . O c c u p i e s 2 4 % o f t h e M i d d l e H o h W A U i n t he u p p e r r e a c h e s o f A l d e r , E l k , H e l l R o a r i n g , O w l , South Fork, Sp r u c e , T o w e r , W i l l o u g h b y a n d W i n f i e l d s u b - w a t e r s h e ds . S e e M a p A - 2 . Ma t e r i a l s : Pa r e n t m a t e r i a l i s p r i m a r i l y s a n d s t o n e a n d c o n g l o m e ra t e o f t h e W e s t e r n O l y m p i c L i t h i c A s s e m b l a g e r o c k s . Thin (five fe e t o r l e s s d e e p ) s o i l s o v e r b e d r o c k c o n s i s t o f g r av e l l y t o c o b b l y s i l t l o a m (3 0 % g r e a t e r t h a n 3 i n c h e s d i a m e t e r , 7 0 % le s s t h a n 2 . 0 m m d i a m e t e r ) . La n d f o r m : Co n v e r g e n t t o p o g r a p h y f o r m i n g t h e h e a d s o f 1 st a n d 2 nd o r d e r c h a n n e l s , i n n e r go r g e s o f 1 st a n d 2 nd o r d e r c h a n n e l s , a n d p l a n a r a n d d i v e r g e n t s l o p e s o f i n t e r m e d i a t e r i d g e s . Sl o p e : M i n : 5 0 % M a x : 1 2 6 % M e a n : 8 0 % S t a n d a r d D e v i a t i o n : 1 5 n = 5 8 9 El e v a t i o n : Mi n : 5 2 0 ' M a x : 3 4 8 0 ' M e a n : 1 8 0 2 ' S t a n d a r d D e v i a t i o n : 529 n=589 To t a l A r e a : 13 0 6 2 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n MW M U 1 i s 9 4 0 . 4 3 a c r e s . Mi n : 0 . 0 6 a c . M a x : 4 8 . 7 3 a c . M e a n : 1 . 6 a c . S t a n d a r d D ev i a t i o n : 3 . 3 9 n = 5 8 9 MW P r o c e s s e s : Pr e d o m i n a n t l y s h a l l o w r a p i d l a n d s l i d e s a n d d e b r i s f lo w s . R e l a t i v e l y m i n o r n u m b e r s o f d e e p s e a t e d l a n d s lides in c l u d e d w i t h i n t h i s M W M U . Se e F o r m A 1 & A - 3 . Fo r e s t P r a c t i c e S e n s i t i v i t y : Hi g h . 80 % o f i n v e n t o r i e d l a n d s l i d e s w e r e a s s o c i a t e d w i t h fo r e s t p r a c t i c e l a n d u s e s . MW P o t e n t i a l : Hi g h . Ob s e r v e d l a n d s l i d e r a t e o f 9 . 9 8 l a n d s l i d e s / y e a r b e t we e n 1 9 3 9 - 1 9 9 8 . De l i v e r y P o t e n t i a l : H i g h (5 3 9 / 5 8 9 ) 95 % of l a n d s l i d e s d e l i v e r t o s t r e a m c h a n n e l s . Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o s t r e a m c h a n n e l s . Ha z a r d P o t e n t i a l R a t i n g : Hi g h . Tr i g g e r M e c h a n i s m ( s ) : Cl e a r - c u t t i n g ( e v e n a g e t i m b e r m a n a g e m e n t ) o f s l o p e s b e t w e e n 2 5 % a n d 1 2 6 % r e d u c e s t h e ef f e c t i v e s o i l c o h e s i o n c o n t r i b u t e d b y t r e e r o o t s t re n g t h o n h i l l s l o p e s i n c l o s e p r o x i m i t y t o s t r e a m c hannels. The loss of ef f e c t i v e s o i l c o h e s i o n i n c r e a s e s t h e l i k e l i h o o d o f s h a l l o w r a p i d h i l l s l o p e f a i l u r e a n d r e s u l t i n g d e b r is flow deposition of w a t e r , w o o d a n d s e d i m e n t i n t o 1 st , 2 nd a n d 3 rd o r d e r s t r e a m c h a n n e l s . Si d e c a s t r o a d c o n s t r u c t i o n i n c o r p o r a t i n g l o g c r i b s to s u p p o r t f i l l s l o p e s i n s t e e p , c o n v e r g e n t h e a d w a l l s, has triggered ma n y e x t r e m e l y d a m a g i n g d e b r i s f l o w s . I n a d e q u a t e r o ad d r a i n a g e ( l a c k o f c u l v e r t s , u n d e r s i z e d , a n d u n - m aintained cu l v e r t s , h a s c o n t r i b u t e d t o t h e s e d e b r i s f l o w e v e n ts . C o n c e n t r a t i n g r o a d d r a i n a g e i n t o c o n v e r g e n t t o p ography at the he a d s o f c h a n n e l s i n c r e a s e s t h e l i k e l i h o o d o f c h a n n el e r o s i o n a n d a s s o c i a t e d s t r e a m b a n k f a i l u r e s . Co n f i d e n c e : Hi g h FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 2 : Wi n f i e l d De s c r i p t i o n : St e e p h e a d w a t e r h i l l s l o p e s a n d s t r e a m c h a n n e l a d j a c en t s i d e s l o p e s w i t h i n t h e H o h L i t h i c A s s e m b l a g e r o c k units. Oc c u p i e s 2 . 6 % o f t h e M i d d l e H o h W A U i n t h e l o w e r r e ac h e s o f A l d e r a n d H e l l R o a r i n g , a n d t h e u p p e r r e a ches of Wi n f i e l d . S e e M a p A - 2 . Ma t e r i a l s : Pa r e n t m a t e r i a l s a r e p r i m a r i l y f i n e g r a i n e d s a n d s t o ne a n d s i l t s t o n e , w h i c h h a s b e e n s h e a r e d , d e f o r m e d , and faulted. Th i n ( 3 0 - 4 8 i n c h e s ) s o i l s o v e r b e d r o c k c o n s i s t o f g ra v e l l y t o c o b b l y s i l t l o a m (2 0 % g r e a t e r t h a n 3 i n c h e s d i a m e t e r , 45 % l e s s t h a n 2 . 0 m m d i a m e t e r ) . La n d f o r m : Co n v e r g e n t t o p o g r a p h y f o r m i n g t h e h e a d s o f 1 st a n d 2 nd o r d e r c h a n n e l s , i n n e r go r g e s o f 1 st a n d 2 nd o r d e r c h a n n e l s , a n d p l a n a r a n d d i v e r g e n t s l o p e s o f i n t e r m e d i a t e r i d g e s . Sl o p e : Mi n : 5 5 % M a x : 1 1 5 % M e a n : 7 3 % S t a n d a r d D e v i a t i o n : 1 9 n = 5 1 El e v a t i o n : Mi n : 2 0 0 ' M a x : 2 0 0 0 ' M e a n : 1 3 4 8 ' S t a n d a r d D e v i a t i o n : 4 9 9 n = 5 1 To t a l A r e a : 14 2 7 . 2 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n M W M U 2 i s 1 4 9 . 2 2 a c r e s . Mi n : 0 . 0 9 a c . M a x : 6 0 . 0 2 a c . M e a n : 2 . 9 3 a c . S t a n d a r d De v i a t i o n : 9 . 6 2 a c . n = 5 1 MW P r o c e s s e s : Pr e d o m i n a n t l y s h a l l o w r a p i d l a n d s l i d e s ( 3 5 ) a n d d e b ri s f l o w s ( 1 5 ) . R e l a t i v e l y m i n o r n u m b e r s ( 1 ) o f d e e p seated la n d s l i d e s i n c l u d e d w i t h i n t h i s M W M U . Se e F o r m A 1 & A - 3 . Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Fo r e s t P r a c t i c e S e n s i t i v i t y : Hi g h . 80 % o f i n v e n t o r i e d l a n d s l i d e s w e r e a s s o c i a t e d w i t h fo r e s t p r a c t i c e l a n d u s e s . MW P o t e n t i a l : Hi g h . Ob s e r v e d l a n d s l i d e r a t e o f 2 . 2 2 l a n d s l i d e s / y e a r b e t we e n 1 9 7 5 - 1 9 9 8 . De l i v e r y P o t e n t i a l : Hi g h . 9 8 % o f i n v e n t o r i e d l a n d s l i d e s d e l i v e r t o s t r e am c h a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Hi g h Tr i g g e r M e c h a n i s m ( s ) : Cl e a r - c u t t i n g ( e v e n a g e t i m b e r m a n a g e m e n t ) o f s l o p e s b e t w e e n 5 5 % a n d 1 1 5 % r e d u c e s t h e ef f e c t i v e s o i l c o h e s i o n c o n t r i b u t e d b y t r e e r o o t s t re n g t h o n h i l l s l o p e s i n c l o s e p r o x i m i t y t o s t r e a m c hannels. The loss of ef f e c t i v e s o i l c o h e s i o n i n c r e a s e s t h e l i k e l i h o o d o f s h a l l o w r a p i d h i l l s l o p e f a i l u r e a n d r e s u l t i n g d e b r is flow deposition of w a t e r , w o o d a n d s e d i m e n t i n t o 1 st , 2 nd a n d 3 rd o r d e r s t r e a m c h a n n e l s . H i s t o r i c l o n g y a r d i n g d i s t a n ces has disturbed th e g r o u n d a n d s t u m p s w h i c h m a y c o n t r i b u t e t o f a i l u re . Si d e c a s t r o a d c o n s t r u c t i o n i n c o r p o r a t i n g l o g c r i b s to s u p p o r t f i l l s l o p e s i n s t e e p , c o n v e r g e n t h e a d w a l l s, has triggered ma n y e x t r e m e l y d a m a g i n g d e b r i s f l o w s . I n a d e q u a t e r o ad d r a i n a g e ( l a c k o f c u l v e r t s , u n d e r s i z e d , a n d u n - m aintained cu l v e r t s , h a s c o n t r i b u t e d t o t h e s e d e b r i s f l o w e v e n ts . C o n c e n t r a t i n g r o a d d r a i n a g e i n t o c o n v e r g e n t t o p ography at the he a d s o f c h a n n e l s i n c r e a s e s t h e l i k e l i h o o d o f c h a n n el e r o s i o n a n d a s s o c i a t e d s t r e a m b a n k f a i l u r e s . Co n f i d e n c e : Hi g h FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 3 : W e s t e r n O l y m p i c D e e p - s e a t e d ( O w l C r e e k , M a p A- 2 ) De s c r i p t i o n : De e p - s e a t e d l a n d s l i d e s o n l o w e r s l o p e s o f v a l l e y s i de w a l l s a n d i n n e r g o r g e s o f O w l C r e e k a n d tr i b u t a r i e s . Ma t e r i a l s : Sa n d s t o n e a n d c o n g l o m e r a t e o f t h e W e s t e r n O l y m p i c L it h i c A s s e m b l a g e r o c k s . S o i l a n d c o l l u v i u m co n s i s t o f s h a l l o w ( 3 0 - 4 8 " ) v e r y c h a n n e r y s i l t y c l a y l o a m ( 2 0 % g r e a t e r t h a n 3 i n c h e s , 4 5 % l e s s t h a n 2. 0 0 m m d i a m e t e r ) . La n d f o r m : Lo w e r s l o p e s o f v a l l e y s i d e w a l l s a n d i n n e r g o r g e s o f O w l C r e e k a n d t r i b u t a r i e s . Sl o p e : Mi n : 5 5 % M a x : 1 0 6 % M e a n : 8 0 % S t a n d a r d D e v i a t i o n : 1 5 n = 6 El e v a t i o n : M i n : 1 2 0 0 ' M a x : 2 4 0 0 ' M e a n : 1 9 0 7 ' S t a n d a r d D e v i a t i on: 445 n=6 To t a l A r e a : 19 5 . 6 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n MW M U 3 i s 1 2 9 . 2 a c r e s . Mi n : 2 . 6 0 a c . M a x : 5 9 . 9 3 a c . M e a n : 2 1 . 5 3 a c . S t a n d a r d D e v i a t i o n : 2 0 . 2 7 a c . n = 6 MW P r o c e s s e s : De e p - s e a t e d m a s s m o v e m e n t a s s o c i a t e d w i t h s t r u c t u r a l f a u l t i n g o f W e s t e r n O l y m p i c L i t h i c As s e m b l a g e r o c k s . Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Fo r e s t P r a c t i c e S e n s i t i v i t y : Hi g h . MW P o t e n t i a l : H i g h . Ob s e r v e d l a n d s l i d e r a t e o f 0 . 2 6 l a n d s l i d e s / y e a r b e t we e n 1 9 7 5 - 1 9 9 8 . De l i v e r y P o t e n t i a l : Hi g h . 5 0 % o f o b s e r v e d l a n d s l i d e s d e l i v e r t o s t r e a m ch a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Hi g h Tr i g g e r M e c h a n i s m ( s ) : De e p - s e a t e d l a n d s l i d e s i n O w l C r e e k a p p e a r t o b e c o nt r o l l e d b y t w o m a j o r p r o c e s s e s : W a t e r av a i l a b l e t o t h e l a n d s l i d e m a s s f r o m p r e c i p i t a t i o n an d r e d u c e d e v a p o t r a n s p i r a t i o n f r o m t i m b e r h a r v e s t and disturbance re s u l t i n g f r o m d e b r i s f l o w a n d d a m - b r e a k f l o o d s a t th e t o e o f t h e f a i l u r e s a l o n g t h e i n n e r g o r g e o f O w l Creek. In c r e a s e d w a t e r d e l i v e r y f r o m r o a d s y s t e m s i s a n o t h er c o n t r i b u t i n g f a c t o r . Co n f i d e n c e : Hi g h . FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 4 : Gl a c i a l G o r g e s De s c r i p t i o n : Sh o r t , m o d e r a t e l y s t e e p g l a c i a l a n d a l l u v i a l t e r r a c e m a r g i n s a n d i n n e r g o r g e s o f s t r e a m s w i t h i n t h e O l ympic Alpine Gl a c i a l r o c k u n i t s . O c c u p i e s 2 . 2 % o f t h e M i d d l e H o h W A U d i s t r i b u t e d t h r o u g h o u t a l l s u b - w a t e r s h e d s . S ee Map A-2. Ma t e r i a l s : Pa r e n t m a t e r i a l s a r e c o m p o s e d o f d e p o s i t s o f O l y m p i c a l p i n e g l a c i e r s i n c l u d i n g m o r a i n e s a n d s t r a t i f i e d deposits (sand, gr a v e l , s i l t , c l a y ) . I n c l u d e s h i g h r i v e r t e r r a c e s a lo n g m a j o r r i v e r c h a n n e l s t h a t m a y n o t b e d i r e c t l y associated with gl a c i a t i o n . R e l a t i v e l y t h i c k , n o n - c o h e s i v e s o i l s ( >6 0 i n c h e s ) o v e r l i e v a r i a b l y c o n s o l i d a t e d g l a c i a l deposits and consist of v e r y c o a r s e t o v e r y f i n e g r a v e l l y s a n d y l o a m (0 - 1 5 % g r e a t e r t h a n 3 i n c h e s d i a m e t e r , 8 5 - 1 0 0 % l e s s than 2.0 mm di a m e t e r ) . La n d f o r m : Ge n e r a l l y p l a n a r h i l l s l o p e s , t e r r a c e m a r g i n s , a n d st r e a m a d j a c e n t i n n e r - g o r g e s l o p e s f o r m e d i n g l a c i a l deposits. Sl o p e : Mi n : 2 5 % M a x : 1 2 0 % M e a n : 8 1 % S t a n d a r d D e v i a t i o n : 2 1 n = 4 7 El e v a t i o n : Mi n : 1 6 0 ' M a x : 1 3 0 0 ' M e a n : 4 9 1 ' S t a n d a r d D e v i a t i o n : 1 9 9 n = 4 7 To t a l A r e a : 12 1 9 . 6 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n M W M U 2 i s 1 6 0 . 6 7 a c r e s . Mi n : 0 . 0 4 a c . M a x : 1 0 6 . 1 5 a c . M e a n : 3 . 4 2 a c . S t a n d a r d D e v i a t i o n : 1 5 . 2 9 a c . n = 4 7 MW P r o c e s s e s : Pr e d o m i n a n t l y s h a l l o w r a p i d l a n d s l i d e s ( 4 2 ) . D e b r i s f l o w s ( 0 ) a n d d e e p s e a t e d l a n d s l i d e s ( 5 ) i n c l u d e d within this MW M U a r e r e l a t i v e l y f e w . Se e F o r m A 1 & A - 3 . Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Fo r e s t P r a c t i c e S e n s i t i v i t y : Hi g h . 96 % ( 4 5 / 4 7 ) o f i n v e n t o r i e d l a n d s l i d e s w e r e a s s o c i a t ed w i t h f o r e s t p r a c t i c e l a n d u s e s . MW P o t e n t i a l : Hi g h . Ob s e r v e d l a n d s l i d e r a t e o f 2 . 0 4 l a n d s l i d e s / y e a r b e t we e n 1 9 7 5 - 1 9 9 8 . De l i v e r y P o t e n t i a l : Hi g h . 7 9 % o f i n v e n t o r i e d l a n d s l i d e s d e l i v e r t o s t r e am c h a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Hi g h Tr i g g e r M e c h a n i s m ( s ) : Cl e a r - c u t t i n g ( e v e n a g e t i m b e r m a n a g e m e n t ) o f s l o p e s b e t w e e n 2 5 % a n d 1 2 0 % r e d u c e s t h e ef f e c t i v e s o i l c o h e s i o n c o n t r i b u t e d b y t r e e r o o t s t re n g t h o n h i l l s l o p e s i n c l o s e p r o x i m i t y t o s t r e a m c hannels. The loss of ef f e c t i v e s o i l c o h e s i o n i n c r e a s e s t h e l i k e l i h o o d o f s h a l l o w r a p i d h i l l s l o p e f a i l u r e a n d r e s u l t i n g d e b r is flow deposition of w a t e r , w o o d a n d s e d i m e n t i n t o s t r e a m c h a n n e l s . Si d e c a s t r o a d c o n s t r u c t i o n i n c o r p o r a t i n g l o g c r i b s to s u p p o r t f i l l s l o p e s o n s t e e p g l a c i a l t e r r a c e d e p o sits, has triggered ma n y s h a l l o w r a p i d l a n d s l i d e s . I n a d e q u a t e r o a d d r a i na g e ( l a c k o f c u l v e r t s , u n d e r s i z e d , a n d u n - m a i n t a i n ed culverts, ha s c o n t r i b u t e d t o t h e s e e v e n t s . C o n c e n t r a t i n g r o a d d r a i n a g e o n t o n o n - c o h e s i v e s o i l s i n c r e a s e s t h e l i k elihood of ch a n n e l e r o s i o n a n d a s s o c i a t e d s t r e a m b a n k f a i l u r e s . Co n f i d e n c e : Hi g h FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 5 : Ma i n s t e m T e r r a c e F a c e s De s c r i p t i o n : Sh o r t , m o d e r a t e l y s t e e p g l a c i a l a n d a l l u v i a l t e r r a c e m a r g i n s a d j a c e n t t o t h e m a i n s t e m o f t h e H o h R i v e r and South Fork. Oc c u p i e s 0 . 0 6 % o f t h e M i d d l e H o h W A U i n t h e E l k a n d S o u t h F o r k s u b - w a t e r s h e d s . S e e M a p A - 2 . Ma t e r i a l s : Pa r e n t m a t e r i a l s a r e c o m p o s e d o f d e p o s i t s o f O l y m p i c a l p i n e g l a c i e r s i n c l u d i n g m o r a i n e s a n d s t r a t i f i e d deposits (sand, gr a v e l , s i l t , c l a y ) . I n c l u d e s h i g h r i v e r t e r r a c e s a lo n g m a j o r r i v e r c h a n n e l s t h a t m a y n o t b e d i r e c t l y associated with gl a c i a t i o n . R e l a t i v e l y t h i c k , n o n - c o h e s i v e s o i l s ( >6 0 i n c h e s ) o v e r l i e v a r i a b l y c o n s o l i d a t e d g l a c i a l deposits and consist of v e r y c o a r s e t o v e r y f i n e g r a v e l l y s a n d y l o a m (0 - 1 5 % g r e a t e r t h a n 3 i n c h e s d i a m e t e r , 8 5 - 1 0 0 % l e s s than 2.0 mm di a m e t e r ) . La n d f o r m : Ge n e r a l l y p l a n a r t o m o d e r a t e l y c o n c a v e t e r r a c e m a r g in s a d j a c e n t t o t h e m a i n s t e m H o h a n d S o u t h F o r k r i v er channels. In s o m e a r e a s l a t e r a l m i g r a t i o n o f r i v e r c h a n n e l s h as u n d e r c u t a n d e f f e c t i v e l y o v e r s t e e p e n e d t h e t e r r ace adjacent to the st r e a m c h a n n e l . Sl o p e : Mi n : 7 6 % M a x : 1 1 0 % M e a n : 9 8 % S t a n d a r d D e v i a t i o n : 1 3 n = 9 El e v a t i o n : Mi n : 3 2 0 ' M a x : 7 2 0 ' M e a n : 4 3 1 ' S t a n d a r d D e v i a t i o n : 10 8 n = 9 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e To t a l A r e a : 33 . 8 5 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n MW M U 2 i s 2 6 . 7 8 a c r e s . Mi n : 0 . 4 1 a c . M a x : 1 1 . 7 7 a c . M e a n : 2 . 9 8 a c . S t a n d a r d De v i a t i o n : 3 . 3 0 a c . n = 9 MW P r o c e s s e s : Do m i n a n t l y s h a l l o w r a p i d l a n d s l i d e s ( 9 / 9 ) . Se e F o r m A 1 & A - 3 . Fo r e s t P r a c t i c e S e n s i t i v i t y : Hi g h . 10 0 % ( 9 / 9 ) o f i n v e n t o r i e d l a n d s l i d e s w e r e a s s o c i a t e d w i t h f o r e s t p r a c t i c e l a n d u s e s . MW P o t e n t i a l : Hi g h . Ob s e r v e d l a n d s l i d e r a t e o f 0 . 3 9 l a n d s l i d e s / y e a r b e t we e n 1 9 7 5 - 1 9 9 8 . De l i v e r y P o t e n t i a l : Hi g h . 1 0 0 % o f i n v e n t o r i e d l a n d s l i d e s d e l i v e r t o s t r e am c h a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Hi g h Tr i g g e r M e c h a n i s m ( s ) : H i s t o r i c a l c l e a r - c u t t i n g ( e v e n a g e t i m b e r m a n a g e m e nt ) o f s l o p e s b e t w e e n 7 6 % a n d 1 1 0 % re d u c e s t h e e f f e c t i v e s o i l c o h e s i o n c o n t r i b u t e d b y tr e e r o o t s t r e n g t h o n h i l l s l o p e s i n c l o s e p r o x i m i t y to stream ch a n n e l s . T h e l o s s o f e f f e c t i v e s o i l c o h e s i o n i n c r e as e s t h e l i k e l i h o o d o f s h a l l o w r a p i d h i l l s l o p e f a i l ure and resulting de b r i s f l o w d e p o s i t i o n o f w a t e r , w o o d a n d s e d i m e n t in t o s t r e a m c h a n n e l s . Si d e c a s t r o a d c o n s t r u c t i o n i n c o r p o r a t i n g l o g c r i b s to s u p p o r t f i l l s l o p e s o n s t e e p g l a c i a l t e r r a c e d e p o sits, has triggered sh a l l o w r a p i d l a n d s l i d e s . I n a d e q u a t e r o a d d r a i n a g e (l a c k o f c u l v e r t s , u n d e r s i z e d , a n d u n - m a i n t a i n e d c u lverts, has co n t r i b u t e d t o t h e s e e v e n t s . C o n c e n t r a t i n g r o a d d r a in a g e o n t o n o n - c o h e s i v e s o i l s i n c r e a s e s t h e l i k e l i h ood of channel er o s i o n a n d a s s o c i a t e d s t r e a m b a n k f a i l u r e s . Co n f i d e n c e : Hi g h FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 6 : Ma i n s t e m D e e p S e a t e d De s c r i p t i o n : De e p s e a t e d l a n d s l i d e s a s s o c i a t e d w i t h g l a c i a l a n d al l u v i a l t e r r a c e s a d j a c e n t t o t h e m a i n s t e m a n d S o u t h Fork Hoh Ri v e r . G l a c i a l c l a y l a y e r s t y p i c a l l y f o r m t h e l o w er s l i p s u r f a c e f o r t h e s e l o w a n g l e b l o c k - g l i d e t y p e failures. See Map A- 2 . Ma t e r i a l s : Pa r e n t m a t e r i a l s a r e c o m p o s e d o f d e p o s i t s o f O l y m p i c a l p i n e g l a c i e r s i n c l u d i n g m o r a i n e s a n d s t r a t i f i e d deposits (sand, gr a v e l , s i l t , c l a y ) . I n c l u d e s h i g h r i v e r t e r r a c e s a lo n g m a j o r r i v e r c h a n n e l s t h a t m a y n o t b e d i r e c t l y associated with gl a c i a t i o n . R e l a t i v e l y t h i c k , n o n - c o h e s i v e s o i l s ( >6 0 i n c h e s ) o v e r l i e v a r i a b l y c o n s o l i d a t e d g l a c i a l deposits and consist of v e r y c o a r s e t o v e r y f i n e g r a v e l l y s a n d y l o a m (0 - 1 5 % g r e a t e r t h a n 3 i n c h e s d i a m e t e r , 8 5 - 1 0 0 % l e s s than 2.0 mm di a m e t e r ) . La n d f o r m : Ge n e r a l l y p l a n a r t o m o d e r a t e l y c o n c a v e t e r r a c e m a r g in s a d j a c e n t t o t h e m a i n s t e m H o h a n d S o u t h F o r k r i v er channels. In s o m e a r e a s l a t e r a l m i g r a t i o n o f r i v e r c h a n n e l s h as u n d e r c u t a n d e f f e c t i v e l y o v e r s t e e p e n e d t h e t e r r ace adjacent to the st r e a m c h a n n e l . Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Sl o p e : Mi n : 2 5 % M a x : 7 5 % M e a n : 5 2 % S t a n d a r d D e v i a t i o n : 1 6 n = 1 3 El e v a t i o n : Mi n : 2 8 0 ' M a x : 7 6 0 ' M e a n : 6 0 3 ' S t a n d a r d D e v i a t i o n : 15 0 n = 1 3 To t a l A r e a : 12 6 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n M W MU 2 i s 7 6 . 6 8 a c r e s . Mi n : 0 . 2 9 a c . M a x : 2 6 . 5 2 a c . M e a n : 5 . 9 0 a c . S t a n d a r d De v i a t i o n : 6 . 7 4 . n = 1 3 MW P r o c e s s e s : De e p - s e a t e d . Se e F o r m A 1 & A - 3 . Fo r e s t P r a c t i c e S e n s i t i v i t y : Mo d e r a t e . 54 % ( 7 / 1 3 ) o f i n v e n t o r i e d l a n d s l i d e s w e r e a s s o c i a t e d w i t h f o r e s t p r a c t i c e l a n d u s e s . MW P o t e n t i a l : Mo d e r a t e . Ob s e r v e d l a n d s l i d e r a t e o f 0 . 5 7 l a n d s l i d e s / y e a r b e t we e n 1 9 7 5 - 1 9 9 8 . De l i v e r y P o t e n t i a l : Hi g h . 8 6 % o f i n v e n t o r i e d l a n d s l i d e s d e l i v e r t o s t r e a mc h a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Mo d e r a t e Tr i g g e r M e c h a n i s m ( s ) : L a t e r a l m i g r a t i o n o f m a i n s t e m r i v e r c h a n n e l s i s t h e p r i m a r y t r i g g e r f o r t h e s e m a s s w a s t i n g fe a t u r e s . E v e n a g e t i m b e r m a n a g e m e n t , r o a d c o n s t r u c ti o n a n d r o a d r u n o f f h a v e c o n t r i b u t e d t o t h e m o v e m e nt of these fe a t u r e s o v e r t i m e . Co n f i d e n c e : Mo d e r a t e FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 7 : De e p S e a t e d L a n d s l i d e s I n v e n t o r i e d b y G e r s t e l , 1 9 9 9 . De s c r i p t i o n : La r g e p e r s i s t e n t D e e p s e a t e d l a n d s l i d e s a s s o c i a t e d wi t h b o t h o l d e r s e d i m e n t a r y r o c k s o f t h e W e s t e r n O l ympic Lithic As s e m b l a g e ( t u r b i d i t e s a n d s t o n e s a n d a r g i l l i t e ) a n d a v a r i e t y o f g l a c i a l m a t e r i a l s d i s t r i b u t e d t h r o u h o ut the Middle Hoh WA U i n c l u d i n g y o u n g e r g l a c i o - l a c u s t r i n e a n d t i l l d e po s i t s . S e e G e r s t e l , 1 9 9 9 F o r m A - 1 a n d M a p A - 1 a n d A-2. Ma t e r i a l s : Se e F o r m A - 1 f o r M W M U 7 c o m m e n t s s e c t i o n r e g a r d i n g l an d s l i d e m a t e r i a l s . La n d f o r m : Ty p i c a l l y c o n v e r g e n t a n d p l a n a r v a l l e y s i d e s l o p e s or c o n v e r g e n t h e a d w a t e r h i l l s l o p e s . Sl o p e : Mi n : 6 o M a x : 2 7 o M e a n : 1 6 o S t a n d a r d D e v i a t i o n : 6 n = 3 1 El e v a t i o n : Mi n : 4 0 0 ' M a x : 2 8 8 0 ' M e a n : 1 3 8 2 ' S t a n d a r d D e v i a t i o n : 7 5 7 n = 3 1 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e To t a l A r e a : 16 3 1 . 4 3 a c r e s . T o t a l a r e a o c c u p i e d b y l a n d s l i d e s i n M W M U 2 i s 1 6 2 2 . 3 a c r e s . Mi n : 3 . 6 a c . M a x : 3 4 3 . 4 0 a c . M e a n : 5 2 . 3 3 a c . S t a n d a r d D e v i a t i o n : 7 4 . 1 0 . n = 3 1 MW P r o c e s s e s : De e p - s e a t e d . Se e F o r m A 1 & A - 3 . Fo r e s t P r a c t i c e S e n s i t i v i t y : Va r i a b l e . MW P o t e n t i a l : Va r i a b l e De l i v e r y P o t e n t i a l : Hi g h . 9 4 % o f i n v e n t o r i e d l a n d s l i d e s d e l i v e r t o s t r e am c h a n n e l s . De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Va r i a b l e . Tr i g g e r M e c h a n i s m ( s ) : S e e G e r s t e l 1 9 9 9 . Co n f i d e n c e : Hi g h a s t o l o c a t i o n . L o w a s t o b e h a v i o r o f l a n d s l i d es r e l a t e d t o f o r e s t p r a c t i c e a c t i v i t i e s . FO R M A - 2 M a s s W a s t i n g M a p U n i t D e s c r i p t i o n MW M U 8 : Lo w H a z a r d A r e a s De s c r i p t i o n : Lo w g r a d i e n t a r e a s o f i n t e r m e d i a t e r i d g e t o p s , v a l l ey s i d e w a l l s a n d v a l l e y f l o o r s . Ma t e r i a l s : Pr e d o m i n a n t l y O l y m p i c a l p i n e g l a c i a l d e p o s i t s a n d a ll u v i u m , mi n o r a r e a s o f W e s t e r n a n d H o h L i t h i c a s s e m b l a g e ro c k s o n i n t e r m e d i a t e r i d g e s a n d v a l l e y s i d e w a l l s . La n d f o r m : Lo w g r a d i e n t i n t e r m e d i a t e r i d g e s , v a l l e y s i d e w a l l s an d v a l l e y f l o o r s . Sl o p e : 0 -50 % wi t h m i n o r i n c l u s i o n s o f s t e e p e r (1 0 0 % ) sl o p e s . El e v a t i o n : 2 8 0 ' - 2 8 0 0 ' To t a l A r e a : 36 6 5 1 . 7 2 a c r e s . MW P r o c e s s e s : L i m i t e d s m a l l , s h a l l o w r a p i d l a n d s l i d e s . Se e F o r m A 1 & A - 3 . Fo r e s t P r a c t i c e S e n s i t i v i t y : Lo w MW P o t e n t i a l : Lo w De l i v e r y P o t e n t i a l : Lo w Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e De l i v e r y C r i t e r i a U s e d : Pr o x i m i t y t o f l o w i n g w a t e r / o b s e r v e d f r e q u e n c y . Ha z a r d P o t e n t i a l R a t i n g : Lo w Tr i g g e r M e c h a n i s m ( s ) : B a c k g r o u n d m a s s w a s t i n g p r o c e s s e s , h i g h i n t e n s i t y ra i n f a l l , s o i l a c c u m u l a t i o n a n d n a t u r a l di s t u r b a n c e . Co n f i d e n c e : Hi g h Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : A l l M W M U ’ s Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s 23 8 2 11 251 Cl e a r C u t 20 - 5 0 Y e a r s 15 42 6 137 200 Pa r t i a l C u t Ro a d 81 1 57 139 St r e a m C r o s s i n g La n d i n g 5 16 21 Ot h e r F o r e s t Pr a c t i c e s 2 2 Wi l d f i r e Ma t u r e F o r e s t 99 12 15 8 134 No n - F o r e s t La n d U s e To t a l s 44 0 57 21 229 747 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 1 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s 19 5 6 201 Cl e a r C u t 20 - 5 0 Y e a r s 3 3 135 141 Pa r t i a l C u t Ro a d 68 50 118 St r e a m C r o s s i n g La n d i n g 4 15 19 Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 83 8 11 8 110 No n - F o r e s t La n d U s e To t a l s 35 0 11 14 214 589 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 2 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s 12 1 5 18 Cl e a r C u t 20 - 5 0 Y e a r s 14 2 16 Pa r t i a l C u t Ro a d 3 7 10 St r e a m C r o s s i n g La n d i n g 1 1 Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 6 6 No n - F o r e s t La n d U s e To t a l s 35 1 15 51 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 3 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S po r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s Cl e a r C u t 20 - 5 0 Y e a r s 4 4 Pa r t i a l C u t Ro a d St r e a m C r o s s i n g La n d i n g Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 2 2 No n - F o r e s t La n d U s e To t a l s 6 6 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 4 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s 30 1 31 Cl e a r C u t 20 - 5 0 Y e a r s 3 3 Pa r t i a l C u t Ro a d 7 1 8 St r e a m C r o s s i n g La n d i n g 1 1 Ot h e r F o r e s t Pr a c t i c e s 2 2 Wi l d f i r e Ma t u r e F o r e s t 2 2 No n - F o r e s t La n d U s e To t a l s 42 2 3 47 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 5 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s 1 1 Cl e a r C u t 20 - 5 0 Y e a r s Pa r t i a l C u t Ro a d 1 1 St r e a m C r o s s i n g La n d i n g Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 7 7 No n - F o r e s t La n d U s e To t a l s 9 9 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 6 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s Cl e a r C u t 20 - 5 0 Y e a r s 1 4 5 Pa r t i a l C u t Ro a d 2 2 St r e a m C r o s s i n g La n d i n g Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 2 4 6 No n - F o r e s t La n d U s e To t a l s 3 6 4 13 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 7 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s Cl e a r C u t 20 - 5 0 Y e a r s 31 31 Pa r t i a l C u t Ro a d St r e a m C r o s s i n g La n d i n g Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t No n - F o r e s t La n d U s e To t a l s 31 31 Fo r m A - 3 M a s s W a s t i n g S u m m a r y T a b l e : M W M U # 8 Fi n a l D r a f t R e p o r t : 4 - 1 - 2 0 0 0 M a s s W a s t i n g M o d u l e Ac t i v i t y Sh a l l o w R a p i d La n d s l i d e La r g e P e r s i s t e n t De e p S e a t e d Fa i l u r e s Sm a l l S p o r a d i c De e p S e a t e d Fa i l u r e s De b r i s F l o w Totals Cl e a r C u t 0- 2 0 Y e a r s Cl e a r C u t 20 - 5 0 Y e a r s Pa r t i a l C u t Ro a d St r e a m C r o s s i n g La n d i n g Ot h e r F o r e s t Pr a c t i c e s Wi l d f i r e Ma t u r e F o r e s t 1 1 No n - F o r e s t La n d U s e To t a l s 1 1 8. 3 M a p s A - 1 , A - 2