Appendix A Slope Stability Assessment Sharps Creek Landslide Inventory and Slope Stability Assessment The landslide history of Sharps Creek was developed using a series of 1:24000 air photographs to identify observable landslide features (primarily debris slides) in a time sequence. Due to the mixed ownership, the photo record includes Umpqua Forest coverage as well as Eugene BLM photos. Three flight years were evaluated to develop an understanding of the historical landslide occurrence, relative to disturbance in Sharps Creek. The 1946 photos were used for historic perspective on the National Forest, however 1950 photos were the earliest available for the BLM. The period of early management activity was observed using the 1966 flight for the forest and 1968 for the BLM. The third series included 1988 forest coverage and 1990 photos for the BLM. While it is well accepted that landslide analysis using air photos without field verification has limited applicability, it does provide a broad scale understanding of the frequency and magnitude of landslides, particularly shallow rapid ones. During the interpretation phase, an attempt was made to identify the type or associated disturbance with each feature. Each landslide was assigned an attribute, either natural, timber or road, based on proximal location to observable characteristics. In addition to the development of a comprehensive landslide layer in a GIS format, an attempt was made to incorporate a modeling approach to predict potential mass wasting hazards. In cooperation with the Eugene District of the BLM, in particular Barry Williams, we utilized a cohesionless, infinite slope stability model developed by Montgomery and Deitrich (1994) to portray areas subject to mass wasting potential. This was the first application of the model on Western Cascade geomorphic terrain, specifically on the Umpqua National Forest. The application of the model was tested using two data sets of digital elevation data, 30 meter and 10 meter intervals. From an initial review of these products, relative to the air photo landslide product, it appears that the resolution of the 30 meter DED’s more accurately represents the relationship of landslide features to high potential instability. One explanation of the limitations of the model may be the ability to accurately manuscript landslide features in a digital manner. Unfortunately, the inability to run the model or to generate reports without the assistance of the BLM and their UNIX system, limits the applicability of the model. Recent conversations with Dr. Dietrich indicate that an updated version of the model will be available by the end of 1999 and may be useful for project planning and future forest planning analysis. As a result of this evaluation, this information should be used with a number of caveats: · It is strictly for natural occurring shallow landslides, not deep seated failures. · All areas have topographically identical risk of landsliding. · At any given time, only a small proportion of the landslide sites will show evidence of landsliding at any one time. · Model failure typically occurs when the digital elevation data does not accurately indicate topography. · Management related failures may occur in sites classified as low potential. Reference: Montgomery, D.R. and W.E. Dietrich. 1994. A physically based model for the topographic control of shallow landsliding. Water Resources Research 30: 1153-71. Sharps Creek Watershed Analysis Appendix A-1 Appendix B Hydrology and Water Quality Summer 1996 Sharps Creek Streamflows measurements 9/10/96 to 10/1/97 two summers Stream Name Stream Name Stream Name Stream Name Date cfs mi2 cfs/mi2 Row cfs %Row 9-10-96 cfs 9-10-96 cfs/mi2 9-10-96 final estimates Sharps @ mouth 9/26/97 13.8 66.44 0.21 52 2.74 5.04 0.08 Sharps @ Staples Bridge (flow est same as 9-30--96) 10/1/97 11.9 47.3 0.25 47 2.47 4.81 0.10 Walker Cr 9/26/97 1.33 5 0.27 52 2.74 0.49 0.10 White Cr 9/25/96 0.07 1.23 0.05 28 1.47 0.04 0.04 Sharps abv White 10/1/96 5.67 30.43 0.19 23 1.21 4.68 0.15 Sharps abv Martin est 10/1/96 4.08 12.73 0.32 23 1.21 3.37 0.26 Sailors Gulch 9/25/96 0.10 0.67 0.15 28 1.47 0.07 0.10 Fairview Cr 10/1/96 1.64 5.65 0.29 23 1.21 1.35 0.24 Walton Cr 10/1/96 0.35 1.22 0.28 23 1.21 0.29 0.23 Cinge Cr 10/1/96 0.83 1.63 0.51 23 1.21 0.68 0.42 Bohemia Cr 10/3/96 0.80 2.3 0.35 23 1.21 0.66 0.29 Glenwood Cr 10/3/96 0.42 1 0.42 23 1.21 0.34 0.34 Martin abv Sharps (calculated) 9/10/96 1.59 17.7 0.09 19 1.00 1.59 0.09 Martin abv Sharps (measured) 9/29/97 3.78 17.7 0.21 50 2.63 1.44 0.08 Quartz cr 9/11/96 0.26 4.45 0.06 19 1.00 0.26 0.06 Puddin Rock 9/20/96 0.08 1.46 0.05 42 2.21 0.04 0.02 Cedar Cr 9/19/96 0.267 1.34 0.20 47 2.47 0.11 0.08 China Cr 9/17/96 0.30 2.46 0.12 144 7.58 0.04 0.02 Saddle Camp 9/23/96 0.30 1.2 0.25 31 1.63 0.18 0.15 Sharps Creek Watershed Analysis Appendix B-1 Sharps below Walker Creek 80 75 70 65 Basin Standard 64° Basin Standard 64° 60 55 TEMPERATURE (F) 50 45 40 35 30 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 9/ 9/ 9/ 9/ 9/ 01 04 07 10 13 16 19 22 25 28 01 04 07 10 13 16 19 22 25 28 31 03 06 09 12 15 18 21 24 27 30 02 05 08 11 14 Appendix B-2 Sharps Creek Watershed Analysis Martin at the mouth 80 75 70 65 Basin Standard 64° Basin Standard 64° 60 55 TEMPERATURE (F) 50 45 40 35 30 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 9/ 9/ 9/ 9/ 9/ 01 04 07 10 13 16 19 22 25 28 01 04 07 10 13 16 19 22 25 28 31 03 06 09 12 15 18 21 24 27 30 02 05 08 11 14 Sharps Creek Watershed Analysis Appendix B-3 Sharps above Martin 80 75 70 65 Basin Standard 64° Basin Standard 64° 60 55 TEMPERATURE (F) 50 45 40 35 30 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 9/ 9/ 9/ 9/ 9/ 01 04 07 10 13 16 19 22 25 28 01 04 07 10 13 16 19 22 25 28 31 03 06 09 12 15 18 21 24 27 30 02 05 08 11 14 Appendix B-4 Sharps Creek Watershed Analysis China Creek below Saddle Camp Creek 80 75 70 65 Basin Standard 64° Basin Standard 64° 60 55 TEMPERATURE (F) 50 45 40 35 30 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 6/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 7/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 8/ 9/ 9/ 9/ 9/ 9/ 01 04 07 10 13 16 19 22 25 28 01 04 07 10 13 16 19 22 25 28 31 03 06 09 12 15 18 21 24 27 30 02 05 08 11 14 Sharps Creek Watershed Analysis Appendix B-5 Appendix B-6 Sharps Creek Watershed Analysis Sharps Creek Watershed August 10, 1996 Water Temperatures 80 Row at Quarry 75 Sharps Sharps abv Pony Bridge Tributary Mouth abv Damewood abv East Tributary 70 Damewood Martin blw Walker Mouth Martin abv Clark 65 China blw Martin abv Martin abv Saddle Clark Puddin R Camp East Trib China abv Martin Fairview 60 abv Fairview Cedar Water Temperature degrees Fahrenheit China abv 23 Puddin China abv 2358 55 Rock 50 0 2 4 6 8 10 12 14 16 River Mile Sharps Creek Watershed Analysis Appendix B-7 October 3, 1997 Jim Wieman District Ranger Cottage Grove Ranger District Umpqua National Forest Dear Jim, On September 29, 1997 I looked at a bedrock reach of Layng Creek about ½ mile downstream from the Layng Creek municipal water intake and Rujada Campground, about 100 feet downstream from a concrete bridge where you described algae growing on the stream bottom. Debra Gray, hydrologic technician, and I used a Hydrolab multiprobe water quality meter to measure water temperature, dissolved oxygen (and percent oxygen saturation), pH, and specific conductivity. These parameters might be affected by algae, or indicate the sensitivity of water quality to the oxygen and carbon dioxide production and use by algae. My observations were that this reach has moderate amounts of a brown, cottony attached algae (periphyton), and longer, green filamentous algae. There was also some green moss on the rocks.