Watershed Analysis of the Sixes and New River Area Coos and Curry County, OR January, 2008 Prepared by Myrtlewood IDT Composed of: Matthew Azhocar Aimee Hoefs Dale Stewart Holly Witt Sixes-New River Watershed Analysis Page 1 of 124 Table of Contents Introduction and Purpose .................................................................................................... 6 I. WATERSHED CHARACTERAZATION..................................................................... 7 Introduction..................................................................................................................... 7 Sub-watersheds ............................................................................................................... 9 Table 1 Sixes-New River Areas.................................................................................. 9 Ecoregions..................................................................................................................... 11 Coastal Lowlands...................................................................................................... 11 Wetlands ................................................................................................................... 11 Two Mile............................................................................................................... 12 New River ............................................................................................................. 12 Sixes River............................................................................................................ 12 Sothern Oregon Coastal Mountains.......................................................................... 12 Land Ownership and Use.............................................................................................. 13 Land Ownership........................................................................................................ 13 Table 2 Land Ownership within 5th Field Watershed.............................................. 13 Land Use ................................................................................................................... 15 II. WATERSHED ISSUES............................................................................................... 17 III. HISTORIC AND CURRENT CONDITIONS .......................................................... 17 Past Use......................................................................................................................... 17 Human Settlement..................................................................................................... 17 Mining....................................................................................................................... 18 Agriculture ................................................................................................................ 18 Timber....................................................................................................................... 18 Fisheries .................................................................................................................... 19 Recreation ................................................................................................................. 19 Current Use ................................................................................................................... 19 Human Presence........................................................................................................ 19 Mining....................................................................................................................... 20 Agriculture ................................................................................................................ 20 Timber....................................................................................................................... 20 Fisheries .................................................................................................................... 20 Recreation ................................................................................................................. 21 IV. EROSIONAL PROCESSES ACROSS THE LANDSCAPE..................................... 21 Geological Influence..................................................................................................... 21 Climatic Influence......................................................................................................... 23 Sediment Delivery Mechanisms within the Watershed................................................ 23 Sediment Capture Mechanisms..................................................................................... 26 Transportation Network- Roads.................................................................................... 26 Road Condition Assessment ......................................................................................... 26 Road Risk Rating .......................................................................................................... 29 Table 3 - Roads Associated with Streams and Riparian Reserves............................ 29 V. VEGETATION AND TYPES ACROSS THE LANDSCAPE .................................. 30 General Description ...................................................................................................... 30 Special Status Species................................................................................................... 31 Table 4. Documented Special Status Plants within the Sixes-New River Watershed32 Vegetational Disturbance and Type Changes............................................................... 33 Vegetation Type Classification..................................................................................... 36 Sixes-New River Watershed Analysis Page 2 of 124 Table 5 Sixes-New River Watershed Area Vegetation Information ..................... 39 Table 6 Sixes-New River Riparian Reserve Vegetation Information.................... 40 Riparian Reserve information....................................................................................... 41 Noxious Weeds ............................................................................................................. 42 Wetlands ....................................................................................................................... 42 Table 7. The Classification System of Cowardin et al. (1979, FWS/OBS-79/31) .. 43 VI. HYDROLOGY.......................................................................................................... 45 Introduction................................................................................................................... 45 Flow .............................................................................................................................. 45 Table 8 Road Density within Subwatersheds ........................................................... 47 Channel Habitat Typing................................................................................................ 48 Sixes River................................................................................................................ 49 Floras Creek.............................................................................................................. 49 Table 9. Channel Habitat Types within Subwatersheds .......................................... 50 Water Quality................................................................................................................ 51 Temperature Discussion................................................................................................ 52 Turbidity Discussion..................................................................................................... 54 Nutrients........................................................................................................................ 56 Floras Creek.............................................................................................................. 56 Sixes River................................................................................................................ 56 VII. AQUATIC SPECIES AND HABITAT: .................................................................. 58 Habitat Distribution and Use ........................................................................................ 58 General Characterization .............................................................................................. 58 New River Frontal..................................................................................................... 58 Sixes.......................................................................................................................... 59 Fish Distribution ........................................................................................................... 59 Table 10. Fish Species Documented Within the Sixes – New River Watershed Area60 Habitat Conditions Relative to ODFW Benchmarks.................................................... 60 New River Frontal..................................................................................................... 60 Sixes.......................................................................................................................... 61 Species Life History.................................................................................................. 65 Pacific lamprey ....................................................................................................