Volume 1 • Landscape Assessment Technical Report Page i LANDSCAPE ASSESSMENT, UPPER SOUTH PLATTE WATERSHED Technical Report Page i LANDSCAPE ASSESSMENT, UPPER SOUTH PLATTE WATERSHED Con tents Volume 1– Landscape Assessment Introduction................................................................................................................................... 1 Step 1. Characterization of the Watershed................................................................................. 3 Management Plans and Regulatory Constraints.................................................................................... 8 Step 2. Issues and Key Questions .............................................................................................. 10 Issue A. Landscape Pattern of Vegetation................................................................................ 11 Step 3. Current Condition ................................................................................................................... 12 Variation in Vegetation Structure and Composition ...................................................................................12 Disturbance Processes and the Current Condition ......................................................................................16 Fire Hazard Patterns ....................................................................................................................................17 Risk of Catastrophic Disturbance ................................................................................................................18 Existing Distribution of Invasive Plants......................................................................................................19 Existing Terrestrial Species, Sensitive Vegetation and Wildlife.................................................................20 Step 4. Reference Condition................................................................................................................ 24 Pre-European Disturbance Processes and Patterns......................................................................................24 Step 5. Synthesis ................................................................................................................................. 26 Differences Between Existing and Historical Conditions ...........................................................................26 Habitat for Terrestrial Wildlife....................................................................................................................28 Issue B. Soil Development and Movement................................................................................ 30 Step 3. Current Condition ................................................................................................................... 31 Step 4. Reference Condition................................................................................................................ 33 Step 5. Synthesis ................................................................................................................................. 36 Issue C. Water Quality and Quantity and Aquatic Habitat ................................................... 39 Step 3. Current Condition ................................................................................................................... 40 Introduction .................................................................................................................................................40 Channel Dynamic Equilibrium....................................................................................................................40 Critical Sediment Sources and Water Quality.............................................................................................42 Existing Water Quality ................................................................................................................................45 Aquatic Habitat............................................................................................................................................46 Limiting Factors for Sediment Transport ....................................................................................................47 Step 4. Reference Conditions.............................................................................................................. 48 Pre-European Sediment Yield, Transport and Deposition ..........................................................................48 Pre-European Aquatic Habitat and Fish Populations ..................................................................................48 Step 5. Synthesis Questions for Water Quality, Quantity and Aquatic Habitat.................................. 49 Landscape Synthesis ................................................................................................................... 52 Synthesis of Issue A ............................................................................................................................ 52 Synthesis of Issue B ............................................................................................................................ 52 Synthesis of Issue C ............................................................................................................................ 52 Landscape Recommendations ................................................................................................... 62 Watershed Targets............................................................................................................................... 62 Technical Report Page ii LANDSCAPE ASSESSMENT, UPPER SOUTH PLATTE WATERSHED Landscape Considerations................................................................................................................... 62 Restoration Activities.......................................................................................................................... 63 Hydrology and Soils Recommendations............................................................................................. 65 Wildlife Recommendations................................................................................................................. 65 Plants ................................................................................................................................................... 65 Secondary Considerations................................................................................................................... 65 References.................................................................................................................................... 66 List of Preparers and Contributors........................................................................................... 70 Exhibits Exhibit 1. Colorado Location Map ........................................................................................................... 3 Exhibit 2. Project Location Map............................................................................................................... 4 Exhibit 3. Aerial View of the Mosaic Forest Condition at Cheesman Lake............................................. 5 Exhibit 4. Buffalo Park circa 1900 and 1999............................................................................................ 6 Exhibit 5. Deckers circa 1900 and 1999 ................................................................................................... 7 Exhibit 6. Management Areas and direction in the Assessment Area...................................................... 9 Exhibit 7. Vegetation Types in the Assessment Area............................................................................. 13 Exhibit 8. Selected Crown Closure Classes by Watershed..................................................................... 14 Exhibit 9. Fire Hazard Class for the Assessment Area Watersheds ....................................................... 18 Exhibit 10. Noxious Weeds of Concern in the Assessment Area............................................................. 19 Exhibit 11. Target Species ........................................................................................................................ 22 Exhibit 12. Degree of Departure of the Existing Condition from the Reference Condition .................... 27 Exhibit 13. Population Trends from Current to Reference Conditions in Assessment Area.................... 29 Exhibit 14. Risk by Watershed for Sustaining Long-Term Health and Natural Disturbance................... 38 Exhibit 15. Erosion Rating Breakdown by Watershed ............................................................................. 42 Exhibit 16. Sediment/Water Trends–Station Name: Buffalo Creek at Mouth at Buffalo Creek.............. 44 Exhibit 17. Watershed Restoration Priority.............................................................................................. 50 Exhibit 18. Conceptual Fish Population Sensitivity to Disturbances ....................................................... 51 Exhibit 19. Overall Watershed Restoration Ranking................................................................................ 53 Exhibit 20. Issue A Synthesis ................................................................................................................... 54 Exhibit 21. Issue B Synthesis.....................................................................Error! Bookmark