Watershed Analysis Report for the Upper Main Eel River Watershed
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United States United States Department of Agriculture Department of the Interior Forest Service Bureau of Land Management ULX sjSh Watershed Analysis Report for the Upper Main Eel River Watershed May 1995 TABLE OF CONTENTS 1.0 DESCRIPTION OF THE UPPER MAIN EEL WATERSHED , 1.1 Location and Geography .. .. 1 1.2 Climate 1 1.3 Geology and Soils '.'.'.'..'.. 1 1.4 Hydrology 4 1.5 Fishenes . .... .5 1.6 Plant Communities 5 1.7 Fire 5 1.8Wildlife 6 1.9Historical Context 6 1.10 Ownership, Administration, and Land Allocation ,7 1.11 People and the Watershed 9 Z0 INTRODUCTION TOWATERSHED ANALYSIS n 2.1 Background Information on Planning and Watershed Analysis !... 11 2.2 The Intent of Watershed Analysis !11 2.3 Watershed Analysis on the Mendocino National Forest "\2 2.4The Upper Main Eel Watershed Analysis ..... *\2 3.0 ISSUE 1-ANADROMOUS STOCKS AT RISK 17 3.1 Issue Statement 17 3.2 Desired Conditions 17 3.3 Key Questions 17 3.4 Past Conditions and Processes 18 3.5 Current Conditions and Processes 21 3.6 Future Trends 29 4.0 ISSUE 2-RIPARIAN ECOSYSTEM FUNCTION 33 4.1 Issue Statement 33 4.2 Desired Conditions . 33 4.3 Key Questions 33 4.4 Past Conditions and Processes 33 4.5 Current Conditions and Processes 35 4.6 Future Trends 42 5.0 ISSUE 3-THREATENED, ENDANGERED, AND SPECIALSTATUS SPECIES 45 5.1 Issue Statement 45 5.2 Desired Conditions 45 5.3 Key Questions 45 5.4 Past Conditions andProcesses 46 5.5 Current Conditions and Processes 47 5.6 Future Trends 56 6.0 ISSUE 4-PLANT COMMUNITY CHANGES 61 6.1 Issue Statement 61 6.2 Desired Conditions 61 6.3 Key Questions ; 61 6.4 Past Conditions and Processes 62 6.5 Current Conditions and Processes 68 6.6 Future Trends 76 i-1 7.0 ISSUE 5-ECONOMIC OPPORTUNITIES 79 7.1 Issue Statement 79 7.2 Desired Conditions 79 7.3 Key Questions 79 7.4 Past Conditions and Processes 80 7.5 Current Conditions and Processes 85 7.6 Future Trends 88 8.0 ISSUE 6-EROSION AND SEDIMENTATION 93 8.1 Issue Statement ' 93 8.2 Desired Conditions 93 8.3 Key Questions 93 8.4 Past Conditions and Processes ............... 93 8.5 Current Conditions and Processes ! 99 8.6 Future Trends 104 9.0 ISSUE 7-RECREATION AND EXPERIENTIAL VALUES 107 9.1 Issue Statement ... .. 107 9.2 Desired Conditions .............. 107 9.3 Key Questions ! 107 9.4 Past Conditions and Processes 108 9.5 Current Conditions and Processes ! 110 9.6 Future Trends 114 10.0 GUIDANCE FOR SITE ANALYSIS AND PROJECT-LEVEL PLANNING AND DESIGN IN THE UPPER MAIN EEL WATERSHED 119 10.1 Riparian Reserve Delineation and Project Guidance ! 119 10.2 Specific Land Categories ................. 121 10.3 Upland Silvicultural Treatments and Prescribed Fire .122 10.4 Cumulative Effects Analysis .................. 123 10.5 Considerations for Slides 123 10.6 Transportation Planning 124 10.7 Recreation-Related Project-Level Planning 12s 11.0 WATERSHED RESTORATION AND ENHANCEMENT OPPORTUNITIES 127 11.1 Projects to Directly Benefit Riparian and Aquatic Values 127 11.2 Projects to Directly Benefit Terrestrial Values ! 130 12.0 ADDITIONAL MANAGEMENT OPPORTUNITIES 133 12.1 Partnerships And Cooperative Agreements 133 12.2 Local Economic Development 137 13.0 DATA GAPS 139 13.1 Anadromous Stocks at Risk and Riparian Ecosystem Function 139 13.2 Threatened, Endangered, and Special Status Species ! 140 13.3 Plant Community Changes 142 13.4 Erosion and Sedimentation ! 143 13.5 Recreation and Experiential Values 143 14.0 MONITORING NEEDS AND WATERSHED ANALYSIS REVISION CRITERIA 145 14.1 Anadromous Stocks at Risk and Riparian Ecosystem Function 145 14.2 Threatened, Endangered, and Special Status Species 147 14.3 Plant Community Changes 148 14.4 Erosion and Sedimentation 148 14.5 Watershed Analysis Revision Criteria ' 149 i-2 15.0 INFORMATION SOURCES 15l 15.1 References Cited ^...... --, 15.2 GIS Information Sources ^o 15.3 Other Information Sources is9 16.0 APPENDICES 161 16.1 List of Watershed Analysis Team Members and Others Consulted 161 16.2 Aquatic Conservation Strategy Objectives ! 163 16.3 Answers to Questions in Appendix Cof the FY 94-96 Watershed Analysis Guidelines 164 16.4 Attacnment C ofTable C-3 Species List 173 16.5 Geology of the Upper Main Eel Watershed 177 16.6 Recreation 183 16.7 Plates (P**w!'.$^r^[Y )\ \\\\\\\\\\ \ i84 Plate 1 Hydrography Plate 2 Ownership and Administration Plate 3 Land Allocation Plate 4 Fish Bearing Streams Plate 5 Forest Vegetation Distribution Plate 6 Non-Forest Vegetation Distribution Plate 7 Interim Riparian Reserves LIST OF FIGURES 1-1 Mendocino National Forest Location Map 2 1-2Upper Main Eel Watershed Location Map 3 6-1 Frequency of fires in the Upper Main Eel watershed, 1911-1989 66 6-2 Area burned annually in 11 western states, 1916-1989 . 67 6-3 Distribution of vegetation in the Upper Main Eel watershed 68 6-4 Acres of mixed conifer by size class in the Upper Main Eel watershed 70 6-5 Acres of conifer hardwood by size class in the Upper Main Eel watershed 70 6-6 Acres of red fir by size class in the Uper Main Eel watershed 71 6-7 Acres of hardwoods by size class in the Upper Main Eel watershed 71 6-8 Volume of timberharvested from the Upper Main Eel watershed by the Upper Lake District... 83 6-9 Volume of timber harvested from the Upper Main Eel watershed by the Stonyford District ... 84 i-3 LIST OF TABLES 1-1 Ownership and area within the watershed 8 1-2 ROD land allocation types and areas within the watershed 8 5-1 Owl activity centers in LSRs. wilderness, and matrix 49 5-2 Acres of suitable nesting and roosting habitat by land allocation ... 50 5-3 Acres of suitable dispersal habitat by land allocation si 5-4 Bald eagle reproduction at Lake Pillsbury 53 6-1 Vegetation acreage by type and size class .!....... 69 6-2 Fire occurrence, 1911-1994, on the Upper Main Eel watershed, Mendocino N.F ..........73 6-3 Effectiveness of fire suppression for fires of various fire intensity .'!.'!.*'75 6-4 Proposed disturbance regimes for the Upper Main Eel Watershed ..............77 16.3-1 Acres of suitable nesting and roosting habitat by land allocation ............... 167 16.3-2 Acres of suitable dispersal habitat by land allocation 168 16.3-3 Bald eagle reproduction at Lake Pillsbury 170 16.5-1 Soil types, slopes, hazard ratings, and areas within the Upper Main Eel watershed 179 16.6-1 Construction ofcurrent Forest Service facilities at Lake Pillsbury 183 1.0 DESCRIPTION OFTHE UPPER MAIN EEL WATERSHED 1.1 Location and Geography The majority for the Upper Main Eel watershed lies within the Mendocino National Forest (the Forest), which islocated onthewestsideofthe California Coast Range approximately 25miles northeast ofUkiah. California (Figure 1-1). Most ofthe watershed (84 percent) lies in Lake County, California. The remainder is in Mendocino County (10 percent) and Glenn County (6 percent) (Figure 1-2). The watershed includes the headwaters of the Eel River downstream to the Cape Horn Dam. The eastern boundary of the watershed runs along the backbone of the California Coast Range from Bald Mountain (6,739 feet) in the north, through Snow Mountain (at 7,038 feet, the highest point in the watersned), to Goat Mountain (6,121 feet) in the south. It forms abasin of nearly 350 square miles encompassing the entire Eel River drainage above Cape Horn Dam. Cape Horn Dam (which impounds the Van Arsdale Reservoir) is located at the low point of the watershed with a spillway elevation of 1,493 ft. Above Cape Horn Dam on the Eel River, near the center of the watershed, lies another reservoir, Lake Pillsbury. which is impounded by Scott Dam (Spillway elevation 1818 ft.) Lake Pillsbury has three main'arms: the Eel River Valley and Canyon forms the eastern arm, the Rice Fork Canyon forms the deep, narrow southern arm, and Smokehouse Creek and other streams feed the broad, but shallow northern arm which inundates the lower part ofGravelly Valley. Almost 80 percent ofthe watershed analysis area drains into Lake Pillsbury withthe remainder draining into the Eel River below Scott Dam. When full, the lake covers over 3 square miles. 1.2 Climate The climate ofthe Upper Main Eel watershed is relatively moderate with occasional extreme temperatures during the winter and summer. During the summer, temperatures often exceed 100 degrees, while winter temperatures usually fall below freezing. Over 80 percent of the seasonal rainfall occurs between November 1 and April 1. Rainfall atthe upper elevations is relatively high, averaging 50-60 inches per year along the eastern boundary ofthe watershed, and 70-80 inches peryear around Bald Mountain. In the valleys, rainfall averages 40-50 inches peryear, with the lowest amounts in the vicinity of Lake Pillsbury. Snow occasionally falls at the 2,500-foot level, but seldom builds any significant snowpack below 5,000 feet. A U.S. Weather Bureau continuous-record precipitation station was operated near Lake Pillsbury from 1907 to 1936. During this 29-year period, the mean annual precipitation was 47.62 inches and the monthly precipitation ranged from 0 to 18.10 inches. The temperature range during the same period was from 15 degrees to 107 degrees F. At the present time the U.S. Weather Bureau precipitation station nearest the Upper Main Eeldrainage is located at the PotterValley powerhouse 10 miles southwest of Scott Dam at an elevation of 1,014 feet above mean sea level.