Hydrological and Biological Responses to Forest Practices (eBook)

Foreword 6
Preface 8
Contents 9
Contributors 11
The Alsea Watershed Study 13
Water Survey 14
Soil and Vegetation Survey 15
Logging-Aquatic Resources Study 16
Study Area 17
Deer Creek 19
Flynn Creek 19
Needle Branch 20
Logging Treatments 20
Methods 23
Water Resources 23
Biological Resources 24
Training and Educational Opportunities 26
Paired Watershed Studies in the United States 14
Summary 27
Literature Cited 28
Effects of Timber Harvesting on Streamflow in the Alsea Watershed Study 31
Methods 35
Precipitation 35
Streamflow 36
Results 38
Annual Runoff 38
Peak Flows 41
Three-Day High Flow Runoff 44
Storm Hydrograph Changes 45
Low Flows 45
Summary 47
Literature Cited 48
Stream Temperature and Dissolved Oxygen 49
Stream Temperature and Fish Habitat 49
Response of Stream Temperature to Forest Management in the Alsea Watershed Study 51
Discussion of Temperature Response 55
Dissolved Oxygen and Fish Habitat 58
Dissolved Oxygen Response in the Alsea Watershed 59
Literature Cited 63
Forest Practices and Sediment Production in the Alsea Watershed Study 67
Factors Affecting Sedimentation in the Oregon Coast Range 67
Study Design 69
Annual Sediment Yields 71
Sediment Concentrations 73
Discussion 76
Literature Cited 78
Salmonid Populations and Habitat 79
Methods 80
Habitat Characterization 80
Dissolved Oxygen 80
Gravel Composition 80
Permeability 81
Fish Population Statistics 81
Adult Enumeration 81
Juvenile Populations 82
Prelogging Conditions 84
Fish Populations 84
Productivity of Headwater Streams 84
Ecology of Salmonid Incubation 84
Early Juvenile Residence and Emigration 87
Determinants of Smolt Abundance 88
Post-logging Changes 90
Habitat Quality 92
Gravel Composition 92
Stream Temperature 93
Dissolved Oxygen 93
Permeability 94
Fish Populations 94
Fry Emergence 94
Emergent Survival and Gravel Quality 96
Fry Emigration 97
Juvenile Density 97
Smolt Migrations 99
Evaluation 101
Literature Cited 103
The Oregon Forest Practices Act and Forest Research 106
Origins of Oregon Forest Practice Regulation 106
Creation of the Oregon Forest Practices Act 108
Use of Research Results in Developing Forest Practice Rules 110
Rules for Watershed Protection 111
Riparian Buffer Strips 111
Dissolved Oxygen 112
Large Woody Debris 113
Pesticides 113
Sediment 114
Rule Changes in the Late 1970s and 1980s 114
Issues of the 1990s 116
2000 and Beyond 120
Literature Cited 121
The New Alsea Watershed Study 125
Literature Cited 130
Flynn Creek: Research Natural Area 132
Research Natural Areas 132
Location 133
General Description 134
Terrestrial Vegetation 135
Fish Populations 137
Terrestrial Animals 142
Mineral Deposits 142
Summary 146
Literature Cited 146
Long-term Streamflow Changes Following Timber Harvesting 148
Annual Water Yield 150
Peak Flows 151
Low Flows 153
Methodology 154
Results and Discussion 157
Annual Water Yield 157
Peak Flows 158
Low Flows 159
Low Flow Days 161
Conclusions 162
Literature Cited 163
Long-term Water Quality Changes Following Timber Harvesting 165
Methodology 167
Results and Discussion 170
Conclusions 174
Literature Cited 175
Risk Assessment for Salmon from Water Quality Changes Following Timber Harvesting 179
Problem Formulation 179
Alsea Watershed Study 180
Analysis 181
Toxicological Evaluation 181
Exposure Assessment 184
Expected Nitrate-nitrogen Concentrations 185
Risk Characterization 187
Summary 188
Literature Cited 188
Sedimentation Studies Following the Alsea Watershed Study 191
Sedimentation Research Objectives 192
Suspended Sediment Transport 193
Bedload Sediment Transport 198
Bedload Transport Sampling Methods 199
Flynn Creek Bedload Transport Rates 201
Sediment Transport - Channel Morphology Interactions 206
Streambed Scour and Fill 207
Substrate Composition 210
Channel Response to Increases in Sediment Delivery 212
Other Research Results 213
Summary 215
Literature Cited 216
Woody Debris from the Streamside Forest and its Influence on Fish Habitat 219
Connections Between Woody Debris and Fish Habitat 220
Streamside Forests and Woody Debris: Past and Present 222
Conversion to Younger Trees 224
Conversion to Alder Trees 224
Intentional Debris Removal 226
Status of Woody Debris in Managed Forest Streams 227
Trees Retained Along Streams Following Logging 228
Source Areas of Woody Debris 228
Longevity of Buffer Trees 231
Effect of Buffer Trees when they Fall 232
Managing Alder-dominated Streamside Areas 235
Direct Placement of Woody Debris 236
Rearranging Existing Woody Debris 236
Enhancing Existing Habitat Features 237
Bringing in Woody Debris from Elsewhere 237
Conclusion: Dealing with the Past and Planning for the Future 238
Literature Cited 239
Long-term Trends in Habitat and Fish Populations in the Alsea Basin 244
Methods 245
Stream Habitat Measurements 245
Salmonid Population and Biomass Estimates 246
Results 248
Stream Habitat 248
Salmonid Population and Biomass 248
Discussion 258
Literature Cited 262
The Alsea Watershed Study: A Comparison with Other Multi-year Investigations in the Pacific Northwest 265
Alsea Watershed and Forest Practices 267
Study Locations, Objectives, and Methods 268
Comparison of Study Results 272
Studies of Logging Effects 272
Studies of Supplementation 279
Studies of Habitat Enhancement 280
Other Multi-year Studies 285
Interannual Variation 287
Conclusions 291
Literature Cited 293
Watershed Management 296
The Watershed Management Approach 296
Resource Management Concepts 296
Watersheds as a Basis for Resource Management 298
Timber Harvesting 299
Harvest Systems 299
Harvest Scheduling 300
Harvest Layout and Operations 301
Forest Roads 302
Road Area and Location 302
Road Design 303
Road Construction and Maintenance 305
Other Forest Practices 305
Slash Treatment and Site Preparation 306
Reforestation, Stand Management and Other Considerations 307
Conclusions 308
Literature Cited 309
Research Opportunities in Hydrology and Biology in Future Watershed Studies 312
Literature Cited 318
Index 320