Summary
The Study Team
List of Consultees
1 Introduction
1.1 Background to the development proposals
1.2 Aims of the study
1.3 Boundaries of the study area
1.4 Measurement units
1.5 Glossary
2 Outline of the Development Proposals
2.1 The proposals
2.2 Implications for Loch levels and River flows
2.2.1 Effects on Loch level frequencies, peaks and minima
Mean Loch Levels
Frequency distribution of Loch levels
Effects on peaks and minima
Summary
2.2.2 Effects on river flows
Increases in rainfall
Other water management affecting yields
Natural fluctuations
Seasonal changes in levels and river flows
Effects of river regulation on maintenance of minimum flows
The no-dredging scenario
3 Issues and Concerns
3.1 During dredging
3.2 Post-dredging
3.2.1 River Leven issues
3.2.2 Loch Lomond and Upper Leven issues
3.2.3 Boating
3.2.4 General recreation
3.2.5 Erosion
4 Resource Inventory
4.1 Geology
4.2 Soils
4.2.1 Soils around Loch Lomond
4.3 River Leven bed composition and structure
4.3.1 Introduction
4.3.2 Site characteristics and morphology
4.3.3 Sampling strategy
4.3.4 Assessment of gravel bed suitability for spawning
4.3.5 Analysis of granulometric data
4.3.6 Proposed dredging reach
4.3.7 Control reach
4.3.8 Possible toxicity of sediments
4.3.9 Conclusions
4.4 Climate
4.4.1 General characteristics
4.4.2 Bioclimatic sub-regions
4.4.3 Recent changes in rainfall
4.5 Water resources
4.5.1 Catchment analysis
4.5.2 Loch Lomond physical and chemical data
4.5.3 River Leven water quality
Methods
Data
4.6 Land use
4.6.1 Agriculture, forestry and industry
4.6.2 Land planning designations around Loch Lomond
4.7 Recreation
4.7.1 Informal recreation
4.7.2 Boating
Ferry services
Pleasure cruises
Hireboats
Casual boating
Changes in boating use of the Loch
4.8 Vegetation
4.8.1 Introduction
4.8.2 Woodland communities
Loch Lomond
River Leven corridor
4.8.3 Loch Lomond aquatic and marginal communities
Aquatic communities
Emergent and wetland communities
4.8.4 River Leven aquatic and riparian communities
4.9 Mammals
4.9.1 Introduction
4.9.2 Methods of survey
4.9.3 Conclusions
4.10 Birds
4.10.1 Introduction
4.10.2 Habitat assessment (River Leven)
4.10.3 Bird census data (River and Loch)
Wildfowl
Waders
4.11 Fish
4.11.1 Introduction
4.11.2 Fish populations as a resource to be conserved
Fish fauna
Sea lamprey (Petromyzon marinus)
Powan (Coregonus lavaretus)
4.11.3 The fishery resource
Introduction
The coarse fishery
The game fishery
4.11.4 Historical perspective
Spatial and temporal variation in catches
Evaluation of the salmonid fishery
The position of the Loch Lomond Angling Improvement Association
The importance of the River Leven within the Loch Lomond system
4.12 Freshwater invertebrates
4.12.1 Background
4.12.2 Sampling method
4.12.3 Site characteristics
4.12.4 Invertebrate assemblages
4.12.5 Loch Lomond invertebrates
5 Possible Effects of the Development
5.1 Effects on soils
5.2 Impacts on water resources
5.3 Possible changes in land use, recreation and boating
Land use
Recreation
Boating
5.4 Impacts on vegetation structure and composition
River Leven
Loch Lomond
5.5 Impacts on mammals and birds
5.5.1 Otters
5.5.2 Birds
5.6 Impacts on fish populations
5.6.1 Sea lamprey
5.6.2 Powan
5.6.3 Migratory salmonids
Access problems
Spawning and nursery area
5.6.4 Pike
5.6.5 General conclusions: fish
Loch levels
Discharge and water level in the River Leven
The dredging
Short term effects of dredging
Possible longer-term effects
5.7 Impacts on aquatic and terrestrial invertebrates
5.7.1 Aquatic invertebrates
5.7.2 Terrestrial invertebrates
6 Mitigating Impacts
6.1 Measures to reduce impacts on boating
6.2 Reducing effects on vegetation
6.3 Reducing impact on mammals and birds
6.4 Minimising impacts on fish and fisheries
6.4.1 Dredging
6.4.2 Fisheries
6.5 Mitigating impacts on invertebrates
6.6 The no-dredging option
7 Likely Severity of Impacts
7.1 The scoring system
7.2 Effects of dredging
7.3 The no-dredging option
7.4 Effects of increased water abstraction
8 Survey and monitoring
8.1 River bed profile and gravel composition
8.2 Water quality
8.3 Reed counting and mapping in the River Leven
8.4 Monitoring sea lampreys
8.5 Salmonid populations in the River Leven
8.6 Salmonid populations elsewhere in the Loch Lomond system
8.7 Aquatic invertebrates
9 References
Appendices