Environmental Issues Affecting Small Hydropower Timothy Hogan
Environmental Issues Affecting Small Hydropower Timothy Hogan Senior Fisheries Biologist Alden Research Laboratory
Environmental Issues Affecting Small Hydropower Timothy Hogan Alden
ALDEN
Environmental Business Council of New England Small Hydropower in New England October 25, 2012 Solving flow problems since 1894
Outline • What Issues? • Some Basics • Impacts Defined – – – –
Upstream Passage Downstream Passage Minimum Flow Water Quality (dissolved oxygen)
• Mitigation Approaches • Tools to Aid in Mitigation/Design
ALDEN
Solving flow problems since 1894
Potential Environmental Impacts 1. Barrier to upstream and downstream passage (migration, river connectivity) 2. Fluctuations in river flow of bypass reach (habitat) 3. Water quality in tailrace (dissolved oxygen)
ALDEN
Solving flow problems since 1894
Some Basics Potential Environmental Impacts
Tailrace Impact Dissolved oxygen
Powerhouse Impact Barrier to upstream and downstream movement
ALDEN
Forebay Canal
Bypassed Reach
Dam
Impact Water quality/habitat
Impact Barrier to upstream and downstream movement
Solving flow problems since 1894
Some Basics Which species/lifestages can be impacted by hydro operation? Anadromous: Spawn and rear in freshwater, mature in marine environment
ALDEN
Catadromous: Spawn in marine environment, rear and mature in freshwater
Potamodromous: Complete entire life cycle in freshwater
Solving flow problems since 1894
Upstream and Downstream Passage Biological Impacts • Blocks or delays upstream/downstream migration of fish • Disrupts connectivity of habitat for aquatic species
Operational Impact • • • •
ALDEN
Provision of passage may be required for licensing Can be contentious, esp. if listed species present Requires construction, operation, and maintenance (i.e., $) May result in generation restrictions (i.e., $)
Solving flow problems since 1894
Upstream Passage Target species in New England
ALDEN
Solving flow problems since 1894
Upstream Passage - Mitigation Biological Considerations • • • • •
Target species Life stage Migration timing/seasonality Migration behavior (diel activity, light preferences, bottom or surface oriented) Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • • •
ALDEN
Project head Flow rate and velocity criteria Attraction flow Location relative to turbine discharge and spill Installation, maintenance, and operational issues Cost Solving flow problems since 1894
Upstream Passage - Options Fish Ladders
Fish Lifts
Pumps
Nature-like Fishways
ALDEN
Solving flow problems since 1894
Upstream Passage Example Holyoke Dam • • • • • •
1873 installed ladder; no fish passed 1940 installed another ladder; no fish passed 1951 evaluated pressure lock 1955 lift installed in tailrace 1976 lift installed in bypass reach 2004 improvements to lifts
Images from Ducheney et al. 2006
Result • •
Lift is very effective Often cited as an example of a successful fishway
ALDEN
Solving flow problems since 1894
Downstream Passage
About 5 to 30 percent of fish passing through hydro turbines are killed
ALDEN
Solving flow problems since 1894
Downstream Passage - Mitigation Biological Considerations • • • • •
Target species Life stage Migration timing/seasonality Migration behavior (diel activity, light preferences, bottom or surface oriented) Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • • •
ALDEN
Site layout Hydraulics Location relative to turbine intakes Installation, maintenance, and operational issues Debris-related impacts Cost Solving flow problems since 1894
Downstream Passage - Options Guidance Technologies
ALDEN
Physical Barriers
Turbine Passage
Solving flow problems since 1894
Downstream Passage Example Holyoke Canal •
• •
1970’s installed electroshocker and bypass pipe at Boatlock Station 1992 installed louver facility with partial-depth louvers 2002 extended louvers to fulldepth
Flow
Result • •
Louver facility is very effective Good efficiency for multiple species
Flow
ALDEN
Photo: Courtesy Chris Tomichek, Kleinschmidt Associates
Solving flow problems since 1894
Minimum Flow
ALDEN
Solving flow problems since 1894
Minimum Flow Biological Impacts •
Alterations to habitat associated with unnatural flow regimes –
• • • •
low and high flows and the rates at which flows increase and decrease
Fish migration Fish stranding Primary production Changes in water quality (e.g., temperature, DO)
Operational Impact • • •
Provision of minimum flow may be required for licensing Can be contentious, esp. if listed species present Provision of minimum flow may result in less generation
Other Impacts • •
ALDEN
Sediment transport and deposition Recreation/navigation
Solving flow problems since 1894
Minimum Flow - Mitigation Biological Considerations • • • • •
Target species Life stage Habitat requirements Migration timing/seasonality Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • •
ALDEN
Site layout Location of release Method of release Channel geometry Cost
Solving flow problems since 1894
Water Quality (DO) • Stratification of impoundment results in lower DO water near intake
From Foust and Coulson 2011
ALDEN
Solving flow problems since 1894
Water Quality (DO) - Mitigation Aeration Approaches Central
Peripheral
Distributed
All images from Foust and Coulson 2011
ALDEN
Solving flow problems since 1894
Tools to Aid in Mitigation/Design
Physical Modeling
Literature Review
ALDEN
Laboratory Studies
Field Studies
Numerical Modeling - Computational Fluid Dynamics (CFD) Solving flow problems since 1894
Conclusions • Hydropower is an important piece of the renewable energy portfolio • Environmental impacts are unavoidable • Environmental impacts can be minimized: – Technologically – Operationally
• Many tools available to develop effective mitigation approaches
ALDEN
Solving flow problems since 1894
Thanks Tim Hogan Alden [email protected] (508) 829-6000, ext. 6473
ALDEN
Solving flow problems since 1894
Environmental Issues Affecting Small Hydropower Timothy Hogan Alden
ALDEN
Environmental Business Council of New England Small Hydropower in New England October 25, 2012 Solving flow problems since 1894
Outline • What Issues? • Some Basics • Impacts Defined – – – –
Upstream Passage Downstream Passage Minimum Flow Water Quality (dissolved oxygen)
• Mitigation Approaches • Tools to Aid in Mitigation/Design
ALDEN
Solving flow problems since 1894
Potential Environmental Impacts 1. Barrier to upstream and downstream passage (migration, river connectivity) 2. Fluctuations in river flow of bypass reach (habitat) 3. Water quality in tailrace (dissolved oxygen)
ALDEN
Solving flow problems since 1894
Some Basics Potential Environmental Impacts
Tailrace Impact Dissolved oxygen
Powerhouse Impact Barrier to upstream and downstream movement
ALDEN
Forebay Canal
Bypassed Reach
Dam
Impact Water quality/habitat
Impact Barrier to upstream and downstream movement
Solving flow problems since 1894
Some Basics Which species/lifestages can be impacted by hydro operation? Anadromous: Spawn and rear in freshwater, mature in marine environment
ALDEN
Catadromous: Spawn in marine environment, rear and mature in freshwater
Potamodromous: Complete entire life cycle in freshwater
Solving flow problems since 1894
Upstream and Downstream Passage Biological Impacts • Blocks or delays upstream/downstream migration of fish • Disrupts connectivity of habitat for aquatic species
Operational Impact • • • •
ALDEN
Provision of passage may be required for licensing Can be contentious, esp. if listed species present Requires construction, operation, and maintenance (i.e., $) May result in generation restrictions (i.e., $)
Solving flow problems since 1894
Upstream Passage Target species in New England
ALDEN
Solving flow problems since 1894
Upstream Passage - Mitigation Biological Considerations • • • • •
Target species Life stage Migration timing/seasonality Migration behavior (diel activity, light preferences, bottom or surface oriented) Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • • •
ALDEN
Project head Flow rate and velocity criteria Attraction flow Location relative to turbine discharge and spill Installation, maintenance, and operational issues Cost Solving flow problems since 1894
Upstream Passage - Options Fish Ladders
Fish Lifts
Pumps
Nature-like Fishways
ALDEN
Solving flow problems since 1894
Upstream Passage Example Holyoke Dam • • • • • •
1873 installed ladder; no fish passed 1940 installed another ladder; no fish passed 1951 evaluated pressure lock 1955 lift installed in tailrace 1976 lift installed in bypass reach 2004 improvements to lifts
Images from Ducheney et al. 2006
Result • •
Lift is very effective Often cited as an example of a successful fishway
ALDEN
Solving flow problems since 1894
Downstream Passage
About 5 to 30 percent of fish passing through hydro turbines are killed
ALDEN
Solving flow problems since 1894
Downstream Passage - Mitigation Biological Considerations • • • • •
Target species Life stage Migration timing/seasonality Migration behavior (diel activity, light preferences, bottom or surface oriented) Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • • •
ALDEN
Site layout Hydraulics Location relative to turbine intakes Installation, maintenance, and operational issues Debris-related impacts Cost Solving flow problems since 1894
Downstream Passage - Options Guidance Technologies
ALDEN
Physical Barriers
Turbine Passage
Solving flow problems since 1894
Downstream Passage Example Holyoke Canal •
• •
1970’s installed electroshocker and bypass pipe at Boatlock Station 1992 installed louver facility with partial-depth louvers 2002 extended louvers to fulldepth
Flow
Result • •
Louver facility is very effective Good efficiency for multiple species
Flow
ALDEN
Photo: Courtesy Chris Tomichek, Kleinschmidt Associates
Solving flow problems since 1894
Minimum Flow
ALDEN
Solving flow problems since 1894
Minimum Flow Biological Impacts •
Alterations to habitat associated with unnatural flow regimes –
• • • •
low and high flows and the rates at which flows increase and decrease
Fish migration Fish stranding Primary production Changes in water quality (e.g., temperature, DO)
Operational Impact • • •
Provision of minimum flow may be required for licensing Can be contentious, esp. if listed species present Provision of minimum flow may result in less generation
Other Impacts • •
ALDEN
Sediment transport and deposition Recreation/navigation
Solving flow problems since 1894
Minimum Flow - Mitigation Biological Considerations • • • • •
Target species Life stage Habitat requirements Migration timing/seasonality Swimming capabilities (burst, prolonged, and sustained swimming speeds)
Engineering Considerations • • • • •
ALDEN
Site layout Location of release Method of release Channel geometry Cost
Solving flow problems since 1894
Water Quality (DO) • Stratification of impoundment results in lower DO water near intake
From Foust and Coulson 2011
ALDEN
Solving flow problems since 1894
Water Quality (DO) - Mitigation Aeration Approaches Central
Peripheral
Distributed
All images from Foust and Coulson 2011
ALDEN
Solving flow problems since 1894
Tools to Aid in Mitigation/Design
Physical Modeling
Literature Review
ALDEN
Laboratory Studies
Field Studies
Numerical Modeling - Computational Fluid Dynamics (CFD) Solving flow problems since 1894
Conclusions • Hydropower is an important piece of the renewable energy portfolio • Environmental impacts are unavoidable • Environmental impacts can be minimized: – Technologically – Operationally
• Many tools available to develop effective mitigation approaches
ALDEN
Solving flow problems since 1894
Thanks Tim Hogan Alden [email protected] (508) 829-6000, ext. 6473
ALDEN
Solving flow problems since 1894
