Common use of Tidegate and Floodgate Maintenance Species Impact Analysis Clause in Contracts

Tidegate and Floodgate Maintenance Species Impact Analysis. The potential effects to fish from tidegate and floodgate maintenance increases with the degree to which the watercourse or shoreline is disturbed, and the degree to which motorized equipment is used to complete the maintenance. Minor repairs have a very low potential to impact fish, whereas major repairs or replacement tend to have increasingly greater potential to impact fish. The potential for fish to be impacted by tidegate and floodgate maintenance is also related to the size of fish. Larger fish are stronger swimmers and therefore better able to escape and avoid the potential impacts of maintenance activities, whereas smaller fish are weaker swimmers and therefore at greater risk of being killed or injured. The potential for fish to be impacted is greater in those habitats where small fish rear and seek refuge. The habitats typically associated with tidegates and floodgates in the Skagit delta and estuary provide optimal rearing and refuge habitat for smaller fish, whereas larger fish tend to seek optimal rearing and refuge conditions in deeper water and offshore habitats. The potential for fish to be impacted is also dependent upon small fish being present at the tidegate or floodgate sites. For many fish species, dependence on delta and estuary habitats is seasonal. The time of the year when juvenile fish utilize the delta and estuary habitats for rearing and refuge is different for different fish species and life histories. For salmonid species, small juveniles typically depend on the Skagit delta and estuary habitats between February 1 and July 31 during which time they are at greatest risk of being impacted by tidegate and floodgate maintenance. Tidegate and floodgate maintenance activities can result in direct and indirect impacts to fish. Direct impacts include physical and/or chemical trauma to the fish that can result in injury or death. Indirect impacts are temporary and do not directly kill or injure the fish. Indirect maintenance impacts disturb and/or alter the watercourse and shoreline habitats upon which fish depend for rearing and refuge thus compromising their rearing ability and their potential to survive. The following maintenance conditions could result in direct fish impacts:  Whenever a watercourse is excavated with motorized equipment, fish can be killed or injured. Fish can be physically removed from the watercourse in the bucket of the excavator and discarded on the shoreline. The excavator bucket can also physically injure fish.  Fish can be chemically injured or killed through the inadvertent discharge of concrete leachate, or hydraulic fluid, gas, diesel oil into the watercourse from the motorized equipment used to conduct the maintenance. The following maintenance conditions could result in indirect fish impacts:  Excavation of the watercourse can result in the temporary loss of aquatic vegetation that provides fish refuge and cover habitat by physically removing the aquatic vegetation from the watercourse.  Removing the aquatic vegetation from the watercourse can temporarily reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse and temporarily reduce the light available for photosynthesis thus reducing the production of aquatic vegetation.  Excavating the watercourse can remove or bury epibenthic and benthic invertebrates that are important fish prey.  Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse such the available oxygen in the watercourse is decreased to levels that can stress, displace or kill fish.  Removing riparian vegetation that provides shade to a watercourse can elevate the water temperature and can stress, displace or kill fish.  Removing riparian vegetation can reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  Removing riparian vegetation can reduce the availability of terrestrial insects that are important fish prey. Terrestrial species impacts may include disturbance from noise generating activities. Other direct or indirect impacts are not anticipated to occur to birds. Indirect impacts to killer whales may result if their prey base is affected by the proposed actions. The following BMPs are a means to avoid and minimize impacts, as described above in Part 4.2, to fish and terrestrial species, and their habitats.

Tidegate and Floodgate Maintenance Species Impact Analysis. The potential effects for fish to fish be impacted from tidegate and floodgate maintenance increases with the degree to which the watercourse or shoreline is disturbed, and the degree to which motorized equipment is used to complete the maintenance. Minor repairs have a very low potential to impact fish, whereas major repairs or replacement tend to have increasingly greater potential to impact fish. The potential for fish to be impacted by tidegate and floodgate maintenance is also related to the size of fish. Larger fish are stronger swimmers and therefore better able to escape and avoid the potential impacts of maintenance activities, whereas smaller fish are weaker swimmers and therefore at greater risk of being killed or injured. The potential for fish to be impacted is greater in those habitats where small fish rear and seek refuge. The habitats typically associated with tidegates and floodgates in the Skagit delta and estuary provide optimal rearing and refuge habitat for smaller fish, whereas larger fish tend to seek optimal rearing and refuge conditions in deeper water and offshore habitats. The potential for fish to be impacted is also dependent upon small fish being present at the tidegate or floodgate sites. For many fish species, dependence on delta and estuary habitats is seasonal. The time of the year when juvenile fish utilize the delta and estuary habitats for rearing and refuge is different for different fish species and life histories. For salmonid species, small juveniles typically depend on the Skagit delta and estuary habitats between February 1 and July 31 during which time they are at greatest risk of being impacted by tidegate and floodgate maintenance. Tidegate and floodgate maintenance activities can result in direct and indirect impacts to fish. Direct impacts include physical and/or chemical trauma to the fish that can result in injury or death. Indirect impacts are temporary and do not directly kill or injure the fish. Indirect maintenance impacts disturb and/or alter the watercourse and shoreline habitats upon which fish depend for rearing and refuge thus compromising their rearing ability and their potential to survive. The following maintenance conditions could result in direct fish maintenance impacts:  • Whenever a watercourse is excavated with motorized equipment, fish can be killed or injured. Fish can be physically removed from the watercourse in the bucket of the excavator and discarded on the shoreline. The excavator bucket can also physically injure fish.  • Fish can be chemically injured or killed through the inadvertent discharge of concrete leachate, or hydraulic fluid, gas, diesel oil into the watercourse from the motorized equipment used to conduct the maintenance. The following maintenance conditions could result in indirect fish maintenance impacts:  • Excavation of the watercourse can result in the temporary loss of aquatic vegetation that provides fish refuge and cover habitat by physically removing the aquatic vegetation from the watercourse.  • Removing the aquatic vegetation from the watercourse can temporarily reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  • Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse and temporarily reduce the light available for photosynthesis thus reducing the production of aquatic vegetation.  • Excavating the watercourse can remove or bury epibenthic and benthic invertebrates that are important fish prey.  • Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse such the available oxygen in the watercourse is decreased to levels that can stress, displace or kill fish.  • Removing riparian vegetation that provides shade to a watercourse can elevate the water temperature and can stress, displace or kill fish.  • Removing riparian vegetation can reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  • Removing riparian vegetation can reduce the availability of terrestrial insects that are important fish prey. Terrestrial species impacts may include disturbance from noise generating activities. Other direct or indirect impacts are not anticipated to occur to birds. Indirect impacts to killer whales may result if their prey base is affected by the proposed actions. The following BMPs are a means to avoid and minimize impacts, as described above in Part 4.2, to fish and terrestrial species, and their habitats.

Tidegate and Floodgate Maintenance Species Impact Analysis. The potential effects to fish from tidegate and floodgate maintenance increases with the degree to which the watercourse or shoreline is disturbed, and the degree to which motorized equipment is used to complete the maintenance. Minor repairs have a very low potential to impact fish, whereas major repairs or replacement tend to have increasingly greater potential to impact fish. The potential for fish to be impacted by tidegate and floodgate maintenance is also related to the size of fish. Larger fish are stronger swimmers and therefore better able to escape and avoid the potential impacts of maintenance activities, whereas smaller fish are weaker swimmers and therefore at greater risk of being killed or injured. The potential for fish to be impacted is greater in those habitats where small fish rear and seek refuge. The habitats typically associated with tidegates and floodgates in the Skagit delta and estuary provide optimal rearing and refuge habitat for smaller fish, whereas larger fish tend to seek optimal rearing and refuge conditions in deeper water and offshore habitats. The potential for fish to be impacted is also dependent upon small fish being present at the tidegate or floodgate sites. For many fish species, dependence on delta and estuary habitats is seasonal. The time of the year when juvenile fish utilize the delta and estuary habitats for rearing and refuge is different for different fish species and life histories. For salmonid species, small juveniles typically depend on the Skagit delta and estuary habitats between February 1 and July 31 during which time they are at greatest risk of being impacted by tidegate and floodgate maintenance. Tidegate and floodgate maintenance activities can result in direct and indirect impacts to fish. Direct impacts include physical and/or chemical trauma to the fish that can result in injury or death. Indirect impacts are temporary and do not directly kill or injure the fish. Indirect maintenance impacts disturb and/or alter the watercourse and shoreline habitats upon which fish depend for rearing and refuge thus compromising their rearing ability and their potential to survive. The following maintenance conditions could result in direct fish impacts:  • Whenever a watercourse is excavated with motorized equipment, fish can be killed or injured. Fish can be physically removed from the watercourse in the bucket of the excavator and discarded on the shoreline. The excavator bucket can also physically injure fish.  • Fish can be chemically injured or killed through the inadvertent discharge of concrete leachate, or hydraulic fluid, gas, diesel oil into the watercourse from the motorized equipment used to conduct the maintenance. The following maintenance conditions could result in indirect fish impacts:  • Excavation of the watercourse can result in the temporary loss of aquatic vegetation that provides fish refuge and cover habitat by physically removing the aquatic vegetation from the watercourse.  • Removing the aquatic vegetation from the watercourse can temporarily reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  • Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse and temporarily reduce the light available for photosynthesis thus reducing the production of aquatic vegetation.  • Excavating the watercourse can remove or bury epibenthic and benthic invertebrates that are important fish prey.  • Excavating the watercourse or disturbing the shoreline can increase the suspended sediments in the watercourse such the available oxygen in the watercourse is decreased to levels that can stress, displace or kill fish.  • Removing riparian vegetation that provides shade to a watercourse can elevate the water temperature and can stress, displace or kill fish.  • Removing riparian vegetation can reduce the detritus input into the watercourse and reduces the production of important epibenthic and benthic invertebrates that are important fish prey.  • Removing riparian vegetation can reduce the availability of terrestrial insects that are important fish prey. Terrestrial species impacts may include disturbance from noise generating activities. Other direct or indirect impacts are not anticipated to occur to birds. Indirect impacts to killer whales may result if their prey base is affected by the proposed actions. The following BMPs are a means to avoid and minimize impacts, as described above in Part 4.2, to fish and terrestrial species, and their habitats.