Tailwater refers to waters located immediately downstream from a hydraulic structure, such as a dam, spillway, bridge or culvert.[1] Generally measured and reported as the average water depth downstream of a hydraulic structure, tailwater can vary based on the outlet from the structure as well as downstream influences that may restrict or advance the usual flow of water from the structure. The creation of a tailwater will have significant impacts on both the abiotic and biotic conditions of the waterway.
The Colorado River tailwater below Glen Canyon Dam.
The environmental conditions in a tailwater influence the entire food web of the waterway. Consistent flows, higher temperatures, and clear water found in tailwaters create an ideal habitat for filamentous green algae.[2] The near-shore zones of tailwaters that are submerged during hydropeaking but dry during consistent flows are far less productive areas of the waterway. Most algal species are not adapted to handle this exposure to air for extended periods of time resulting in a loss of primary productivity and an increase in organic matter that gets washed away when flow increases.[2]
Macroinvertebrate impactsedit
Macroinvertebrate communities assemblages largely depend on algal composition of the waterway. With the conditions created by hydropeaking in tailwaters, much of the macroinvertebrate diversity is lost resulting in a few dominant taxa.[3] For example, the Colorado River experiences dramatic flow changes due to the abundance of hydroelectric dams on the river. Below the major dams, between three and seven macroinvertebrate taxa account for over 95% of the total abundance in the system. Nearly half of these species are specialists who spend their entire lives underwater and do not provide energy to the surrounding terrestrial environment.[4]
Native Fish impactsedit
Native fish species are particularly endangered by tailwaters. The construction of the tailwater itself is a severe environmental disturbance that can reduce richness, but immediately following dam completion, many native fish species can still be found. The long-term impacts on native fish communities, especially in historically warmwater systems, are especially dramatic. Before the completion of the Beaver Dam on the Ozark River, 62 species of fish from 19 unique families were present in the system. Following dam construction, only 18 species from 8 families were collected, with two families accounting for over 90% of the fish found. 30 years after the installment of the impoundment, 28 species of fish were sampled from 8 families, however 98% of the fish were either sculpin or trout species, both of which were essentially absent prior to the creation of the tailwater.[5] This lack of species evenness results in an altered aquatic ecosystem that is far from the community makeup seen before the impoundment was in place. Substrate composition in tailwaters can also impact native fish survival. Some species, such as river chubs, construct nests from gravel and rocks found on the river bottom. Tailwater flows can alter substrate size making it difficult for native fish to build spawning areas. Increased flows can also flatten nesting sites or scour eggs from the nest making spawning in a tailwater system more difficult.[6]
Abiotic Impactsedit
The construction of a dam will often change the makeup of the body of water immediately upstream and downstream of the structure. In many cases, the water that comes out of the dam originates from the bottom of the reservoir created by the impoundment. The resulting dam discharge is relatively cold compared to the natural temperature of waterway due to the stratification of water that occurs in reservoirs.[7] The resulting thermal pollution can have devastating impacts on native fish assemblages.
A fisherman at Lee's Ferry on the Colorado River. Here the angler is attempting to catch trout in a place that would be unsuitable for the cold-water fish without the dam upstream.
Tailwaters are also subject to changes in traditional flow rate. Some impoundments discharge a consistent amount of water which can disrupt seasonal fluctuations and extreme flow events. On the other hand, hydropeaking, the cyclical increase in discharge below a hydroelectric dam to meet power demands, can rapidly increase tailwater flow rates. The dramatic changes in river flow can scour the river bottom, change river velocity and depth, and reduce biotic richness in the waterway.[8]
Tailwater Fisheryedit
Tailwater can also refer to a type of fishery. Fishing in tailwaters can be very productive due to consistent water temperature and flow rates found below an impoundment. Nutrients from the lake upstream are released into the tailwater, creating a productive environment in which target fish species, usually trout, can thrive.[9] An example of this phenomenon is the fishery at Lee's Ferry on the Colorado River in Arizona.
^ abBlinn, Dean W.; Shannon, Joseph P.; Benenati, Peggy L.; Wilson, Kevin P. (October 1998). "Algal Ecology in Tailwater Stream Communities: The Colorado River Below Glen Canyon Dam, Arizona". Journal of Phycology. 34 (5): 734–740. doi:10.1046/j.1529-8817.1998.340734.x. S2CID 84290098.
^Valentin, S.; Wasson, J. G.; Philippe, M. (August 1995). "Effects of hydropower peaking on epilithon and invertebrate community trophic structure". Regulated Rivers: Research & Management. 10 (2–4): 105–119. doi:10.1002/rrr.3450100207. ISSN 0886-9375.
^Abernethy, Erin F.; Muehlbauer, Jeffrey D.; Kennedy, Theodore A.; Tonkin, Jonathan D.; Van Driesche, Richard; Lytle, David A. (June 2021). "Hydropeaking intensity and dam proximity limit aquatic invertebrate diversity in the Colorado River Basin". Ecosphere. 12 (6). doi:10.1002/ecs2.3559. ISSN 2150-8925. S2CID 235741472.
^Quinn, Jeffrey W.; Kwak, Thomas J. (January 2003). <0110:faciao>2.0.co;2 "Fish Assemblage Changes in an Ozark River after Impoundment: A Long-Term Perspective". Transactions of the American Fisheries Society. 132 (1): 110–119. doi:10.1577/1548-8659(2003)132<0110:faciao>2.0.co;2. ISSN 0002-8487.
^Peoples, Brandon K.; McManamay, Ryan A.; Orth, Donald J.; Frimpong, Emmanuel A. (2013-07-02). "Nesting habitat use by river chubs in a hydrologically variable Appalachian tailwater". Ecology of Freshwater Fish. 23 (2): 283–293. doi:10.1111/eff.12078. ISSN 0906-6691.
^"Cold water pollution". www.dpi.nsw.gov.au. 2016-04-27. Retrieved 2021-11-12.
^Cushman, Robert M. (1985). "Review of Ecological Effects of Rapidly Varying Flows Downstream from Hydroelectric Facilities". North American Journal of Fisheries Management. 5 (3A): 330–339. doi:10.1577/1548-8659(1985)5<330:ROEEOR>2.0.CO;2. ISSN 1548-8675.
^"Tailwater Fisheries". The Living River. Retrieved 2021-12-07.
December 15, 2023
tailwater, refers, waters, located, immediately, downstream, from, hydraulic, structure, such, spillway, bridge, culvert, generally, measured, reported, average, water, depth, downstream, hydraulic, structure, tailwater, vary, based, outlet, from, structure, w. Tailwater refers to waters located immediately downstream from a hydraulic structure such as a dam spillway bridge or culvert 1 Generally measured and reported as the average water depth downstream of a hydraulic structure tailwater can vary based on the outlet from the structure as well as downstream influences that may restrict or advance the usual flow of water from the structure The creation of a tailwater will have significant impacts on both the abiotic and biotic conditions of the waterway The Colorado River tailwater below Glen Canyon Dam Contents 1 Biotic Impacts 1 1 Macroinvertebrate impacts 1 2 Native Fish impacts 2 Abiotic Impacts 3 Tailwater Fishery 4 ReferencesBiotic Impacts editThe environmental conditions in a tailwater influence the entire food web of the waterway Consistent flows higher temperatures and clear water found in tailwaters create an ideal habitat for filamentous green algae 2 The near shore zones of tailwaters that are submerged during hydropeaking but dry during consistent flows are far less productive areas of the waterway Most algal species are not adapted to handle this exposure to air for extended periods of time resulting in a loss of primary productivity and an increase in organic matter that gets washed away when flow increases 2 Macroinvertebrate impacts edit Macroinvertebrate communities assemblages largely depend on algal composition of the waterway With the conditions created by hydropeaking in tailwaters much of the macroinvertebrate diversity is lost resulting in a few dominant taxa 3 For example the Colorado River experiences dramatic flow changes due to the abundance of hydroelectric dams on the river Below the major dams between three and seven macroinvertebrate taxa account for over 95 of the total abundance in the system Nearly half of these species are specialists who spend their entire lives underwater and do not provide energy to the surrounding terrestrial environment 4 Native Fish impacts edit Native fish species are particularly endangered by tailwaters The construction of the tailwater itself is a severe environmental disturbance that can reduce richness but immediately following dam completion many native fish species can still be found The long term impacts on native fish communities especially in historically warmwater systems are especially dramatic Before the completion of the Beaver Dam on the Ozark River 62 species of fish from 19 unique families were present in the system Following dam construction only 18 species from 8 families were collected with two families accounting for over 90 of the fish found 30 years after the installment of the impoundment 28 species of fish were sampled from 8 families however 98 of the fish were either sculpin or trout species both of which were essentially absent prior to the creation of the tailwater 5 This lack of species evenness results in an altered aquatic ecosystem that is far from the community makeup seen before the impoundment was in place Substrate composition in tailwaters can also impact native fish survival Some species such as river chubs construct nests from gravel and rocks found on the river bottom Tailwater flows can alter substrate size making it difficult for native fish to build spawning areas Increased flows can also flatten nesting sites or scour eggs from the nest making spawning in a tailwater system more difficult 6 Abiotic Impacts editThe construction of a dam will often change the makeup of the body of water immediately upstream and downstream of the structure In many cases the water that comes out of the dam originates from the bottom of the reservoir created by the impoundment The resulting dam discharge is relatively cold compared to the natural temperature of waterway due to the stratification of water that occurs in reservoirs 7 The resulting thermal pollution can have devastating impacts on native fish assemblages nbsp A fisherman at Lee s Ferry on the Colorado River Here the angler is attempting to catch trout in a place that would be unsuitable for the cold water fish without the dam upstream Tailwaters are also subject to changes in traditional flow rate Some impoundments discharge a consistent amount of water which can disrupt seasonal fluctuations and extreme flow events On the other hand hydropeaking the cyclical increase in discharge below a hydroelectric dam to meet power demands can rapidly increase tailwater flow rates The dramatic changes in river flow can scour the river bottom change river velocity and depth and reduce biotic richness in the waterway 8 Tailwater Fishery editTailwater can also refer to a type of fishery Fishing in tailwaters can be very productive due to consistent water temperature and flow rates found below an impoundment Nutrients from the lake upstream are released into the tailwater creating a productive environment in which target fish species usually trout can thrive 9 An example of this phenomenon is the fishery at Lee s Ferry on the Colorado River in Arizona References edit Drainage Terms hancockcoingov org Retrieved 2021 12 07 a b Blinn Dean W Shannon Joseph P Benenati Peggy L Wilson Kevin P October 1998 Algal Ecology in Tailwater Stream Communities The Colorado River Below Glen Canyon Dam Arizona Journal of Phycology 34 5 734 740 doi 10 1046 j 1529 8817 1998 340734 x S2CID 84290098 Valentin S Wasson J G Philippe M August 1995 Effects of hydropower peaking on epilithon and invertebrate community trophic structure Regulated Rivers Research amp Management 10 2 4 105 119 doi 10 1002 rrr 3450100207 ISSN 0886 9375 Abernethy Erin F Muehlbauer Jeffrey D Kennedy Theodore A Tonkin Jonathan D Van Driesche Richard Lytle David A June 2021 Hydropeaking intensity and dam proximity limit aquatic invertebrate diversity in the Colorado River Basin Ecosphere 12 6 doi 10 1002 ecs2 3559 ISSN 2150 8925 S2CID 235741472 Quinn Jeffrey W Kwak Thomas J January 2003 lt 0110 faciao gt 2 0 co 2 Fish Assemblage Changes in an Ozark River after Impoundment A Long Term Perspective Transactions of the American Fisheries Society 132 1 110 119 doi 10 1577 1548 8659 2003 132 lt 0110 faciao gt 2 0 co 2 ISSN 0002 8487 Peoples Brandon K McManamay Ryan A Orth Donald J Frimpong Emmanuel A 2013 07 02 Nesting habitat use by river chubs in a hydrologically variable Appalachian tailwater Ecology of Freshwater Fish 23 2 283 293 doi 10 1111 eff 12078 ISSN 0906 6691 Cold water pollution www dpi nsw gov au 2016 04 27 Retrieved 2021 11 12 Cushman Robert M 1985 Review of Ecological Effects of Rapidly Varying Flows Downstream from Hydroelectric Facilities North American Journal of Fisheries Management 5 3A 330 339 doi 10 1577 1548 8659 1985 5 lt 330 ROEEOR gt 2 0 CO 2 ISSN 1548 8675 Tailwater Fisheries The Living River Retrieved 2021 12 07 Retrieved from https en wikipedia org w index php title Tailwater amp oldid 1189341127, wikipedia, wiki, book, books, library,
