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 Fast hikin, carrot chompin, always grinnin, gear scatterin recipient of the Theta Lake manouver
Burnaby
2047 Posts |
Posted - 03/12/2012 : 5:33 PM
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EXCLUSIVE: RUN-OF-RIVER POWER PROJECTS KILL FISH
Saturday, March 10, 2012 (All day)
Vancouver Sun
Larry Pynn
The Mamquam River pours cold and fresh off the Coast Mountains, forming pools and canyons and chutes of white water on its way to the Squamish River and Howe Sound.
It was a natural place for federal fisheries biologists to assemble on an August 2010 weekend for swift-water safety training. Like the river itself, however, their exercise took an expected turn.
Rather than watch the Mamquam flow predictably to the sea, the biologists were dismayed to witness the water levels fluctuate wildly — and with dire consequences.
Young steelhead were dying, stranded without water.
The culprit? The Capital Power run-of-river hydro plant, located just upstream.
The independent power industry bills itself as green, sustainable and environmentally responsible.
But more than 3,000 pages of documents obtained separately by The Vancouver Sun and the Wilderness Committee through freedom of information requests show water-flow fluctuations caused by run-of-river hydro projects are killing fish — and the problem is not isolated.
While independent power producers insist their sector remains the cleanest energy option, the documents bolster environmentalists’ long-standing concerns about the industry.
“I’m seeing significant environmental problems,” said Gwen Barlee, policy director for the Wilderness Committee. “And that runs completely counter to what the companies are saying, which is essentially, ‘Trust us with your wild rivers and there won’t be any problems.’ ”
The documents detail repeated short-term fluctuations in water flows, resulting in the stranding and killing of juvenile fish downstream of two plants, Capital Power on the lower Mamquam and Innergex on Ashlu Creek, another tributary of the Squamish.
In one incident on Ashlu Creek, on May 8, 2010, 166 salmon and trout fry became stranded due to rapidly dropping water levels. Fewer than half of the fry could be returned to the creek alive. Another 39 fry died during a stranding on April 20, 2011.
Neither hydro operation has been charged.
At present, there are 50 private hydro projects in operation and selling power to BC Hydro, half of them in the south coast region. Another 62 are in the planning or construction phase. Applications are outstanding for another 635 water-power projects, although not all are expected to be approved.
Run-of-river projects produce electricity by diverting river water — typically in a steep canyon — and sending it through an underground pipe to a powerhouse. The water is then returned to the river.
The provincial and federal governments work together to set regulations for run-of-river projects, including general minimum stream flows and specific rates for short-term fluctuations — known as ramping.
Ramping may occur for reasons such as the shutdown of a power plant for maintenance or an unanticipated failure.
During this process, water levels rise and fall in the river, but power producers are supposed to ensure these changes are made gradually — a maximum 2.5 centimetres per hour to prevent stranding of fry that inhabit the shallow edges of the river downstream.
Water is money to this fast-growing industry. The volume of water that power plants are required to leave in streams on a continuing basis as well as the rate of short-term ramping affect their ability to produce electricity. The more water they have to leave in the river, the less they have for power production.
Companies “argue economic hardship” when it comes to diverting water because of fish, the federal department of fisheries and oceans (DFO) states in minutes of a July 21, 2001, inter-agency meeting on a proposed run-of-river project on the Kokish River on northeastern Vancouver Island.
Government officials face a “significant challenge” to reduce water available for power generation “because proponents are reluctant to reduce revenues,” the minutes stated.
The Kokish example is “not different from other operating projects that have not been accurately managed,” the documents went on to state.
DFO has observed “considerable non-compliance,” and the success rate of complying with in-stream flow requirements “is not very good.”
Adam Lewis, president of Ecofish Research Ltd., a leading consultant to industry and government on run-of-river projects, said all run-of-river power projects have some negative effect on the environment.
Fish living upstream can get sucked into the intake pipes and killed in the turbines, said Lewis, who is also a former director of the Steelhead Society of B.C.
But the larger issue, he suggested, is the potential for power plants to ramp down water levels too quickly and leave young fish stranded and dead for kilometres downstream.
Emerging salmon eggs are especially sensitive in March and April; steelhead and trout in July and August.
The freedom-of-information documents reveal the frustration of provincial and federal bureaucrats with continuing problems at the Ashlu and lower Mamquam plants.
The Capital Power plant, built in 1996 with no requirement for monitoring, continued to be plagued by fish issues well after fisheries biologists first discovered the dead steelhead on Aug. 28, 2010. Capital Power sold the 50-megawatt facility to Atlantic Power, a Boston-based publicly traded company, in November 2011. Atlantic Power refused interview requests from The Sun.
In a letter to Capital Power dated Sept. 9, 2011, federal habitat biologist Francesca Knight and hydrotechnical engineer Vince Busto expressed concern over at least 19 known incidents over the previous 12-month period.
They warned that the death of newly emerged salmonid fry are of “great concern” and demanded that the company operate in a manner that does not destroy fish or their habitat.
The federal fisheries department refused to allow anyone to be interviewed by The Sun.
However, in a written statement, the department said it has “issued warning letters to Capital Power advising the company to increase the discharge of water into the river from the hydro project to protect fish and fish habitat. As a result of this work, the company has upgraded its turbines and the computer systems and equipment that regulate water flow from the facility into the Mamquam River.”
The freedom-of-information documents show similar concerns about the Ashlu Creek plant, built by Ledcor Power Inc. and now owned by Quebec-based Innergex.
Officials expressed concerns over insufficient water flows over a fish ladder designed for rainbow trout and ramping events stranding young fish.
In an April 26, 2010 email, provincial fisheries biologist Erin Stoddard stated: “In my opinion the strandings to date would have resulted in fish kills, and would have impacted the population.”
He called it a “significant issue that should have and could have been resolved a long time ago by Innergex, especially as they were ordered to address it by DFO.”
Stoddard’s concerns proved prophetic. A “technical problem” at the Innergex plant on Ashlu Creek on May 8, 2010, left an estimated area of 6,086 square metres high and dry downstream for a distance of 1.7 kilometres.
Officials counted 166 fry, including 62 chinook, 71 coho, four pink salmon, 18 dolly varden/bull trout (both provincially blue-listed species of special concern) and 11 unidentified salmonids.
Days later, on May 13, 2010, Stoddard wrote that “there is not enough flow going through the ladder for an adult-sized rainbow to migrate upstream.”
Mike Nelson of Cascade Environmental Resource Group Ltd. warned on June 1, 2010, of “trying to fix a significant problem by trying to do little changes.”
And on April 26, 2011, Scott Barrett, a provincial section head of ecosystems, complained, “we are spending a large amount of people resources ... on holding the hand of this industry” to bring them into compliance.
The federal fisheries department refused to comment on Ashlu Creek, but confirmed it is investigating one run-of-river operation to determine whether charges should be laid.
Innergex conceded it encountered problems after its 50-megawatt Ashlu plant started operations in November 2009, but insisted it is improving operations to ensure compliance.
Matt Kennedy, the company’s vice-president of environment, described the death of the 166 fish as an “unfortunate incident” that occurred in the early stages of the commissioning of the plant.
“We essentially operate the plant differently,” he insisted. “We don’t feel it’s acceptable for our company to have those sorts of things going on. So we’ve changed our policies and procedures.”
Richard Blanchet, the company’s senior vice-president, noted that almost five per cent of the $130-million cost of the Ashlu Creek project is related to meeting ramping requirements.
Innergex is now conducting a formal five-year monitoring program to determine the effects on fish and to guide modifications as required. “Innergex is fully committed and responsive to address these issues and is trying its best to avoid any incident,” Blanchet said.
Innergex has developed 60,000 square metres of spawning channels below the dam as compensation for construction of the plant. The company estimates the channels produce 100,000 fry per year, although it’s unknown how many of those fish are additional to the system or might have spawned elsewhere in the absence of the channels.
“We’re very pleased with that, it’s a very important part of our project,” Kennedy said.
Despite the events revealed in the documents, the run-of-river power industry says its projects have fewer environmental impacts on fish than traditional BC Hydro dams. They also do not emit the greenhouse gases such as carbon dioxide associated with power production from burning fossil fuels.
Clean Energy B.C. (an industry group formerly called the Independent Power Association of B.C.) boasts in a two-page, run-of-river fact sheet that the industry is sustainable “green electricity” and that its projects are developed responsibly with “minimal impact” on vegetation, bird or wildlife habitat.
The word “fish” is mentioned only once.
Clean Energy B.C. executive director Paul Kariya confirmed it is “probably for sure that every hydro project ever developed in B.C. has killed fish,” be it private or public. “Sadly all developments like this have impacts,” he said.
“Isn’t the bigger question, how are we going to power our province in the future? We need electricity and this demand will grow in excess of what we can do through conservation.”
Does that make run-of-river projects green?
“The green label is very subjective,” responded Julia Berardinucci, the south coast’s director of resource management for the Ministry of Forests, Lands and Natural Resource Operations.
“I would want to refrain from saying yes or no, one way or the other.”
Berardinucci said run-of-river projects represent an “emerging technology” operating in a “challenging landscape.”
The government’s regulation of such projects and industry’s response are both improving, she argued.
“We’re seeing some incidents occurring, but relative to the number of [power] plant operations, it’s obviously a point of opinion as to whether it’s having obvious impacts,” she said from her Surrey office.
“The potential risk is always there for all the plants....”
Improved plant design standards and monitoring of operations along with continuing “learn-as-we-go” revisions to ramping guidelines are all improving the situation, she said.
The federal fisheries department said in its statement it is developing monitoring procedures to improve the assessment of impacts from run-of-river projects.
In collaboration with industry and the B.C. government, the department is also developing a ramping guide to reduce impacts to fish and fish habitat.
Environmentalists are not satisfied and say it is time to put the brakes on an industry shown to be not environmentally benign.
The Wilderness Committee is calling for a moratorium on further approvals of such projects and federal charges where fish and fish habitat have suffered.
“You have poor planning and low environmental standards,” said Barlee, whose group has been a leading critic of run-of-river projects over the years. “These projects shouldn’t be situated in fish habitat at all.”
http://wildernesscommittee.org/news/exclusive_run_of_river_power_projects_kill_fish
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Mysterious, pop can stove stashin', gps totin', overnighter virgin, wannabe tentmaker and foul weather wuss who rides a thumper to the trailhead with wonderdog Max to hike the Chilliwack Valley
Chwk
Canada
4921 Posts |
Posted - 03/12/2012 : 7:48 PM
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Thank you, BC Liberals!
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Vancouver
1826 Posts |
Posted - 03/12/2012 : 8:18 PM
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"Run of River" projects were first sold to the public on the basis they would be placed only in streams that had no fish. Or portions of streams that had no fish. Often, this would be above an impassable waterfall, as was the case for Miller Creek just outside Pemberton.
Without any publicity that I recall, this parameter was dropped in favor of provisions to minimize effects on fish. If indeed there was no notice of that change, then it amounts to a violation of trust. So what else is new. |
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Trail running, bike hucking, fast packing, beer drinking collector of pine cones on a day pass
AKA
Dances with Trees
Forest Gnome Cabin
Canada
13090 Posts |
Posted - 03/12/2012 : 8:38 PM
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quote:
Originally posted by sgRant
"Run of River" projects were first sold to the public on the basis they would be placed only in streams that had no fish. Or portions of streams that had no fish. Often, this would be above an impassable waterfall, as was the case for Miller Creek just outside Pemberton.
Without any publicity that I recall, this parameter was dropped in favor of provisions to minimize effects on fish. If indeed there was no notice of that change, then it amounts to a violation of trust. So what else is new.
Well said. A lot of people forget that when these projects started only non fish bearing streams were supposed to be targeted for projects. |
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3022 Posts |
Posted - 03/12/2012 : 10:11 PM
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Didn't notice any mention about the noise level. The two I know of are extreme noise and carries kms away along a 'tranquil' watershed>Kennedy River.
Why would that be and why isn't noise-supression used? |
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100 Mile House, BC
Canada
178 Posts |
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Vancouver
1826 Posts |
Posted - 03/12/2012 : 11:40 PM
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quote:
Originally posted by HT
Former CEO of BC Hydro said last year that Govt policy is forcing BC Hydro to buy power from IPPs that it doesn't need:
http://www.canada.com/vancouversun/news/westcoastnews/story.html?id=9c7f6e08-e6b0-4374-a763-f1c2b5190ec6
The current provincial government is backing down on this. Partly because it's become obvious even to them that it's a stupid idea. The other reason is because they have to make it look like BC can meet the gigantic electricity needs of the LNG compression plants they want to build in the NW of the province. |
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Coquitlam, BC
Canada
343 Posts |
Posted - 03/13/2012 : 09:04 AM
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Couple notes from an engineering perspective -
Ramping rates and in-stream flow requirements (IFRs): these are the key issues with respect to the availability of water within streams that are regulated (be they by run of river, storage hydro (i.e. BC Hydro dams), or any other sort of river diversion or withdrawal system).
IFRs are developed from an ecological perspective and are typically related as a percentage of the mean annual discharge of the stream assessed on a month by month basis (i.e. if salmonids spawn in October then you may see 10% in August, 20% in Sept, 30% in Oct, 20% in Nov). The IFR values are negotiated between DFO and either IPP/BC Hydro (I don't know if this also applies to any other residential/commercial/industrial withdrawals of water). The actual instream flow is typically measured using a real-time water level transducer - or more aptly by a network of transducers located in a variety of stream reaches both upstream and downstream of the intake location. The water levels are tied to what is known as a rating curve which is derived by taking stream flow measurements at the varying depths of flow. The rating curve relates the depth of the stream to a corresponding rate of discharge (flow rate).
Ramping rates on the other hand are an operational tool that are intended to prevent temporary loss of wetted reaches downstream of an intake. This can occur when abrupt changes to the flow regime are forced by operational changes (i.e. the intake is closed which may result in no water being released back into the stream at the powerhouse tailrace - correspondingly there would be a pulse of excess water which would then discharge into the natural stream channel). Ecofish's description is better than mine: http://www.ecofishresearch.com/documents/EcofishPoster-SettingFlowRampingRequirements.pdf
Noise suppression - there are typically two causes of noise emission from run-of-river hydro facilities: hydromechanical noise and tailrace noise. A lot of this can be mitigated by good design and selection of powerhouse site. There is a lot of effort being put into developing better means of noise elimination (as we all know, noise is a form of energy loss).
C
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100 Mile House, BC
Canada
178 Posts |
Posted - 03/13/2012 : 09:15 AM
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| Run-of-river projects, some of which are owned by foreign or non-BC companies, are causing fish mortality, while selling power to BC Hydro that BC Hydro doesn't need, at prices well above the electricity market rate. |
Edited by - HT on 03/13/2012 09:31 AM |
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3022 Posts |
Posted - 03/13/2012 : 12:01 PM
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quote:
Originally posted by caurala
Couple notes from an engineering perspective -
Ramping rates and in-stream flow requirements (IFRs): these are the key issues with respect to the availability of water within streams that are regulated (be they by run of river, storage hydro (i.e. BC Hydro dams), or any other sort of river diversion or withdrawal system).
IFRs are developed from an ecological perspective and are typically related as a percentage of the mean annual discharge of the stream assessed on a month by month basis (i.e. if salmonids spawn in October then you may see 10% in August, 20% in Sept, 30% in Oct, 20% in Nov). The IFR values are negotiated between DFO and either IPP/BC Hydro (I don't know if this also applies to any other residential/commercial/industrial withdrawals of water). The actual instream flow is typically measured using a real-time water level transducer - or more aptly by a network of transducers located in a variety of stream reaches both upstream and downstream of the intake location. The water levels are tied to what is known as a rating curve which is derived by taking stream flow measurements at the varying depths of flow. The rating curve relates the depth of the stream to a corresponding rate of discharge (flow rate).
Ramping rates on the other hand are an operational tool that are intended to prevent temporary loss of wetted reaches downstream of an intake. This can occur when abrupt changes to the flow regime are forced by operational changes (i.e. the intake is closed which may result in no water being released back into the stream at the powerhouse tailrace - correspondingly there would be a pulse of excess water which would then discharge into the natural stream channel). Ecofish's description is better than mine: http://www.ecofishresearch.com/documents/EcofishPoster-SettingFlowRampingRequirements.pdf
Noise suppression - there are typically two causes of noise emission from run-of-river hydro facilities: hydromechanical noise and tailrace noise. A lot of this can be mitigated by good design and selection of powerhouse site. There is a lot of effort being put into developing better means of noise elimination (as we all know, noise is a form of energy loss).
C
thankyou for the insight.
I guess the MLAs sitting in Victoria parliament buildings are well removed from that noise and I have yet-to-date to meet a single MLA on any river or trail in my life, that isn't there for a photo-op. |
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Coquitlam, BC
Canada
343 Posts |
Posted - 03/13/2012 : 12:51 PM
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A good design and well-tuned operations can make a good project that has the ability to minimize impacts such as fish mortality. You can't paint all independent power producers with the same brush, and like anything there are good proponents and better proponents (and the reality is that a lot of the proponents don't make it beyond staking a water license - simply because they don't or cannot achieve regulatory expectations or a social license to develop their projects).
It is important that IPPs as well as BC Hydro are held accountable where appropriate - and part of this means that is the timely release of information to the public and rational watchdog organizations (i.e. not an alarmist that has an anti-agenda, but someone who is going to look at the information and judge it for what it is).
The article's author quoted meeting minutes from 2001 - this is not timely enough and it does not give any resulting actions - that was 11 years ago! There is a much better understanding and rigorous approach to developing ramping rates. From the proponent's perspective ramping impacts their revenue stream but it's not a daily reality and it's on the level with any type of operations and maintenance costs. Smart businesses invest in their infrastructure to reduce in O&M and in the same token smart power producers can reduce the cost of ramping by minimizing the need to ramp and providing measures that protect in stream habitat.
As always, it's important not to confuse rhetoric with fact. Larry Pynn's article is biased and I suspect that there is a lot of wordsmithing that takes the quoted comments out of their original intended context. To his credit, he does note that there are improvements to the way that things were done (i.e. ramping guidelines and a growing database of information from which to base sound decision making upon).
C
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Vancouver, BC
Canada
1425 Posts |
Posted - 03/13/2012 : 1:36 PM
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quote:
Originally posted by sgRant
"Run of River" projects were first sold to the public on the basis they would be placed only in streams that had no fish. Or portions of streams that had no fish. Often, this would be above an impassable waterfall, as was the case for Miller Creek just outside Pemberton.
Without any publicity that I recall, this parameter was dropped in favor of provisions to minimize effects on fish. If indeed there was no notice of that change, then it amounts to a violation of trust. So what else is new.
These IPPs are indeed on portions of streams that have no fish, but they affect the water flow downstream of the powerhouse which is often good fish habitat. If an IPP is chugging along and suddenly shuts down, water stops coming out of the powerhouse immediately. But it takes a while for the diverted flow to make it's way down the natual channel to the powerhouse. In the mean time the river downstream of the powerhouse can lose a lot of it's water. |
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Vancouver
1826 Posts |
Posted - 03/13/2012 : 3:01 PM
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quote:
Originally posted by scottN
quote:
Originally posted by sgRant
"Run of River" projects were first sold to the public on the basis they would be placed only in streams that had no fish. Or portions of streams that had no fish. Often, this would be above an impassable waterfall, as was the case for Miller Creek just outside Pemberton.
Without any publicity that I recall, this parameter was dropped in favor of provisions to minimize effects on fish. If indeed there was no notice of that change, then it amounts to a violation of trust. So what else is new.
These IPPs are indeed on portions of streams that have no fish, but they affect the water flow downstream of the powerhouse which is often good fish habitat. If an IPP is chugging along and suddenly shuts down, water stops coming out of the powerhouse immediately. But it takes a while for the diverted flow to make it's way down the natual channel to the powerhouse. In the mean time the river downstream of the powerhouse can lose a lot of it's water.
And we were also told run of river projects were better than dams because they didn't have dams and reservoirs. It turns out they have weirs, some of them large enough to create very large "headponds". |
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Coquitlam, BC
Canada
343 Posts |
Posted - 03/14/2012 : 08:21 AM
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sGrant - you would be hardpressed to call a headpond a reservoir - it's about the residence time of the impounded water. In a run-of-river scheme, the head pond serves a handful of functions: 1) promote quiescent, efficient flow into the intake, 2) provide a measure of protection against debris and coarse sediment from impacting the intake structure, and 3) provide a suitable level of submergence over the intake (this prevents cavitation - air bubbles that become entrained in the water entering the penstock which may implode and cause damage to hydromechanical equipment or the inner wall of the penstock).
Most headponds are design to infill will coarse sediment over time so the long term effect is that most headponds will have very limited storage - on the other hand, in some stream systems there is an operating protocol in hand to ensure that some sediment is released - this process is called sediment recruitment and it is essential for the ongoing aggradation and degradation of the downstream river reaches (i.e. it replenished the sediment that is continually lost and gained at features such as gravel bars and estuaries).
In other circumstances the coarse sediment captured in the headponds is re-suspended during periods of high flow. This scoured material is then deposited in areas where the stream flow energy is unable to mobilize it further - again in locations such as gravel bars and estuaries.
On another note - there is a clear distinction between a weir and a dam - weirs are flow-over structures while dams are intended to impound water and route water through an intake or spillway. Storage is a key characteristic that separates weirs from dams and run-of-river from storage hydro, accordingly.
C |
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Coquitlam, BC
Canada
343 Posts |
Posted - 03/14/2012 : 2:05 PM
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One other thing to note is that many of the projects (i.e. Mamquam) that have been noted were permitted under a different regime before there was a good understanding of what ramping is or how it should occur.
There is of course opposition from the operators who are likely honouring the permits and approvals that they have in place to the full extent that they have been approved (many of which were placed under the NDP government - just my slight jab at that party given their current "moratorium" stance that contradicts many of the policies that they implemented to stimulate the independent power producer industry).
While the hand of the operators has not been forced to date, they are acutely aware of the implications of stricter operating regimes and most (if not all) are working with engineers, environmental scientists and regulators to update their facilities and/or operating procedures.
C |
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Vancouver
1826 Posts |
Posted - 03/14/2012 : 2:49 PM
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quote:
Originally posted by caurala
sGrant - you would be hardpressed to call a headpond a reservoir - it's about the residence time of the impounded water. In a run-of-river scheme, the head pond serves a handful of functions: 1) promote quiescent, efficient flow into the intake, 2) provide a measure of protection against debris and coarse sediment from impacting the intake structure, and 3) provide a suitable level of submergence over the intake (this prevents cavitation - air bubbles that become entrained in the water entering the penstock which may implode and cause damage to hydromechanical equipment or the inner wall of the penstock).
Most headponds are design to infill will coarse sediment over time so the long term effect is that most headponds will have very limited storage - on the other hand, in some stream systems there is an operating protocol in hand to ensure that some sediment is released - this process is called sediment recruitment and it is essential for the ongoing aggradation and degradation of the downstream river reaches (i.e. it replenished the sediment that is continually lost and gained at features such as gravel bars and estuaries).
In other circumstances the coarse sediment captured in the headponds is re-suspended during periods of high flow. This scoured material is then deposited in areas where the stream flow energy is unable to mobilize it further - again in locations such as gravel bars and estuaries.
On another note - there is a clear distinction between a weir and a dam - weirs are flow-over structures while dams are intended to impound water and route water through an intake or spillway. Storage is a key characteristic that separates weirs from dams and run-of-river from storage hydro, accordingly.
C
What I was getting at is that when run of river projects were first described to the public, I don't recall any mention of headponds. Later, headponds were described as being needed to keep the intake submerged. You probably know better than I do how common large headponds are and how large they are, but my impression is that some of them are quite large and may even have surface areas larger than some non-hydro reservoirs behind dams.
Are any of these weirs and headponds, besides the uses you described, used as small reservoirs: to store water during high inflow for the purpose of generating power during low inflow?
I hadn't heard that part of the design considerations for headponds was that they silt up. Wouldn't that end their capability to provide the benefits you described? |
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676 Posts |
Posted - 03/14/2012 : 2:58 PM
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quote:
Originally posted by caurala
... and 3) provide a suitable level of submergence over the intake (this prevents cavitation - air bubbles that become entrained in the water entering the penstock which may implode and cause damage to hydromechanical equipment or the inner wall of the penstock)...
Technical language police here: Cavitation is not entrained air bubbles. Cavitation is a phenomena caused by the localized pressure dropping below the vapour pressure of the fluid, causing vapour bubbles to appear in the fluid, then collapse with considerable force when the pressure rises again. Common in pumps, propellers, anytime a fluid has a sudden change in flow vector. Entrained air bubbles can cause damage similar in appearance, but is not the same. True cavitation is rare but not unknown in power turbines as the working pressure is usually high enough to prevent the local pressure from dropping below the critical point.
Entrained air bubbles are a common and serious problem for water turbines, entirely correct, but are not cavitation. </language police mode>
Don't worry, once Harper pushes through the sneaky change to the fisheries act all the problems caused by the run-of-river projects will no longer be a problem. The fish will still die, but it won't be illegal to harm the habitat anymore hence not a problem. You gotta love the Conservatives and their business backers! I mean it, that is next on the agenda, to make it an act of terrorism to not support them. Crush all dissent! |
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Coquitlam, BC
Canada
343 Posts |
Posted - 03/14/2012 : 3:25 PM
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Thanks for the correction on cavitation alex, you are correct.
sGrant - the size of the headponds is mostly a function of the topography upstream of the intake weir. For all intents and purposes you can assume that the headpond inundation fluctuates from the contour even with the elevation of the crest of the weir, increasing in area as the water level rises. There is a backwater effect as water "stacks" up behind the weir, but for the small reach lengths that you would see with a typical run-of-river scheme this is hardly appreciable.
Beyond the purposes that I described, the headponds are not intended as storage. If they were, it would be of much utility to the operator and the ability to store water means that they can "shape" the generation of electricity generation (i.e. like BC Hydro switching on generators at GM Shrum or Mica when Vancouver's power demands are peaking - mornings and dinner time). As it stands, run-of-river operations can only generate when the river flows (with excess water after instream flow requirements have been met).
Another of the projects on the anti-IPP radar is Kokish - which is in very valuable fish habitat. In all likelihood during low flow months in the summer it will not divert any water from the stream. The reason it is a valuable project is the fact that it has high generation potential in the winter months (thus more valuable to BC Hydro's demands). The power that is generated in the winter months (when BC Hydro is replenishing stored water behind its big dams and power demand is high for things like heating) is attributed a higher payout rate than during summer months when demand is lower and there is surplus storage at BC Hydro's dams.
With a good design, the siltation of a headpond should not adversely affect the operation of a run-of-river system - provided that the material does not end up going into the intake or the accumulation of material alters the bedform to an extent that the stream diverts around the intake structure (not very likely in most cases).
C |
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676 Posts |
Posted - 03/14/2012 : 6:22 PM
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One of the really big environmental problems with conventional dams is the removal of gravel/sand from the downstream river. Without a constant flow of new material to replace what washed on down gravel beds vanish with adverse effects on fish habitat. Locally, I know the Seymour river has gravel added to it regularly to replace what should be there and is instead slowly filling in the reservoir. Silt is generally bad for the fish, but sand and gravel is essential. Unfortunately, dams are much more efficient at removing sand/gravel than fine silt, so the effect is compounded.
At least run-of-river doesn't have this effect. Most of the bad effects of run-of-river COULD be greatly mitigated given better design and especially operating practices, but this just isn't happening nor will it under current conditions.
Of course conventional dams could be far better than they are as well, unlike run-of-river even to the point of being a net positive for the fish, but again I'm not holding my breath. |
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Hope, BC
Canada
7130 Posts |
Posted - 03/14/2012 : 6:30 PM
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| There has been tests done and the results are that fish ladders actually help the fish, and can help produce larger fish numbers. But if these guys are mismanaging the water levels that is an entirely different story. |
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North Vancouver, BC
Canada
1273 Posts |
Posted - 03/14/2012 : 8:10 PM
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| Twas news to me that the ROR are in habitat areas whereas I thot they were above that zone. That opens a whole new can of worms doesn't it. |
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Run of river = not good for fish. Surprised??
