As Puerto Rico continues to grapple with the aftermath of Hurricane Maria, information on damage to the Guajataca Dam remains scarce, while reports suggest spillway repairs may be ongoing.
Hurricane Maria made landfall in Puerto Rico last month, bringing 150 mph winds and 20 inches of rain. Damage to infrastructure was widespread, and the destruction of electricity and communications networks hindered efforts to assess the damage and move toward recovery.
Early reports suggested that the Guajataca Dam had "failed". On September 22, the National Weather Service's San Juan office tweeted an alert of a "flash flood emergency for a dam failure" at the Guajataca Dam and noted ongoing evacuations.
But as reported by Vox on September 30, an Army Corps spokesman said that the dam was not breached and "has not failed and not collapsed." The article described damage to the dam's overflow spillway.
According to a Department of Defense posting dated October 1, 2017, the Defense Department has deployed more response capacity to Puerto Rico, while the Guajataca Dam spillway continued to erode. The Defense Department said U.S.
Transportation Command delivered 900 super sandbags for spillway
stabilization to Aguadilla Airport on September 30, and that spillway sandbag installation by the Army Corps of Engineers would start on October 1 and will be complete by October 2.
An article posted by The Independent on October 4 describes the Army Corps' use of Osprey V2 rotor-tilt heavy-lift aircraft to drop concrete barriers from the dam into the spillway, in an attempt to limit further erosion of the spillway channel. The article says the "channel has suffered serious erosion as much of its cement cladding was washed away."
Dam safety and flood control spillway damage have featured prominently in recent news. California's Oroville Dam's spillway was damaged earlier this year, including a
concrete failure on the lower chute of the gated flood control spillway,
severe erosion under the gated spillway, and erosion in the areas on
the hillside beneath the emergency spillway. According to the California Department of Water Resources, repairs at Oroville Dam will remain ongoing into 2018 or beyond.
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Showing posts with label dam safety. Show all posts
Showing posts with label dam safety. Show all posts
Oroville Dam evacuation and relicensing
Tuesday, February 14, 2017
A California dam in the midst of a federal relicensing process has experienced flooding and storm-related damage, prompting the evacuation of over 180,000 people. Evacuation orders and a reservoir drawdown represent the most rapid responses to the Oroville Dam incident -- but future discussions of engineering, dam safety, and public policy are likely to continue after the emergency has been resolved.
Oroville Dam is the tallest dam in the U.S.: a 770-foot high earthfill embankment dam on the Feather River in northern California. The dam was built from 1961-1968 by the California Department of Water Resources, as part of the State Water Project. The resulting impoundment, Lake Oroville, can store over 3.5 million acre-feet of water, making it California's second largest man-made lake.
The Oroville project is subject to licensing by the Federal Energy Regulatory Commission under the Federal Power Act. Its first license was issued on February 11, 1957, for a 50-year term which expired on January 31, 2007. The Department of Water Resources filed an application for a new license for the project, which remains pending in Docket No. P-2100, although a settlement agreement was also filed. In the meantime, the project continues to operate under a series of annual licenses issued by the Commission. According to a DWR website, it "anticipates that FERC will issue a new license order in 2017 pending issuance of the aquatic biological opinion from the National Marine Fisheries Service."
According to state documents, California was hit by three major storms during January and February 2017, with major rain and runoff. As Lake Oroville reached its full capacity, operators opened a spillway to allow excess water through the dam. But on February 7, the spillway began to erode. Four days later, operators opened the auxiliary emergency spillway, but eventually determined that this too was "in danger of failing." Since a failure could cause widespread and severe flooding, officials called for evacuations downstream in the Feather River Valley. On February 12, Governor Edmund G. Brown Jr. issued an emergency order strengthening the state's response.
Focus for now remains on safely resolving the risks that the Oroville Dam or its spillways might fail in a way that releases damaging waters. The Commission could investigate what happened under its authority over the project through its existing license. It could also raise issues relating to the incident in the context of the project's relicensing. That case has been pending for roughly a decade, with a settlement agreement having been reached years ago. But it is possible that the 2017 Oroville Dam incident could have consequences in the relicensing context, such as revised spillway designs or operating plans that could be reflected as conditions in a new license.
Oroville Dam is the tallest dam in the U.S.: a 770-foot high earthfill embankment dam on the Feather River in northern California. The dam was built from 1961-1968 by the California Department of Water Resources, as part of the State Water Project. The resulting impoundment, Lake Oroville, can store over 3.5 million acre-feet of water, making it California's second largest man-made lake.
The Oroville project is subject to licensing by the Federal Energy Regulatory Commission under the Federal Power Act. Its first license was issued on February 11, 1957, for a 50-year term which expired on January 31, 2007. The Department of Water Resources filed an application for a new license for the project, which remains pending in Docket No. P-2100, although a settlement agreement was also filed. In the meantime, the project continues to operate under a series of annual licenses issued by the Commission. According to a DWR website, it "anticipates that FERC will issue a new license order in 2017 pending issuance of the aquatic biological opinion from the National Marine Fisheries Service."
According to state documents, California was hit by three major storms during January and February 2017, with major rain and runoff. As Lake Oroville reached its full capacity, operators opened a spillway to allow excess water through the dam. But on February 7, the spillway began to erode. Four days later, operators opened the auxiliary emergency spillway, but eventually determined that this too was "in danger of failing." Since a failure could cause widespread and severe flooding, officials called for evacuations downstream in the Feather River Valley. On February 12, Governor Edmund G. Brown Jr. issued an emergency order strengthening the state's response.
Focus for now remains on safely resolving the risks that the Oroville Dam or its spillways might fail in a way that releases damaging waters. The Commission could investigate what happened under its authority over the project through its existing license. It could also raise issues relating to the incident in the context of the project's relicensing. That case has been pending for roughly a decade, with a settlement agreement having been reached years ago. But it is possible that the 2017 Oroville Dam incident could have consequences in the relicensing context, such as revised spillway designs or operating plans that could be reflected as conditions in a new license.
Civil engineers grade Maine dams D+
Wednesday, December 12, 2012
A group of civil engineers have released a report card for Maine infrastructure, giving Maine a C- overall and giving Maine's dams a D+.
ASCE's 2012 Report Card for Maine's Infrastructure (71-page PDF) comes four years after its first Report Card was issued in 2008. The Report Card covers infrastructure including roads, bridges, railroads, ports and waterways, passenger transportation, airports, dams, municipal wastewater, municipal drinking water, contaminated site remediation, solid waste, schools, energy, and state parks. It was prepared by a team of nineteen ASCE infrastructure leaders who analyzed issues including existing conditions, capacity, operations & maintenance or deferred maintenance, public safety & security, risk and consequences of failure, and current and projected levels of funding.
As the report notes, Maine has over a 1,000 dams, mostly privately owned. 153 of Maine's dams are classified as high- or significant-hazard-potential. Dam safety is an important issue, both for dam owners and from a public policy perspective. When dams fail, they can pose risks to people, communities, properties, and the environment. According to the report, 131 federally regulated dams are in good repair, but most non-hydropower dams are subject only to state regulation. Most of Maine’s dams are low-hazard potential, but are more than 50 years old. Moreover, most of these dams do not generate revenues, making it harder to fund their upkeep even though they may provide values like maintaining lake environments for people and wildlife.
The ASCE report finds that Maine continues to fall well below the needed funding for dam safety inspectors and ranks near the bottom nationally for dam safety program funding. The report critiques Maine’s Dam Safety Program, which spends much less than the other Northern New England states, is understaffed and has no enforcement division.
Will the ASCE report card lead to changes in how Maine regulates dams? What funding sources are available to help private dam owners maintain their facilities in safe condition? Will the state respond by revamping its dam safety program?
ASCE's 2012 Report Card for Maine's Infrastructure (71-page PDF) comes four years after its first Report Card was issued in 2008. The Report Card covers infrastructure including roads, bridges, railroads, ports and waterways, passenger transportation, airports, dams, municipal wastewater, municipal drinking water, contaminated site remediation, solid waste, schools, energy, and state parks. It was prepared by a team of nineteen ASCE infrastructure leaders who analyzed issues including existing conditions, capacity, operations & maintenance or deferred maintenance, public safety & security, risk and consequences of failure, and current and projected levels of funding.
As the report notes, Maine has over a 1,000 dams, mostly privately owned. 153 of Maine's dams are classified as high- or significant-hazard-potential. Dam safety is an important issue, both for dam owners and from a public policy perspective. When dams fail, they can pose risks to people, communities, properties, and the environment. According to the report, 131 federally regulated dams are in good repair, but most non-hydropower dams are subject only to state regulation. Most of Maine’s dams are low-hazard potential, but are more than 50 years old. Moreover, most of these dams do not generate revenues, making it harder to fund their upkeep even though they may provide values like maintaining lake environments for people and wildlife.
The ASCE report finds that Maine continues to fall well below the needed funding for dam safety inspectors and ranks near the bottom nationally for dam safety program funding. The report critiques Maine’s Dam Safety Program, which spends much less than the other Northern New England states, is understaffed and has no enforcement division.
Will the ASCE report card lead to changes in how Maine regulates dams? What funding sources are available to help private dam owners maintain their facilities in safe condition? Will the state respond by revamping its dam safety program?
Inflatable flashboards at hydro dams
Thursday, February 9, 2012
Dam owners are increasingly enhancing their revenue by using inflatable flashboards to optimize their hydroelectric production. This new technology offers dam owners and operators increased safety and increased hydroelectric generation, as well as opening the door to tax credits and other incentives.
Flashboards have traditionally been a palisade of wooden boards inserted into the top of a dam's crest. Flashboards increase a dam's capacity to hold water. They are typically used seasonally in temperate climates, and are removed before winter. Flooding or even high water can wash flashboards away, impairing the dam's ability to hold water until they can be replaced. Replacing flashboards can entail danger to personnel, and it might be a long time before water levels recede enough to allow safe reinstallation. In the meantime, a dam's ability to safely store water can be reduced.
Inflatable flashboards allow operators to increase or decrease the effective height of the flashboard system remotely. The ability to quickly and safely restore pond elevation after a high flow event translates into increased electricity generation. For example, inflatable flashboards at the Deer Rips - Androscoggin 3 Hydroelectric Project on the Androscoggin River in Lewiston and Auburn, Maine, have been calculated as likely to increase electric generation by 4.56% compared to a historical baseline.
This incremental hydropower generation can be valuable to the dam owner. Not only does it allow the facility to produce more electricity, but it may also qualify the project for federal and state tax incentives. For example, Section 45 of the Internal Revenue Code provides a renewable energy tax credit to owners or operators of qualified renewable electric generation facilities. That credit was extended to the incremental production gains from efficiency improvements or capacity additions developed between 2005 and 2013. Developers can ask the Federal Energy Regulatory Commission to certify a historic baseline of power produced at existing dams, as well as the incremental increase in hydropower production due to qualifying investments. Once FERC has issued this certification, dam owners can provide that to the Internal Revenue Service to receive the tax credit.
Flashboards have traditionally been a palisade of wooden boards inserted into the top of a dam's crest. Flashboards increase a dam's capacity to hold water. They are typically used seasonally in temperate climates, and are removed before winter. Flooding or even high water can wash flashboards away, impairing the dam's ability to hold water until they can be replaced. Replacing flashboards can entail danger to personnel, and it might be a long time before water levels recede enough to allow safe reinstallation. In the meantime, a dam's ability to safely store water can be reduced.
Inflatable flashboards allow operators to increase or decrease the effective height of the flashboard system remotely. The ability to quickly and safely restore pond elevation after a high flow event translates into increased electricity generation. For example, inflatable flashboards at the Deer Rips - Androscoggin 3 Hydroelectric Project on the Androscoggin River in Lewiston and Auburn, Maine, have been calculated as likely to increase electric generation by 4.56% compared to a historical baseline.
This incremental hydropower generation can be valuable to the dam owner. Not only does it allow the facility to produce more electricity, but it may also qualify the project for federal and state tax incentives. For example, Section 45 of the Internal Revenue Code provides a renewable energy tax credit to owners or operators of qualified renewable electric generation facilities. That credit was extended to the incremental production gains from efficiency improvements or capacity additions developed between 2005 and 2013. Developers can ask the Federal Energy Regulatory Commission to certify a historic baseline of power produced at existing dams, as well as the incremental increase in hydropower production due to qualifying investments. Once FERC has issued this certification, dam owners can provide that to the Internal Revenue Service to receive the tax credit.
Maine dam safety in question
Wednesday, September 7, 2011
Dam safety is an important issue. As Hurricane Irene demonstrated at the Marshfield Dam in Vermont last month, storms (and other conditions like earthquakes) place significant stresses on dams. When the stresses become too severe, the risk of dam failure increases, placing people downstream at risk. Some dams do not survive these conditions, such as Colcord Pond in Porter, Maine which blew out in March of 2010.
While the Federal Energy Regulatory Commission has jurisdiction over many aspects of most hydroelectric dams, states have asserted an interest in ensuring the safety of people and property near other dams and dammed rivers. Maine enacted a dam safety law in 2001 creating a safety inspection and enforcement program through the state Department of Defense, Veterans and Emergency Management. Under this program, dams are inventoried and categorized by their hazard potential, ranging from low hazard potential (minimal losses, primarily to the owner's property) to high hazard potential (misoperation or failure could “probably cause loss of life").
Investigative journalists recently revealed that the state was 2 to 7 years overdue for inspections of half of its high hazard potential dams, Records are missing for the inspection of other dams, and only 3 of the state's 24 high hazard dams were documented as being inspected on time. The journalists suggested that the state dam inspection office was severely understaffed for the workload required by the dam safety statute.
While the condition of many dams may not be known by the state, some dams' conditions are well-documented. A number of older reports have showed that many dams were deteriorating and nearing the end of their design life. Many of these dams do not have hydroelectric generation, but rather maintain a lake level. Many formerly provided mechanical power to people working at the site, in the form of waterpower harnessed under the riparian owner's mill privilege, but fell into disuse with the spread of fossil fuels and utility-provided electricity.
The condition of each dam, and what if anything should be done about it, is a fact-specific question that must be answered on a case-by-case basis. Different philosophies exist on how to protect public safety while respecting dam owners' private property rights. Nevertheless, the safety of Maine's state-jurisdictional dams is an important issue to consider.
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| Water spills over the Doughty Dam in North Berwick, Maine. This site provided power to numerous mills over the past centuries. |
While the Federal Energy Regulatory Commission has jurisdiction over many aspects of most hydroelectric dams, states have asserted an interest in ensuring the safety of people and property near other dams and dammed rivers. Maine enacted a dam safety law in 2001 creating a safety inspection and enforcement program through the state Department of Defense, Veterans and Emergency Management. Under this program, dams are inventoried and categorized by their hazard potential, ranging from low hazard potential (minimal losses, primarily to the owner's property) to high hazard potential (misoperation or failure could “probably cause loss of life").
Investigative journalists recently revealed that the state was 2 to 7 years overdue for inspections of half of its high hazard potential dams, Records are missing for the inspection of other dams, and only 3 of the state's 24 high hazard dams were documented as being inspected on time. The journalists suggested that the state dam inspection office was severely understaffed for the workload required by the dam safety statute.
While the condition of many dams may not be known by the state, some dams' conditions are well-documented. A number of older reports have showed that many dams were deteriorating and nearing the end of their design life. Many of these dams do not have hydroelectric generation, but rather maintain a lake level. Many formerly provided mechanical power to people working at the site, in the form of waterpower harnessed under the riparian owner's mill privilege, but fell into disuse with the spread of fossil fuels and utility-provided electricity.
The condition of each dam, and what if anything should be done about it, is a fact-specific question that must be answered on a case-by-case basis. Different philosophies exist on how to protect public safety while respecting dam owners' private property rights. Nevertheless, the safety of Maine's state-jurisdictional dams is an important issue to consider.
Vermont dam weathers Hurricane Irene
Tuesday, August 30, 2011
Hurricane Irene barreled up the East Coast of the U.S. this weekend, bringing high winds and heavy rain to a broad swath of the continent. About 5 million electricity customers lost power at some point during the storm's progress, with service still off for many consumers. Hurricanes and other storm events place added stresses on our electric infrastructure, resulting in not only power outages but possible dam failure.
In rain-lashed Vermont, utility Green Mountain Power worked to prevent the failure of the Marshfield Dam near the town of Cabot. Located on the Winooski River less than 20 miles upstream from Vermont's capital Montpelier, the earthen Marshfield Dam creates a 400-acre impoundment known as Molly's Falls Pond. Green Mountain Power uses the water impounded by the dam to run a 5-megawatt hydroelectric project.
Irene dumped a lot of water on Vermont. As a result, the water behind the Marshfield Dam rose within 10 feet of the dam's crest on Sunday night -- far too close for comfort. When the impoundment behind any dam gets too full, the dam is at increased risk of breaching; if a dam gets overtopped -- particularly an earthen dam -- this risk of dam failure is even greater. Dam failure at Marshfield could have serious impacts for the people and property downstream in the Winooski River Valley, from Montpelier further down. As a result, Green Mountain Power's emergency plan calls for a large controlled release of water through the dam once the water gets within 6.5 feet of the dam's crest. As a precaution, the utility asked the state emergency management agency to evacuate about 300 households in Marshfield, Plainfield, East Montpelier and Montpelier. Dam safety was at risk.
In the end, the water stopped rising, and then returned to a lower level. (Check out the USGS's streamflow data for the Winooski River near Montpelier.) Although Vermont suffered major damage from Hurricane Irene's remnants, the Marshfield Dam survived this storm.
In rain-lashed Vermont, utility Green Mountain Power worked to prevent the failure of the Marshfield Dam near the town of Cabot. Located on the Winooski River less than 20 miles upstream from Vermont's capital Montpelier, the earthen Marshfield Dam creates a 400-acre impoundment known as Molly's Falls Pond. Green Mountain Power uses the water impounded by the dam to run a 5-megawatt hydroelectric project.
Irene dumped a lot of water on Vermont. As a result, the water behind the Marshfield Dam rose within 10 feet of the dam's crest on Sunday night -- far too close for comfort. When the impoundment behind any dam gets too full, the dam is at increased risk of breaching; if a dam gets overtopped -- particularly an earthen dam -- this risk of dam failure is even greater. Dam failure at Marshfield could have serious impacts for the people and property downstream in the Winooski River Valley, from Montpelier further down. As a result, Green Mountain Power's emergency plan calls for a large controlled release of water through the dam once the water gets within 6.5 feet of the dam's crest. As a precaution, the utility asked the state emergency management agency to evacuate about 300 households in Marshfield, Plainfield, East Montpelier and Montpelier. Dam safety was at risk.
In the end, the water stopped rising, and then returned to a lower level. (Check out the USGS's streamflow data for the Winooski River near Montpelier.) Although Vermont suffered major damage from Hurricane Irene's remnants, the Marshfield Dam survived this storm.
November 9, 2010 - removal of the Brantley Dam, Virginia?
Tuesday, November 9, 2010
Today I'd like to comment on the story of the Brantley Dam on the Dan River in Danville, Virginia (about 4 hours west of Norfolk). This older dam once provided water to the now-closed Brantley Steam Plant. Over the years of changing ownership and possibly insufficient maintenance, the dam has recently become unpopular. Dam safety is a major issue, with 4 deaths since 1965 attributed to the dam.
The City of Danville Public Works department has issued a report recommending that the Brantley Dam be removed. The City is now considering removing the dam, and whether sediments trapped in the impoundment behind the dam may be toxic or polluted. The report suggests a variety of costs for dam removal, ranging from $90,000 for a "simple removal", $110,000 for a “staged removal" - or about $307,000 to remove the dam along with the entirety of the trapped sediments. Based on the relatively low amount of sediments, the report suggests simple removal is appropriate.
I'm curious to see what will happen with dam removal on the Dan River. A number of other dams exist across the watershed, some of which are privately owned, and at least one of which (at a water treatment plant) is a partially breached low-head dam - picture a 30' breach in the middle of a short, curving structure.
In this case, the dam played a role in energy generation, though not through hydroelectric capacity; rather, like the Briggsville Dam in Clarksburg, Massachusetts, it was built to provide a steady supply of water for industrial processes. In this case, the Brantley Dam supplied water to the steam plant electric generation station. As the economy of industrial production has shifted over the past century, the underlying factory or power plant may change its operations, leaving the dam without its original purpose. In Brantley Dam's case, the steam plant was ultimately shut down by the utility.
At some point, if the dam poses harms identified by society (safety at the Brantley Dam) without commensurate benefits, the dominant pressures may result in dam removal. In other cases, especially where hydroelectric production is possible, if dam removal is threatened absent improved fish passage, developers may find it worthwhile to maintain the dam in compliance with the regulations. In either case, it's a balancing act.
In Maine, last month I noted that the towns of Canton and Hartford were looking for ways to fund a dam repair project on Whitney Brook. This dam maintains the water levels in Lake Anasagunticook. The state had condemned the original dam, and the temporary dam needed repairs. In today's news, the towns have announced that the Maine Outdoor Heritage Fund has awarded them a $5,000 grant for the project. This fund is funded by designated lottery tickets, and can be used to acquire land and secure public access. One portion of the project includes a new boat launch and park, triggering eligibility for this grant.
October 26, 2010 - funding for dam rebuilding to maintain lake levels?
Tuesday, October 26, 2010
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| Fall foliage in the Basin, Phippsburg, above an old tide mill site. |
In the past, I've looked at issues relating to dams and the water level of their ponds and impoundments. For example, in March 2010, dam repair issues on Cobbosseecontee Stream resulted in a drawdown of Pleasant Pond by a foot or so. Then again, in September 2010, owners considered further dam repair on the Cobbosseecontee that would affect lake levels and users.
Today, a news item from Canton, Maine. A committee is exploring grant funding to rebuild a dam on Whitney Brook that maintains the water level in Lake Anasagunticook in Canton and Hartford.
The Dam Advisory Committee is now seeking funding to conduct an archeological survey in order to obtain a Community Block Development Grant. Currently, the old bridge piers remain in the river, while a temporary dam is in place. If the project is developed, the site will also feature both a boat launching site and a park.
Lake Anasagunticook's water level, and the steps taken to maintain that level, have been the subjects of some contention in recent years. This 10/30/2009 Kleinschmidt report describes the recent history of the situation:
Several dam safety issues with the existing structure and embankments were identified by the Maine Emergency Management Agency (MEMA) during a dam safety inspection by MBP Consulting in August 1997. Subsequent to issuance of the dam inspection report, MEMA issued a Dam Safety Order to undertake remedial actions to address the dam safety issues. The former dam owner did not comply with this order, dated December 4, 2006. On May 8, 2007, a Supplemental Dam Safety Order was issued by MEMA ordering that the four gates be left open until such time that an acceptable remedial action plan is implemented. Since that date, the gates have been open, thereby reducing the water level in Anasagunticook Lake by approximately 6-feet. The Town of Canton acquired the Anasagunticook Lake Dam through an eminent domain proceeding in 2008.
It will be interesting to see what happens on the lake, and what funding sources are available to support any development. Even for a project without any energy-related tax credits or incentives, Community Block Development Grants and other federal funding sources may be available for a dam rebuilding project to maintain lake levels.
August 31, 2010 - dam removal; biodiesel
Tuesday, August 31, 2010
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| Seen on the road: this soda distribution truck is "powered by BIODIESEL". |
I'm following the dam removal projects on the Elwha River on the Olympics Peninsula in Washington. One component of the $351 million river restoration project is the removal of two dams for about $40 million to $60 million: Elwha Dam (108' tall) and Glines Canyon Dam (210' tall). Glines Canyon Dam is located within the boundaries of Olympic National Park. This will be the nation's largest dam removal project to date.
Here's the National Park Service's website about the Elwha River Restoration project.
Dam removal is a hot topic. Arguments in favor of dam removal typically include safety, fish passage, and water quality problems caused by some dams. On the other side, arguments for keeping dams in place include mandates to generate local renewable power and flood control.
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