Guajataca Dam, spillway erosion, and repairs

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.

Oroville Dam evacuation and relicensing

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.

Susquehanna River flooding threatens dam, communities

Close on Hurricane Irene’s heels, the remnants of Tropical Storm Lee are dropping up to 10 inches of rain across the northeastern United States.  As we saw when Irene hit Vermont, storms like this can cause not only widespread flooding as streams rise above their banks, but even risk dam failure and more catastrophic flooding.

Now, the rains caused by Tropical Storm Lee have led authorities from Maryland to New York to order the evacuation of nearly 100,000 people.

Flooding along the Susquehanna River is responsible for a large portion of this risk.  Arising out of branches in upstate New York and western Pennsylvania, the 464-mile long Susquehanna is the longest river on the east coast to drain into the Atlantic Ocean.  The river overtopped retaining walls in Binghamton, NY earlier today, leading to road closures that effectively isolate the city.  Downstream, deepening floods have caused the evacuation of the entire city of Wilkes-Barre, PA.

The Susquehanna flooding has also impacted the Conowingo hydroelectric dam about 10 miles above the river’s mouth in Maryland.  With 11 turbines providing a nameplate capacity of 572 megawatts, the Conowingo dam is one of the nation's largest non-federal hydroelectric facilities.  Now operated by Exelon subsidiary Susquehanna Electric Company, the Conowingo Dam is threatened by the Susquehanna floodwaters.  As a result, 50 of the dam’s 53 flood control gates have been opened, causing authorities to evacuate people from the downstream communities of Havre de Grace and Port Deposit.  Area residents remember 1972's Hurricane Agnes, whose rains and flooding caused all 53 flood gates to be opened and the dam operator to prepare for a controlled breach of part of the dam.

As Lee’s rains move out of the area, water levels in the Susquehanna River will peak and then recede.  Time will tell how damaging the flood waters will be.         

Maine dam safety in question

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.

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

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.

January 10, 2011 - Ballville Dam removal; Lake Erie wind

As many dams in America are approaching their centenary years, dam owners face pressures to maintain or upgrade their infrastructure to comply with safety or environmental regulations - or else face dam removal.  Located outside Fremont, Ohio, the Ballville Dam now faces this choice.

Constructed in 1911, the Ballville Dam was built on the Sandusky River about a dozen miles upstream from Lake Erie to impound and direct water into a downstream hydroelectric station.  The dam is 34.4 feet high and over 300 feet long.  In 1946, the downstream hydroelectric facility ceased generation.  In 1959, the city of Fremont bought the Ballville dam for water supply.  In the ensuing 50 years, issues including upkeep and maintenance costs for the dam led the city to create an alternative reservoir to replace the dam.  The dam has been implicated in fish passage problems, and its removal is anticipated to open up over 22 miles of habitat to gamefish like walleye.  The dam has also been implicated in problems with ice jams above Fremont.  All this, without a revenue stream from the dam, has led Fremont to work towards dam removal.  Fremont has since won approximately $6 million dollars in grant funding to support dam removal, which is slated for summer 2011.


If the dam is removed, large amounts of backed up sediment - including a contaminant burden of heavy metals and polyaromatic hydrocarbons - will either come with it or be swept downstream into Lake Erie.  A report suggests 350,000 cubic meters of sediment may need to be removed to establish the channel of the Sandusky River through the impoundment.  However, the report suggests that the sediment pollutant concentrations are less than or equal to those in existing Lake Erie sediment, and thus that mixing with the lake would dilute any effects.

Interestingly, the Ballville Dam has faced trouble before.  Two years after its construction, the dam failed due to poor anchoring into the sediment, causing serious flooding in Fremont.  Today's dam was rebuilt using a stronger foundation. In 1913, the dam served a useful purpose: supporting the nearby hydroelectric station.  In 2011, without that support for hydroelectric generation, will the Ballville Dam be removed?

Meanwhile, on Lake Erie, the Lake Erie Energy Development Corporation continues to make progress toward the nation's first inland offshore wind development: five wind turbines in state waters about 7 miles off Cleveland.  Great Lakes wind offers many of the advantages of both terrestrial and oceanic wind, while posing other challenges.  Will the Lake Erie project be the first to reach success?

October 28, 2010 - Maine dam removal?

Fiery fall foliage in Phippsburg, Maine.

Yesterday, I mentioned a list of recently-removed Maine dams.  That list describes 20 dams as having been removed as of January 1, 2010, with another ten dams described as "currently proposed or under study for removal":

*	Boston Felt Dam	Lebanon, ME & Rochester, NH	Salmon Falls River
*	Coopers Mills Dam	Whitefield	Sheepscot River
*	Gardiner Paperboard Dam	Gardiner	Cobbosseecontee Stream
*	Great Works Dam	Old Town & Bradley	Penobscot River
*	Montsweag Dam	Wiscasset & Woolwich	Montsweag Brook
*	Veazie Dam	Veazie & Eddington	Penobscot River
*	West Winterport Dam	Winterport & Frankfort	Marsh Stream
*	Juliet Mill Dam	Lisbon	Sabattus River
*	Farwell Mill Dam	Lisbon	Sabattus River
*	Martin Brook Upper Dam	Madawaska	Martin Brook

Of these, several more have been removed.  For example, the Montsweag dam is gone.  The West Winterport dam is also gone.

Let's take a deeper look at one of the dams on this list.  The Boston Felt dam (Project No. 4542–013), which formerly produced 150 kW, was granted an exemption from licensing on August 29, 1983 (24 FERC ¶ 62,240). The project stopped operations in May 2006, due to a breach of the project dam by high river flows.  Project owner Bacon Felt Company, Inc., stated that a 20-foot long, 6-foot wide section of the wooden frame dam was carried away by the flooding.

After the water level dropped, the Federal Energy Regulator Commission ordered the owner to repair the dam.  US Fish and Wildlife Service also gave a directive regarding the installation of fish passage.  The owner allegedly explained why the project was inoperable (damage to the dam) and told FERC that resumption of generation at the project may be beyond its available resources, and said it would file a compliance plan and progress reports.  By September 2009, FERC issued a notice of revocation of exemption by surrender, based on allegations that exemptee had not taken responsive action.

In an October 2009 response, Bacon Felt filed a protest, stating that it had in fact replied to the Commission's information request and had requested a 120-day review period.  By February 2010, the project owner filed a formal motion requesting withdrawal of the notice of revocation of its exemption to maintain the project.  Bacon pointed to a host of changes, including a change in ownership of the company, changes to their manufacturing strategy, and an overall increase in the price of purchased power.  Bacon then argued that it had not surrendered its exemption, nor had it abandoned the project triggering an implied surrender.  Bacon pointed to examples of what implied surrender usually looks like, including:

• James Lichoulas Jr., 124 F.E.R.C. ¶ 61,255, P 23 (implied surrender found where “the building over the substructure generating facilities [had] been demolished, the generating equipment [was] covered with collapsed building materials, and the wicket gate operators of the turbines appear[ed] to be inoperable.”), on reh’g, 125 F.E.R.C. ¶ 61,195 (2008)
• New England Fish Co., 38 F.E.R.C. ¶ 61,106, at 61,285 (1987) (finding surrender where the licensee “abandoned good-faith operation of the project in 1964” and “never filed an application for new license when the term of the original license expired in 1977.”)
• Pinedale Power & Light Co., 38 F.E.R.C. ¶ 61,036 (1987) (finding surrender where the licensee abandoned the project 15 years prior to the surrender decision and sold the property 12 years prior to it).

Bacon then argued that current energy policy still favors the development of suitable waterways, and that it could continue (or resume) producing low-cost renewable power from the project.

The case remains pending before the Commission.

September 10, 2010 - Cobbossee dam repairs

Dam repairs pose interesting technical, environmental, and social challenges.  The situation with the Cobbossee Outlet Dam, in the town of Manchester, Maine, provides a good example.

For your reference, here is a Google map of the dam site.  This is several miles farther upstream from the New Mills Dam in Gardiner, which had its own dam repair and drawdown issues this spring.

The Town of Manchester owns the dam, which maintains the water levels in 5,000-acre Cobbossee Lake above, as well as ensuring adequate flows in Cobbossee Stream below the dam.  In all, parts of six municipalities are affected by the waters of Cobbossee.  The dam is damaged: one of its six gates is currently boarded up because it was at risk of failing.  Rotting wooden timbers need to be replaced, possibly with galvanized steel beams.

To perform the repairs, the lake level may have to be drawn down.  This concerns boaters on the lake, who fear that the drawdown might end the boating season early.  To address this concern, the plan is to do the dam repairs during this fall's annual seasonal drawdown of the lake.  Many dam managers perform drawdowns in the fall for flood control and to make room for spring runoff. 

Cost and cost-sharing are also at issue.  Currently, as the dam owner, Manchester appears to be on the hook for the repair costs, although there is talk of asking other communities along the watershed to pay into a repair fund.  It will be interesting to see how the project progresses.

September 2, 2010 - sewage digestion; dam damage

In August, news covered the plans of the Lewiston-Auburn Water Pollution Control Authority to build a anaerobic digester plant at its sewage treatment facility.  The plant would reduce the Authority's solids disposal costs and could generate significant energy from the methane produced.  Now, the Lewiston Sun Journal says they're clarifying that it is "not a given" that the Authority will develop the project.

Hydroelectricity: a rock has fallen onto the Ennis Dam on the Madison River in Montana.  Here is a map of the Ennis Lake and gorge area.  You can see pictures here and a map here.  It looks like Ennis Lake will be drawn down 5' to relieve some of the back-pressure on the dam, and then later draw it down another 4' for a full inspection and possible repairs.  Ennis Lake only averages 8'-9' deep, so this drawdown will have noticeable effects -- if not as permanent as the effects of drawdown prior to breach.  Hopefully the drawdown will not cause landslides and erosion as at Fort Halifax on the Kennebec River in Maine.

What's it like behind the gates of Bath Iron Works?  This Working Waterfront piece gives a good description of a tour of the large defense contractor on the Kennebec River.