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.

Sea level rise and coastal LNG terminals

Should federal agencies consider climate change and sea-level rise as they review the environmental impacts of liquefied natural gas terminals?

Yes, according to letters recently filed with the Federal Energy Regulatory Commission by the Sabin Center for Climate Change Law.  Last week the Columbia Law School center submitted comments on two cases involving applications to develop liquefied natural gas export facilities in Maine and Louisiana.

Pursuant to the National Environmental Policy Act (NEPA) and its implementing regulations, in approving an activity, the Commission must consider reasonably foreseeable indirect and cumulative environmental impacts of that activity.  Each case targeted by the Sabin Center involves a proposal to develop facilities for the liquefaction and export of natural gas from coastal or riverine sites: 

• Downeast Liquefaction, LLC has proposed the Downeast LNG Import-Export Project, to be located in Robbinston, Maine.  The bi-directional terminal on the banks of the Passamaquoddy Bay would be capable of processing an average of approximately 300 MMcf per day of pipeline-quality natural gas (including fuel and inerts) in the liquefaction mode and 100 MMcf per day in the vaporization mode.

• Louisiana LNG Energy, LLC has proposed the Mississippi River LNG Project, to be located in Plaquemines Parish south of the Port of New Orleans.  The project would have an initial capacity of 2 million metric tonnes per annum (MTPA), with a targeted start-up in late 2017.

Procedurally, each of these cases is at the stage where the Commission solicits comment on the scope of issues it should include in its environmental review.  In similar letters filed in each docket (Downeast and Louisiana), the Sabin Center took no position on the export of liquefied natural gas or on whether the project should be approved. Instead, the center noticed that while the Commission's Notice of Intent to prepare an environmental impact statement included many important issues to consider, the notice did not identify the potential impact of climate change on the LNG project.

Specifically, the Sabin Center's letters note that sea level rise, and an associated increase in flooding and storm surges, may pose a significant risk due to the project sites' coastal location.  The letters argue that NEPA requires the Commission to assess the projected range of sea level rise and storm surge throughout the life of the projects and identify ways to prepare for climate change-related risks.  They also called for requiring the projects' design to incorporate an additional margin of safety, known as “freeboard,” to account for unanticipated risk factors that can contribute to flood heights, such as waves and the effect of development on ground water absorption.

Whether the Commission will agree with the Sabin Center remains to be seen.  As federal agencies issue permits for energy projects, they face increasing pressure from the public -- and presumably from the administration -- to consider the projects' broader implications for and from climate change.

Maryland dam faces sedimentation threat

In September 2011, Tropical Storm Lee caused flooding in the mid-Atlantic region.  The Susquehanna River rose far above its banks, causing disruptive floods in Pennsylvania and Maryland.  Near the river’s mouth into Chesapeake Bay, massive flooding threatened to breach the 572-megawatt Conowingo Dam.

With its flood gates wide open, the dam survived the flooding.  At peak flows, about 7 million gallons flowed through the dam every minute.  That water transported millions of tons of sediment from the Susquehanna watershed out into the bay, along with large amounts of trash and debris.

The impacts of the flood are still being assessed.  Under typical operations, the dam builds up about 2 million tons of sediment every year, or about two-thirds of the Susquehanna River's total sediment burden.  (Compare the dams currently being removed from the Elwha River in Washington, which had trapped an estimated 24 million cubic yards of sediment.)  Overall, four dams on the Susquehanna might hold up to 280 million tons of sediment.

While Lee removed several years' worth of sediment from the Conowingo Dam, more sediment builds up every year.  The Army Corps is concerned that the Susquehanna River dams have nearly reached their full capacity to hold sediment, and is launching a project to study what could be done, such as sediment dredging or remediation.

August 20, 2010 - Korean tidal power

Today, a quick look at tidal power development in Korea.  The 254 MW Sihwa Lake Tidal Power Plant in South Korea is scheduled to be ready to run as early as this December.  When it does, it will become the largest-capacity operating tidal power plant in the world, as it will dethrone the 240 MW Rance Tidal Power Station near Saint-Malo in France.

Sihwa Lake was formed in 1994 by the construction of a seawall to impound fresh water for agriculture and to help mitigate flooding.  However, as the impounded water became more and more polluted and thus useless for agriculture, the country responded by allowing seawater to flow in in 2004.  To develop the tidal power resource, the developer installed ten submerged bulb turbines into the tidal barrage.  These 25.4 MW turbines run when the tide floods in; the tide drop does not produce power in this configuration.  While this may be less efficient than an ideal scenario in which flows are more controlled and harnessed in both directions, this unpumped flood-based power production mechanism balances energy against other policies like land use and conservation.

Sihwa Lake isn't Korea's only tidal power project in development.  Daewoo has signed a contract for an 812 MW tidal barrage near Ganghwa Island; this project is scheduled to be completed in 2015.  Closer to islands west of Incheon, the government is exploring a 1,320 MW tidal power station for later this decade.

July 30, 2010 - what is PACE financing?

Solar energy in action over Bush Key in the Tortugas, off Florida.

Today, a look at a tool that can be used to help finance renewable energy or energy efficiency projects: PACE.

What is PACE financing?


PACE, short for "Property Assessed Clean Energy", refers to one policy mechanism available to support the development of more renewable energy and energy efficiency projects. Essentially, a property owner can borrow money (often at low rates through municipalities) to develop the project; the property owner then pays back the loan through your property tax bills over a long time (often 15 to 20 years). If the property changes hands, so do the energy improvements -- and so does the PACE loan obligation.


This idea, which started in Berkeley, California, is one way to help finance renewable generation or energy efficiency retrofits. Municipalities can raise money through bond issues, generally with no recourse to the municipality. PACE thus represents a new twist on an old tool: land-secured special financing districts.

Landowners like PACE too. Repayments are designed to have a smaller footprint than the cost of the energy saved; homeowners or businesses thus see their expenses go down, even while spending capital to improve their building energy efficiency.

One challenge that has arisen is that mortgage-market megaplayers Fannie Mae and Freddie Mac have expressed concerns about the security of PACE loans because they aren't necessarily subordinate to mortgages. Existing lenders are worried that landowners' PACE obligations to municipalities may trump lenders' mortgage interests in the property. This may be easy to fix, as Maine has done by making PACE loans subordinate to existing mortgages. However, without federal-level action (and the Senate energy bill doesn't include PACE at the moment) the lenders' resistance is throwing a bit of a wet blanket on the opportunities posed by PACE.

Here's an interesting High Country News article about dams in the American West, covering issues including dam failure and flooding, dam removal, fish passage, and energy policy.

July 21, 2010 - balancing wind into the grid; underperforming community wind turbine; China's Three Gorges Dam flooding

License plate seen in Maine:

From Energy Policy Update

How much wind can we really integrate into today's power grid? An interesting article in the Oregonian highlights the challenges. Take, for example, what happened on May 19, when the wind shifted and Bonneville Power Authority grid operators had to make room on the wires for 1000 turbines' worth of wind (nearly 2000 MW). This is a lot of power: more power than the BPA control area needs, more than the amount of hydro production that could be ramped down, and more than BPA could export to neighboring control areas. So what did BPA do? It told wind generators to feather their blades and cut their production -- a less than ideal solution.

In a parallel scenario, Venezuela is undergoing rolling blackouts. Venezuela relies on hydroelectricity for 70% of its power, and a long-lasting drought has crippled power production. Critics also point to chronic mismanagement and underinvestment by the nationalized companies that operate the power grid.

The City of Saco, Maine, is in a bit of a pickle over its community wind project. Back in 2007, Saco bought the turbine and tower for $207,000 from Entegrity Wind Systems. (As mentioned in an earlier blog post, Kittery also bought a turbine from Entegrity. It did better than Saco's, but Kittery's turbine underperformed as well.) At the time, community-scale wind was all the rage. The Maine Legislature had directed the Maine Public Utilities Commission to organize a stakeholder process to evaluate the state's opportunities for community wind. Although this process ultimately resulted in a report concluding that community wind was not generally economic under current conditions, many people and communities decided to pursue small- and medium-scale renewable project for their civic, educational and environmental values.

When Saco bought the turbine, Entegrity told Saco that the unit would generate 90,000 kilowatt-hours annually (about $12,600 worth of electricity) for 10 years. The unit came online in February 2008. It never performed as well as Entegrity had represented. At some point, former Entegrity head James Heath offered to buy the turbine back for $130,000. Then the turbine broke. In the meantime, Entegrity Wind Systems went bankrupt. The City was left holding the underperforming turbine.

Now, the Saco City Council is considering its options. Repair the turbine? Sell the turbine? Negotiate with James Heath? Litigation?



In other news: China's Three Gorges Dam is facing record flooding, comparable to the 1988 floods that killed over 4000 people. The dam had been touted as offering protection against floods. So far the dam is holding, but the massive reservoir is within 20 meters of full. More water is on its way.

A new report by the Maine State Chamber of Commerce and the Maine Development Foundation suggests that Maine businesses' most critical challenges come from health insurance costs, energy, taxes, regulations and transportation, in that order. A Lewiston Sun Journal editorial calls for an end to "destructive regulatory practices" that drive money, businesses and people out of Maine.

WCSH 6 reports on the plans of Ocean Energy Institute founder Matt Simmons to transform Maine into the "Silicon Valley of ocean energy". The Ocean Energy Institute has previously expressed interest in exploring links between offshore wind and ammonia production for energy storage.

July 9, 2010 - Smelt Hill Dam

A peek at part of the New Meadows quahog fleet:



Today, I begin a look at Maine's first hydroelectric dam: the Smelt Hill dam on the Presumpscot River in Falmouth. Dammed in 1735 and with generating capacity installed in 1889, the Smelt Hill dam was the first hydro dam to be built in Maine.

In the early 1700s, the land around the Presumpscot River's mouth was owned by Thomas Westbrook, William Pepperell, and Samuel Waldo. Town records show that "a great dam" and sawmill were constructed on the lower falls in 1735. Resource conflicts began immediately, with upstream fish passage so impaired that Chief Polin, leader of the "Rockameecook" Tribe of Abenakis made the multi-day journey to Boston to ask Governor Shirley to require fish passage on all dams on the Presumpscot system. Accounts from the era describe “an acre of fish, mostly salmon” penned up below the impassable dam.

In 1726, George and Judith Knight settled on the Middle Road in Falmouth. Descendant Samuel Knight became known as the "Smelt King", famously claiming that if you laid his smelt catch end to end, it would reach all the way to Bangor. Perhaps thanks to his marketing pitches, the area came to be known as "Smelt Hill."

In 1889, the S.D. Warren Company erected a powerhouse (and new dam) at the site to supply electricity to its paper mill several miles upstream in Westbrook. The March 15, 1896 edition of the Electrical Journal gives a contemporary description of the power station:

The power plant of S. D. Warren & Co., at Smelt Hill, Maine, on the Presumpscot, has been started up for the first time. This plant was built some six years ago when the dam at the lower falls of the Presumpscot was constructed. The plant is arranged for twelve large turbine wheels. It has laid idle all this time, but recently the company has secured the right of way on the bank of the Presumpscot to Westbrook and has run a line of heavy copper wires whereon to convey the power from the new plant to the big paper mills. The distance is some five or six miles. The reason that this power has at last been transferred up the river and put into use is because of the lack of water at times to furnish sufficient power at the paper mills. They are now using only two of the turbine wheels at the Smelt Hill plant, but next week will use four of them.

It's interesting to see that even in the late 1800s, developers had a hard time getting easements to string transmission and distribution lines from distributed renewable resources to markets and loads.

By its end, Smelt Hill was the site of a 151-foot long, 31-foot wide and 15-foot high stone filled, timber crib dam, along with some associated structures. Smelt Hill Dam was not operational between 1943 and 1985. The Town of Falmouth's 2000 Comprehensive Plan documents the Smelt Hill dam as having been "damaged beyond repair in a 1996 flood." The 1996 flood -- almost 20 inches of rain in 3 days -- on the Presumpscot rendered the hydroelectric facilities and the fish lift at the dam inoperable and anadromous runs again ceased on the Presumpscot.

The dam was subsequently removed in October 2002. In a coming edition, I'll look at the issues that led to its removal.

Source note: much of the history of the area is drawn from the National Park Service's 1993 Historic American Engineering Report for the downstream Presumpscot Falls Bridge.



News: retired U.S. Navy Vice Adm. Dennis McGinn, vice chairman of the CNA Military Advisory Board, an retired-officer based energy and climate change think tank, visited Maine to call for greater energy independence.