Most people think of dams when they think of hydropower. Traditionally, the dams have been used in part to build up potential energy by piling up water upstream and convert it to greater kinetic energy by running the water through batteries of turbines. These structures have fallen out of favor as concern has grown as to their impact on wildlife, most especially as to salmon migration. As a result, there are many mitigation measures such as fish ladders and some dams have been eliminated altogether.
However, there is another alternative in the use of turbines for hydropower: placement directly into natural currents and tides. At this time, there are several initiatives to implement this design. One company, Hydro Green Energy out of Houston, is installing these turbines in the Mississippi River at Hastings, Minnesota and in the East River at New York City. Another company, Free Flow Power Corp out of Massachusetts, is planning to install turbines in the Mississippi River in Louisiana.
This new use of technology does bring its own concerns, especially with river transport. With dams, it is obvious where the hazard is and a set of locks may be provided in order to travel beyond the man-made obstruction. These turbines are underwater, however, and the water level changes over time. As a result, those operating river barges on the Mississippi are concerned that they may at some time run into the structures, thus both causing damage to each and disrupting a main artery of freight traffic. It is therefore uncertain as to whether or not the Louisiana project will be allowed to proceed.
Tags: civil engineering, hydropower, water
The Supreme Court recently upheld a permit issued under the Bush administration by the Army Corps of Engineers to allow a mining company to dump tailings from an Alaskan gold mining operation into Lower Slate Lake, which is located in the Tongass National Forest. The Clean Water Act is supposed to prevent such discharges into natural waters, which is essentially what the appeals court had said in its previous ruling that the Supreme Court has now overturned. Instead, the mining company, Coeur d’Alene Mines Corp, argued that the lake was the most practical and environmentally sound method of disposal. Though this is likely to kill all aquatic life in the lake, it was argued that the lake could always be restocked with fish and restored once mining operations had ceased. This claim seems suspicious to me, however, as gold mining operations have usually been associated with arsenic and I would suspect that such high levels would persist for some indefinitely long period of time. Nonetheless, the 6-member court majority had said that deference must be paid to the “reasonable” decision made by the Corps of Engineers. Unfortunately, what I read into this description is that one can get away with whatever the regulator can be convinced into allowing, however that might be accomplished.
Tags: Army Corps of Engineers, civil engineering, Clean Water Act, pollution, Reuters, water
In a May 8, 1984 file photo, Josephine Thompson, seated center, is joined on her porch by daughter Bernice Thompson, left, Michelle Clemmons and Vernie Akers, right, as floodwaters rise around her house in Martin, Ky., at the confluence of the Left and Right Beaver Creeks in Floyd County. Martin has flooded no fewer than 37 times since 1862 _ four in the past decade alone. Rather than give up on Martin, townspeople have enlisted the federal government in an ambitious project to rebuild it on higher ground. (AP Photo, File)
When do you just give up and leave? For one town in Kentucky, its when you have been flooded out about once every 4 years since 1862, including four times in the past decade alone. Martin, a coal mining town in the Appalachians, is being relocated to higher ground with the help of the Army Corps of Engineers.
I am not as familiar with Corps of Engineers programs as I am with FEMA, which has mitigation funding of its own that has been used for similar purposes. Specifically, the Flood Mitigation Assistance Program provides planning, projects, and technical assistance that is aimed at reducing the risk of loss within the National Flood Insurance Program (NFIP). Projects can elevate, acquire, or relocate structures. The way one may qualify is by suffering one or more flood-related losses greater than $1000 in value within a 10-year period. The community must participate in the NFIP and, though this is not clear, the property owner may have to have a flood insurance policy. This is just one more reason to get flood insurance, especially if you are anywhere near a stream and its floodplain.
Tags: Army Corps of Engineers, FEMA, floodplain, mitigation
The US government is looking at expanding a pioneering scheme in Flint, one of the poorest US cities, which involves razing entire districts and returning the land to nature Photo: GETTY
What is a city (or town) and its public utilities / services to do when half the population has left along with the factory(s) that used to employ them? In one of the most intriguing articles that I have read in a while, I had to learn from the London Telegraph that Flint, Michigan’s unique response was to initiate a program to bulldoze much of the city. In other words, they want to destroy a large part of the city to save the rest.
You might ask yourself why they would do this. The answer lies in the fact that expenses were not halved as the number of taxpayers were. Flint still had the same sprawling utilities and roadways to maintain, though only half as much is necessary. Policemen and garbage men have to cover the same area, though much of it is now empty. In fact, the empty buildings are decaying, detracting from any potential investment, and attracting criminal activity. In short, the remaining population only needs half the city that they currently have and are paying for. As a result, Flint is razing the empty buildings and returning the lots to nature. They are even looking to help relocate the few remaining holdouts of the most empty areas so as to build a more compact version of itself. As they do this, they can reduce the services and maintenance that is required and make the city more efficient and affordable for its remaining taxpayers.
I know that this is not necessarily an article about engineering, although it does apply to the utilities and roadways that engineers design and maintain. It is also a unique and intriguing solution that becomes more relevant as the economy causes more and more upheaval. I would not be surprised if a program like this would be of interest to some former textile mill towns here in North Carolina. Certainly the Obama administration thinks it is relevant as it seems to be looking to promote the idea to numerous localities across the country.
I would also like to note that this story of regression in Michigan follows up another story about 20 counties that have decided to grind up some of its asphalt roads into gravel. The reason for this is to reduce the costs of maintenance. Presumably there are also less people using them these days compared to when they were originally paved. In any case, I have heard people joke that the asphalt roads in Michigan had already naturally deteriorated into gravel due to lack of maintenance, which helped spur the development of so many SUVs from Detroit. At this, I will note that I, myself, have never been to the state.
Tags: civil engineering, development, London Telegraph, planning, roads, utilities
Time Magazine has a story about a request by the Army Corps of Engineers that the EPA and FEMA not disclose the location of coal ash ponds. It seems that the EPA and FEMA were assessing the hazard posed by these ponds after a spill in Kingston, Tennessee that covered 300 acres in sludge and destroyed or damaged 40 homes on December 22, 2008. Since then, it has been concluded that 44 of these ponds across the country, used to store waste from coal fire power plants, pose a high hazard to the surrounding public. After making this assessment public, the Corps of Engineers requested that the EPA and FEMA not disclose the location of these ponds, much as the National Dam Inventory had been removed from public access after 9/11. The reason for both of these moves is, of course, to make it more difficult for terrorists to identify good targets.
The problem with this approach of making hazards confidential is that it does nothing to remedy the original threat. The high hazard coal ash ponds and dams are still out there and people are still vulnerable with or without the aid of terrorism. Will anyone be moved to do anything about these hazards if the public does not know the danger they are already in? Admittedly, the high hazard status does not necessarily mean that these structures are an imminent threat to fail, but necessary supervision and maintenance is much easier to put off if the public is not aware of its importance. Doesn’t this more mundane and everyday threat trump the extraordinary one of terrorism? Moreover, would public knowledge lead to construction of fewer of these high hazard structures in the first place, thus making the terrorism concern moot in the first place? It’s something to consider.
Tags: Army Corps of Engineers, civil engineering, coal, dam, EPA, failure, FEMA, pond, Time Magazine
The story linked here details the costs (at least $29 million) and delays (at least 20 months) imposed upon a major highway and toll road project in Dallas, Texas by the levee that is to protect it. It seems to have been taken for granted that the levee along the Trinity River would be able to protect this major new piece of infrastructure that is to be placed behind it. However, the city has been instructed by the Army Corps of Engineers to verify the structural integrity of the levee before potentially risking the lives of thousands of drivers, especially in light of new and more stringent regulations in place after Hurricane Katrina. This appears to be a failure in planning, but it also calls to mind similar issues caused by levees.
FEMA requires that a levee have at least 3 feet of freeboard in order to remove the land behind it from the regulatory floodplain. The levee may have met this standard at the time of construction, but a new study may revise the floodplain elevation upward so that the levee no longer has the required freeboard. At this point, FEMA would have the Flood Insurance Rate Maps (FIRMs) changed so that the land once considered protected behind the floodplain is now in the regulatory floodplain. The effect of this is that mortgaged properties in this area will likely be required to obtain flood insurance. This may be costly and would likely both inhibit development and depress property values. The alternative is to upgrade the levee so that it, once again, has the freeboard required by FEMA.
The unfortunate part of the above situation is that FEMA has an all or nothing policy that does not recognize that the levee, assuming it is structurally sound, does still offer protection from events lesser than the regulatory 100-year flood. It assumes that the land behind this de-listed levee has the same flood risk as if the levee did not exist. A number of communities, many of which sit behind such levees that predate FEMA’s National Flood Insurance Program (NFIP), have become quite vocal about this policy and have pressured their Congressional representatives to change it.
The last thing I will mention here is the implications of a properly designed and maintained levee. There are costs here that are completely ignored. Specifically, though the event may be rare, a lot of damage will occur the moment the levee is breached. If the levee is 20 feet tall, it is likely that structures behind the levee would be flooded by at least 20 feet, which causes a lot of damage. Risk here is damage multiplied by frequency and results in the annual expected loss in dollars. The large amount of damage may offset the low frequency to result in a significant risk. Failure to account for this, along with the failure to account for structural deficiencies and maintenance issues, has contributed to the insolvency of the NFIP. Witness New Orleans after Hurricane Katrina.
Tags: Army Corps of Engineers, civil engineering, Dallas Morning News, FEMA, floodplain, infrastructure, levees
The New York Times has posted an opinion piece advocating for some important legislation regarding our nation’s infrastructure that has been lost in light of carbon trading, Supreme Court nominations, etc. This legislation would establish a national infrastructure development bank. The bank would use its own permanent fund to issue long-term, low-rate loans and bonds for the purposes of building road, public transit, drainage, water supply, flood-control, environmental mitigation, waste treatment and disposal, power, communications, and other projects. In short, it would make it easier to create and maintain all those things, seen and unseen, that keep our world going. This would be a great thing as the American Society of Civil Engineers (ASCE) rates almost all of these categories as a C- or lower in its annual report card due to a lack of investment. The ASCE doesn’t mention internet access, however, which is also much faster, cheaper, and more generally available in other developed countries. We have some catching up to do and this seems a good way to get there.
Tags: ASCE, civil engineering, infrastructure, New York Times
Lisa Jackson, center, head of the U.S. Environmental Protection Agency, tours IJburg, a residential district built on reclaimed land in Amsterdam, Netherlands, Tuesday May 26 2009. (AP Photo/Peter Dejong)
With the high cost of maintenance and the variability of its implementation, rising seas, and changing weather patterns, many are questioning the use of artificial flood control measures such as levees or dykes. Instead, flood control has come to mean either avoiding the floodplain altogether, or developing it in a way that accommodates the natural flood pattern. At least that is what has happened in the Netherlands, a place that was largely created by holding back the seas, and it seems that the Obama Administration may be coming around to the idea itself. Lisa Jackson, head of the US EPA indicated as much during a recent trip to the Netherlands. It also seems to be the thinking in Louisiana as this was the third trip that Senator Mary Landrieu (D-La) has made since Katrina. There has been no word yet if this means that New Orleans will be jacked up on stilts or made to float with the rising water, but it wouldn’t be a bad idea. In any case, the idea of restoring floodplains to their natural state has caught on with some US municipalities as shown in this testimony: Viewpoint: Protecting the Flood Plain.
Tags: civil engineering, development, EPA, floodplain
Construction workers used saws to remove the broken pipe alongside Bethesda's River Road in December. The 66-inch-diameter pipe had been placed directly against jagged rock instead of in the required bed of gravel. (Image By Sarah L. Voisin -- The Washington Post)
ASCE alerted me to this story in their latest news brief. It was a reminder as to why we do the things we do as engineers as well as the problems that we face with aging infrastructure. This 66-inch water pipe exploded under pressure. It is thought that installation next to jagged rock put undue stress on the pipe much as one would experience by having a knee pressed into one’s back. The pipe should have been over-excavated and placed on a bed of gravel. The wonder is that it took 44 years for this mishap to occur. I expect more such ticking time-bombs will come to our attention as they cannot escape the clock and our infrastructure isn’t getting any younger.
Tags: civil engineering, failure, infrastructure, Washington Post
I happened upon this gem last night. It is an episode of the PBS news magazine Frontline. It is a summary of what problems face our waters today. Primary examples of current threats include nutrients, endocrine disruptors, and PCBs.
Nutrients largely enter our waters from wastewater discharge and stormwater runoff contaminated with fertilizer and agricultural byproducts. However, combustion byproducts found in automobile emissions also contain nutrients and find their way into open water in significant amounts. These nutrients cause an explosion of microbial growth, which can reduce dissolved oxygen and kill everything that depends on it in the water, such as fish. In fact, the problem has gotten so bad that oceanic dead zones have spread across the world. One of the most famous occurs in the Gulf of Mexico around the Mississippi River delta. It is in order to stop these occurrences that stormwater best management practices (BMPs) are required as part of most urban development, but agriculture is still largely unregulated.
Endocrine disruptors are chemicals that mimic hormones in the body. They are used for this reason in drugs to treat certain conditions. It also happens to be that certain industrial products happen to have this property. A good example is bisphenol a (BPA), which is found in various plastics. It happens to be used in many drink containers and, for this reason, public pressure has forced many baby bottle makers to go BPA-free. The fear in this case is that boys will be femenized, possibly to the point of having fertility problems. When endocrine disruptors make it into the wild, it has been known to make organisms that are genetically of one sex to develop as the other. As far as I know, there is no current regulation of endocrine disruptors in our water (drinking, waste, or natural).
Polychlorinated biphenyls (PCBs) are an example of a kind of toxic and possibly carcinogenic chemical that is also very persistent as they do not readily degrade. PCBs are usually associated with old electrical facilities. Because they are so persistent, PCBs can accumulate over time in animals from both what they eat and their surroundings. Exposure can get worse from generation to generation as the PCBs can be passed from mother to baby. The effect is that an entire population could potentially be killed by PCBs. I have actually had the occasion to work on the design of road crossings of a stream contaminated by PCBs. It was necessary to span the stream so as not to disturb it and potentially release any PCBs that might be contained in the soils and sediment. The site has been designated a superfund site, though no cleanup has yet occurred.
If you watch the following video, it will take you through the history and the process by which Chesapeake Bay, Puget Sound, and other waters have been contaminated. It will also document the effects this has had on the ecosystem and some of the efforts that have been made to mitigate them. One obvious take-home message is: be careful where you fish. Another one might be to be careful what you drink.
Tags: documentary, PBS, pollution, water
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