Damned Dams

Dams have been supplying water and controlling floods for hundreds of years. But what happens with they fail?

In 1889, the Johnstown dam in Pennsylvania broke, killing over 2,200 people. Above is an illustration of the break and a picture of the devastation. Currently, roughly 5% (or 4,400) of dams in the US are considered safety hazards.  Fixing these dams would cost billions of dollars, money that we don't have. Therefore, in order to deal with these comprised dams, officials have reduced holding levels and developed evacuation plans.. After the Gulf oil spill, I'm not convinced these interim measures are enough. A huge unexpected storm (the result of climate change, of course) could open the floodgates.

From an environmental standpoint, the construction of dams was a horrible idea. They disturb essential habitat and block paths for fish like salmon, which swim up river to reproduce. They disrupt natural erosion and sedimentation cycles, destroy wetlands, and alter temperature regimes.

However, dams made place for cities to flourish, and if they were to break, thousands of lives would be at risk. Also, the billions of gallons of water released from a break would not only carry an enormous amount of debris and sediment but also accumulated lead, mercury,  PCBs, nitrogen, and (guess what.) invasive species. The environmental consequences could be devastating to areas downstream, and a return to the ecosystems of old may be impossible. However, it has been shown that dam removal can help restore wetlands, temperatures, and salmon pathways.

So, do we remove the dams? Do we wait for something to happen? Or, do we fix them?

Drought in the Southwest

A few days ago, the New York Times posted an article about the 11-year drought that has been occurring in the Southwest. Lake Mead, on the Colorado River, has a water level only 15 inches above its lowest recorded minimum in 1956. From Las Vegas to Los Angeles, water prices have skyrocketed, water use restrictions have been tightened, and people are starting to feel the pain. Now, in order to relieve the stress on Lake Mead, they’re considering releasing water from Lake Powell, also on the Colorado River, so that it flows into Lake Mead. The map below is kind of hard to read but Lake Mead is at the southern tip of Nevada, and Lake Powell is in southern Utah.

Right now, 70% of water use can be attributed to outdoor activities. While some of this is legitimate, i.e. irrigation of crop growth, a lot of that is pure landscaping. Word of advice: if you want a luscious green lawn, move somewhere NOT in the desert. I know you want your yard to be just as pretty as your neighbors, but for the good of everyone, please don't fall into the tragedy of the commons. I really don’t understand the population boom in the Southwest. It’s a seemingly uninhabitable environment that we humans decided we should make habitable. The thought: why should we adjust ourselves to the climate when we can simply adjust it to fit our needs? It’s a perspective that I’m sure will change once the water crisis felt around the world finally hits America hard. The drought in the Southwest? Not bad enough.

Nationally, agriculture is responsible for 80% of our water use. What are some ways to address that? I would like to advocate vertical farming, if not simply as an effort to conserve water. A vertical farm is basically a bunch of greenhouses stacked on top of one another. They use technology like hydroponics, which requires 70% less water than conventional agriculture, and aeroponics, which uses 70% less than that. There are other benefits too. In addition to having a small physical footprint, vertical farming is indoors, which makes it relatively immune to weather variation, such as droughts and disease/pest invasion. Furthermore, biogas digesters and living machines can be employed to convert waste into usable resources, including methane for energy. Vertical farming isn't without downsides, however. The daylighting and heating needed to farm indoors requires a lot of energy. About half of the energy can be covered by biogas digestion, but the rest will need various energy sources, like solar and wind, to keep farming economical and sustainable.  I could say more, but I won’t. Instead, if you want to learn more about vertical farms, I’m going to add a long spiel about them under “Favorite Concepts”.

Hydroponics

Aeroponics

Dickson Despommier, a professor at Columbia University, is the field's all star. Here's his website.