August 2, 2012
By Scott Lindemann
Water is an essential component of life on Earth, and comprises a portion of every living thing on it. Water is a solvent, surrounding organic molecules and allowing them to interact with each other in ways that allow metabolism, replication, and ultimately life. Water has a number of fundamental properties that make it crucial for life, including this solvent ability and its properties of cohesion and adhesion. Interestingly, more than 97% of the world’s water is found in the ocean as salt water, and of the remaining fresh water, nearly 70% is frozen in the polar icecaps or in glaciers. Given the vital importance of water to life on earth as well as its scarcity, it is surprising that some of available fresh water seems to be used irresponsibly.
Currently Los Angeles relies on water diverted from various lakes and rivers, with some water coming from as far away as the Sacramento and Colorado Rivers. In addition to these sources, groundwater is pumped from underground aquifers faster than natural processes are refilling them, meaning the possible loss of these sources of naturally filtered drinking water.
Drinking water can be condensed from seawater at desalination plants, but the evaporation of seawater is an energy intensive process. Water can also be purified from wastewater at treatment plants, but this too is energy intensive. However, even once this water is reclaimed it takes a lot of energy to pump it to consumers, making these two processes very expensive ways of obtaining fresh water.
Despite these sources of water, it seems to that Los Angeles is ignoring what is possibly the easiest source of fresh water: rainwater. When it rains in Los Angeles, water flows off the roofs of buildings and into storm drains, where it flows directly to the Hyperion Treatment Plant along with the wastewater. This is not only a waste of a resource, but actually creates a problem for the city’s water treatment plant as the increased flow of water must be processed alongside sewage water, sometimes doubling the total daily volume of water which must be treated.
One solution could be to simply retrofit buildings in Los Angeles with gutters to divert rainwater into local holding tanks. By doing this, the city would have a renewable source of water that could be used for irrigation or purified into drinking water more easily than wastewater could be, helping meet the demand for water and meaning that less water would have to be diverted from rivers, lakes, and aquifers. This water has also already been “pumped” against gravity and distributed as rain by solar energy, and so would not need to be pumped again. In addition, because this water would be stored instead of diverted into the sewers, it would ease the load on Hyperion on rainy days.
This small change will not solve all of Los Angeles’s problems, but it could be one step towards a better system.
About the author: Scott Lindemann is a fourth year student at the University of Southern Califonia. He enjoys reading, cooking, and lifting weights.