Which type of conservation is effective?

This is a great Q and A with Brian Richter, a freshwater scientist with the Nature Conservancy. He makes some well-needed points about water conservation in major cities in the US, and which steps might actually make a difference.

Richter points out that recycling "gray water," or water that has been used previously for laundry or bathing, to use for lawn irrigation is actually taking that water from the freshwater source. Water that runs through our faucets and returns down the drain actually returns to the source after treatment at a municipal water plant, starting anew in the water cycle. 

However, some water IS lost through use and does not return to the freshwater source. 10 to 20% of water doesn't return to the freshwater source, and that's the water we use for irrigating our green lawns. It gets evaporated, or "depleted," as Richter says.

So while retrofitting your house with water-efficient appliances may reduce the water you use for daily activities such as laundry and dishwashing, it doesn't ultimately change water conservation, or help cities facing a water crisis unless it is so severe there is not enough water in the cycle to hold over through the treatment cycle. 

Photo credit: http://ow.ly/mfcUF

That's why cities need to focus their efforts on xeriscape. Using precious water to turn the brown prairie green is the definition of waste. Denver is without dispute running out of water, as Governor Hickenlooper's office projects a statewide gap of 500,000 acre feet by 2050. That's the equivalent of what 5 million people use in a year. Which also happens to be what the entire state of Colorado uses in a year. In forty years, we won't even be able to support the state's current population, and that's before we take into account population growth.

Leaving the tap running while you brush your teeth is one thing. Trying to turn the desert into a lush, green paradise is another. We need to wake up, and conserve where it really matters.