The new Colorado River Cooperative Agreement between western water interests and Denver Water is laudable and a great step forward, but lost in the hoopla is the simple fact that Denver Water still plans to build an unnecessary $576,000,000 expansion of Gross Reservoir in Boulder County. A simple back-of-the-envelope calculation shows that installing low-flow shower heads for every resident of the Denver metro area would be cheaper, would save more water, and would have the added benefit of being environmentally sound.
The projected shortfall in Denver by 2030 is only 18,000 acre-feet of water, but let’s be generous to Denver Water and assume the shortfall is double that value at 36,000 acre-feet or about 12 billion gallons. Using 2.5 versus 6 gallons per minute, low-flow shower heads save about 35 gallons in a ten minute shower. At one shower per person per day with 2.5 million residents in the Denver metro area, that saves about 32 billion gallons per year. Of course, many folks in Denver have already installed low-flow fixtures, but these figures show that only about a third of the residents would need to install low-flow shower heads to make up the projected shortfall. And remember, we were being generous to Denver Water, so the real value is closer to one-sixth of the residents.
The cost? Forget that only a fraction of the households need new shower heads. Instead, let’s buy all 2.5 million people very nice $100 shower heads and allow an additional $100 for installation. Total cost: $500,000,000. This rather magnanimous payment is still cheaper than the proposed Gross Reservoir expansion.