Denver, Colorado

Denver Water is the largest municipal water supplier in the Rocky Mountain region.  Most of its supply comes from mountain snowmelt.  The city has a large water collection and storage system to buffer against its highly variable streamflow supply.  A simplified climate change scenario shows Denver’s supply could be quite vulnerable to warming: a 2 to 5 degree Fahrenheit (1.1 - 2.8 degrees Celsius) increase in temperature could cause a 7 to 14% decline in water supply yield. An analysis of 400 years of streamflow, estimated from tree rings, shows droughts much worse than those in recorded history.  More detailed hydrological analysis for climate change is underway.

Denver Water is continuing to diversify its water resources through recycling, conservation and new supply programs.  The largest non-potable water recycling program in the region is being constructed.  A federal permit is being sought for a supply project to improve the system’s reliability.  For its Tap Smart conservation plan, Denver has budget $140 million over the next ten years.  A recent drought and water use restrictions reduced Denver’s use by 22%.  The utilities’ conservation goal is to maintain the same level of per capita use experienced under drought restrictions by using long term efficiency measures.   

Denver’s climate change adaptation plan includes 1) determining whether to increase its supply reserve to buffer against increased uncertainties, 2) preserving options and system flexibility to adapt to climate change, and 3) evaluating the benefits and limitations of conservation, recycling, and new supply development to determine the most robust portfolio.  An important adaptation consideration is that of using all of the efficiencies gained from conservation and reuse to supply growth could make the utility more vulnerable to supply shrinkage from climate change.