The term “drought” has been alluded to in a past blog about snowpack and streamflow but I didn’t explain it.  For some, drought means that it hasn’t rained for a few weeks.  For others, it means that the river’s runs dry.  Here in the Truckee Meadows, it could mean reducing water use by some percentage. It could mean a lot more.  

Regardless of where you live, drought can most simply be explained as an imbalance between available and needed water.  The imbalance can affect humans or ecological systems.  What does that mean for Nevada, the driest state in the US?  Our average annual precipitation is 10.3 inches.  In northern Nevada it falls mostly as snow, up to 12.85 inches in the northeastern part of the state.  In southern Nevada precipitation is 7.1 inches, mostly as rain.  There is large variation from year to year, as noted in previous blog on snowpack. 

The rapid rate of population growth in Nevada and expected increases in water demand heighten our susceptibility to drought.  Relationships between precipitation, rising temperatures, and the availability of water at the tap is complicated, with numerous lags, thresholds, as well as physical, social, and legal constraint and feedbacks.  The picture below shows most of the state experiencing at least “Moderate” drought.  Notice that the southern part of the state is experiencing “Exceptional” drought.     

From the National Integrated Drought Information System (NIDIS) for Nevada.

The description under exceptional drought is dire.  Besides a halt on fun activities, wildlife populations are in decline, ecosystem are threatened, citizens reduce water use, and reservoir levels are low, which limits power generation.  An imbalance between available and needed water can result in an imbalance between available and needed power.  This is all happening right now in Southern Nevada and surrounding areas.      

For the first time ever, the federal government may declare an official water “shortage” for seven states that rely on Colorado River water: Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.  This declaration is being prompted as Lake Mead levels are anticipated to fall below 1,075 feet for the first time ever in June 2021. Preparations have been made for lower-level water – new intakes have been constructed and power-generating turbines have been replaced at Hoover Dam.  

Interested in reading more? Get updates of drought in the west every Thursday at the US Drought Monitor.