The Fort Collins City Council adopted the updated Water Supply and Demand Management Policy (PDF 91KB) in November 2012. The policy states, "The reliability and capacity of the City's water supply system should be maintained to meet the planning level demand during at least a 1-in-50 drought event in the Cache la Poudre River Basin."

Fort Collins Utilities defines a drought as below-average runoff from the Cache la Poudre River. Droughts are measured by:

• Duration (or run length)
• Cumulative deficit below the average
• Average annual water shortage

Through statistical analysis, City officials determined the worst drought that could occur every 50 years in the region. This is called a "design drought". The Fort Collins Utilities staff uses the "design drought" to determine Fort Collins' current and future water supply needs. This "design drought":

• Lasts six years
• Has a run-off that is 550,000 acre-feet below average
• Has annual river volumes about 70% of the Poudre River's long-term average

Fort Collins Drought History
The graph below shows annual virgin (or native) flows of the Poudre River since 1884. Flows vary significantly from year to year. The green line on the graph denotes the long-term average.