A Dynamic Decision Support System for Drought Resiliency and Climate Change

A water utility is tasked with perpetually supplying water to its customers, regardless of weather patterns and water supply. Simply put, there is no room for a shortage under any conditions. This can be most challenging in times of drought, when available water is slim and the utility system is most stressed. Across the west, these drought planning challenges are further exacerbated by ever increasing water demands, and a changing climate may be accentuating weather variability and drought severity. However, given information about plausible future conditions, it is possible for a water purveyor to evaluate management strategies and system limitations.This study develops a decision support system (DSS) structured for the Truckee Meadows Water Authority (TMWA), northern Nevada’s largest water purveyor. The DSS has been created to assist in long-term drought planning, and is able to identify situations when existing infrastructure or policies are insufficient to meet customer demands under drought conditions. The model uses a linear program, to solve the water supply and demand problem via a cost minimization algorithm. The model has been parameterized with current operating conditions, and is easily adjustable to analyze the effects of system upgrades or policy changes.The model has been used to evaluate two drought scenarios, created by a partner project titled Water for the Seasons (USDA/NIFA Grant No. 1360505/1360506). Both scenarios are based on the same concatenation of two historic droughts, creating a 13-year dry period. One has been calibrated to current temperature profiles, and the other to projected temperatures for the time period 2051-2070. Results show that utility operations are drought resilient for both scenarios, but substantially more stressed under the future drought conditions; due to a shift in the timing of snowmelt and runoff.. Dynamic monitoring of snowpack and drought conditions could help to ease future difficulties, with the most beneficial actions related to the timing of reservoir storage accumulation. TMWA’s current drought response plan was seen to be adequate for the near future, but with the potential to be explored further for greater drought resiliency