Risk Management2 | 2021 SECURE Report Web Portal

Risk Management Strategies

Actions to manage risks to water users from variations in hydrology, including risks from floods, droughts, and water supply variability

Proactively preparing for and better understanding drought risks are strategies that can build resilience as the severity, duration, and frequency of drought increases. Severe droughts can last decades, like the one in the Colorado River Basin, where a historic drought has continued since 2000, and Reclamation’s September 2020 modeling results indicate increased likelihood of reaching the first ever declared shortage conditions in the Lower Colorado River Basin before 2025 if the drought persists.

In recent years, Washington State has had record low snowpack followed by hot, dry summers resulting in “snowpack droughts” which pose challenging conditions for communities, farms, and the environment.

After the most extreme drought in recent decades, the Washington State Department of Ecology updated its 1992 Washington State Drought Contingency Plan under the WaterSMART Drought Response Program in 2018. This new drought framework prioritizes early action before water supplies reach critical levels and identifies multiple drought indicators.

Historically, reliance on the State’s legal definition of drought limited agencies from taking certain actions until water supplies were less than 75 percent of normal and hardship to water users was anticipated. In the spring of 2020, the Washington State Legislature adopted several of the key recommendations from the drought plan into State law.

This new two-stage drought system allows Washington State to issue a drought advisory when water supply conditions are below normal but not yet at a level where hardship is anticipated.

The Washita Reservoir Operations Pilot Study (2018) demonstrates how climate projections and paleohydrology can support more flexible reservoir operations for drought management. In the Washita pilot study, Reclamation developed reservoir inflow reconstructions going back 600 years to capture past wet and dry cycles for Foss and Fort Cobb Reservoirs in Oklahoma. The analysis showed that the drought scenarios based on tree-ring reconstructions were more severe than scenarios based on the observed droughts over the 90-year period of record—meaning that the actual risks of drought were greater than previously understood.

Because the risk of dam failure often depends on the risk of flooding, appropriately characterizing the probabilities of extreme floods is crucial. Based on the results of a 2015 Reclamation Dam Safety Office pilot study for Friant Dam in California that explored the potential impacts of climate change, a supplementary climate change analysis is now included in the flood hazard section of dam safety review reports. This analysis includes a summary of the projected monthly and annual streamflow changes for each Reclamation facility, developed from historical and future streamflow projections based on downscaled climate change information. This screening level information, about when and where the largest and smallest median increases in average monthly streamflow are projected to occur, helps prioritize more detailed levels of analysis.

Over the past 20 years, the size and severity of wildland fires in the West have markedly increased. Post-fire debris flow and sedimentation from upstream fires can have adverse and costly impacts to Reclamation’s existing infrastructure and reservoir storage capacity. A recent USGS report projected that increases in the frequency and magnitude of wildfires will significantly increase rates of sedimentation in watersheds in the West within the next 33 years. In almost 9 out of 10 of the watersheds assessed by the USGS, sedimentation could increase by at least 10 percent. In some watersheds, erosion and sedimentation could increase by 1,000 percent (Sankey et al. 2017).

Reclamation is developing geographic information system (GIS)-based mapping tools to provide information in real-time about the proximity of fires to Reclamation infrastructure. A West-wide map was developed in the summer of 2020 to assess risk during an unprecedented season of wildfires in the West. In Reclamation’s Columbia-Pacific Northwest Region, more detailed mapping is underway that, once completed, will display near real-time national fire perimeters, satellite heat signatures, and detailed asset and lands information (mapped jurisdictional lands, restoration sites, bridges, etc.). This map will help staff quickly identify potential impacts to our infrastructure, including post-fire sediment influx. This effort will help coordinate with downstream agencies for large fires that could create substantial sediment influx outside of the burned footprint.