Happy Water Week!
Have you ever seen the Sierra Nevada of California from the San Joaquin Valley in early spring on a clear day? When the Sierra is covered in snow and the air quality allows us to see it from here, that view is unmatched.
Every year at this time, when I look at the Sierra from the Valley, I know that if I see little snow, it will be a dry year. When there is plenty of snow like now, I know there will be fewer water supply challenges during the summer, but there may be floods. Floods can be caused by rain on snow and by high spring temperatures that melt the snow faster and earlier than usual. Climate change is causing earlier and faster melting.
Last week’s snow level study confirmed what we see in the mountains. The California Department of Water Resources reported that the state’s snowpack measured 96% of average at its peak on April 1st. There are nuances, as the north received 120% and the south only 84%. We can say these are relatively good news, but we must also remember that the last three years of average snowpack were followed by a severe drought from 2020 to 2022, the driest three-year period on record in California.
These climate extremes and abrupt weather changes we experience here are becoming more frequent with climate change, which is why we need to plan for both floods and the next dry period that could be just around the corner.
In this Water Week 2025, we need to reflect on how to prepare for climate extremes by modernizing our water management. In previous years, rapid melting has caused floods and concerns about the structural integrity of some dams. For example, in 2017, nearly 200,000 residents had to be evacuated downstream of Oroville due to the likelihood of a collapse after a rain-on-snow event.
That’s why it’s vital that the state is working with the scientific community on a new management strategy to reduce flood risks for downstream communities and benefit water supplies during dry periods. This strategy is called FIRO, which stands for “Forecast-Informed Reservoir Operations,” and it’s a new approach that can help us manage water extremes more flexibly.
Numerous dams in California are designed with a dual purpose: to have the capacity to capture floodwaters and prevent floods, while simultaneously serving as reservoirs for water storage. Traditionally, without FIRO, these dams are operated following rigid rules based on the calendar, which determine the volume of water that must be maintained in the reservoir according to the time of year.
What FIRO brings is allowing dam operators to use weather forecasts to make smarter decisions about water levels. They can release water preventively before significant storms to create additional capacity, or conserve it when forecasts do not indicate imminent risks of precipitation. This flexible approach optimizes water management on both fronts: minimizing flood risks and maximizing resource availability.
In essence, FIRO enables operators to retain more water in reservoirs for future use. That is, FIRO eliminates the “fear of missing out” (FOMO) regarding water that could have been stored if better prediction tools were available.
FIRO: From California to the World
Once upon a time (and still persists) a megadrought in California that reached a critical point during the severe water scarcity period between 2012 and 2016. Water enthusiasts in California may know that this drought was the catalyst that drove the Sustainable Groundwater Management Act (SGMA), which in turn highlighted the need to strategically reuse nearly a million acres of irrigated agricultural land in the state. At that time, dam operators watched with concern as invaluable water was released from dams as a preventive measure against floods, even when there were no rain forecasts or accumulated snow to melt. This situation demanded a solution.
The pioneering FIRO project was implemented at Lake Mendocino in the Russian River basin in northern California. There, a multidisciplinary team of scientists, water managers, and engineers collaborated with the Army Corps of Engineers, the National Oceanic and Atmospheric Administration (NOAA), the Scripps Institution of Oceanography, and the California Department of Water Resources to develop an innovative solution. The decisive element was the advances in hydrometeorological forecasting, which allow for more accurate predictions of temperature, precipitation, and river flows. This scientific knowledge on climate, meteorology, and hydrology is continuously refined through the work of federal agencies such as NOAA and NASA, in close collaboration with the scientific community.
From this initial experience, similar methodologies to FIRO have emerged in various regions of the country. In Seattle, for example, a better balance between flood protection and water availability is expected to be achieved by implementing FIRO at the Howard Hanson Dam in the Green River basin. In the Midwest region, Lake Erie has LEOFS (Lake Erie Operational Forecast System) to efficiently manage water levels affected by seasonal variations and climate change. The Tennessee Valley Authority has also adopted this flood management approach to address extreme precipitation events, particularly in the face of the increasing frequency of hurricanes and other extreme weather phenomena affecting the southern United States.
This revolution in water management transcends borders. Outside the United States, countries like Australia and Japan, as well as the Mediterranean region, are progressively incorporating meteorological forecasts into the planning and operation of their reservoir systems.
Transformative Benefits of Implementing FIRO
The power of FIRO lies in its ability to revolutionize multiple aspects of water management. Firstly, it optimizes water availability precisely when communities, the agricultural sector, and ecosystems need it most. By retaining water in reservoirs until meteorological forecasts indicate a genuine need for flood prevention, vital water reserves are ensured for our characteristic Mediterranean summers.
This system represents a qualitative leap in flood management compared to traditional methods based on predetermined calendars. With FIRO, water release decisions are based on the convergence of meteorological forecasts and hydrological models (hydro-meteorological science) that identify real flood risks, surpassing reliance on mere historical statistics.
A significant advantage of the FIRO system is its ability to increase water storage without requiring additional construction. In a context where new dam projects face increasing environmental, social, and economic obstacles, FIRO allows for maximum use of existing infrastructure through smarter operation. Additionally, the precision provided by hydrometeorological forecasts facilitates the scheduling of strategic environmental releases, ensuring that the ecological needs of rivers and aquatic species are addressed at precise times.
Lastly, FIRO is a fundamental tool for strengthening resilience against droughts, an increasingly pressing concern as climate change intensifies dry periods in numerous regions. By conserving water during risk-free intervals within the wet season, both communities and farmers can secure strategic water reserves to cope with drought episodes that would otherwise quickly deplete available resources and impose severe consumption restrictions.
Challenges on the Horizon of Implementation
Despite its obvious benefits, the implementation of FIRO presents various challenges that require consideration. While the reliability of meteorological forecasts is notably high, especially on the West Coast of the United States, not all regions of the country or the world have this level of precision. There is always a degree of inherent uncertainty in any prediction. Although the accuracy of forecasts improves annually, dam operators must consider this small but existing margin of uncertainty when making decisions about flood risk management.
To address this uncertainty, the use of probabilistic forecasts and ensemble systems is essential. In situations where prudence dictates releasing volumes of water greater than optimal for flood protection, there is the possibility of mitigating this impact by channeling these surpluses into aquifer recharge projects. These recharge systems not only provide additional underground storage but also contribute to counteracting land subsidence issues, protecting our aquifers to prevent our domestic wells from running dry, preserving ecosystems dependent on groundwater, and preventing saline intrusion in coastal areas.
FIRO also faces significant technical and institutional barriers. From a technical perspective, it requires specialized knowledge in meteorology, hydrology, and reservoir management—skills that are not always available in water management agencies. On an institutional level, it entails a cultural transformation that moves away from operations based on predetermined calendars to adopting a dynamic decision-making model based on forecasts, which can generate resistance in organizations accustomed to conventional methodologies. While these transformative transitions take time, it is encouraging that both the Army Corps of Engineers and the Bureau of Reclamation are actively supporting FIRO initiatives.
The marked climatic, topographic, and reservoir characteristic differences between different regions make it impossible to simply replicate the FIRO model from one basin to another. Each implementation requires specific adaptations based on local conditions. This diversity underscores the importance of integrating local communities into decision-making processes, as they often possess invaluable knowledge about basin dynamics and have legitimate interests in reservoir management that must be considered to ensure successful implementation.
The Future Belongs to FIRO
Advances in climate science and supercomputing will continue to refine meteorological forecasts. Artificial intelligence (AI) is enhancing this approach, increasing the effectiveness of FIRO. The integration of AI into meteorological models promises unprecedented accuracy, enabling more informed decisions about water storage and release. In the near future, high-precision weather forecasts could extend from days to weeks, giving reservoir operators a broader time frame to prepare for extreme events.
As climate change intensifies both extreme floods and droughts, FIRO and similar methodologies become essential for modern water management, as recognized by recent legislation in California through the Atmospheric Rivers Forecasting and Forecast-Informed Reservoir Operations and Hazard Resilience Research Program (AR/FIRO). The AB30 law (2023) updated the regulatory framework to explicitly incorporate FIRO as a strategic tool in managing water scarcity and preventing floods.
However, the true revolution that FIRO represents goes beyond the technological realm; it is a new conception of infrastructure. Instead of just building larger dams or higher levees, FIRO shows that, sometimes, the most effective solutions arise from the intelligent optimization of existing resources. This paradigm reflects the adaptive thinking necessary in the face of a changing climate, reminiscent of our initiatives to convert agricultural lands to more sustainable multiple uses.
FIRO provides the essential flexibility that water operations require to adapt to climate change and its multiple consequences: early melting, more frequent extreme events, warming of river waters, increased evaporation in lakes, marine intrusion, land subsidence, and overexploitation of aquifers. In the uncertain climate landscape we face, approaches like FIRO—that embrace uncertainty through scientific advances—will be crucial for the sustainability of communities, economies, and ecosystems. Although the water and environmental challenges that lie ahead are formidable, I remain optimistic: if we trust in science and listen to the voices of citizens, we can build a water future characterized by resilience and sustainability.
