Introduction

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Water for the Seasons was a four-year research project funded by the National Science Foundation (NSF) and the United States Department of Agriculture (USDA) with the purpose of examining and connecting hydroclimatic, surface, and groundwater models with decision-making on snow-fed, arid-land river systems under different climate scenarios. The project focused on improving decision-making when faced with extreme drought and flood scenarios. The project team consisted of physical and social scientists, specifically engineers, hydrologists, hydrogeologists, extension educators, policy analysts, and economists, partnered with stakeholders representing interests from the headwaters to the terminus. The goal of this approach was to co-develop scenarios and resources to inform water management decisions across the river system based on stakeholder-driven climate model inputs.

The Truckee-Carson River System, consisting of two connected rivers systems, was chosen as the pilot system. The Truckee River basin is comprised of 3,060 square miles (1,958,400 acres) across California and Nevada and is fed by water stored in winter snowpack that flows as spring and summer snowmelt. The Truckee River begins its route in the eastern Sierra Nevada range, traveling approximately 120 miles to Pyramid Lake, a desert terminus lake located on the Pyramid Lake Paiute Reservation in Nevada. A portion of the Truckee River is diverted at Derby Dam into the Truckee Canal to store water in Lahontan Reservoir for use by the Truckee-Carson Irrigation District. The watershed provided an exceptional study site due to its small geographic area while being subject to many of the water management challenges of the American West. The Water for the Seasons project selected the Truckee-Carson River System as a pilot system to design a comprehensive suite of climate models that integrated climate science with human decision-making.

Key Issues Addressed

In 2015, the Truckee-Carson River System experienced an exceptionally severe drought year following three earlier drought years. During this winter, the Sierra-Nevada experienced almost no major atmospheric river storms that can build an exceptional snowpack needed to replenish the arid-land river system. This snowpack supports the cities of Reno and Carson City, irrigates agricultural fields, nourishes culturally-significant fish species, provides spawning habitat for diverse aquatic wildlife, and sustains wetlands for migratory birds. This region of the Great Basin typically receives little summer precipitation and is almost entirely dependent on spring and summer snowmelt.

Seasonal forecasts are challenging to develop for this region due to variability in precipitation and reliance on snowpack. Weather forecast skill is high 7-10 days out, but long-term climate and three-month seasonal forecasts are less reliable. This makes it difficult for stakeholders to plan effectively and manage resources for the water year. Using climate scenarios that span potential water year conditions helps prepare stakeholders for extreme events earlier to provide more time for collaborative decision-making. Apart from water accessibility, water rights further complicate allocations among water users and managers. The seniority of Prior Appropriations water rights held by urban, agricultural, and Tribal water users determines the order in which users receive annual water allocations. Farmers in the area typically have senior water rights that grant them seasonal water from April through October. However, there must be water in the river system at that time for them to receive allocations, and changes in climate have been affecting the form and timing of winter precipitation. More rain and less snow in winter increases off-season river flows and decreases snowpack runoff flows during the agricultural season. Winter river flows are typically used to replenish the wetlands at the end of the Truckee-Carson River System, making it difficult for local farmers to capture off-season water and establishing a dependence on annual allocations. 

Project Goals

• Develop a model to simulate an entire river system based on climate scenarios defined by stakeholder knowledge and water law:
  • Link multiple hydrologic and river operation models together to facilitate system-wide supply and demand projections
  • Analyze model simulations to create collective decision options for stakeholders
• Facilitate extensive stakeholder engagement through iterative interactions between water managers and researchers:
  • Regularly communicate with water managers during the entire project
• Create a collaborative modeling framework to investigate and improve water sustainability, climate resiliency, and encourage stakeholders to engage in collaborative decision-making forums

Project Highlights

Working Together: Engaging stakeholders from the beginning of the project to writing the final report, helped the project team find informative and useful results designed specifically for water managers and users. 

• Research Design: The team first conducted in-depth research into the history of conflict management around water in the Truckee-Carson River System. This practice allowed them to better identify and work with local stakeholders. The research design involved the following steps:

1. Conduct a comprehensive literature review and review archival documentation on the system to understand long-term issues of concern and litigation involving water allocation
2. Model water supply and demand in the Truckee-Carson River System including all legal and policy constraints under different climate scenarios
3. Develop and implement surveys with local water managers and users about the impacts of droughts and potential strategies for adapting to increasingly variable water supplies
4. Integrate key water management organizations representing diverse water uses into the research process
5. Compare climate change climate change
   Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.
   
   Learn more about climate change impacts in the pilot system with other snow-fed arid land systems around the world

• Co-Production Science Approach: Stakeholders were engaged and included throughout the entirety of the project to conduct research that incorporated their knowledge. This included creating a Stakeholder Affiliate Group (SAG) composed of twelve representatives from communities reliant on the system. The team met through workshops over all four years of the project.
• Community Evaluations: Evaluations were completed after each stakeholder meeting to ensure the involved members’ needs, wants, and interests were continuously understood and met. Other community members also provided direct feedback as results of the project were shared with local jurisdictions, environmental groups, Tribal resource managers, and the scientific community.
• Collaborative Modeling: The project integrated a suite of models including climate data as well as data collected from local stakeholders to inform decision-making. Data included:

1. Surface and groundwater flows and levels
2. Evapotranspiration rates and natural and built reservoir evaporation rates
3. Climate variables including daily and annual projected temperature and precipitation
4. Reservoir storage and water release options for both flood management and water use
5. Water-use priorities under different climate scenarios including droughts, floods, and changes in precipitation variability and timing
6. Legal and political arrangements in the water system
7. Stakeholder engagement and priorities
8. Strategic responses to different hydroclimatic scenarios 

Lessons Learned

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The outcomes of the Water for the Seasons collaborative-research approach highlight the benefits for a project to seek and interactively respond to community feedback as an integral part of co-developing scientific models. Through this study, extension outreach fact sheets, reports, and training materials for water users and managers were developed, collaborative stakeholder understanding of future water supply and use increased, and trust was built between researchers and stakeholders by establishing a collaborative environment to generate more innovative responses and reduce future conflict. This participatory framework helped to collectively improve climate resiliency for water users and managers and improve understanding among researchers and stakeholder groups about the challenges of managing scarce water resources in a changing climate. The relationships and trust built to make collaborative decisions moving forward is the most tangible outcome of this project. 

Researchers suspect that this type of modeling would work best in areas with similar climatology and water legal arrangements like the semi-arid American West and in semi-arid lands elsewhere. The same collaborative modeling approach could also be applied in tropical rain-fed systems. Collaborative stakeholder involvement is a key piece to understanding water sustainability in many other regions looking to improve climate resilience and equity among diverse stakeholder communities. Many of the fundamental principles and best practices of the Water for the Seasons project may be transferred, scaled, or applied to river systems around the world.

Incorporating water managers and users from the beginning of the project produces the most effective and useful information. Without the inclusion and creation of a stakeholder working group, scientific models and analyses do not include stakeholder equities or provide answers to questions that directly inform decision-making and therefore strengthen resiliency.

One component of the research was to ask stakeholders to define tipping points of a community resilient to extreme climate events. At the outset, Water for the Seasons proposed that a climate-resilient community is one that is prepared for extreme climate events based on coordinated adaptation and response. This requires that diverse community members communicate and respond collectively to overcome extreme climate events. As the project progressed, it became apparent that the term resiliency had different temporal, geographic, and economic implications to different stakeholder groups. Without a framework for diverse stakeholder communities to share perspectives, equities, and cultural values and to adjust their decision-making accordingly, achieving system resiliency becomes more challenging.

Next Steps

• Incorporate into local and regional drought contingency and climate adaptation plans throughout the study area using knowledge gained from this research
• Address specific stakeholder considerations such as strategies for the implementation of alternate or cover cropping, the management of aquifer storage, and the use of water banking and trading arrangements in future iterations of this research
• Adopt the suite of hydroclimatic models to assess water sustainability and climate resiliency among diverse stakeholder groups in other locations
• Educate and improve climate knowledge as patterns in climate variability shift 

Funding Partners

• National Science Foundation
• United States Department of Agriculture, National Institute of Food & Agriculture

Resources

• Water for the Seasons Project Overview 
• Collaborative Modeling to Assess and Enhance Community Climate Resiliency
• Assessing the Climate Resiliency and Adaptive Capacity of the Truckee-Carson River System
• Collaboratively Modeling Water Resources in the Truckee-Carson River System
• Climate Scenarios for the Truckee-Carson River System 

CART Lead Author

• Emily Bickle, Research Assistant, Drought Learning Network

The DLN is a peer-to-peer knowledge exchange between climate service providers and resource managers, created to gather and share lessons learned from drought events to prepare for future events. The DLN partners with CART to develop Case Studies, with funding from the National Drought Mitigation Center for interns and coordination support from the USDA Southwest Climate Hub.

Suggested Citation

Bickle, E., R. (2020). “Decision-Making in Snow-Fed, Arid-Land River Systems.” CART. Retrieved from https://www.fws.gov/project/snow-fed-arid-land-river-systems.