THIS STUDY ADDRESSES TWO QUESTIONS: 1) How much can dynamic & adaptive informal water tranfers affect overall water availability? 2) What are their limits in an increasingly stressed basin? Simple transfer mechanisms that operate within the current doctrine of prior appropriation can be used to ensure water deliveries for the users that engage in them. This study explores how such transfers affect water availability in the Upper Colorado River Basin within the state of Colorado, if applied to an increasingly larger scale. We explore this using an ensemble of scaling ‘rules’ that differ in when they are triggered, the number of rights they include and the degree of scaling they consider. Under an increasingly stressed future–where dry conditions are becoming longer and more frequent–we would like to understand the capacity of such adaptive behavior to modulate more extreme droughts. More specifically, we’d like to identify if and under what conditions adaptive water transfers become insufficient tools in ensuring both water availability for rights’ holders and deliveries downstream. Preliminary results show that while adaptively scaling of individual water demands generally increases water availability in the basin, the effectiveness of this mechanism varies as a result of its interactions with the hydrologic conditions it’s applied to. AUTHORS Antonia Hadjimichael1,2, Patrick M. Reed1, Chris R. Vernon3, Travis Thurber3 EXPLORING THE CONSISTENCY OF INFERRED WATER SHORTAGE VULNERABILITIES IN A MULTI-ACTOR, MULTI-SECTOR RIVER BASIN THROUGH THE USE OF DYNAMIC AND ADAPTIVE WATER RIGHT TRANSFERS RIGHTS’ HOLDERS IN WESTERN RIVER BASINS ARE ENGAGING IN FORMAL AND INFORMAL RIGHTS TRADING Such transfers modulate the effects of drought for downstream water users. Financial compensation from state agencies could also help augment the basin’s downstream deliveries. 1 School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA. Email: ah986@cornell.edu 2 Department of Geosciences, Penn State University, University Park, PA, 16802, USA 3 Pacific Northwest National Laboratory, Richland, WA, USA. This research was supported by the U.S. Department of Energy, Office of Science, as part of research in MultiSector Dynamics, Earth and Environmental System Modeling Program. MSD SCOPE AND INNOVATION OF EXPERIMENT 1 Create 600 exploratory adaptive demand scaling rules tailored to each user 2 3 4 Low Flow Trigger Reflects risk aversion to streamflow levels that have historically caused severe shortages Each rule is designed based on the values of three control variables: Percent of rights Scaling amount Percentage of rights in the basin that scaling is applied to Amount of scaling applied to each right Each rule affects each user differently depending on the seniority of their rights and the hydrologic conditions they are facing Test rules under increasingly stressed hydrologic conditions 1000 synthetic streamﬂows x 600 demand scaling rules = 600,000 model runs Perform computational experiment on high-performance computing resources Use 20,000 core hours to perform 600,000 model executions Looking at data for 350 users across all moder runs results in 259 billion records Compress outputs to much smaller storage volume using compressed .parquet file formatsing Manage and analyze dataset with SQL and DuckDB Use queries to process and store data in tabular formats (e.g., dataframes), while allowing for interactive analysis and visualization. INTEGRATED MULTISECTOR MULTISCALE MODELING Water user A Water user B Water demand at this location When scaling rules are applied they reduce water demand Effects on streamflow leaving the basin Streamﬂow under one hydrologic realization Effect of adaptive scaling rules on water availability Historical range of flows in the basin since 1908 Synthetically generated stochastic flows for the basin, assuming stationary conditions Synthetically generated stochastic flows for the basin, based on CMIP5