Seasonal to Inter-Annual Streamflow Simulation and Forecasting on the Upper Colorado River Basin and Implications for Water Resources Management

Cameron Bracken

The past decade has been one of unprecedented drought in the Upper Colorado River Basin (UCRB), having wide impacts on basin hydrology and management. The drought has raised many questions about the sustainability of the UCRB water supply and emphasized the need for accurate forecasts and simulations of streamflow.  The UCRB is home to many of the largest reservoirs in the United States including Lake Powell.  For large reservoirs such as these, the ability to forecast on a seasonal to inter-annual time scale is particularly important for management.  

In this talk I will take you through the lifetime of two statistical forecast models for UCRB streamflow. The first is a regession-type model for seasonal flow.  The second is a Hidden Markov time series model for inter-annual forecasting (though it originally developed as a simulation tool).  I will discuss the subsequent marriage of these models and their transformation into input to a decision support model. The final resting place of these forecasts is as input to the Midterm Operations Model, a new model for reservoir operations in the UCRB.