Operations yield modelling in the Upper Colorado river basin

CSU has engaged SEI in exploring the impacts of long-term climate change on its water supply sources, while considering the limitations of its existing water rights. This scope of work includes both near-term forecasting and longer-term climate projections of CSU’s high-mountain water collection system in the Blue River. Some of this infrastructure – reservoirs and diversions in the form of canals and ditches – has a junior water right compared to other water users (including towns, farms and in-stream environmental flows) further downstream.

Separately, SEI uses the same WEAP-based model to explore summertime forecasting of their available and legally usable water supply. In both cases, climate datasets were automatically incorporated into the WEAP model, which simulated the hydrology, water rights and water supply.

Summer-ahead forecasting is performed using gridded seven-month-ahead seasonal climate forecasts. Seasonal forecasts are automated to run every month, with key results provided in an automatically updated webpage. CSU uses these forecasts and their own legacy spreadsheet-based methods to anticipate the water available for their customers in the summer ahead. They are also considering whether this product, based on climate forecasts, are more reliable than their existing methods.

Long-term water supply projections are performed using down-scaled climate data from selected Coupled Model Intercomparison Project Phase 5 (CMIP5) gridded climate change ensembles. CSU uses these to inform their Integrated Riverbasin Water Planning (IRWP) process and for drought planning.