Overview 

The overall goal of this tutorial is to demonstrate how to integrate ensemble forecast data into an HEC-RTS workflow to support the evaluation of Forecast-Informed Reservoir Operations (FIRO). The tutorial focuses on linking an HEC-RTS model with an HEC-ResSim model configured for standalone operation, enabling the use of ensemble forecasts within reservoir simulation and decision-support workflows.

FIRO is recognized as a risk-informed operational approach that integrates meteorological and hydrologic forecasts, including probabilistic and ensemble streamflow information, to support real-time reservoir release and storage decisions while complementing traditional rule curves.  An ensemble streamflow forecast is a collection of streamflow predictions that represent a range of possible future hydrologic conditions derived from multiple meteorological forecasts, hydrologic model states, parameters, and initial conditions. By using ensemble forecasts, decision-makers can explicitly represent uncertainty in hydrologic predictions and evaluate a range of potential operational outcomes.

Upon completion of this tutorial, you will be able to:

  1. Acquire meteorological gridded data from the National Blend of Models (NBM) and ensemble forecast streamflow data from the National Weather Service River Forecast Center in your region.
  2. Set up the watershed to forecast rainfall–runoff responses and reservoir operations under two configurations:
    1. Baseline setup: Use HEC-RTS with deterministic meteorological inputs to drive the HEC-HMS and HEC-ResSim models.
    2. Ensemble setup: Use ensemble forecast streamflow inputs to drive the HEC-ResSim model only.
  3. Review and compare results from the two model configurations for supporting FIRO.

Tutorial Data

Download and unzip this file within the C:\ directory on your computer. After unzipping the project, you should see a C:/CWMS_EFP directory with subfolders named "database," "forecast," and "watershed." 

CWMS 3.5.0 was used to create this tutorial.

Solutions_model_integrating_ResSim_Ensembles.zip

Tasks 

The four main tasks for this tutorial are:

  1. Acquire model input data
  2. Configure the baseline HEC-RTS setup
  3. Configure the ensemble HEC-RTS setup for HEC-ResSim only run
  4. Review and compare results from the two model configurations for supporting FIRO

It is noted that Tasks 1 and 2 were completed in a previous tutorial and are summarized here for continuity. Refer to Tutorial: Incorporating Ensemble Forecasts into HEC-RTS Watersheds for detailed instructions. However, briefly describe each task to maintain a complete and traceable workflow.