Viewing Results for an Ensemble Analysis

A variety of Graphical and Tabular results are available after an Ensemble Analysis is computed. All results from an Ensemble Analysis are accessed via the Results tab of the Watershed Explorer. The same results are also available for the current analysis, so long as no data used in the analysis has changed. The program tracks all of the data in the Ensemble Analysis including its ensemble members (Simulation Runs or Forecast Alternatives) and each of their Basin Models and Meteorologic Models. If any of the data has changed, you will need to recompute the Ensemble Analysis to update and refresh the results.

Once a result is open for viewing it will remain open until it is closed by the user. It is possible that data or model information used by the analysis that produced the result could change while the result is open for viewing. In this case, the open result will immediately show an indication that data has changed and the Ensemble Analysis needs to be recomputed. After the Ensemble Analysis is recomputed the open results are automatically updated with the new results and the indication is updated with the data and time of the most recent compute.

Ensemble Analysis Results

The results available for a computed Ensemble Analysis are based on the user's selections from the output control dialog accessed via the Compute tab of the Watershed Explorer as seen below. The time-series output types that are currently compatible within an Ensemble Analysis in HEC-HMS include outflow, reservoir elevation, incremental precipitation, LWASS, SWE, cumulative outflow, cumulative precipitation, moisture deficit, air temperature, sediment load, sediment volume, and bulk flow.

Graphical Results

Below is an example of an Outflow plot from a junction element present in each of the ensemble member base models. The traces of the ensemble member outflow results are shown in colored lines for reference. The dashed black lines are aggregated results computed from the ensemble analysis. The aggregated results include outflow mean, mean plus one standard deviation, mean minus one standard deviation, maximum, and minimum.

Tabular Results

Tabular results from an ensemble analysis are also included and will depend on the time-series selected by the user in the output control dialog prior to compute. Below is an example of a Maximum Outflow table from a junction element present in each of the ensemble member base models. The maximum outflows from each of the ensemble member base models are shown for quick comparison. In this example, most of the ensemble members show a similar computed maximum outflow value. The exception is ensemble member 4 which shows a much higher maximum outflow value.