This document summarizes the implementation of a Real Time Simulation (RTS) model using HEC software for a large hydroelectric power project. Key aspects include: 1) The RTS model integrates HEC-HMS, HEC-ResSim, and HEC-RAS models to simulate rainfall-runoff, reservoir operations, and river stages in real-time using meteorological forecasts. 2) The project area includes a 1,640 square mile watershed with 9 power houses, 6 reservoirs, tunnels, and open channels modeled. 3) The RTS model runs automatically every 6 hours using 2 weeks of observed data and 1 week of forecasts to generate custom reports for reservoir operations decisions.

1. Real Time Simulation Model (HEC‐RTS)
Sam Crampton, P.E., CFM

2. Real Time Simulation
• Publicly available* software
from HEC
• PC version of Corps
Water Management System
(CWMS)
• Recently implemented by
Dewberry for a major hydro
power project
• First private implementation of
HEC‐RTS
* Not fully released at this time

3. Why RTS?
• Has an interface to receive and process real‐time and forecast
meteorological data for real time hydrologic and hydraulic
simulations
• Provides a system to integrate different models including:
– HEC‐HMS, rainfall‐runoff model to develop hydrographs
– HEC‐ResSim, reservoir operation model (spillway releases, pumped
storage, power generation, operating rules etc)
– HEC‐RAS, hydraulics model to predict river stages
– HEC‐FIA, flood impact analysis (not implemented in this project)

4. Implementing for Large Scale Hydro Power
• Project area:
– 1,640 square mile
watershed
– 9 power houses
– 6 major reservoirs
– 54 miles of diversion
tunnels
– 160 miles of open
channel

5. HEC‐RTS Setup for Hydro Power project
• HEC‐RTS simulation runs every 6 hours automatically
– 2 weeks of “lookback” using observed data
– 1 week of “forecast” using weather forecast services
• Uses HEC‐HMS, HEC‐ResSim and HEC‐RAS models
– These models can be accessed through HEC‐RTS interface
• HEC‐HMS includes snowmelt modeling
• Scripts written that allow inclusion of diversions and outage
schedule without having to open the RTS model
• Custom reports are generated and sent to the Managers and
Operators as an email attachment for decision support.

6. HEC‐HMS
Model
ResSim
Model
HEC‐RAS
Model
RTS
Program
Edison
Mammoth
Pool
Redinger
Florence
Huntington
Shaver
METEOROLOGICAL
DATA INPUTS
(Updated hourly)
PLANT
OPERATORS

7. RAS
ResSim
HMS
Weather
Data
GageInterp
MFP
Inundation
Mapping
Model Sequence
Observed and Future
Precipitation,
Snowpack, and
Temperature
Custom Report
Generator
• Meteorological Forecast Processor
– Processing gridded precipitation
and temperature data for real time
and forecasted conditions
• HEC‐HMS – Development of real‐
time hydrographs using forecasted
and observed data
• HEC‐ResSim – Simulation of
reservoir operations using flows
delivered by HEC‐HMS
• HEC‐RAS – Simulation of river
stages, rate of rise in river and
duration
• RAS Mapper – Real time mapping of
inundation
• Custom Report Generator –Decision
support for reservoir operations
HEC‐RTS
Observed stream
flow information

8. Meteorological Forecast Processor

9. Snowmelt and Temperature Considerations

10. Snowmelt and Temperature Considerations

11. Temperature Grids
Gridded Temperature using Lapse Rate VS Temperature Averaged by Sub Catchment
Averaged Lapse RateWith Lapse Rate

12. Area
Weighting
Determine area‐weighted average
hyetographs for subbasin
MFP – Gridded Radar Precipitation and Forecast

13. Compare simulated hydrograph with observed hydrograph and
calibrate hydrologic model
Compare simulated hydrograph with observed hydrograph and
calibrate hydrologic model
MFP – Comparing and Calibrating HMS

14. HEC‐RTS and HEC‐HMS
• HEC‐HMS used to
determine rainfall
runoff and to route
runoff to reservoir
• HEC‐ResSim used to
model reservoir
operations

15. HEC‐RTS and HEC‐ResSim

16. Data Management
• Data management is very
important
• Input data have to be in a
correct format and in a
correct folder directory
• Time‐series and Grids have
to be in a DSS format
• DSS files for
– Temperature
– Precipitation
– Snowgrids

17. HEC‐RTS
• Data Acquisition
• Data Visualization
• Watershed Setup
• Model Interface

18. Watershed Setup
• Assign Program
Sequence
• Add Model Alternatives

19. Model Interface
1) Create Model Alternative 2) Create Forecast Alternative

20. Model Interface
Create and compute a Forecast Run
– 2 weeks of Look‐back and 1 week of forecast

21. HEC‐RTS Model Interface
• Can edit HMS, ResSim and RAS through RTS

22. HEC‐RTS Model Interface ‐ Results

23. Custom Report
Application build to extract the time‐
series data from the forecast.dss file and
create graphs and output tables.
– Precipitation graphs
– Average and Total Precipitation for the
sub‐watersheds
– Elevation and Storage graphs for the 6
reservoirs
– SWE accumulation
– Reservoir Local Inflow
– Total Reservoir Release
– Flow triggers (alert if the model
forecast flows exceed tolerances)
– Flow through tunnels
– Change in Reservoir Storage

24. Challenges
• Current version of RTS does not take forecast temperature
grids so a supplemental program added to transfer the
forecast temperature grids to the forecast.dss file
• Snowmelt modeling requires temperature and 5 snow‐
related grids (SWE, Cold Content, Liquid Water, ATI Melt
and Cold Content ATI)
• Application built to transfer the 5 snow‐related grids after
the end of each simulation
• Scripts written to update diversion and outage schedule
without opening the RTS model
• Application built to generate a custom report that is used
for decision support

25. Key Future Enhancement
• Implement the HEC‐
HMS Graphical
Calibration Tool (in
development)
– Will simplify and
infuse efficiencies
for real time
calibration
• Use GIS to determine
hill shade and break
out north and south
slopes to enhance
snow melt
considerations

26. Questions???