1. US Army Corps of Engineers BUILDING STRONG ® Reservoir Simulation Software “Westfield Sub-basin” Presenter – John Hickey, HEC August 2010

2. BUILDING STRONG ® HEC-ResSim Simulate the influence of reservoirs and diversions on flows in a river system. Decisions about reservoir releases are made in accordance with user- defined rules.

3. BUILDING STRONG ® Connecticut River Basin  44 Sub-basins  60+ Large Reservoirs  143 Ecological points of interest  320+ SYE inflow hydrographs  362 River Reaches

4. BUILDING STRONG ® Westfield Subbasin - Case Study Multi-purpose operations (flood management, hydropower, water supply) Varied ecological concerns (floodplains, salmon stocking, diadromous fish) Also… Availability of hydrologic data One of first subbasins to have working simulation and optimization models

5. BUILDING STRONG ® Reservoirs on the Westfield The Westfield consists of three major dams essentially running in parallel.  Knightville  Littleville  Cobble Mountain/Borden Brook Flood management, hydropower, and water supply objectives are prevalent within the sub basin  Knightville – Flood Management  Littleville – Flood Management  Cobble Mountain/Borden Brook – Hydropower and water supply

6. BUILDING STRONG ® Physical Information for Model Physical Components:  Reservoir Pool  Dam (and its Outlets)  Diverted Outlets Hierarchical Outlet Structure Multiple outlet types Diverted Outlets Hydropower Outlets  Capacity  Efficiency

7. BUILDING STRONG ® Operational Rule Blocks Priority based Rules at the Dam Rules for downstream locations Rules on individual outlets Rules for other locations Various types of rules  Min/Max release  Rate of Change  Downstream Control  Hydropower  Scripting

8. BUILDING STRONG ® At Site Operations Knightville Dam: max flood release of 4,500-cfs. Littleville Dam: max flood release of 1,500-cfs. Borden Brook Mountain Dam: max flood release of 1,675-cfs. Cobble Mountain Dam: max flood release of 1,675-cfs. Knightville and Littleville Dam have minimum flows that are a function of season and reservoir inflow.

9. BUILDING STRONG ® System Operations within Tributary When two or more reservoirs operate for one site, ResSim uses a “system” operation that balances storage in the pools. Knightville and Littleville operate to control flows at Westfield to not exceed 11,250 cfs. Westfield

10. BUILDING STRONG ® System Operations for Mainstem Hartford Knightville and Littleville operate to reduce outflows if Hartford experiences high stages.

11. BUILDING STRONG ® Model Output

12. BUILDING STRONG ® Purpose  ResSim will be used to regulate and route hydrographs downstream.  Various reservoir management scenarios can be developed by changing rule sets for the involved project(s).  Regulated hydrographs for each scenario will be used to assess flow conditions at points of interest.