Event Title

Session D1 - Susquehanna River Two-Dimensional Hydraulic and Habitat Modeling

Location

UMass Amherst

Event Website

http://fishpassage.ecs.umass.edu/Conference2012/

Start Date

5-6-2012 10:30 AM

End Date

5-6-2012 10:50 AM

Description

As part of the Conowingo Hydroelectric Projects FERC relicensing process, Gomez and Sullivan was asked by Exelon to build a two-dimensional habitat and hydraulic model of the Susquehanna River below Conowingo Dam. Conowingo Dam, located on the main stem of the Susquehanna River in Maryland, is the largest and most downstream of several hydroelectric dams in the lower Susquehanna River before the river flows into Chesapeake Bay. The 4.5 mile study reach extended from the downstream face of Conowingo Dam to the rivers confluence with tidal waters. The model's primary objective was to assess aquatic habitat for Conowingos normal operating flow range (3,500 cfs to 86,000 cfs).

The model, built using River2D software, required the compilation and input of several datasets, including combining recent topographic and bathymetric data, sediment survey results and stakeholder-approved habitat suitability index (HSI) criteria. Target species included several life stages for American shad, striped bass, smallmouth bass, shortnose sturgeon, macroinvertebrates (mayfly, stonefly, caddisfly) and several other aquatic species. Several other datasets, including RTK-GPS-derived water surface elevations and ADCP-measured water velocities, were used to calibrate the model to within ±0.15 ft of the observed water surface elevations.

After the model was calibrated, aquatic habitat was modeled for 23 distinct species, life stages and habitat guilds over the entire study area. Modeled bed shear stresses were used for a separate mussel habitat analysis, based on modeled shear stresses. The model results were compiled to create flow versus habitat relationships, persistent habitat maps, and a habitat time series analysis. The model also provided results for several other relicensing studies that required hydraulic data in the river, including a fish passage barrier analysis and a sediment entrainment analysis. The model results will be used to better inform Exelon, resource agencies and other stakeholders future flow management decisions for the Conowingo Hydroelectric Project.

Comments

Gary Lemay has a B.S in Civil Engineering and M.S. in Civil Engineering with a water resources focus, both from UNH. As a graduate student, his thesis assessed stream temperature impacts of culverts and impervious areas on coastal NH streams. Since he started at Gomez and Sullivan two years ago, Gary has been involved with various engineering and environmental studies, including IFIM studies, hydraulic modeling and reservoir sedimentation analyses.

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Jun 5th, 10:30 AM Jun 5th, 10:50 AM

Session D1 - Susquehanna River Two-Dimensional Hydraulic and Habitat Modeling

UMass Amherst

As part of the Conowingo Hydroelectric Projects FERC relicensing process, Gomez and Sullivan was asked by Exelon to build a two-dimensional habitat and hydraulic model of the Susquehanna River below Conowingo Dam. Conowingo Dam, located on the main stem of the Susquehanna River in Maryland, is the largest and most downstream of several hydroelectric dams in the lower Susquehanna River before the river flows into Chesapeake Bay. The 4.5 mile study reach extended from the downstream face of Conowingo Dam to the rivers confluence with tidal waters. The model's primary objective was to assess aquatic habitat for Conowingos normal operating flow range (3,500 cfs to 86,000 cfs).

The model, built using River2D software, required the compilation and input of several datasets, including combining recent topographic and bathymetric data, sediment survey results and stakeholder-approved habitat suitability index (HSI) criteria. Target species included several life stages for American shad, striped bass, smallmouth bass, shortnose sturgeon, macroinvertebrates (mayfly, stonefly, caddisfly) and several other aquatic species. Several other datasets, including RTK-GPS-derived water surface elevations and ADCP-measured water velocities, were used to calibrate the model to within ±0.15 ft of the observed water surface elevations.

After the model was calibrated, aquatic habitat was modeled for 23 distinct species, life stages and habitat guilds over the entire study area. Modeled bed shear stresses were used for a separate mussel habitat analysis, based on modeled shear stresses. The model results were compiled to create flow versus habitat relationships, persistent habitat maps, and a habitat time series analysis. The model also provided results for several other relicensing studies that required hydraulic data in the river, including a fish passage barrier analysis and a sediment entrainment analysis. The model results will be used to better inform Exelon, resource agencies and other stakeholders future flow management decisions for the Conowingo Hydroelectric Project.

http://scholarworks.umass.edu/fishpassage_conference/2012/June5/7