Dam Removal and River Restoration in Watershed Planning

Transcription

1 LOCAL WATER, GLOBAL WATER. ESP, DENISON UNIV Dam Removal and River Restoration in Watershed Planning Tim Granata Ecological Engineer Department of Civil & Environmental Engineering & Geodetic Science Ohio State University Data published in: Zika and Granata. 2007, In: Economic Valuation of River Systems. Ed. F. Hitzhusen, Krause et al. 2007, In: Economic Valuation of River Systems. Ed. F. Hitzhusen

2 Some fact about dams Two types: High Head > 5m & Low head < 5m Low Head s are vast majority in USA Over 75% of dams more than 50 years old Due for permitting renewal, may not pass Ohio has 9000 known dams (ODNR register) In Ohio dams used for: Water Supply Reservoirs Flood Control Electric Power Generation Mill Power & Canal System (Historically)

3 Dams modify river systems to lake systems creating longer Hydraulic Retention Times, HRT=V/Q

4 Consider two dams on the Sandusky River Ballville Dam Fremont, Ohio High Head Steep Sloped Channel Small Reservoir = 3 miles of backwater Large Upstream Habitat Small Downstream Habitat St. John s Dam Tiffin, Ohio Low Head Shallow Sloped Channel Large Reservoir = 14 miles of backwater Large Upstream & Downstream Habitats

5 Sandusky River Watershed Sandusky Co. Lake Erie Sandusky Bay Fremont Seneca Co. St. John s Dam Wyandot Co. Upper Sandusky Tiffin Loss of Habitat Bucyrus Ballville Dam Inaccessible Habitat Crawford Co. 10 miles 25 km

6 Ballville Dam, Sandusky Co. Sandusky River 120 m 10 m

7 Sandusky Co. Sandusky Bay Fremont Sandusky River Fremont, Ohio Seneca Co. Tiffin Ballville Dam Potential Habitat Levies Water Treatment Plant Wyndot Co. Crawfort Co. Remaining Walleye Spawning Area Flow 0 Ballville Reservoir Flow Ballville Dam 432 ft End of Reservoir (3 miles in Length) Approximate Distance in Feet (Aerial Photography) The Ballville Dam is located 18 miles upstream of Sandusky Bay. The dam impounds 89 acres of water and serves as the only water supply for the City of Fremont (population 32,645). The dam was constructed in The concrete structure is 432 feet wide and 34 feet high. Sandusky River with dam and habitat locations (provided by Scudder Mackey, Ohio Dept. Natural Resources-ODNR GS).

8 River Mile 36 N Potential Habitat Upstream of Ballville Dam Riverine Substrate Mapping River Mile 35 Silt/Clay Sand Gravel/Pebble Boulder/Cobble Limestone Bedrock

9 St. John s Dam, Seneca Co., Sandusky River 20 m 2 m

10 Bay St. John s Dam, Seneca Co. Sandusky Co. Fremont Seneca Co. Tiffin St. John s Dam Wyandot Co. Crawford Co. High Quality Habitat (Courtesy of ODNR GS) Reservoir

11 Pro s Water Supply Flood (Discharge) Control Recreation (motor boating) Dammed Rivers Con s Loss of Connectivity Sedimentation Loss of Riparian Habitat Poorer Water Quality Safety Hazard Boating & Personal Higher Water Levels Pro s Restored Rivers Con s Connectivity (migration) Loss of Power Boating Channel Stability & Loss of Water Supply (?) No Net Sedimentation Sediment Release (?) Habitat Gain Experience & Expertise (?) Better Water Quality Small Boating & Fishing Reduced Water Level (Flood Control)

12 Fate of our two Dams St. Johns Dam, Tiffin, OH water company own dam breach east crest no sediment accumulated ODNR Scenic Rivers financing removal Reservoir being drained via larger breach this Spring, 2003 Complete removal Summer 2003 Ballville Dam, Fremont, OH City owns the dam crack in west spillway 8 m of sediment accumulated 2003 dam safety inspection poor water quality for city water Migratory spawning curtailed City to build off-line reservoir ODNR (Div. Wildlife) pushing removal What will Fremont do? What would you recommend?

13 Coho Dam, Huron River Removal June 2002 Dam Removal and River Restoration are Important Tools in Watershed Planning After Removal August 2002