1. www.ma-rs.org 2007 Water Resources Report Rob Montgomery River Flow & Lake Levels TMDL Study Floodplain mapping revisions Dredging 101

2. www.ma-rs.org Rock River Flow July 2005 – July 2007

3. www.ma-rs.org Rock River Flow 1990 – 2007

4. www.ma-rs.org Lake Koshkonong Stage July 2005 – July 2007

5. www.ma-rs.org Lake Koshkonong Stage 1990 - 2007 100-yr 864

6. www.ma-rs.org Rock River TMDL Study TMDL = Total Maximum Daily Load Load allocations for sediment and phosphorus for impaired streams and waterbodies Analyzing target phosphorus loads –0.08 mg/L for wadeable streams –0.125 mg/L for non-wadeable Allocations to point and non-point sources

7. www.ma-rs.org Rock River TMDL Study DNR to submit TMDL to USEPA, funded by USEPA Technical analysis ongoing, technical advisory committee meeting upcoming Lake Koshkonong will benefit, but changes will be slow in coming

8. www.ma-rs.org Floodplain Mapping Revisions Generally based on new topography, but old hydraulic analysis Dane County, Rock County: new maps, 90 day appeal period over Jefferson County: Appeal period not yet announced

9. www.ma-rs.org Dredging 101 Dredging can increase water depths and supply fill Expensive Usually conducted in critical navigation areas only Substantial permit requirements

10. www.ma-rs.org Types of Dredging Mechanical (excavated) –Usually used for smaller areas –Slower production than hydraulic –Smaller disposal area Hydraulic (suction – pumping) –Most cost-effective, especially for large areas –Usually requires large disposal area

11. www.ma-rs.org Mechanical Dredging JF Brennan

12. www.ma-rs.org Hydraulic Dredging Dredge Dredge Disposal Area Dredge discharge pipeline Return Flow

13. www.ma-rs.org Hydraulic Dredge JF Brennan Company Cutterhead Pump Discharge pipeline

14. www.ma-rs.org Hydraulic Dredge Disposal Areas Often 1.5 x Dredge volume Sediment dewatering return flow Land acquisition State of North Carolina

15. www.ma-rs.org Final use of dredge spoil area Spoil properties important Open Space, Agricultural, Wildlife area Applied Marine Sciences

16. www.ma-rs.org In-Lake dredge spoil placement to create habitat Dredge spoil placed behind confinement berms Would involve substantial permitting process on Lake Koshkonong Corps of Engineers Project at Pointe Mouillee, MI Lake Erie

17. www.ma-rs.org Factors Affecting Hydraulic Dredging Project Costs Dredge spoil site acquisition, preparation Access and mobilization Dredge material properties Pumping system Restoration Permit Conditions Costs could range from $20/cy

18. www.ma-rs.org Hypothetical Hydraulic Dredging Project 1000 ft x 300 ft (~7 Ac) x 2 ft depth = 22,000 cy Disposal – 3 ft depth – 8 acres Dredge & place: 22,000cy x $20/cy = $440,000 Property acquisition: 8 acres x $20,000 = $160,000 Total: ~ $400,000 to $600,000 Actual project costs could vary WIDELY

19. www.ma-rs.org Implementing a Dredging Project on Lake Koshkonong PLANNING Prioritizing navigation improvement areas Identify habitat improvement opportunities Effects on wind driven waves and ice push Funding Permit strategy Planning level engineering, costing DESIGN Sediment characterization Permitting Acquisition of land and access Specialist contractor

20. www.ma-rs.org Questions Thank You