Upper Mississippi River Floodplain Restoration Priorities in Pools 1, 2, 3, Upper 4 and Lower Vermillion River

Transcription

1 Upper Mississippi River Floodplain Restoration Priorities in Pools 1, 2, 3, Upper 4 and Lower Vermillion River Minnesota Department of Natural Resources Interdivisional Meeting July 8, 2009 Lake City Area Office

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3 Upper Mississippi River NESP Ecosystem Goals 1. Manage for a more natural hydrologic regime (hydrology and hydraulics) 2. Manage for processes that shape a physically diverse and dynamic river-floodplain system (geomorphology) 3. Manage for processes that input, transport, assimilate and output materials within the UMR basin river-floodplains: e.g. water quality, sediments, and nutrients (biogeochemistry) 4. Manage for a diverse and dynamic pattern of habitats to support native biota (habitat) 5. Manage for viable populations of native species within diverse plant and animal communities (biota) 3

4 Floodplain Restoration Features Pool-wide Water Level Management Gorge Restoration Floodplain Island Construction Backwater Dredging Carp Behavior Modification

5 Pool-Wide Water Level Management Drawdowns in Pool 2, 3, 4 and Lower Vermillion River with Commercial Navigation

6 Pool 5 Weaver Bottoms /13/05 Emergent vegetation increased as a result of the drawdowns. 9/14/05 Submersed vegetation increased. Pool 5 drawdown response, Weaver Bottoms

7 Pool 2 Potential Aquatic Vegetation Beds 2 feet or less = Potential Emergent and Submersed Aquatic Vegetation 5 feet or less = Potential Submersed Aquatic Vegetation Greater than 5 feet or flowing channel

8 Pool 3 and Lower Vermillion River Potential Aquatic Vegetation Beds 2 feet or less = Potential Emergent and Submersed Aquatic Vegetation 5 feet or less = Potential Submersed Aquatic Vegetation

9 Upper Pool 4 Potential Aquatic Vegetation Beds 2 feet or less = Potential Emergent and Submersed Aquatic Vegetation 5 feet or less = Potential Submersed Aquatic Vegetation

10 Floodplain Islands in Pools 2, 3, and Upper 4 Reduce wind fetch which decreases suspended sediments and turbidity Channelize water flow Encourages and protect vegetation growth Reduce water column nutrient concentrations Provide fish and wildlife habitat October 1961 August 1994 August 2000

11 Lower Pool 2 Islands - Preliminary Design Plan PROBLEM IDENTIFICATION Major habitat concerns for Lower Pool 2 are high turbidity, sedimentation, sediment resuspension, island dissection, vegetation loss, and reduced depth for over-wintering fish. PROPOSED PROJECT The project involves constructing a series of 10 islands to reduce wind-generated wave erosion and sediment resuspension. The islands would better focus flow down existing channels. 11

12 UMR - Lower Pool 2 July 8, 2008 Water Level Elevation at Pool 2 Gage = (1912 NGVD) Discharge Q= 14,300 cfs 12

13 UMR - Lower Pool 2 1 Mile 2007 Bathymetry Legend Lower Pool 2 Bathymetry - Depth in Feet Value High : 0 Low : Mile Water Level Datum = feet (1912 NGVD) 13

14 UMR - Lower Pool 2 Preliminary Plan Legend Pool 2 Wind-Fetch Value High Low Corps run of USGS Wind-Fetch model 2009 Wind Fetch Existing Conditions 14

15 UMR - Lower Pool 2 Preliminary Plan I H G F E D K C B A J 2007 Bathymetry Legend 4 Lower Pool 2 Bathymetry - Depth in Feet Value High : 0 Low : Fines borrow area 1 Mile Water Level Datum = feet (1912 NGVD) 15

16 UMR - Lower Pool 2 Preliminary Plan Legend Pool 2 Wind-Fetch Value High Low Corps run of USGS Wind-Fetch model 2009 Wind Fetch with Islands 16

17 North and Sturgeon Lake Islands Preliminary Design Plan PROBLEM IDENTIFICATION Major habitat concerns for North and Sturgeon lakes are loss of bathymetric diversity, reduced seasonal aquatic refugia, island dissection, and loss of aquatic vegetation. PROPOSED PROJECT The project involves constructing a series of small islands (approximately seven within North Lake and five within Sturgeon Lake) using main channel sands to reduce wind and wave generated erosion. Island construction would utilize finegrained substrates found within North and Sturgeon Lakes to enhance bathymetric diversity and provide island topsoil. 17

18 UMR Pool 3 - Sturgeon Lake June 23, ,700 cfs 18

19 UMR Pool 3 - Sturgeon Lake New Recommended Plan place holder Depth (feet) Value High : 0 Low : -22 USGS Bathymetry Data Collected

20 UMR Pool 3 - Sturgeon Lake SL-3 SL-4 SL Preliminary Plan USGS Bathymetry Contours from SL-5 SL-1 20

21 Lower Vermillion River

22 Mud Hen Lakes Upper Clear Lake Clear Lake Lower Vermillion River Backwater Lakes Birch Lake Pickerel Lake Goose Lake Wildcat Lake

23 Carter Slough Spot Dike High Flow Inlet Mud Hen Lakes Outlet