Island Design Presentation for the UMRS EMP Regional Workshop by Jon Hendrickson Hydraulic Engineer Regional Technical Specialist, Water Quality and Habitat Restoration August 17 19, 2005
Project Delivery Team Define Objectives for Desired Ecosystem Condition Define Design Criteria to Achieve Objectives Define Performance Metrics Identify Actions Needed to Meet Design Criteria and Performance Metrics Identify Modeling Needs Identify Pre-project Monitoring Habitat Benefits Evaluation Design Project Engineering Considerations Post-project Physical & Biological Response Monitoring Cost Benefit Analysis Cost Reducing Measures Lessons Learned Plans & Specs Construction 18 Aug 05 2
Chapter Development Discussed at the 20-21 February 2002 EMP Workshop in St. Louis, MO The large river habitat project engineering handbook: Where is it? Island Design Handbook was completed in April 2005 This Handbook was modified to become the Island Design Chapter in the Current Handbook 18 Aug 05 3
Chapter Use Design Criteria are listed for 6 design categories: Layout Elevation Width Side Slope Topsoil and Vegetation Shoreline Stabilization Each design category is organized into 4 design disciplines Geomorphology Engineering Constructability Habitat Design criteria are referenced to Physical Attributes Habitat Parameters Engineering Considerations Lessons Learned that were used to develop the design criteria 18 Aug 05 4
Chapter Outline Resource Problem E, D, & C Data for Existing Projects Lessons Learned Design Criteria 18 Aug 05 5
Resource Problem (Lower Reach of Pool) Lock and Dam Construction Action Physical Response Biologic Response Hydraulics Wind Fetch and Wave Action Increased Water Surface Elevation Increased/Stabilized Floodplain Flow Increased Main Channel Flow Decreased Secondary Channel Flow Decreased Water Quality Sediment Resuspension Increased Light Penetration Decreased Geomorphology Island Erosion Increased Sediment Deposition Rate In Floodplain Increased Sediment Transport Decreased in channels Pattern of Habitats Island Habitat Decreased Floodplain Plant Communities Species Composition, Density Degraded Isolated Floodplain Habitat Decreased Degraded/Reduced Sandbar/Mudflat Habitat Delta Habitat Channel substrate Plants and Animals Migratory Birds, Raptor Habitat Degraded Invertebrate Populations Reduced Backwater Fish Habitat Degraded Waterfowl Habitat Degraded Channel Maintenance Dredge Cut Location and Volume Altered 18 Aug 05 6 Jon S. Hendrickson, 04/15/05
E, D, & C Data Sheltered Side Exposed Side f a b c d e Berm Height, 2 over ave. w.s. elev. Ave. w.s. elev. Topsoil (Fine Material) a/2 e/2 Random Fill Granular Fill Existing Bottom Varies As-built berm 1V:3H Final Berm 1V:10H Ave. w.s. elev. Littoral Zone Beach Woody Vegetation Grasses Woody Vegetation Beach Littoral Zone Approximate Limits of Vegetation Zones 18 Aug 05 7
E, D, & C Data Table 3. Island Cross Section Dimensions. The dimension a through f correspond to those shown in figure 2 Project a b c d e f Height above Island Length and Side Normal Pool and Reach Description Slopes Flood TOR (feet) Year Weaver Bottoms 0 32 100 32 0 164 8, 80-yr 1:4 1:4 8700 1986 Lake Onalaska 0 18 50 9 20 100 6, 20-yr 1:3 1:3 3900, 3 islands at 1300 feet each 1989 2100, from head Pool 8, Phase I, Stage 1 Horseshoe Island Pool 8, Phase I, Stage 2 Boomerang Island 0 20 50 30 30 130 4, 10-yr 1:5 1:10 down each leg 1989 0 20 75 30 30 155 4, 10-yr 1:5 1:10 800, middle west leg 1989 0 20 30 40 0 90 4, 10-yr 1:5 1:10 600, lower west leg 1989 30 12 50 12 30 134 3.8, 10-yr 1:5 1:5 7000 1992 20 12 50 12 20 114 3.8, 10-yr 1:5 1:5 700, several reaches 1992 30 10 50 40 0 130 3.8, 10-yr 1:4 1:10 500, large fines section 1992 0 25 30 25 0 80 5, 17-yr 1:5 1:5 500, lower Horseshoe Island. 1992 18 Aug 05 8
E, D, & C Data Table 8. Costs of the pool 8, Phase I and II and Polander Lake Island projects. Project Year Constructed Feature Length (feet) Cost (dollars) Cost/Foot Pool 8, Phase I, 1992 Stage 2 Earth Islands 9,600 1,456,000 $151 Earth Islands 10,600 1,755,000 $165 Pool 8, Phase II 1999 Rock Sills 2,500 722,000 $288 Seed Islands 1,280 169,000 $132 Polander Lake, Stage 2 2000 Total Cost 2,646,000 Earth Islands 9,200 1,897,000 $206 18 Aug 05 9
Lessons Learned Lessons Learned are described in seven tables, one for each of 6 design categories, and a seventh table for constructability. Layout Elevation Width Side Slope Topsoil and Vegetation Shoreline Stabilization Constructability 120 Lessons Learned are listed in these tables 18 Aug 05 10
Design Criteria Design Criteria are described in six tables, one for each of the design categories Physical Attributes Lessons Learned Habitat Parameters Engineering Considerations Design Criteria 18 Aug 05 11
Example For Design Criteria 2.c Category 2: Island Elevation Design Criteria 2.c Rock islands or sills may replace portions of earth islands to provide floodplain flow for more frequent floods. These features should have a lower elevation than earth islands so flow first occurs over the rock, reducing hydraulic forces across the earth islands during later stages of the flood. Reference: Physical Attribute 5,7; Lessons Learned 2.E.1, 2.H.1; Engineering Considerations 2, 3 18 Aug 05 12
Design Criteria 2.c Referenced to Physical Attributes Physical Attribute 5: Balanced fine and coarse sediment budgets. River reaches export fine and coarse sediment at rates approximately equal to sediment inputs.. Physical Attribute 7: A functional floodplain. On average, floodplains are inundated once annually by high flows equaling or exceeding bankfull stage. 18 Aug 05 13
Design Criteria 2.c Referenced to Lessons Learned 2.E.1, Pool 9 Islands, 1994 Islands constructed to lower elevations are not exposed to the severe erosive forces associated with floods. These islands, which consisted of rock mounds, have been overtopped several times and show minimal damage. 2.H.1, Pool 8, Phase II, 1999 The low rock sills combined with a stepped down island design resulted in a stable project during the 2001 flood, when the islands were less than 2 years old and didn t have well established vegetation. The rock sills were set at the lowest elevation. 18 Aug 05 14
Design Criteria 2.c Referenced to Engineering Considerations Engineering Consideration 2: Reducing sediment loads but increasing sediment trap efficiency: Islands reduce the flow of water and sediment to backwater areas or selected parts of backwater areas. This decreases flow velocities, which is usually a necessary step in improving habitat. However, the trap efficiency of the backwater area sheltered by the island is increased so sediment that does enter is more likely to deposit there. Engineering Consideration 3: Island elevations and bankfull flood elevations in lower pools - River restoration efforts usually attempt to establish riverine flow conditions where flow is conveyed in channels for low and moderate flows and significant floodplain flow occurs only after the bankfull flood level is exceeded. Islands, in their most basic form, are the natural levees that separate channels from floodplains. It follows that island height should correspond to bankfull flood levels.. 18 Aug 05 15
POOL 8 ROCK SILL, 1999 18 Aug 05 16
Islands and Future Habitat Restoration EMP: Five Large Island Projects Being Developed HNA: Create or Restore 24,000 Acres of Island Habitat EPP: Numerous Islands NESP Workshops: 1/3 of Objectives Linked to Islands 18 Aug 05 17
Spring Lake: Under Construction 2005 18 Aug 05 18
Swan Lake Islands, Illinois River 18 Aug 05 19
Swan Lake Islands, Illinois River 18 Aug 05 20
Swan Lake Islands, Illinois River 18 Aug 05 21
End Island Talk Questions Comments Lessons Learned
Start Tributary Restoration Talk
Bed Material Budget, St. Paul District, Anoka, Minnesota to Guttenburg, Iowa 900,000 800,000 700,000 600,000 500,000 400,000 300,000 200,000 100,000 0 860.0 850.0 840.0 830.0 820.0 810.0 800.0 790.0 780.0 770.0 760.0 750.0 740.0 730.0 720.0 710.0 700.0 690.0 680.0 670.0 660.0 650.0 640.0 630.0 620.0 610.0 Anoka, MN Minnesota River L/D 2 L/D 3 Cannon River Chippewa River L/D 4 Zumbro River L/D 5 L/D 5A L/D 6 L/D 7 Root River L/D 8 Upper Iowa River L/D 9 Wisconsin River L/D 10 Bed Material Load (tons/year) Tributary Restoration = Eliminate Spikes in Sediment Spikes in Sediment Budget at Reach 3 Tributaries Reach 1 Reach 2 Reach 3 Lake Pepin River Mile 18 Aug 05 24 One Sand Corps Budget, Serving St. Paul District the Army CSU and Data the Nation
New Projects Upland Sediment Control/ Tributary Modifications 18 Aug 05 25
Start River Training Structure or Secondary Channels Talk
Increased Floodplain Discharge Pool 8, Main Channel Discharge, 1996 Conditions Main Channel Discharge (Percent of Total River Discharge) 100.00 90.00 80.00 70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 Lock and Dam 8 Habitat Restoration In the Lower Reach Dredging Reach Root River Bed Material Load (10,000 tons) Lock and Dam 7 680.0 682.0 684.0 686.0 688.0 690.0 692.0 694.0 696.0 698.0 700.0 702.0 River Mile Main Channel Discharge 18 Aug 05 27
Secondary Channel Mods 18 Aug 05 28
Rock Partial Closure at Lansing Big Lake 18 Aug 05 29
Earth Closure 18 Aug 05 30
Start More Island Images
Historical Changes in Pool 8 Island Erosion Lower Pool 8 1939 Lower Pool 8 1989 18 Aug 05 32
Stoddard Bay Islands = Dredging 300,000 Yd 3 The form, function, and habitat value of Stoddard Bay was degraded due to island erosion and wave action Rock Sills Islands The habitat value was restored in 1999 by constructing islands 18 Aug 05 33
Lake Onalaska: Sheltered zone downstream of islands Black River Plume Heavy rainfall, followed by sediment laden tributary inputs elevated Mississippi River sediment concentrations on this day. Each of the three islands has a zone of influence where clearer water persists. 18 Aug 05 34
Polander Lake: Constructed 2000 18 Aug 05 35
Polander Lake Interior wetland 18 Aug 05 36
Island Cost = $200/ft Cost Breakdown 30% Granular Fill 25% Fines 25% Shoreline Stabilization Riprap: 1/5 of s.l. length Biotechnical: 2/5 of s.l. length Vegetative: 2/5 of s.l. length 10% Mob-Demob 10% Turf, Plantings, Geotextile 18 Aug 05 37
ISLAND CROSS SECTION HABITAT AQUATIC PLANTS & MUDFLATS WILLOWS & BEACH TREES & GRASSES DIMENSION MUDFLAT WIDTH IS 20 TO 200 FEET BERM WIDTH IS 30 TO 60 FEET TOP WIDTH IS 30 TO 80 FEET 2 TOPSOIL SAND FILL MUD FLAT Existing Bottom TYPICAL ISLAND ELEVATION EQUALS 3-YEAR FLOOD HEIGHT 18 Aug 05 38