Mississippi River Ecohydrology Past, Present and Future

Transcription

1 Mississippi River Ecohydrology Past, Present and Future Dr. Paul J. DuBowy USACE Mississippi Valley Division Vicksburg, Mississippi USA

2 Ecosystem Function Mississippi River Ecohydrology Ecosystem Rehabilitation Historical Mississippi River Current River System Ecosystem Structure

3 Mississippi River Catchment Lake Traverse Old Faithful Allegheny River New Mexico Atchafalaya Basin Great Smoky Mountains

4 Mississippi River Mississippi Second longest river in North America (2,350 miles) 2,348 Miles Long fifth longest in world longest river flowing southward in world Mississippi-Missouri- Madison = fourth longest in world (3,900 miles) exceeded only by Nile, Amazon and Yangtze Rivers Lake Itasca Northern Minnesota Wisconsin/Minnesota L&D 14 Chain of Rocks St. Louis Old Man River Old River Control Complex Head of Passes

5 USGS Circular 1133, 1995

6 100% 80% 60% 40% 20% 0% Main Channel Secondary Channel Tertiary Channel Contiguous Backw ater Isolated Backw ater Island Sand Tributary Channel 100% 80% 60% 40% 20% Upper Mississippi River aquatic habitat relative abundance by river mile. Historic Mississippi River Commission (ca. 1890, top) and recent (1989, bottom) data. Sandbars now absent and islands reduced. Courtesy C. Theiling, MVR. 0% Main Channel Secondary Channel Tertiary Channel Contiguous Backw ater Isolated Backw ater Island Sandbar Tributary Channel

7 Weaver Bottoms

8 Grand Isle

9

10 Saucier 1974

11

12 Vicksburg Discharge/Stage

13

14

15 Spawning Habitat

16 Neotropical Migrants

17 Black Bear

18 Lord God Bird

19 Sandbar

20 Gravel Bar 241species of fish in Mississippi River watershed 292 bird species use Mississippi Flyway 57 species of mammals 45 species of reptiles and amphibians 40 species of mussels Numerous invertebrate species

21 Early Commerce

22 Navigation 60 Semi- 1 Barge = 15 Rail Cars or trucks Water transportation moves 16% of the nation s freight for 2% of the freight cost Barges can move a ton of freight an average of 576 miles on a single gallon of fuel (TX Transportation Institute) >500 million tons of goods (peak) travel the Mississippi River each year More than 50% of America s grain exports move down the Mississippi River system

23 4,200 TRUCKS

24 Wing Dikes >730 Dikes Constructed in LMR >320 Linear Miles of Dikes Side channels now hydrologically disconnected from main river at low water (40-50% of year) X-section Forces flow into main channel

25 Great Flood of recorded deaths 700,000 refugees 162,000 homes inundated 16.6 million acres flooded

26 1928 Flood Control Act Authorized Mississippi River and Tributaries (MR&T) Project nation s first comprehensive flood control system largest flood control project in world 36,000 mile 2 LMV $13 B invested

27 Levees 3,727 miles authorized 3,486 miles to date 94% complete Bottomlands now hydrologically disconnected from river Batture lands = land between levees remaining active floodplain; much still forested 2.3 million acres

28 LMR Floodplain Courtesy LMRCC

29 Changes in Middle Miss River

30 Environmental Engineering Goals Enhance channel habitat diversity Improve diked secondary channel habitat Implement environmental engineering measures for dikes and other structures Build environmental enhancement into program Facilitate partnering among federal and state agencies and NGOs

31 Endangered Species Fat Pocketbook Mussel Pallid Sturgeon Interior Least Tern

32 Environmental Engineering Solutions Maintain secondary channels Predator protection for nesting birds Deep water and gravel bars for spawning fish Habitat diversity within dike fields Slack water/soft sediment habitats for mussels

33 Secondary Channel Monitoring Comprehensive hydrographic surveys (1960s present) trends information Net quantities of secondary channel areas and volumes at multiple river stages ID suitable channels for rehabilitation high priority enhancement opportunities

34 Hickman Bar Bend

35 Little Cypress Bend

36 Decision Rules for Notching With and without notches Stage-related changes habitat surveys species occurrence Notch dimensions elevation width

37 Dike Notching Side channels present Notches: ft wide LWRP to LWRP +5 ft

38 Mississippi +5 LWRP 97% River 90% 80% 60% Hydrograph Exceedance

39 Redman Point/Loosahatchie Bar

40 1901

41

42 Courtesy Lawrence Thomas, MVM Project Goal

43 Project Planning

44 +10 ft 0 ft LWRP 0 ft -5 ft -5 ft -10 ft -10 ft -20 ft -20 ft -30 ft > -30 ft LWRP

45 Project Design

46 Project Management

47 Project Construction

48 Notched Dikes

49 Notched Dike

50 MVM River Engineering USFWS Regional Director s Conservation Award

51 Section 2039 WRDA 2007 Projects must include plan for monitoring success of ecosystem restoration. Description of monitoring activities, criteria for success, and estimated cost and duration of monitoring (monitoring will continue until ASA- CW deems project successful).

52 Future Needs Partnering Need to move away from faith-based side-channel rehabilitation Critical need for science-based, a-priori protocols goals objectives targets metrics Adaptive Management

53