Chesapeake Bay Seminar Series

Size: px

Start display at page:

Download "Chesapeake Bay Seminar Series"

Sheryl Nicholson
5 years ago
Views:

Chesapeake Bay Seminar Series Coping with sea level rise in Chesapeake Bay and around the world Was the storm surge from Hurricane Isabel a taste of Chesapeake Bay s future? J.

1 Chesapeake Bay Seminar Series Coping with sea level rise in Chesapeake Bay and around the world Was the storm surge from Hurricane Isabel a taste of Chesapeake Bay s future? J. Court Stevenson Horn Point Laboratory, University of Maryland Center for Environmental Science Online broadcast at Hosted by the Integration & Application Network at the University of Maryland Center for Environmental Science integration application network

2 Coping with sea level rise in Chesapeake Bay and around the world Was the storm surge from Hurricane Isabel a taste of Chesapeake Bay s future? The last house on Holland Island Image: J.C. Stevenson Prof. J. Court Stevenson

Storm surges threaten many regions (London, Holland, Venice) Management responses in

3 Outline Relative sea level is rising in Chesapeake Bay Sea level rise can be balanced by sediment/organic accretion Dams can reduce sediment supply (Three Gorges Dam, China) Storm surges threaten many regions (London, Holland, Venice) Management responses in Chesapeake to sea level rise and storm surges include using dredged sediments & living shorelines

Isabel storm surge provides impetus to understand underlying

threat to man-made made structures along the Atlantic shoreline.

wake-up call to the public that better strategies are needed to

4 Isabel storm surge provides impetus to understand underlying processes Isabel demonstrated how a minor hurricane can pose a threat to man-made made structures along the Atlantic shoreline. In view of global warming and sea level rise, Isabel should be a wake-up call to the public that better strategies are needed to cope in the future. Photo: Don Merrit,, UMCES Raleigh News and Observer, Sept 2003

5 Relative sea level rise =

6 Sea level is rising in Chesapeake Bay Baltimore sea level Source: Permanent Service for Mean Sea Level

7 Sea level rise can be balanced by sediment/organic accretion Marsh expansion and peat formation Marsh loss (drowning) Photo: E.W. Koch, UMCES

development over accumulating sediment on a sand flat & over the upland under the

8 Intertidal vegetation is extremely sensitive to sea level fluctuations Salt marshes in temperate regions Mangroves in tropical regions Redfield s model for salt-marsh development over accumulating sediment on a sand flat & over the upland under the influence of rising sea level (Redfield, 1972). HW refers to mean high water at various times during development

9 From: Stevenson et al Mar. Geol. 67: Regions where sea level rise exceeds accretion will 'drown' marshes Sediment budget (MT yr - 1 ) for Blackwater River Inputs Outputs Blackwater River Lower Blackwater at Shorter's Wharf Ebb tides 1,070 Ebb tides 766,000 -Flood tides Flood tides 41,400 Net input 570 Little Blackwater River Ebb tides 6,580 -Flood tides 1,880 Net input 4,700 Total riverine input 5270 Total tidal output 724,600 Net system export -719,330

10 Saltmarsh management implications: Biotic grazing removes biomass Photo: Chesapeake Bay Program Photo: G. C. Kelley Nutria Snow goose Photo: J.C. Stevenson

Saltmarsh management implications: Harvesting removes biomass Gathering Hay Before a Storm,, 1862 Oil Painting by Martin Johnson Heade Antiques Magazine,, May 2001.

11 Saltmarsh management implications: Harvesting removes biomass Gathering Hay Before a Storm,, 1862 Oil Painting by Martin Johnson Heade Antiques Magazine,, May Salt haying was common along the coast in the 1800s. However, sea s level began to take its toll in the 20 th century and eventually dikes were put up on the seaward sides in NJ to reduce tidal action. This promoted peat subsidence

Saltmarsh management implications: Sediment

applied to eroding marshes (Louisiana) Cahoun and

Stevenson Salt marsh (Sept 2003) on Blackwater

12 Saltmarsh management implications: Sediment accretion can be enhanced Dredge material can be applied to eroding marshes (Louisiana) Cahoun and Cowan, 1988 Cahoun and Cowan, 1988 Photo: J.C. Stevenson Salt marsh (Sept 2003) on Blackwater River one year after thin-layer application of dredged material.

Chesapeake over the last several decades Appears to promotes sediment accretion Photo: J.C. Stevenson Diagram: K.

13 Saltmarsh management implications: Phragmites control removes biomass Phragmites australis is a C-3 C 3 plant and as such grows more vigorously under enhanced CO 2 environments Introduced variety encroaching on marshlands of the Chesapeake over the last several decades Appears to promotes sediment accretion Photo: J.C. Stevenson Diagram: K. Saltonstall Stevenson et al. (2001) Salt marsh (Sept 2003) on Blackwater River one year after thin-layer application of dredged material.

14 Dams can remove sediment supply Photo: J.C. Stevenson Photo: J.C. Stevenson Photo: J.C. Stevenson

15 Impact of large dam on coastal features may be profound Shanghai Iimage: : NASA/MODIS Photo: J.C. Stevenson Yangtze River flooding in Hunan Province Former school flooded for Three Gorges Dam

16 Storm surges threaten many coastal regions: European examples Images courtesy NASA Visible Earth London Rotterdam Venice

all Whitehall having been drowned" Samuel Pepys in his diary 7 December 1663 Whitehall

17 Historical storm surges noted in London by Samuel Pepys "There was last night the greatest tide that was ever was remembered ered in England to have been in this River all Whitehall having been drowned" Samuel Pepys in his diary 7 December 1663 Whitehall from St James's Park by Peter Tillemans Original owned by His Grace the Duke of Roxburghe,, UK

There were generally cooling temperatures from 1,000 AD to 1600s.

18 'Little Ice Age' of medieval Europe was cooler with lower sea level The Frozen Thames by A. Hondius Thousand year air temperature trends suggest about ½ degree change over last century and a half but why wasn t this more? There were generally cooling temperatures from 1,000 AD to 1600s. The curve suggests an upward trend in the 1700s and then cooling again about 1815 and then a steady increase as fossil fuels became more available and land clearance was widespread. 'Little Ice Age' Data: Climate Research Unit, University of East Anglia, UK

Tide gates on Thames River used to protect London from storm surge North Sea Flood of 1953 drowned 160,000 a.

conjunction with a flood barrier with movable gates built b across the river Thames Barrier and Flood Protection Act 1972 to

of the Barrier started in late 1974 & operational in Oct 1982.

19 Tide gates on Thames River used to protect London from storm surge North Sea Flood of 1953 drowned 160,000 a. & killed 300 people Following 1966 report by Sir Herman Bondi,, decision was that best solution was bank raising in conjunction with a flood barrier with movable gates built b across the river Thames Barrier and Flood Protection Act 1972 to give powers to carry c it out Interim bank raising actually begun in April 1971 and completed in December 1972 Construction of the Barrier started in late 1974 & operational in Oct It was first used in Feb 1983 & officially opened by Her Majesty The Queen on 8th May 1984 Thames barrier Image: University of Nottingham, UK Institute of Engineering Surveying & Geodesy Image: Thames Barrier Park

20 The Dutch have had extensive experience in storm surge protection and coastal development Original land Reclaimed land Source: World Factbook Netherlands Government

21 Images: Cruquius Museum, Netherlands Reclaimed lands in Holland are used for agriculture Before After

22 Extensive dikes are being raised to account for sea level rise Source: Netherlands Government Source: Netherlands Government

23 Port of Rotterdam uses largest storm surge gates in the world Source: Port of Rotterdam Source: Consorzio Venezia Nuova

24 Source: Chiozzotto and Drusiani,, IWA Conference 2002 Venice is the best known case study of sea level rise

Rising sea level has led to increased flooding of Venice Annual distribution of exceptional high water events in the period 1923-1996 1996 Source: Centre for tidal forecasting

25 Rising sea level has led to increased flooding of Venice Annual distribution of exceptional high water events in the period Source: Centre for tidal forecasting of the Venice Municipality and Rafael Bras, MIT Sea level trend at Venice and Trieste in the period Source: Carbognin L, CNR, Venice, Italy, and Rafael Bras, MIT

26 St. Mark's Piazza experiences regular flooding Images: Consorzio Venezia Nuova

27 Water diversion reduced sediment delivery to Venice Lagoon Venice circa 1500 Source: Consorzio Venezia Nuova Brenta Canal Brenta River Venice

28 Net sediment transport out of Venice Lagoon Source: Consorzio Venezia Nuova

29 Sea level problems are not restricted to Venice Lagoon >2 m above sea level 0 to 2 m above sea level 0 to 2 m below sea level < 2 m below sea level Bondesan et al J. Coastal Research Vol. 11

30 Management responses to the Venice situation vary Source: Chiozzotto and Drusiani,, IWA Conference 2002

31 A massive engineering project has been initiated for storm surge protection Source: Chiozzotto and Drusiani,, IWA Conference 2002

32 Floating gates being constructed for Venice Lagoon Source: Consorzio Venezia Nuova

33 The future fate of St Mark's Piazza, Venice? Artist: Ken Brown

34 A book comparing northern Adriatic and Chesapeake Bay has been published Available from American Geophysical Union

35 In Chesapeake Bay, shoreline erosion is accelerated with sea level rise Image: J.C. Stevenson Photo: David Harp Photo: J.C. Stevenson

36 As marshes erode, buffering capacity is lost Photo: J.C. Stevenson Armoring shorelines at Cooks Pt 18 Apr 2001

37 Poplar Island is being restored using dredge material Image: USGS

Dredge material for Poplar Island comes from Baltimore The Poplar Island project will reconstruct the island to its approximate size in 1847 using 29

38 Dredge material for Poplar Island comes from Baltimore The Poplar Island project will reconstruct the island to its approximate size in 1847 using 29 million cubic meters of clean dredged material from the Baltimore Channels Federal Navigation project. Harbor approaches Image: US Army Corps of Engineers

39 Dikes created initially, followed by in-filling with dredge material Images: US Army Corps of Engineers

habitat Of the wetland, 80% is projected as low marsh (Spartina( alterniflora) ) and 20%

40 Poplar Island restoration will Poplar Island restoration will create 450 hectacres of wildlife habitat, approximately 225 ha each of intertidal wetlands and uplands create new habitat Of the wetland, 80% is projected as low marsh (Spartina( alterniflora) ) and 20% as high marsh (Spartina( patens, Distichlis spicata, etc) meadows Image: US Army Corps of Engineers

Sulfides much lower in dredge material 0.000 2.000 4.000 6.000 8.000 10.

41 Sulfides much lower in dredge material [H 2 S] m mol L [H 2 S] mm ol L Depth (cm) Tilled dredge Depth (cm) Un-tilled dredge 3H 3L 4H 4L [H 2 S] m mol L Photo: J.C. Stevenson 0 [H 2 S] mm ol L Depth (cm) No treatment Depth (cm) Reference marsh 5H 5L 6H 6L Data: Quarterly Progress Report to Port of Baltimore and MD Environmental Services, Sept 2003

42 Restored marsh does not have anoxia problems like reference marshes Temp C DO mg/l /26 6/27 6/28 6/29 6/30 7/1 7/2 Dissolved oxygen maintained above 5 mg/l Data: Quarterly Progress Report to Port of Baltimore and MD Environmental Services, Sept 2003

John Flood s Living Shoreline on South River Lateral marsh accretion along shoreline of south river farm, six years after installation of offshore 'sill' to

43 John Flood s Living Shoreline on South River Lateral marsh accretion along shoreline of south river farm, six years after installation of offshore 'sill' to reduce wave action at toe of eroding bluff Eroded bluff Offshore 'sill' to reduce wave action SAV beds Offshore sandbar Accreting marsh Photo: J.C. Stevenson

44 'Bio logs' can be used to reduce erosion in low wave activity areas Photo: J.C. Stevenson

45 Do we need storm surge barriers in Chesapeake Bay? Baltimore Annapolis Washington DC Image: USGS

46 Management responses to sea level rise need to include greenhouse gas strategy Source: IPCC

Conclusions Relative sea level is rising in Chesapeake Bay Sea level rise can be balanced by sediment/organic accretion Dams can reduce sediment supply (Three Gorges Dam, China) Storm surges

47 Conclusions Relative sea level is rising in Chesapeake Bay Sea level rise can be balanced by sediment/organic accretion Dams can reduce sediment supply (Three Gorges Dam, China) Storm surges threaten many regions (London, Holland, Venice, Chesapeake) Management responses to storm surges include reduced groundwater extraction and surge barriers; need to include greenhouse gas strategy

48 Acknowledgements MD Dept of Natural Resources US Environmental Protection Agency US Fish & Wildlife Service US Army Corps of Engineers MD Environmental Service Port of Baltimore NOAA Coastal Zone Program My publication list is on our website hpl.umces.edu For copies me Or phone , fax

49 Chesapeake Bay Seminar Series Coping with sea level rise in Chesapeake Bay and around the world Was the storm surge from Hurricane Isabel a taste of Chesapeake Bay s future? J. Court Stevenson (Horn Point Laboratory, University of Maryland Center for Environmental Science) QUESTION TIME Hosted by the Integration & Application Network at the University of Maryland Center for Environmental Science integration application network

Chesapeake Bay Seminar Series

Chesapeake Bay Seminar Series Sea level rise and coastal change: What the last several hundred years and Hurricane Isabel tell us about future coastal vulnerability in Chesapeake Bay Michael Kearney (Department