The Sigmaplan – FlandersUpdating the Flemish Sigmaplan : Large scale

flexible and sustainable river management

Waterwegen & Zeekanaal (W&Z) nvWaterways and Sea Canal

Agenda

- Introduction : Waterwegen en Zeekanaal – Sea Scheldt- The original Sigmaplan : Storm surges – Details – Current

situation- Need for an update- The updated Sigmaplan- The future- Questions

Flemish governement – Department of Public Works

Waterwegen & Zeekanaal : independent agency (plc)

Organisation

Statement

Run most of water ways and surrounding area in Flanders, taking into account all stakeholders

Encourage multifunctional use of the water Ensure safety of water ways and safety on the water Manage flooding risk

The Sea Scheldt area105 km tidal influence

Around 5.000 km2 3 million people

The Scheldt basin355 km source-to- mouth

Around 20.000 km2

10,5 million people

gemiddeld HW en LW

-1

0

1

2

3

4

5

6

7

0 50 100 150

afstand in km

doodtij LW

doodtij HW

springtij LW

springtij HW

GentVlissingen Hansweert Antwerpen Dendermonde

Dead low tideDead high tideSpring tide (low)Spring tide (high)

- Tides amplifies because of the narrowing of the riverbed around the city of Antwerp- Tides go until the shiplocks in Ghent more then 150km upstream- Unique natural values connected to the sweet water tidal conditions

Salty Sweet

Congestion by north-westerly storm Storm tide Rising water levels Flooding risk Severe consequences (damage) Combination with Rainwater runoff

upstream

Date Water level in Antwerp (TAW)

Rise by congestion

over astronomical

tide

Belgium

The Netherlands

United Kingdom

France

Immediate cause• 1953 (Dutch Deltaplan) 15500 ha flooded in Flanders • 1976 january 3rd 2000 ha flooded in Flanders

Goal• Protection of the Sea Scheldt area against flooding with a probability of 1% per century (= once in 10.000 years)

Decision• by the council - 1977, feb.,22nd - implementation of the original Sigmaplan

embankment augmentationzone 3 : 8,00 m TAW

embankment augmentationzone 1 : 11,00 m TAW

13 flood control areascirca 1.250 ha

Tidal barrierOosterweelembankment augmentation

zone 2 : 8,35 m TAW

Sigmaplan 1977

Implementation• 81 % of the 512 km planned embankment constructions along the Seascheldt and its affluents are completed• 12 of the 13 flood control areas functioning• 650 ha (1600 acres) largest flood control area Kruibeke - Bazel - Rupelmonde is under construction (end of construction 2013)

Safety level – storm with a yearly chance of occurence :• 1/70 (7,83 m TAW): current situation• 1/350 (8,24 m TAW): once CFA Kruibeke is finished• 1/10.000 (8,97 m TAW): with tidal barrier – original goal, but put indefinitely on hold in 1985 based on a cost – benefit analysis

Final Result 2013 and onwardMaximum safety level of 1/350

Sigmaplan 1977 - Need for an update - Safety

Immediate cause• VN-Conference 1992 Rio (Agenda 21): national integrated water management• Helsinki Agreement 1992: transboundary integrated water management

Goal• Develop, a water system manage and repair it• Make sure the water system functions

Scheldt estuary• Collaboration The Netherlands - Flanders• Long Term Vision Scheldt estuary (ambitions for 2030)• Three main aspects (accesibility – safety – ecology)• Flemish territory: Sea Scheldt : safety and ecology : updated SIGMAPLAN• Dutch territory: accesibility Westerschelde - Oosterschelde

Sigmaplan 1977 - Need for an update - IWM

Step 5 choice of optimal project

Step 6 Detailed project – implementation plan

Step 3 SimulationsStep 2 Buiding BlocksStep 1 Data - Models

Step 4 Social CBA

The updated Sigmaplan – the making of

The updated Sigmaplan – main principle

low probability high probability

lower consequences higher consequences

Risk = Probability * Consequence

-Probability: flooding by overtopping or failing of an embankment-Consequence: damage in euro (material infrastructure, personal)

The updated Sigmaplan – How To

• Make a sustainable river system taking into account the European directives on environmental conservation objectives

• Combine safety with ecological functions to minimise impact on current landuse

• Find areas along the river where current use has the least social benefit and develop a system of support for the agriculture sector

• Develop the local projects on a basis of local participation from an early stage to guarantee maximum social benefits for example : recreational opportunities

• Total cost estimate above 500 MEUR (2004)• Phased investment and construction between 2010 – 2030.

Projects with most impact (highest benefit) in a first phase.• Total area for nature (tidal and non-tidal) and FCAs : 5400 ha of

which more then 5000 ha future nature area of which 3000+ ha new tidal nature

• Flexibility : after 2030 with 5 reserved areas in case stormtides rise more then anticipated inn 2004 : 500 ha.

The updated Sigmaplan – Phased investments

The updated Sigmaplan – First phase 2010

Tidal nature in combination with a FCA – CRT

The updated Sigmaplan September 2011

Land acquisitions slow the project considerably (especially areas with solely ecological goals)

Temporary (…) budgetcuts since 2009

Technical designs and building permits for all 2010 FCA local projects are ready at present.

4 of the 23 2010 local projects are under construction

The construction of the rest of the 2010 local projects will start from 2012 onward, total area : 2500 ha

Preliminary studies for 2015 local projects are started, total area : 1900 ha

Next step - Integrated Water ManagementIncluding the possible improvement of inland shipping

Study underway to upgrade from CEMT IV to Va

End of the presentation

Questions ?