Building with Nature Innovation program 2008-2012 Jan van Dalfsen Deltares Samen investeren in de Eems-Dollard Nieuweschans, 1 December 2011 Engineers dream, biologist’s nightmare? enhanced Afsluitdijk? Happisburgh, UK Mississippi Delta Deep Water Navigation Channel Yangtze Estuary, China Biologists and engineers have a different view on the world….. Beautiful habitat! My god, this dike needs to be improved! PARADIGMA SHIFT What can we do for nature? What can nature do for us? Building with nature? can we let nature do part of the work ... young youngdune duneformation formation while creating new new opportunities for itself? Delfland sand engine Buiding with Nature Concept & Principles … a philosophy … use the dynamics of the natural ecosystem while working on (water-related) infrastructure to add new nature … a mission … show that it is possible: developing infrastructure and at the same time creating opportunities for nature Experiences and trends in the market of dredging & construction Initiation • Complex society, complex projects • Restrictive environmental legislation • Long lasting procedures Design • More responsibility with contractor • Mitigation measures or compensation plans • Protecting sensitive environments, integrated approach Realisation • Extensive environmental management plans and extensive monitoring requirements Building with Nature Initiative of the Dutch dredging industry (Boskalis & Van Oord) How can advanced knowledge about ecosystems and cause-effect relationships be made available and generally applied? • lead to more appropriate ecological norms and standards • identify ecological opportunities for large, infrastructural projects in natural systems, • increase social and political acceptance of these projects The goal is to encourage a more “pro-active” approach to project design rather than a “reactive” approach to legislation and EIA procedures. consortium INDUSTRY dredging firms consultancies offshore industry NGO’s GOVERNMENT I&E – DG Water I&E – Rijkswaterstaat Municip. Dordrecht ~30 mio RESEARCH INST. Deltares IMARES Alterra 2008-2012 ACADEMIA TUD/UT/WUR NIOZ NIOO-CEME Process •Numerical modeling •Laboratory studies •Field studies Field sites Test proof principle Small-scale pilots researchers consultants builders vision on delta development, judicial & political environment 10-20 yr cycle incentives & alliances monitor, analyze and adapt system managers Conceptual design •Holland sandy coastal defense •Noordwaard-case Real scale application Embedding in policies, programs and project process Continuum of concepts Soft solutions Hybrid hard-soft mix non tidal/ tidal more space, no dike flexible and cost-effective Hard solutions less space, dike less flexible, extra investment Galgeplaat shoal nourishment Delfland coast Sand Engine ES: oyster reefs as shore protection ‘rich levee’ IJsselmeer foreshore nourishment Markermeer eco-levee Noordwaard: willow forest foreshore Eastern Scheldt underwater garden focus on ecosystem functioning focus on infrastructure development 4 Examples Nature incl. design Eco-engineering Example 1 Sand Engine Delfland Pilot Sand Engine Delfland: 100-150 ha, 21,5 mln m3 • One Mega Nourishment vs long term annual nourishment schemes • Minimum impacts on ecosystem • Natural redistribution of sand along coastline • Smart design to promote nature development • Innovative: Engineers and ecologists team up • Are we able to predict? Are we able to manage? Artist impression of development – not based on science Example 1 15-03-2011 11-05-2011 28-03-2011 09-08-2011 (One month after completion) Example 1 Rapid changes of morphology Sand Engine Delfland: Where are we now? 26-07-2011 09-08-2011 09-08-2011 09-08-2011 Vegetation 09-08-2011 • Major changes in first weeks after completion • Baseline monitoring 2012-2016 in place, extension foreseen • Pilot experiment attracts lot of attention • Coastal Zone Management interest • Research interest (De Vries, De Schipper) • Role model for public/private collaboration on innovations in CZM Gelobte melbe – very rare Wadden Sea Soft Safe Dike: saltmarsh/dune/dike hybrid solution Example 2 Scale: 500 m wide 30 km length Debate: Technical feasibility cost- benefits conflicts with Natura 2000 Example 3 Innovation: green wave damping Clay dike dike ‘fort Steurgat’ will be lower than traditional design 11.0 HS0 1.00 VF000 10.0 0.90 VF070 9.0 0.80 VF240 8.0 We garantee 80% wave reduction Wave Height (m) VF490 Wave reducing willow-tree plantations Low cost - low tech Deltares concept and design has been officially approved as primairy barrage with a 1/2000 safety level and will be integrated in a 300 MEuro project RWS-RVR, Waterschap Rivierenland, Deltares 0.70 0.60 7.0 6.0 0.50 5.0 0.40 4.0 0.30 3.0 0.20 2.0 0.10 1.0 0.00 -20 -10 0 10 20 30 40 x (m) 50 60 70 80 90 0.0 100 Ground level (m) NAP 1.10 Example 4 Coastal protection with oyster reefs • Involves use of eco-engineers to mitigate erosion of tidal flats in Eastern Scheldt • Ecosystem engineers such as reef building oysters can protect tidal flats from erosion, reduce wave energy, trap sediment, form diverse habitats, …and protect dikes • The use of oyster reefs is successful if they are self-sustainable and stabilize tidal flats erosion Example 4 Aim: Reduce erosion of intertidal areas 1. testing of different materials and cages in small-scale experiments => use of gabions most promising 2. small scale pilot June 2009: gabions filled with oyster shells Schanskorven gevuld met oesterschelpen 8m 2m 4m 1m 2m 6m 6m 12m 100 m2 11000 kg oyster shells laagwaterlijn 1m 6m 6m 12m Example 3 Large-scale experiments (2010) 3 reefs, 400 m3 oyster shells each Example 3 Oyster reefs: Where are we now? • Small-scale pilot positively evaluated • Gabions with oyster shells stable • Local sedimentation / reduced erosion • Oyster larvae settle & grow on reef • Lage-scale pilot realized in 2010 • In 2011: Less spat than envisaged • Morphological effects evident during storm events! 22 Sep 2009 Settled oyster larvae 28 Sep 2010 BwN & the Ems-Dollard Estuary Nature Building BwN Society Problems Human have influenced the estuary over a long time, but since 50 (100) years at the scale of the whole estuary Situation 1926: Herrling & Niemeyer, 2008 Situation 2002: Deltares, 2010 The main channel diameter is at present too large irt the total tidal water flux, while as a result of the canalisation and deepening its currents have increased The tidal amplitude is asymetrical, resulting in a net silt import. Due to the high currents this is continously brought into suspension, causing high turbidity and low O2 levels Small interventions will not succeed in recovery But: its Natura 2000 area! Ems- Dollard: options To reverse the current situation the channels should be narrowed and more rough: less deep is yet no option. Additional the mudflat area should be increased BwN soft solutions need space (and time), cost effective hard solutions are less flexible, extra investments, direct Natura 2000 limits solutions in the estuary itself so options could also be sought at the yet fixed the borders focus on the condition of the Ems-estuary seek win-win-win no net loss is too meagre substantial improvement of condition: • nature • biodiversity • safety • maintenance Ems and harbors Mogelijke oplossing 1: Geulwandsuppletie met verhoging van de ruwheid van de geul Voordelen: - verkleining getijhoogten, snelheden & ?-asymmetrie minder slibbezwaar (?); extra eb- en vloedscharen - minder baggertransport. Huidige baggeractiviteiten ca. 7 Mm3/jr Mogelijke oplossing 2: uitbreiding intergetijde plaatareaal (in combi met 1) Voordelen: - invloed op getijasymmetrie (aanvullend: zoetstroom beinvloeden?) - minder slibbezwaar - meer plaatareaal natuurlijker Keileem Oplossing 3: Kwelderwal voor Delfzijl als voorbeeld van een hybrid soft oplossing Marconi werkatelier 24-3-2011 Segmenten in de zeekering Delfzijl Voolhok Schermdijk Voolhok: condities voor kwelderwal met kwelderwerken ongunstig vanwege geul Concept kwelderwal Huidige schermdijk Overhoogte dus voldoende veilig Huidige dijk wordt „ingepakt‟ Kwelderwal is begroeid en levert meerwaarde voor landschap, recreatie en natuur Kwelderwal Zand en/of klei Nieuwe kwelder Kwelder beschermt ‘wal’ onder normale condities, dus minder onderhoud Kwelder levert slibberging en slibvang, natuurwaarde Ecologische potenties kwelderwal 60 hectare +7.35 aanleg groei 2060 +5.50 0 1 +7.67 2 +7.69 +5.67 3 +4.34 Voldoende veilig geen versterking nodig 4 +8.44 +8.53 5 +8.56 • Robuuste bijdrage aan buffer voor ZSS en klimaatverandering • Toevoeging diverse zachte intertidale habitats in systeem gedomineerd door harde kusten. • Toevoeging primaire productie in kwelder en nieuw intergetijdegebied • Hoogwatervluchtplaats vogels en vastlegging nutrienten, slib en CO 2 • Waarde voor veiligheid en natuur en landschap en recreatie (4 x win!) Focus op condition Ems-estuary win-win-win situatie seems possible: 1) substantial improvement of condition Ems-estuary situation Ems 1936 2) reduction of tidal amplitude and currents Safety: Deltaprogramma Waddengebied 3) changes in tidal asymetry and reduction of siltation: Rijke Waddenzee 4) limitations for shipping ??? Conclusions Challenges for sustainable development of surface water infrastructure • BwN solutions are available and realistically feasible - Multi-disciplinary collaboration & stakeholder interaction pays off! • Key challenge: Application in real-world projects - BwN solutions should be competitive ($$$) - BwN solutions should be embedded in regulatory systems - Procedure to assess robustness during extreme conditions - Responsibility for keeping BwN solution in condition - BwN solutions should be incorporated as adequate alternative in early stages of project development / design cycles • Demands strong involvement of government policy, regulation and agency practices Conclusions II • They are generic and pratical • They are cost effective • They fit within legal constraints • They have been realized with numerous partners from government, engineering, construction and research organizations So far: BwN received very positive attitude from dredgers, the client & authorities. Without this: no Pilots at all! Guiding principle BwN after 2012 From “Show that it Works” To “Make it Happen”
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