Riparian Ecosystems and Climate Change: the Value of Floodplains along the River Elbe

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1 Climate Change and Nature Conservation in Europe - an ecological, policy and economic perspective June 2013, Bonn, Germany Riparian Ecosystems and Climate Change: the Value of Floodplains along the River Elbe Alexandra Dehnhardt, Malte Grossmann, Volkmar Hartje Mathias Scholz Dietmar Mehl TU Berlin, Environmental and Land Economics Helmholtz Centre for Environmental Research, UFZ biota, Institut für ökologische Forschung und Planung

2 Outline 1. Introduction Ecosystem services of natural floodplains Riparian ecosystems and climate change Economic value of floodplains 2. Case studies Ecosystem functions and services of floodplains in Germany Economic value of floodplain restoration along the German river Elbe 3. Concluding remarks Alexandra Dehnhardt Environmental and Land Economics

3 Introduction Riparian ecosystems provide a wide range of services with value for human society Attractive landscapes for recreation (cultural services) Hot-spots for biodiversity (supporting services) Water quality improvement and flood control (regulating services) Functions and services are only provided by intact, near-natural ecosystems Intensive land use and settlement Straightening and embankment About % of the original floodplain area is disconnected ; only 10 % of the remaining floodplains are in a natural condition (Status report of floodplains 2009) increasing flood risk and a number of ecosystem services affected Former and topical extreme flood events German Environment Minister calls for rethink in flood protection: give rivers more room to buffer their floodwaters, if necessary through relocation of dikes. Political change to an integrated flood risk management considering the benefits provided by ecosystems Alexandra Dehnhardt Environmental and Land Economics

4 Impacts (-) Climate Change and Nature Conservation in Europe - an ecological, policy and economic perspective - June 2013, Bonn Climate change and riparian restoration Climate Change Adaptation actions Mitigation actions Riparian Ecosystems adaptive capacity (+) Floodplain restoration Regulating services Flood protection Climate regulation Benefits from reduced flood risk Benefits from reduced greenhouse gas emissions Nutrient retention Biodiversity and habitat Recreation and aesthetics Benefits from increased water quality, recreational value and nature conservation Economic perspective: considering the value of multiple ESS in policy-making

5 Ecosystem functions and services of floodplains in Germany - Case study I Quantification and assessment of ecosystem functions and services of large rivers in Germany Flood retention Nutrient retention Carbon stocks and carbon sinks Habitat function (biodiversity) Funded by the German Federal Agency for Nature Protection (BfN) Study area and data Nationwide inventory of loss and status of German floodplains 15,000 km 2 along 79 rivers (former and active floodplains and rivers) Source: Scholz, M., Mehl, D., Schulz-Zunkel, C., Kasperidus, H.D., Born, W. & K. Henle (2012): Ökosystemfunktionen von Flussauen biota - Analyse und Bewertung von Hochwasserretention, Nährstoffrückhalt, Kohlenstoffvorrat, Treibhausgasemissionen Institut für ökologische Forschung und Planung GmbH und Habitatfunktion. Naturschutz und Biologische Vielfalt 124, Bonn. biota

6 Results: flood retention and carbon storage Flood retention Hydro morphological structure and flooding characteristics not available nationwide; high degree of uncertainty in terms of potential damage Qualitative assessment of the loss of flood retention potential Carbon storage and greenhouse gas emissions Significant potential for carbon storage and sequestration of greenhouse gas emissions in floodplain soils Peatlands as an important source of greenhouse gases due to intensive land use Calculated carbon stock of active floodplains: 158 mill t: 70% in organic soils of peatlands, 26% in mineral alluvial soils, 4% in terrestrial soils 15.4 mill t total storage in alluvial forests in active floodplains Land use change ( riparian forests) will have a significant effect for climate change mitigation biota 29% 14% 9% 27% 21% Institut für ökologische Forschung und Planung GmbH very low low distinct high very high biota

7 Economic value of restored floodplains along the German Elbe - Case study II Assessing the economic effects of two alternative strategies within an integrated floodplain management Large scale floodplain restoration ( room for the river ) due to dike relocation dike strengthening + controlled polder is regarded in a cost-benefit analytical framework River stretch Number of Polder area Relocation Option Description Applying an ecosystem service (Elbe km) approach to sites estimate the (ha) economic value area of (ha) the multiple benefits: flood water retention (hydrological service), nutrient retention DR I Dike relocation large ,659 (biochemical service), biodiversity (ecological service) DR II Dike relocation small 120, ,432 Funded by the German Federal Agency for Nature Protection (BfN) P I Controlled polder large ,576 P II Controlled polder small ,248 0 Study area P (e) II Polder with ecological flooding ,248 0 P+DR Multifunctional ,143 3,402 P(e)+DR Multifunctional, ecological flooding ,143 3,402 Source: Grossmann, M., Hartje, V. & J. Meyerhoff (2010): Ökonomische Bewertung naturverträglicher Hochwasservorsorge an der Elbe, Naturschutz und Biologische Vielfalt 89, Bonn.

8 Benefits of flood risk reduction Assessing the avoided average annual flood damage Estimating the flood risk (probability of a (extreme) flood event combined with the associated expected damage) Comparing the benefits (with and without measures) in terms of the difference between average annual damage 1. Estimating downstream effects of planned and unintended retention on peak water level on a large scale: 1D-hydraulic routing model, inundation model for dike breaches / dike overtopping 2. Estimating damages: macro-scale approach; assessing the resulting flood damage as a function of inundation depth and land use classes Source: de Kok, J.L. & M. Grossmann (2010): Large-Scale assessment of flood risk and the effects of mitigation measures along the Elbe River, Natural Hazards (52),

9 Avoided average annual flood damages Programme Restored floodplain area Avoided average Total area Controlled polder annual damage ha % ha -1 DR L 34, DR S 9, P L 25, ,015 P S / P (e) S 3, ,120 P+DR / P (e) +DR 7, ,825 Source: de Kok, J.L. & M. Grossmann (2010): Large-Scale assessment of flood risk and the effects of mitigation measures along the Elbe River, Natural Hazards (52),

10 Distribution of costs and benefits of polders along the river trajectory Only upstream polder (small scale) Large scale polder Malte Grossmann, Volkmar Hartje Environmental and Land Economics

11 Results of the cost-benefit analysis (Net present value) Focus on flood risk reduction Positive net present value only for alternatives with controlled polder Source: Grossmann, M., Hartje, V. & J. Meyerhoff (2010): Ökonomische Bewertung naturverträglicher Hochwasservorsorge an der Elbe, Naturschutz und Biologische Vielfalt 89, Bonn.

12 Results of the cost-benefit analysis (Net present value) Considering the benefit estimates of multiple ecosystem services Positive net present value for all alternatives Source: Grossmann, M., Hartje, V. & J. Meyerhoff (2010): Ökonomische Bewertung naturverträglicher Hochwasservorsorge an der Elbe, Naturschutz und Biologische Vielfalt 89, Bonn.

13 Results of the cost-benefit analysis: distribution along the river Elbe Only dike relocation (large) Only dike relocation (small) NPV: net present value (3%) PC: project costs SC: saved maintenance costs FD: avoided flood damage BD: willingness-to-pay for biodiversity NR: benefits of nutrient retention Malte Grossmann, Volkmar Hartje Environmental and Land Economics

14 Concluding remarks Large-scale strategies of floodplain restoration contribute to Climate change adaptation and mitigation Flood risk management (rather than focussing only on protection) to meet the demands of the EU Flood Directive Nature protection to meet the demands of the FFH Directive Achieving the water quality objectives of the EU Water Framework Directive Exploring possible synergies between different policy goals integrated management Multidimensional perspective necessary Floodplain restoration might not be not economically advantageous looking from only a flood risk or water management perspective: costs of restoration high, benefits with regard to a single target comparatively low Dike relocations as an integrated strategy to nature conservation and flood protection are economically advantageous: benefits outweigh the costs Economic valuation and cost-benefit analysis suitable to include secondary benefits To improve integration of ecosystem services into (climate change) policy-making, still more attention is needed for the quantification of the effects as well as for the benefit estimates Alexandra Dehnhardt Environmental and Land Economics

15 Thank you for your attention. Alexandra Dehnhardt

16 Nationwide inventory of loss and status of German floodplains Status of active floodplains Auenzustandsklassen Veränderung: sehr gering gering deutlich stark sehr stark nicht bewertet Source: ustandsbericht.html