Farhana Ahmed "Learning from our futures"Presentation Transcript
Communities and Institutions for Flood Resilience Turning Tides?Learning from our futures Resilient Adaptation to Flood Risks underUrban Growth and Climate Change Dynamics Promovendus: Farhana Ahmed Promotor: Prof. Chris Zevenbergen Supervisors: Berry Gersonius, William Verbeek 2 November, 2012
Research Background• Cities are prone to hazards with 233 out of 633 cities or urban agglomerations and 663 million inhabitants vulnerable to high risk of flooding• World urban population is presently more than 50%, expected to reach 67% by 2050• Of which, 86% population in the more developed regions and 64% in the less developed regions.• Urbanization rate of 1.32% in less developed regions, is more than developed region with 0.4%• Climate change will increase precipitation and more frequent flooding events.
Adverse Effects of FloodPhysical effects – Damage to structures and – InfrastructureEnvironmental effects – Water quality through contamination of drinking water and water bodies – Public health issues and – Aesthetic influenceSocio-economic effects – Economy – Societal disruption • Within 1995-2004, flood contributed to 20% death toll • 33% economic losses
Project Background Communities and institutions for flood resilience: enhancing knowledge and capacity to manage flood risk in the Bangladeshi and Dutch Deltas Partners: Dutch institutes (Wageningen University, UNESCO-IHE) & Bangladeshi Institutes (IWFM-BUET, CEGIS) Analyze the strategies and policies of rural, urban, epistemic and policy communities to reduce flood risks and vulnerabilities Period: 2012-2016
Integration among the PhDs under WOTRO Publication and Integration process among the PhDs Dissemination Delta lessons and Water Management Practices in the Dutch-BD deltasPhD-1:Dealing with uncertainty: the deltaknowledge agendas in the Netherlands PhDand Bangladesh Thesis Urban-Rural Flood Management Practices in BD PhD-2: Assessment of rigid vs flexible flood PublicationsPhD-3: Rural climate-change adaptation adaptation and mitigation sStrategies underin Bangladesh: strengthening flood (Journals/Book) dynamic urban environment and changing climateresilient communities Adaptation and Mitigation Strategies in BD-NetherlandsPhD-4: Linking climate change adaptation Workshops/ Websiteand disaster risk reduction with floods: seminarstowards resilient deltas Dissemination
Flood Risk Assessment and Adaptation Approaches• Qualitative vs Quantitative assessment• Resilience (Socio-technical) approach vs robust engineering approach for Flood Risk Mitigation and Management• Different Approaches: Adaptive Policy Making (APM), Adaptation Tipping Point (ATP), Real-In-Options (RIO), and Adaptation Tipping Point - Adaptation Mainstreaming Opportunity (ATP-AMO) Top-down ATP’s in water management Risk Management Static are the specific boundary APM conditions where technical, economic, spatial or societal acceptable limits are ATP, Exploratory RIO Modelling Adaptation exceeded. Caused- Adap tation Effect-based/ Policy based/impact Decision Analysis Adaptation Pathways vulnerability Pathways ATP-AMO Dynamic Bottom-up
Gaps in the State of the Art• Uncertainty in urban growth scenario (Planned and unplanned)• Uncertainty in climate change / flood predictions• Lack of adequate/accurate data• Constraints for adaption (financial constraint, large-scale in-migration, gap in technical knowhow)
Objectives to identify the impacts of changing climate and urbanization on urban flooding and to assess the effectiveness of management, including flood mitigation and adaptation. The specific objectives are:I. Tailor the adaptation tipping point (ATP) method to a constrained context such as experienced in developing countries.II. Extend the traditional application of the ATP method through the incorporation of multiple drivers, namely climate change and urban growth.III. Demonstrate the extended ATP method for the current flood risk management (FRM) strategy for Dhaka.IV. Develop alternative FRM strategies including multi-layer safety for Dhaka by taking a combined top-down/bottom-up approach, and assess these strategies with the extended ATP method.V. Compare the effectiveness of multi-layer safety for adapting to increasing flood risks between Bangladesh and the Netherlands.
Research questionsI. How can the ATP method be adapted to a developing country context, in which management objectives may be lacking, not well defined or exceeded?II. How can the spatio-temporal dynamics of (planned and unplanned) urban growth be incorporated into the ATP method?III. What are the (intermediate) goals, measures and critical ATPs of the current FRM strategy of Dhaka?IV. Which alternative FRM strategies can be identified for Dhaka, and are these strategies effective in postponing the critical ATPs?V. Is multi-layer safety an effective way to adapt to changes in flood risk in urbanised delta areas?
Dhaka City-The Case Study• Area of DMA is 360 sq.km and DAP area is 1528 sq.km (590 sq mile)• Population of Dhaka city: 12 million Turag river (2010)• DWASA: key agency for water supply Tongi Canal system, sewerage and drainage (since 1963) Balu• Present water demand: 2200 MLD River• Water demand: 91% demand is met up by 4 SWTPs and 575 DTWs• Source of water: 87% water from DTWs Lakhya River Five rivers: Turag, Buriganga, Dhaleshwari, Lakhya, Balu and Tongi canal Buriganga Ground water: Relatively low depth of River aquifer Rainfal: 2400 mm average annual rainfall Dhaleswari (between 2001-2008, NWRD) River
Dordrecht-The Case Study• in the delta of the rivers Rhine and Maas and is situated in the transition area between rivers and sea.• 118 thousand inhabitants with a population of 1500 inhabitants per km2• 99 km2 of which 19 km2 consists of surface water.
Change in Builtup area (1993-2007) Change in Vegetation area (1993-2007) 23% to 47% 58% to 40%
Flood map of 1988 Flood map of 1998•75% area of western part inundated •23% area of western part inundated•Duration of 3 weeks •61 wards were affected•Flood height higher than 1998 (3-4.5m) •Duration was 2 months•2.5 million people affected Data Source: IWM
Flood map of July-Aug 2004 Flood map of September 2004 •600 mm rainfall from 11-15th Sept•Inundated Area 40% •Average 297 mm •341 mm rainfall on 13th Sept
Flood map of August 2007 Flood Map of July 2009• Above average year flooding• Less severe than 2004, 1998 or 1988 • Highest rainfall of 333 mm in 24 hrs• Record number of patients with diarrhoea (21,401 in between 27th-28th July. August), dehydration and cholera. (Source: ICDDRB) • 1 day maximum rainfall of 448mm
Dhaka City Flood Management Systems Flood Infrastructure Western Part (136 sq km) • Fully flood protected • Inundation occurs due to intensive rainfall • Inadequate drainage systems Eastern Part (124 sq km) • No flood protection • Encroachment of water bodies • Lack of coordination between agencies
DHAKA: LOCATED IN THE DELTA FORMED BY GANGES - BRAHMAPUTRA/JAMUNA -MEGHNA SYSTEMS
Deviation of Rainfall from daily normal (1961-1990) 40 120 100 30 80 Rainfall deviation (mm)Rainfall deviation (mm) 20 60 10 Hydrographs of Buriganga at Dhaka 40 0 (1988-2009) 20 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep 29-Sep 0 -10 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep 29-Sep -20 -20 -40 Dates Dates Fig. 6: Temporeal variation of the deviation of daily rainfall during July-September 1988 Fig. 7: Temporeal variation of the deviation of daily rainfall during July-September 1998 from the daily normal of 1961-1990 from the daily normal of 1961-1990 400 350 300 Rainfall deviation (mm) 250 200 150 100 50 0 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep 29-Sep -50 Dates Fig. 8: Temporeal variation of the deviation of daily rainfall during July-September 2004 from the daily normal of 1961-1990
Review of Planning InitiativesDacca Master Plan, 1958, DIT Basically a land use plan prepared for 20yr period.Dhaka Metropolitan Development Plan (DMDP) 1995, by RAJUK (MOHPW) DMDP includes: a) Structure Plan (SP) 1995-2015 b) Urban Area Plan (UAP)/Master Plan (1995-2005) c) Detailed Area Plan (DAP) SP provides long term strategy for growth, spatial and sectoral policies UAP, a mid term plan, includes Resource maps, Interim management report & Multi sectoral investment program DAP provides detailed planning for specific sub areas.Detail Area Plan (DAP) Approved by cabinet on 21st June, 2010 Includes 3.4 lakh acres (excluding restricted areas) Provides detailed planning proposals for specific sub-areas of Dhaka Objective is to prevent flooding & ease the traffic congestion
Review of Planning InitiativesFlood Action Plan (FAP 8A and FAP 8B) Prepared in 1988 for flood protection and drainage of the Greater Dhaka City FAP-8A comprises the East area (124 km2) of Dhaka city and FAP-8B comprises of West area (136 km2) of Dhaka city. FAP-8B program proposes construction of drainage facilities along with Natural drainage khals/canals, Natural storage and reservoirs of storm waterBANGLADESH CLIMATE CHANGE STRATEGY & ACTION PLAN 2009 Adapt of climate change threats Contains two parts First part based on physical and climatic contexts, core socio-economic realities and policies in the country and the consequent rationale for a strategy on climate change Second part proposes interventions on six thematic areas: i) Food Security, Social Protection & Health, ii) Comprehensive DM, iii) Infrastructure, iv) Research & Knowledge Management, v) Mitigation & Low Carbon Dev., vi) Capacity Building & Institutional Strengthening
Some Ongoing Projects DWASA projects, funded by JICA, include khal improvement, main drains, construction of culvert and dredging. Badda urgent project to remove water logging (DWASA) Dholai Khal Rehabilitation and area development (DCC/World Bank) Detail design of FAP 8B, funded by ADB which includes strengthening of the western embankment with pumps and sluice gates. Bangladesh Delta Plan Preparatory phase CORFU project
Future Planning Initiatives Bangladesh Delta Plan draws experience from the "Netherlands Delta Plan 2100“ will be incorporated in the sector plans will be implemented through dev. programmes of GOs and NGOs appropriate institutional arrangement funding source from govt. revenue and development budget and development partners a holistic long term (50 to 100 years) integrated strategy plan for Bangladesh to achieve long term sustainable development through adaptive water governance
Proposed Methodology for the study Input Process Output Landuse Urban Urban Demography Growth Modelling Growth Scenarios DEM Rainfall Flood Flood River Water level Risk Modelling Scenarios Climate change scenarios Urban Drainage System Urban Development Adaptation Adaptation Policies & Plans Assessment Tipping Points Climate Change Policy and Action Plan Flood Risk Management & Adaptation Strategies
Urban growth scenarios
Flooding under different UG scenarios
Conclusion/Concerns Dhaka is in its incumbent stage of implementation of the DAP Urban growth’s threshold value have to identified and taken into consideration at planning/policy level Climate change effects needs to be specific and concise to be able to help set the standards for decision making Adaptation tipping points and turning points needs to be identified Adaptive delta management approach in perspective of changing urban and climate environment needs to be examined Flood management with inclusion of flexible and rigid strategies need to be compared to find the best combination