Strengthening the Resilience of the Water Sector in Khulna to Climate Change (Financed by the Climate Change Fund)
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Technical Assistance Consultant’s Report Project Number: 42469-01 August 2010 Bangladesh: Strengthening the Resilience of the Water Sector in Khulna to Climate Change (Financed by the Climate Change Fund) Prepared by Institute of Water Modelling Dhaka, Bangladesh Alterra Netherlands For Local Government Division Khulna City Corporation Khulna Water Supply and Sewerage Authority This consultant’s report does not necessarily reflect the views of ADB or the Government concerned, and ADB and the Government cannot be held liable for its contents. GOVERNMENT OF THE PEOPLE’S REPUBLIC OF BANGLADESH MINISTRY OF LOCAL GOVERNMENT, RURAL DEVELOPMENT & COOPERATIVES LOCAL GOVERNMENT DIVISION The Asian Development Bank (ADB) ADB TA-7197 BAN: Strengthening the Resilience of the Water Sector in Khulna to Climate Change Food Water Environmen tal Waste HUMAN Climatic HEALTH Social Agricultural Infra structure Final Report August 2010 ADB TA-7197 BAN: Strengthening the Resilience of the Water Sector in Khulna to climate change Final Report EXECUTIVE SUMMARY 1. With vast low lying areas, Bangladesh is considered as one of the most vulnerable countries in the world to climate change. Strengthening the resilience to climate change is pivotal in all its development and poverty alleviation activities. The city of Khulna, being located in the coastal area of Bangladesh, and influenced by tides from the Bay of Bengal, is highly vulnerable to climate change. The increasing salinity intrusion into the city waters and the anticipated sea level rise might have a major impact on the water resources and the water and drainage infrastructure of the city and its surrounding areas. The city experiences frequent water logging during the rainy season. The possible increase in precipitation due to climate change coupled with sea level rise will make the situation even worse. 2. During the fact-finding mission to Bangladesh in September 2008, an ADB Mission discussed with the Government the possibilities of impacts of climate change on two planned water sector investment projects in Khulna, namely the City Region Development Project and the Khulna Water Supply Project. ADB suggested assessing the impacts of climate change and identifying adaptation options before the investment projects are implemented. So this study project titled „Strengthening the Resilience of the Water Sector in Khulna to Climate Change‟ was conceived after subsequent agreement between the Govt of Bangladesh and ADB in October 2008. 3. The overall objective of the project is to assess the impacts of climate change on drainage, water availability, and the salinity situation in Khulna City and to make recommendations to make the system more resilient to climate change. The study will prepare a list of adaptation options including both structural and non-structural for two planned investment projects: the City Region Development Project and the Khulna Water Supply Project. The output of the TA project will be reflected in the design of these future projects and other Govt interventions. The overall objective would be fulfilled by accomplishing the following specific objectives: i) identification of impacts of climate change on flooding, drainage, salinity and water availability aspects; ii) providing adaptation options based on social, economic, public health and urban planning aspects; iii) conducting workshops and trainings to develop capacity of relevant stakeholders/agencies to combat the impacts of climate change scenarios. 4. The study area comprises the area under the Khulna City Corporation (KCC), which is about 45 km2. The project activities were divided in three main components: socio- economic analysis, climate scenarios, and mathematical modelling. Socio-economic, health issues and urban planning were carried out for scenario development and to assess the impacts of climate change and adaptation measures. The climate analysis was carried out to develop climate scenarios for the region. In order to assess the impact of climate change on the water sector of Khulna, several mathematical models were used. The South West Region Model (SWRM) and the SWR-Salinity model can simulate the hydrodynamics and salinity conditions of the rivers at various locations including the proposed water supply intake locations. The Khulna Urban Drainage (KUD) model is a new model especially developed for this project. This model is able to show the water logging conditions of Khulna City. All these models can take into account the impacts of climate change and translate those impacts on the water sector of Khulna city. Impacts of various physical interventions on the water sector can also be simulated by these models. i ADB TA-7197 BAN: Strengthening the Resilience of the Water Sector in Khulna to climate change Final Report 5. The works started with the collection and review of available data and information. To feed the models and subsequent analyses, additional data and information collection activities were carried out. Topographic and hydrometric data (water levels, flow discharges, salinity) were collected and socio-economic data were gathered through household, urban planning and public health surveys. Maps were collected from KCC and KDA and satellite images were procured to update the land use pattern and also to update the project base map. 6. Past published evidence and experience predicts that due to its sectoral impact, the climate change is likely to have negative impact on the overall public health situation of Khulna if not addressed efficiently. The information generated from the socio- economic survey (January-February 2010), along with FGDs (Focal Group Discussions), KIIs (Key Informant Interviews) and the health situation reports on Flood 2007, Cyclone Sidr (2008) and Cyclone Aila (2009) – complements these findings and gives an impression of increasing threat of the vulnerable population of Khulna to hot spells, flooding, water logging and salinity and scarcity of safe water. 7. Urban planning is a key issue in terms of land-use plans and policies and current and future practices for coping with the climate viability and extreme weather events. Primary and secondary data have been used to assess the current development pattern of the area and future trends of expansion. To derive the urban development scenarios of Khulna city, satellite images and land-use maps were used, a physical infrastructure survey in the hotspot (regularly water logged) areas was conducted and the Master Plan for Khulna was consulted. These data and analyses helped to chalk out a scene of the transformation taking place in Khulna. This nature of transformation in the land use of the city supports the current philosophy in urban planning practice. This consists of places of mixed use zones guided and controlled by a set of precise planning regulations, which is a shift from the old land use zoning practice. Ultimately, there will be very few exclusive zones. Some solely residential areas will perhaps remain intact because of the resistance created by their social status. Apart from that, some other significant uses like industrial, green space, administrative and community services will keep their places. Other parts of the city will mostly be mixed used. 8. Integrated scenarios were developed for socio-economic change and climate for the years 2030 and 2050. To account for the uncertainties involved three integrated scenarios were developed: a trend scenario (called the realistic scenario, assuming business-as-usual), an optimistic scenario and a pessimistic scenario. With the help of the modelling framework and using the trend scenario, various adaptation options were studied and the impacts of the options on evaluation criteria were analysed. The adaptation strategies developed for this study were discussed with the stakeholders to receive feedback and to assess the level of public acceptance. The robustness of the recommended adaptation strategies were assessed by testing them for the optimistic and pessimistic scenarios. 9. Twelve indicators were considered for the socio-economic scenarios. These are: KCC population, GDP growth rate, water demand, pattern of residential building, water supply connections, economic and social enterprises, proportion contribution of GDP of Khulna, paved road, diarrhoea incidence during disasters, urban development patterns, and proportion of urban poor people below upper and lower poverty lines. Trends in these variables were analyzed to develop „without‟ project scenarios in 2030 and in 2050. ii ADB TA-7197 BAN: Strengthening the Resilience of the Water Sector in Khulna to climate change Final Report 10. Two climate change scenarios based on the IPCC approach were used. These are: „A2‟ which describes the business-as-usual situation, i.e. continuing with high emissions, and „B1‟ which assumes a more sustainable future. Analyses of the climate change scenarios show an increase of extreme rainfall events in the A2 scenario by 2050. There is not a large difference in the frequency of extreme rainfall event between the historic period (2003-2008) and 2020-2040. However, the changes in extreme rainfall events are considerably higher during the 2041-2060 period. The occurrence of a rainfall event of more than 50 mm in 6 hours at Khulna is almost 6 times a year in 2041-2060 compared to just over 4 times a year for the historic period (2003-08). It is even worse for an event of more than 150 mm in 6 hours. The chance that this will happen at Khulna changes from 0% (no occurrence in the control period 2003-2008) to 24% (once in every four years). 11. One of the most important impacts of climate change for low lying countries such as Bangladesh is sea level rise (SLR). Given the high uncertainty in SLR predictions, it is difficult to define the most likely scenario for 2030 and 2050. Therefore two “plausible” future sea level rise scenarios were chosen. With the available knowledge, the two selected scenarios are at the lower and at the higher ends of the spectrum. For 2030, a plausible low scenario of 10 cm was selected and a plausible high scenarios of 25 cm.