Animesh K. Gain

Assessment of Future Water Scarcity at Different Spatial and Temporal Scales of the Brahmaputra River Basin

Climate change is one of the main driving forces that affect both the temporal and spatial variability of water availability. Besides climatic change, current demographic trends, economic development and related land use changes have direct impact on increasing demand for freshwater resources. Taken together, the net effect of these supply and demand changes has led to a growing water scarcity in major international river basins. The Brahmaputra River Basin is one of the most vulnerable areas in the world, as it is subject to combined effect of climate change and development pressures. A robust assessment of water scarcity considering both climatic and socio-economic changes is therefore vital for policy makers of the basin. In this study, we analyze future water scarcity of the Brahmaputra Basin in a geographically and temporally detailed manner, incorporating several novel approaches: (i) the application of consistent set of scenarios to estimate future water scarcity; (ii) estimation of water demand in terms of both water withdrawals and consumptive water use; (iii) comparison of water demand and availability on different temporal scales i.e., yearly, seasonal and monthly rather than only annual basis. (iv) assessment of groundwater recharge affected by climate change together with future demands for groundwater abstraction. Although the Brahmaputra Basin is one of the water abundant regions of the world, our analysis illustrates that during dry season water scarcity for the Basin will become more severe in the coming decades, which requires special attention to the decision makers of the authority.

Evaluating IWRM implementation success: are water policies in Bangladesh enhancing adaptive capacity to climate change impacts?

Optimizing the capacity to adapt to climate change impacts has become a critical challenge for human societies. This article therefore evaluates how integrated water resource management (IWRM) approaches help enhance adaptive capacity to climate change impacts on water resources. An evaluative framework is derived from key IWRM principles and their roles in modulating adaptive capacity. This framework is then used to evaluate IWRM implementation in Bangladesh. The analysis draws on policy documents, interviews and a survey of policy makers. Results suggest that policy principles and implementation in favour of IWRM can be a source of success but also of failure for adaptive capacity. Recommendations for amending the concept with the aim of increasing adaptive capacity are outlined.

Adaptation to flood risk - results of international paired flood event studies

As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro-climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur.

Thresholds of hydrologic flow regime of a river and investigation of climate change impact—the case of the Lower Brahmaputra river Basin

The sustainability of social-ecological systems depends on river flows being maintained within a range to which those systems are adapted. In order to determine the extent of this natural range of variation, we assess ecological flow thresholds and the occurrence of potentially damaging flood events to society in the context of the Lower Brahmaputra river basin. The ecological flow threshold was calculated using twenty-two ‘Range of Variability (RVA)’ parameters, considering the range between ± 1 standard deviation from the mean of the natural flow. Damaging flood events were calculated using flood frequency analysis of Annual Maxima series and using the flood classification of Bangladesh. The climate change impacts on future river flow were calculated by using a weighted ensemble analysis of twelve global circulation models (GCMs) outputs driving a large-scale hydrologic model. The simulated climate change induced altered flow regime of the Lower Brahmaputra River Basin was then investigated and compared with the calculated threshold flows. The results demonstrate that various parameters including the monthly mean of low flow (January, February and March) and high flow (June, July and August) periods, the 7-day average minimum flow, and the yearly maximum flow will exceed the threshold conditions by 1956–1995 under the business-as-usual A1B and A2 future scenarios. The results have a number of policy level implications for government agencies of the Lower Brahmaputra River Basin, specifically for Bangladesh. The calculated thresholds may be used as a good basis for negotiations with other riparian countries of the basin. The methodological approach presented in this study can be applied to other river basins and provide a useful basis for transboundary water resources management.

An integrated approach of flood risk assessment in the eastern part of Dhaka City

Abstract The flood risk is a function of the flood hazard, the exposed values, and their vulnerability. In addition to extreme hydrological events, different anthropogenic activities such as extensive urbanization and land use play an important role in producing catastrophic floods. Considerations of both physical and social dimensions are therefore equally important in flood risk assessment. However, very often the risk assessment studies focus either on physical or social dimensions. In addition, the available studies often focus on economic valuation of only direct tangible costs. In this study, we provide an integrated flood risk assessment approach that goes beyond the valuation of direct tangible costs, through incorporating physical dimensions in hazard and exposure and social dimensions in vulnerability. The method has been implemented in the Dhaka City, Bangladesh, an area internationally recognized as hot spot for flood risk. In this study, flood hazards for different return periods are calculated in spatial environment using a hydrologic model, HEC-RAS. Vulnerability is assessed through aggregation of various social dimensions, i.e., coping and adaptive capacities, and susceptibility. We assess vulnerability for both baseline and improved scenarios. In the baseline scenario, current early warning for study area is considered. In the alternative scenario, the warning system is expected to improve. Aggregating hazard, exposure and vulnerability, risk maps (in terms of both tangible and intangible costs) of several return period floods are produced for both baseline and improved scenarios. Compared to traditional assessments, the integrated assessment approach used in this study generates more information about the flood risk. Consequently, the results are useful in evaluating policy alternatives and minimizing property loss in the study area.

Integrated Risk Assessment of Water-Related Disasters

Abstract This chapter presents a conceptual framework (KULTURisk Framework or KR-FWK) and its implementation methods (SERRA or Socio-Economic Regional Risk Assessment) for integrated (physical and economical) risk assessment and evaluation of risk prevention benefits in the field of water-related processes. The KR-FWK (i.e. from the name of the European project within which it originated) and the SERRA approach were developed upon preexisting proposals, with three main innovation aims: (1) to include the social capacities of reducing vulnerability and risk, (2) to provide an operational solution to assess risks, impacts, and the benefits of plausible risk reduction measures, by including a monetary estimation of costs and benefits, and (3) to go beyond the estimation of direct tangible costs. Vulnerability is considered as a result of the interactions between physical (territorial) characteristics and the susceptibility and the capacities of the socioeconomic system to adapt and cope with a specific hazard, expressed as a nondimensional index ranging between 0 and 1. Exposure, is instead assessed in monetary terms, and thus the multiplicative combination of two indices ranging between 0 and 1 (hazard and vulnerability) with a third one (exposure) expressed in monetary terms produces a monetary quantification of risk, which can be used for supporting decisions via cost-benefit analysis. Regarding the third aim of going beyond the estimation of direct tangible damages, operational solutions are proposed to evaluate four possible socioeconomic costs possibly deriving from the adverse consequences of flood, namely direct/indirect and tangible/intangible costs. The proposed methodology aims to be comprehensive with respect to the set of receptors usually considered in the literature of regional risk assessment. The sets of receptors considered are people, economic activities, categorized as (1) buildings; (2) infrastructures; and (3) agriculture and cultural heritage and ecosystems. We show how to apply SERRA and the KR-FWK in the case of Dhaka/Lower Brahmaputra/Bangladesh, by reusing elaborations already done or in progress and by developing some minimal new work; e.g. to demonstrate indirect/intangible costs.

Integrated spatial assessment of the water, energy and food dimensions of the Sustainable Development Goals

Water is considered the bloodstream of the biosphere, but its management is one of the most important challenges for human development. In view of the sustainable water management, several approaches have been proposed: Integrated Water Resources Management, Adaptive Management and, more recently, Water–Energy–Food (WEF) Nexus. Considering these approaches, over the last few decades, extensive efforts have been made to develop assessment methods and tools framed within the paradigm of sustainable development. As part of a holistic assessment of water resources, the recent approach based upon the WEF Nexus narrows down the consideration of intersectoral linkages to three dimensions that are of prominent interest, in particular in developing countries. This study presents a comprehensive indicator-based approach for the assessment of water, energy and food securities, with reference to the Sustainable Development Goals of the United Nations. The main ambition of the proposed approach is to provide a tool to monitor progresses, compare different geographical areas, highlight synergies and conflicts amongst and within the three dimensions of the WEF Nexus, and provide support for improved—more effective—management strategies to meet the goals. The proposed approach is demonstrated in the Ganges–Brahmaputra–Meghna (GBM) River Basin in Asia and to the Po River Basin in Europe. The comparative analysis suggests that WEF security is currently rather low in the GBM basin compared to the other case study and other parts of the world and allows the identification of which dimensions (indicators) require special attention on the part of local and global policy makers.

Challenges in operationalizing the water–energy–food nexus

ABSTRACT Concerns about the water–energy–food (WEF) nexus have motivated many discussions regarding new approaches for managing water, energy and food resources. Despite the progress in recent years, there remain many challenges in scientific research on the WEF nexus, while implementation as a management tool is just beginning. The scientific challenges are primarily related to data, information and knowledge gaps in our understanding of the WEF inter-linkages. Our ability to untangle the WEF nexus is also limited by the lack of systematic tools that could address all the trade-offs involved in the nexus. Future research needs to strengthen the pool of information. It is also important to develop integrated software platforms and tools for systematic analysis of the WEF nexus. The experience made in integrated water resources management in the hydrological community, especially in the framework of Panta Rhei, is particularly well suited to take a lead in these advances.

A Conceptual Framework for Comprehensive Assessment of Risk Prevention Measures: The Kulturisk Framework (KR-FWK)

A conceptual framework integrating different disciplines is described in order to provide the basis for the development of a methodology to comprehensively evaluate the benefits of risk prevention. Two main innovations are proposed with regards to the state of the art: to define a measure of risk that goes beyond the direct tangible costs and to include the social capacities of reducing risk.

Social, hydro-ecological and climatic change in the southwest coastal region of Bangladesh

This study investigates the historical development of the southwest coastal region of Bangladesh through the lens of human-delta co-evolutionary system. The change process of social and hydro-ecological systems is described based on the drivers–pressure–state–impact–response (DPSIR) framework. The multiple physical and socio-economic drivers such as climatic change, upstream development, geologic process, land use change-affected river flow, salinity, water logging and cyclones are creating adverse impacts on ecology (e.g. mangrove forest) and society (e.g. population migration). Existing management practices such as the Coastal Embankment project (CEP) also created adverse impacts on social–ecological system. In addition to the geology of this region that plays the major role in the delta development process, human interventions such as large coastal development projects have intervened the land formation processes. The trends and impacts of these changes along the coast unfold the necessity of integrated management approach such as Integrated Water Resources Management (IWRM) and Integrated Coastal Zone Management (ICZM). Comprehensive understanding of social and hydro-ecological system in southwest coastal region through DPSIR approach presented in this study can provide effective solution for implementing ongoing management strategies.