The Delta Dynamic Integrated Emulator Model (ΔDIEM)
Achieving populous Deltas development goals by 2100 is a complicated and complex problem. ΔDIEM is a modelling tool to aid poverty alleviation planning in Coastal Bangladesh. The model scope is to test plausible future scenarios and quantify interdependencies of
- the bio-physical environment and ecosystem services,
- rural livelihoods, poverty & health
- associated governance
The model operates at the Unions level on a daily time step. Unions are the smallest rural administrative and local government units in Bangladesh. There are 4550 Unions in Bangladesh from which a subset of 653 Unions are simulated by ΔDIEM. These 653 unions are in the agricultural dominated South-West coastal zone. A daily time step is required to resolve the soil water and salt balance dynamic due to environmental drivers (e.g. rainfall, flooding, and evapotranspiration) and human activities (agriculture, aquaculture).
The model is being developed in a genuine participatory approach that includes five main groups of participants. At the very beginning, a broad set of stakeholders (more than 50 agencies) provided the narratives of three plausible future scenarios (termed Business as Usual, More Sustainable and Less Sustainable) that would like to explore. A comprehensive seasonal survey of more than 1500 households provide the ground knowledge about interdependencies between different archetypes of households and ecosystem services. An ESPA Deltas team of more than 100 specialist and students provided detailed assessment of future trends and changes of the natural and socio-economic systems. The quantitative sectorial assessment provided by the ESPA Deltas team has been then integrated into the ΔDIEM that allows users to explore a broad range of interventions under the three different scenarios.
ΔDIEM will be freely available via an open source licence after the project concludes. If interested please contact Prof. Munsur Rahman (firstname.lastname@example.org) at BUET.
ESPA Deltas has developed a novel policy-driven, integrated framework that describes the linkages and drivers between the environment, ecosystem services, poverty, health and livelihoods in coastal Bangladesh (population of about 14 million people). This approach simulates livelihoods and poverty within the study region as driven by multiple environmental drivers operating at multiple scales (global down to the study region and smaller). The results are encapsulated in the Delta Dynamic Integrated Emulator Model (ΔDIEM) which quantitatively includes a large number of coupled components, including, uniquely, a livelihoods/wellbeing module describing the consequences of change for the rural poor of environmental drivers. The ΔDIEM model is specifically designed to facilitate the analysis of the complex impacts of environmental and societal change on poverty/well-being, providing annual results at the Union level (4-5 villages/union 627 unions in study region) to 2050. The impacts of environmental changes, natural hazards and climate change, and a wide set of policy interventions are considered in the broader the Ganges-Brahmaputra catchment, the Bay of Bengal Bangladesh and within the study area and assessed in terms of poverty and other socio-economic outcomes within the study area. These outcomes are linked to Government of Bangladesh priorities and development trajectories until 2050 (and longer as required).
The ΔDIEM model is unique in its capacity to link bio-physical, socio-economic and governance processes. So for example, starting with a number of scenarios of climate change over the next 30 years, the model might provide a range of plausible impacts of river and tidal inundation on salinity and the consequent impacts on agriculture and aquaculture and ultimately poverty, health and livelihood. This is achieved through the system-based structure of the model which uses highly innovative approaches to link environmental and social information. To this end, ΔDIEM is currently being used to test several real world potential interventions identified by government agencies, including the building of the Ganges Barrage, at the request of the General Economic Division (GED) of the Bangladesh Government. In this case, the future will be simulated at an annual time step with and without the barrage combined under a range of plausible scenarios (e.g. climate, hydrology, population, etc.) providing the environmental and social consequences. These results will inform the developing Bangladesh Delta Plan 2100 (BDP2100) which GED are leading.
Substantial and ongoing stakeholder engagement is integral to the whole process of ΔDIEM development and includes input from 57 institutions and organisations including, Ministry of Planning, Ministry of Water resources. Stakeholders have input on: i) issue identification; ii) national scenario development; iii) verification of results and processes; and iv) formulation and testing of policy options. To further understand and represent communities and their livelihoods, extensive multi-season qualitative and quantitative household surveys were conducted (1400 households repeated over 3 seasons) which provided ΔDIEM with detailed information on the utilisation of ecosystem services by sectors of different socio-ecological communities. This approach has a particular focus on the poor and is supported by a statistical demographic analysis between census-based poverty indicators and socio-environmental variables including salinity, waterlogging and road access. The results of this combined work have been integrated into the households and livelihoods module of ΔDIEM. They highlight the complex relationship between the environment, income and migration.
The design and development of ΔDIEM is driven by the planning needs of the Bangladesh government in the prosecution of mid to long term policy strategies. This included an analysis of stakeholder needs and an extensive review of the available policy documentation across a number of ministries and decision making bodies. The intention is to provide a platform where decision makers can explore the robustness of rafts of policy against a range of climatic and socio-environmental futures and assess the adaptability and robustness of policy in diverse futures.
The table below lists the key ΔDIEM outputs that have been identified as relevant to the future socio-economic state of coastal Bangladesh. Important sources include the BDP2100 and the associated Bangladesh government’s 7th Five-Year Plan for 2016-2020 and 6th update of the Poverty Reduction Strategy Paper which identifies the role of the BDP2100 in reducing issues of livelihood loss and poverty. This process included developing a strong relationship with the General Economic Division of the Ministry of Planning. GED have been particularly active in coalescing the requirements of a number of ministries and agencies and providing ΔDIEM with specific information demands which are expressed in the outputs below.
Key Output Parameters from ΔDIEM
River water elevation (m)/ inundated area (ha)/ mean inundation depth (m)
River salinity (ppt)
groundwater salinity (ppt)
soil salinity (ds/m)
Crop productivity (kg/ha)
Fish catches (tons)
value of catches (BDT) Income
Net earnings from farming (BDT)
Total farm labourers
Local farm labour force
Seasonal migrants doing farm labour
Wellbeing / Poverty / Health
Asset-based poverty indicator (census based)
Relative wealth indicator (process-based)
Household incomes (BDT/month)/ farming, fishing, farm labour, forest collection, business, manufacturing, farm animals, remittances
Household costs/expenses (BDT/month)/ livelihood costs, food, essential house, non-essential house, sporadic house, education, health, other, loans
Household debt (BDT)/ Average household calorie (kcal/cap/day) & protein (g/cap/day) intake, $1.9 poverty headcount indicator, income and consumption-based Hunger period (number of months having less than 2132 kcal/cap/day)
Sectoral output (tons, BDT): agriculture, aquaculture, forest goods, manufacturing, businesses, off-shore fisheries, GINI coefficient/GDP/capita/
Total income tax revenue (BDT)/Mean household debt level (BDT)
Meeting a Need
During the development of ΔDIEM one of the key expressions of interest from GED has been the need to provide further specific poverty and socio-economic data to augment the processes underway in the development of the BDP2100. GED are interested in detailed outcome scenarios of the impacts of large scale interventions in the coastal zone which consider distributional effects as well as macro-economics. The status of the rural poor is not simply coupled to national growth. Increased land prices, for example as the result of building coastal defences, can mean the poorest being barred from accessing what were common rights and the development of industrialised agriculture can result in mass unemployment and disenfranchisement of the poor. As such ΔDIEM expressly considers the perspective of the poorest members of society and maps their progress and welfare through time as a consequence of interventions. To this end GED has asked the Dutch participants in the development of the BDP2100 to work with ESPA Deltas and utilise, at least in an abstract form, the emerging results from ΔDIEM. This is an ongoing process and contact has recently been established to consider how this might be accomplished given the substantial difference in scale and detail of the two approaches.
Applying ΔDIEM in Policy Analysis: The Start of a Process
The ΔDIEM model has been functionally complete for a relatively short time and the process of its application is ongoing. Early reviews by GED and others are very encouraging and the process of building capacity in Bangladesh for the use and further development of the model are now underway. The ESPA Deltas project is, however, drawing to a close. In consultation with GED a number of areas are identified where this work might be taken forward and applied to national policy:
i) Embedding ΔDIEM in national policy processes. ΔDIEM is informing the BDP2100 at the present time and provides a tool for changing the approach to policy analysis in Bangladesh. A series of demonstration projects of its application would facilitate application and take-up of the existing model.
ii) Extending the ΔDIEM spatial domain. ΔDIEM has been developed as a test case for southwest coastal Bangladesh, while the BDP2100 is national. ΔDIEM could be extended to other areas of Bangladesh including the BDP2100 hotspot areas – most easily to the rest of the coastal zone, and a national model is feasible given what we have learned to date.
iii) Extend the socio-economic dimensions of ΔDIEM. ESPA Deltas considers an extensive set of poverty outputs and a number of specific health outcomes: linking these directly to biophysical changes was a fundamental innovation. However, it would be beneficial if these were extended, such as to include the nutritional health implications of food access, availability and utility of the poorRelevant Graphics