In order to ensure a reliable assessment of drought vulnerability in the DEWFORA case studies, a white paper was prepared for discussing the methodology for defining it. The obtained drought vulnerability results were then incorporated into an early warning protocol for
natural disaster management. The proposed methodology involved four consecutive steps:
1) Defining drought hazards, which are natural symptoms that can be used for diagnosing or predicting droughts. Hazard indicators are numerical values that provide information about droughts (when it starts and ends, where it takes place). They can be used to compare drought impacts over different spatial and temporal periods. Typical drought hazard indicators are Precipitation Deciles, Standardized Precipitation Index (SPI) and Surface Water Supply Index (SWSI).
2) Defining drought impacts in several fields, for example:
- Agriculture: crop models provide information about existing systems in a zone, their variables (crop yield, water demand) and how these parameters change when droughts take place.
- Water supply systems: indicators are expressed as a probability of supply deficit. This probability can vary depending on demand characteristics, available water resources and existing infrastructures.
3) Defining the drought exposure, that is, the number of people affected. The sources of data vary in each case study.
4) Defining the adaptive capacity of the zone, which is the ability of a community to predict, prevent and recover from droughts. It can be obtained from four different factor groups:
- Social capacity, which depends on strategic planning and adopted policies. Suitable indicators are: agricultural employment, literacy rate, life expectancy or access to sanitized water.
- Economic capacity: Gross Domestic Product (GDP) is the most accepted indicator of economic capacity. In general terms, the higher the GDP is, the higher is the adaptive capacity.
- Technological eco-efficiency: GDP per unit energy use, high technology exports and CO2 emission per capita are suitable indicators.
- Natural capital: this factor group is related to water availability, and can depend on natural (existing water basins), infrastructural (water storage and transport structures) or policy (water management regulations) parameters.
After defining all these parameters, different regions can compare hazards, impacts and exposures against adaptive capacities. Different thresholds, which are specific indicator values that define when an action must be initiated, can be established regarding specific boundary zones in the resulting “vulnerability map”. The proposed approach is very advantageous from the operation point of view, since it relates the hazards with their effects at different levels (i.e. social, economic, and environmental). Moreover, applying vulnerability indicators to the project’s early warning system can be interesting in order to evaluate the capacity to anticipate and fight against the adverse effects of droughts.
Improved Drought Early Warning Forecasting for Strengthen preparedness and adaptation in Africa. Deliverable 3.1. White paper for definition of drought vulnerability across Africa