Project teams using this tool assess the potential impact of climate and geophysical hazards on the physical components of their project. This potential impact is the combination of the exposure and sensitivity of the project’s physical assets, natural resources, and systems. Ratings of potential impact rely on the user’s subject matter expertise and contextual understanding.
The nature of physical investments and associated potential impacts vary significantly from one subsector to another. Therefore, the tool allows users to identify their water projects’ emphasis according to six subsectors, which align closely to the World Bank internal coding systems:
- Land Use & Watershed Management
- Dams & Reservoirs
- Water Supply
- Wastewater
- Sanitation, and
- Riverine Flood Protection
This organization allows the user to capture the particular sensitivities within each subsector. In addition, the assessment results can be displayed by subsector, enabling users to identify which specific elements of their project could potentially be impacted.
Figure 3. Examples of current vulnerabilities of freshwater resources and their management; water stress map in the background.1
Project design and vulnerability: A water project’s design and implementation will influence its vulnerability to climate and geophysical hazards. The interrelationship between climate and water-related projects, as well as the long life span of these projects, support the need for addressing climate impacts in designing projects related to land use/watershed management, dams and reservoirs, water supply, waste water, sanitation, and riverine flood protection.
Evaluating historical and future trends: Potential impacts are evaluated separately for the Historical/Current and Future time-frames because the level of potential impact may change as exposure changes over time. It is important to first evaluate historical trends and current baselines to understand the conditions and trends under which water systems are currently operating.
For example, recent trends for a region might indicate that the dry season is becoming drier and longer, increasing the potential impact on available water supply. In such a case, by applying the projections for future climate in that location and relating them to the relevant time scale (see Figure 2), users can focus on the aspects of their project that will be relevant to the outcome of the project in the Future time frame.
For investments with long lifetimes, such as physical infrastructure, considering future conditions is critical to avoid “locking in” designs that are not suited for higher sea levels or warmer temperatures. For example, levees designed to address historical river flows may become less effective in the future if flow volumes significantly increase. Similarly, water or waste water treatment facilities only designed to meet historical patterns may suffer serious damage if storm surges become more frequent or more severe.
Rating potential impact: The potential impact assessment is rated against multiple hazards, drawing on all of the exposure information and the expert judgment of the user. The tool displays all of the hazards in order to provide a more integrated picture of climate in the project location and better assess how it may affect the project.
For example, water supply may be reduced by a number of different hazards, including drought, extreme temperature, and strong winds. In isolation, any one of these hazards might have a small effect on water quantity, but in combination their impact could be significantly worse. By viewing all of these hazards together, the user can identify their potential interactions and rate impact accordingly. Alternatively, in some cases, the user may be able to quickly identify the key hazards that drive potential impact and prioritize those in selecting a rating.
Rating scale: The rating scale for potential impact is:
| Insufficient Understanding | No Potential Impact | Low Potential Impact | Moderate Potential Impact | High Potential Impact |
In selecting these ratings, users overlay sensitivity considerations with the previous exposure ratings to assess potential impact. Therefore, the potential impact ratings may or may not align with the exposure ratings.
For example, suppose a waste water treatment plant is highly exposed to sea level rise and storm surge. If it is surrounded by a protective levee and key assets are elevated, then the potential impact will be lower than if it is not so protected.
See the Resource Annex for a list of additional resources on the potential impacts to climate change for the water sector.
1 B. C. Bates, Z.W. Kundzewicz, S. Wu, and J.P. Palutikof, editors, “Climate Change and Water,” Technical Paper of the Intergovernmental Panel on Climate Change (Geneva:IPCC Secretariat, 2008).