Written by Marloes Mul, IWMI Senior Researcher Hydrology and Water Resources
Building water infrastructure such as dams contributes to economic development, food, and energy security depending on their objective. In developing countries it is often seen as the most cost effective way to increase electricity production and irrigated agriculture. However, reaching these national objectives can often come at a cost to nature and local livelihoods which depend on healthy ecosystems. Modified river flows change the timing, quantity and quality of water flowing downstream. Yet, these constantly changing river flows are essential for livelihoods dependent on flood recession farming, floodplain cattle grazing, and fish production.
Integrated Water Resource Management (IWRM) calls for balanced development. This is difficult when national food and energy priorities impact local livelihoods and ecosystem services. Is it right that local and invariably poor people have to pay the price for national economic development? The argument for hydropower for economic development is valid, but natural infrastructure and the local benefits they provide should not be neglected in development planning and climate change adaptation strategies.
Under the ‘WISE-UP to Climate’ project the assumption is that built infrastructure and its benefits are well documented and understood, whereas natural infrastructure is less well understood and the benefits are harder to quantify. Through work led by the International Water Management Institute (IWMI), WISE-UP aims to quantify the benefits from natural infrastructure in the Volta basin so that it can be considered within the same decision-making framework as built infrastructure.
The Volta River basin is shared between six countries in West Africa and crosses a wide range of eco-climatic zones, from dry Sahelian climate in the north to humid tropical climate in the South. The monsoon climate and the generally flat basin contributes to large scale seasonal flooding, providing water for flood recession farming and riparian fishing. IWMI’s work has focused on the proposed Pwalugu dam area in the North of Ghana, close to the Burkina Faso border. The proposed dam is a good example of built infrastructure conceived to contribute to Ghana’s economic and development needs through hydropower generation and to minimize destructive flooding. However, it will also have local impact on the natural infrastructure that supports rural livelihoods, and downstream river flows.
Different sets of ‘benefits’ were identified at two scales: (i) at the overall Volta basin scale and (ii) in three riparian communities downstream of the proposed Pwalugu dam site. We reviewed existing information, conducted participatory mapping, and used remote sensing and GIS tools.
At the basin level, the sources of these different benefits come from both natural (e.g. wetlands and floodplains) and built infrastructure (small to large reservoirs). Ecosystem services support hydropower production, irrigation, flood recession farming, riparian fishing and cultural values associated with the seasonal flooding. In the riparian communities, the benefits are mostly derived from the seasonal flooding from the White Volta. This flooding supports natural pond refilling and sediment movement into the floodplains to re-fertilize the soils. But it also adversely affects the yield of rain-fed crops grown in the floodplains, when floods arrive before harvesting.
What is clear, and no surprise, is that the riparian communities derive tangible livelihood benefits through activities such as flood recession farming, livestock watering and fishing.
1) Map of key benefitsin the Volta River Basin
2) Ecosystem services map in Northern Ghana
These findings were presented to the riparian communities who confirmed that the ecosystem services identified are accurately represented. The map provides a visual representation of the dependency of the community on the benefits from flooding and natural infrastructure. The maps proved to be an extremely useful instrument for sparking in-depth discussion and local-level planning.
To quantify the link between the different benefits and the flow regime of the river, a hydrological monitoring network was established. A number of instruments were installed to better understand the movement of water back and forth between the river and the floodplain, both above and below ground. This enabled the development of a computer model which can be used to determine how the flows of water, and hence the water related ecosystem services, might change as a consequence of either upstream dam development or changes in river flow due to climate change. In this way the water required to provide the local benefits can be determined and any trade-offs, in terms of water allocation, assessed.
3) Construction materials
4) ES mapping in Pwalugu
5) Community engagement on ecosystem services maps in Pwalugu
6) Instrumentation and data collection
Many of the local practices of these communities are put at risk by the construction of the multi-purpose Pwalugu dam. However, the dam also creates opportunities, as it is expected to improve water availability for irrigation during the dry season as well as provide jobs.
On the downside, by modifying the flow of the river, key ecosystem functions may be affected. For example, soil fertility may decline as the dam will minimize flooding downstream and trap sediment that would normally flow onto the floodplain. The impact on flood recession farming activities could be large, potentially impacting local crop production and further marginalizing predominantly female headed households. The majority of flood recession farmers are women.
As the riparian communities are dependent on the benefits from the seasonal flooding, decisions on construction and operation of the Pwalugu dam should consider these benefits and develop plans to compensate communities for any losses incurred. These issues have been discussed at a number of meetings with decision makers and stakeholders in the Volta basin. What is clear is that because of the strong link between natural infrastructure and local livelihoods, local impacts do need to be better recognized and included in decision making around built infrastructure.
'WISE-UP to Climate' stands for 'Water Infrastructure Solutions from Ecosystem Services Underpinning Climate Resilient Policies and Programmes'. The project runs over a four-year period (2013-2017) and link ecosystem services more directly into water infrastructure development, in the Tana (Kenya) and Volta (Ghana-Burkina Faso) river basins. The project is coordinated by a global partnership that brings together the Council for Scientific and Industrial Research in Ghana (CSIR), The African Collaborative Center for Earth System Sciences (ACCESS) - University of Nairobi, the International Water Management Institute (IWMI), the Overseas Development Institute (ODI), the University of Manchester, the Basque Centre for Climate Change (BC3), and the International Union for Conservation of Nature (IUCN).
The project is funded by the International Climate Initiative (IKI) of the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB).
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