In November and December of 2015, the South Indian states of Tamil Nadu, Puducherry and Andhra Pradesh suffered from historically destructive flooding. These El Nino-induced floods inflicted an estimated $3 billion loss on the Indian economy and displaced more than 1.8 million people.

Globally, floods and droughts cause hundreds of billions of dollars of crop damage and loss of livestock and human lives each year. Unfortunately, the frequency and scale of extreme weather events like the floods in India are expected to increase due to climate change. Yet research also shows that, if effectively managed, floodwaters can be leveraged to intensify agricultural production, for example by supporting irrigation and additional crop cycles.

National governments and other decision-making bodies are increasingly seeking ways to manage water variability brought on by increasingly volatile weather. Scientists from the CGIAR Research Program on Water, Land and Ecosystems (WLE) are working to address flood-related risks and to find ways to harness floodwaters for productive use.

Information can provide early warning, improve planning

One avenue for increasing societies’ resilience to, and productive use of, floods is to provide access to information about flood events.

In South and Southeast Asia, scientists have developed a geospatial flood inundation mapping approach that, based on satellite images, can show floodwater extent and depth on land in near real time, with accuracy down to ten meters. Such maps have proved their worth as a tool for disaster relief planning, by helping authorities make immediate, medium and longer-term plans for recovery and reconstruction.

Flood risk mapping, Cambodia.

IWMI.

The maps can also support governments assess a flood event’s total economic impact after the fact and inform their future decisions on, for example, where to put preventive measures in place.

Another promising aspect of this research is flood insurance.

“Affordable insurance for flood-related crop loss is rarely available, but remote sensing and flood modeling tools could be used to identify critical parameters like flood duration, depth and inundation extent,” explains Giriraj Amarnath of the International Water Management Institute (IWMI). “With this information, insurers could more accurately identify recurring patterns of floods in a particular area and thereby be able to offer farmers reasonably priced products for extreme weather events.”

Scientists believe that information and communication technology can help mitigate the adverse impacts of floods by giving farmers and other users fast access to precise information. For example, a new application for handheld devices, called WetIn, provides users with early flood warnings for the Niger-Benue river systems in Nigeria. The application is expected to support local authorities’ flood response planning by predicting rises in water levels three to four days in advance of floods.

Innovative solutions leverage floods for good

Beyond finding ways to more readily access and share information about floods, scientists are also piloting large, nature-based solutions for harnessing flood waters.

For example, a new concept called underground taming of floods for irrigation is being tested in India and will be piloted in Bangladesh. It is an innovative, community-based approach that aims to address the double challenge of floodwater destruction and groundwater depletion in areas where both are problematic at different times of the year. When water runs high in rivers and canals and flooding is imminent, scientists propose to divert this water into groundwater aquifers via small ponds or dams.

“Essentially, the idea is that it would work like a community savings bank,” explains Paul Pavelic of IWMI. “Local communities deposit water underground when there is an excess and withdraw it later, such as during the dry season, when it can be used for irrigation.”

The solution is being piloted in Rampur district in northern India, and government officials have earmarked the concept for implementation across the district under a water management program led by the government.

In a similar vein, WLE scientists are promoting the perspective of safeguarding natural infrastructure for managing and benefiting from floods. For example, giving space for rivers to flow over their floodplains can provide opportunity for exploiting the benefits for fisheries, flood recession agriculture and grazing.

In the Tana River basin in Kenya, such benefits of flooding are being compared with those obtained from more regulated flows, like those required to maximize hydropower production, to fully assess the trade-offs and synergies that may be achieved through alternative development pathways. The idea is that by harmonizing the planning and management of both built and natural infrastructure, it is possible to achieve the best of both worlds: maximizing the benefits and minimizing the costs of flooding. 

Women transplant rice in an flooded paddy field following the traditional rice planting techniques in Karnal State in Haryana, India.

Prashanth Vishwanathan/CCAFS.

The incredible economic, human and environmental costs from extremes in weather and water insecurity can be managed if the right tools and approaches are utilized. WLE scientists continue to support national governments and other decision makers by developing new tools that can increase access to information about floods and by piloting innovative, nature-based solutions that can leverage floods for poverty reduction and food security.

Acknowledgments

The solutions mentioned in this article are being developed by the following projects:

• Assessment of floods and droughts: Improved solution for mitigation and risk management in South Asia led by the International Water Management Institute (IWMI) in partnership with regional institutions. See also IWMI’s rapid emergency response mapping website.
• Mitigating major floodwater impacts in Asia: The subsurface solution for damage control and livelihood enhancement led by the International Water Management Institute in partnership with the government of India and other regional institutions. And, Piloting and upscaling an innovative underground approach for mitigating urban floods and improving rural water security in South Asia, supported by the CGIAR Research Program on Climate Change, Agriculture and Food Security.
• Water infrastructure solutions from ecosystem services underpinning climate resilient policies and programmes (WISE-UP to Climate) led by the International Union for the Conservation of Nature in partnership with  International Water Management Institute and other institutions.