Nature-based solution to disaster risk reduction

16 Mar, 2021 - 00:03 0 Views
Nature-based solution to disaster risk reduction

The Chronicle

Fortunes Matutu
Zimbabwe has increasingly become prone to natural disasters such as cyclones, drought, inclement weather and whirl winds, most of them attributable to climate change.

In previous years, many people lost their lives, had their property destroyed and livelihoods affected because of these disasters.

In February 2017 an estimated 20 000 homes were destroyed and approximately 130 000 people were directly affected by Cyclone Dineo.

Widespread flooding took place in Zimbabwe, with Mutare, Chiredzi, Beitbridge and Gwanda particularly hard-hit. At least 271 people were killed by the storm and damage exceeded US$200 million. In March 2019 Cyclone Idai and subsequent flooding affected over 270 000 people. The storm and landslide caused the death of 340 people in Manicaland while roads and infrastructure were destroyed.

Post-disaster assessment clearly illustrated that, along with disaster preparedness, environmental management – forests, goes a long way in reducing the risks and vulnerabilities associated with natural disasters. We have only now come to realize that taking care of our natural resources and managing them wisely not only assures that future generations will be able to live but greatly reduces the calamities’ hazards. Conserving and maintaining the natural environment- the forests, wetlands, groundcover and riparian vegetation – helps in disaster risk reduction and building community resilience against the impacts of climate change.

Trees and forests are important in dealing with indications of climate change, whether they are heat waves, drought, flash floods, whirl winds, frost and other extreme weather conditions. Trees reduce the damage caused by droughts and floods. Although a drought is a natural disaster, it is made worse by deforestation. If there are not enough trees around, floods also become worse.

When it’s raining trees and forests control storm runoff. Their leaf canopies help reduce erosion caused by falling rain through capturing and storing rainfall in the canopy and releasing water into the atmosphere through evapotranspiration. Roots take up water and together with dead leaves create conditions that promote soil infiltration. Furthermore, trees reduce the rate of soil erosion and land degradation.

They do this by protecting the soil from the impact of rain drops by binding soil to with their roots and transpiring large amounts of water, which counteracts very wet soil.

During a flood, trees absorb some of the water and slow down the rain run-off. Their roots open up the soil and let the water get in instead of running along the surface. If most trees are cut down, nothing covers the ground. Without trees, nothing slows down a flood.

Windbreaks are one of the most essential functions of trees and important in reducing disasters from winds. They shield buildings and roads from whirl winds and heat waves to minimise damage. A few trees can be effective windbreak but the choice of species planted has to be carefully considered around homesteads. Ideally one could choose a tree species that will not damage their property, is of low maintenance, is preferably an ever-green tree and has other benefits either ornamental or fruits. The choice of species for windbreaks should also be dependent on the climatic conditions of the area.

Parks, green spaces and canopies have a cooling effect during hot days; plants absorb water and then release it through evaporation, in the same way sweating keeps us cool. This is particularly important during hot days and heat waves. A place with trees can record up to 5 Degrees Celsius lower temperature that one without.

In times of drought most indigenous fruit trees continue to be productive offering a nutrition escape to the community. Some households and communities go on to process, value-add and sell the non-timber forest products to boost household income and expand their livelihood options.

Wetlands are not only “kidneys of the environment”, that absorb waste and pollutants but also function as natural sponges that trap and slowly release surface water, rain, groundwater and flood waters. Wetland vegetation also slows the speed of flood waters and distribute them more slowly over the floodplain.

To reduce disasters wetlands need to be protected and preserved. Houses and infrastructure built on wetlands are likely to collapse or fail, and inevitably flood. It’s simply disaster waiting to happen. Farming on wetlands and stream bank cultivation results in siltation and choking of rivers and streams. Fertilizers used eventually cause eutrophication and loss of biodiversity.

This all reduces the water carrying capacity of the wetlands and water bodies creating opportunities for flooding while not managing to supply water during the dry season.

Most wetlands are located on floodplains with capacity to temporarily store flood waters during high runoff events hence contributing to disaster risk reduction. Wetlands can reduce the severity of downstream flooding and erosion by holding back some of the flood waters and slowing the rate that water re-enters the stream channel.

Stream bank cultivation is one of the leading land-based activities causing degradation of the riverine ecosystems increasing vulnerability to disaster. It involves cultivating within 30 metres from the highest flood level of the water body. Stream bank cultivation is not sustainable to the environment and disaster risk reduction. It causes the environment to fail to control soil erosion, siltation and runoff.

This eventually means waterbodies hold water for a very short period of time. During the dry season people and livestock suffer from lack of water especially in times of drought, even boreholes dry up as they fail to charge. It has been noted that in times of floods, most irrigation schemes practising stream bank cultivation incur huge loses. They do not only lose their crops but expensive irrigation equipment is washed away in the river/stream.

Siltation fills water bodies and reservoirs with sand and clay soil to hold less water. Such places become more susceptible to floods even with little rainfall. This is because the river or reservoir “throws back” the water into land causing adversities to the community and livestock.

There is a clear need to put an emphasis on the importance of natural resources management in the entire disaster management cycle of prevention, preparedness, assessment, mitigation and response. Natural resources management must be central in any disaster risk reduction planning for both short term and long-term solutions. Alternatively, people and planners can integrate environmental concerns into planning for relief, rehabilitation, reconstruction and development.

We need to pay more attention to natural resource management for disaster prevention and reduction; and environmental conditions that lead to disasters. Any disaster preparedness plan should thus have a special focus on natural resources management. These offer cheap and sustainable solution to disaster risk reduction. Good environmental practices will go a long way in reducing vulnerability to natural and human-induced disasters and can be central to building reliance in the communities. Furthermore, well managed natural environments do not only enhance disaster resilience but also contribute to national socio-economic enhancement and biodiversity.

Below are some environmental management practices we can practise for disaster risk reduction:
· Sustainable utilisation of natural forests
· Planting of trees as windbreaks and along steep slopes (to avoid landslides)
· Maintenance of trees in urban areas or at homesteads – pruning or pollarding and cutting down dead trees
· Preservation of riparian vegetation
· Preservation of wetlands – avoid settling or farming on wetlands
· Watershed management
· Restoration of degraded land
· Avoiding stream bank cultivation
*Fortunes Matutu is a forester with the Forestry Commission and has a special interest in social forestry.

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