In the Desert, When It Rains It Pours: Safeguarding From Floods and Enhancing the Natural Environment

Floods are among the deadliest natural hazards, impacting a growing number of areas around the world. Afghanistan, Brazil, Indonesia, Italy and numerous countries in Northern Europe have all experienced devastating flooding recently.

One region we don't typically associate with flooding is the Middle East, an arid region characterized by very low water availability and scarcity. However, in April 2024, one of the driest places in the world, the Arabian Gulf, was hit by catastrophic storms and flash flooding that resulted, tragically, in 23 deaths and hundreds of millions of dollars' worth of damages to homes and businesses.

The level of rainfall was unprecedented, with Dubai recording more than 9.8 inches (250millimeters) of rainfall in less than 24 hours. To provide context, the United Arab Emirates typically sees between 5.5-7.9 inches (140-200mm) of rainfall annually.

While it's not possible to link individual storms to global warming, we know that rising temperatures make extreme weather events more likely and studies show flooding in arid zones is increasing globally. Climate change is also causing longer and more severe periods of drought, which in turn reduces the capacity of soil to absorb water, resulting in even greater flood risk. In many places around the world, increased development, population growth and urbanization are further exacerbating flood risk.

Flood resilience is never a one size fits all approach. It's essential that flood management plans address the challenges specific to the region or landscape in question. Arid zones present a diverse array of landscapes, including coastal plains, oasis settlements, floodplains and mountain areas. By working with these natural environments, we can make our communities more resilient to climate change, enhance biodiversity, cool down urban environments and create healthier, more livable places that are functional, beautiful and regenerative.

So, how can we safeguard against flood risks in arid zones while enhancing the natural environment?

The first step is mitigation. With arid zones characterized by dry soil, permeability is low and tends to increase when soil moisture increases. However, during flash floods, infiltration is slow and results in most of the rainfall converting into run-off. Unless water is trapped in swales, detention basins or vegetated areas where roots provide some preferential flow path for infiltration, there's a heightened risk of a damage to infrastructure and the environment. There are several flood mitigation techniques we can harness:

Make drainage sustainable again

Boosting the ground's ability to absorb more water, replenishing aquifers and returning water to the atmosphere through evapotranspiration should be the first port of call. Implementing Green Stormwater Infrastructure(GSI)/Sustainable Drainage Systems and Nature-Based Solutions can effectively manage stormwater run-off and reduce flooding.

Sustainable Drainage Systems use a combination of green infrastructure features such as permeable pavements, green roofs and swales to mimic natural drainage processes. Nature-Based Solutions enhance the ability of the ecosystem to increase infiltration and retain and delay the run-off process. Promoting infiltration and retention of rainwater, Sustainable Drainage Systems and Nature-Based Solutions recharge groundwater aquifers and mitigate the impact of flash floods.

Store the water

Water that can't be absorbed must be stored. Creative storage solutions such as detention basins or floodable parks and plazas provide temporary storage during heavy rainfall, reducing the risk of flooding. These multifunctional spaces are designed to accommodate floodwater without sustaining damage. When designed well, they also act as public amenities improving the quality of life for residents by providing space for recreational activities, social gatherings and cultural events.

Slow the flow

Alongside draining and storing water, measures to slow the flow of water should be introduced. This includes enhancing the landscape and increasing the roughness of water channel surfaces, thereby increasing resistance and reducing the risk of flash floods. For example, terracing and contouring the landscape to mimic traditional farming methods reduces the slope gradient and slows down water flow. Breaking up steep slopes into smaller, terraced steps, forces run-off to travel a longer distance horizontally, allowing more time for infiltration and reducing the erosive force of flowing water. Strategically moderating the flow from tributaries to stagger peak flood times can also significantly mitigate the risk of downstream flooding.

Comprehensive flood defense and ecosystem management

After mitigation comes management. To reduce risk to the most vulnerable areas and maximize resilience, implementing a flood defense plan at the catchment level is vital. By mapping where and how flooding is likely to take place, we can establish system-wide interventions to minimize flooding impacts on communities, critical services and infrastructure.

Non-structural measures to reduce loss or damage from flooding should also be considered, including flood zoning and urban planning, flood forecasting, warning and evacuation and shelter management.

While limiting flooding impacts, it's also critical we maintain floodplains natural function to convey and store water. This essential role supports ecosystems dependent on periodic flooding. Floodplains are diverse, sustainable resources capable of multiple but compatible land uses that serve the community's interests. Flood management plans should recognize the value of floodplains and encourage smart development strategies that maximize their use.

Embrace a coexistence strategy

Climate change means that increased extreme weather events are a reality we can't escape. Communities must recognize and adapt to flood risks, implementing effective mitigation strategies to live safely and sustainably with water's natural cycles.

By embracing flood mitigation and management strategies to address specific challenges of unique topographies, we can create climate resilience, enhance the natural environment and improve people's quality of life.

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