Climate resilience: 3 major challenges for better sustainable water management

Challenge n°1: reduce surface runoff from paving aka soil “sealing”

As industrialization and urbanization greatly increase worldwide, the accompanied paving of land surfaces has many negative impacts on water resources. First, impermeable concrete surfaces prevent rainwater from infiltrating the soil, thus limiting groundwater recharge and “sealing” off the soil from precipitation. They also increase runoff and the risk of flooding. Finally, they contribute to the creation of urban heat islands, impacting air quality and the comfort and health of residents, and increase energy consumption through greater use of ventilation and air-conditioning systems. In Paris, for example, the difference in temperature between the city center and surrounding countryside can sometimes exceed 10°C in a single day¹According to the University of Philadelphia..

Reintroducing water absorption into cities through resilient urban planning has therefore become a priority for public authorities. Urban and regional planning policies are increasingly focusing on reducing the use of impermeable surfaces by creating permeable paved surfaces and reintroducing vegetation into cities to reduce runoff and recharge groundwater aquifers.

Challenge n°2: store rainwater

In addition to allowing greater rainwater absorption, urban areas need to be equipped with sustainable rainwater management systems that can collect and store excess rainwater if necessary, before sending it to treatment plants. Current systems are sometimes inadequate and overloaded, as in Paris, New York, and many other older large cities, where sewers and treatment plants are regularly saturated from large storms. During heavy storms, excess wastewater is discharged into the rivers in these cities, polluting the Seine, the Hudson etc.  However, it is possible to address this issue, for example Paris was motivated by the hosting of the 2024 Olympic and Paralympic Games and its desire to host swimming events in the Seine.  In 2015 the city deployed a “bathing plan” made up of various initiatives designed to clean up the Seine. Basins were built to store surplus water during heavy rainfall and return it to the city’s treatment plants after heavy storms. A basin with a storage capacity equivalent to that of 20 Olympic-size swimming pools (!) has been built at the Austerlitz train station. These efforts have greatly improved the water quality of the river and offer a model to other cities that such infrastructure upgrades are possible.

Challenge n°3: support water efficiency in agriculture

The challenges linked to water availability are also a major issue for agriculture, given that 25% of freshwater withdrawals in Europe are consumed by farming, according to INRAE. This figure rises to 70% worldwide, according to the OECD. Falling rainfall in certain regions regularly affected by drought and the lack of water resources compromise the viability of crops, putting food production at risk. For example, during the 2022 drought France saw significant yield declines in grain corn (-16%), sunflowers  (-17%) and soybeans (-12%)²The French Statistics and Forecasting Department of the Ministry of Agriculture and Food (Agreste)..

The General Council for Food, Agriculture and Rural Areas (a French agricultural agency) expects additional water-related costs for agriculture and the agrifood industry to be around 1 billion euros by 2050. Ensuring the resilience of agricultural systems in the face of water scarcity is therefore essential to ensure the survival of farms and food security for all.

This involves water-saving farming practices like efficient irrigation techniques such as drip irrigation and micro-irrigation, where water is supplied directly to the roots of crops rather than being applied to the surface by water cannons and rotating sprinklers. These systems enable water savings of up to 20% by reducing losses through evaporation and runoff.  Already widely used in France for greenhouse crops, they could also be deployed for field crops, as is increasingly the case in the United States.

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The use of sensors and remote sensing systems to effectively monitor and control soil moisture also makes it possible to optimize the use of water resources. Nantes based Agri-tech company Weenat exemplifies this approach, having installed over 20,000 meteorological and agronomic measurement stations in France and other European countries since 2014.  Weenat’s sensors measure wind, air and soil temperature, rainfall and more, and include 10,000 sensors measuring soil moisture to inform farmers in real time of water levels in their crops. According to the company, its technologies have already saved 32 million cubic meters of water. It intends to go even further and is preparing to combine all this data with meteorological and satellite data to offer real-time assessment of the water content of European agricultural soils to the nearest square kilometer.

The planetary freshwater limit was exceeded in 2022³According to the Potsdam Institute and the Stockholm Resilience Center. due to human actions that have profoundly altered the water cycle, affecting the health of the entire planet. It is therefore imperative to tackle water-related issues head-on.  Humanity must enable wastewater reuse, seawater desalination, reduce soil “sealing” from extensive paving, promote rainwater storage and water conservation in agriculture, take action to reduce water leaks in water infrastructure, and generally ensure that water is not wasted.

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About the author, 

Sébastien, Senior Consultant in Alcimed’s Energy, Environment and Mobility team in France