Climate crisis and future water demand

What will happen in the future with water supply? How much will it cost, economically?

by Lorenzo Ciotti
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Climate crisis and future water demand
© Christopher Furlong / Staff Getty Images

One of the biggest problems facing future generations will be the availability, demand and supply of water.

The climate crisis also coincides with a water crisis: in many countries global warming leads to desertification, which coincides with a hydrological crisis.

The water crisis of today is determined first of all by the demographic increase of the last 100 years, which has caused a 600% increase in irrigated agricultural land necessary to meet growing food needs, but also by an increase of over 700% in total water consumption on the planet. In fact, water consumption in the world has increased six times in recent years, at a rate more than double the population growth rate.

Climate crisis
Climate crisis© Christopher Furlong / Staff Getty Images
 

Climate crisis and water demand

The study: Climate change and future water demand: Implications for chlorine and trihalomethanes management in water distribution systems, published in the Journal of environmental management, proposed an interesting perspective on the topic.

The researchers explain:

"The global change in surface water quality calls for increased preparedness of drinking water utilities. The increasing frequency of extreme climatic events combined with global warming can impact source and treated water characteristics such as temperature and natural organic matter. On the other hand, water saving policies in response to water and energy crisis in some countries can aggravate the situation by increasing the water residence time in the drinking water distribution system.

This study investigates the individual and combined effect of increased dissolved organic carbon, increased temperature, and reduced water demand on fate and transport of chlorine and trihalomethanes within a full-scale DWDS in Canada. Chlorine and THM prediction models were calibrated with laboratory experiments and implemented in EPANET-MATLAB toolkit for prediction in the DWDS under different combinations of DOC, temperature, and demand. duration of low chlorine residuals and high THM periods within a day in each scenario was reported using a reliability index.

Low-reliability zones prone to microbial regrowth or high THM exposure were then delineated geographically on the city DWDS. Results revealed that water demand reduction primarily affects chlorine availability, with less concern for THM formation. The reduction in nodal chlorine reliability was gradual with rising temperature and DOC of the treated water and reducing water demand. Nodal THM reliability remained unchanged until certain thresholds were reached.

At these critical thresholds, an abrupt network-wide THM exceedance of 80 μg/L occurred. Under higher DOC and temperature levels in future, employing the proposed approach revealed that increasing the applied chlorine dosage results in elevated exposure to THMs and is not recommended.

This approach aids water utilities in assessing the effectiveness of different intervention measures to solve water quality problems, identify site-specific thresholds leading to major decreases in system reliability, and integrate climate adaptation into water safety management."

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