Water distribution networks play a crucial role in ensuring access to clean and safe drinking water. However, they can also have significant environmental impacts, especially in the context of a changing climate. To minimize their environmental footprint, it’s important to adopt sustainable practices by implementing energy-efficient technologies.
Freshwater availability: a worsening crisis
Today, freshwater reserves decrease continuously, depleting one of the most important natural resources for human survival and development. It’s easy to understand the urgency of the situation by considering three facts. First, only 0.7% of available water on planet Earth can be found in rivers, lakes and underground aquifers and can therefore be used for drinking water production. Second, the distribution of rainfall in space and time varies. Third, the need for drinking water constantly increases due to population growth and competitive water uses.
The problem is significantly magnified if we consider the effects of climate change on the spatial and temporal distribution of water resources, which may lead to prolonged dry periods and water shortage events.
Trying to meet the annual average and seasonal peaks of freshwater demand, many regional authorities invest in alternative water securing strategies. They import water from other areas and desalinize brackish subsurface water reserves or seawater.
Apart from their profound environmental impacts, these strategies dramatically increase the production cost of freshwater, while undermining the financial viability of local economies. In this context, regional and local authorities should develop strategies to optimize freshwater consumption, especially by reducing the amount of freshwater that is released back to the environment. This is where water distribution networks take a central role.
The role of WDNs and the leakage problem
All water distribution networks (WDNs), regardless of their age and construction materials, exhibit leakages. These result from inherent, functional, and environmental factors, which affect the network, starting at its construction and throughout its operation. Inherent factors include the type of material used, the dimensions and age of the system, as well as its external protection. Functional factors, for instance, are corrosion rates and external stresses. Environmental factors include temperature, infiltration rate, and soil erosivity.
A 2004 study estimated that the global non-revenue water (NRW) volume, which mainly corresponds to leakages, is of the order of 126 billion cubic meters per year. Conservatively, these leakages are valued at USD 39 billion annually, due to the high electricity costs associated with pumping.
Especially in old and poorly maintained networks, water loss ratios are high. They lie at around 70%, meaning 70% of the water volume entering the WDN grid is lost. According to the World Health Organization, worldwide averages for water loss ratios lie at 40 – 60% in developing countries, and 35% in developed countries.
Another impact of water leakages is the potential contamination of drinking water. Leaks in pipes allow contaminants such as bacteria, chemicals and pollutants to enter the water supply. This can pose a high risk to public health.
Non-Revenue Water levels around the world, as of 2018 (© A.V. Serafeim)
How to minimize leakages
To reduce the environmental and financial impacts of water leakages, it’s essential to maintain and repair the distribution network, while detecting and locating new leaks using smart meters. This can be effectively done by using wireless communication to transmit water consumption data and analyze them, in order to identify patterns that may indicate a leak. Additionally, by using pressure management systems to regulate pressures in a distribution network, both the leakage rate and the probability of new leaks can be substantially reduced.
Another important aspect of data management is the use of Geographic Information Systems (GIS) to map the distribution network and identify high-risk areas for leaks. GIS tools allow water distribution companies to visualize and analyze data in a spatial context, providing a more accurate and detailed understanding of their network. This can be useful for identifying areas with high water demand, high-risk areas for leaks, and areas where maintenance and repairs are needed.
Furthermore, a vital step towards effective WDNs management is collaboration between different stakeholders, such as between water distribution companies, municipalities, and community organizations. By working together, these groups can share resources and knowledge, and develop coordinated strategies to detect, repair and prevent leaks. Another example of collaboration is the partnership between water distribution companies, research institutions, and technology companies, towards creating new knowledge and leading the development of state-of-the-art technologies.
In conclusion, reducing water leakages in water distribution networks requires a combination of different strategies and technologies. Advanced analytics and data management can play a key role in detecting, locating and preventing leaks. By integrating and statistically analyzing data from different sources, water distribution companies can gain a better understanding of their network and make informed decisions about maintenance, repair, and water conservation.
Edited by Christina Orieschnig