The definition of sustainability changes every time we vary the subject or the purpose. So when it comes to the generalized meaning, ‘sustainability’ is meeting the demands of the present without hampering that of the future.
When we give a thought to water sustainability, the very first thing that crosses most of our minds is that we have plenty of water, why link it to sustainability? For that, one needs to be aware that there is plenty of water available, but that is in the case of oceans. The water that humankind demands come from freshwater resources, and they sure are depleting due to various reasons like urbanization, pollution and population growth. Here’s where water sustainability comes into the picture.
Protection of the waterways from pollution, hence providing water that is pure, safe, reliable and convenient to access comes under sustainability. It also includes resilience and adaptability during extreme weather conditions that lead to water scarcity, floods, droughts, etc.
Water is supplied from different sources based on their presence and availability. The sustainable water supply can be said as the major component of integrated water resource management. To ensure that, one needs to take into account the economical, social and ecological considerations. Even the three-fold goals of sustainability consist of 1) economic feasibility, 2) social responsibility and 3) environmental integrity, and all of these are connected/linked to the purpose and use of water.
For an instance, in the case of dams, whether they will provide a sustainable water supply completely depends on the development and population growth on the downstream side of the dam.
We draw water from the ground as well, hence, it must be ensured that the groundwater reduction is controlled. By conserving the total amount of water entering, being utilized and being stored, one can take a step towards groundwater supply sustainability. If declination in water level, streamflow reduction, degradation of water quality are being observed, it indicates that the use of groundwater is occurring in an unsustainable manner. Some common practices that can be followed for sustainable groundwater supply are:
Another important sustainable source of water supply is rainwater harvesting. It can meet the global water demand and can be the most practical supplement to sustainable water supply systems, but there is a particular level of uncertainty due to climate change and land use applications. The areas which receive heavy rainfall during monsoon can design and maintain systems to accumulate water efficiently, ensure that it is not contaminated during collection and make use of treatment systems if it does get contaminated.
There also is a concept called ‘reclaimed water’ where the wastewater from domestic consumption like washing, cleaning (also known as greywater) is recycled and treated, and then reused for various purposes like landscape irrigation, toilet flushing and even for industrial activities. Water reclamation can be said as one of the most important solutions to reduce water stress, at least for the surface and sub-surface water sources.
‘Desalination’ is another process where the excess salt and minerals from the seawater are removed and the water obtained from it is then further utilized for human consumption, irrigation, etc. For the regions with freshwater scarcity along with islands, desalination is potential enough to provide them with an adequate amount of water to meet their demands. This process, however, can prove to be unsustainable due to its high energy demand (for reverse osmosis), and higher costs when compared with other water supply sources. If we combine desalination and technologies that are efficient with renewable energy, we surely could increase the sustainability feature of this supply. But every advantageous process has its demerits. In this case, desalination can cause water pollution as brine would be discharged into the water bodies once the seawater is treated. It can also harm marine life and the process requires high operation costs, which in turn raises the cost of the final product. If a solution to all these shortcomings is found, desalination would be beneficial for water supply sustainability.
The current world raises concern for the conservation and sustainability of water resources and supply. To do that, measures can be taken based on water management and distribution planning. Some strategies which can prove to be very effective on a long term basis can be listed as follows:
Water sustainability is achievable when the efforts are taken collectively and judiciously rather than individually. The key for it is to improve the efficiencies both in water supply and water demand. Reduction in water wastage can have a greater positive impact on sustainability and therefore should be prioritized. Adopting water-efficient technologies and reducing water pollution are the stepping stones to water supply sustainability and should be every individual’s primacy.