Cities and Water: Facing New Challenges
How are Cities Finding Solutions for Water Scarcity and Quality Challenges?
Of all the water on Earth, saline water in oceans, seas and saline groundwater make up about 97% of it. Only 2.5–2.75% is fresh water, of which 1.75–2% is frozen in glaciers, ice and snow; 0.5–0.75% exists as fresh groundwater and soil moisture, and less than 0.01% as surface water in lakes, swamps and rivers. Fresh water sustains human life and is vital for human health. It might seem how little fresh water resource we have, to sustain a human population of 7.5 billion on the earth, besides that of terrestrial animals and birds. However, the truth is that there is enough fresh water for everyone on Earth, particularly from the ground. Ground water is the world's second-largest collection of freshwater and the most harnessed source for human use. It gets collected from rainfall that seeps underground into aquifers and reservoirs beneath the land surface.
Of the 2.75% of the earth's water that is fresh, the largest majority is in the polar icecaps. 21% of our .036% of the global fresh water supply is in the Great Lakes in the US.
A recent research shows the distribution of 'modern groundwater' around the world and how deep these resources would be if pooled above ground. Though the distribution is uneven, there is ample water for all human uses and needs.
What does Modern Groundwater mean?
The age of groundwater is important with respect to its extraction and use. According to the research, young and old groundwater are fundamentally different. Old groundwater (more than 100 years old) is found at greater depths and sometimes contains arsenic or uranium and is usually saline, more than ocean water. More importantly, it is no longer a part of the active water cycle, which means most of it isn't usable by humans. In contrast, modern groundwater (less than 100 years old) is still a part of the active water cycle, and has the capacity to renew itself through rainfall or melting snow.
Physical and Economical Water Scarcity
Water availability or better still water scarcity is defined in terms of its potential for per capita use. An area is experiencing water stress when annual water supplies drop below 1,700 m3 per person. When annual water supplies drop below 1,000 m3 per person, the population faces water scarcity, and below 500 cubic meters "absolute scarcity". Water scarcity affects more than 40% of the global population and is projected to rise. It is estimated that 783 million people do not have access to clean water and over 1.7 billion people are currently living in river basins where water use exceeds recharge. Population growth, urbanization, industrialization and changes in weather pattern are all putting pressure on our cities and their access to safe and secure water supplies.
What is Physical and Economic Scarcity?
Physical water scarcity is the situation when there is not enough water to meet all demands, such as those required by an ecosystem to function effectively. Arid regions frequently suffer from physical water scarcity. It also occurs where water seems abundant but where resources are over-committed.Economic water scarcity is caused by a lack of investment in water infrastructure or insufficient human capacity to satisfy the demand of water despite an adequate source of water.
CDP: Global Disclosure System
CDP, formerly the Carbon Disclosure Project, runs the global disclosure system that enables companies, cities, states and regions to measure and manage their environmental impacts, by building a comprehensive collection of self-reported environmental data.
569 cities and 1,432 companies globally have disclosed water management information through CDP in 2016. Released for World Water Week (27 August – 1 September) a new infographic report, Who’s Tackling Urban Water Challenges? shows the first-ever comprehensive dataset of global water action by cities and companies produced. Following are some the chief insights on water governance:
- 63% of cities globally foresee a risk to their water supply from weather related events.
- 43% of the companies disclosed that their organization is exposed to water related risks that could substantively affect their business operations. Water impacts have costed them $14 Bn in 2016 - like loss of production.
- The three top water related risks are (a) Declining Water Quality (b) Increase Water Stress and Scarcity (c) Flooding. 132 cities reported declining water quality as a risk, while 196 cities cited water stress and scarcity problems and 103 reported flooding.
The Future of Water
Working together with all stakeholders will holy the key to successful water management in cities and companies. From the CDP research, it is already evident that a good number of them are already taking very determined steps towards effectve water management. Some of them are
Water stress is already creating problems around the world. Scarcity has US municipalities and states, farmers and cities, challenging each other. The recent storms in 2017 have caused major devastation from Florida to Texas, and from the Virgin Islands up to Puerto Rico. New approaches and technologies can help solve these problems, but nothing will end our need for water to live as human beings on a planet that has a limited supply of fresh water.