This 2018 World Water Day, the theme chosen is “Nature for Water” which will explore how we can look to nature to overcome the water challenges of the 21st century.
Ballooning urbanization and climate change are two major factors causing the environmental damage driving today’s water-related crises. Floods, droughts and water pollution are increasing in both frequency and severity, a situation being worsened by our degraded ecosystem.
This year’s campaign is entitled “The Answer is in Nature”. Reforestation, restoration of wetlands and the reconnection of rivers and floodplains will help rebalance the water cycle and allow waters to drain more effectively thereby mitigating flooding and its effects. This is especially important in urban areas. For the first time in history more than half the global population live in cities and that percentage is only expected to grow in the next few decades. Many natural areas have been damaged, destroyed or even paved over, in the rapid expansion of these urban areas. This has led to increased flooding and loss of life in population centers during heavy rains or storm surges. Urban planners need to now start considering these factors when designing cities and towns. It is estimated that by 2050 nearly 20% of the world’s population will be at risk from floods.
Water quality also suffers as cities expand. Less water can soak into the ground to be filtered on its way to re-charge the groundwater table. As more and more surface area becomes impermeable due to construction materials, the amount of run-off is increased. Erosion will increase as more sediment is washed into streams along with other surface pollutants, proving fatal to many aquatic dwellers and entering the water cycle without any filtration. As water demand increases the water table will be lowered and water availability decreases.
Drought is another water issue the world is wrestling with today. The southwest United States has only recently emerged from a severe drought that led to water restrictions in California that the legislature is now considering making permanent. Cape Town, South Africa is currently experiencing its worst drought on record and has imposed daily water restrictions of 50 liters, approximately 1/6 of the average North Americans use. A four minute shower will use 50 liters of water! Even with this tight restriction, Zero Day, the day the water supply is exhausted, is projected to be a matter of weeks away. Initially it was expected to be early March but the rationing and conservation effort of the citizens has pushed it back until July 15th. Hopefully the winter rains will start by then! Cape Town SA is not the only large city with an uncertain water future. Sao Paulo, Brazil, Mexico City, Mexico, and Los Angeles, California have all suffered water shortages and restrictions in the last few years with the BBC warning that London, England may start to feel the water pinch by 2025.
It is also estimated that 1.8 billion people get their drinking water from an unimproved or unregulated source. This could be groundwater or surface water which has no protection against human feces or any other contaminant. By 2050 water demand is expected to rise by 30%.
Only 1% of water is used as drinking water. Agriculture withdraws 70% of the water, mostly for irrigation. Any pollutants in this water can be absorbed by the crops and then later ingested by anyone eating the harvest.
Industry uses an additional 20% of our water. Efforts are currently underway to recycle or reuse much of the waste water to increase our water on hand. Not all uses require the water to be potable. Grey water, as treated waste water is known, is used in many municipalities where water is scarce to stretch the reserves. Tucson, Arizona and San Diego, California are 2 major cities where this has been done quite successfully.
Looking to nature, we can see how water quality can be improved by restoring natural areas. When we create buffers of vegetation along waterways and restore forests and grasslands, we reduce soil erosion.
Wetlands and waterways provide storage locations for water as well as recreational opportunities and increased biodiversity.
Nature based solutions for the most part involve the management of vegetation, soils, wetlands, rivers and lakes. In arid areas, building sand dams can increase the amount of water stored and available for use, thereby extending the growing season and increasing yields. Restoring groundcover can reduce soil erosion and facilitate rainwater absorption and groundwater recharge. When rivers are restored, flood risks are reduced and a food source can be re-established. Wetland revitalization helps with biodiversity and air and water purification. Recreational and occupational opportunities can also be realized with the restoration of ecosystems. Nature can teach us many lessons in water conservation if we are only willing to listen and learn.