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Scarcity of Water and Solutions

The availability of clean water for all people ranks among the most crucial environmental objectives. Fortunately, water can be replenished and is hard to destroy. Our fresh water supply is continuously replenished by evaporation and precipitation; nevertheless, the unequal distribution of water on Earth makes water availability challenging.



Mechanisms


There are two forms of water scarcity: physical and economic scarcity. Physical, or absolute, water shortage occurs when a region's demand exceeds the region's restricted water resources. According to the United Nations Food and Agricultural Organization (FAO), around 1.2 billion people live in areas of physical scarcity, with majority of these people living in arid or semi-arid regions. Physical water scarcity can be seasonal; an estimated two-thirds of the world's population lives in locations where seasonal water scarcity occurs at least once a year. Physical water scarcity is predicted to afflict an increasing number of people as populations grow and weather patterns become more erratic and harsher.

Economic water shortage is caused by a widespread lack of water infrastructure or by inadequate management of water resources where infrastructure is present. According to the FAO, more than 1.6 billion people confront economic water scarcity. There is usually enough water to meet human and environmental demands in locations with economic water scarcity, but access is constrained. Mismanagement or inadequate development may result in dirty or polluted water for human consumption. Economic water shortage can also be caused by unregulated water consumption for agriculture or industry, which is frequently at the cost of the general population. Finally, significant inefficiencies in water use might lead to water scarcity, typically due to an economic undervaluation of water as a scarce natural resource.



World map of projected water stress by country in 2040 under business-as-usual scenarios.

Source:Encyclopedia Britannica Inc.


Economic water scarcity is frequently caused by a combination of circumstances. Mexico City, with a metropolitan population of over 20 million people, is a prime example of this. Although the city receives sufficient rainfall, with an annual average of over 700 mm (27.5 inches), decades of urban expansion have resulted in the majority of precipitation being lost as dirty overflow in the sewer system. Furthermore, because the city was originally surrounded by wetlands and lakes, relatively little of the precipitation now drains back into nearby aquifers. Nearly fifty percent of the municipal water supply is obtained in an unsustainable manner from the aquifer system beneath the city. Withdrawals outnumber aquifer regeneration to the point where some portions of the region sink up to 40 cm (16 inches) per year. Furthermore, it is believed that about 40 percent of the city's water is wasted due to leaks in pipes damaged by earthquakes, city sinking, and old age. Many places, particularly poorer neighborhoods, constantly have water shortages, and water is routinely carried in by trucks for inhabitants. Mexico City is one of the world's top cities plagued by economic water scarcity due to historical and present mishandling of surface and ground waters and natural areas, as well as the complexity of being an old yet ever-growing city.



Infographic describing the causes and effects of water scarcity. Water scarcity is divided into two types. It is likely that water scarcity will become one of the world's most serious environmental and economic problems; however, there are several possible solutions that could be employed to prevent it.

Source: Encyclopædia Britannica, Inc./Kenny Chmielewski


Effects


Aquifers are commonly used in areas with minimal rainfall or restricted access to surface water. Groundwater exploitation might jeopardize future water supplies if the pace of removal from the aquifer surpasses the rate of natural recharge. A third of the world's major aquifer systems are thought to be in trouble. Furthermore, the redirection, misuse, and contamination of rivers and lakes for irrigation, industrial, and municipal purposes can cause considerable environmental degradation and ecosystem collapse. The Aral Sea, once the world's fourth biggest body of inland water, has dwindled to a fraction of its previous extent due to the diverted flow of its inflowing rivers for agricultural irrigation.

Fair water allocation is becoming increasingly difficult as water resources become scarce. Governments may be compelled to select between agricultural, industrial, municipal, or environmental interests, and some groups may triumph over others. Chronic water scarcity, particularly in geopolitically sensitive places, can lead to forced migration and local or regional hostilities.


Water crises occur when water supplies drop to critical levels in areas with persistent water scarcity. Residents of Cape Town, South Africa, were confronted in 2018 with the prospect of "Day Zero," the day municipal taps would run empty, the first serious water crisis in any large metropolis. The immediate threat passed without incident due to intensive efforts to preserve water and the fortuitous advent of rain. However, because humans can only survive for several days without water, a water crisis can quickly turn into a complicated humanitarian situation. Water crises were listed third in the World Economic Forum's 2017 Global Risks Report in terms of impact on mankind, after arms of catastrophic destruction and severe weather.


Solutions


Water scarcity demands an interdisciplinary approach. Water resources must be managed in a way that maximizes economic and social welfare while safeguarding ecosystem function. This goal is known as the "triple bottom line": economics, the environment, and equity.


Around the world, a variety of environmental, economic, and engineering solutions have been proposed or implemented. Water conservation activities will surely benefit from public education, and all public and environmental policies must rely on strong science to undertake sustainable resource management programs.


Environmental policy


An essential strategy in the struggle against water scarcity is the preservation and restoration of ecosystems that naturally gather, filter, store, and release water, such wetlands and forests. Other ecosystem services offered by freshwater habitats include the recycling of nutrients and protection from flooding. These ecological processes, which have economic and social significance, can only be supported by an intact ecosystem. However, natural places are frequently destroyed or degraded for more immediate economic benefits without considering their ecological worth.


Economic and social solutions


Several studies have found that increased water costs reduce water wastage and pollution while also funding water infrastructure improvements. Price rises, on the other hand, are widely and politically unpopular in most locations, and policymakers must be mindful of how such increases may affect the poor. A water levy on high users could discourage inefficient water consumption in industry and agriculture while remaining unaffected by home water rates. While consumers would undoubtedly see higher product prices as a result of increasing production costs, such a levy would ideally help divorce economic growth from water use. Rebates for the replacement of water-wasting appliances, such as toilets and shower heads, are a widespread and cost-effective option in many places.


Pesticide and fertilizer runoff, as well as animal waste, are major contributors to water pollution in industrial agriculture. Policies that encourage organic farming and other environmentally friendly farming methods help to safeguard water sources from agricultural pollution. Industrial causes of water pollution are typically easier to control than point sources of contamination.



Engineering technologies


Traditional engineering may address a multitude of water scarcity concerns, often with immediate benefits. Infrastructure repair is one of the most obvious solutions. Finding ways to reduce installation and maintenance costs, particularly in developing nations, as well as designing technical solutions that help the environment and address the effects of climate change, are difficulties in infrastructure repair.


Given that agriculture consumes over 70% of all freshwater supplies, another key answer is to enhance irrigation systems. Many agricultural areas rely on simple flooding, or surface irrigation, as their primary irrigation method. Flooding, on the other hand, frequently inundates fields with more water than crops require, and large volumes of water are lost due to evaporation or transit from its source. Farmers can assist minimize inefficient water usage in agriculture by educating them about the potential water loss from such practices, setting explicit water-use reduction targets, and funding irrigation upgrades and water-conservation technologies.


Desalination has been advocated as a solution to water scarcity issues in places that have access to brackish groundwater or seawater. Indeed, in a number of heavily populated dry regions, such as Saudi Arabia, desalted water is already a major source of municipal water supply. However, conventional desalination equipment takes a significant quantity of energy, typically in the form of fossil fuels, making the process costly. As a result, it is mainly employed only in areas where fresh water is not economically available. Furthermore, the quantities of greenhouse gas emissions and brine effluent produced by desalination plants offer substantial environmental difficulties.


In cities or towns where the population is rising and water supplies are limited, wastewater can be a valuable resource. In addition to relieving pressure on limited freshwater supplies, wastewater reuse can improve the condition of streams and lakes by lowering harmful effluent discharges. Reclaimed and reused wastewater can be used for agricultural and landscape irrigation, groundwater recharge, or recreational uses. Although reclamation for drinking or home use is technically conceivable, it encounters enormous public opposition. Water-recycling plants are becoming more popular in cities around the world. The use of wastewater to nourish algae or other biofuels has been advocated as a technique to develop these water-intensive crops more efficiently while also encouraging sustainable energy sources. Also see wastewater treatment.


Rainwater collection for nonpotable purposes, such as gardening and laundry, can greatly reduce the demand on public freshwater sources as well as the burden on stormwater infrastructure. In major cities, the savings in demand and supply of drinkable fresh water can be enormous, and a number of water-stressed municipalities, such as Mexico City, are actively building rainwater harvesting systems. Rain barrels and other rainwater gathering systems are encouraged and even subsidized in many communities. However, in other locations, particularly in the western United States, rainwater harvesting is considered as a water rights issue, and such collections are restricted. Furthermore, catchment systems that collect runoff and enable it to soak into the ground are beneficial for groundwater recharge.


Reference: Encyclopedia Britannica: Water Scarcity

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