Water Conservation Strategies for Sustainable Development
Water is one of the most essential elements to survival. Globally, the amount of available water is rapidly decreasing, affecting availability and access for potability, sanitation, and agriculture. Water scarcity is an urgent and growing problem.
Water scarcity is defined as the lack of available, safe water and water supplies to meet the needs of the community. Statistics show that, globally, 2.1 billion people lack the access to water that is safe to consume and 4.5 billion people lack access to services of sanitation. Estimates are that 40% of the global population is affected by water scarcity, and this number is predicted to increase (United Nations n.d.-a). The significance of access to potable water is clearly articulated in Sustainable Development Goal (SDG) 6, “Ensure availability and sustainable management of water and sanitation for all.” The targets of SDG 6 cover all aspects of both the water cycle and sanitation systems, and the connection of SDG 6 to the attainment of the SDGs overall can be found in the relationship between water and health, education, economics, and the environment (United Nations n.d.-b). Sustainable Development Goal 6 has six subsections of targets to be reached by 2030. These include universal access to safe, affordable potable water, access to adequate sanitation, reducing water pollution by reducing chemical dumping, increasing sustainable withdrawals, creating integrated water resources management, and improving protection for natural ecosystems that provide water. SDG 6 also includes goals of cooperation and participation at both a local and international level (United Nations 2018). Water is crucial for energy production, food production, and every ecosystem including human. Globally, 70% of water withdrawals are used in agriculture, around 75% of industrial water withdrawals are used in energy production, and 80% of untreated wastewater flows into natural ecosystems (United Nations n.d.-a).
A water footprint is the quantified value of water consumption and is the water used in production processes for goods and services. There are three types of water that contribute to this water footprint, and they are categorized as blue, green, and gray water. Blue water is defined as freshwater evaporated from surface water and includes groundwater. Green water is water that has evaporated from rainwater that becomes stored in the soil, and gray water includes polluted water resulting from human use and production activities (Hoekstra and Mekonnen 2012). The use and creation of these water types affect the limited supply of naturally occurring water.
Water, Pricing, and Scarcity
A main contributor to the overconsumption of water is its pricing. Water is considered a normal good, and because of its low price, it is consumed on a want basis instead of a need basis. This results in the overuse of water. The system of setting prices leaves out externalities, so the price of water is skewed by perceived abundance on the supply-side and market power on the demand-side. Different countries have different access to different amounts of water resources and have different resources for recycling and treatment of water leading to variation in value and cost (Skene and Murray 2017, 97).
Another varying measure of water is the groundwater footprint. This varies from the general water footprint because it measures the land area required to supply sufficient rainwater to underground systems. The more land required, the less sustainable the use of groundwater. While all countries vary in their footprints, globally 131 billion square kilometers of land are required based on the footprint measurement (Skene and Murray 2017, 99); the magnitude reveals the unsustainability of the present use of groundwater.
Presently, there is a global water crisis emerging. There are solutions that have been proposed: a soft water path and a hard water path. The soft water path focuses on demand to reduce the use and waste of water and on decentralizing supply to disperse the water as wide as possible (Skene and Murray 2017, 100). The hard water path focuses on supply and on the centralization of water by using dams and boreholes to contain large amounts of water (Skene and Murray 2017, 100). The hard water path focuses on the future and is based on forecasts of future water needs based on the current trends. The soft water path focuses on back-casting, what is needed to achieve the current goal.
Water vulnerability measures water’s potability and the amount of potable water. Developing countries have the highest need for access to safe water. Lack of safe water and sanitation cause 80% of illnesses in developing countries. The lack of sanitation creates an increased vulnerability and lack of safety for women (Global Affairs Canada 2017). Developing countries also lack access to safe drinking water. Their water is highly contaminated and causes many diseases and health impacts due to contamination by bacteria and viruses. Escherichia coli, Vibrio cholerae, and acute bacillary dysentery are a few bacterial pathogens. In addition, the most common viruses are often found in water sources and lead to infant diarrhea, which can become dangerous and fatal. These viruses cause over a million deaths annually (Sudha et al. 2012). In the past decade, 1.3 billion people gained access to safe drinking water in developing countries. Globally 2.1 billion still lack the access (United Nations n.d.-b). The relationship between potable water access, sanitation, and morbidity and mortality is the principal reason for the United Nations adoption of SDG 6. These conditions are consistent with poverty and poverty elimination is central to the SDGs. Furthermore, lack of safe drinking water and sanitation are also consistent with a lack of sustainability related to population, health, and political and economic stability (United Nations n.d.-c).
Agriculture requires water and accounts for 70% of water utilization in developing countries (Lawson and Lyman 2007). The water intensity places harder burdens on developing countries; in developed countries the water utilization is lower. For example, in the United States, only 37% of water withdrawals are used for agriculture (Weil 2013). Developing countries have inefficient methods of irrigation and agricultural practices, leading to excessive withdrawals and slow replenishment. Their practices also lead to deeper water tables, highlighting the depletion risk within these countries (Lawson and Lyman 2007). A water table measures how deep the ground is filled with water. Water tables have gone through ups and downs in their depths, and the speed of climate change is leading to deeper water tables and drier surfaces. As a result, even deep water tables are showing evidence of depletion (Nijp et al. 2014). Developing countries do not have the necessary finances to expand their water supplies, and their low tariffs on water lead to further wasteful use (Lawson and Lyman 2007). In developed countries, water consumption is at high levels due to large systems of irrigation and consumer overconsumption (Haddeland et al. 2014). In just the United States, an average family consumes 552 gallons of water on a daily basis (Weil 2013). These human impacts are increasing the global scarcity of water.
Further exacerbating water access and availability is the speed of man-made climate change. Climate change is leading to rapid increases in the rate of snowmelt and runoff. The pace disrupts water storage because of the early, unexpected runoff. Reservoirs and dams presumably built to collect this water are not capable of holding the rapid accumulation, resulting in flooding, which has been observed on a global level. The inability to capture water is a contributing condition to limiting the supply of usable water (Zellmer 2012). To counter natural shortages and emerging risks, human intervention through technology has been focused on desalinization of sea or salt water sources and also cloud seeding. Further, given the use of water in agriculture, there has been a technology focus related to irrigation and bioengineering drought-resistant crops.
Animals and Plants
Producing animal products accounts for around a third of global water consumption. The production of a single egg requires 53 gallons of water, and one hamburger requires 660 gallons of water. Up to 33% of freshwater consumption is from animal agriculture (Mercy For Animals 2018). Livestock’s blood is composed of 80% water, requiring high levels to maintain proper hydration (Ward 2019). This is greater than the levels of water in human blood. A human requires 2.7 l for women and 3.7 l for men of daily water consumption to survive (Mayo Clinic 2017). Animals are composed of more water, so they require much more water to survive. For example, a milking cow can require over 150 l of water daily depending on its level of production (Ward 2019). These large water needs to animals only make up a third of global water consumption. Seventy percent of blue water collection is used for agriculture and will increase by another 19% in the next 30 years from just irrigation consumption (Weltagrarbericht n.d.). For irrigation alone, almost 70% of freshwater withdrawals are used (United Nations n.d.-a). These withdrawals used for plant growth are extremely variable due to climate effects. For example, a plant in a hotter, drier climate requires more daily water than one in a cool, humid climate. Standard grass water consumption can vary from 1 mm to 10 mm of daily water based on the temperature and climate zone (Brouwer and Heibloem n.d.).
Agriculture requires immense amounts of water. Water used for agriculture is withdrawn from surface water areas likes rivers, reservoirs, and lakes, from groundwater, and from rainwater. The water withdrawn for agriculture used for irrigation totals to almost 90% of consumption use (Houser et al. 2015). Increased dependence on surface water has caused an increase in the depletion of surface water areas. An additional problem is soil and ground water pollution. Fertilizers and other chemicals used for agricultural purposes increase the levels of pollution in the soil and cause moisture deficiency in the soil (Houser et al. 2015). Nitrogen, an important chemical in fertilizers can become a harmful pollutant to groundwater. Excessive amounts used leads nitrates to enter and invade water. Nitrates in groundwater, a major drinking water source, causes fatal diseases to infants and nitrosamines which can be cancerous (Huang and Lantin 1993).
Several methods and strategies exist focused on conserving water via new irrigation systems. This modernization of irrigation infrastructure saves water without sacrificing agricultural production. Trickle irrigation should replace sprinkler irrigation (Atkinson 1979). Trickle irrigation applies water directly onto the surface by the root of the plant. This uses less water because it focuses on areas that need watering instead of spraying the water everywhere in a space that has plants (Atkinson 1979). This system eliminates weeds because there is less water between the plants where sprinkler irrigation would’ve created moisture.
Another method of water-saving irrigation is irrigation using reclaimed wastewater (Asano 1987). Wastewater is water that has changed in quality due to use and is no longer usable for drinking or agriculture. Wastewater can be broken down into domestic wastewater, industrial, and infiltration-inflow. Domestic water is the water supply of the community that is used, inflow is the flow of storm water into the sewage systems, and infiltration is groundwater that has improperly entered the sewage systems (Asano 1987). The process of wastewater purification starts with a sewage system that drains and screens water. Then the water enters a chamber that removes grit from the water, known as preliminary treatment. Next, primary treatment sends water to primary settling tanks which purify the water by separating particles out of the water. Next, secondary treatment uses bacteria to consume the remaining contaminants in the water. These contaminants removed turn to sludge, and the treated water is inspected with extremely high standards to ensure highest level of safety of water (Yoneda 1980). The result of the purification process is reusable water available for irrigation. The sludge of contaminants from the secondary treatment is mixed together and heated to produce biogas. Activation of sludge is used for both electrical and thermal energy. The facility that is treating wastewater uses the sludge for energy production. By producing their own electricity and heating, they become self-reliant for energy consumption (Yoneda 1980).
Organic farming is another sustainable method of agriculture that reduces reliance on fertilizers and harmful chemicals. Developing countries have the most pesticide poisonings because of their misuse of the pesticides, due to their lack of access to information and efficient uses (Ravnborg et al. 2013). Organic farming focuses on sustainable soil and ecosystem health. Instead of changing ecosystem functions to produce a desired outcome, organic farming relies on the natural ecosystem functions to produce wanted results (Diekmann and Polacek 2013). Organic fertilizers are made from organic materials like manure or compost. Using these natural fertilizers and promoting sustainable soils have led to increases in organic carbon levels (Gattinger et al. 2012). Working with organic farming to restore and sustain soil health is the reduction of tillage systems. Tillage causes erosion of soil and shrinking of its pore space for water. The removal of these tillage systems promotes soil moisture increasing its sustainability and organic makeup (Mäder and Berner 2012).
Water and Desalinization
Salinity of soil measures the concentration of salt in the soil. High salinity is dangerous to agriculture because it prevents crop growth. 20% of agricultural land and 50% of cropland globally is over-concentrated with salt (Xu et al. 2014). Desalinization is the process of removing the excess salt minerals from the soil, so it can be used for agriculture. Methods include heat distillation, ion extraction, ion exchange, electrodialysis, freezing desalinization, solar humidification, and iceberg towing (Schutt n.d.). Heat distillation is heating water to the point of evaporation and condensing the vapor to create freshwater (Schutt n.d.). Ion extraction is the use of chemicals or electricity to remove ionized salts from the water (Schutt n.d.). Ion exchange is replacing the ions from the sea water with ions from a resin (Schutt n.d.). Electrodialysis uses electric currents to attract the ions. The specific current only allows the positive ions to escape the water’s membrane to ensure only necessary elements are removed (Schutt n.d.). Freezing desalinization involves freezing water because salts are not included in the components of ice, automatically removing the components (Schutt n.d.). Solar humidification uses solar energy to increase water vapor creation. The vapor is condensed, as in the heat distillation method (Schutt n.d.). Iceberg towing is using icebergs as a freshwater source and transporting parts of the iceberg to land (Schutt n.d.).
Rainwater is a major source of water. Too much water is held in clouds and not released. This water could be used effectively to reduce water scarcity. Cloud seeding is the concept of getting the clouds and the atmosphere to release this stored water. The water needs to be at a temperature low enough to increase the weight of the water, so it is released and falls from the air. Cloud seeding is purposefully modifying the weather to increase this water precipitation. Silver iodide is used to seed the clouds to promote the precipitation. Silver iodide imitates ice crystals. The seeding causes the water in the air to attach to the silver iodide, giving them the weight necessary to drop (Baum 2014). This increases rainfall, increasing supply of water that can be collected and used.
Attempts have been made to create drought-resistant crops in order to improve agricultural systems. Genetically modifying crops to become drought-tolerant or drought-resistant is an expensive, failing process. Droughts have a variety of types and causes, so engineers cannot prevent all of these from affecting agriculture (Gurian-Sherman 2012). These attempts are small in number and success, so the goal of water conservation has not occurred (Gurian-Sherman 2012). Major problems include the limits of genetic engineering, drought variation, and soil interference (Gurian-Sherman 2012). A few genes can be modified at a time, and these few cannot be made completely drought-tolerant. There are several forms of droughts based on severity and timing in season. Soil quality, which is not modified, reacts to droughts and impacts the crop’s ability, even with genetic modification (Gurian-Sherman 2012). The genes changed to tolerate the drought can also lead to other problems like slower growth rates (Gurian-Sherman 2012). There are also so many unknowns to the effects of attempting to create drought-resistant crops. Genetically modifying agriculture to resist droughts is an expensive, counterproductive method of water conservation. Modifying farming and breeding approaches are more cost-effective and successful in conserving water (Gurian-Sherman 2012).
Water and Sanitation
In developing countries, a lack of access to sanitized water is the leading cause of death for children under 5 years old; accounting for approximately 1,000 deaths of these children daily is poor sanitation of water (“Water, Sanitation and Hygiene,” n.d.). Sanitized water means water purified to a point where drinking it is completely safe and does not come with risk of infection or disease. The large amounts of contaminated water around the globe makes sanitization difficult. This leading cause of child mortality is the lack of drinking water and sanitation, causing diarrhea so extreme that the children die. 780 million people around the globe have no access to sources of safe water (“Global WASH Fast Facts,” n.d.). Poverty and disease stem from a lack of access to sanitization. Contaminated water leads to infections like the Guinea worm disease. GWD is a parasitic infection that consists of worms coming out from one’s body via blisters (Hopkins and Foege 1981). This is spread through the drinking of unsafe water. Trachoma, which leads to blindness, comes from poor sanitation (Treharne 1985). Without facilities to safely remove waste from human contact, people turn to open defecation (“Water, Sanitation and Hygiene,” n.d.). This creates two major problems. One is for women who have to wait until it is dark out to avoid assault, interfering with their natural bowel movements. The other is fecal matter becomes exposed in the environment seeps into consumed resources, increasing disease prevalence (“Water, Sanitation and Hygiene,” n.d.). Poor water sanitation is a danger to education. Children, usually girls, are sent to find and collect water for their families, preventing them from getting an education because of the time spent looking for water sources (“Water, Sanitation, and Hygiene,” n.d.). By improving sanitation and increasing quantities of safe water, “there is the potential to save the lives of 840,000 people who currently die every year” due to the lack of safe water and sanitation (“Water, Sanitation and Hygiene,” n.d.).
Modifying and creating infrastructure to prevent runoff of contaminated water into freshwater sources will increase sanitation. This will increase the volume of safe drinking water, as well as take away the risk of how safe it really is to drink. One method to collect water and increase sanitation is through rain catchment systems (Stevenson 2008). These function to give the individual control in collecting their water and using it to their needs. The system connects a tank that collects water through a gutter, so rain water runoff is collected and used instead of lost and wasted (Stevenson 2008). Especially in poor, developing countries, every drop of water is necessary, so this system makes extreme differences in their hygiene. Another solution for the distribution of freshwater especially in poorer countries is through solar-powered water pumps (“Solar-Powered Water Pumps,” n.d.). These pumps function to distribute 30,000 l of clean, safe water every day. A hole is drilled far down to reach a water source, usually around 100 m. Then solar panels are used to power a motor that pumps the water from underground into a tank. This tank is connected to pumps throughout the community via a system of pipes increasing water availability and safety (“Solar-Powered Water Pumps,” n.d.). This saves the children’s energies and times increasing their opportunity for education.
Water and Infrastructure
Many water infrastructure systems built are composed of unsustainable materials causing problems with current infrastructure function. The costs of these problems have grown because of the lack of action to fix the problems. The aging pipes allow hundreds of billions of gallons of wastewater to flow into waterways, deeply threatening human health. In the United States alone, around seven billion gallons of water are lost every day (Terrero et al. 2013). Infrastructure is inefficient and leads to a lack of water because of the quantities wasted and lost. The large numbers of overflows from sewage systems has led to 10 billion gallons of untreated wastewater ending up in the United States’ surface water areas.
The costs of replacing and fixing all of the infrastructure in a country can be extremely expensive, trillions of dollars from the buildup of lack of action. There are cheaper alternatives to creating sustainable infrastructure to decrease the non-safe water being distributed into our safe water sources. Using Public-Private Partnership programs, or P3 programs, allows public agencies to create agreements with any private association. This private company will take care of the constructions, operations, and rehabilitation of the water infrastructure systems. This allows the private company to manage the finances of the project, to decrease prices for the public to pay (Woodside 1986). Filters exist to fix the problem of old pipes carrying pollution. The Berkey Water Filter removes any metal ions from the water, including fluoride and arsenic (“Alternative Technologies and Assessment for Water and Wastewater Utilities,” 2017). Eliminating this pollution creates a method of purifying the water, increasing the sustainability of water by removing pollution and creating new, safe water. These filters last many years, therefore increasing sustainable practice.
These irrigations systems of water purification use reclaimed wastewater; this purification level is not up to a standard of safe-to-drink (Lowrie et al. 2014). In order to be deemed safe-to-drink, water must be analyzed for numerous contaminants. Regulations include treatment for 81 MCLs, for inorganics and organics, 6 MCLs for microbial organisms, 4 radionuclide MCLS, filtration and disinfection, and treatment for lead, copper, acrylamide, and epichlorohydrin. These treatment requirements are protecting human health by ensuring the safest drinking water (Cotruvo 2012). Risk still exists for contamination requiring constant technological development to minimize exposure. To wisely use funding, regulations dealing with low-risk contaminants should be eliminated, priority needs to be made with the most risk situations, local action should be taken, and infrastructure needs to be cleared of contaminants (Cotruvo 2012).
Infrastructure that is old and contaminated can lead to the distribution of unsafe drinking water. Focusing on small systems should be prioritized instead of the large-scale systems that are costly and not effective. A small system is the green infrastructure (Henrie 2008). This is a technique of replicating the natural water cycle to clean storm water and reduce its runoff. Because the actions taken are replicating nature, they are both cost-effective and sustainable (Henrie 2008). Examples of green infrastructure are green roofs, which involve extending a roof to include waterproofing, root repellents, filters, draining, and areas of growth for plants. This green roof idea is almost creating a space of nature, as it should come about naturally without interference from pollution. Another method of green infrastructure is planting trees. Something so simple yet effective as trees collect water and reduce runoff. Lastly creating porous pavements to allow water to go through and into the ground below that requires water to strive (Spicer 2010). These simple, sustainable methods of infrastructure create a world of difference in conservation and smarter use of water. Aside from green infrastructure, a focus needs to be put on protection the sources of freshwater. If we focus on methods to protect and increase these sources, we can save money on operating systems of treatment and on large infrastructure. The last small-scale method that makes large-scale difference is decentralizing wastewater. This involves small septic systems to treat and disperse wastewater. It takes small amounts of the wastewater to different places away from domestic homes and commercial buildings. This decentralization prevents wastewater overflow, reducing risk of health damage (Santora and Wilson 2008). These small-scale solutions are cost-effective, and their impacts reduce many of the larger scale problems. These all contribute to sustainability of the infrastructure, creating sustainability of the water involved. If steps are not made, developed countries will continue to waste money attempting to delay system decay, and developing countries will never be able to attain infrastructure that could improve potability and sanitation.
Water scarcity is a significant issue globally; however, its impact is disproportionately felt between developed and developing countries. Developing countries battle with the problems of inefficient overuse of water in agriculture, limited supply of potable water, and insufficient resources to enable proper sanitation. The latter leads to millions of deaths annually from preventable bacterial and viral infections, primarily in infants.
The pricing of water has promoted its overuse. In many areas around the world, water is provided free of charge; in the majority of the remaining, the price is negligible. Arguably, the perceived cheapness of water has led to both its overuse both in direct human consumption and in the production sectors. Externalities related to agriculture are placing pressure on water resources. Crop yield is protected by herbicide ad pesticide use, both of which impact groundwater, contaminating its potability and potentially contaminating the waster for other uses as well. Animal agriculture impacts water through the production of feed, which is water intensive, as well as direct animal consumption.
There are present technologies in use and being developed to address the water shortage, and these include drip irrigation to desalinization to experimental cloud seeding. SDG 6 is dedicated to water and sanitation and is also connected to poverty eradication, the central theme of the SDGs. By addressing water in the context of a fundamental human right, the SDGs elevate the responsibility of providing access to water to the global forum. This latter attribution is a next step in the history of water.
- Alternative Technologies and Assessment for Water and Wastewater Utilities (2017) EPA, Environmental Protection Agency, 19 Jan 2017. www.epa.gov/sustainable-water-infrastructure/alternative-technologies-and-assessment-water-and-wastewater
- Atkinson K (1979) Trickle irrigation – a new technology in irrigated agriculture. Geography 64(3):219–221Google Scholar
- Brouwer C, Heibloem M (n.d.) Crop water needs. International Rice Commission Newsletter, vol 48, FAO of the UN. Retrieved from www.fao.org/3/S2022E/s2022e02.htm
- Diekmann F, Polacek K (2013) Organic farming: a research guide. Ref User Serv Q 52(3):197–204Google Scholar
- Global Affairs Canada (2017) Water in developing countries. GAC, 26 July 2017. Retrieved from international. https://www.cdc.gov/healthywater/global/index.html
- Global WASH Fast Facts | Global Water, Sanitation and Hygiene | Healthy Water | CDC. Centers for Disease Control and Prevention, Centers for Disease Control and Prevention. www.cdc.gov/healthywater/global/wash_statistics.html
- Gurian-Sherman D (2012) High and dry: why genetic engineering is not solving agriculture’s drought problem in a thirsty world. Union of Concerned Scientists, Massachusetts, USA, pp 1–5, RepGoogle Scholar
- Henrie M (2008) The green infrastructure action strategy. Water Resour IMPACT 10(2):17–19Google Scholar
- Houser T, Hsiang S, Kopp R, Larsen K, Delgado M, Jina A, … Steyer T (2015) Agriculture. In: Economic risks of climate change: an American prospectus. Columbia University Press, New York, pp 51–66Google Scholar
- Lawson R, Lyman J (2007) A Marshall plan for energy, water and agriculture in developing countries. Atlantic Council, Washington DC, USA pp 1–3, RepGoogle Scholar
- Mercy For Animals (20 Mar 2018). Retrieved from mercyforanimals.org/lambs-are-gentle-and-kind-so-why-the-heck
- Ravnborg H, Larsen R, Vilsen J Funder M (2013) Environmental Governance And Development Cooperation: Achievements and Challenges. Danish Institute for International Studies, København, Denmark, pp 5–7, RepGoogle Scholar
- Schutt A. Desalinization. Water encyclopedia. www.waterencyclopedia.com/Da-En/Desalinization.html
- Solar-Powered Water Pumps (n.d.) Practical action practicalaction.org/pumping-water-by-solar-power
- Spicer S (2010) US EPA begins permeable-pavement research. Water Environ Technol 22(3):19–25Google Scholar
- United Nations (2018) Goal 6: Sustainable development knowledge platform. Retrieved from sustainabledevelopment.un.org/sdg6
- United Nations (n.d.-a) MDG, water, sanitation, financing, gender, IWRM, human right, transboundary, cities, quality, food security, FAO, BKM, World Water Day. Retrieved from http://www.un.org/waterforlifedecade/food_security.shtml
- United Nations (n.d.-b) Water. Retrieved from www.un.org/en/sections/issues-depth/water/
- United Nations (n.d.-c) About the Sustainable Development Goals. Retrieved from https://www.un.org/sustainabledevelopment/sustainable-development-goals/
- Ward D (2019) Water requirements of livestock. Soil erosion causes and effects. Retrieved from www.omafra.gov.on.ca/english/engineer/facts/07-023.htm
- Water (n.d.) Weltagrarbericht. Retrieved from www.globalagriculture.org/report-topics/water.html
- Water, Sanitation and Hygiene (n.d.) UN-Water, www.unwater.org/water-facts/water-sanitation-and-hygiene/
- Water: How Much Should You Drink Every Day? (2017) Mayo Clinic, Mayo Foundation for Medical Education and Research. Retrieved from www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256
- Weil S (2013) How does water use in the United States compare to that in Africa. African Wildlife Foundation. Retrieved from https://www.awf.org/blog/how-does-water-use-united-states-compare-africa
- Yoneda T (1980) Wastewater treatment plants and policies of Kyoto. J Water Pollut Control Fed 52(5):978–984Google Scholar
- Zellmer S (2012) Wilderness, water, and climate change. Environ Law 42(1):313–374Google Scholar