Sustainable Water Resources
Groundwater accounts for greater than 50% of global freshwater; thus, it is critical for potable water (Lozan et al, 2007). Groundwater can be a sustainable water supply source if the total amount of water entering, leaving, and being stored in the system is conserved. There are three main factors which determine the source and amount of water flowing through a groundwater system: precipitation, location of streams and other surface-water bodies, and evapotranspiration rate; it is thus not possible to generalize a sustainable withdrawal or pumping rate for groundwater (USGS, 1999). Unsustainable groundwater use results in water-level decline, reduced streamflow, and low water quality, jeopardizing the livelihood of effected communities. Various practices of sustainable groundwater supply include changing rates or spatial patterns of ground-water pumpage, increasing recharge to the ground-water system, decreasing discharge from the groundwater system, and changing the volume of groundwater in storage at different time scales (USGS, 1999). A long-term vision is necessary when extracting groundwater since the effects of its development can take years before becoming apparent. It is important to integrate groundwater supply within adequate land planning and sustainable urban drainage systems.
Collecting water from precipitation is one of the most sustainable sources of water supply since it has inherent barriers to the risk of over-exploitation found in surface and groundwater sources, and directly providesdrinking water quality. However, rainwater harvesting systems must be properly designed and maintained in order to collect water efficiently, prevent contamination and use sustainable treatment systems in case the water is contaminated. A number of drinking water treatments exist at point-of-use, each with advantages and disadvantages. These include solar treatment, boiling, using filters, chlorination, combined methods such asfiltration and chlorination, flocculation and chlorination. Although technically given the Earth’s surface and precipitation, rainwater harvesting can meet global water demand, the solution can most practically be a supplement to sustainable water supply systems given a level of uncertainty (especially with climate change), and competing land-use applications.
Reclaimed water, or water recycled from human use, can also be a sustainable source of water supply. It is an important solution to reduce stress on primary water resources such as surface and groundwater. There are both centralized and decentralized systems which include greywater recycling systems and the use of microporous membranes. Reclaimed water must be treated to provide the appropriate quality for a given application (irrigation, industry use, etc.). It is often most efficient to separate greywater from blackwater, thereby using the two water streams for different uses. Greywater comes from domestic activities such as washing, whereasblackwater contains human waste. The characteristics of the two wastestreams thus differ.
Desalination has the potential to provide an adequate water quantity to those regions that are freshwater poor, including small island states. However, the energy demands of reverse osmosis, a widely-used procedure used to remove salt from water, are a challenge to the adaptation of this technology as a sustainable one. The costs of desalination average around 0.81 USD per cubic meter compared to roughly 0.16 USD per cubic meter from other supply sources (USGS, 2010). If desalination can be provided with renewable energies and efficient technologies, the sustainable features of this supply source would increase. Currently, desalinationincreases operational costs because of the needed energy (and also carbon dioxide emissions); this in turn raises the cost of the final product. In addition, desalination plants can have negative impacts on marine life, and cause water pollution due to the chemicals used to treat water and the discharge of brine.
Packaged water is a 21st century phenomenon whereby mostly private companies provide potable water in a package for a cost. In some areas, packaged water is the only reliable source of safe drinking water. However, often in these same locations, the cost is prohibitively expensive for the local population to use in a sustainable manner. Packaged water is not considered an “improved drinking water source” when it is the only potable source available (UN, 2010). When sustainability metrics are used to access packaged water, it falls short in many situations of being a sustainable water supply. Economic costs, pollution associated with its manufacturing (plastic, energy, etc.) and transportation, as well as extra water use, makes packaged water an unsustainable water supply system for many regions and for many brands. It takes 3-4 liters of water to make less than 1 liter of bottled water (Pacific Institute, 2008).
Potable water requires some of the strictest standards of quality in terms of bacteriological and chemical pollutants. These standards are often governed by national governments; international recommendations can be found from the World Health Organization. Drinking water must be freshwater and should be free of pathogens and free of harmful chemicals.
Water in Industry
Water is used in just about every industry. Industrial water withdrawal represents 22% of total global water use (significant regional differences). Its use is notable for manufacturing, processing, washing, diluting, cooling, transporting substances, sanitation needs within a facility, incorporating water into a final product, etc. (USGS, 2010). The food, paper, chemicals, refined petroleum, and primary metal industries use large amounts of water (USGS, 2010). A sustainable water supply in industry involves limiting water use through efficient appliances and methods adapted to the particular industry. Rainwater harvesting on-site (including the creation of large pond-like structures), as well as recycling water in industrial processes, can provide a sustainable water supply for industry without straining municipal water supplies. Industry releases organic water pollutants, heavy metals, solvents, toxic sludge, and other wastes into water supply sources. Industry thus has a dual responsibility for internal sustainable water supply and the protection of external water supply sources.
Water in Agriculture
Agriculture uses the largest amount of freshwater on a global scale. It represents roughly 70% of all water withdrawal worldwide, with various regional differences. In the United States, for example, agriculture accounts for over 80% of water consumption (USDA, 2010). The productivity of irrigated land is approximately three times greater than that of rain-fed land (FAO, 2010). Thus, irrigation is an important factor for sustainable agriculture systems. In addition, global food production is expected to increase by 60% from 2000 to 2030, creating a 14% increase in water demand for irrigation (UN, 2005). Agriculture is also responsible for some of the surface and groundwater degradation because of run-off (chemical and erosion-based). It thus has a dual role in sustainable water supply: (1) using water efficiently for irrigation and (2) protecting surface and groundwater supply sources. Techniques for sustainable water supply in agriculture include organic farming practices which limit substances that would contaminate water, efficient water delivery, micro-irrigation systems, adapted water lifting technologies, zero tillage, rainwater harvesting, runoff farming, and drip irrigation (efficient method that allows water to drip slowly to plant roots by using pipes, valves, tubes and emitters).
Domestic Water Uses
The average household needs an estimated 20-50 liters or 5-10 galons of water per person per day, depending on various assumptions and practices (Gleick, 1996). Reducing water use through waterless toilets, water efficient appliances, and water quantity monitoring, is an important part of sustainability for domestic water supply. Efficient piping systems that are leak-free and well insulated provide a network that is reliable and help to limit water waste. The aforementioned potable water supply sources, with their sustainability features and sustainability challenges, are all relevant to other domestic uses. Since water quality standards are not as strict for household uses as for drinking, there is more flexibility when considering sustainable domestic water supply (including the potential for reclaimed water use).
A water supply system will only be sustainable if it promotes efficiencies in both the supply and the demand. Initiatives to meet demand for water supply will be sustainable if they prioritize measures to avoid water waste. Avoiding water wastage will contribute to reducing water consumption and, consequently, to delaying the need for new resources.
On the supply side, it is fundamental to enhance operation and maintenance capabilities of water utilities, reducing non-revenue water (NRW), leakages, and energy use, as well as improving the capacity of the workforce to understand and operate the system. It is also necessary to ensure cost-recovery through a fair tariff system and “intelligent” investment planning. In addition, all alternatives to increase the water supplymust be analysed considering the entire life cycle.
On the demand side, the adoption of water efficient technology can considerably reduce water consumption. Investments in less water intensive industrial processes and more efficient buildings lead to a more sustainable water supply. Concrete possibilities of economic savings, social benefits (such as the involvement of different sectors of society to reach a common objective, environmental awareness of the population, etc.) and a range of environmental gains make the adoption of water efficient technologies viable.
Sustainable water supply involves a sequence of combined actions and not isolated strategies. It depends on the individual’s willingness to save water, governmental regulations, changes in the building industry, industrial processes reformulation, land occupation, etc. The challenge is to create mechanisms of regulation, incentives and affordability to ensure the sustainability of the overall system of use. (https://www.iwapublishing.com/news/sustainability-water-supply)
- GFES owns and controls precious water resources in North America
- GFES has invested heavily in clean and agricultural water reserves
- GFES is continually working to utilize our water resources in a responsible manner.
- GFES water resources have been independently lab tested at 7.22 pH.
- GFES invests in clean and sustainable water packaging.