Water, after air perhaps, is the most precious resource available for use. Humans cannot survive much more than 5 days without drinking water, we need it to grow crops and feed animals, for cleaning and cooking, and for processing all man made goods and the provision of services. Although water is abundant on earth 96. 5% of the water is saline (Pennington & Cech, 2010) which is undrinkable and unsuitable for agriculture and industry.
A further 1. 7% is stored as frozen water. So when discussing water as a resource, in this case, it is the 1. % that exists as groundwater, in rivers, lakes, wetlands and soils that is being referred to, although not all of this is accessible. Currently the population of the world is over 6. 8 billion (U. S. Census Bureau, 2010) and population growth worldwide is about 1. 17% per year (Google, 2008). Life expectancy is increasing and coupled with these population factors are advancements in human society which are increasing our demands on water resources. In 2005 it was estimated that 48. 6% of the world’s population lived in urban areas (Encyclopedia of Earth, 2009) with this number constantly on the rise.
Urban water provision usually depends on inefficient infrastructure which is susceptible to leakage. People living in cities depend more on large scale farming and food processing industries that require large amounts of water and energy. Urban sprawl contributes to increased flooding and contamination of freshwater supplies because of impermeable surfaces which can negatively affect groundwater levels by decreasing the possibility of water seeping into the ground, increase evaporation of rainwater off bare ground and by polluting groundwater with urban waste (Pennington ; Cech, 2010).
The State of California has had its fair share of urbanisation related water issues whilst trying to provide for the citizens of Los Angeles, confessing to the depletion of local groundwater and draining of Lake Mono and Lake Owens (LADWP, 2010). But an ever growing population in an increasingly arid region means that state officials may have to go further to provide for their citizens, putting more farmers and ecology at risk. Further to urbanisation issues, there is the change towards water-profligate lifestyles for example higher demand for water intensive foods, such as meat and consumer goods.
Such increased agricultural and industrial demand needs to be fuelled by more energy, which is also a highly water intensive industry. Figure 1 Competing Water Uses Figure 1 above shows generally how the use of water is divided. Domestic use accounts for the smallest slice of the pie. This use of water is of upmost importance, but there are 13% of the world’s population without access to clean drinking water and 39% without adequate sanitation facilities (World Health Organisation, 2010).
Unclean water can lead to illnesses and an estimated 3. 75 million people, mostly children, die per year from water related illnesses such as diarrhoea, cholera and typhoid (World Health Organisation, 2008). Industry accounts for water usage in power plants, mining and refinery and manufacturing industries. Agriculture is the highest consumer of water, the majority being spent on irrigation and a smaller portion on aquaculture. Irrigation has allowed humans in the 21st century to intensify agriculture by expanding crop yield geographically and temporally (Hemson et al, 2008).
Irrigation is an important process in the provision of food but inefficiencies within the process also mean the technique can be very wasteful. An estimated 60% of water used for irrigation is lost through evaporation and seepage (Houghton, 2004). Heavy machinery used in agriculture compacts the soil, decreasing its water retention ability, leading to soil erosion and increased runoff. Chemical fertilizers are used to remedy this which in turn affects the soils water retention ability, increasing the dependency on irrigation and contributing to pollution.
All three uses of water specified can contribute to water pollution. Water pollution can come in three main categories; excess nutrients from sewage or soil erosion, pathogens from sewage and heavy metals and synthetic organic compounds from industry, mining and agriculture although other forms exist such as thermal pollution, radioactive substances and turbidity from sediment (Middleton, 2008). Water is in a continuous cycle so polluted water will not go away, so there is a need to protect and restore our water quality.
One big issue currently and historically facing humans is the uneven distribution of water resources. Although the worldwide hydrological cycle holds enough water several times over for human consumption, its distribution is not matched geographically or temporally to human needs (Jackson et al, 2001). Groundwater may not always be accessible or it may be physically or economically unviable to make use of some inaccessible lakes and rivers. Precipitation has a huge role to play in this also. As the world’s climate changes so with it changes the distribution of precipitation.
Regardless of any debate on the reasons, it is generally agreed that the earth is going through a warming process. Increased temperatures increase evaporation, with increased precipitation mainly in high latitudes and in the tropics, and decreased precipitation in the sub-tropics (IPCC, 2007). This could point to increased cases of flooding in some areas and drought in others. Another consequence of this is glacial retreat. One area of glaciers with negative mass balance is the Himalayas (WGMS, 2008), where glacial runoff supplies freshwater for drinking, agriculture and industry to millions of people in Asia.
As glaciers retreat, the amount of freshwater available during spring and summer times declines, having major repercussions on the availability of water long term. Tajikistan, a country with over 8000 glaciers providing freshwater to its rivers, is experiencing diminished water flow from the glaciers (Oxfam, 2010). Canadians in British Columbia have similar concerns as snowpacks, which usually recharge lakes and rivers, remained at low levels this winter (The Vancouver Sun, 2010).
Increasingly dams have been used as an answer for large scale domestic and irrigation supply, so much so that by the end of the 20th century at least 45,000 large dams had been built worldwide (World Commission on Dams, 2000). But dams by their nature block the flow of sediment and nutrients downstream, allowing trapped vegetation to rot, letting off methane gas and disrupting fish migration often having huge repercussions for communities downstream. Also it is not unusual for rivers to cross more than one border, and this may contribute to political tension.
Currently a drought in SE Asia has seen water levels of the Mekong river drop which is causing suspicion and anger to be directed at China, who are also experiencing drought, and have four dams built upstream (Probe International, 2010). Countries, such as China, with dams upstream are in a position to control the water supply to the countries downstream and this could become a more contentious issue as pressure increases on water resources worldwide. Desalinisation is a tactic currently being used in many countries as a way of addressing water shortages.
However desalinisation is an answer rather than a cure for a problem, using vast amounts of energy and potentially harming marine life. Typically an ideal way of managing our water resources is by implementing the slogan “Reduce, reuse and recycle”. Water is recycled in the hydrological cycle but reduction and reuse by all users would go far towards conservation. One of the problems with a water-profligate society is little or no thought is given to where water comes from, how much is used in production of goods and services and where is goes after use.
The term water-footprint was conceptualised by Hoekstra and Chapagain (2008) in an effort to quantify the total amount of freshwater used for the purpose of producing the goods and services consumed by a nation. Figure 1 below shows in red countries using over the global average of 1240mi?? /cap/yr (Waterfootprint. org, 2008) highlighting inequalities in water use. Figure 2 Average national water footprint per capita (mi?? /cap/yr) (Waterfootprint. org, 2008)
In effect awareness of water footprints can encourage people to strive to reduce their footprint, but it has its difficulties in that huge studies are needed to find this information because of the many stages that go into production processes. The water footprint website, http://www. waterfootprint. org, has begun to compare different food and beverage footprints, but this is very general with no differentiation as to where or who produced the good (i. e. beef reared on organic farms in UK vs. intensive farming in Brasil). More public awareness of this issue may place pressure on companies to publish and reduce their water footprint.
Another way of encouraging a reduction in use is water metering and charging thus putting value to water that is used. Currently in the UK only one in three homes has a water meter but it is claimed that in metered homes water use is 10-15% less than in non-metered homes (Environmental Agency, 2010). However as water should be a right and not a privilege, it would be ideal for a recommended allowance of water per person to be allocated of free or minimal charge, before full charges come in to effect, so those who consume excessively can be charged appropriately.
Ecosystem services provided by wetlands and forests should not be underestimated. Wetlands control flooding, filter pollutants and recharge purified groundwater and woodlands provide groundwater recharge and reduce sedimentation. Both are also important as wildlife habitats and wetlands can provide good fishing grounds for locals cutting back on a reliance on farmed fish industries. Protection of our ecosystems is an important part of water resource management and their importance need to be considered by planning authorities and governments.
At present the value of peatlands have begin to be recognised, not only for the water resource services, in fact mainly for the carbon capture services but any wetlands restoration project, no matter the reason, is a step in the right direction (BBC News, 2010 and IUCN, 2009). Project Blue Alternative was developed by hydrologist Michal Kravcik in response a proposed dam in Slovakia (Michal Kravcik, 1999) with the alternative creation of micro basins, and small weirs and dams on rivers and streams instead of huge dams.
This project managed the water more efficiently at 20% of the cost while protecting ecosystems and the livelihoods of the people. Further on from this is importance placed on restoration of watersheds by creating natural areas for collection (People and Water, 2010). On a global level this capturing could begin at coastal areas where rainclouds blow over easily, and as the ground recharges becoming wet and cool, capturing could begin further inland (Blue Gold, 2008).
Implementing rainwater capture projects in urban areas would also reduce the strain on the drainage and piping systems. Rainwater captured can be used for all purposes, even drinking with the addition of UV filtration. The greatest inefficiency of all water use is in the agricultural sector, and greater management and technological advancement is needed in this area. In the past water resources for farming was managed more efficiently, but this has been pushed out by mass irrigation.
Precision agriculture consists of using sensing equipment such as GPS and historical maps to deliver inputs such as water and fertilizer where and when needed by the crop (Bongiovanni ; Lowenberg-Deboer, 2004). Drip-fed irrigation is the most efficient in that it delivers water to the plant roots rather than spraying it into the air, thus reducing evaporation and enhancing soil quality (Black ; King, 2009). Hydroponics is a soil-less style of growing which can also be water efficient and recently has been coupled with aquaculture.
Aquaponics, as it is termed, uses “nutrient rich effluent from fish tanks to fertigate hydroponic production beds” (Aquaponics, 2006). Projects like this increase water use efficiency and a greater realisation of the pressures on our water resources will see projects like this being rewarded for forward thinking and water stewardship. All in all we need to realise the value of our freshwater system and understand the inefficiencies and flaws in our use of it which has created reason for concern. Without this vital understanding our planet may be pushed to its extreme.