[via : PetroZine Newsletter]
Water is life ! It is a precondition for human, animal and plant life as well as an indispensable resource for the economy. Water also plays a fundamental role in the climate regulation cycle.
The Pacific Ocean covers half the globe - an area big enough to fit all the continents. In fact, 75% of the world is covered by water, so although we call our planet ‘Earth’, perhaps we should really have named it ‘Water’! Most of the water on Earth is salty. Only about 3% is fresh water and some of this is frozen in glaciers and icebergs. Water is essential for the survival of living creatures, but there is a relatively small amount to be shared around - and that makes it very precious. We need to get better at looking after this valuable resource.
What do you know about water conservation and water pollution? Read about Water and test your knowledge here!
Awareness on water conservation
Water is a precious resource in our environment. Growing populations and ongoing droughts are squeezing our water resources dry, causing natural habitat degradation and impacting our everyday use of water.
Why save water?
Of all the water in the world, only 3% is fresh. Less than one third of 1% of this fresh water is available for human use. The rest is frozen in glaciers or polar ice caps, or is deep within the earth, beyond our reach.
To put it another way, if 100 litres represents the world’s water, about half a tablespoon of it is fresh water available for our use.
The global water situation
remember that our local water supplies are part of a bigger global water cycle
Fresh water is essential to our existence - it allows us to produce food, manufacture goods and sustain our health. It is also an essential part of the natural environment which supports all human, plant and animal life.
Global water consumption has risen almost tenfold since 1900, in many parts of the world, and they are now reaching the limits of their supply. World population is expected to increase by 45% in the next thirty years, whilst freshwater runoff is expected to increase by 10%. UNESCO has predicted that by 2020 water shortage will be a serious worldwide problem.
One third of the world’s population is already facing problems due to both water shortage and poor drinking water quality. Effects include massive outbreaks of disease, malnourishment and crop failure. In addition, excessive use of water has seen the degradation of the environment costing the world billions of dollars.
Embodied water
What is embodied water?
When thinking about how much water you use you probably think about how much water you use from the taps or tanks around the house and garden, and perhaps even the amount you use at work. But have you ever thought about the amount of water used to produce some of those items you take for granted in your life - food, clothing, furniture, building materials, etc.?
There is often a high amount of ‘embodied water’ associated with many items we use or consume on an everyday basis. This is the amount of water used during the growing, processing and transportation of the goods we use or consume, or the services we use.
As an example, here are some statistics showing the amount of water used to produce some everyday items.
It takes…
- 140L of fresh water to produce 1 cup of coffee
- 1,000L of fresh water to produce 1L of milk
- 1,350L of fresh water to produce 1kg of wheat
- 3,000L of fresh water to produce 1kg of rice, and
- 16,000L of fresh water to produce 1kg of beef
The impacts of consumption
There are many hidden effects of excessive water consumption, including:
Building more dams. This has severe environmental effects such as destruction of wilderness, creation of greenhouse gases from rotting vegetation, altered stream flows and degraded ecological health. It’s also very costly!
Maintaining other infrastructure for water supply and use. This includes costly upgrades and maintenance of pipes, sewers and treatment facilities.
Erosion, salinity and desertification. Water consumption for agriculture alters the natural water cycle in many areas of Australia. This degrades production areas and intensifies other environmental problems such as land clearing and desertification.
Degradation of water bodies. Many of our rivers, wetlands and bays are degraded. This is partly due to the high levels of water extracted, as well as polluted surface runoff and storm water flushed into them.
It’s time to take action
let’s not play the blame game, each of us needs to take responsibility and take action at home, at work and at play!
As populations increase across the rest of the world, demand for water will also increase. If we don’t reduce each individual’s demand for water (both directly and through embodied water) the water situation will become dire
Concepts and Techniques on water conservation
Rain Water Harvesting
The rainwater that falls on the rooftops can be harvested for groundwater recharge using appropriate techniques. This method may be applied for the roofs of existing houses/buildings as well as those to be constructed in future.
It is estimated that a total of 2 MCM of water can be utilized for groundwater recharge at a cost of Rs.18.92 crores.
Lakes and Depressions
Lakes have often been misused for dumping of solid waste and sewage disposal. Water quality can be improved by replicating the principles of wetlands by the introduction of aquatic plants and fish in a systematic manner. Unique phenomenon of algae, bacteria symbiosis reduces the BOD (Biochemical Oxygen Demand). The fish population acts as an ecological manipulator by grazing on the algal population.
The storage capacity can be increased by desilting and widening. By desilting and deepening the lakes with the assistance of draglines machines, the lakes would need to be linked up with storm water runoff in the vicinity to augment the inflow.
This measure improves the quantity of groundwater recharge as well as the quality of available groundwater.
Floodplain Reservoirs
In this method we creates a recharge basin and reservoirs on the flood plains by scooping out earth from the flood plains at appropriate locations and letting these reservoirs to be filled up by the expanded monsoon season flow of the river.
The Yamuna flood plain comprising of 97 sq.km. of area in Delhi offers a good scope for development of groundwater resources subsequent to the storage of monsoon waters on the flood plain itself. Out of 580 MCM of monsoon season flow allocated to Delhi about 280 MCM goes unutilized due to lack of storages.
Quarry Reservoirs
Abandoned quarries are available in the vicinity of urban areas. With some modification of their catchment area and/or linkage with some nearby channels these can be used to store water, which would otherwise run-off. Depth and width of these quarries can be increased where the volume of runoff waters can be calculated to be in excess of present storage capacity.
Historical Water Bodies
Many ancient reservoirs have been disused due to change of catchment characteristics or due to destruction of feeding channel. These baolis/reservoirs can be reused as small recharge points. Major gains can be made only from the large reservoirs.
Paleo-Channels
These are abandoned course of rivers or streams and can be served as excellent ground water storage and recharge locations. Division of some of the monsoon flows into these channels greatly replenishes the declining water table for subsequent use.
Check Dams
In the regional topography several small or large check dams are possible and may be created not so much for surface withdrawal but for recharging the falling ground water table. There are number of micro watersheds present in Delhi e.g. in the Ridge which provide excellent topographical formation to conserve monsoon runoff through simple recharge structures.
Village Ponds
The original purpose of village ponds was to give sustainability to adjacent wells and for cattle drinking, bathing, etc. As village are absorbed into urban areas with increasing reliance on tube wells, the ponds are becoming cesspools. These ponds can function as storage reservoirs and recharge areas subsequent to desiltation and improvement of their water quality. Following recommendations are given:
No sewage should be diverted to ponds in order to maintain their water quality.
No garbage dumping should be permitted.
Technique of in-situ improvement of water quality using aquatic plants and fishes can be introduced where necessary in order to avoid mosquito breeding.
Grass plantation should be carried out along the perimeter of ponds in the immediate sloping catchment.
Existing ponds are to be widened to the extent possible and deepened by 1.0m and nearby storm water drainage is to be used to fill up the additional capacity thus created.
Pond may be desilt and deepen with the assistance of draglines machines.
Ecoparks
This involves the creation of artificial wetlands using aquatic plant root zone system to treat sewage waters up to tertiary levels for recycling to the irrigation and horticultural sector and possibly some industrial estates.
The system utilizes the roots of certain type of plants to provide sub-striates for the growth of bacteria, which utilizes the nutrients present in the effluents, and for the transfer of oxygen. The plants commonly employed are duckweed, water hyacinth, pennwort, etc. The plants have to be harvested regularly and about 20 to 25% plants should be removed at each harvest. These plants have a root system of rhizomes, containing thick hollow air passages, from which fine hair roots hang down.
This root zone can support a very large population of aerobic microorganisms. Bacteria, dominate the microbial population, which is expected to degrade most of the simpler organic materials i.e. those contributing to BOD. The fungi and actinomycetes, although fewer in number, have a wider range of hydrolytic activities and are expected to degrade many of the large molecules that contribute to the COD.
The waste water encounters alternate aerobic and anaerobic microbial population which convert carbonaceous and to a lesser extent nitrogenous and phosphatic, contaminants in the water to less polluting materials. Further microorganisms can form biofilms around lower stems, which can then trap particles suspended in the wastewater by absorption.
It is expected to achieve an effluent quality of 5-10mg/l of suspended solids. A total of 495 MGD of recycled water can be made available for irrigation, horticulture and industrial needs and for domestic non-drinking supply.
We have no choice but to pay more attention to how we are using water, and how we may be wasting it. We must bridge the gap between our understanding of how important water is to our survival and what we can do to ensure that we have an adequate supply of clean water for years to come.
It’s time to be water efficient!
It is obvious that we cannot increase demands for water much more without detrimental effects to the environment, society and the economy.
It’s all too easy to blame someone else for the water situation – “if 70% of water is used for agriculture then that’s what we should target” – but it’s not that easy. We all depend on the food and resources that agriculture provides, and while there are definitely opportunities to increase water efficiency on the farm, the solution will take more than that.
We each share responsibility for the sustainable management of our water resources, which means using less water at home, in the workplace, at school, on holidays, on the farm, … everyone, everywhere, every time.
It’s time to become water efficient! This involves reassessing our relationship with water, and learning to use it more sparingly. On the most basic level, it requires a behavioural change, and assigning a value to water that truly reflects its worth.
We can also unlock economic benefits of being water efficient. There are many real world examples given in the case studies on this site.
Everybody has a responsibility to save water, if future generations are to enjoy a similar standard of living to the one we enjoy now. In fact, many of the impacts associated with water use are likely to have an effect on our own lives!
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