Techniques of Water Conservation
Techniques of Water Conservation
- Water conservation includes all the policies and activities made to sustainably manage the natural resource of freshwater in order to meet the current and future human demand.
- Water conservation has the following objectives:
- Ensuring the availability of water for future generations, where the withdrawal of freshwater from an ecosystem does not exceed its natural replacement rate.
- Energy conservation as water pumping, delivery and wastewater treatment facilities consume a significant amount of energy. In some regions of the world, over 15% of total electricity consumption is devoted to water management.
- Habitat conservation, where minimising human water use helps preserve freshwater habitats for wildlife.
Techniques of Water Conservation
- The harvesting of rainwater simply involves the collection and storage of rainwater for later use.
- There are two ways of harvesting rainwater:
Surface runoff harvesting
- Rainwater flows away as surface runoff. This runoff could be controlled and used for recharging aquifers by adopting appropriate methods such as check dams.
- Check dams are barriers to stop the running water and are used to accumulate water at a place.
Rooftop rainwater harvesting
- In this system, rainwater is collected from the building roof and stored in tank or diverted into recharge wells.
- Both surface runoff and rooftop rainwater harvesting can be used to recharge underground water or to pump water into reservoirs.
Conservation of Groundwater Resources
- Another strategy in water conservation is to protect groundwater resources.
- When precipitation occurs, some infiltrates the soil and goes underground. Water in this saturation zone is called groundwater.
- Groundwater can be conserved by adopting the following strategies:
- Some examples of potential sources of groundwater contamination include uncontrolled hazardous waste, landfills, atmospheric contaminants, chemicals and road salts.
- Contamination of groundwater decreases its replenishment and even makes it unusable.
- An additional strategy to water conservation is practicing sustainable methods of utilising groundwater resources.
- Groundwater flows due to gravity and eventually discharges into streams. Excess pumping of groundwater leads to a decrease in groundwater levels and if continued, it can exhaust the resource.
- Ground and surface waters are connected and overuse of groundwater can reduce and, in extreme examples, diminish the water supply of lakes, rivers and streams.
- The ‘vadose zone’, also termed, ‘the unsaturated zone’, is the part of Earth between the land surface and the highest level of the groundwater (‘vadose’ literally means ‘shallow’).
Household and Industrial Applications
During household and industrial usage, water-saving can be undertaken by any of the following means:
- Low-flow shower heads: These are sometimes called energy-efficient shower heads as they also use less energy.
- Low-flush toilets and composting toilets: These can save large amount of water as conventional western toilets use large volume of water.
- Faucet aerators: These break water flow into fine droplets to maintain ‘wetting effectiveness’ while using less water. An additional benefit is that they reduce splashing while washing hands and dishes.
- Raw water flushing toilets: These toilets use sea water or non-purified water.
- Wastewater reuse or recycling systems allow the use of the following:
- Reuse of grey water for flushing toilets or watering gardens,
- Recycling of wastewater through purification at a water treatment plant.
- Rainwater harvesting.
- High-efficiency clothes washers.
- Weather-based irrigation controllers.
- Garden hose nozzles that shut off water when it is not being used, instead of letting a hose run.
- An automatic faucet: This is a faucet equipped with a proximity sensor and mechanism that opens its valve to allow water to flow in response to the presence of a hand or hands in close proximity. Techniques of Water Conservation
- For crop irrigation, optimal water efficiency means minimising losses due to evaporation, runoff or subsurface drainage while maximising production.
- Flood irrigation, the oldest and most common type, is often very uneven in distribution, as parts of a field may receive excess water in order to deliver sufficient quantities to other parts.
- Overhead irrigation, using centre-pivot or lateral-moving sprinklers, has the potential for a much more equal and controlled distribution pattern.
- Drip irrigation is the most expensive and least-used type, but offers the ability to deliver water to plant roots with minimal losses.
- However, drip irrigation is increasingly affordable, especially for the home gardener and in light of rising water rates.
- There are also cheap effective methods similar to drip irrigation such as the use of soaking hoses that can even be submerged in the growing medium to eliminate evaporation.
- As changing irrigation systems can be a costly undertaking, conservation efforts often concentrate on maximising the efficiency of the existing system.
- This may include chiseling compacted soils, creating furrow dikes to prevent runoff, and using soil moisture and rainfall sensors to optimise irrigation schedules.
- Improved soil organic matter from the use of green manures, mulching and recycling of crop residues and animal manure increase the water holding capacity of soils and their ability to absorb water during torrential rains, which is a way to optimise the use of rainfall and irrigation during dry periods in the season.
- Water shortage has become an increasingly difficult problem to manage. More than 40% of the world’s population lives in a region, where the demand for water exceeds its supply.
- The imbalance between supply and demand, along with persisting issues such as climate change and exponential population growth, has made water reuse a necessary method for conserving water. Techniques of Water Conservation
- There are a variety of methods used in the treatment of wastewater to ensure that it is safe to be used for irrigation of food crops and/ or drinking water.
- This requires more energy than the desalination of freshwater. Despite this, many sea water desalination plants have been built in response to water shortages around the world.
- This makes it necessary to evaluate the impacts of sea water desalination and to find ways to improve desalination technology.
- Current research involves the use of experiments to determine the most effective and least energy intensive methods of desalination.
- This is another method used to treat water. Sand filtration is very effective in removing protozoa and bacteria, but struggles in removing viruses.
- Large-scale sand filtration facilities also require large surface areas to accommodate them. Techniques of Water Conservation
- The removal of pathogens from recycled water is of high priority because wastewater always contains pathogens capable of infecting humans.
- The levels of pathogenic viruses have to be reduced to a certain level so that recycled water does not pose a threat to human populations.
- Further research is necessary to determine more accurate methods of assessing the level of pathogenic viruses in treated wastewater.