Liquid Harvest

Clean, fresh water; the liquid of life!

The human body contains more than seventy percent water, and it requires around two litres of water daily. We become thirsty with a drop of just a half-percent in our body’s water content. A drop of five percent and we develop a light fever. Our glands stop producing saliva and our skin begins to turn blue with an eight percent drop. When our water content drops by ten percent, we can no longer walk, and death is imminent with a twelve percent drop (Lanz, The Greenpeace Book of Water).

Modern living uses far more water than two litres, per person each day. Australian households use an average of 500 litres of water daily; that is about 200,000 litres per year. However, when considering our hidden water consumption, the real annual water consumption soars to one million litres, per person.

Most of our water usage hides in what we consume, for example, the food we eat, the clothes we wear, and other items we buy. ‘Virtual water content’ refers to the amount water used during the entire process of growing, making, packaging, and transporting a product to the end user.

The following statistics on ‘virtual water content’ of a product are from the Water Footprint Organisation’s website (www.waterfootprint.org).

• 1 kilogram of beef 16 000 litres

• 1 cup of coffee 140 litres

• 1 kilogram of rice 3000 litres

• 1 (250 g) cotton t-shirt 2000 litres

• 1 microchip 200 litres

Since the beginning of the twentieth century, water consumption has increased ten-fold. Predictions are for serious worldwide shortages of fresh water by 2020. Already, more than one third of the world does not have access to clean drinking water, leading to disease and even death. Water shortages cause crop failure, leading to malnutrition and starvation in developing countries.

Fresh water accounts for only three percent of all water on Earth, the majority of which is inaccessible, confined in the atmosphere, soil, ice caps, or in aquifers.

Mother Nature ensures the availability of fresh water through recycling, that is, evaporation followed by rain. Technically, there should be the same amount of fresh water on Earth today as there was a million years ago, but human interference has disturbed the natural cycle. We extract more water than rainfall can replace, use it only once, contaminate it, then dump it, often into the sea.

The green movement warned of the impending water crisis for decades, but the soothsayers often accused them of scaremongering. Unfortunately, the majority listened to the soothsayers, our desire for an endless water supply affecting our judgement.

Australians are one of the biggest water users, per capita, in the world, yet we live on the driest inhabited continent. We also have the greatest variability of rainfall, with most falling in the tropical north, while vast areas are arid.

The picture for Earth is bleak, requiring immediate, ongoing action. A water-saving showerhead, dual-flush toilet, and water-efficient washing machine will not be enough to solve the water crisis. Not even a water tank in every backyard. Although these things will help, large-scale change is needed.

There are numerous solutions to harvesting, using, and reusing water, but each has complex considerations. Previously, quality, adequate supplies and cost, were the important issues. Now, it is imperative to include the ecological implications of human water usage.

Dams represent the human desire to control nature, allowing us to regulate and exploit a valuable resource. Dams not only store a town’s water supply, but also are vital in the hydro-electricity process. Electricity cannot be stored, but water can, thus helping power providers to meet fluctuating demands. Almost no major rivers across Europe and America remain untouched.

Control of the rivers has completely reversed natural seasonal flows, depriving vegetation of its normal supply, affecting biodiversity, and eradicating native aquatic species. Many major rivers, such as the Colorado, rarely complete their natural journey, reducing water levels in adjoining, dependent water systems.

Dams also deprive humans living downstream of the water supply. Israel and its Arab neighbours are battling over Golan Heights, while a scheme by Turkey to dam the Tigris and Euphrates threatens water supplies to Syria and Iraq.

More dams don’t mean more water if there’s a shortage of rain over a long period, as the numerous near-empty dams across drought-stricken Australia demonstrate. A twenty percent drop in rainfall reduces water catchment by fifty percent.

Environmentalists are now calling for ‘an end to the dam age’, due to destruction of natural river systems. Instead of huge dams stopping river flow, river water can be harvested by diverting part of the flow, or the current used to drive electricity. This will reduce the negative impact upon the ecology of river systems.

Desalination reinforces single water usage, and contributes to greenhouse emissions through the large amounts of electricity required.

There are restrictions, not only to seaside locations, but also by access to power. The process of desalination kills marine life sucked into the meshed inlet pipes. Highly saline, reject water causes oxygen deficiencies in marine life, unless the nearby rivers flush the area with fresh water frequently. Chemicals used for disinfection of the water also harm marine ecosystems, if disposed of incorrectly.

In the sixty years since the discovery of reverse osmosis, required for desalination, technology has hardly progressed, according to John Archer in Twenty Thirst Century. One of the most up-to-date desalination plants, located at Tampa Bay in Florida, took seven years before it operated at full capacity, due to a series of equipment malfunctions and environmental issues.

Recycling sewage currently provides one of the best long-term, economic and environmentally sustainable possibilities.

Recycled water comes in two forms, potable and non-potable. Potable water is usable for everything, including drinking, cooking and bathing, while non-potable is restricted to watering, toilet flushing, clothes washing, and some industrial uses.

Non-potable water is the more expensive option, because it requires a dual reticulation system for every household and industry accessing it, a logistic and economical nightmare for established areas. However, non-potable water is feasible for new urban development. The NSW Government announced the development of non-potable reuse schemes for new urban release areas, and other governments have similar plans.

A recycling plant, planned for Kurnell, will provide non-potable, recycled sewage water to local industries, saving six million litres of drinking water daily. It seems we might be heading in the right direction, although the benefits will not be significant for more than a decade.

Australians are not ready to accept potable recycled water, yet this is the cheapest option because the recycled water is piped directly to storage facilities, then delivered to our homes via the existing pipes. Bacterial content from faeces is the main concern, as are the toxic chemicals entering sewerage systems from our homes and industries.

However, the public is largely unaware that treated sewage is already in some drinking supplies. Inland treatment plants return the treated sewage to the river system, which people living downstream use.

Stormwater harvesting utilises water that would otherwise be wasted. In developed urban areas, rainwater, which once returned to the water table through absorption, flows into stormwater systems, and often dumped into the ocean in coastal areas.

The Waterproofing Northern Adelaide project, will capture 17 gigalitres of stormwater, per year, cleanse it in engineered wetlands, and then deposit it in the Northern Adelaide Plains aquifer for storage and reuse.

North Sydney Council and Cammeray Golf Club will harvest 90 million litres of stormwater annually, by collecting run-off from the Warringah Expressway and the surrounding urban catchment. After treatment, the water will be used for the golf course, nearby soccer fields, and eventually extended to other parks.

Groundwater is an invisible source of water, and its invisibility makes it the hardest to understand in ecological terms, and the most difficult to monitor. Some groundwater recharges quickly, but less porous ones may take a thousand years.

While many countries report national extraction rates below recharge rates, some regions, within a country, are in over draft, for example in India. Over-extraction of groundwater threatens the remaining water quality, through increased chemical concentrations, such as naturally occurring fluoride, arsenic and salt. There have been reports of arsenic poisoning in many countries, such as Mexico, Taiwan, Japan, and Bangladesh.

Pollution is also a problem for groundwater supplies. Domestic and industrial pollutants seep through the soil and into the groundwater, which then passes into our creeks, rivers and eventually into our drinking water.

Pressure loss, caused by unused, leaking bores, currently threatens Australia’s Great Artesian Basin, which is the only reliable water source for a large part of the arid inland. The Federal Government plans to close off unused bores over the next ten years.

Land clearing, unsustainable agricultural, global warming and droughts have also contributed to water shortages, as has government inaction and our demand for an endless supply of freshwater.

Each of us must accept responsibility for our water problems. Implementing numerous water harvesting and water saving strategies may help to provide adequate, long-term supply of freshwater, but our best hope lies within our attitude towards water. Humans need to change from thinking that water is theirs to use as desired, with disregard for the consequences.

We need to worship and treasure water for the invaluable resource it is, for without it, there is no life!