Water Cycle Water Cycle


Water moves in an endless cycle from the sea and land to the atmosphere and back again. The sun's energy converts water from lakes, oceans, rivers and the surface layers of soil into water vapour. This process is called evaporation. Plants also add water vapour through transpiration. The water vapour rises into the atmosphere and condenses into clouds and it then precipitates and falls back to the land or sea as rain, sleet, hail or snow.

Most of the rain that falls on land either soaks into the soil in a process called infiltration or runs off the land surface into rivers, lakes and eventually out to sea. A dam can catch the intermittent flood flows that run off the catchment and store it for use during dry periods.


On earth most of the water exists in its liquid state as salty water in the oceans with lesser quantities of fresh water in lakes, rivers and clouds. For water to exist as a liquid, the temperature must be between 0°C and 100°C, at normal atmospheric pressure.

Note that water was used as the baseline for the Celsius scale: 0°C is the temperature at which water freezes and 100°C is the level at which water boils (at sea level).

Pure water is colourless, odourless and tasteless. The blue ocean colour you see is actually reflections from the sky.

Water has a very high surface tension. In other words it is elastic and sticky and tends to clump together in drops rather than spread out in a thin film. Surface tension is responsible for capillary action and this allows water (and dissolved substances) to move through the roots of plants and through the tiny blood vessels in our bodies.


As water cools it becomes denser, reaching maximum density at about 4 degrees Celsius. As it cools further it expands - below zero degrees Celsius water becomes a solid – ice. It is this property of water that allows ice to float on the surface of lakes and other water bodies and allows aquatic life to continue to survive in the liquid water underneath during winter.


Water as a gas is colourless and odourless. A fog you might see on a cold morning or the vapour above boiling water is a mist of liquid droplets. Steam is the invisible gas which is just on top of boiling water and below the visible mist. Pure steam exists at temperatures above 100°C.

Condensation is when water droplets appear on the outside of a cold glass or on the inside of a window in winter. Condensation forms from water vapour in the air. In cold air, water vapour condenses faster than it evaporates. As a result, when warm air touches the outside of a cold glass the air next to the glass becomes chilled and some of the water in that air turns from water vapour to tiny liquid water droplets. Rain is produced by water vapour evaporating from the earth which then condenses in the sky


Water can dissolve many substances and is known as the universal solvent. It carries many dissolved materials in its flow and it can act to clean and dilute wastes. Because water is so good at dissolving substances pure water is rarely found in nature. Streams and lakes can often look green or brown because of the mud or organic matter that has been dissolved in the water.

Because water can store a large amount of heat without a big change in its temperature, large bodies of water like lakes change temperature slowly. Animals and plants that live in the water are then protected from rapid temperature changes.

It also takes large amounts of heat to make air evaporate or turn to vapour. As water molecules are heated they move more quickly. The hottest water molecules move fast enough so that the strong bonds that hold the water molecules together are broken and evaporation occurs. As evaporation occurs, energy is released which has a cooling effect on the water molecules left . These properties of water, to buffer temperature fluctuations, are very important in regulating Earth's climate.

Because water is so effective at buffering temperature fluctuations, it is used as a coolant in things like car radiators. It takes almost nine times as much heat energy to increase the temperature of water by 1°C than it does to increase the temperature of the same weight of sand by 1°C.


Without water we would not be able to live. It makes up two-thirds of our body and we use it in so many ways: for drinking, watering, gardening, washing, for removing our wastes and for recreational activities.

A person can live approximately one month without food but only about a week without water. Water is the main ingredient in the fluids within our bodies. Water cools our bodies, lubricates it, carries nutrients through it and removes our wastes. Our blood is made up of around 85 per cent water and 75 per cent of the weight of our brain is water.


Where does the water in Lake Awoonga come from?

Run-off water from the nearby hills and mountains flows down into the Boyne River which eventually feeds into Lake Awoonga. The catchment area contributing to the lake is 2, 230 square kilometres and is surrounded by the Boyne, Dawes and Many Peaks Ranges.

What area does the catchment service?

The Gladstone Area Water Board (GAWB) provides water to Gladstone, Calliope, Boyne Island, Tannum Sands, Benaraby and Mt Larcom. GAWB also supplies water to CS Energy - Callide Power Station at Biloela and various industries in the region.

What is the highest level the water in Lake Awoonga has reached?

GAWB had raised the dam to 40m above sea level in 2002 and the drought that had commenced in 1996/97 eventually broke in February 2003 with 600mm of rain falling mainly over four days from a rain depression resulting from cyclone Beni. Further rainfall and inflows to Lake Awoonga on 18 March 2004 raised the water level to 36.94m above sea level, which was 75.63% of capacity.

Throughout November and December 2010, steady rainfall resulted in a total of 773mm of recorded rainfall and combined with inflows, the water level reached 43.8m (137.06% capacity).

An extreme rainfall event in late January of 2013 associated with ex-Tropical Cyclone Oswald led to record inflows with a peak level of 48.30m and then held approximately 1,500GL (193% of capacity).

What is the lowest level Lake Awoonga has reached?

After the dam was raised to 40m in 2002, the region was still in the grips of a severe drought. In April 2002 GAWB implemented the Drought Management Plan which required restrictions on water consumption. Before rain from Cyclone Beni relieved the drought levels in February 2003, Lake Awoonga reached a level of 20.84m above sea level which was 7.44% of capacity or 57,803 megalitres (a megalitre is one million litres).

How much water is consumed in the Gladstone region?

Information on total water provided by GAWB is contained in the Annual Report on our publications page.

For specific information on water supplied to households, you will need to contact your local council.

Historically, how has water consumption changed in the Gladstone region?

Since 1978, consumption of water in Gladstone has more than trebled. The increase in demand for water has come about because more industries have developed in the region, and because of the resulting increase in workforce/population.

How is water supplied to consumers?

The Awoonga Pump Station pumps water from Lake Awoonga at a rate of up to 3,000 litres per second. The water is carried to Gladstone through a series of pipelines, ranging in diameter from 700mm to 1440mm.

There are more than 200km of pipelines that carry water to various destinations in the region. This includes 147km of pipelines to carry raw or untreated water to customers and the water treatment plants. There is an additional 58km of pipelines that carry treated water to the Gladstone Regional Council and other industrial customers.

What are the storage facilities in the Gladstone region?

Awoonga Dam is the only permanent surface water storage in the Gladstone region. Awoonga dam is a 40m wall (above sea level) which was erected in two stages, to hold back water in the Boyne River.

The surface area of the lake at its full capacity of 40m is 6,750ha. It has a capacity of 777,000 megalitres. There are various reservoirs around the region which hold water on a temporary basis to balance pumping loads across the day.

GAWB owns three raw water reservoirs which hold a total of 116 megalitres of raw water (2 x 50,000 megalitres and 1 x 66,000 megalitres.)

What is a pump station?

A pump station is a building that holds the pumps that pushes the water through the pipelines.

What is a water treatment plant?

Water taken straight from Awoonga dam is not suitable to drink. It may contain pathogens, blue green algae and other contaminants; therefore, the water has to be treated to make it safe to drink. A drinking water treatment plant is a facility that cleans and disinfects water. GAWB owns and operates two drinking water treatment plants in the Gladstone City area, providing clean, safe drinking water for the region.