By building their own boats out of natural materials found near a river, children can explore and interact with rivers in a different way. The can use their boat to see the difference in speed of a river, to see where the current of the river is flowing - what obstacles are in the river.
It’s a fun way to also work out what materials can float.

We visited a river near us to have some fun. We wanted to see if the boats we had made could float.

We launched them. They started to float down the river

It seemed that everybodies boats were floating - we were pleased.

Some of us tried to hurry ours along - we had a bit of a race. We watched our boats to see if they could make their way around obstacles. Could they survive waterfalls? How far can they go?

Zack decided to put a little sign on his which asked that whoever might find it would let us know where they found it so we could track how far it had traveled and then maybe we could try and work out how it got there.

I wonder where Zack’s boat is now?

Go to our craft section to find out some ideas on how to make your own boat.

• A bit about rivers
• Importance of rivers
• Pollution of Rivers
• The Murray Darling River System

Imagine the storys that rivers carry with them. Stories of all the places they have flowed through. Rivers can start from a spring, a lake even from the melting of a glacier or from a high mountain top.

Most rivers flow on the surface and they always flow downwards.

Rivers that flow very quickly are called youthful and they flow deep rather than wide. A mature river is one that flows more slowly. The rivers with rapids and even waterfalls are used as a source of energy.

People have always lived near rivers, throughout history people have built villages, towns and then cities near a river.

This is because rivers provide many things drinking water, energy, food, a means for transport and a place to dispose waste.

In some cases a river flows into the ground or dries up completely before reaching another body of water. Usually larger streams are called rivers while smaller streams are called creeks, brooks, rivulets, rills, and many other terms, but there is no general rule that defines what can be called a river.Importance of rivers

Rivers have been used as a source of water, for food, for transport, as a source of power to drive machinery, and as a means of disposing of waste.

For thousands of years rivers have been used for navigation. River navigation provides the cheapest means of transport and is still used extensively on major rivers of the world like the Ganges and the Nile.

Rivers have been a source of food since pre-history. Apart from being a rich source of fish, rivers indirectly aid cultivation by supplying water for the crops. They are a major source of fresh water, hence, it is no surprise to find most of the major cities of the world situated on the banks of rivers. Rivers also provide an easy means of disposing of waste.

The rocks and gravel generated and moved by rivers are used in construction. The beauty of rivers and their surroundings contributes to tourist income.

Rapids are often used for recreational purposes. Fast flowing rivers and waterfalls are harnessed as sources of energy, via watermills and hydroelectric plants

Pollution of Rivers.

Rivers and the surrounding land drained by them (catchments) are very important wildlife habitats. The water itself provides the environment for fish, plants and animals, while the banks and nearby land support other creatures and a variety of water-loving plants.

There are several sources of water pollution which work together to reduce overall river water quality. Industry and agriculture discharge liquid waste products. Rain as it falls through the air, or drains from urban areas and farmland, absorbs contaminants.

Acid rain

Rain falling through polluted air absorbs some of the pollutants as it falls.

Industrial pollution

Many industrial wastes discharged into water are mixtures of chemicals which are difficult to treat. Some industrial wastes are so toxic that they are strictly controlled, making them an expensive problem to deal with. Some companies try to cut the costs of safely dealing with waste by illegally dumping chemicals at times and in places where they think they will not be caught.

Agricultural pollution

When organic farm wastes like silage or liquid manure (slurry) escape into rivers, the amount of oxygen in the water is reduced.

Nitrate pollution problems occur when too much chemical fertiliser is applied to the land. The excess runs off and can find its way into drinking water sources, or can trickle into rivers and lakes.

Other sources of water pollution

• Abandoned mines produce a large quantity of polluting chemicals. Many dangerous metals including iron, aluminium, tin, lead, mercury and cadmium come out of old mine workings. Phosphorus from sewage is another powerful pollutant. It comes from detergents and stays in rivers for a long time, taking up valuable oxygen. Few sewage works are equipped to remove phosphates.
• Careless people can also pollute rivers and harm wildlife by pouring things like used car oil and paint into drains.
• Rubbish dumps create a strong chemical cocktail called leachate. This can be deadly to fish, small water creatures and plants. In modern waste sites great care is taken to ensure that none escapes, but leachate from older rubbish dumps seeps into rivers and can pollute our drinking water.

The Murray Darling River System

Problems of the Murray-Darling River System have become a concern for people of Australia who depend on the rivers resources. They use the rivers resources so much, however, that they have exploited the rivers natural resources and they are degrading the environment.

The land has been over-cultivated and the plant life has been overgrazed. Much of the land has been cleared of its native vegetation. When the land is degraded it leads to soil erosion, more acidic soil, declining native vegetation and then weeds and other unpleasant plants will increase and cause problems. Water is also being over-extracted from the river, which is used for hydroelectric power and for irrigation. The quality of the water is becoming poor from the turbidity and nutrients being added from the erosion of the banks and from the constant extracting from the river.

Another problem with the river is the high salinity concentration. The salinity is caused by salts from the weathering of rocks, from naturally saline groundwater, and from salt deposited over thousands of years by precipitation (cyclic salt). This salinity is causing problems many of the agriculture, domestic, and industrial processes in the Murray-Darling Basin area.

The River Murray does get polluted by other things. Stormwater collects pollutants and washes them into the river. Blue-green algae contain toxic compounds that can kill stock and cause health problems for humans. Litter is dumped in wetland areas or is left lying on the riverbanks to be washed into the river with run-off. However, these pollution problems are relatively minor and can be handled simply in comparison with the more complex and expensive management needed to combat salinity.

Salinity	Water	Other environmental	Cultural	Management
Irrigation salinity andwaterlogging Soil structure and fertility decline Wind and water erosion Soil acidification Dryland salinity Pest plants and animals	Deterioration of groundwater resourcesOver-commitment of water resources Deteriorating quality: salinity turbidity pesticides bacteria and viruses nutrients	Clearance and decline of native vegetationHabitat destruction/ modification Destruction of natural heritage sites Species decline and extinction Degradation of wetlands	Deterioration of aboriginal heritage sitesDeterioration of historic heritage sites Degradation of tourist and recreation sites	Uncoordinated and inappropriate policiesFailure to apply existing regulations and policies Technical knowledge gaps Lack of community education/ information Inappropriate management practices and land use