Ten African countries share the world's longest river, the Nile. Its basin has long been a place of dispute, even war and without agreement, increasing demands for water could lead to real conflict.

In an unprecedented move, the countries of the Nile basin met this summer to solve animosity and share resources through international co-operation.

Earth report travelled along the length of the Nile, from Rwanda to Egypt, to see what issues communities along this great river face and how this new initiative could unite them at last.

Source of the Nile

The British used to think that the source of the Nile was in Jinja, Uganda. But it's not that simple. There are headwaters in Burundi, Rwanda, Tanzania and Kenya.

The Nile provides life and sustenance for the 300 million people who live either side of it - a number that is predicted to double in the next 25 years. Of the ten countries that share the Nile, four are part of the ten poorest in the world.

As the population rises so does pollution and water usage. Now less and less water is finding its way into the basin - threatening the livelihoods of the communities that share the river and the stability of the region.

'Hope and the Nile' begins its journey at its headwaters in Rwanda.

Protecting the source, Rwanda

The highlands of Rwanda - home of the mountain gorillas - are crucial to the existence of the Nile. Rain captured in these forests end up, nearly 7000 kilometres north, in the Mediterranean.

Rwanda's troubled past has left development at a standstill. Only 2% of the population has access to electricity while the rest use massive amounts of wood to provide all their energy needs, severely damaging the environment. Finding an alternative energy source is an important factor in protecting the environment.

Water falls: hydro power

At Rusamo Falls in Rwanda, hydropower could generate 60 megawatts of electricity. But big dams cause big problems: displacement of peoples, flooded ecosystems, the destruction of wildlife habitats and greenhouse gas emissions from flooded vegetation. At the moment, though, there's no doubting the need for development.

And there's another problem. Decline in water quality has led to an explosion of water hyacinths along the Kagera River, which could clog generator turbines downstream.

Pest control, Uganda

The invasive hyacinths came to Uganda at least 60 years ago. Their numbers grew out of control and they spread throughout the Nile. Today they cover Lake Victoria - the freshwater inland sea that feeds its shoreline peoples with fish.

Introducing a small beetle that feeds on them might control hyacinths and research stations are now testing to see if the idea will really work and if the hyacinth can be controlled then the densely populated shores of the Lake can return to normality, and development.

Pollution control, Lake Victoria

New fish species and a growing population around its shores are also changing the ecology of Lake Victoria. Unless something is done, the next problem will be sewage destroying the ecology of the lake and reducing fishing productivity - which could have devastating effects on export markets.

Saving the soil, Ethiopia

Over to the east, the Blue Nile rises in Ethiopia. Once this was all woodlands and a desirable place to live. Trees conserved the water and the land but over-population and droughts laid the land bare and open to erosion. And the pressure on land is not going to ease. Ethiopia's population is set to double in the next 20 years to 130 million. Some things, though, can be done.

Planting trees and vetiver grasses can stop erosion-gullies opening up and help stabilise soil - preserving fertile topsoil and reducing the amount of silt runoff into the Nile, which causes poor water quality downstream in neighbouring Sudan.

Like Rwanda, Ethiopia could aid development with hydroelectric power (HEP). Its mountains provide huge potential for sustainable HEP. But Ethiopia supplies 85% of the upper Nile waters and damming its headwaters could cause conflict. As yet, Ethiopia, has not agreed any water rights with any other country.

Silt and sand, Sudan

Downstream in Sudan, silt-laden tributaries cause floods, change river flows, damage irrigation and destroy trees. As a result there is little natural defence against sand dunes, which smother the narrow strip of arable land along the river's edge that sustains thousands of communities. The loss of pastures, houses and livelihoods forces people to pack up and leave.

The only answer is to bring back trees and try to mend the eroded riverbanks. It's happening in a few places but there's desperate need for major replanting.

Half of the water of the White Nile is consumed in the largest wetland of the world. The Sudd - unique, inaccessible and little understood - is under threat from potentially disastrous development ideas. Plans to drain the swamp and explore for oil could leave the Sudd as devastated as the delta region in Nigeria.

Greening the desert, Egypt

Khartoum is where the White Nile and the Blue Nile become one. To the north lies Egypt.

Here, water is priceless. 70 million Egyptians are totally dependent on the river because most of their country is desert. They've always made sure they have the waters of the Nile to rely on. But after 7 millennia, it's only recently that Egyptian regional pre-eminence has been tested.

Egypt is realising that the Nile is not an infinite provider. It's coming to terms with limits of growth. Ambitious projects, like the greening of the desert, have only been partially successful.

Traditional methods of irrigation have been replaced by modern technology, but wastage is high. A project to share water more efficiently between farmers is being tried that involves mechanizing larger wheels and channelling to a greater number of fields.

Nile Basin Initiative

With natural resources already stretched to the limit, the potential for hostility over water is huge. The plan is to head off that threat, protect the Nile and give its people new hope.

The impacts of runaway ecological problems, creeping desert, limits to growth and sheer, dire poverty, are seemingly intractable problems. In a quagmire of war and tension, the chances of solution have seemed thin.

But after years of negotiation, it now seems the beginnings of a solution might be possible. In Geneva this summer (2001), all the involved countries came together to announce the formation of the Nile Basin Initiative.

Efficiently using limited water supplies for energy and food production, and rebuilding a severely damaged environment are big issues for all the countries of the Nile basin. Trying to give people a better life is an even bigger issue.

Like anywhere else the problem is the balance between development and natural resources. With an initial plan for 3 billion dollars of investment from international donors, and a lot of soul searching, there's now a commitment to try to find sustainable solutions for global security, poverty alleviation and conservation together.

Common resource, shared responsibility

The Nile is the thread that holds ten of Africa's countries together. But historically these countries have competed with each other over the resources of the Nile. The peaceful future of this region lies in accepting this commonality and creating a reality where the longest river in the world is shared equitably between all.