The water carries a heavy load of eroded material — the process of transportation. Mud, silt and sand are carried along by the current, while gravel, pebbles and rocks are pushed and rolled along the river bed.

Whenever the river slows down it drops its load — the process of deposition. Deposited material is naturally and precisely graded, the heavier pebbles and gravel settling out first, followed by the finer sand and silts.

Through these three processes rivers are constantly shaping the landscape.

Reservoirs

Rivers are the main source of water in many areas and reservoirs are an excellent example of how this vital natural resource is utilised and managed. Dwr Cymru Welsh Water use the Usk Reservoir not only to supply a large area of South Wales with water, but also to regulate the flow of the river.

River Basins

The area of land drained by a river and its tributaries is called a river or drainage basin. One river basin is separated from another by a natural ridge called a watershed. Rainwater runs down either side of this ridge just like on the ridge of a roof, flowing into one river basin or another. The Amazon’s river basin is the size of Europe!

Land Use

River valleys provide a huge variety of different land use opportunities all along their course. Open moorland is ideal for forestry, upland valleys are excellent sites for reservoirs, communication links follow the river’s path cut through the hills, and tourism is attracted to the natural beauty of the valley scenery. Further downstream, the valley floor is used increasingly as building land for housing, settlement facilities, water treatment and sewage works. Finally, the wide, flat area around the river mouth and estuary provides cheap land for commerce and industry.

All of these compete, and at times conflict, with the traditional use of agriculture, dominant on the rivers floodplain due to the rich, deep soils created by thousands of years of flooding.

Settlement

As the old border between England and Wales, the River Usk was historically and strategically important. Over the centuries it attracted a large number of settlements along its banks. These villages and towns developed at key bridging points where the river provided water, food, transport and communication links. Bridging points are an important geographical feature and the Usk is crossed by an amazing number of different types of bridge, from ancient to modern.

Brecon is a classic confluence town, having grown up where three rivers meet — the Tarrell, the Usk and the Honddu.

Communication Links

River valleys always provide the route for key communication links. All the main roads of the area, the railway and the canal follow the path cut through the hills by the river.

(Note: the printed version of the Riverflight Teachers' Guide is available as part of the Riverflight Map Pack from the 4Learning online shop.)