The fertile land on the floodplain of the river can be used for agriculture and also recreation such as football pitches, which don’t need protection if the river may flood. Agriculture also takes place on valley sides, such as grazing for animals especially sheep in Scotland.
Many major cities have rivers running through them, The Thames runs through London, The Seine through Paris, The Nile through Cairo, and the East River and the Hudson River through New York are just a few examples. These huge cities were once just small farming settlements, being such an ideal situation for a settlement they have grown to the size they are today. The wide flat valley floor of the river in it’s lower course provides good land for building on, the fertile land which was once what first provoked settlement can be used for farming. The cities depend greatly on the river for a source of water and for transport and trade.
Along the Thames, in London, the Docklands was once an example of a river being used for trade. The Docklands became a large industrial settlement relying on the Thames to transport goods in and out of the docks. The surrounding area next to the river became built up with large factories and small terraced houses for the factory workers.
The river itself is very important to industry. Starting an industry next to a river gives a great advantage as the river can provide transport for both the finished product put also and material you may require producing the product, along the length of the river and as an import or export from overseas. Also hydroelectric power stations can use the river to provide an energy source for the surrounding industry or settlements.
On the valley sides of the upper course of the river both forestation and deforestation may occur. Logging companies will choose to set up business as land is cheap so they can buy areas of forest and cut them down and then plant new trees to grow in their place.
If the river is used as a water supply and a reservoir is created, usually in the upper course, the reservoir can provide recreational activity such as water sports or fishing.
The river and its environment provide us with many benefits from its use. The river, however, is caused much harm us, creating much dispute from environmentalist. The use of river environments causes much conflict, not only between the river, and us, but also amongst ourselves.
Over the last one hundred years, river channels have been altered to prevent flooding and to aid transport and reduce erosion. They have been altered by the method of channelisation. This alters the cross-sectional gradient and flow characteristics.
The River Trent that runs from its source at Biddolph Moor, north of Stoke-on-Trent, to the Humber estuary has been channelised to prevent flooding. The potential hazards from flooding have been made worse in Nottingham by the further growth of the urban area onto the floodplain. This has caused more surface runoff and a faster rise in river levels. However, changes made to the river channel and the floodplain since 1947 have successfully reduced the impacts of flooding.
Whilst channelistation of river channels may extend over great lengths, the building of a dam is at a specific location. The impact of the dam is not, however, kept within the small proximity of the dam, but may cause conflict to areas further downstream and the surrounding habitat.
One of the largest and most controversial dams is the Three Gorges Dam on the Yangtze River in central China. The scale of the resettlement programme and the possible environmental effects of the dam have caused great political and public debate. Pressure from environmental groups and doubts about the effectiveness of the scheme have caused some investors and foreign consultants to pull out. A major concern is the large amount of sediment carried by the Yangtze, which will be trapped behind the dam. In order to reduce sedimentation rates, it is likely that the sediment rich water, which arrives mainly during the four-month flood season, will be released from the dam and only stored water flowing in the reservoir between floods will be stored. The irony is that this will reduce its effectiveness as a flood control measure.
As urban areas increase in size and number, the capacity to affect hydrological processes increases too. In comparison with rural areas, inputs of water into the urban hydrological system tend to be greater. This is due both to urban areas tending to receive slightly more rainfall due to localised climates conditions, and to transfers of water piped into urban areas from elsewhere within the drainage basin, or even outside it.
The surface characteristics of an urban area will also alter the hydrological processes because they tend to be smooth and impermeable, with less surface storage capacity. Storm drains also carry runoff water from roads and pavements, so the speed of flow of precipitation travelling to the river channels is greater causing much water to arrive at the same time, increasing the risk of flooding. This results in the hydrograph of a river affected by urbanisation to have a short lag time, showing the lack of delay in the precipitation event reaching the channel.
Increase in discharge as a result of urbanisation can cause unintentional changes in river channels. An example of this is Monks Brook in southern Hampshire. Before urbanisation started in the 1930’s, the area was used mainly for agriculture. Housing developments in the 1950’s, 60’s and 70’s has increase surface run-off and peak discharges. This has caused the width of the river channel downstream of the urban settlement to increase form 4.25m in 1951, when urbanisation began to increase to 6.30m in 1991.
People have also affected the water quality in river environments. Small pollution events are usually responsible for much of the environmental pollution. In the UK some polluting substances are quite legally pumped into streams and rivers if a licence has been obtained from the Environmental Agency.
Sewage treatment works disposes of the UK sewage wastes within rivers. This causes a nutrient source for bacterial populations living in a river. As the bacteria decompose organic waste they use up the oxygen in the water. Nitrate pollution from agricultural land has much the same effect; the nitrates cause weeds to grow in the river which when decomposed use up the oxygen within the river, killing all living animals such as fish and frogs.
Recently pharmaceutical drugs given to people and domestic animals are being found in surface water and groundwater. A typical sample of water contains within 30 and 60 drugs. The high quantities of antibiotics in rivers allow bacteria to build up a resistance. Super bugs, such as E-coli, are the inevitable consequence.
The River Trent is well known for it’s poor water quality. This is due to the large centres of population such as Stoke-on-Trent, Nottingham and Derby, as well as the industrial development that gradually grew within the river’s drainage basin. Poor effluent and sewage treatment led to deterioration in the quality of the river water. Sine the 1960’s though, improvements in effluent treatment and legislation to prevent pollution has produced a marked improvements.
The improvements have lead to another pressure and increasing demand for water has made the Trent a potentially new source for abstraction. This has again made a potential conflict between abstraction and other uses of the river, mainly because a minimum flow is needed to dilute the sewage and industrial effluent in the river to protect the environment, to preserve the coarse fisheries, maintain sufficient water for navigation and maintain flows for recreational users.
Conflicts may also occur when water is removed from groundwater sources, this often occurs if a quarry is built to drain it. It is very difficult to predict the amounts of water, which can be removed from ground water sources without causing adverse affects. The results of over-abstraction are an increasing cause for concern. This can cause loss of wetland habitats as the water table drops. Shallower boreholes may run dry, leading to problems between different water users. Soil and rock, especially clay and silt, may settle and cause subsidence at the surface. This could affect buildings, roads, railways, canals as well as pipes and wires underground. There is increased likely hood that sea water will contaminate wells in coastal areas (sea water intrusion). The California seawater has penetrated at least 5km into ground water in some areas. Reduced river flows, some rivers may only run seasonally and many rivers rely on groundwater stores for their flow much of the year round.
A very different problem has started to affect some British cites. Groundwater levels have started to rise as a result of tighter restrictions being placed on groundwater abstraction and because of the closure of many heavy industries that abstracted water. There is now fear of more frequent flooding and that groundwater could become more polluted as it rises closer to the surface and comes into contact with contaminated soil.
Flooding is one of the devastating effects our use of river environments contributes to. In July 1997 intense rainfall lead to devastating floods in Western Poland and the Czech Republic. Towns and cities where inundated, bridges and roads where washed away, agricultural land was rendered useless and 56 people lost their lives. More than 10% of Poland’s land area was affected by the flooding. The impacts of the high rainfall where undoubtedly affected by the land use within the Odra drainage basin. The treat of flooding in Wrocklaw was so great the authorities considered extreme measures. Instead of reinforcing the embankments upstream of the city they considered using explosives to demolish them. This would have caused the flooding of the Widawa basin, which contained villages and suburban areas. This would have dispersed some of the water away from the river channel thus reducing the water flow. The inhabitants living close by to the threatened embankments objected strongly, even chasing the engineers in charge away. The embankments did remain and the flooding in Wrocklaw was severe.
The human activities contributing to the flooding were, that no water was released from the storage reservoirs at Nysa and Otmuchow before the flood arrived. This would have increased their capacity to store floodwater. Leaking at the base of the Nysa dam required emergency release of water, flooding settlements downstream. The Odra has been channelised in many places to improve transport. The length was reduced by 16% this has speed up the flow of water. Emergency reservoirs have not been maintained properly. Many have silted up. Deforestation has occurred, of which vast numbers of trees were re-planted but due to air pollution, especially acid rain, means they are less healthy. As a result, surface run-off and stream discharges have increased. Tracks and settlements built in the hills have led to an increase in surface run-off. Reservoirs built to defend settlements against flooding have given people a false sense of security and so settlements have developed on the floodplain.
Tourism within river environments creates much conflict, between the local villagers and the tourists but also between the environment and the tourists. As a result of hikers, horse riding and cycling around the landscape causes path erosion, and soil erosion. This could lead to increased amounts of sediment reaching the river channel. As would any increase in people in the environment, noise pollution would increase; this may scare away rare wildlife species from their habitat. Also, an increase in the number of people visiting an area is bound to get companies setting up business, causing better or more roads being built to an area, destroying the landscape but also creating air pollution as well as noise pollution. The building of new roads or buildings in an area is bound to upset the villagers already living there but also may cause the arousal from environmentalists or conservationists would believe that the landscape is precious and should not be interfered with. Deforestation also creates national upset from conservationists.
Rivers can cause global conflicts and wars if they run through more than one country such as the Amazon River. If the country which the river travels through first disrupt it by building a dam and trapping the sediment, it will cause problems for the country the river runs through next. This could result in wars if the first country take huge amounts of water from the river for irrigation of keep the flood gates shut on their dam. If the second country was in a time of drought then they might get angry if there was not enough water left by the time the river reached them, or if their crops would no longer grow as well due to a lack in sediment.