Rivers are systems that require management in terms of flooding, supply, and pollution control. Discuss various strategies using different case studies.
Every river experiences a flood in some point in time. This may be due to an effect of heavy rain or humans tampering with the surroundings of the river. However due to the large build up of settlements around rivers flood control is needed as many lives and settlements can be lost during such an event.
A good example of flood control can be seen along the Yangtze River. The Yangtze River is the third longest river in the world and is situated on the Tibetan Plateau in china. It reaches a length of 6300km and has a drainage basin of more than 1,683,500 square meters.
Since 1931 seven major floods have been recorded. In 1931 there were estimated 28 – 40 million people affected 140,000 of which were deaths. In 1954 there were 33,000 deaths. In 1981 and 1991 floods arose which submerged large areas of land. In 1995 there were 1300 deaths and an astonishing 100 million people affected.
In 1998 the largest flood hit the area surroundings of the Yangtze River, recorded for over half a century. The level of which the river rose to was maintained for over two months. There was an estimated 3000 deaths. 5.6 million homes were washed away, 30million made homeless and extremely large areas of cropland destroyed. 100,000 soldiers and police were needed to strengthen the jingjiang and other levees. They had to work for in teams 24 hours 7 days a week for 2 months. On July the 21st, an uncanny 280mm of rain fell on Wuhan in 24 hours.
The next day the city experienced the first of the several flood peeks, which occurred during a two-month period. By the 2nd of August the Dongting lake reached the all time high where there was nowhere for extra water to go as areas around it had already been flooded for 30 or more days. By this stage the government had given the information that they were sacrificing the smaller villages and towns in order to lessen or stop the blow for the larger settlements.
In 1999 in the middle of July their were 240 deaths, 1.84 million evacuated and 660,000 ha of cropland flooded from the cause of a flood.
Due to the number of casualties caused by floods it was vitally important that some sort of system of flood control needed to be implemented within the Yangtze river.
Due to the large variance of the river height of the Yangtze river resulting in flooding, this area needed to be addressed. This was done by implementing a 10 – 20 year frequency by repairing and/or strengthening current levees.
Water was diverted into large lakes near the Yangtze e.g. into the Dongting lake.
Flood diversion areas were also made. However the areas in which there “diversion areas” divert water to are relatively highly populated areas (population exceeding 400,000).
The main flood control system that was implemented is the three gorges dam as it lets the main flow of water out gradually decreasing the chance of flooding. This has two uses as it decreases chance of flooding and provides a relatively reliable source of electricity for some parts of china (as theirs such an abundance of water energy). Figure one shows the main features of flood control along the Yangtze river.
The river Rhine is one of the longest rivers in Europe. It is 1,300 Meters long spanning from Switzerland to the Netherlands. 35,000 vessels regularly travel along it as it is also used for importing and exporting goods. The river is also used for fishing, tourism and recreation purposes. The actual water is used for domestic, industrial and agricultural purposes.
Figure 2 is a picture of the river Rhine
Unfortunately the river Rhine has a very big pollution issue. The first settlers who moved next to the river Rhine used the river as a source of dumping their rubbish. Initially this was fine as the river was able to cope with cleaning it self until the industrial revolution. The problem, which came with the industrial revolution, was that not only the sheer amount of pollution increased but also the type, which included industrial effluents, mix with domestic waste, sewage, phosphates and heavy metals like lead and mercury. The amount of pollution that entered the river had to be controlled as abnormality was even occurring due to people drinking the bad water.
International co-operation of cleaning up the River Rhine dates back to 1887. In 1887 a treaty was made that prohibited people to dumb wastes, which were dangerous to fish. However By 1946, the situation had deteriorated even more. Due to this the International Commission for the Protection of the Rhine Against Pollution (ICPR) was formed. In 1986 there was a serious incident, which led to the Rhine Action programme (RAP) to be developed. The aim of this programme is that by the year 2000 all of the species such as the salmon which once thrived within the river to be put back.
The specific aims of the Rhine Action Programme to protect the river Rhine against Pollution are:
* To accelerate the reduction of permanent pollution from all sources
* To reduce the risk of accidents and spillages
* To improve hydrological and other conditions of the river
At the National Level
* National laws are made stating how much waste material can be discharged
* Industrial plants are obliged to have a permit for their emissions
* Pollution taxes are imposed on individuals and industrial plants
* Purification and measuring stations are built
At the International Level
a) There is more co-operation between countries that share the Rhine
b) There is an alarm system for every time the concentration of a certain material exceeds its permitted value.
c) Plans are made for the conservation and restoration of natural landscapes.