What are the disadvantage of rivers?

Answer 1

The positive impacts are demonstrated in the following possible benefits and uses of the multipurpose river valley projects:

• provides work
• eliminates flooding
• provides power
• provides water for human consumption
• helps to conserve water
• provides water for agriculture
• provides water for industrial uses
• provides for a fishery where one may not have existed before
• changes the ecology of the region
• opens new areas to agriculture

Negative impacts may include:

• they lead to the displacement of human, plants, animals, chiefly from small tribal communities;
• disrupt downstream fisheries;
• increase the risk of earthquakes;
• submerge forest land;
• increase the spread of insect-borne diseases; and
• threaten the fragile regional ecosystem through reducing, the flow of water from the rivers into the seas.
• These projects initially devastate human lives and biodiversity by inundating thousands of acres of forests and agricultural land.
• They degrade the fertile agricultural soils due to continuous irrigation (rather the seasonal irrigation which is dependent on the monsoon), and salinization, making the soil toxic to many plant species.

Refer to questions below for more information

Answer 2

Projects labled as multipurpose generally refer to a water retention system which is used to a) generate electricity, b) act to prevent water shed flooding, c) provide irrigation, d) naviagation e) habitat improvement and f) improve fishery populations. However, in most cases the "e" and "f" are fictions that people are told but do not occur.

These projects also generally displace hundreds of not millions of people from very fertile land thus reducing the productivity of these people. They take away their livelihood and their homes of many generations.

So do the benefits out weigh the cost. Most countries building these massive projects seem to think so. They do produce lots of benefits, the most important of which is energy. However,, if you consider the Aswan High Dam in Egypt which prevents the Nile from flooding yearly, the power generated by this massive dam is used to make fertilizer. Up to 30% of the electricity generated is used for the industrial production of fertilizer which is needed to keep the fields fertile which in the past was taken care of by the flooding of the river. The lake behind the dam is also silting up at a rate 2x what was thought to be so the useful life of the reserviour will be less then 100 years.

There are a lot of considerations which must be reviewed before such a project is undertaken and if it is not done properly, the value of the project is greatly reduced. Unfortunately, there are time when this negative information is intentionally suppressed to get the project passed when it should have been stopped before it was built. Today many old dams are being demolished because they failed to achieve the expected goals.

Answer 3

when excess of water enters the reservoir or dams due to waterfall or any other reason, the dams then are bound to give out their water in the river in case not to break the walls of the dam. This causes an uprise or upliftment of the river water which then enters the villages and henceforth causes floods.

Answer 4

sure rivers provide fish and clean water but, they can easily be overflowed with too much rain and ,with excessive activity and little rain, can become dry for many months. also rivers wear away with fast-flowing current into the sides of a river. also riverswith the wearing away affect can create an oxbow lake. this link can show you more about lakes. geobytesgcse.blogspot.com/2006_11_01_archive.html

Answer 5

In recent years, multipurpose projects and large dams have come under great scrutiny and opposition for a variety of reasons. Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers aquatic life. Dams also fragment rivers making it difficult

Answer 6

The greatest disadvantage of multipurpose projects is the harm they cause to the environment. Obstructing the natural flow of rivers for the purpose of building dams creates inhospitable conditions for the marine life, which results in the death of many aquatic animals and plants. Also, big reservoirs submerge the adjoining fertile flood plains causing great loss of agricultural land. Many river valley projects such as the Sardar Sarovar have submerged the nearby forests, thus contributing to the depletion of India's forest resources. Another major disadvantage of multipurpose projects is the large scale displacement of people. The local communities have to leave their villages, their livelihood and their ties to make way for these projects. Their rehabilitation is a major issue that is being raised by several social activists such as Medha Patkar. The people who give up their land for the good of the nation are the one's suffering the most as after their displacement. In most cases, they are not provided proper food and shelter.

Answer 7

While there are many advantages to these projects, they can also harm the environment. Many plants and animals from that area will no longer have a home.