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Tuesday, November 2, 2010

The Colorado River Essay

The Management of the Colorado River Essay

With reference to any large drainage basin you have studied."Describe the challenges represented by peoples attempts to manage the rivers processes"

The Colorado River in North America has been managed for a variety of reasons over a long period of time. The Colorado River flows through the USA and Mexico and is also 2250km long, its source is in the Rocky Mountains. The map below shows the course of the river and shows some important features to do with the river:

Management of the Colorado River basin began over 100 years ago. The reason for the Colorado River being managed is to make best possible usage of the water in the basin and to prevent flooding. The basin has the second biggest water deficiency in the USA so it is important water is not wasted. Water in the Colorado River basin is needed for domestic uses, industrial purposes and also farming. It is also important for hydroelectric power and recreation. In the Southwest USA 25 million depend on the Colorado River for water. Colorado flows through semi-arid environment and the farmland that is irrigated in this area is 800 000 acres.

In 1903 the U.S.B.R (U.S Bureau of Reclamation) was set up to control the river. The river is controlled by 11 dams in the USA. Water is also controlled for farming and water supply to urban areas through canals.
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As a consequence of the management of the Colorado River certain problems have arisen. No water has reached the Gulf of Mexico (mouth) in over 30 years, on top of this the water quality gets very poor towards the mouth of the river. The environment has also suffered due to poor water quality and also water being taken away from certain natural habitats. Due to water storage water is lost through evaporation, also in water storage dams are silted up instead of the silt being dropped on flood planes this silt is cutting the storage capacity of many of the dams. The overuse of ground water due to the deficiency of water is also causing subsistence. The overuse of ground water may show poor management of resources.

Looking at the map you can see many of the features of the Colorado River. The rocky mountains to the north-eastern area of the basin provide the source for the river it flows through 7 states and 2 countries to its mouth in the Gulf of Mexico, other mountains are within the river basin. The land that it flows through is semi-arid and desert in some areas, much of the land is scrubland. The climate in this region is extremely hot all year round and there is low rainfall virtually non in the summer. In winter it will often snows to depths of 2 500mm in the mountains, in spring this snow melt creates a lot of water. Without management the river may flood from time to time depositing silt on any flood plane this flood will also recharge groundwater supplies of water, this no longer occurs due to management. The rock in the river basin is predominantly red sandstone, which is very soft and easily eroded. The diagram below shows a typical climate graph for a location in the Colorado River basin region:

Agriculture one of the main users of water in the region mainly grows citrus fruits there is also a lot of cotton growth. These are not very lucrative crops and farming of these crops depends largely on government subsidy. On top of this the crops are relatively thirsty ones demanding a lot of water to grow, so they are a little un-suitable for a semi-arid environment where there is a water deficiency. Therefore the crops need to be irrigated using water from the Colorado. This seems to be a little strange that crops are grown in an un-suitable environment relying heavily on a scarce resource and the crops are not very lucrative in the first place. It is also difficult to see why they are heavily subsidised when that type of farming is clearly not compatible with the circumstances. However farmers hold a lot of power in U.S politics with groups such as the California Farming Lobby preventing the removal of subsidy. However the government did find one way of cutting water usage, 10% of farmland in the region was bought by the government cutting the level of subsidy and cutting water usage. For water the crops are irrigated, in the past a technique called flood irrigation, in this the crops are flooded by water around the base, the water comes from the Colorado directly or through a series of canals. Through this technique a lot of the water is lost into the ground. This technique of giving plants water is obviously not sustainable because of the amount of water lost however at present water is cheap enough so it does not matter. Due to this waste 2 things have been done, firstly drainage systems installed so that water can be put back into the Colorado if it was not taken back into the plant. Another technique that has not yet been used so widely is a different form of irrigation. Drip irrigation involves a series of pipes laid underground and releases water directly onto plant roots giving it the exact amount it needs is provided, this technique avoids water loss. A lot of water is also used to flood fields to get rid of salts to lower salinity levels.

However it is very expensive to install this form of irrigation and farmers will not pay cost so the government has to pay 75% of the cost. However in the long term this type of project could save money for farmers as it uses far less water than the alternative form of irrigation. Another downside apart from the initial start up cost is the cost of maintenance as the pipes are underground. There is also downsides to using drains to put water back into the river. Salts from the soil are dissolved into the water and when the water re-enters the Colorado the salt is with it. Farming in the Welton Mohawk Valley in Arizona uses this irrigation technique. As well as salt entering the river through excess water salt enters the river when farmers flood fields to to lower salt levels. A high salinity level prevents crops from growing as it prevents growth. Salt is removed from a surface crust or soil by flooding the field the water dissolves the salt and re-enters the Colorado.

The accumulation of salt in the Colorado is so bad that Mexico demanded a change because by the time water reached Mexico it was of such a low quality that the farmers could not use it. The initial agreement between Mexico and the USA guaranteed 1.5million acre feet per year but didn't include any detail over water quality. The water was 10 000ppm (marts per million) salt, similar to brine as it entered Santa Clara wetlands in Mexico. As a result a desalination plant was built in Yuma in the far south of the USA. A desalination plant removes salt from water making it useable again. It was started in 1974 and took 18 years to build at a cost of $500 million and even after completion it was only operational at a third of its capacity. However it worked water entering Yuma was desalinated and left at only 215ppm and mixed back with water with a higher concentration lowering the overall salinity of the water.

Due to this problem of salinity water from the Colorado can effect the environment significantly. The water with high selenium content flows onto wetlands killing plants and animals living there. Selenium is one of the minerals collected from the ground, it is safe in small amounts however it accumulates to dangerous levels. In Central Valley California 95% of wetlands have been destroyed through poor quality water or drying up from not enough water reaching them. In Kesterson
a wildlife refuge the San Luis Drain allowed water to flow to Kesterson that had such a high level of selenium it could be considered toxic.

The effect of this high level of selenium was devastating. Birds such as Coitus were born with severe deformities such as small eyes or total lack of eyes, legs, feet and wings were sometimes missing. No Avocet chicks survived past 1 year. As a result of this the San Luis Drain was blocked and the Kesterson reserve had to be filled in because it was considered as a risk to human life and their was no way that wildlife could return in the state it was in. The drain from the water table ment there was a net build up of 2 million tonnes per year of minerals and salts.

The other problem of wetlands drying up was due to too much water being used up by farmers or people in cities. In North California their used to be miles of free flowing streams now due to the lack of water supposedly natural environments have to be controlled artificially to actually survive. A complex network of pipes and science keeps the wetlands in existence.

Settlement the other major use of the Colorado River's water has extended dramatically over the past years since. This has put strain on the resources as very sudden growth has occurred in Las Vegas, Los Angeles, Phoenix and Arizona. In Las Vegas at current rates of growth 60 000 people are entering every year needing 15 000 new houses every year to deal with this. In Phoenix and Arizona 500 000 people have moved in the last 10 years. In total 25 million people depend on the Colorado River water, in 1930 only 3.4 million people lived in the region. Also in recent years peoples demand for water has increased due to new technologies and increased wealth. Things such as washing machines, dishwashers that have become household products in recent years use a lot of water, also things such as swimming pools that are becoming common place in houses in Beverly Hills use a lot of water obviously also associated with the affluent are there large green lawns which need sprinkler systems to support them. In Las Vegas people use more water than anywhere else in the world, 300 gallons per person per day. This doesn't sound right considering Las Vegas is in the middle of a desert. Other things use a lot of water for example many rich people enjoy playing golf and throughout the region there are country clubs with lush green golf courses a lot of water would be needed to achieve this in such an arid area.

This type of growth in water use and populations is obviously not sustainable in a semi-desert environment. A new Denver airport has been built in the desert which will encourage even more people to the area through accessibility for bushiness and industry. At present complex networks of pipes and canals are needed to get water to cities around the USA's Southeast. Ground water supplies which previously supplied cities such as Phoenix are drying up causing the water table to lower, this means water is out of reach and it can also cause subsistence if too much water is extracted. What is happening is the ground level is lowering this will result in cracks across the surface which can cause damage to buildings. For Tucson's water supply $3.5 billion was spent on a system which pipes water over mountains to get there. Other projects are also having a lot of money spent on them to provide water to cities, the Central Arizona Project which pumps water 500km across the Arizona desert to Phoenix is a good example. This project has been heavily criticised as it was highly costly as dams and pumping stations needed to be built flooding fertile farmland that Indians lived on. The project involves pumping water 700 meters up a hill using costly amounts of electricity and once the water reaches Phoenix it is of poorer quality as water is evaporated on route leaving a more salty water. At the end of all of this 90% of the water is used for farming yet only 3% of Arizona's income comes from farming. At the end of the day people may not think all of the money spent and use of the precious resource is worth it as large amounts of it are not essential.

The water rights issue or the way in which water should be divided up is made an even more contemptuous issue after huge amounts of money have been spent on providing links between cities and the Colorado River. This is because if it is decided certain areas will receive less water it would make some of the schemes partially redundant. The Central Arizona Project will probably have to take some water away from the Southern USA allocation. In the future their will have to be a point when growth has to stop because there is simply not enough water to sustain current growth levels, water will also have to be used more sensibly.

After looking at the present management of the Colorado River it can be seen it is fulfilling many of its needs in providing water for agriculture and for people. However it is clear that the Colorado is not being managed very well.

Land surrounding the Colorado should not be farmed in the way it is because the climate is clearly un-suitable thus making it more expensive to produce things than other parts of the world. Farming should carry on as it is an important part of the economy and a food resource however the level of farming should be reduced. In some areas 3 crops are harvested a year because the land has such a high real estate value farmers need to get as much from their land as possible which in uses more resources. Farmland should be cut down on however not sold to real estate as this would only increase demand for water through housing. This could achieved by government buying more land from farmers also if subsidies were removed from farmers it could effectively drive them out of business however the political system in America makes this an un-likely prospect due to the power held by farmers. In the short run alternative irrigation should be looked at so to avoid water wastage and salt levels increasing further. Other crops should be looked at that are less thirsty, for example Bladder pod which can be used for oils.

Cutting down on farming would also reduce the problem caused by salt by reducing the amount of salt that is accumulated in the water. To solve problems already caused a microbe has been discovered that will remove selenium, this could be used at Kesterson. The San Louis drain is a good example of how the Colorado River has been managed poorly, the failure to plan finance and finishing point for it resulted in serious environmental damage.

To control population growth and there use of water there is not much more that can be done except higher water prices so people are more careful with the way in which they use it and do not waste it. Also household appliances should use lees water an example of this is a low flow shower head, so less water is used when people are in the shower Stricter planning regulations can also be implemented so that it is more difficult to develop land discouraging new houses and more people moving to the area.

Mexico and its water rights should be looked at as it is clearly not fair the amount of water supplied to Mexico and the quality of it. The desalination plant is another example of where management has not been very good, the length of time it took to build the plant in Yuma and the Fact it was not being used to full capacity shows management's lack of thought for the Mexicans. Mexico should have more of a say in what occurs up river as the consequences are felt down river. A forum could be set up to decide water rights, flood control techniques and water quality.

To conclude the benefits of management do outweigh the disadvantages as management has promoted growth in the region in population, industry and farming on top of this flood control. However each of the 3 areas shown above should be managed better. A sensible level of each of these should be obtained so water can be provided for each whilst keeping in mind the environment.

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