Lesson 16. Transformation of arid lands

I. Выучите новую лексику урока:

fix v укреплять, закреплять phenomenon n (р1 -mena) явление;

invade v 1. нарушать; 2. вторгаться; необыкновенное явление

3. посягать на чьи-л. права dominate v доминировать,

bog n болото, трясина преобладать

subsoil n подпочва alarm n тревога

relevant a 1. применимый, halt v останавливать

уместный; относящийся к делу; replenish v пополнять, восполнять

2. значительный

II. Прочтите и переведите текст: Text a. Deserts of the XX Century

Water fixes the use potentials so completely that land without it is almost useless for agriculture. The deserts invade in many forms — wind erosion, droughts and moving sands. Quite often the advance is linked to the concentration of salts in the soil and subsoil waters. Land conservation there­fore means to halt the advance of deserts. Relevant measures which involve applying scientific and technological achieve­ments to make use of deserts are well-known in Asia. The land conservation involves also taking into account the desert's natural capability.

Land use planners believe that the prime condition for the development of arid zones is to investigate the phenom­ena occurring in them. To do this the scientists have to watch systematically the natural indicators enabling us to forecast the advance of the desert in good time.

The first signal of trouble is an increased concentration of salts in the soil and subsoil waters. Then come changes in the vegetation cover. The vegetation thins out, drought-resistant and salt-loving types of plants begin to dominate and the biological productivity of the land falls. Wild animals leave. The final and most alarming signal is declining health among the people living in the area.

A wealth of information is now beginning to come in from outer space on the state of pasture lands, and of artificial and natural water bodies. The space satellites information makes possible the forecasting and avoidance of undesirable phenomena caused by man's activities.

Specialists have also developed practical protec­tive measures. Among them are mechanical means, planting forest belts, grasses, and bushes, and using oil waste and pol­ymer film to halt the movement of the sands.

III. Прочтите и переведите текст: Text b. Land Reclamation and Water Resources in Arid Areas

The shortage of fresh water has the greatest influence on the entire natural complex. But it operates in the arid areas more intensely than anywhere else. That is why dealing with any economic problem in a desert begins with an assessment of water resources for the sake of land reclamation.

Artesian wells are quite spread in Kazakhstan and the Central Asian Republics. The water for the city of Shevchenko is obtained cheaply from an atomic desalting plant. High-capacity irrigation systems operate in Turkmenia and Uz­bekistan, getting water from the Kara Kum and other canals.

But Central Asia's biggest rivers, the Amu Darya and the Syr Darya, do not carry enough water any more. So a new problem arose — how to save the Aral Sea which will not be able to replenish itself with water from the two rivers. The further economic development of the lands of the Republics of Central Asia and Kazakhstan will demand additional amounts of water.

The land use planners as well as many other specialists have developed a number of projects for ways of bringing water to the deserts which will help to alter the climate of vast areas.

However, obtaining the water is not enough. It must be used rationally. Today, between 15 and 30 per cent of the water in irrigation canals is lost in the Ferghana Valley. These waters were the cause of appearance of salty bog lands. Cement or clay solutions are being used to cover the walls of the canals, but these are very expensive methods. Feeding water through pipelines is a new way of combating water losses and the salination of surrounding territories. Sending the water through flexible plastic pipes is especially effective.

Supplying water to the deserts in Central Asia and Kaz­akhstan and developing new methods of transporting it, land irrigation make it possible to protect the soil in arid zones from salination and end the threat of wind erosion.