Lecture 4 Surface and Underground Waters

There are more than 17,000 rivers in the Altai Territory. 776 rivers are more than 10 km long, 32 rivers are more than 100 km, and 5 rivers are more than 500 km in length. The Altai territory lies at the top of the Ob basin. The Ob is formed from the confluence of the two rivers, the Biya and the Katun, and flows through the plain as a full river. Most of its tributaries are small. The Ob gathers most of its water in the Altai Mountains, where many rivers flow from the glaciers. Their currents are swift and the riverbeds abound with rapids. Tectonic ledges from solid rock create a picturesque scene with waterfalls. The rivers in some parts are almost rectilinear or their outlines repeat the direction of the tectonic heaves. In the middle of the rivers’ length, the character of plains changes as they widen and become gently sloping. On the plateaus and in the mountain hollows the rivers re­semble plain streams. All of the rivers flowing through the lower part of the mountains and foothills have valleys with bottomlands and terraces over them.

The habits of the river watercourses are determined by climatic conditions. Most rivers of the Altai territory are nourished by rain and snow. Subsoil water nour­ishment is rather weak, except for the rivers on the plains. The rivers of the highlands have snow, glacier and rain nourishment. The habits of the rivers change according to the timing of the thaw, rain fails, relief and bottom character. The beginning and the duration of flooding depends on the rapidness of thawing, the altitude of the area, and the speed of water flowing and the river length. During the warm season about 75% runoff for the year is carried out of the mountains. The shortest and the earliest floods are found in the rivers of Kulundinskaya Plain. Flooding in the upper reaches of the Kulunda basin lasts 10-12 days, but in the lower part of the basin it is longer. After floods the water levels in the rivers declines rapidly and the rivers grow shal­low. The lowest water level is observed in the middle or in the end of November and lasts 100 -140 days till the end of March or the middle of April. As the inflow of the surface waters stops, underground waters are spent. The rivers freeze up in October or November. This period lasts 110-170 days, and the ice is 250 - 280 cm thick. The rivers usually begin to open at the end of April.

In places where surface runoff is blocked, such as the low bottomlands, fliere are marshes. One can differentiate three types of marshes: bottom marshes, sur­face marshes and transitional marshes.

Hydrologists define the elements of annual water balance for the Altai territory in terms of: precipitation - 154 km³ (588 mm), evaporation - 105 km³ (399 mm), and runoff-49,4 km³. The common runoff includes the one from the Altai moun­tains (31,7 km³) and the runoff from plains (17,7 km³). The majority of the water flows out of mountain ridges to form the sources of the left tributaries of the Charish.

The rivers of the Altai territory are of great economic importance: there is shipping on the Ob, the Biya, the Katun and the Charish. Water supplies for the villages and towns, as well as irrigation for fields and pastures rely on the rivers. But, hydro - power is not widely used in energy production. A project of building a cascade of small hydro-electric power stations on the river Peschanaya is planned. All the rivers are suitable for fishing. A lot of tourist centers are situated on the banks of the rivers and lakes in picturesque locales.