Название | Area Handbook for Albania |
---|---|
Автор произведения | Stephen Peters |
Жанр | Языкознание |
Серия | |
Издательство | Языкознание |
Год выпуска | 0 |
isbn | 4057664624659 |
Rainfall in the upland mountain ranges is higher. Adequate records are not available, and estimates vary widely, but annual averages are probably about 70 inches and are as high as 100 inches in some northern areas. The seasonal variation is not quite as great as in the coastal area, with the most nearly even distribution in the north, largely because of summer thunderstorms.
The higher inland mountains receive less precipitation than the intermediate uplands. Terrain differences cause wide local variations, but the seasonal distribution is the most consistent of any area. In the northern mountains, for example, the months that usually have the highest averages are November and June.
DRAINAGE
All but a very small portion of the precipitation drains through the rivers to the coastline without leaving the country. With the exception of a few insignificant trickles, only one small stream in the northern part of the country escapes Albania. In the south an even smaller rivulet drains into Greece. As the divide is on the eastern side of the borders with Yugoslavia and Greece, however, a considerable amount of water from those countries drains through Albania. A quite extensive portion of the White Drin River basin is in the Kosovo area across the northeastern Yugoslav border. The three lakes shared with Yugoslavia and Greece, as well as all the streams that flow into them, drain into the Drin River. The watershed divide in the south also dips nearly forty miles into Greece at one point. Several tributaries of the Vijose River rise in that area (see fig. 4).
Figure 4. Rivers and Lakes in Albania
With the exception of the Drin River, which flows northward and drains nearly the entire eastern border region before it turns westward to the sea, most of the rivers in the northern and central parts of the country flow much more directly westward to the sea. In the process they cut through the ridges rather than flowing around them. This apparent impossibility came about because the highlands were originally lifted without much folding. The streams came into existence at that time and antedate the ridges because the compression and folding of the plateau occurred later. The folding process was rapid enough in many instances to block the rivers temporarily, forming lakes that existed until the downstream channel was cut sufficiently to drain them. This sequence created the many interior basins that are typically a part of the landforms. During the lifetimes of the temporary lakes enough sediment was deposited in them to form the basis for fertile soils. Folding was only infrequently rapid enough to force the streams to radically different channels.
The precipitous fall from higher elevations and the highly irregular seasonal flow patterns that are characteristic of nearly all streams in the country reduce the immediate value of the streams. They erode the mountains and deposit the sediment that created, and continues to add to, the lowlands, but the rivers flood during the seasons when there is local rainfall. When the lands are parched and need irrigation, the rivers are usually dry. Their violence makes them difficult to control, and they are unnavigable. The Buene is an exception. It is dredged between Shkoder and the Adriatic and is navigable for small ships. In contrast to their histories of holding fast to their courses in the mountains, the rivers have constantly changed channels on the lower plains, making wastes of much of the land they have created.
The Drin River is the largest and most constant stream (see table 2). Fed by melting snows from the northern and eastern mountains and by the more evenly distributed seasonal precipitation of that area, its flow does not have the extreme variations characteristic of nearly all other rivers in the country. Its normal flow varies seasonally by only about one-third. Along its length of about 175 miles it drains nearly 2,300 square miles within Albania. As it also collects from the Adriatic portion of the Kosovo watershed and the three border lakes (Lake Prespa drains to Lake Ohrid via an underground stream), its total basin is around 6,000 square miles.
The Seman and Vijose are the only other rivers that are more than 100 miles in length and have basins larger than 1,000 square miles. These rivers drain the southern regions and, reflecting the seasonal distribution of rainfall, are torrents in winter and nearly dry in the summer, in spite of their relatively long lengths. This is also the case with the many shorter streams. In the summer most of them carry less than a tenth of their winter averages, if they are not altogether dry.
Table 2. Drainage Basins in Albania
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