Nearly all of the precipitation that falls on Albania drains into the rivers and reaches the coast without even leaving the country. In the north, only one small stream escapes Albania. In the south, an even smaller rivulet drains into Greece. Because the topographical divide is east of the Albanian border with its neighbors, a considerable amount of water from other countries drains through Albania. An extensive portion of the basin of the Drini i Bardh� River, called Beli Drim by Serbs, basin is in the Kosovo area, across Albania's northeastern border. The three eastern lakes that Albania shares with its neighboring countries, as well as the streams that flow into them, drain into the Drini i Zi. The watershed divide in the south also dips nearly seventyfive kilometers into Greece at one point. Several tributaries of the Vjos� River rise in that area.

With the exception of the Drini i Zi, which flows northward and drains nearly the entire eastern border region before it turns westward to the sea, most of the rivers in northern and central Albania flow fairly directly westward to the sea. In the process, they cut through the ridges rather than flow around them. This apparent geological impossibility occurs because the highlands originally were lifted without much folding. The streams came into existence at that time. The compression and folding of the plateau into ridges occurred later. The folding process was rapid enough in many instances to dam the rivers temporarily. The resulting lakes existed until their downstream channels became wide enough to drain them. This sequence created the many interior basins that are typically a part of the Albanian landform. During the lifetime of the temporary lakes, enough sediment was deposited in them to form the basis for fertile soils. Folding was rarely rapid enough to force the streams into 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 economic value of the streams. They erode the mountains and deposit the sediment that created the lowlands and continues to augment them, but the rivers flood when there is local rainfall. When the lands are parched and need irrigation, the rivers usually are dry. Their violence when they are full makes them difficult to control, and they are unnavigable. The Bun� River is an exception. It is dredged between Shkod�r and the Adriatic Sea and can be negotiated by small ships. In contrast to their history of holding fast to their courses in the mountains, the rivers constantly change channels on the lower plains, making waste of much of the land they create.

The Drin River is the largest and most constant stream. 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 282 kilometers, it drains nearly 5,957 square kilometers 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 encompasses about 15,540 square kilometers.

The Seman and Vjos� are the only other rivers that are more than 160 kilometers long and have basins larger than 2,600 square kilometers. 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 length. This variable nature also characterizes 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.

Although the sediment carried by the mountain torrents continues to be deposited, new deposits delay exploitation. Stream channels rise as silt is deposited in them and eventually become higher than the surrounding terrain. Shifting channels frustrate development in many areas. Old channels become barriers to proper drainage and create swamps or marshlands. It is difficult to build roads or railroads across the lowlands or otherwise use the land.

Irrigation has been accomplished on a small scale by Albanian peasants for many years. Large irrigation projects were not completed, however, until after World War II, including the Vjos�-Levan-Fier irrigation canal, with an irrigation capacity of 15,000 hectares, and the reservoir at Than� reservoir, in Lushnj� District, with an irrigation capacity of 35,100 hectares. In 1986 nearly 400,000 hectares of land, or 56 percent of the total cultivated area, were under irrigation, compared with 29,000 hectares, or 10 percent of the total cultivated area, in 1938.