All of Romania's rivers and streams drain to the Black Sea. Except for the minor streams that rise on the eastern slopes of the hills near the sea and flow directly into it, all join the Danube River. Those flowing southward and southeastward from the Transylvanian Alps drain to the Danube directly. Those flowing northward and eastward from Moldavia and Bukovina reach the Danube by way of the Prut River. Most of the Transylvanian streams draining to the north and west flow to the Tisza River, which joins the Danube in Yugoslavia, north of Belgrade.

Romanian tourist literature states that the country has 2,500 lakes, but most are small, and lakes occupy only about 1 percent of the surface area. The largest lakes are along the Danube River and the Black Sea coast. Some of those along the coast are open to the sea and contain salt sea water. These and a few of the fresh water lakes are commercially important for their fish. The many smaller ones scattered throughout the mountains are usually glacial in origin and add much to the beauty of the resort areas.

The Danube drains a basin of 315,000 square miles that extends eastward from the Black Forest in the Federal Republic of Germany (West Germany) and includes a portion of the southwestern Soviet Union. It is about 1,775 miles long, including the 900 miles in or adjacent to Romania, and is fed by more than 300 tributaries, from which it collects an average of about 285,000 cubic feet per minute to discharge into the Black Sea. Much of the Danube delta and a band of up to twenty miles wide along most of the length of the river from the delta to the so-called Iron Gate—where it has cut a deep gorge through the mountains along the Yugoslav border—is marshland.

For descriptive purposes the river is customarily divided into three sections; most of the portion in Romania—from the Iron Gate to the Black Sea—is its lower course. The northern bank of this course, on the Romanian side, is low, flat marshland and, as it approaches its delta, it divides into a number of channels. It also forms several lakes, some of them quite large. At its delta it divides into three major and several minor branches. The delta has an area of about 1,000 square miles and grows steadily as the river deposits some 2 billion cubic feet of sediment into the sea annually.

Climate

The climate is continental and is characterized by hot summers and cold winters. Typical weather and precipitation result from the high pressure systems that predominate over European Soviet Union and north-central Asia. Southern Europe's Mediterranean weather and western European maritime systems occasionally extend into the area but not frequently, and they prevail only for short periods. Winters are long, and the months from November through March tend to be cold and cloudy, with frequent fog and snow. Although summers may be hot, they are sunny, and the humidity is usually at comfortable levels.

Precipitation ranges from fifteen to fifty inches; the countrywide average is about twenty-eight inches. Dobruja, along the lower Danube River and adjacent to the Black Sea coast, averages the least, followed by the lowlands of Moldavia and southernmost Walachia, which usually receive less than twenty inches. The remaining lowlands of the country and the Transylvanian plateau average between about twenty and thirty-two inches. Bucharest receives about twenty-three inches. In all of the agricultural regions the heaviest precipitation, most of it from thunderstorms and showers, occurs during the summer growing season when it is of maximum benefit to crops and vegetation.

Scattered areas in the Transylvanian Alps and in the other mountains of the northern and western parts of the country receive more than fifty inches annually. Foothills on all exposures also get more than the country average. Western exposures benefit from the generally eastward movement of weather systems; southern and eastern slopes benefit from the clockwise circulation around the high-pressure systems that are characteristic of the continental climate.

January is the coldest month; July, the warmest. Bucharest, located inland on the southern lowland, is one of the warmest points in summer and has one of the widest variations between average temperatures of the extreme hot and cold months. Its average January temperature is about 27° F, and in July it is 73° F. Summer averages are about the same at other places in the eastern lowlands and along the Black Sea, but the moderating effect of winds off the sea makes for slightly warmer winters in those areas. Hilly and mountainous sections of the country are cooler but have less variation between winter and summer extremes.

Nowhere in the country is the climate the deciding factor on the distribution of population. There are no points where summer temperatures are oppressively high or winter temperatures are intolerably low. Rainfall is adequate in all regions and, in the lower Danube River area where it might be considered the most nearly marginal, marshes and poorly drained terrain are more of a problem than is lack of rainfall.