. The earth and its inhabitants ... Geography. THE BALTIC PROVINCES. 229 drainage is to Lake Peipus, and tbrough the Narova to the Gulf of Finhmd. In the west the Pernau, Livonian Aa, Dvina, and Kurhmd Aa flow to the Gulf of Riga, while the Windau and the less important streams full into the Baltic. None of them are of any size except the Dvina (Diina of the Germans, Daugava of the Letts, Zapadnaya Dvina, or Western Dvina, of the Russians), which discharges about 18,000 cubic feet per second, draining a total area of 30,000 square miles, where there is an approximate annual rainfall of 20 inch
. The earth and its inhabitants ... Geography. THE BALTIC PROVINCES. 229 drainage is to Lake Peipus, and tbrough the Narova to the Gulf of Finhmd. In the west the Pernau, Livonian Aa, Dvina, and Kurhmd Aa flow to the Gulf of Riga, while the Windau and the less important streams full into the Baltic. None of them are of any size except the Dvina (Diina of the Germans, Daugava of the Letts, Zapadnaya Dvina, or Western Dvina, of the Russians), which discharges about 18,000 cubic feet per second, draining a total area of 30,000 square miles, where there is an approximate annual rainfall of 20 inches. Gathering the waters of the western and ^, IT -ij • t Fis:. 110.—Parallel Hills of Dorp at. southern Valdai slopes, the ° ^ , __^ ^ Scale 1: 300,000. Dvina flows first south-west, below Vitebsk trending Avest and north-west, its low and marshy banks in many places retaining the traces of former beds. According to the pre- sent relief of the land its natural course would be southwards to the Dnieper. But the changes of level, or the erosions produced in the course of ages, have enabled it to open a passage between the Silurian plateaux of Livonia and Kurland, and thus reach the Baltic. In the rocky regions the navi- gation is seriously obstructed by rapids, giving a total fall of about 174 feet in 87 miles, but very unequally distri- buted. Below Riga the river ramifies into several branches, winding through an old lacustrine bed for- merly separated from the sea by a range of dunes. Little Dvina, Red Dvina, Old Dvina, and similar names recall the vagaries of the stream, and sundry structures—forts, mills, dykes, and the like—are figured on the maps, now to the north, now to the south of the ship channel. Near its mouth it is joined by the Kurland Aa, known in its lower courses as the Bolder Aa. About 4 miles from the junction the Aa has recently thrown oiï a branch directly to the Gulf of Riga, and it may thus sooner or later cease to be an affluent of the Dv
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgeography, bookyear1883
