ZWOLLE, the capital of the province of Overysel, Holland, on the Zwarte Water, and a junction station 242 m.
It is the centre of the whole northern and eastern canal systems, and by means of the short canal, the Willemsvaart, which joins the Zwarte Water and the Ysel, has regular steamboat communication with Kampen and Amsterdam.
Into the Zuider Zee there also flow the Kuinder, the Zwarte Water, with its tributary the Vecht, and the Eem.
As a matter of course, the streams are also turned to account in connexion with the canal system - the Dommel, Berkel, Vecht, Regge, Holland Ysel, Gouwe, Rotte, Schie, Spaarne, Zaan, Amstel, Dieze, Amer, Mark, Zwarte Water, Kuinder and the numerous Aas in Drente and Groningen being the most important in this respect.
Thus in Overysel, in addition to the canals already mentioned, the Dedemsvaart connects the Vecht with the Zwarte Water near Hasselt; in Drente the Smildervaart and Drentsche Hoofdvaart unites Assen with Meppel, and receives on the eastern side the drainage canals of the Drente fens, namely, the Orange canal and the Hoogeveen Vaart (1850-1860; 1880-1893).
The southern streams are all collected at two points on the southern borders, namely, at Meppel and Koevorden, whence they communicate with the Zwarte Water and the Vecht respectively by means of the Meppeler Diep and the Koevorden canal.