has its source in the Tumuk Humak Mountains, at approximately 2° N, 54° W; it also absorbs the Koelebreek, among others. Numbers The Maroni basin is 68,700 km2; above the island Langatabbetje (110 km away from the mouth of the river) this area is 63,700 km2. Between 1952 and 1973, the average discharge near Langatabbetje was about 1,700 m3/second. The minimum was 95 m3/second, the maximum 6,550 m3/second. The estuary is approximately 90 km long; the average tidal range in the estuary is 2 m; in the dry season, the salt reaches about 40 km upstream to the town of Albina. The estimated potential hydro power for Suriname is between 1150 and 1250 megawatts. Exploration The Maroni is the most extensively studied of all the rivers in Suriname. In the 16th century, there were already ships exploring the estuary, by Lawrence Keymis, Thomas Masham, Antonio de Berrio and Adriaen Cabeliau and in the 17th century, by Harcourt, Fisher and De Vries. In the 18th century more extensive excursions took place, by Mentell, Patris, Le Blond and Heneman and in the 19th century by Zegelaar, Jules Crevaux, Coudreau, Ten Kate, Joost and others. Of importance in the 20th century were the Gonini and Tapanahony expeditions, and the Tumuk Humak and Southern Border Expeditions. From these arose the research of the Geologisch Mijnbouwkundige Dienst (GMD) and the Centraal Bureau voor Luchtkartering (CBL). References C.F.A. Bruijning und J. Voorhoeve (Ed.): Encyclopedie van Suriname. Amsterdam & Brussels 1977, B.V. Uitgeversmaatschappij Argus Elsevier, p. 256, 396–397; . Rivers of French Guiana Rivers of Suriname Rivers of France French Guiana–Suriname border International rivers of South America Sipaliwini District Border rivers