The valleys of the Modder, Reit and the lower Caledon contain rich alluvial deposits.
GRONINGEN, a town of Holland, capital of the province of the same name, at the confluence of the two canalized rivers the Drentsche Aa and the Hunse (which are continued to the Lauwers Zee as the Reit Diep), 16 m.
Besides the Reit Diep, there are the Ems Canal and the Damster Diep, connecting it with Delfzyl and the Dollart, the Kolonel's Diep with Leeuwarden, the Nord Willem's Canal with Assen and the south and the Stads-Canal south-east with the Ems. Hence steamers ply in all directions, and there is a regular service to Emden and the island of Borkum via Delfzyl, and via the Lauwers Zee to the island of Schiermonnikoog.
The chief tributaries of the Vaal (q.v.) wholly or partly within the province are, going from east to west, the Klip (this stream from near its source to its confluence with the Vaal divides the Free State from the Transvaal), the Wilge, Rhenoster, Vet, Modder and Reit.