Index: src/water_cmd.cpp
===================================================================
--- src/water_cmd.cpp	(revision 27198)
+++ src/water_cmd.cpp	(working copy)
@@ -491,7 +491,9 @@
 					Company::Get(owner)->infrastructure.water--;
 					DirtyCompanyInfrastructureWindows(owner);
 				}
+				bool river = HasTileWaterClass(tile) && GetWaterClass(tile) == WATER_CLASS_RIVER;
 				DoClearSquare(tile);
+				if (river) MakeRiver(tile, Random());
 				MarkCanalsAndRiversAroundDirty(tile);
 			}