Index: src/water_cmd.cpp
===================================================================
--- src/water_cmd.cpp	(revision 27194)
+++ src/water_cmd.cpp	(working copy)
@@ -419,6 +419,7 @@
 		if (IsTileType(tile, MP_WATER) && (!IsTileOwner(tile, OWNER_WATER) || wc == WATER_CLASS_SEA)) continue;
 
 		bool water = IsWaterTile(tile);
+		bool river = GetWaterClass(tile) == WATER_CLASS_RIVER;
 		ret = DoCommand(tile, 0, 0, flags | DC_FORCE_CLEAR_TILE, CMD_LANDSCAPE_CLEAR);
 		if (ret.Failed()) return ret;
 
@@ -442,6 +443,7 @@
 					/* FALL THROUGH */
 
 				default:
+					if (river) SB(_me[tile].m6, 0, 0, 1);
 					MakeCanal(tile, _current_company, Random());
 					if (Company::IsValidID(_current_company)) {
 						Company::Get(_current_company)->infrastructure.water++;