diff -ruN freeciv.orig/common/map.c freeciv/common/map.c
--- freeciv.orig/common/map.c	Sun Jun 18 11:27:06 2000
+++ freeciv/common/map.c	Mon Jun 19 19:03:12 2000
@@ -570,6 +570,13 @@
 }
 
 /***************************************************************
+return flags (OCEAN/LAND/SWEETWATER/...) for given terrain type
+***************************************************************/
+enum terrain_flag terrain_get_flags (enum tile_terrain_type type) {
+  return get_tile_type (type)->flags;
+}
+
+/***************************************************************
 Check if terrain is ok for land units to be,
 infrastructure (transporters etc.) doesn't count
 
@@ -577,7 +584,11 @@
 but may change in future (T_ARCHIPELAGO, T_FJORD etc.)
 ***************************************************************/
 int is_land (int x, int y) {
+#if 1
   return (map_get_terrain(x,y) != T_OCEAN);
+#else
+  return (terrain_get_flags(map_get_terrain(x,y)) & TF_LAND);
+#endif
 }
 
 /***************************************************************
@@ -585,7 +596,29 @@
 infrastructure (cities etc.) doesn't count
 ***************************************************************/
 int is_ocean (int x, int y) {
+#if 1
   return (map_get_terrain(x,y) == T_OCEAN);
+#else
+  return (terrain_get_flags(map_get_terrain(x,y)) & TF_OCEAN);
+#endif
+}
+
+/***************************************************************
+Check if tile can supply water for irrigations
+***************************************************************/
+int has_sweetwater (int x, int y) {
+  enum tile_terrain_type t;
+  enum tile_special_type s;
+
+  t=map_get_terrain(x,y);
+#if 1
+  if ((t == T_OCEAN) || (t == T_RIVER)) return 1;
+#else
+  if (terrain_get_flags(t) & TF_SWEETWATER) return 1;
+#endif
+  s=map_get_special(x,y);
+  if ((s & S_RIVER) || (s & S_IRRIGATION)) return 1;
+  return 0;
 }
 
 /***************************************************************
diff -ruN freeciv.orig/common/map.h freeciv/common/map.h
--- freeciv.orig/common/map.h	Sat Jun 17 23:21:09 2000
+++ freeciv/common/map.h	Mon Jun 19 19:03:25 2000
@@ -219,8 +219,10 @@
 int is_special_close(int x, int y);
 int is_special_type_close(int x, int y, enum tile_special_type spe);
 int is_sea_usable(int x, int y);
+enum terrain_flag terrain_get_flags (enum tile_terrain_type type);
 int is_land (int x, int y);
 int is_ocean (int x, int y);
+int has_sweetwater (int x, int y);
 int get_tile_food_base(struct tile * ptile);
 int get_tile_shield_base(struct tile * ptile);
 int get_tile_trade_base(struct tile * ptile);
diff -ruN freeciv.orig/server/settlers.c freeciv/server/settlers.c
--- freeciv.orig/server/settlers.c	Wed Jun 14 13:18:04 2000
+++ freeciv/server/settlers.c	Mon Jun 19 18:53:39 2000
@@ -525,16 +525,8 @@
 **************************************************************************/
 static int is_wet(struct player *pplayer, int x, int y)
 {
-  enum tile_terrain_type t;
-  enum tile_special_type s;
-
   if (!pplayer->ai.control && !map_get_known(x, y, pplayer)) return 0;
-
-  t=map_get_terrain(x,y);
-  if (t == T_OCEAN || t == T_RIVER) return 1;
-  s=map_get_special(x,y);
-  if ((s & S_RIVER) || (s & S_IRRIGATION)) return 1;
-  return 0;
+  return has_sweetwater (x,y);
 }
 
 /**************************************************************************