Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs
===================================================================
diff -u -r5111 -r5258
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs	(.../GeometryData.cs)	(revision 5111)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geometry/GeometryData.cs	(.../GeometryData.cs)	(revision 5258)
@@ -340,7 +340,7 @@
     /// <param name="curve"></param>
     /// <param name="boundaryCurves"></param>
     /// <param name="excludedCurves"></param>
-    /// <returns></returns>
+    /// <returns>Curve</returns>
     private GeometryCurve GetNextTopCurve(GeometryCurve curve, List<GeometryCurve> boundaryCurves,
                                           List<GeometryCurve> excludedCurves)
     {
@@ -350,18 +350,11 @@
             return null;
         }
 
-        foreach (GeometryCurve geometryCurve in boundaryCurves)
-        {
-            if (geometryCurve != curve && !excludedCurves.Contains(geometryCurve))
-            {
-                if (AreConnected(curve, geometryCurve))
-                {
-                    return geometryCurve;
-                }
-            }
-        }
-
-        return null;
+        IEnumerable<GeometryCurve> includedCurves = boundaryCurves.Where(geometryCurve => geometryCurve != curve && !excludedCurves.Contains(geometryCurve));
+        IEnumerable<GeometryCurve> connectedCurves = includedCurves.Where(geometryCurve => AreConnected(curve, geometryCurve));
+        IEnumerable<GeometryCurve> connectedCurvesOnRightSide = connectedCurves.Where(geometryCurve => IsOnLeftSideOf(curve, geometryCurve));
+        GeometryCurve topConnectedCurve = connectedCurvesOnRightSide.MaxBy(c => c.HeadPoint.Z + c.EndPoint.Z);
+        return topConnectedCurve;
     }
 
     /// <summary>
@@ -493,13 +486,29 @@
         return false;
     }
 
-    private bool AreConnected(GeometryCurve curve1, GeometryCurve curve2)
+    private static bool AreConnected(GeometryCurve curve1, GeometryCurve curve2)
     {
-        return (curve1.HeadPoint == curve2.HeadPoint || curve1.HeadPoint == curve2.EndPoint ||
-                curve1.EndPoint == curve2.HeadPoint || curve1.EndPoint == curve2.EndPoint);
+        return curve1.HeadPoint.LocationEquals(curve2.HeadPoint) || 
+               curve1.HeadPoint.LocationEquals(curve2.EndPoint) ||
+               curve1.EndPoint.LocationEquals(curve2.HeadPoint) || 
+               curve1.EndPoint.LocationEquals(curve2.EndPoint);
     }
-
+    
     /// <summary>
+    /// Checks if curve1 is on the left side of curve2
+    /// </summary>
+    /// <param name="curve1"></param>
+    /// <param name="curve2"></param>
+    /// <returns>True when curve1 is on the left side of curve2</returns>
+    private static bool IsOnLeftSideOf(GeometryCurve curve1, GeometryCurve curve2)
+    {
+        return curve1.HeadPoint.X.IsLessThanOrEqualTo(curve2.HeadPoint.X) && 
+               curve1.HeadPoint.X.IsLessThanOrEqualTo(curve2.EndPoint.X) &&
+               curve1.EndPoint.X.IsLessThanOrEqualTo(curve2.HeadPoint.X) &&
+               curve1.EndPoint.X.IsLessThanOrEqualTo(curve2.EndPoint.X);
+    }
+        
+    /// <summary>
     /// Updates the line at the top of the geometry
     /// </summary>
     private void UpdateSurfaceLine()