Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs
===================================================================
diff -u -r4993 -r5010
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs	(.../SoilProfile2DSurfaceLineHelper.cs)	(revision 4993)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs	(.../SoilProfile2DSurfaceLineHelper.cs)	(revision 5010)
@@ -20,6 +20,7 @@
 // All rights reserved.
 
 using System;
+using Deltares.DamEngine.Data.Geometry;
 
 namespace Deltares.DamEngine.Data.Geotechnics;
 
@@ -66,9 +67,28 @@
     /// <param name="shift">The required shift of the geometry so it will fit the surface line</param>
     /// <returns></returns>
     public static SoilProfile2D CombineSurfaceLineWithSoilProfile2D(SurfaceLine2 surfaceLine, SoilProfile2D soilProfile2D,
-                                                             Soil defaultSoil, double shift)
+                                                                    Soil defaultSoil, double shift)
     {
         return null;
     }
-    
+
+    /// <summary>
+    /// Check if all the points of the surface line are above the bottom of the soil profile.
+    /// </summary>
+    /// <param name="surfaceLine"></param>
+    /// <param name="soilProfile2D"></param>
+    /// <returns></returns>
+    public static bool IsSurfaceLineAboveBottomSoilProfile2D(SurfaceLine2 surfaceLine, SoilProfile2D soilProfile2D)
+    {
+        double bottom = soilProfile2D.Geometry.Bottom;
+        foreach (GeometryPoint point in surfaceLine.Geometry.Points)
+        {
+            if (point.Z < bottom)
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
 }
\ No newline at end of file
Index: DamEngine/trunk/src/Deltares.DamEngine.TestHelpers/Factories/FactoryForSurfaceLines.cs
===================================================================
diff -u -r5007 -r5010
--- DamEngine/trunk/src/Deltares.DamEngine.TestHelpers/Factories/FactoryForSurfaceLines.cs	(.../FactoryForSurfaceLines.cs)	(revision 5007)
+++ DamEngine/trunk/src/Deltares.DamEngine.TestHelpers/Factories/FactoryForSurfaceLines.cs	(.../FactoryForSurfaceLines.cs)	(revision 5010)
@@ -787,58 +787,45 @@
         return surfaceLine;
     }
 
-    /// <summary>
-    /// Creates a surface line, that contains a dike and is fully above SurfaceLineWithDikeAndDitch. 
-    /// </summary>
-    /// <returns>surface line</returns>
-    public static SurfaceLine2 CreateSurfaceLineAboveSurfaceLineDikeAndDitch()
+    public static SurfaceLine2 CreateSurfaceLineDike(double offset = 0.0, string name = "SurfaceLineWithDikeAndDitch")
     {
         var surfaceLine = new SurfaceLine2
         {
-            Name = "AboveSurfaceLineWithDikeAndDitch",
+            Name = name,
             Geometry = new GeometryPointString(),
             CharacteristicPoints =
             {
                 GeometryMustContainPoint = true
             }
         };
 
-        surfaceLine.EnsurePointOfType(0.0, 5.0, CharacteristicPointType.SurfaceLevelOutside);
-        surfaceLine.EnsurePointOfType(10.0, 5.0, CharacteristicPointType.DikeToeAtRiver);
-        surfaceLine.EnsurePointOfType(34.5, 10.0, CharacteristicPointType.DikeTopAtRiver);
-        surfaceLine.EnsurePointOfType(40.5, 10.0, CharacteristicPointType.DikeTopAtPolder);
-        surfaceLine.EnsurePointOfType(50.5, 5.0, CharacteristicPointType.DikeToeAtPolder);
-        surfaceLine.EnsurePointOfType(75.0, 5.0, CharacteristicPointType.SurfaceLevelInside);
+        surfaceLine.EnsurePointOfType(0.0, offset + 0.0, CharacteristicPointType.SurfaceLevelOutside);
+        surfaceLine.EnsurePointOfType(10.0, offset + 0.0, CharacteristicPointType.DikeToeAtRiver);
+        surfaceLine.EnsurePointOfType(34.5, offset + 5.0, CharacteristicPointType.DikeTopAtRiver);
+        surfaceLine.EnsurePointOfType(40.5, offset + 5.0, CharacteristicPointType.DikeTopAtPolder);
+        surfaceLine.EnsurePointOfType(50.5, offset + 0.0, CharacteristicPointType.DikeToeAtPolder);
+        surfaceLine.EnsurePointOfType(75.0, offset + 0.0, CharacteristicPointType.SurfaceLevelInside);
 
         surfaceLine.Geometry.SyncCalcPoints();
         return surfaceLine;
     }
 
     /// <summary>
+    /// Creates a surface line, that contains a dike and is fully above SurfaceLineWithDikeAndDitch. 
+    /// </summary>
+    /// <returns>surface line</returns>
+    public static SurfaceLine2 CreateSurfaceLineAboveSurfaceLineDikeAndDitch()
+    {
+        return CreateSurfaceLineDike(5.0, "AboveSurfaceLineWithDikeAndDitch");
+    }
+
+    /// <summary>
     /// Creates a surface line, that contains a dike and is fully below SurfaceLineWithDikeAndDitch. 
     /// </summary>
     /// <returns>surface line</returns>
     public static SurfaceLine2 CreateSurfaceLineBelowSurfaceLineDikeAndDitch()
     {
-        var surfaceLine = new SurfaceLine2
-        {
-            Name = "BelowSurfaceLineWithDikeAndDitch",
-            Geometry = new GeometryPointString(),
-            CharacteristicPoints =
-            {
-                GeometryMustContainPoint = true
-            }
-        };
-
-        surfaceLine.EnsurePointOfType(0.0, -10.0, CharacteristicPointType.SurfaceLevelOutside);
-        surfaceLine.EnsurePointOfType(10.0, -10.0, CharacteristicPointType.DikeToeAtRiver);
-        surfaceLine.EnsurePointOfType(34.5, -5.0, CharacteristicPointType.DikeTopAtRiver);
-        surfaceLine.EnsurePointOfType(40.5, -5.0, CharacteristicPointType.DikeTopAtPolder);
-        surfaceLine.EnsurePointOfType(50.5, -10.0, CharacteristicPointType.DikeToeAtPolder);
-        surfaceLine.EnsurePointOfType(75.0, -10.0, CharacteristicPointType.SurfaceLevelInside);
-
-        surfaceLine.Geometry.SyncCalcPoints();
-        return surfaceLine;
+        return CreateSurfaceLineDike(-10.0, "AboveSurfaceLineWithDikeAndDitch");
     }
 
     /// <summary>
@@ -847,24 +834,6 @@
     /// <returns>surface line</returns>
     public static SurfaceLine2 CreateSurfaceLineCuttingSurfaceLineDikeAndDitch()
     {
-        var surfaceLine = new SurfaceLine2
-        {
-            Name = "BelowSurfaceLineWithDikeAndDitch",
-            Geometry = new GeometryPointString(),
-            CharacteristicPoints =
-            {
-                GeometryMustContainPoint = true
-            }
-        };
-
-        surfaceLine.EnsurePointOfType(0.0, -2.0, CharacteristicPointType.SurfaceLevelOutside);
-        surfaceLine.EnsurePointOfType(10.0, -2.0, CharacteristicPointType.DikeToeAtRiver);
-        surfaceLine.EnsurePointOfType(34.5, 7.0, CharacteristicPointType.DikeTopAtRiver);
-        surfaceLine.EnsurePointOfType(40.5, 7.0, CharacteristicPointType.DikeTopAtPolder);
-        surfaceLine.EnsurePointOfType(50.5, -2.0, CharacteristicPointType.DikeToeAtPolder);
-        surfaceLine.EnsurePointOfType(75.0, -2.0, CharacteristicPointType.SurfaceLevelInside);
-
-        surfaceLine.Geometry.SyncCalcPoints();
-        return surfaceLine;
+        return CreateSurfaceLineDike(-2.0, "AboveSurfaceLineWithDikeAndDitch");
     }
 }
\ No newline at end of file
Index: DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile2DSurfaceLineHelperTests.cs
===================================================================
diff -u -r4903 -r5010
--- DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile2DSurfaceLineHelperTests.cs	(.../SoilProfile2DSurfaceLineHelperTests.cs)	(revision 4903)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile2DSurfaceLineHelperTests.cs	(.../SoilProfile2DSurfaceLineHelperTests.cs)	(revision 5010)
@@ -120,6 +120,18 @@
         Assert.That(newSoilProfile2D.Surfaces, Has.Count.EqualTo(testCaseSurfaceLine.SurfaceCount));
     }
 
+    [Test]
+    [TestCase(0, true)] // Surface line is above the bottom of the soil profile
+    [TestCase(-10, true)] // Surface line is on and above the bottom of the soil profile
+    [TestCase(-12, false)] // Surface line is partly below the bottom of the soil profile
+    [TestCase(-20, false)] // Surface line is below the bottom of the soil profile
+    public void GivenSoilProfile2DWhenCallingIsSurfaceLineAboveBottomSoilProfile2DThenCorrectResponseIsReturned(double offset, bool response)
+    {
+        SurfaceLine2 surfaceLine = FactoryForSurfaceLines.CreateSurfaceLineDike(offset);
+        SoilProfile2D soilProfile2D = FactoryForSoilProfiles.CreateSoilProfile2DWithThreeLayers();
+        Assert.That(SoilProfile2DSurfaceLineHelper.IsSurfaceLineAboveBottomSoilProfile2D(surfaceLine, soilProfile2D), Is.EqualTo(response));
+    }
+
     /// <summary>
     /// Test case class for GivenSoilProfile2DWhenCombiningWithSurfaceLineThenCorrectNewSoilProfile2DIsCreated()
     /// </summary>
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs
===================================================================
diff -u -r5004 -r5010
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs	(.../MacroStabilityCommonHelperTests.cs)	(revision 5004)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelperTests.cs	(.../MacroStabilityCommonHelperTests.cs)	(revision 5010)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using System.Linq;
 using Deltares.DamEngine.Calculators.KernelWrappers.MacroStabilityCommon;
 using Deltares.DamEngine.Data.General;
@@ -269,6 +270,16 @@
         });
     }
 
+    [Test]
+    public void GivenSoilGeometryProbabilityWithSoilProfile2DAndSurfaceLinePartlyBelowSoilProfile2DBottomWhenCombiningThenExceptionIsRaised()
+    {
+        SoilGeometryProbability soilGeometryProbability = CreateSoilGeometryProbabilityWithSoilProfile2DWithSurfaceLineDitchDike();
+        SurfaceLine2 surfaceLine = FactoryForSurfaceLines.CreateSurfaceLineDike(-22.0, "PartlyBelowBottom");
+        // Now combine the soilGeometryProbability with the surfaceLine which should in an exception, because the surfaceLine 
+        // is partly below the bottom of the SoilProfile2D
+        Assert.Throws<InvalidOperationException>(() => { MacroStabilityCommonHelper.CombineSoilProfileWithSurfaceLine(soilGeometryProbability, surfaceLine, new Soil()); });
+    }
+
     private static SoilGeometryProbability CreateSoilGeometryProbabilityWithSoilProfile2DWithSurfaceLineDitchDike()
     {
         SoilGeometryProbability soilGeometryProbability = FactoryForSoilGeometryProbabilities.CreateSoilGeometryProbabilityWithSoilProfile1D();
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs
===================================================================
diff -u -r5008 -r5010
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs	(.../MacroStabilityCommonHelper.cs)	(revision 5008)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityCommonHelper.cs	(.../MacroStabilityCommonHelper.cs)	(revision 5010)
@@ -428,7 +428,11 @@
         {
             throw new ArgumentNullException(nameof(dikeEmbankmentSoil), @"DikeEmbankmentSoil cannot be null.");
         }
-
+        if (!SoilProfile2DSurfaceLineHelper.IsSurfaceLineAboveBottomSoilProfile2D(surfaceLine2, subSoilScenario.SoilProfile2D))
+        {
+            throw new InvalidOperationException(@"SurfaceLine is (partly) below the bottom of the SoilProfile2D.");
+        }
+        
         FitSoilProfile2DToSurfaceLine(subSoilScenario, surfaceLine2);
     }