Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PlLinesCreator.cs
===================================================================
diff -u -r4540 -r4934
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PlLinesCreator.cs	(.../PlLinesCreator.cs)	(revision 4540)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/PlLinesCreator/PlLinesCreator.cs	(.../PlLinesCreator.cs)	(revision 4934)
@@ -741,7 +741,7 @@
 
         GeometryPoint characteristicGeometryPoint = SurfaceLine.CharacteristicPoints.GetGeometryPoint(characteristicPointType);
         SoilProfile1D actualSoilProfile = GetSoilProfileBelowPoint(characteristicGeometryPoint.X);
-        double bottomLevel = actualSoilProfile.GetTopLevelOfHighestAquifer();
+        double bottomLevel = actualSoilProfile.GetHighestAquifer().TopLevel;
         double topLevel = characteristicGeometryPoint.Z;
         return topLevel - bottomLevel;
     }
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs
===================================================================
diff -u -r4928 -r4934
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 4928)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 4934)
@@ -38,7 +38,8 @@
     {
         BottomAquifer,
         TopLayerInBetweenAquiferCluster,
-        BottomLayerInBetweenAquiferCluster
+        BottomLayerInBetweenAquiferCluster,
+        HighestAquifer
     }
 
     private const double epsilon = 1e-9;
@@ -74,17 +75,7 @@
         if (plLine != null && !IsBelowSoilProfile(soilProfile1D, plLine))
         {
             waternet.PhreaticLine = CreateLine<PhreaticLine>(plLine, headLine1Name);
-            WaternetLine waternetLine;
-            if (pressureType == IntrusionVerticalWaterPressureType.Linear)
-            {
-                List<Point2D> coordinates = surfaceLine.Points.Select(point => new Point2D(point.X, point.Z)).ToList();
-                waternetLine = CreateWaternetLine(coordinates);
-            }
-            else
-            {
-                double level = soilProfile1D.GetLayerAt(headLine.GetMinZ()).BottomLevel;
-                waternetLine = CreateWaternetLine(level, xLeft, xRight);
-            }
+            WaternetLine waternetLine = CreateWaternetLineForPhreaticLine(soilProfile1D, surfaceLine, headLine, xLeft, xRight, pressureType);
             waternetLine.Name = waternetLine1Name;
             waternetLine.HeadLine = headLine;
             waternetLine.HeadLine.SyncCalcPoints();
@@ -395,7 +386,7 @@
             if (currentAquifer != null)
             {
                 previousAquiferLayer = currentAquifer;
-                coordinates.Add(layerType is LayerType.BottomAquifer or LayerType.TopLayerInBetweenAquiferCluster ? new Point2D(xCoordinate, currentAquifer.TopLevel) : new Point2D(xCoordinate, currentAquifer.BottomLevel));
+                coordinates.Add(layerType is LayerType.BottomLayerInBetweenAquiferCluster? new Point2D(xCoordinate, currentAquifer.BottomLevel) : new Point2D(xCoordinate, currentAquifer.TopLevel));
             }
         }
 
@@ -425,20 +416,85 @@
                 return soilProfile1D.GetInBetweenAquiferClusters[indexInBetweenAquifer].Item1;
             case LayerType.BottomLayerInBetweenAquiferCluster:
                 return soilProfile1D.GetInBetweenAquiferClusters[indexInBetweenAquifer].Item2;
+            case LayerType.HighestAquifer:
+                return soilProfile1D.GetHighestAquifer();
         }
 
         return null;
     }
 
+    /// <summary>
+    /// The position of the waternet line associated to the phreatic line depends on the water pressure type:
+    /// - For DAM Standard type, this line lies on the bottom of the soil layers “in which the phreatic plane lies”.
+    /// - For Linear type, it is the surface line.
+    /// - For Hydrostatic type, it is the top of the highest aquifer.
+    /// </summary>
+    /// <param name="soilProfile1D"></param>
+    /// <param name="surfaceLine"></param>
+    /// <param name="phreaticLine"></param>
+    /// <param name="xLeft"></param>
+    /// <param name="xRight"></param>
+    /// <param name="pressureType"></param>
+    /// <returns></returns>
+    private static WaternetLine CreateWaternetLineForPhreaticLine(SoilProfile1D soilProfile1D, GeometryPointString surfaceLine, HeadLine phreaticLine, double xLeft, double xRight, IntrusionVerticalWaterPressureType? pressureType)
+    {
+        if (pressureType == IntrusionVerticalWaterPressureType.Linear)
+        {
+            List<Point2D> coordinates = surfaceLine.Points.Select(point => new Point2D(point.X, point.Z)).ToList();
+            return CreateWaternetLine(coordinates);
+        }
+
+        if (pressureType == IntrusionVerticalWaterPressureType.HydroStatic)
+        {
+            double topAquiferLevel = soilProfile1D.GetHighestAquifer().TopLevel;
+            return CreateWaternetLine(topAquiferLevel, xLeft, xRight);
+        }
+        
+        double level = soilProfile1D.GetLayerAt(phreaticLine.GetMinZ()).BottomLevel;
+        return CreateWaternetLine(level, xLeft, xRight);
+        
+    }
+
+    /// <summary>
+    /// The position of the waternet line associated to the phreatic line depends on the water pressure type:
+    /// - For DAM Standard type, this line lies on the bottom of the soil layers “in which the phreatic plane lies”.
+    /// - For Linear type, it is the surface line.
+    /// - For Hydrostatic type, it is the top of the highest aquifer.
+    /// </summary>
+    /// <param name="soilProfile2D"></param>
+    /// <param name="plLine"></param>
+    /// <param name="pressureType"></param>
+    /// <returns></returns>
+    /// <exception cref="ArgumentOutOfRangeException"></exception>
     private static WaternetLine CreateWaternetLineForPhreaticLine(SoilProfile2D soilProfile2D, PlLine plLine, IntrusionVerticalWaterPressureType? pressureType)
     {
-        if (pressureType != IntrusionVerticalWaterPressureType.Linear)
+        switch (pressureType)
         {
-            return CreateWaternetLineForPhreaticLineForDamStandard(soilProfile2D, plLine);
+            case IntrusionVerticalWaterPressureType.HydroStatic:
+            {
+                double[] xCoordinates = DetermineAllXCoordinatesOfSoilProfile(soilProfile2D);
+                Point2D[] highestAquiferCoordinates = DetermineLayerBoundaryCoordinates(LayerType.HighestAquifer, xCoordinates, soilProfile2D).ToArray();
+                return CreateWaternetLine(highestAquiferCoordinates);
+            }
+            case IntrusionVerticalWaterPressureType.Linear:
+            {
+                List<Point2D> coordinates = soilProfile2D.Geometry.SurfaceLine.Points.Select(point => new Point2D(point.X, point.Z)).ToList();
+                return CreateWaternetLine(coordinates);
+            }
+            case IntrusionVerticalWaterPressureType.Standard:
+                break;
+            case IntrusionVerticalWaterPressureType.FullHydroStatic:
+                break;
+            case IntrusionVerticalWaterPressureType.SemiTimeDependent:
+                break;
+            case null:
+                break;
+            default:
+                throw new ArgumentOutOfRangeException(nameof(pressureType), pressureType, null);
         }
 
-        List<Point2D> coordinates = soilProfile2D.Geometry.SurfaceLine.Points.Select(point => new Point2D(point.X, point.Z)).ToList();
-        return CreateWaternetLine(coordinates);
+        return CreateWaternetLineForPhreaticLineForDamStandard(soilProfile2D, plLine);
+        
     }
 
     /// <summary>
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverterTests.cs
===================================================================
diff -u -r4928 -r4934
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverterTests.cs	(.../PlLinesToWaternetConverterTests.cs)	(revision 4928)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverterTests.cs	(.../PlLinesToWaternetConverterTests.cs)	(revision 4934)
@@ -82,6 +82,7 @@
 
     [TestCase(IntrusionVerticalWaterPressureType.Standard, -2.110)]
     [TestCase(IntrusionVerticalWaterPressureType.Linear, 1.212)]
+    [TestCase(IntrusionVerticalWaterPressureType.HydroStatic, -2.110)]
     public void TestConvertPlLinesToWaternet_1DSoilProfile(IntrusionVerticalWaterPressureType? pressureType, double levelWaternetPl1)
     {
         PlLines plLines = CreatePlLinesForTest();
@@ -442,6 +443,7 @@
     /// </code>
     [TestCase(IntrusionVerticalWaterPressureType.Standard, -9.999)]
     [TestCase(IntrusionVerticalWaterPressureType.Linear, 0)]
+    [TestCase(IntrusionVerticalWaterPressureType.HydroStatic, -9.999)]
     public void CreateWaternetBasedOnPlLines_ValidPLLinesAndSoilProfile2DWithContinuousInBetweenAquiferLayerConsistOfOnePart_ReturnsExpectedWaternet(IntrusionVerticalWaterPressureType? pressureType, double levelWaternetPl1)
     {
         // Setup
Index: DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile1DTests.cs
===================================================================
diff -u -r4927 -r4934
--- DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile1DTests.cs	(.../SoilProfile1DTests.cs)	(revision 4927)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data.Tests/Geotechnics/SoilProfile1DTests.cs	(.../SoilProfile1DTests.cs)	(revision 4934)
@@ -44,6 +44,8 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer3));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer4));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer4));
         });
@@ -54,6 +56,8 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer5));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer6));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer5));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer6));
         });
@@ -64,6 +68,8 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer1));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer2));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer1));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer2));
         });
@@ -74,6 +80,7 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer(), Is.Null);
             Assert.That(soilProfile1D.BottomAquiferLayer, Is.Null);
         });
 
@@ -83,6 +90,8 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer3));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer4));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer4));
         });
@@ -93,6 +102,8 @@
         {
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters, Is.Empty);
             Assert.That(soilProfile1D.InBetweenAquiferLayer, Is.Null);
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer4));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer5));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer4));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer5));
         });
@@ -108,6 +119,8 @@
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters[1].Item2.BottomLevel, Is.EqualTo(topLevelLayer5));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer2));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer3));
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer2));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer6));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(bottomLevelLayer6));
         });
@@ -121,6 +134,8 @@
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters[0].Item2.BottomLevel, Is.EqualTo(topLevelLayer5));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer2));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer3));
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer2));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer6));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(bottomLevelLayer6));
         });
@@ -134,6 +149,8 @@
             Assert.That(soilProfile1D.GetInBetweenAquiferClusters[0].Item2.BottomLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer2));
             Assert.That(soilProfile1D.InBetweenAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer3));
+            Assert.That(soilProfile1D.GetHighestAquifer().TopLevel, Is.EqualTo(topLevelLayer2));
+            Assert.That(soilProfile1D.GetHighestAquifer().BottomLevel, Is.EqualTo(topLevelLayer3));
             Assert.That(soilProfile1D.BottomAquiferLayer.TopLevel, Is.EqualTo(topLevelLayer4));
             Assert.That(soilProfile1D.BottomAquiferLayer.BottomLevel, Is.EqualTo(topLevelLayer5));
         });
Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile1D.cs
===================================================================
diff -u -r4927 -r4934
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile1D.cs	(.../SoilProfile1D.cs)	(revision 4927)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile1D.cs	(.../SoilProfile1D.cs)	(revision 4934)
@@ -512,19 +512,19 @@
     }
 
     /// <summary>
-    /// Gets the top level of highest aquifer.
+    /// Gets the highest aquifer.
     /// </summary>
     /// <returns></returns>
-    public double GetTopLevelOfHighestAquifer()
+    public SoilLayer1D GetHighestAquifer()
     {
-        double topLevel;
+        SoilLayer1D topLevel;
         if (InBetweenAquiferLayer != null)
         {
-            topLevel = InBetweenAquiferLayer.TopLevel;
+            topLevel = InBetweenAquiferLayer;
         }
         else
         {
-            topLevel = BottomAquiferLayer.TopLevel;
+            topLevel = BottomAquiferLayer;
         }
 
         return topLevel;