Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io.Tests/IoDamMStabDocSeriliazerTests.cs
===================================================================
diff -u -r3138 -r3141
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io.Tests/IoDamMStabDocSeriliazerTests.cs	(.../IoDamMStabDocSeriliazerTests.cs)	(revision 3138)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io.Tests/IoDamMStabDocSeriliazerTests.cs	(.../IoDamMStabDocSeriliazerTests.cs)	(revision 3141)
@@ -55,6 +55,9 @@
         private IoMStabDamDoc CreateMStabDamDocExample()
         {
             var ioMStabDamDoc = new IoMStabDamDoc();
+            const double xLeftBoundary = 1.0;
+            const double xRightBoundary = 15.00;
+            const double yDeep = -100.0;
 
             // Geometry Creation Options
             ioMStabDamDoc.MStabInput.GeometryCreationOptions.MaterialForDike = "DikeMaterial";
@@ -72,7 +75,7 @@
             // SurfaceLine
             ioMStabDamDoc.MStabInput.SurfaceLine.Add(new IoGeometryPoint()
             {
-                X = 1.0,
+                X = xLeftBoundary,
                 Y = 1.5
             });
             ioMStabDamDoc.MStabInput.SurfaceLine.Add(new IoGeometryPoint()
@@ -107,14 +110,14 @@
             });
             ioMStabDamDoc.MStabInput.SurfaceLine.Add(new IoGeometryPoint()
             {
-                X = 15.0,
+                X = xRightBoundary,
                 Y = 0.5
             });
 
             // Characteristic Points
             ioMStabDamDoc.MStabInput.CharacteristicPoints.Add(new IoCharacteristicPoint()
             {
-                X = 1.0,
+                X = xLeftBoundary,
                 Y = 1.5,
                 CharacteristicPointType = CharacteristicPointType.SurfaceLevelOutside
             });
@@ -144,11 +147,67 @@
             });
             ioMStabDamDoc.MStabInput.CharacteristicPoints.Add(new IoCharacteristicPoint()
             {
-                X = 15.0,
+                X = xRightBoundary,
                 Y = 0.5,
                 CharacteristicPointType = CharacteristicPointType.SurfaceLevelInside
             });
 
+            // PL-Lines
+            var pl1 = new IoPlLine();
+            pl1.IsPhreatic = true;
+            pl1.BoundaryLayer = 1;
+            pl1.Points.Add(new IoGeometryPoint()
+            {
+                X = xLeftBoundary,
+                Y = -1.0
+            });
+            pl1.Points.Add(new IoGeometryPoint()
+            {
+                X = 0.5 * (xRightBoundary + xLeftBoundary),
+                Y = -2.0
+            });
+            pl1.Points.Add(new IoGeometryPoint()
+            {
+                X = xRightBoundary,
+                Y = -1.5
+            });
+            ioMStabDamDoc.MStabInput.ExternalPlLines.Add(pl1);
+
+            var pl2 = new IoPlLine();
+            pl2.IsPhreatic = false;
+            pl2.BoundaryLayer = 2;
+            pl2.Points.Add(new IoGeometryPoint()
+            {
+                X = xLeftBoundary,
+                Y = yDeep
+            });
+            pl1.Points.Add(new IoGeometryPoint()
+            {
+                X = xRightBoundary,
+                Y = yDeep
+            });
+            ioMStabDamDoc.MStabInput.ExternalPlLines.Add(pl2);
+
+            var pl3 = new IoPlLine();
+            pl3.IsPhreatic = false;
+            pl3.BoundaryLayer = 1;
+            pl3.Points.Add(new IoGeometryPoint()
+            {
+                X = xLeftBoundary,
+                Y = yDeep
+            });
+            pl1.Points.Add(new IoGeometryPoint()
+            {
+                X = xRightBoundary,
+                Y = yDeep
+            });
+            ioMStabDamDoc.MStabInput.ExternalPlLines.Add(pl3);
+
+            var pl4 = new IoPlLine();
+            pl4.IsPhreatic = false;
+            pl4.BoundaryLayer = 0;
+            ioMStabDamDoc.MStabInput.ExternalPlLines.Add(pl4);
+
             return ioMStabDamDoc;
         }
     }
Index: DamTools/LayerOnSlopeTool/trunk/xsd/DamMStabDefinitions.xsd
===================================================================
diff -u -r3136 -r3141
--- DamTools/LayerOnSlopeTool/trunk/xsd/DamMStabDefinitions.xsd	(.../DamMStabDefinitions.xsd)	(revision 3136)
+++ DamTools/LayerOnSlopeTool/trunk/xsd/DamMStabDefinitions.xsd	(.../DamMStabDefinitions.xsd)	(revision 3141)
@@ -34,13 +34,13 @@
             <xs:sequence minOccurs="1" maxOccurs="1">
               <xs:element minOccurs="2" maxOccurs="unbounded" name="tnsbPrefixPLPoint">
                 <xs:complexType>
-                  <xs:attribute name="XCoord" type="xs:double" use="optional" />
-                  <xs:attribute name="YCoord" type="xs:double" use="optional" />
+                  <xs:attribute name="XCoord" type="xs:double" use="required" />
+                  <xs:attribute name="YCoord" type="xs:double" use="required" />
                 </xs:complexType>
               </xs:element>
             </xs:sequence>
-            <xs:attribute name="IsPhreatic" type="xs:boolean" use="optional" />
-            <xs:attribute name="BoundaryLayer" type="xs:integer" use="required" />
+            <xs:attribute name="IsPhreatic" type="xs:boolean" use="required" />
+            <xs:attribute name="BoundaryLayer" type="xs:int" use="required" />
           </xs:complexType>
         </xs:element>
       </xs:sequence>
Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillXmlDamMStabDocFromIo.cs
===================================================================
diff -u -r3138 -r3141
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillXmlDamMStabDocFromIo.cs	(.../FillXmlDamMStabDocFromIo.cs)	(revision 3138)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillXmlDamMStabDocFromIo.cs	(.../FillXmlDamMStabDocFromIo.cs)	(revision 3141)
@@ -20,36 +20,61 @@
 // All rights reserved.
 
 using System.Collections.Generic;
+using System.Data;
 
 namespace Deltares.LayerOnSlopeTool.Io
 {
     /// <summary>Class for transferring Io data to Xml data</summary>
     public static class FillXmlDamMStabDocFromIo
     {
         /// <summary>Fills the XML dam m stab document.</summary>
-        /// <param name="ioDamMStabDamDoc">The io dam m stab dam document.</param>
+        /// <param name="ioMStabDamDoc">The io dam m stab dam document.</param>
         /// <returns></returns>
-        public static tnsPrefixDamMStabDoc FillXmlDamMStabDoc(IoMStabDamDoc ioDamMStabDamDoc)
+        public static tnsPrefixDamMStabDoc FillXmlDamMStabDoc(IoMStabDamDoc ioMStabDamDoc)
         {
             var xmlDamMStabDoc = new tnsPrefixDamMStabDoc();
             xmlDamMStabDoc.tnsPrefixDamMStabInput = new tnsPrefixDamMStabDocTnsPrefixDamMStabInput();
 
             xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixGeometryCreationOptions = new tnsbPrefixGeometryCreationOptions();
-            TransferGeometryCreationOptions(ioDamMStabDamDoc.MStabInput.GeometryCreationOptions, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixGeometryCreationOptions);
+            TransferGeometryCreationOptions(ioMStabDamDoc.MStabInput.GeometryCreationOptions, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixGeometryCreationOptions);
 
             xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixModel = new tnsbPrefixModel();
-            TransferModel(ioDamMStabDamDoc.MStabInput.Model, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixModel);
+            TransferModel(ioMStabDamDoc.MStabInput.Model, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixModel);
 
-            xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine = new tnsbPrefixSurfaceLineTnsbPrefixSurfacePoint[ioDamMStabDamDoc.MStabInput.SurfaceLine.Count];
-            TransferSurfaceline(ioDamMStabDamDoc.MStabInput.SurfaceLine, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine);
+            xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine = new tnsbPrefixSurfaceLineTnsbPrefixSurfacePoint[ioMStabDamDoc.MStabInput.SurfaceLine.Count];
+            TransferSurfaceline(ioMStabDamDoc.MStabInput.SurfaceLine, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine);
 
             xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixCharacteristicPoints = 
-                new tnsbPrefixCharacteristicPointsTnsbPrefixCharacteristicPoint[ioDamMStabDamDoc.MStabInput.CharacteristicPoints.Count];
-            TransferCharacteristicPoints(ioDamMStabDamDoc.MStabInput.CharacteristicPoints, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixCharacteristicPoints);
+                new tnsbPrefixCharacteristicPointsTnsbPrefixCharacteristicPoint[ioMStabDamDoc.MStabInput.CharacteristicPoints.Count];
+            TransferCharacteristicPoints(ioMStabDamDoc.MStabInput.CharacteristicPoints, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixCharacteristicPoints);
 
+            xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixExternalPLLines =
+                new tnsbPrefixExternalPLLinesTnsbPrefixPLLine[ioMStabDamDoc.MStabInput.ExternalPlLines.Count];
+            TransferPlLines(ioMStabDamDoc.MStabInput.ExternalPlLines, xmlDamMStabDoc.tnsPrefixDamMStabInput.tnsbPrefixExternalPLLines);
+
             return xmlDamMStabDoc;
         }
 
+        private static void TransferPlLines(List<IoPlLine> ioPlLines, tnsbPrefixExternalPLLinesTnsbPrefixPLLine[] xmlPlLines)
+        {
+            for (int plLineIndex = 0; plLineIndex < ioPlLines.Count; plLineIndex++)
+            {
+                xmlPlLines[plLineIndex] = new tnsbPrefixExternalPLLinesTnsbPrefixPLLine();
+                var ioPlLine = ioPlLines[plLineIndex];
+                xmlPlLines[plLineIndex].BoundaryLayer = ioPlLine.BoundaryLayer;
+                xmlPlLines[plLineIndex].IsPhreatic = ioPlLine.IsPhreatic;
+                xmlPlLines[plLineIndex].tnsbPrefixPLPoint = new tnsbPrefixExternalPLLinesTnsbPrefixPLLineTnsbPrefixPLPoint[ioPlLine.Points.Count];
+                for (int pointIndex = 0; pointIndex < ioPlLine.Points.Count; pointIndex++)
+                {
+                    xmlPlLines[plLineIndex].tnsbPrefixPLPoint[pointIndex] = new tnsbPrefixExternalPLLinesTnsbPrefixPLLineTnsbPrefixPLPoint()
+                    {
+                        XCoord = ioPlLine.Points[pointIndex].X,
+                        YCoord = ioPlLine.Points[pointIndex].Y
+                    };
+                }
+            }
+        }
+
         private static void TransferCharacteristicPoints(List<IoCharacteristicPoint> ioCharacteristicPoints, 
             tnsbPrefixCharacteristicPointsTnsbPrefixCharacteristicPoint[] xmlCharacteristicPoints)
         {
Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillIoDamMStabDocFromXml.cs
===================================================================
diff -u -r3138 -r3141
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillIoDamMStabDocFromXml.cs	(.../FillIoDamMStabDocFromXml.cs)	(revision 3138)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/FillIoDamMStabDocFromXml.cs	(.../FillIoDamMStabDocFromXml.cs)	(revision 3141)
@@ -27,18 +27,43 @@
     public static class FillIoDamMStabDocFromXml
     {
         /// <summary>Fills the io dam m stab document.</summary>
-        /// <param name="xmlDamMStabDamDoc">The XML dam m stab dam document.</param>
+        /// <param name="xmlMStabDamDoc">The XML dam m stab dam document.</param>
         /// <returns></returns>
-        public static IoMStabDamDoc FillIoDamMStabDoc(tnsPrefixDamMStabDoc xmlDamMStabDamDoc)
+        public static IoMStabDamDoc FillIoDamMStabDoc(tnsPrefixDamMStabDoc xmlMStabDamDoc)
         {
             var ioMStabDamDoc = new IoMStabDamDoc();
-            TransferGeometryCreationOptions(xmlDamMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixGeometryCreationOptions, ioMStabDamDoc.MStabInput.GeometryCreationOptions);
-            TransferModel(xmlDamMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixModel, ioMStabDamDoc.MStabInput.Model);
-            TransferSurfaceLine(xmlDamMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine, ioMStabDamDoc.MStabInput.SurfaceLine);
-            TransferCharacteristicPoints(xmlDamMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixCharacteristicPoints, ioMStabDamDoc.MStabInput.CharacteristicPoints);
+            TransferGeometryCreationOptions(xmlMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixGeometryCreationOptions, ioMStabDamDoc.MStabInput.GeometryCreationOptions);
+            TransferModel(xmlMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixModel, ioMStabDamDoc.MStabInput.Model);
+            TransferSurfaceLine(xmlMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixSurfaceLine, ioMStabDamDoc.MStabInput.SurfaceLine);
+            TransferCharacteristicPoints(xmlMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixCharacteristicPoints, ioMStabDamDoc.MStabInput.CharacteristicPoints);
+            TransferPlLines(xmlMStabDamDoc.tnsPrefixDamMStabInput.tnsbPrefixExternalPLLines, ioMStabDamDoc.MStabInput.ExternalPlLines);
             return ioMStabDamDoc;
         }
 
+        private static void TransferPlLines(tnsbPrefixExternalPLLinesTnsbPrefixPLLine[] xmlPlLines, List<IoPlLine> ioPlLines)
+        {
+            for (int plLineIndex = 0; plLineIndex < xmlPlLines.Length; plLineIndex++)
+            {
+                var xmlPlLine = xmlPlLines[plLineIndex];
+                ioPlLines.Add(new IoPlLine()
+                {
+                    IsPhreatic = xmlPlLine.IsPhreatic,
+                    BoundaryLayer = xmlPlLine.BoundaryLayer
+                });
+                if (xmlPlLine.tnsbPrefixPLPoint != null)
+                {
+                    for (int pointIndex = 0; pointIndex < xmlPlLine.tnsbPrefixPLPoint.Length; pointIndex++)
+                    {
+                        ioPlLines[plLineIndex].Points.Add(new IoGeometryPoint()
+                        {
+                            X = xmlPlLine.tnsbPrefixPLPoint[pointIndex].XCoord,
+                            Y = xmlPlLine.tnsbPrefixPLPoint[pointIndex].YCoord
+                        });
+                    }
+                }
+            }
+        }
+
         private static void TransferCharacteristicPoints(tnsbPrefixCharacteristicPointsTnsbPrefixCharacteristicPoint[] xmlCharacteristicPoints, 
             List<IoCharacteristicPoint> ioCharacteristicPoints)
         {
Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/DamMStabDoc.cs
===================================================================
diff -u -r3136 -r3141
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/DamMStabDoc.cs	(.../DamMStabDoc.cs)	(revision 3136)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/DamMStabDoc.cs	(.../DamMStabDoc.cs)	(revision 3141)
@@ -206,10 +206,8 @@
         
         private bool isPhreaticField;
         
-        private bool isPhreaticFieldSpecified;
+        private int boundaryLayerField;
         
-        private string boundaryLayerField;
-        
         /// <remarks/>
         [System.Xml.Serialization.XmlElementAttribute("tnsbPrefixPLPoint")]
         public tnsbPrefixExternalPLLinesTnsbPrefixPLLineTnsbPrefixPLPoint[] tnsbPrefixPLPoint {
@@ -233,20 +231,9 @@
         }
         
         /// <remarks/>
-        [System.Xml.Serialization.XmlIgnoreAttribute()]
-        public bool IsPhreaticSpecified {
+        [System.Xml.Serialization.XmlAttributeAttribute()]
+        public int BoundaryLayer {
             get {
-                return this.isPhreaticFieldSpecified;
-            }
-            set {
-                this.isPhreaticFieldSpecified = value;
-            }
-        }
-        
-        /// <remarks/>
-        [System.Xml.Serialization.XmlAttributeAttribute(DataType="integer")]
-        public string BoundaryLayer {
-            get {
                 return this.boundaryLayerField;
             }
             set {
@@ -265,12 +252,8 @@
         
         private double xCoordField;
         
-        private bool xCoordFieldSpecified;
-        
         private double yCoordField;
         
-        private bool yCoordFieldSpecified;
-        
         /// <remarks/>
         [System.Xml.Serialization.XmlAttributeAttribute()]
         public double XCoord {
@@ -283,17 +266,6 @@
         }
         
         /// <remarks/>
-        [System.Xml.Serialization.XmlIgnoreAttribute()]
-        public bool XCoordSpecified {
-            get {
-                return this.xCoordFieldSpecified;
-            }
-            set {
-                this.xCoordFieldSpecified = value;
-            }
-        }
-        
-        /// <remarks/>
         [System.Xml.Serialization.XmlAttributeAttribute()]
         public double YCoord {
             get {
@@ -303,17 +275,6 @@
                 this.yCoordField = value;
             }
         }
-        
-        /// <remarks/>
-        [System.Xml.Serialization.XmlIgnoreAttribute()]
-        public bool YCoordSpecified {
-            get {
-                return this.yCoordFieldSpecified;
-            }
-            set {
-                this.yCoordFieldSpecified = value;
-            }
-        }
     }
     
     /// <remarks/>
Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/IoPlLine.cs
===================================================================
diff -u -r3117 -r3141
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/IoPlLine.cs	(.../IoPlLine.cs)	(revision 3117)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Io/IoPlLine.cs	(.../IoPlLine.cs)	(revision 3141)
@@ -19,10 +19,25 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System.Collections.Generic;
+
 namespace Deltares.LayerOnSlopeTool.Io
 {
+    /// <summary>PL-line type</summary>
     public class IoPlLine
     {
-        
+        /// <summary>Gets or sets a value indicating whether this instance is the phreatic line.</summary>
+        /// <value>
+        ///   <c>true</c> if this instance is the phreatic line; otherwise, <c>false</c>.</value>
+        public bool IsPhreatic { get; set; }
+
+        /// <summary>Gets or sets the index of the boundary layer.</summary>
+        /// <value>The index of the boundary layer.</value>
+        public int BoundaryLayer { get; set; }
+
+        /// <summary>Gets the points.</summary>
+        /// <value>The points.</value>
+        public List<IoGeometryPoint> Points { get; } = new List<IoGeometryPoint>();
+
     }
 }
\ No newline at end of file