Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.Designer.cs
===================================================================
diff -u
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.Designer.cs	(revision 0)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.Designer.cs	(revision 362)
@@ -0,0 +1,90 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Deltares.DamPiping.Sellmeijer4ForcesCalculator.Properties {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Resources {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Resources() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Deltares.DamPiping.Sellmeijer4ForcesCalculator.Properties.Resources", typeof(Resources).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Parameter {0} is not a number (NaN)..
+        /// </summary>
+        internal static string PipingCalculatorSellmeijer4Forces_LogParameterIsNaN_NaNParameterError {
+            get {
+                return ResourceManager.GetString("PipingCalculatorSellmeijer4Forces_LogParameterIsNaN_NaNParameterError", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to HRiver - HExit - (Rc*DTotal) may not be 0..
+        /// </summary>
+        internal static string PipingCalculatorSellmeijer4Forces_PerformValidate_HRiver_HExit_Rc_DTotal_Zero {
+            get {
+                return ResourceManager.GetString("PipingCalculatorSellmeijer4Forces_PerformValidate_HRiver_HExit_Rc_DTotal_Zero", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Rc may not be less than 0..
+        /// </summary>
+        internal static string PipingCalculatorSellmeijer4Forces_PerformValidate_RcLessThan0 {
+            get {
+                return ResourceManager.GetString("PipingCalculatorSellmeijer4Forces_PerformValidate_RcLessThan0", resourceCulture);
+            }
+        }
+    }
+}
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.resx
===================================================================
diff -u
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.resx	(revision 0)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.resx	(revision 362)
@@ -0,0 +1,129 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="PipingCalculatorSellmeijer4Forces_PerformValidate_HRiver_HExit_Rc_DTotal_Zero" xml:space="preserve">
+    <value>HRiver - HExit - (Rc*DTotal) may not be 0.</value>
+  </data>
+  <data name="PipingCalculatorSellmeijer4Forces_PerformValidate_RcLessThan0" xml:space="preserve">
+    <value>Rc may not be less than 0.</value>
+  </data>
+  <data name="PipingCalculatorSellmeijer4Forces_LogParameterIsNaN_NaNParameterError" xml:space="preserve">
+    <value>Parameter {0} is not a number (NaN).</value>
+  </data>
+</root>
\ No newline at end of file
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.nl-NL.resx
===================================================================
diff -u
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.nl-NL.resx	(revision 0)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/Resources.nl-NL.resx	(revision 362)
@@ -0,0 +1,129 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="PipingCalculatorSellmeijer4Forces_LogParameterIsNaN_NaNParameterError" xml:space="preserve">
+    <value>Parameter {0} heeft geen waarde (NaN).</value>
+  </data>
+  <data name="PipingCalculatorSellmeijer4Forces_PerformValidate_HRiver_HExit_Rc_DTotal_Zero" xml:space="preserve">
+    <value>De term HRiver - HExit - (Rc*DTotal) mag niet nul zijn.</value>
+  </data>
+  <data name="PipingCalculatorSellmeijer4Forces_PerformValidate_RcLessThan0" xml:space="preserve">
+    <value>De waarde voor de dempingsfactor mag niet lager dan 0 zijn.</value>
+  </data>
+</root>
\ No newline at end of file
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj
===================================================================
diff -u -r351 -r362
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj	(.../Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj)	(revision 351)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj	(.../Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj)	(revision 362)
@@ -37,12 +37,26 @@
     <Compile Include="..\GlobalAssemblyInfo.cs">
       <Link>Properties\GlobalAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="Geo\Physics.cs" />
     <Compile Include="PipingCalculatorSellmeijer4Forces.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Properties\Resources.Designer.cs">
+      <AutoGen>True</AutoGen>
+      <DesignTime>True</DesignTime>
+      <DependentUpon>Resources.resx</DependentUpon>
+    </Compile>
   </ItemGroup>
   <ItemGroup>
     <None Include="Properties\AssemblyInfo.cs.svn" />
   </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="Properties\Resources.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>Resources.Designer.cs</LastGenOutput>
+      <SubType>Designer</SubType>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Properties\Resources.nl-NL.resx" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
     <PreBuildEvent>"$(ProjectDir)..\..\utils\svn_insert_version.cmd" "$(ProjectDir)Properties"</PreBuildEvent>
Index: dam failuremechanisms/damPiping/trunk/doc/Evaluation Piping/Nieuwe rekenregel bligh Sellmeijeruli.xls
===================================================================
diff -u
Binary files differ
Index: dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests.csproj
===================================================================
diff -u -r351 -r362
--- dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests.csproj	(.../Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests.csproj)	(revision 351)
+++ dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests.csproj	(.../Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests.csproj)	(revision 362)
@@ -40,6 +40,12 @@
     <Compile Include="PipingCalculatorSellmeijer4ForcesTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\Deltares.DamPiping.Sellmeijer4ForcesCalculator\Deltares.DamPiping.Sellmeijer4ForcesCalculator.csproj">
+      <Project>{E5BBEEF4-FA0F-4EB7-871B-A46FFE515798}</Project>
+      <Name>Deltares.DamPiping.Sellmeijer4ForcesCalculator</Name>
+    </ProjectReference>
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/AssemblyInfo.cs.svn
===================================================================
diff -u -r336 -r362
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/AssemblyInfo.cs.svn	(.../AssemblyInfo.cs.svn)	(revision 336)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Properties/AssemblyInfo.cs.svn	(.../AssemblyInfo.cs.svn)	(revision 362)
@@ -7,3 +7,4 @@
 
 [assembly: AssemblyVersion("17.1.0.SVNREV")]
 [assembly: AssemblyFileVersion("17.1.0.SVNREV")]
+[assembly: InternalsVisibleTo("Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests")]
Index: dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/PipingCalculatorSellmeijer4ForcesTest.cs
===================================================================
diff -u -r351 -r362
--- dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/PipingCalculatorSellmeijer4ForcesTest.cs	(.../PipingCalculatorSellmeijer4ForcesTest.cs)	(revision 351)
+++ dam failuremechanisms/damPiping/trunk/src/Tests/Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests/PipingCalculatorSellmeijer4ForcesTest.cs	(.../PipingCalculatorSellmeijer4ForcesTest.cs)	(revision 362)
@@ -1,5 +1,8 @@
 //using Deltares.Geotechnics.TestUtils;
 //using Deltares.Standard;
+
+using Deltares.DamPiping.Sellmeijer4ForcesCalculator;
+using Deltares.DamPiping.Sellmeijer4ForcesCalculator.Geo;
 using NUnit.Framework;
 
 namespace Deltares.DamPiping.Sellmeijer4ForcesCalculatorTests
@@ -8,96 +11,227 @@
     [TestFixture]
     public class PipingCalculatorSellmeijer4ForcesTest
     {
-//        [Test]
-//        public void CanCalculateThePipingFactorUsingSellmeijer4ForcesNoUplift()
-//        {
-//            using (var surfaceLine = FactoryForSurfaceLineTests.CreateSurfaceLineTutorial1())
-//            using(var dike = new Dike())
-//            using (var location = new Location())
-//            {
-//                var soilProfile = FactoryForSoilProfileTests.CreatePipingSellmeijerProfileWithOneSandlayer();
-//                soilProfile.Layers[0].Soil.AbovePhreaticLevel = 20.0;
-//                soilProfile.Layers[0].Soil.BelowPhreaticLevel = 22.0;
-//                var modelParametersForPLLines = new ModelParametersForPLLines();//are the values initialized correctly?
-//
-//                var calculator = new PipingCalculatorSellmeijer4Forces(modelParametersForPLLines, 1.0, dike.GaugePLLines, dike.Gauges, 1.0);
-//                location.HeadPl3 = -1.0;
-//                location.PolderLevel = -1.0;
-//
-//                var actual = calculator.CalculatePipingFactor(location, surfaceLine, soilProfile, 1.0);
-//
-//                // Calculation at toe of dike
-//                // Phreatic level in profile = 0
-//                // PL3 = waterlevel = -1 m
-//                // Mass of soil volume above 
-//                //   wet 1 m x 22 kN/m3 = 22
-//                //   wet 1 m x 20 kN/m3 = 20
-//                //   Total: 22 + 20 = 42
-//                // Phreatic pressure
-//                //   1 m x 9.81 kN/m3 = 9.81
-//                // UpliftFactor = 42/9.81 = 4.281
-//                // UpliftFactor > 1.0, so no piping, so returns cDefaultMaxReturnValue
-//
-//                var expected = PipingCalculatorSellmeijer4Forces.cDefaultMaxReturnValue;
-//                Assert.AreEqual(expected, actual);
-//            }
-//        }
-//
-//        /// <summary>
-//        /// These results are documented in the document
-//        /// ".\documents\DAM\Evaluation Piping\Nieuwe rekenregel bligh Sellmeijeruli.xls"
-//        /// </summary>
-//        [Test]
-//        public void CanCalculateThePipingFactorUsingSellmeijer4Forces()
-//        {
-//            using (var surfaceLine = FactoryForSurfaceLineTests.CreateSurfaceLineTutorial1())
-//            using(var dike = new Dike())
-//            using (var location = new Location())
-//            {
-//                var soilProfile = FactoryForSoilProfileTests.CreatePipingSellmeijerProfileWithOneSandlayer();
-//                var modelParametersForPLLines = new ModelParametersForPLLines();
-//                modelParametersForPLLines.DampingFactorPL4 = 0.0;
-//
-//                var calculator = new PipingCalculatorSellmeijer4Forces(modelParametersForPLLines,
-//                    1.0, dike.GaugePLLines, dike.Gauges, 1.0);
-//
-//                var actual = calculator.CalculatePipingFactor(location, surfaceLine, soilProfile, 1.0);
-//
-//                // Phreatic level in profile
-//                // Mass of soil volume above 
-//                //   material above bottom sandlayer: 0 to -5 m
-//                //   dry/wet 5 m x 1 kN/m3 = 5
-//                // Phreatic pressure (Head PLLine 4 is ca. 1.0
-//                //   6.0 m x 10 kN/m3 = 60,0
-//                // UpliftFactor = 5/60.0 = 0.0833
-//                // UpliftFactor < 1.0, so piping will occur in toe of dike
-//                //
-//
-//                const double cTolerance = 0.000001;
-//                const double expected = 11.899117458988471; // Value is taken from the actual calculation itself and not manual calculated
-//                Assert.IsNotNull(actual);
-//                Assert.AreEqual(expected, actual.Value, cTolerance);
-//            }
-//        }
-//        [Test]
-//
-//        public void CanCalculateHCritical()
-//        {
-//            const double cTolerance = 0.000001;
-//            const double cwhitesConstant = 0.25;
-//            const double cbeddingAngle = 41.0;
-//
-//            double hCritical = PipingCalculatorSellmeijer4Forces.CalculateHCritical(cwhitesConstant, cbeddingAngle, 180, 15.00, 7.00e-05, 3, Physics.WaterViscosity);
-//            Assert.AreEqual(2.757966400, hCritical, cTolerance);
-//            hCritical = PipingCalculatorSellmeijer4Forces.CalculateHCritical(cwhitesConstant, cbeddingAngle, 260, 15.00, 1.30e-04, 3, Physics.WaterViscosity);
-//            Assert.AreEqual(3.184432652, hCritical, cTolerance);
-//            hCritical = PipingCalculatorSellmeijer4Forces.CalculateHCritical(cwhitesConstant, cbeddingAngle, 180, 20.00, 7.00e-05, 3, Physics.WaterViscosity);
-//            Assert.AreEqual(3.650076587, hCritical, cTolerance);
-//            hCritical = PipingCalculatorSellmeijer4Forces.CalculateHCritical(cwhitesConstant, cbeddingAngle, 260, 20.00, 1.30e-04, 3, Physics.WaterViscosity);
-//            Assert.AreEqual(4.215258070, hCritical, cTolerance);
-//            hCritical = PipingCalculatorSellmeijer4Forces.CalculateHCritical(cwhitesConstant, cbeddingAngle, 180, 60.00, 7.00e-05, 3, Physics.WaterViscosity);
-//            Assert.AreEqual(10.705479854, hCritical, cTolerance);
-//        }        
+        const double CTolerance = 0.000001;
+
+        [Test]
+        public void TestCalculationDefault()
+        {
+            var bc = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1
+            };
+            bc.Calculate();
+            Assert.AreEqual(0, bc.FoSp);
+            Assert.AreEqual(double.NaN, bc.Hc);
+        }
+
+        [Test]
+        public void TestCalculation()
+        {
+            // reducedFall = HRiver - HExit - (Rc * DTotal) = 1.0 - 0.0 - (0.3 * 2.0) = 0.4
+            // FoSp = Hc / reducedFall = 4.7596 / 0.4 = 11.899
+            // For calculation of Hc see TestCanCalculateHCritical
+            // See also "..\..\doc\Evaluation Piping\Nieuwe rekenregel bligh Sellmeijeruli.xls"
+            const double diff = 0.0001;
+            var bc = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1.0,
+                HExit = 0.0,
+                Rc = 0.3,
+                DTotal = 2.0,
+                AquiferHeight = 8.0,
+                SeepageLength = 40.5,
+                D70 = 200.0,
+                WhitesConstant = 0.25,
+                BeddingAngle = 37.0,
+                WaterViscosity = 1.33E-06,
+                PermeabilityKx = 0.0001
+            };
+            bc.Calculate();
+            Assert.AreEqual(11.899117458988471, bc.FoSp, diff);
+            Assert.AreEqual(4.7596469835953883, bc.Hc, diff);
+        }
+
+
+        [Test]
+        public void TestCanCalculateHCritical()
+        {
+            const double cwhitesConstant = 0.25;
+            const double cbeddingAngle = 41.0;
+            var pc = new PipingCalculatorSellmeijer4Forces
+            {
+                WhitesConstant = cwhitesConstant,
+                BeddingAngle = cbeddingAngle,
+                AquiferHeight = 3.0,
+                WaterViscosity = 1.33E-06
+            };
+
+            pc.D70 = 180.0;
+            pc.SeepageLength = 15.00;
+            pc.PermeabilityKx = 7.00e-05;
+            var hCritical = pc.CalculateHCritical();
+            Assert.AreEqual(2.757966400, hCritical, CTolerance);
+
+            pc.D70 = 260.0;
+            pc.SeepageLength = 15.00;
+            pc.PermeabilityKx = 1.30e-04;
+            hCritical = pc.CalculateHCritical();
+            Assert.AreEqual(3.184432652, hCritical, CTolerance);
+
+            pc.D70 = 180.0;
+            pc.SeepageLength = 20.00;
+            pc.PermeabilityKx = 7.00e-05;
+            hCritical = pc.CalculateHCritical();
+            Assert.AreEqual(3.650076587, hCritical, CTolerance);
+
+            pc.D70 = 260.0;
+            pc.SeepageLength = 20.00;
+            pc.PermeabilityKx = 1.30e-04;
+            hCritical = pc.CalculateHCritical();
+            Assert.AreEqual(4.215258070, hCritical, CTolerance);
+
+            pc.D70 = 180.0;
+            pc.SeepageLength = 60.00;
+            pc.PermeabilityKx = 7.00e-05;
+            hCritical = pc.CalculateHCritical();
+            Assert.AreEqual(10.705479854, hCritical, CTolerance);
+        }
+
+        [Test]
+        public void TestTermAlpha()
+        {
+            var term = PipingCalculatorSellmeijer4Forces.TermAlpha(15.00, 3.0);
+            Assert.AreEqual(1.5772333244309182, term, CTolerance);
+        }
+
+        [Test]
+        public void TestKIntrinisc()
+        {
+            var term = PipingCalculatorSellmeijer4Forces.KIntrinisc(7.00e-05, 1.33E-06);
+            Assert.AreEqual(9.4903160040774713E-12, term, CTolerance);
+        }
+
+        [Test]
+        public void TestTermC()
+        {
+            var term = PipingCalculatorSellmeijer4Forces.TermC(0.25, 41.0, 180.0, 15.00, 7.00e-05, 1.33E-06);
+            Assert.AreEqual(0.0861830519728676, term, CTolerance);
+        }
+
+        [Test]
+        public void TestTermLnC()
+        {
+            var term = PipingCalculatorSellmeijer4Forces.TermLnC(0.25, 41.0, 180.0, 15.00, 7.00e-05, 1.33E-06);
+            Assert.AreEqual(0.92512817334870923, term, CTolerance);
+        }
+
+        [Test]
+        public void TestValidateNaNParameter()
+        {
+            var bc = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1.0,
+                HExit = 0.0,
+                Rc = 0.3,
+                DTotal = 2.0,
+                AquiferHeight = 8.0,
+                SeepageLength = 40.5,
+                D70 = 200.0,
+                WhitesConstant = 0.25,
+                BeddingAngle = 37.0,
+                WaterViscosity = 1.33E-06,
+                PermeabilityKx = 0.0001
+            };
+            var originalErrors = bc.Validate();
+
+            bc.HRiver = double.NaN;
+            bc.HExit = double.NaN;
+            bc.Rc = double.NaN;
+            bc.DTotal = double.NaN;
+            bc.AquiferHeight = double.NaN;
+            bc.SeepageLength = double.NaN;
+            bc.D70 = double.NaN;
+            bc.WhitesConstant = double.NaN;
+            bc.BeddingAngle = double.NaN;
+            bc.WaterViscosity = double.NaN;
+            bc.PermeabilityKx = double.NaN;
+            var nanErrors = bc.Validate();
+            Assert.AreEqual(originalErrors.Count + 11, nanErrors.Count);
+        }
+
+        [Test]
+        [SetUICulture("en-US")]
+        public void TestValidateRcLessThan0En()
+        {
+            var calculator = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1.0,
+                HExit = 0.0,
+                Rc = -1e-6,
+                DTotal = 2.0,
+                AquiferHeight = 8.0,
+                SeepageLength = 40.5,
+                D70 = 200.0,
+                WhitesConstant = 0.25,
+                BeddingAngle = 37.0,
+                WaterViscosity = 1.33E-06,
+                PermeabilityKx = 0.0001
+            };
+            var errors = calculator.Validate();
+            Assert.AreEqual(1, errors.Count);
+            var expectedMessageEN = "Rc may not be less than 0.";
+            CollectionAssert.AreEqual(new[] { expectedMessageEN }, errors);
+        }
+
+        [Test]
+        [SetUICulture("nl-NL")]
+        public void TestValidateRcLessThan0Nl()
+        {
+            var calculator = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1.0,
+                HExit = 0.0,
+                Rc = -1e-6,
+                DTotal = 2.0,
+                AquiferHeight = 8.0,
+                SeepageLength = 40.5,
+                D70 = 200.0,
+                WhitesConstant = 0.25,
+                BeddingAngle = 37.0,
+                WaterViscosity = 1.33E-06,
+                PermeabilityKx = 0.0001
+            };
+            var errors = calculator.Validate();
+            Assert.AreEqual(1, errors.Count);
+            var expectedMessageNL = "De waarde voor de dempingsfactor mag niet lager dan 0 zijn.";
+            CollectionAssert.AreEqual(new[] { expectedMessageNL }, errors);
+        }
+        
+        [Test]
+        [SetUICulture("nl-NL")]
+        public void TestValidateReducedFall()
+        {
+            var calculator = new PipingCalculatorSellmeijer4Forces
+            {
+                HRiver = 1.0,
+                HExit = 1.0,
+                Rc = 0,
+                DTotal = 2.0,
+                AquiferHeight = 8.0,
+                SeepageLength = 40.5,
+                D70 = 200.0,
+                WhitesConstant = 0.25,
+                BeddingAngle = 37.0,
+                WaterViscosity = 1.33E-06,
+                PermeabilityKx = 0.0001
+            };
+            var errors = calculator.Validate();
+            Assert.AreEqual(1, errors.Count);
+            var expectedMessageEN = "De term HRiver - HExit - (Rc*DTotal) mag niet nul zijn.";
+            CollectionAssert.AreEqual(new[] { expectedMessageEN }, errors);
+        }
+        
+
     }
 }
 
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Geo/Physics.cs
===================================================================
diff -u
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Geo/Physics.cs	(revision 0)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/Geo/Physics.cs	(revision 362)
@@ -0,0 +1,27 @@
+namespace Deltares.DamPiping.Sellmeijer4ForcesCalculator.Geo
+{
+    /// <summary>
+    /// Physics class with constants that can be redefined
+    /// </summary>
+    public class Physics
+    {
+        /// <summary>
+        /// The gravity constant in  m/s2
+        /// </summary>
+        public const double GravityConstant = 9.81;
+
+        /// <summary>
+        /// The water density in kg/m3 For temperature = 4 degree Celcius
+        /// </summary>
+        /// 
+        public const double WaterDensity = 1000;
+
+        /// <summary>
+        /// Gets the unit weight of water in kN/m3.
+        /// </summary>
+        /// <value>
+        /// The unit weight of water.
+        /// </value>
+        public const double UnitWeightOfwater = GravityConstant*WaterDensity*0.001;
+    }
+}
\ No newline at end of file
Index: dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/PipingCalculatorSellmeijer4Forces.cs
===================================================================
diff -u -r351 -r362
--- dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/PipingCalculatorSellmeijer4Forces.cs	(.../PipingCalculatorSellmeijer4Forces.cs)	(revision 351)
+++ dam failuremechanisms/damPiping/trunk/src/Deltares.DamPiping.Sellmeijer4ForcesCalculator/PipingCalculatorSellmeijer4Forces.cs	(.../PipingCalculatorSellmeijer4Forces.cs)	(revision 362)
@@ -7,132 +7,246 @@
 using System;
 using System.Collections.Generic;
 using System.Runtime.Serialization;
+using Deltares.DamPiping.Sellmeijer4ForcesCalculator.Geo;
+using Deltares.DamPiping.Sellmeijer4ForcesCalculator.Properties;
 
 namespace Deltares.DamPiping.Sellmeijer4ForcesCalculator
 {
 
     public class PipingCalculatorSellmeijer4Forces
     {
 
+        public const double RcDefault = 0.3;
+        public const double Epsilon = 1e-8;
+        protected const double DegreeToRadian = Math.PI / 180.0;
+        protected static double GammaPDividedByGammaW = 16.5 / Physics.UnitWeightOfwater; // Gamma korrel is now assumed 16.5 kN/m3
 
+        private double foSp;
+        private double hc;
+        private double rc = RcDefault;
+        private double reducedFall;
+
         /// <summary>
+        /// River level as input
+        /// </summary>
+        public double HRiver { get; set; }
+
+        /// <summary>
+        /// Phreatic level at exit point as input
+        /// </summary>
+        public double HExit { get; set; }
+
+        /// <summary>
+        /// Reduction factor as input
+        /// </summary>
+        public double Rc
+        {
+            get { return rc; }
+            set { rc = value; }
+        }
+
+        /// <summary>
+        /// Total thickness of cover layer as input
+        /// </summary>
+        public double DTotal { get; set; }
+
+        /// <summary>
+        /// Height of the aquifer as input
+        /// </summary>
+        public double AquiferHeight { get; set; }
+
+        /// <summary>
+        /// Seepage length (xExit - xEntry) as input
+        /// </summary>
+        public double SeepageLength { get; set; }
+
+        /// <summary>
+        /// Median grainsize D70 as input
+        /// </summary>
+        public double D70 { get; set; }
+
+        /// <summary>
+        /// The whites constant as input
+        /// </summary>
+        public double WhitesConstant { get; set; }
+
+        /// <summary>
+        /// The bedding angle as input
+        /// </summary>
+        public double BeddingAngle { get; set; }
+
+        /// <summary>
+        /// The permeability kx as input
+        /// </summary>
+        public double PermeabilityKx { get; set; }
+
+        /// <summary>
+        /// The water viscosity as input
+        /// </summary>
+        public double WaterViscosity { get; set; }
+
+        /// <summary>
+        /// Safety factor of piping as result
+        /// </summary>
+        public double FoSp
+        {
+            get { return foSp; }
+        }
+
+        /// <summary>
+        /// Critical head difference for piping as result.
+        /// </summary>
+        public double Hc
+        {
+            get
+            {
+                return hc;
+            }
+        }
+
+        /// <summary>
         /// Start the calculation of all output parameters.
         /// </summary>
-//        public void Calculate()
-//        {
-//            hc = GetHc();
-//            reducedFall = GetReducedFall();
-////            zp = (ModelFactorPiping * hc) - reducedFall;
-//            DetermineFactorOfSafety();
-////            hcp = (ModelFactorPiping * hc) + HExit + (Rc * DTotal);
-//        }
+        public void Calculate()
+        {
+            hc = CalculateHCritical();
+            reducedFall = GetReducedFall();
+            DetermineFactorOfSafety();
+        }
 
-        private const double cBligh = 18.0;
+        private void DetermineFactorOfSafety()
+        {
+            const double cDefaultMaxReturnValue = 90.0;
+            const double cDefaultMinReturnValue = 0.0;
 
-//        private double CalculatePipingFactorAtLevel(Location location, double waterLevel, double surfaceLevel)
-//        {
-//            PipingCalculatorInput pipingCalculatorInput = DefinePipingInputFromModel();
-//
-//            var dCoverLayer = DetermineHeightCoverLayer(surfaceLevel);
-//            var soilProfile1DAquiferLayerCombiner = new SoilProfile1DAquiferLayerCombiner(SoilProfile);
-//            AquiferLayerWithParameters aquiferLayerWithParameters = soilProfile1DAquiferLayerCombiner.CombineLayers(UpliftLocationAndResult.LayerWhereUpliftOccuresId);
-//
-//            this.HCritical = CalculateHCritical(
-//                pipingCalculatorInput.WhitesConstant,
-//                pipingCalculatorInput.BeddingAngle,
-//                Physics.FactorMeterToMicroMeter * aquiferLayerWithParameters.D70,
-//                pipingCalculatorInput.Length,
-//                aquiferLayerWithParameters.PermeabilityKx,
-//                aquiferLayerWithParameters.Height,
-//                pipingCalculatorInput.WaterViscosity);
-//
-//            // Reference level is highest value of surfaceLevel or PolderLevel
-//            // Uit TR Zandmeevoerende wellen (1999): "Het verval dH is gelijk aan het verschil tussen buitenwaterstand (het ontwerppeil(OP)) 
-//            // bij zeedijken en de maatgevende hoogwaterstand (MHW bij rivierdijken) en de waterstand binnendijks ter plaatse van het uittredepunt, 
-//            // rekening houdend met zeespiegelrijzing etc.(zie paragraaf 3.7.2). In dien ter plaatse van het uittreepunt of de opbarstlocatie 
-//            // geen vrije waterstand heerst kan gerekend worden met het maaiveldniveau, rekening houdend met eventuele maaiveld daling (zie paragraaf 3.7.2)."
-//            double referenceLevel = Math.Max(location.PolderLevel, surfaceLevel);
-//
-//            // After consulting Erik Vastenburg, Jan Blinde, Andre Koelewijn, Alexander van Duinen en Huub de Bruijn
-//            // it was decided that the fluidisation correction shopuld be applied on the hActual and not the hCritical.
-//            double hActual = waterLevel - referenceLevel - (CDefaultFluidisationGradient * dCoverLayer);
-//            double pipingFactor = DeterminePipingFactorWithUpperLimit(hActual, HCritical);
-//            return pipingFactor;
-//        }
+            foSp = cDefaultMinReturnValue;
+            if (Math.Abs(hc) > Epsilon)
+            {
+                if (reducedFall <= 0)
+                {
+                    foSp = cDefaultMaxReturnValue;
+                }
+                foSp = hc / reducedFall;
+            }
+        }
 
+        /// <summary>
+        /// Calculate Hc according to the required model
+        /// </summary>
+        /// <returns>the proper value of Hc according to Sellmeijer 4 Forces</returns>
+        internal double CalculateHCritical()
+        {
+            double hcDividedByLNew = TermAlpha(SeepageLength, AquiferHeight) * TermC(WhitesConstant, BeddingAngle, D70, SeepageLength, PermeabilityKx, WaterViscosity) *
+                GammaPDividedByGammaW * Math.Tan(DegreeToRadian * BeddingAngle) *
+                TermLnC(WhitesConstant, BeddingAngle, D70, SeepageLength, PermeabilityKx, WaterViscosity);
+            double result = hcDividedByLNew*SeepageLength;
+            return result;
+        }
 
+        private double GetReducedFall()
+        {
+            return HRiver - HExit - (Rc * DTotal);
+        }
 
+        internal static double TermLnC(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double waterViscosity)
+        {
+            double result = 0.68 - 0.1 * Math.Log(TermC(whitesConstant, beddingAngle, d70, length, permeability, waterViscosity), Math.E);
+            return result;
+        }
+        internal static double TermC(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double waterViscosity)
+        {
+            double kIntrinsic = KIntrinisc(permeability, waterViscosity);
+            double term = Math.Pow((1 / (kIntrinsic * length)), (1.0 / 3.0));
+            double result = whitesConstant * (d70 * 1.0e-6) * term;
+            return result;
+        }
 
+        internal static double KIntrinisc(double permeabilityPipingLayer, double waterViscosity)
+        {
+            double result = permeabilityPipingLayer * waterViscosity / Physics.GravityConstant;
+            return result;
+        }
 
-        //        static public double TermLnC(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double waterViscosity)
-        //        {
-        //            double result = 0.68 - 0.1 * Math.Log(TermC(whitesConstant, beddingAngle, d70, length, permeability, waterViscosity), Math.E);
-        //            return result;
-        //        }
-        //        static public double TermC(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double waterViscosity)
-        //        {
-        //            double kIntrinsic = KIntrinisc(permeability, waterViscosity);
-        //            double term = Math.Pow((1 / (kIntrinsic * length)), (1.0 / 3.0));
-        //            double result = whitesConstant * (d70 * 1.0e-6) * term;
-        //            return result;
-        //        }
-        //
-        //        static public double TermAlpha(double length, double dSandlayer)
-        //        {
-        //            double result = Math.Pow((dSandlayer / length), 0.28 / ((Math.Pow(dSandlayer / length, 2.8)) - 1));
-        //            return result;
-        //        }
-        //
-        //        static private double HcDividedByLNew(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double dSandlayer, double waterViscosity)
-        //        {
-        //            return TermAlpha(length, dSandlayer) * TermC(whitesConstant, beddingAngle, d70, length, permeability, waterViscosity) * 
-        //                CGammaPDividedByGammaW * Math.Tan(cDegreeToRadian * beddingAngle) * 
-        //                TermLnC(whitesConstant, beddingAngle, d70, length, permeability, waterViscosity);
-        //             
-        //        }
-        //
-        //        static public double CalculateHCritical(double whitesConstant, double beddingAngle, double d70, double length, double permeability, double dSandlayer, double waterViscosity)
-        //        {
-        //            double result = HcDividedByLNew(whitesConstant, beddingAngle, d70, length, permeability, dSandlayer,
-        //                                             waterViscosity) * length;
-        //            return result;
-        //        }
-        //
-        //
-        //
-        //
-        //        /// <summary>
-        //        /// Determines the required shoulder (height and length as seen from the original dike toe) 
-        //        /// </summary>
-        //        /// <param name="location"></param>
-        //        /// <param name="surfaceLine"></param>
-        //        /// <param name="soilProfile"></param>
-        //        /// <param name="waterLevel"></param>
-        //        /// <param name="point"></param>
-        //        /// <returns>The required dimensions when needed else null</returns>
-        //        public override PipingDesign CalculateDesignAtPoint(Location location, SurfaceLine2 surfaceLine, SoilProfile1D soilProfile, double waterLevel, GeometryPoint point)
-        //        {
-        //            // call base class for initializations, this will also calculate the uplift
-        //            var pipingDesign = base.CalculateDesignAtPoint(location, surfaceLine, soilProfile, waterLevel, point);
-        //            // if there is nu uplift, then there is no piping so return null
-        //            if (UpliftLocationAndResult != null)
-        //            {
-        //                // Calculate the piping safety factor using the level of the given point
-        //                var sp = CalculatePipingFactorAtLevel(location, waterLevel, point.Z);
-        //
-        //                // If too low, then determine required height and length (from uplift)
-        //                if (sp < requiredSafetyFactor)
-        //                {
-        //                    // Finally, determine the required shoulderheight
-        //                    double currentShoulderHeight = UpliftLocationAndResult.Z -
-        //                                                   surfaceLine.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder).Z;
-        //                    pipingDesign.ShoulderHeightFromToe = currentShoulderHeight + CalculateExtraShoulderHeight();
-        //                    pipingDesign.PipingLengthFromToe = UpliftLocationAndResult.X - surfaceLine.GetDikeToeInward().X;
-        //                    return pipingDesign;
-        //                }
-        //            }
-        //            return null;
-        //        }
+        internal static double TermAlpha(double length, double dSandlayer)
+        {
+            double result = Math.Pow((dSandlayer / length), 0.28 / ((Math.Pow(dSandlayer / length, 2.8)) - 1));
+            return result;
+        }
 
+        /// <summary>
+        /// Validates the input
+        /// </summary>
+        /// <returns>a filled list when errors are found else an empty list</returns>
+        public List<string> Validate()
+        {
+            var errors = new List<string>();
+            errors.AddRange(PerformValidate());
+            return errors;
+        }
+
+        private List<string> PerformValidate()
+        {
+            var errors = new List<string>();
+            if (Math.Abs(GetReducedFall()) < double.Epsilon)
+            {
+                errors.Add(Resources.PipingCalculatorSellmeijer4Forces_PerformValidate_HRiver_HExit_Rc_DTotal_Zero);
+            }
+
+            if (double.IsNaN(SeepageLength))
+            {
+                LogParameterIsNaN(errors, "SeepageLength");
+            }
+            if (double.IsNaN(HRiver))
+            {
+                LogParameterIsNaN(errors, "HRiver");
+            }
+            if (double.IsNaN(Rc))
+            {
+                LogParameterIsNaN(errors, "Rc");
+            }
+            if (Rc < 0)
+            {
+                errors.Add(Resources.PipingCalculatorSellmeijer4Forces_PerformValidate_RcLessThan0);
+            }
+            if (double.IsNaN(DTotal))
+            {
+                LogParameterIsNaN(errors, "DTotal");
+            }
+            if (double.IsNaN(AquiferHeight))
+            {
+                LogParameterIsNaN(errors, "AquiferHeight");
+            }
+            if (double.IsNaN(HExit))
+            {
+                LogParameterIsNaN(errors, "HExit");
+            }
+            if (double.IsNaN(D70))
+            {
+                LogParameterIsNaN(errors, "D70");
+            }
+            if (double.IsNaN(WhitesConstant))
+            {
+                LogParameterIsNaN(errors, "WhitesConstant");
+            }
+            if (double.IsNaN(BeddingAngle))
+            {
+                LogParameterIsNaN(errors, "BeddingAngle");
+            }
+            if (double.IsNaN(WaterViscosity))
+            {
+                LogParameterIsNaN(errors, "WaterViscosity");
+            }
+            if (double.IsNaN(PermeabilityKx))
+            {
+                LogParameterIsNaN(errors, "PermeabilityKx");
+            }
+            return errors;
+        }
+
+        private void LogParameterIsNaN(IList<string> list, string paramName)
+        {
+            var msg = string.Format(Resources.PipingCalculatorSellmeijer4Forces_LogParameterIsNaN_NaNParameterError, paramName);
+            list.Add(msg);
+        }
     }
 }
\ No newline at end of file