Index: dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/InterfaceTests.cs
===================================================================
diff -u -r304 -r312
--- dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/InterfaceTests.cs	(.../InterfaceTests.cs)	(revision 304)
+++ dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/InterfaceTests.cs	(.../InterfaceTests.cs)	(revision 312)
@@ -11,10 +11,10 @@
     public class InterfaceTests
     {
         [Test]
-        [ExpectedException(typeof(Exception))]
+        [ExpectedException(typeof(InterfaceException))]
         public void ThrowWhenCalledWithEmptyParameters()
         {
-            throw new Exception();
+            var damInterface = new Interface("");
         }
     }
 }
Index: dam engine/trunk/src/Deltares.DamEngine.Interface/Deltares.DamEngine.Interface.csproj
===================================================================
diff -u -r302 -r312
--- dam engine/trunk/src/Deltares.DamEngine.Interface/Deltares.DamEngine.Interface.csproj	(.../Deltares.DamEngine.Interface.csproj)	(revision 302)
+++ dam engine/trunk/src/Deltares.DamEngine.Interface/Deltares.DamEngine.Interface.csproj	(.../Deltares.DamEngine.Interface.csproj)	(revision 312)
@@ -63,6 +63,7 @@
       <Link>Properties\GlobalAssemblyInfo.cs</Link>
     </Compile>
     <Compile Include="Interface.cs" />
+    <Compile Include="InterfaceException.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>
Index: dam engine/trunk/src/Deltares.DamEngine.Interface/Interface.cs
===================================================================
diff -u -r305 -r312
--- dam engine/trunk/src/Deltares.DamEngine.Interface/Interface.cs	(.../Interface.cs)	(revision 305)
+++ dam engine/trunk/src/Deltares.DamEngine.Interface/Interface.cs	(.../Interface.cs)	(revision 312)
@@ -14,7 +14,10 @@
         /// <param name="modelInput">The model input.</param>
         public Interface(string modelInput)
         {
-            
+            if (String.IsNullOrEmpty(modelInput))
+            {
+                throw new InterfaceException("Error: empty input string");
+            }
         }
 
         /// <summary>
Index: dam engine/trunk/src/Deltares.DamEngine.Interface/InterfaceException.cs
===================================================================
diff -u
--- dam engine/trunk/src/Deltares.DamEngine.Interface/InterfaceException.cs	(revision 0)
+++ dam engine/trunk/src/Deltares.DamEngine.Interface/InterfaceException.cs	(revision 312)
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Deltares.DamEngine.Interface
+{
+    public class InterfaceException: Exception
+    {
+        public InterfaceException(string message) : base(message) { }
+    }
+}
Index: dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/Deltares.DamEngine.Interface.Tests.csproj
===================================================================
diff -u -r304 -r312
--- dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/Deltares.DamEngine.Interface.Tests.csproj	(.../Deltares.DamEngine.Interface.Tests.csproj)	(revision 304)
+++ dam engine/trunk/src/Deltares.DamEngine.Interface.Tests/Deltares.DamEngine.Interface.Tests.csproj	(.../Deltares.DamEngine.Interface.Tests.csproj)	(revision 312)
@@ -68,6 +68,12 @@
     <Compile Include="InterfaceTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Deltares.DamEngine.Interface\Deltares.DamEngine.Interface.csproj">
+      <Project>{750464a3-cbfa-429f-920e-b430867f1120}</Project>
+      <Name>Deltares.DamEngine.Interface</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.