Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.Designer.cs
===================================================================
diff -u -r77158a296743c3b3457336706fdbea047daf4886 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 77158a296743c3b3457336706fdbea047daf4886)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -1,7 +1,7 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by a tool.
-//     Runtime Version:4.0.30319.34209
+//     Runtime Version:4.0.30319.42000
 //
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.
@@ -197,7 +197,7 @@
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Lijst met geometrie punten..
+        ///   Looks up a localized string similar to Lijst met geometriepunten..
         /// </summary>
         public static string DikeGeometry_Coordinates_Description {
             get {
Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.resx
===================================================================
diff -u -r77158a296743c3b3457336706fdbea047daf4886 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision 77158a296743c3b3457336706fdbea047daf4886)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -185,7 +185,7 @@
     <value>Dijkgeometrie</value>
   </data>
   <data name="DikeGeometry_Coordinates_Description" xml:space="preserve">
-    <value>Lijst met geometrie punten.</value>
+    <value>Lijst met geometriepunten.</value>
   </data>
   <data name="DikeGeometry_Coordinates_DisplayName" xml:space="preserve">
     <value>Coördinaten [m]</value>
Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs
===================================================================
diff -u -re2991a38a1982398a6cbb35e38e534e26ba8930d -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs	(.../GrassCoverErosionInwardsGuiPlugin.cs)	(revision e2991a38a1982398a6cbb35e38e534e26ba8930d)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs	(.../GrassCoverErosionInwardsGuiPlugin.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -129,7 +129,7 @@
                 failureMechanismSection.Name, // TODO: Provide name of reference line instead
                 HydraRingTimeIntegrationSchemeType.FBC,
                 HydraRingUncertaintiesType.All,
-                new OvertoppingCalculationInput(hydraulicBoundaryLocationId, new HydraRingSection(hydraulicBoundaryLocationId, failureMechanismSection.Name, sectionLength, inwardsInput.Orientation),
+                new OvertoppingCalculationInput(hydraulicBoundaryLocationId, new HydraRingSection(1, failureMechanismSection.Name, sectionLength, inwardsInput.Orientation),
                                                 inwardsInput.DikeHeight,
                                                 inwardsInput.CriticalOvertoppingModelFactor,
                                                 inwardsInput.FbFactor.Mean, inwardsInput.FbFactor.StandardDeviation,
Index: Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/PropertyClasses/DikeGeometryPropertiesTest.cs
===================================================================
diff -u -reaa8b3e276e1a0a6a4d0a2f96016879d8d12d394 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/PropertyClasses/DikeGeometryPropertiesTest.cs	(.../DikeGeometryPropertiesTest.cs)	(revision eaa8b3e276e1a0a6a4d0a2f96016879d8d12d394)
+++ Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/PropertyClasses/DikeGeometryPropertiesTest.cs	(.../DikeGeometryPropertiesTest.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -106,7 +106,7 @@
             Assert.IsNotNull(coordinatesProperty);
             Assert.IsTrue(coordinatesProperty.IsReadOnly);
             Assert.AreEqual("Coördinaten [m]", coordinatesProperty.DisplayName);
-            Assert.AreEqual("Lijst met geometrie punten.", coordinatesProperty.Description);
+            Assert.AreEqual("Lijst met geometriepunten.", coordinatesProperty.Description);
 
             PropertyDescriptor numberOfCoordinatesDikeHeightProperty = dynamicProperties[numberOfCoordinatesDikeHeightPropertyIndex];
             Assert.IsNotNull(numberOfCoordinatesDikeHeightProperty);
Index: Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Data/HydraRingSection.cs
===================================================================
diff -u -rdec46d5efaad5332ffb2a96e67ec11209ddc5515 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Data/HydraRingSection.cs	(.../HydraRingSection.cs)	(revision dec46d5efaad5332ffb2a96e67ec11209ddc5515)
+++ Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Data/HydraRingSection.cs	(.../HydraRingSection.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -34,7 +34,7 @@
         /// <summary>
         /// Creates a new instance of the <see cref="HydraRingSection"/> class.
         /// </summary>
-        /// <param name="sectionId">The id of the section.</param>
+        /// <param name="sectionId">The unique identifier of the section.</param>
         /// <param name="sectionName">The name of the section.</param>
         /// <param name="sectionLength">The length of the section.</param>
         /// <param name="crossSectionNormal">The normal of the cross section.</param>
Index: Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Services/HydraRingConfigurationService.cs
===================================================================
diff -u -r5685b03c0cf1bac591de0ae2c23483537f6f7691 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Services/HydraRingConfigurationService.cs	(.../HydraRingConfigurationService.cs)	(revision 5685b03c0cf1bac591de0ae2c23483537f6f7691)
+++ Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Services/HydraRingConfigurationService.cs	(.../HydraRingConfigurationService.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -120,8 +120,15 @@
         /// Adds Hydra-Ring calculation input to the configuration.
         /// </summary>
         /// <param name="hydraRingCalculationInput">The calculation input to add to the configuration.</param>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="hydraRingCalculationInput"/> with 
+        /// the same <see cref="HydraRingSection.SectionId"/> has already been added.</exception>
         public void AddHydraRingCalculationInput(HydraRingCalculationInput hydraRingCalculationInput)
         {
+            var conflictingIds = hydraRingCalculationInputs.Where(h => h.Section.SectionId == hydraRingCalculationInput.Section.SectionId);
+            if (conflictingIds.Any())
+            {
+                throw new ArgumentException(@"Section id is not unique", "hydraRingCalculationInput");
+            }
             hydraRingCalculationInputs.Add(hydraRingCalculationInput);
         }
 
Index: Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Services/HydraRingConfigurationServiceTest.cs
===================================================================
diff -u -r5685b03c0cf1bac591de0ae2c23483537f6f7691 -r1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba
--- Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Services/HydraRingConfigurationServiceTest.cs	(.../HydraRingConfigurationServiceTest.cs)	(revision 5685b03c0cf1bac591de0ae2c23483537f6f7691)
+++ Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Services/HydraRingConfigurationServiceTest.cs	(.../HydraRingConfigurationServiceTest.cs)	(revision 1c5621a4920e3d5821ccbf3b5d32a6eeb7658cba)
@@ -21,6 +21,7 @@
 
 using System;
 using System.Collections.Generic;
+using Core.Common.TestUtil;
 using NUnit.Framework;
 using Ringtoets.HydraRing.Calculation.Data;
 using Ringtoets.HydraRing.Calculation.Data.Input;
@@ -44,6 +45,23 @@
         }
 
         [Test]
+        public void AddHydraRingCalculationInput_DuplicateSectionId_ThrowsArgumentException()
+        {
+            // Setup
+            var hydraRingConfigurationService = new HydraRingConfigurationService("34-1", HydraRingTimeIntegrationSchemeType.NTI, HydraRingUncertaintiesType.Model);
+            var calculationInput = new HydraRingCalculationInputImplementation(1, 2);
+
+            // Precondition
+            hydraRingConfigurationService.AddHydraRingCalculationInput(calculationInput);
+
+            // Call
+            TestDelegate test = () => hydraRingConfigurationService.AddHydraRingCalculationInput(calculationInput);
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentException>(test, "Section id is not unique");
+        }
+
+        [Test]
         public void GenerateDataBaseCreationScript_SingleHydraRingCalculationInputAddedToConfiguration_ReturnsExpectedCreationScript()
         {
             // Setup