Index: Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Forms/PropertyClasses/ClosingStructuresFailureMechanismProperties.cs
===================================================================
diff -u -r60f9aeb20e9dee9cb4109c38187de25272c2ab06 -rc0360c53483cc463fc35192a333ec482d8777fc8
--- Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Forms/PropertyClasses/ClosingStructuresFailureMechanismProperties.cs	(.../ClosingStructuresFailureMechanismProperties.cs)	(revision 60f9aeb20e9dee9cb4109c38187de25272c2ab06)
+++ Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Forms/PropertyClasses/ClosingStructuresFailureMechanismProperties.cs	(.../ClosingStructuresFailureMechanismProperties.cs)	(revision c0360c53483cc463fc35192a333ec482d8777fc8)
@@ -50,7 +50,8 @@
 
         private const int modelFactorOvertoppingFlowPropertyIndex = 10;
         private const int modelFactorStorageVolumePropertyIndex = 11;
-        private const int modelFactorInflowVolumePropertyIndex = 12;
+        private const int modelFactorLongThresholdPropertyIndex = 12;
+        private const int modelFactorInflowVolumePropertyIndex = 13;
 
         /// <summary>
         /// Creates a new instance of <see cref="ClosingStructuresFailureMechanismProperties"/>.
@@ -80,6 +81,7 @@
                    || nameof(GravitationalAcceleration).Equals(propertyName)
                    || nameof(ModelFactorOvertoppingFlow).Equals(propertyName)
                    || nameof(ModelFactorStorageVolume).Equals(propertyName)
+                   || nameof(ModelFactorLongThreshold).Equals(propertyName)
                    || nameof(ModelFactorInflowVolume).Equals(propertyName)
                    || nameof(C).Equals(propertyName)
                    || nameof(N2A).Equals(propertyName)
@@ -243,6 +245,20 @@
         }
 
         [DynamicVisible]
+        [PropertyOrder(modelFactorLongThresholdPropertyIndex)]
+        [TypeConverter(typeof(ExpandableObjectConverter))]
+        [ResourcesCategory(typeof(RingtoetsCommonFormsResources), nameof(RingtoetsCommonFormsResources.Categories_ModelSettings))]
+        [ResourcesDisplayName(typeof(RingtoetsCommonFormsResources), nameof(RingtoetsCommonFormsResources.StructuresInputFailureMechanismContext_ModelFactorLongThreshold_DisplayName))]
+        [ResourcesDescription(typeof(RingtoetsCommonFormsResources), nameof(RingtoetsCommonFormsResources.StructuresInputFailureMechanismContext_ModelFactorLongThreshold_Description))]
+        public NormalDistributionProperties ModelFactorLongThreshold
+        {
+            get
+            {
+                return new NormalDistributionProperties(data.GeneralInput.ModelFactorLongThreshold);
+            }
+        }
+
+        [DynamicVisible]
         [PropertyOrder(modelFactorInflowVolumePropertyIndex)]
         [ResourcesCategory(typeof(RingtoetsCommonFormsResources), nameof(RingtoetsCommonFormsResources.Categories_ModelSettings))]
         [ResourcesDisplayName(typeof(RingtoetsCommonFormsResources), nameof(RingtoetsCommonFormsResources.StructuresInputFailureMechanismContext_ModelFactorInflowVolume_DisplayName))]
Index: Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.Forms.Test/PropertyClasses/ClosingStructuresFailureMechanismPropertiesTest.cs
===================================================================
diff -u -r84fd247421bee82f431195fd74d998bf8b87fa52 -rc0360c53483cc463fc35192a333ec482d8777fc8
--- Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.Forms.Test/PropertyClasses/ClosingStructuresFailureMechanismPropertiesTest.cs	(.../ClosingStructuresFailureMechanismPropertiesTest.cs)	(revision 84fd247421bee82f431195fd74d998bf8b87fa52)
+++ Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.Forms.Test/PropertyClasses/ClosingStructuresFailureMechanismPropertiesTest.cs	(.../ClosingStructuresFailureMechanismPropertiesTest.cs)	(revision c0360c53483cc463fc35192a333ec482d8777fc8)
@@ -48,7 +48,8 @@
 
         private const int modelFactorOvertoppingFlowPropertyIndex = 9;
         private const int modelFactorStorageVolumePropertyIndex = 10;
-        private const int modelFactorInflowVolumePropertyIndex = 11;
+        private const int modelFactorLongThresholdPropertyIndex = 11;
+        private const int modelFactorInflowVolumePropertyIndex = 12;
 
         [Test]
         public void Constructor_DataNull_ThrowArgumentNullException()
@@ -97,6 +98,8 @@
             Assert.AreEqual(generalInput.ModelFactorOvertoppingFlow.StandardDeviation, properties.ModelFactorOvertoppingFlow.StandardDeviation);
             Assert.AreEqual(generalInput.ModelFactorStorageVolume.Mean, properties.ModelFactorStorageVolume.Mean);
             Assert.AreEqual(generalInput.ModelFactorStorageVolume.StandardDeviation, properties.ModelFactorStorageVolume.StandardDeviation);
+            Assert.AreEqual(generalInput.ModelFactorLongThreshold.Mean, properties.ModelFactorLongThreshold.Mean);
+            Assert.AreEqual(generalInput.ModelFactorLongThreshold.StandardDeviation, properties.ModelFactorLongThreshold.StandardDeviation);
             Assert.AreEqual(generalInput.ModelFactorInflowVolume, properties.ModelFactorInflowVolume);
         }
 
@@ -116,7 +119,7 @@
             const string modelSettingsCategory = "Modelinstellingen";
 
             PropertyDescriptorCollection dynamicProperties = PropertiesTestHelper.GetAllVisiblePropertyDescriptors(properties);
-            Assert.AreEqual(12, dynamicProperties.Count);
+            Assert.AreEqual(13, dynamicProperties.Count);
 
             PropertyDescriptor nameProperty = dynamicProperties[namePropertyIndex];
             PropertiesTestHelper.AssertRequiredPropertyDescriptorProperties(nameProperty,
@@ -196,6 +199,14 @@
                                                                             "Modelfactor kombergend vermogen.",
                                                                             true);
 
+            PropertyDescriptor modelFactorLongThresholdProperty = dynamicProperties[modelFactorLongThresholdPropertyIndex];
+            Assert.IsInstanceOf<ExpandableObjectConverter>(modelFactorLongThresholdProperty.Converter);
+            PropertiesTestHelper.AssertRequiredPropertyDescriptorProperties(modelFactorLongThresholdProperty,
+                                                                            modelSettingsCategory,
+                                                                            "Modelfactor lange overlaat[-]",
+                                                                            "Modelfactor voor een lange overlaat.",
+                                                                            true);
+
             PropertyDescriptor modelFactorInflowVolumeProperty = dynamicProperties[modelFactorInflowVolumePropertyIndex];
             PropertiesTestHelper.AssertRequiredPropertyDescriptorProperties(modelFactorInflowVolumeProperty,
                                                                             modelSettingsCategory,
@@ -326,6 +337,7 @@
             Assert.AreEqual(isRelevant, properties.DynamicVisibleValidationMethod(nameof(properties.GravitationalAcceleration)));
             Assert.AreEqual(isRelevant, properties.DynamicVisibleValidationMethod(nameof(properties.ModelFactorOvertoppingFlow)));
             Assert.AreEqual(isRelevant, properties.DynamicVisibleValidationMethod(nameof(properties.ModelFactorStorageVolume)));
+            Assert.AreEqual(isRelevant, properties.DynamicVisibleValidationMethod(nameof(properties.ModelFactorLongThreshold)));
             Assert.AreEqual(isRelevant, properties.DynamicVisibleValidationMethod(nameof(properties.ModelFactorInflowVolume)));
 
             Assert.IsTrue(properties.DynamicVisibleValidationMethod(null));
Index: Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.Designer.cs
===================================================================
diff -u -r60f9aeb20e9dee9cb4109c38187de25272c2ab06 -rc0360c53483cc463fc35192a333ec482d8777fc8
--- Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 60f9aeb20e9dee9cb4109c38187de25272c2ab06)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision c0360c53483cc463fc35192a333ec482d8777fc8)
@@ -1,4 +1,4 @@
-// Copyright (C) Stichting Deltares 2017. All rights reserved.
+// Copyright (C) Stichting Deltares 2017. All rights reserved.
 //
 // This file is part of Ringtoets.
 //
@@ -3641,6 +3641,24 @@
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to Modelfactor voor een lange overlaat..
+        /// </summary>
+        public static string StructuresInputFailureMechanismContext_ModelFactorLongThreshold_Description {
+            get {
+                return ResourceManager.GetString("StructuresInputFailureMechanismContext_ModelFactorLongThreshold_Description", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Modelfactor lange overlaat[-].
+        /// </summary>
+        public static string StructuresInputFailureMechanismContext_ModelFactorLongThreshold_DisplayName {
+            get {
+                return ResourceManager.GetString("StructuresInputFailureMechanismContext_ModelFactorLongThreshold_DisplayName", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to Modelfactor voor het overslagdebiet..
         /// </summary>
         public static string StructuresInputFailureMechanismContext_ModelFactorOvertoppingFlow_Description {
Index: Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.resx
===================================================================
diff -u -r60f9aeb20e9dee9cb4109c38187de25272c2ab06 -rc0360c53483cc463fc35192a333ec482d8777fc8
--- Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision 60f9aeb20e9dee9cb4109c38187de25272c2ab06)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision c0360c53483cc463fc35192a333ec482d8777fc8)
@@ -1458,4 +1458,10 @@
   <data name="HydraulicLoads_Calculate_All_ToolTip" xml:space="preserve">
     <value>Alle hydraulische belastingen berekenen.</value>
   </data>
+  <data name="StructuresInputFailureMechanismContext_ModelFactorLongThreshold_DisplayName" xml:space="preserve">
+    <value>Modelfactor lange overlaat[-]</value>
+  </data>
+  <data name="StructuresInputFailureMechanismContext_ModelFactorLongThreshold_Description" xml:space="preserve">
+    <value>Modelfactor voor een lange overlaat.</value>
+  </data>
 </root>
\ No newline at end of file