Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/PropertyClasses/GrassCoverErosionOutwardsFailureMechanismPropertiesTest.cs
===================================================================
diff -u -r04fe7ebded76d25890b035c734edd538e63897b4 -r5d7e0a2834c689c2221b1eca13876a8eef85fb95
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/PropertyClasses/GrassCoverErosionOutwardsFailureMechanismPropertiesTest.cs	(.../GrassCoverErosionOutwardsFailureMechanismPropertiesTest.cs)	(revision 04fe7ebded76d25890b035c734edd538e63897b4)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/PropertyClasses/GrassCoverErosionOutwardsFailureMechanismPropertiesTest.cs	(.../GrassCoverErosionOutwardsFailureMechanismPropertiesTest.cs)	(revision 5d7e0a2834c689c2221b1eca13876a8eef85fb95)
@@ -22,12 +22,14 @@
 using System;
 using System.ComponentModel;
 using Core.Common.Base;
+using Core.Common.Base.Data;
 using Core.Common.Gui.PropertyBag;
 using NUnit.Framework;
 using Rhino.Mocks;
 using Ringtoets.GrassCoverErosionOutwards.Data;
 using Ringtoets.GrassCoverErosionOutwards.Data.Properties;
 using Ringtoets.GrassCoverErosionOutwards.Forms.PropertyClasses;
+using Ringtoets.HydraRing.Data;
 
 namespace Ringtoets.GrassCoverErosionOutwards.Forms.Test.PropertyClasses
 {
@@ -124,7 +126,54 @@
             Assert.AreEqual("N [-]", lengthEffectProperty.DisplayName);
             Assert.AreEqual("De parameter 'N' die gebruikt wordt om het lengte-effect mee te nemen in een semi-probabilistische beoordeling.", lengthEffectProperty.Description);
         }
+        
+        [Test]
+        [TestCase(1)]
+        [TestCase(10)]
+        [TestCase(20)]
+        public void LengthEffect_ValueSet_HydraulicBoundaryLocationsCleared(int value)
+        {
+            // Setup
+            var mockRepository = new MockRepository();
+            var observerMock = mockRepository.StrictMock<IObserver>();
+            observerMock.Expect(o => o.UpdateObserver());
+            mockRepository.ReplayAll();
 
+            var hydraulicLocation = new HydraulicBoundaryLocation(1, string.Empty, 0, 0);
+            var grassCoverErosionOutwardsHydraulicBoundaryLocation = new GrassCoverErosionOutwardsHydraulicBoundaryLocation(hydraulicLocation)
+            {
+                DesignWaterLevel = (RoundedDouble)3.8,
+                WaveHeight = (RoundedDouble)5.2
+            };
+
+            var failureMechanism = new GrassCoverErosionOutwardsFailureMechanism
+            {
+                GrassCoverErosionOutwardsHydraulicBoundaryLocations =
+                {
+                    grassCoverErosionOutwardsHydraulicBoundaryLocation
+                }
+            };
+
+            failureMechanism.Attach(observerMock);
+
+            var properties = new GrassCoverErosionOutwardsFailureMechanismProperties
+            {
+                Data = failureMechanism
+            };
+
+            // Call
+            properties.LengthEffect = value;
+
+            // Assert
+            Assert.AreEqual(value, properties.LengthEffect);
+            Assert.AreEqual(value, failureMechanism.GeneralInput.N);
+            Assert.IsNaN(grassCoverErosionOutwardsHydraulicBoundaryLocation.DesignWaterLevel);
+            Assert.IsNaN(grassCoverErosionOutwardsHydraulicBoundaryLocation.WaveHeight);
+            Assert.AreEqual(CalculationConvergence.NotCalculated, grassCoverErosionOutwardsHydraulicBoundaryLocation.DesignWaterLevelCalculationConvergence);
+            Assert.AreEqual(CalculationConvergence.NotCalculated, grassCoverErosionOutwardsHydraulicBoundaryLocation.WaveHeightCalculationConvergence);
+            mockRepository.VerifyAll();
+        }
+
         private const int namePropertyIndex = 0;
         private const int codePropertyIndex = 1;
         private const int lengthEffectPropertyIndex = 2;