Index: Riskeer/GrassCoverErosionOutwards/src/Riskeer.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsDataSynchronizationService.cs
===================================================================
diff -u -r9e9976818f1b446948c3bf815cafe2e023f98ac1 -rc802ae879d8c6934c22516de3965f7a4cace2982
--- Riskeer/GrassCoverErosionOutwards/src/Riskeer.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsDataSynchronizationService.cs	(.../GrassCoverErosionOutwardsDataSynchronizationService.cs)	(revision 9e9976818f1b446948c3bf815cafe2e023f98ac1)
+++ Riskeer/GrassCoverErosionOutwards/src/Riskeer.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsDataSynchronizationService.cs	(.../GrassCoverErosionOutwardsDataSynchronizationService.cs)	(revision c802ae879d8c6934c22516de3965f7a4cace2982)
@@ -36,22 +36,30 @@
     public static class GrassCoverErosionOutwardsDataSynchronizationService
     {
         /// <summary>
-        /// Clears the <see cref="HydraulicBoundaryLocation"/> and output for all the wave conditions calculations
-        /// in the <see cref="GrassCoverErosionOutwardsFailureMechanism"/>.
+        /// Clears the <see cref="HydraulicBoundaryLocation"/> and output for the wave conditions calculations
+        /// in the <see cref="GrassCoverErosionOutwardsFailureMechanism"/> that uses an <see cref="HydraulicBoundaryLocation"/>
+        /// from <paramref name="hydraulicBoundaryLocations"/>.
         /// </summary>
         /// <param name="failureMechanism">The <see cref="GrassCoverErosionOutwardsFailureMechanism"/>
         /// which contains the calculations.</param>
+        /// <param name="hydraulicBoundaryLocations">The hydraulic boundary locations to clear for.</param>
         /// <returns>An <see cref="IEnumerable{T}"/> of objects which are affected by removal of data.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="failureMechanism"/>
         /// is <c>null</c>.</exception>
         public static IEnumerable<IObservable> ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(
-            GrassCoverErosionOutwardsFailureMechanism failureMechanism)
+            GrassCoverErosionOutwardsFailureMechanism failureMechanism,
+            IEnumerable<HydraulicBoundaryLocation> hydraulicBoundaryLocations)
         {
             if (failureMechanism == null)
             {
                 throw new ArgumentNullException(nameof(failureMechanism));
             }
 
+            if (hydraulicBoundaryLocations == null)
+            {
+                throw new ArgumentNullException(nameof(hydraulicBoundaryLocations));
+            }
+
             var affectedItems = new List<IObservable>();
             foreach (GrassCoverErosionOutwardsWaveConditionsCalculation calculation in failureMechanism.Calculations.Cast<GrassCoverErosionOutwardsWaveConditionsCalculation>())
             {
Index: Riskeer/GrassCoverErosionOutwards/test/Riskeer.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs
===================================================================
diff -u -r9e9976818f1b446948c3bf815cafe2e023f98ac1 -rc802ae879d8c6934c22516de3965f7a4cace2982
--- Riskeer/GrassCoverErosionOutwards/test/Riskeer.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs	(.../GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs)	(revision 9e9976818f1b446948c3bf815cafe2e023f98ac1)
+++ Riskeer/GrassCoverErosionOutwards/test/Riskeer.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs	(.../GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs)	(revision c802ae879d8c6934c22516de3965f7a4cace2982)
@@ -41,14 +41,27 @@
         public void ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations_FailureMechanismNull_ThrowsArgumentNullException()
         {
             // Call
-            void Call() => GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(null);
+            void Call() => GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(
+                null, Enumerable.Empty<HydraulicBoundaryLocation>());
 
             // Assert
             var exception = Assert.Throws<ArgumentNullException>(Call);
             Assert.AreEqual("failureMechanism", exception.ParamName);
         }
 
         [Test]
+        public void ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations_HydraulicBoundaryLocationsNull_ThrowsArgumentNullException()
+        {
+            // Call
+            void Call() => GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(
+                new GrassCoverErosionOutwardsFailureMechanism(), null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("hydraulicBoundaryLocations", exception.ParamName);
+        }
+
+        [Test]
         public void ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations_WithVariousCalculations_ClearsOutputAndReturnsAffectedObjects()
         {
             // Setup
@@ -63,8 +76,8 @@
                                                                           .ToArray();
 
             // Call
-            IEnumerable<IObservable> affectedItems =
-                GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(failureMechanism);
+            IEnumerable<IObservable> affectedItems = GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(
+                failureMechanism, Enumerable.Empty<HydraulicBoundaryLocation>());
 
             // Assert
             // Note: To make sure the clear is performed regardless of what is done with
Index: Riskeer/Integration/src/Riskeer.Integration.Service/RiskeerDataSynchronizationService.cs
===================================================================
diff -u -rfa4145437e47ac6c2a2b864ccd83a9c62701b335 -rc802ae879d8c6934c22516de3965f7a4cace2982
--- Riskeer/Integration/src/Riskeer.Integration.Service/RiskeerDataSynchronizationService.cs	(.../RiskeerDataSynchronizationService.cs)	(revision fa4145437e47ac6c2a2b864ccd83a9c62701b335)
+++ Riskeer/Integration/src/Riskeer.Integration.Service/RiskeerDataSynchronizationService.cs	(.../RiskeerDataSynchronizationService.cs)	(revision c802ae879d8c6934c22516de3965f7a4cace2982)
@@ -106,7 +106,8 @@
                                                         waveImpactAsphaltCoverFailureMechanism, hydraulicBoundaryLocations));
                         break;
                     case GrassCoverErosionOutwardsFailureMechanism grassCoverErosionOutwardsFailureMechanism:
-                        changedObservables.AddRange(GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(grassCoverErosionOutwardsFailureMechanism));
+                        changedObservables.AddRange(GrassCoverErosionOutwardsDataSynchronizationService.ClearAllWaveConditionsCalculationOutputAndHydraulicBoundaryLocations(
+                                                        grassCoverErosionOutwardsFailureMechanism, hydraulicBoundaryLocations));
                         break;
                     case HeightStructuresFailureMechanism heightStructuresFailureMechanism:
                         changedObservables.AddRange(HeightStructuresDataSynchronizationService.ClearAllCalculationOutputAndHydraulicBoundaryLocations(heightStructuresFailureMechanism));