Index: Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/IAssessmentSection.cs
===================================================================
diff -u -rfb2a074d7c2568900f42fee02ef4a3a72fe40ea3 -rcc686ef967b8411d7c88a8b93afe614fa936e4b2
--- Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/IAssessmentSection.cs	(.../IAssessmentSection.cs)	(revision fb2a074d7c2568900f42fee02ef4a3a72fe40ea3)
+++ Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/IAssessmentSection.cs	(.../IAssessmentSection.cs)	(revision cc686ef967b8411d7c88a8b93afe614fa936e4b2)
@@ -77,42 +77,42 @@
         /// <summary>
         /// Gets the water level calculations corresponding to the factorized signaling norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm { get; }
 
         /// <summary>
         /// Gets the water level calculations corresponding to the signaling norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm { get; }
 
         /// <summary>
         /// Gets the water level calculations corresponding to the lower limit norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm { get; }
 
         /// <summary>
         /// Gets the water level calculations corresponding to the factorized lower limit norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm { get; }
 
         /// <summary>
         /// Gets the wave height calculations corresponding to the factorized signaling norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm { get; }
 
         /// <summary>
         /// Gets the wave height calculations corresponding to the signaling norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm { get; }
 
         /// <summary>
         /// Gets the wave height calculations corresponding to the lower limit norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm { get; }
 
         /// <summary>
         /// Gets the wave height calculations corresponding to the factorized lower limit norm.
         /// </summary>
-        IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm { get; }
+        IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm { get; }
 
         /// <summary>
         /// Gets the failure mechanisms corresponding to the assessment section.
Index: Ringtoets/Common/test/Ringtoets.Common.Data.TestUtil/ObservableTestAssessmentSectionStub.cs
===================================================================
diff -u -rfb2a074d7c2568900f42fee02ef4a3a72fe40ea3 -rcc686ef967b8411d7c88a8b93afe614fa936e4b2
--- Ringtoets/Common/test/Ringtoets.Common.Data.TestUtil/ObservableTestAssessmentSectionStub.cs	(.../ObservableTestAssessmentSectionStub.cs)	(revision fb2a074d7c2568900f42fee02ef4a3a72fe40ea3)
+++ Ringtoets/Common/test/Ringtoets.Common.Data.TestUtil/ObservableTestAssessmentSectionStub.cs	(.../ObservableTestAssessmentSectionStub.cs)	(revision cc686ef967b8411d7c88a8b93afe614fa936e4b2)
@@ -49,14 +49,14 @@
 
             HydraulicBoundaryDatabase = new HydraulicBoundaryDatabase();
 
-            WaterLevelCalculationsForFactorizedSignalingNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaterLevelCalculationsForSignalingNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaterLevelCalculationsForLowerLimitNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaterLevelCalculationsForFactorizedLowerLimitNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaveHeightCalculationsForFactorizedSignalingNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaveHeightCalculationsForSignalingNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaveHeightCalculationsForLowerLimitNorm = new HydraulicBoundaryLocationCalculation[0];
-            WaveHeightCalculationsForFactorizedLowerLimitNorm = new HydraulicBoundaryLocationCalculation[0];
+            WaterLevelCalculationsForFactorizedSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaterLevelCalculationsForSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaterLevelCalculationsForLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaterLevelCalculationsForFactorizedLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaveHeightCalculationsForFactorizedSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaveHeightCalculationsForSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaveHeightCalculationsForLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+            WaveHeightCalculationsForFactorizedLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
         }
 
         public string Id { get; }
@@ -67,14 +67,14 @@
         public FailureMechanismContribution FailureMechanismContribution { get; }
         public HydraulicBoundaryDatabase HydraulicBoundaryDatabase { get; }
         public BackgroundData BackgroundData { get; set; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm { get; }
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm { get; }
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm { get; }
 
         public IEnumerable<IFailureMechanism> GetFailureMechanisms()
         {
Index: Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs
===================================================================
diff -u -r47a3071db27d6f39d182111938d76a4efdda0f6f -rcc686ef967b8411d7c88a8b93afe614fa936e4b2
--- Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs	(.../AssessmentSection.cs)	(revision 47a3071db27d6f39d182111938d76a4efdda0f6f)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs	(.../AssessmentSection.cs)	(revision cc686ef967b8411d7c88a8b93afe614fa936e4b2)
@@ -51,14 +51,15 @@
         private const double defaultNorm = 1.0 / 30000;
         private const RingtoetsWellKnownTileSource defaultWellKnownTileSource = RingtoetsWellKnownTileSource.BingAerial;
 
-        private readonly IList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForFactorizedSignalingNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForSignalingNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForLowerLimitNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForFactorizedLowerLimitNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForFactorizedSignalingNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForSignalingNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForLowerLimitNorm = new List<HydraulicBoundaryLocationCalculation>();
-        private readonly IList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForFactorizedLowerLimitNorm = new List<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForFactorizedSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waterLevelCalculationsForFactorizedLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForFactorizedSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForSignalingNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+        private readonly ObservableList<HydraulicBoundaryLocationCalculation> waveHeightCalculationsForFactorizedLowerLimitNorm = new ObservableList<HydraulicBoundaryLocationCalculation>();
+
         private ReferenceLine referenceLine;
 
         /// <summary>
@@ -210,63 +211,63 @@
         /// </summary>
         public TechnicalInnovationFailureMechanism TechnicalInnovation { get; }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedSignalingNorm
         {
             get
             {
                 return waterLevelCalculationsForFactorizedSignalingNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForSignalingNorm
         {
             get
             {
                 return waterLevelCalculationsForSignalingNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForLowerLimitNorm
         {
             get
             {
                 return waterLevelCalculationsForLowerLimitNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaterLevelCalculationsForFactorizedLowerLimitNorm
         {
             get
             {
                 return waterLevelCalculationsForFactorizedLowerLimitNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedSignalingNorm
         {
             get
             {
                 return waveHeightCalculationsForFactorizedSignalingNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForSignalingNorm
         {
             get
             {
                 return waveHeightCalculationsForSignalingNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForLowerLimitNorm
         {
             get
             {
                 return waveHeightCalculationsForLowerLimitNorm;
             }
         }
 
-        public IEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm
+        public IObservableEnumerable<HydraulicBoundaryLocationCalculation> WaveHeightCalculationsForFactorizedLowerLimitNorm
         {
             get
             {