Index: Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Service/ClosingStructuresCalculationService.cs
===================================================================
diff -u -r048ca910b1d2e3ddcd6a59eea8b6ccf2bdf63116 -r83024e3b1086e1dba93b83df874bd4781f67aa63
--- Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Service/ClosingStructuresCalculationService.cs	(.../ClosingStructuresCalculationService.cs)	(revision 048ca910b1d2e3ddcd6a59eea8b6ccf2bdf63116)
+++ Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Service/ClosingStructuresCalculationService.cs	(.../ClosingStructuresCalculationService.cs)	(revision 83024e3b1086e1dba93b83df874bd4781f67aa63)
@@ -33,6 +33,8 @@
 using Ringtoets.HydraRing.Calculation.Data;
 using Ringtoets.HydraRing.Calculation.Data.Input.Structures;
 using Ringtoets.HydraRing.Calculation.Parsers;
+using Ringtoets.HydraRing.IO;
+using RingtoetsCommonServiceResources = Ringtoets.Common.Service.Properties.Resources;
 
 namespace Ringtoets.ClosingStructures.Service
 {
@@ -62,7 +64,8 @@
                               IAssessmentSection assessmentSection,
                               FailureMechanismSection failureMechanismSection,
                               GeneralClosingStructuresInput generalInput,
-                              double failureMechanismContribution, string hlcdDirectory)
+                              double failureMechanismContribution,
+                              string hlcdDirectory)
         {
             var calculationName = calculation.Name;
 
@@ -127,10 +130,11 @@
         public bool Validate(ClosingStructuresCalculation calculation, IAssessmentSection assessmentSection)
         {
             CalculationServiceHelper.LogValidationBeginTime(calculation.Name);
-            //TODO: Validate all the input parameters here, see WTI-926
+            var messages = ValidateInput(calculation.InputParameters, assessmentSection);
+            CalculationServiceHelper.LogMessagesAsError(RingtoetsCommonServiceResources.Error_in_validation_0, messages);
             CalculationServiceHelper.LogValidationEndTime(calculation.Name);
 
-            return true;
+            return !messages.Any();
         }
 
         private static StructuresClosureVerticalWallCalculationInput CreateClosureVerticalWallCalculationInput(ClosingStructuresCalculation calculation,
@@ -231,5 +235,24 @@
         {
             return input.UseBreakWater ? new HydraRingBreakWater((int) input.BreakWater.Type, input.BreakWater.Height) : null;
         }
+
+        private static string[] ValidateInput(ClosingStructuresInput inputParameters, IAssessmentSection assessmentSection)
+        {
+            var validationResult = new List<string>();
+
+            var validationProblem = HydraulicDatabaseHelper.ValidatePathForCalculation(assessmentSection.HydraulicBoundaryDatabase.FilePath);
+            if (!string.IsNullOrEmpty(validationProblem))
+            {
+                validationResult.Add(validationProblem);
+                return validationResult.ToArray();
+            }
+
+            if (inputParameters.HydraulicBoundaryLocation == null)
+            {
+                validationResult.Add(RingtoetsCommonServiceResources.CalculationService_ValidateInput_No_hydraulic_boundary_location_selected);
+            }
+			//TODO: Validate all the input parameters here, see WTI-926
+            return validationResult.ToArray();
+        }
     }
 }
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