Index: Ringtoets/Common/src/Ringtoets.Common.IO/FileImporters/StructuresImporter.cs
===================================================================
diff -u -r2f6400116d57c2b49f7089dbc9c8cd935c185a36 -r3e3087bd9c43ca5a3910438b3c9daf0defcb09bf
--- Ringtoets/Common/src/Ringtoets.Common.IO/FileImporters/StructuresImporter.cs	(.../StructuresImporter.cs)	(revision 2f6400116d57c2b49f7089dbc9c8cd935c185a36)
+++ Ringtoets/Common/src/Ringtoets.Common.IO/FileImporters/StructuresImporter.cs	(.../StructuresImporter.cs)	(revision 3e3087bd9c43ca5a3910438b3c9daf0defcb09bf)
@@ -24,6 +24,7 @@
 using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
+using Core.Common.Base.Data;
 using Core.Common.Base.Geometry;
 using Core.Common.Base.IO;
 using Core.Common.IO.Exceptions;
@@ -119,23 +120,28 @@
             log.ErrorFormat(Resources.StructuresImporter_Structure_number_0_is_skipped, lineNumber);
         }
 
-        /// <summary>
-        /// Convert the variance in a <see cref="StructuresParameterRow"/> into a standard deviation.
-        /// </summary>
-        /// <param name="structureParameterRows">The <see cref="StructuresParameterRow"/> object to operate on.</param>
-        protected void ConvertVarianceToStandardDeviation(List<StructuresParameterRow> structureParameterRows)
+        protected RoundedDouble GetStandardDeviation(StructuresParameterRow structuresParameterRow)
         {
-            foreach (StructuresParameterRow row in structureParameterRows)
+            if (structuresParameterRow.VarianceType == VarianceType.CoefficientOfVariation)
             {
-                if (row.VarianceType == VarianceType.CoefficientOfVariation)
-                {
-                    log.WarnFormat(Resources.StructuresImporter_ConvertVarianceToStandardDeviation_Converting_variation_on_line_0_, row.LineNumber);
-                    row.VarianceValue = row.VarianceValue*row.NumericalValue;
-                    row.VarianceType = VarianceType.StandardDeviation;
-                }
+                log.WarnFormat(Resources.StructuresImporter_StandardDeviation_Converting_variation_on_Line_0_,
+                    structuresParameterRow.LineNumber);
+                return (RoundedDouble) structuresParameterRow.VarianceValue*Math.Abs(structuresParameterRow.NumericalValue);
             }
+            return (RoundedDouble) structuresParameterRow.VarianceValue;
         }
 
+        protected RoundedDouble GetCoefficientOfVariation(StructuresParameterRow structuresParameterRow)
+        {
+            if (structuresParameterRow.VarianceType == VarianceType.StandardDeviation)
+            {
+                log.WarnFormat(Resources.StructuresImporter_GetCoefficientOfVariation_Converting_variation_on_Line_0_,
+                    structuresParameterRow.LineNumber);
+                return (RoundedDouble) (structuresParameterRow.VarianceValue/Math.Abs(structuresParameterRow.NumericalValue));
+            }
+            return (RoundedDouble) structuresParameterRow.VarianceValue;
+        }
+
         private void CreateStructures(ReadResult<StructureLocation> importStructureLocationsResult,
                                       ReadResult<StructuresParameterRow> importStructureParameterRowsDataResult)
         {