--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/services/DynamicMainValuesService.java	Fri Sep 21 18:19:41 2018 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/services/DynamicMainValuesService.java	Mon Sep 24 18:01:10 2018 +0200
@@ -61,12 +61,14 @@
             throws MainValuesServiceException {
 
         // Query the gauge's daily Q values
-        final List<DailyDischargeValue> qdvs = DailyDischargeValue.getValues(gauge, startTime, endTime, OrderByField.DAY);
+        final Date qStartTime = DateUtils.getAbflussYear(startTime)[0];
+        final List<DailyDischargeValue> qdvs = DailyDischargeValue.getValues(gauge, qStartTime, endTime, OrderByField.DAY);
         if (qdvs.isEmpty())
             throw new MainValuesServiceException("no daily discharge values for gauge " + gauge.getName() + " in the requested time period");
         // return;
 
         // Build yearly aggregates
+        final Date qYearEnd = DateUtils.getPreviousAbflussYear(endTime)[1];
         final TDoubleArrayList mnqs = new TDoubleArrayList();
         final TDoubleArrayList mqs = new TDoubleArrayList();
         int mqcnt = 0;
@@ -87,6 +89,8 @@
                     mqs.set(j, mqs.get(j) / mqcnt);
                     j++;
                 }
+                if (qdv.getDay().after(qYearEnd))
+                    break;
                 // Start next year
                 mnqs.add(qdv.getDischarge().doubleValue());
                 mhqs.add(qdv.getDischarge().doubleValue());
@@ -115,10 +119,12 @@
         if (hsq2 != null)
             mainValues.add(hsq2);
 
-        // Query the gauge's daily Q values and build a list sorted by ascending Q
+        // Query the gauge's daily Q values from the first new year on, and build a list sorted by ascending Q
         final TDoubleArrayList qs = new TDoubleArrayList();
-        for (final DailyDischargeValue qdv : qdvs)
-            qs.add(qdv.getDischarge().doubleValue());
+        for (final DailyDischargeValue qdv : qdvs) {
+            if (qdv.getDay().compareTo(startTime) >= 0)
+                qs.add(qdv.getDischarge().doubleValue());
+        }
         qs.sort();
 
         // Step through the sorted Q list and get the duration discharges
@@ -137,14 +143,22 @@
     }
 
     /**
-     * Checks year equality of two dates (calendar year)
+     * Checks year equality of two dates (Abflussjahr)
      */
     private boolean isSameQYear(final Date a, final Date b) {
-        final Calendar ca = Calendar.getInstance();
-        ca.setTime(a);
-        final Calendar cb = Calendar.getInstance();
-        cb.setTime(b);
-        return (ca.get(Calendar.YEAR) == cb.get(Calendar.YEAR));
+        return (qYear(a) == qYear(b));
+    }
+
+    /**
+     * Gets the q year (Abflussjahr) of a date
+     */
+    private int qYear(final Date day) {
+        final Calendar cal = Calendar.getInstance();
+        cal.setTime(day);
+        if (cal.get(Calendar.MONTH) >= 10)
+            return cal.get(Calendar.YEAR) + 1;
+        else
+            return cal.get(Calendar.YEAR);
     }
 
     /**

--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/services/DynamicMainValuesTimeRangeDeterminationService.java	Fri Sep 21 18:19:41 2018 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/services/DynamicMainValuesTimeRangeDeterminationService.java	Mon Sep 24 18:01:10 2018 +0200
@@ -60,6 +60,10 @@
         private static class GaugeInfo {
             protected final String errorMsg;
             protected final Gauge gauge;
+            /**
+             * New year of the first year for which the gauge has complete discharge data, including november+december of the year
+             * before
+             */
             protected final Date startdate;
             protected final Date enddate;
 
@@ -83,12 +87,13 @@
         // Query the gauge's daily Q values
         String globalErrorMsg = "";
         final List<GaugeInfoResult.GaugeInfo> gaugeResults = new ArrayList<>();
-        Date min = startTime;
+        final Date qStartTime = DateUtils.getAbflussYear(startTime)[0];
+        Date min = qStartTime;
         Date max = endTime;
 
         for (final Gauge gauge : gauges) {
 
-            final Date[] gaugeDates = DailyDischargeValue.getTimePeriod(gauge, startTime, endTime);
+            final Date[] gaugeDates = DailyDischargeValue.getTimePeriod(gauge, qStartTime, endTime);
             if (gaugeDates[0] == null) {
                 final String msg = Resources.getMsg(meta, "bundu.wst_no_data_at_all", "bundu.wst_no_data_at_all", gauge.getName());
                 final GaugeInfoResult.GaugeInfo gi = new GaugeInfoResult.GaugeInfo(msg, gauge, null, null);
@@ -98,24 +103,26 @@
                 continue;
             }
 
+            final Date gaugeCalcStartDate = DateUtils.getNextAbflussYear(gaugeDates[0])[0];
             if (gaugeDates[0].getTime() > min.getTime())
-                min = gaugeDates[0];
+                min = gaugeCalcStartDate;
 
             if (gaugeDates[1].getTime() < max.getTime())
                 max = gaugeDates[1];
 
             String errormsg = null;
-            if ((gaugeDates[1].getTime() < endTime.getTime()) || (gaugeDates[0].getTime() > startTime.getTime()))
-                errormsg = makeDoesNotCoverErrorMsg(gaugeDates[0], gaugeDates[1], meta);
+            if ((gaugeDates[1].getTime() < endTime.getTime()) || (gaugeDates[0].getTime() > qStartTime.getTime()))
+                errormsg = makeDoesNotCoverErrorMsg(DateUtils.getAbflussYearFromDate(gaugeCalcStartDate), DateUtils.getYearFromDate(gaugeDates[1]), meta);
 
-            gaugeResults.add(new GaugeInfoResult.GaugeInfo(errormsg, gauge, gaugeDates[0], gaugeDates[1]));
+            gaugeResults.add(new GaugeInfoResult.GaugeInfo(errormsg, gauge, DateUtils.getNextNewYear(gaugeCalcStartDate), gaugeDates[1]));
         }
 
         // common Range and correct errorMsg
+        min = DateUtils.getNextNewYear(min);
         final List<GaugeInfoResult.GaugeInfo> gaugeResultsSecondTurn = new ArrayList<>();
         for (final GaugeInfoResult.GaugeInfo gi : gaugeResults) {
             gaugeResultsSecondTurn
-                    .add(new GaugeInfoResult.GaugeInfo(gi.errorMsg, gi.gauge, gi.startdate != null ? min : null, gi.enddate != null ? max : null));
+            .add(new GaugeInfoResult.GaugeInfo(gi.errorMsg, gi.gauge, gi.startdate != null ? min : null, gi.enddate != null ? max : null));
         }
         if (globalErrorMsg.isEmpty() && (min.getTime() > max.getTime()))
             globalErrorMsg = getMsg(meta, "bundu.wst.gauge_timeranges_disjoint");
@@ -130,9 +137,9 @@
         return result;
     }
 
-    private String makeDoesNotCoverErrorMsg(final Date start, final Date end, final CallMeta meta) {
+    private String makeDoesNotCoverErrorMsg(final int startYear, final int endYear, final CallMeta meta) {
         final String msgkey = "bundu.wst.range_does_not_cover";
-        return Resources.getMsg(meta, msgkey, msgkey, DateUtils.getYearFromDate(start), DateUtils.getYearFromDate(end));
+        return Resources.getMsg(meta, msgkey, msgkey, startYear, endYear);
     }
 
     @Override