--- 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);
     }
 
     /**