--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/sinfo/flowdepth/FlowDepthUtils.java	Tue Mar 13 18:49:33 2018 +0100
@@ -0,0 +1,61 @@
+/** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde
+ * Software engineering by
+ *  Björnsen Beratende Ingenieure GmbH
+ *  Dr. Schumacher Ingenieurbüro für Wasser und Umwelt
+ *
+ * This file is Free Software under the GNU AGPL (>=v3)
+ * and comes with ABSOLUTELY NO WARRANTY! Check out the
+ * documentation coming with Dive4Elements River for details.
+ */
+package org.dive4elements.river.artifacts.sinfo.flowdepth;
+
+import org.dive4elements.river.artifacts.model.Calculation;
+import org.dive4elements.river.artifacts.states.WaterlevelData;
+
+/**
+ * @author Gernot Belger
+ */
+public final class FlowDepthUtils {
+
+    private FlowDepthUtils() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Checks the year difference between waterlevels and sounding, and issues a warning if too big.
+     *
+     * Zeitraum Zeitliche Differenz [a]
+     * X ≥ 1998 ± 3
+     * 1958 ≤ X < 1998 ± 6
+     * 1918 ≤ X < 1958 ± 12
+     * X < 1918 ± 25
+     */
+    public static void checkYearDifference(final String label, final WaterlevelData waterlevel, final int soundingYear, final Calculation problems) {
+
+        final int wstYear = waterlevel.getYear();
+        if (wstYear < 0)
+            return;
+
+        final int maxDifference = getMaxDifferenceYears(soundingYear);
+
+        final int difference = Math.abs(soundingYear - wstYear);
+        if (difference > maxDifference) {
+            problems.addProblem("sinfo_calc_flow_depth.warning.year_difference", label, wstYear, soundingYear);
+        }
+    }
+
+    public static int getMaxDifferenceYears(final int year) {
+
+        if (year < 1918)
+            return 25;
+
+        if (1918 <= year && year < 1958)
+            return 12;
+
+        if (1958 <= year && year < 1998)
+            return 6;
+
+        /* >= 1998 */
+        return 3;
+    }
+}
\ No newline at end of file