--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/model/Calculation2.java	Wed Jun 26 13:26:43 2013 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/model/Calculation2.java	Wed Jun 26 13:33:15 2013 +0200
@@ -8,6 +8,9 @@
 
 package org.dive4elements.river.artifacts.model;
 
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
 import java.util.Arrays;
 
 import org.apache.log4j.Logger;
@@ -28,12 +31,57 @@
         this.km = km;
     }
 
+    private void dump(double [][] wqs) {
+        double [] ws = wqs[0];
+        double [] qs = wqs[1];
+
+        String filename = "/tmp/computed-discharge-curve-" + km + "-" +
+            System.currentTimeMillis() + ".txt";
+
+        PrintWriter pw = null;
+        try {
+            pw =
+                new PrintWriter(
+                new FileWriter(filename));
+
+            for (int i = 0; i < ws.length; ++i) {
+                pw.println(ws[i] + " " + qs[i]);
+            }
+
+            pw.flush();
+        }
+        catch (IOException ioe) {
+            logger.error(ioe);
+        }
+        finally {
+            if (pw != null) {
+                pw.close();
+            }
+        }
+    }
+
     public CalculationResult calculate(WstValueTable wst) {
 
-        logger.debug("Calculation2.calculate");
+        boolean debug = logger.isDebugEnabled();
+
+        if (debug) {
+            logger.debug("Calculation2.calculate: km " + km);
+        }
 
         double [][] wqs = wst.interpolateWQ(km, this);
 
+        if (debug) {
+            if (hasProblems()) {
+                logger.debug("problems: " + problemsToString());
+            }
+            logger.debug("wqs: " + wqs);
+            if (wqs != null && wqs[0] != null) {
+                logger.debug("wqs length: " + wqs[0].length);
+                // TODO: Uncomment to see the data externally.
+                //dump(wqs);
+            }
+        }
+
         if (wqs == null || wqs[0].length == 0) {
             addProblem("cannot.compute.discharge.curve");
             return new CalculationResult(new WQKms[0], this);