diff --git a/Ausgleichsbecken.py b/Ausgleichsbecken.py
index e69de29..f56b829 100644
--- a/Ausgleichsbecken.py
+++ b/Ausgleichsbecken.py
@@ -0,0 +1,35 @@
+import numpy as np 
+
+def Volume_trend(influx,outflux,timestep=1,V_0=0):
+    '''
+    Returns the trend and the volume and the final volume, defined
+    by influx and outflux patterns. The optional parameter timestep
+    defines the time increment over which the fluxes are changing.
+    '''
+    net_flux = influx-outflux
+    delta_V = net_flux*timestep
+    V_trend = V_0+np.cumsum(delta_V)
+    V_end = V_trend[-1]
+    return V_end, V_trend
+
+def Height_trend(V_trend,area=1,h_crit_low=-np.inf,h_crit_high=np.inf):
+    '''
+    Returns the trend and the height and the final height, defined
+    by influx and outflux patterns as well as the crosssection area.
+    The optional parameters h_crit_low/high indicate limits that the height
+    should never exceed. If this occures, TRUE is returned in the corresponding
+    h_crit_flag.
+    '''
+    h_trend = V_trend/area
+    h_crit_flag_low = np.any(h_trend <= h_crit_low)
+    h_crit_flag_high = np.any(h_trend >= h_crit_high)
+    h_end = h_trend[-1]
+    return h_trend,h_end,h_crit_flag_low,h_crit_flag_high
+
+## testing
+if __name__ == "__main__":
+    influx = np.full([1,100], 6)
+    outflux = np.full_like(influx, 4)
+    V_end, V_trend = Volume_trend(influx, outflux,timestep=0.5,V_0 = 100)
+    print(V_end)
+    print(V_trend)