Add stage--depth offset for Q-->h.

ottar/ottar.py

@@ -83,13 +83,14 @@ def dynamic_time_step(self, max_fract_to_equilib=0.1):
         # Currently part of a big, messy "update" step
         pass
 
-    def initialize_flow_calculations(self, channel_n, fp_k, fp_P, use_Rh ):
+    def initialize_flow_calculations(self, channel_n, fp_k, fp_P,
+                                            stage_offset, use_Rh ):
         """
         Hard-code for double Manning
         """
         self.channel_n = channel_n
         self.hclass = FlowDepthDoubleManning(use_Rh)
-        self.hclass.initialize( channel_n, fp_k, fp_P,
+        self.hclass.initialize( channel_n, fp_k, fp_P, stage_offset,
                                 self.h_banks, self.b[-1], self.S)
 
 
@@ -796,6 +797,9 @@ def set_k(self, _var):
 
     def set_P(self, _var):
         self.P = _var
+
+    def set_stage_offset(self, _var):
+        self.stage_offset = _var
 
     def set_h_bank(self, _var):
         self.h_bank = _var
@@ -809,7 +813,9 @@ def set_S(self, _var):
     def set_Q(self, _var):
         self.Q = _var
 
-    def flow_depth_from_Manning_discharge( self, h ):
+    def flow_depth_from_Manning_discharge( self, stage ):
+        # flow depth
+        h = stage - self.stage_offset
         # Does the flow go overbank?
         ob = h > self.h_bank
         if self.use_Rh:
@@ -827,10 +833,11 @@ def compute_depth(self, Q=None):
         else:
             return fsolve( self.flow_depth_from_Manning_discharge, 1. )[0]
 
-    def initialize(self, n, k, P, h_bank, b, S):
+    def initialize(self, n, k, P, stage_offset, h_bank, b, S):
         self.set_n(n)
         self.set_k(k)
         self.set_P(P)
+        self.set_stage_offset(stage_offset)
         self.set_h_bank(h_bank)
         self.set_b(b)
         self.set_S(S)