Fix manning test

core/src/callback.jl

@@ -293,7 +293,9 @@ function check_water_balance_error(u, t, integrator)::Nothing
     end
 
     if errors
-        error("Too large water balance error(s) detected.")
+        error(
+            "Too large water balance error(s) detected. Consider lowering solver tolerances or reducing shocks in the model.",
+        )
     end
     return nothing
 end

core/test/run_models_test.jl

@@ -479,21 +479,21 @@ end
 
     toml_path = normpath(@__DIR__, "../../generated_testmodels/backwater/ribasim.toml")
     @test ispath(toml_path)
-    config = Ribasim.Config(toml_path; solver_water_balance_error_reltol = Inf)
-    model = Ribasim.run(config)
+    model = Ribasim.run(toml_path)
     @test successful_retcode(model)
 
     u = model.integrator.sol.u[end]
     p = model.integrator.p
+    manning_n = first(p.manning_resistance.manning_n)
     h_actual = p.basin.current_level[parent(u)][1:50]
     x = collect(10.0:20.0:990.0)
-    h_expected = standard_step_method(x, 5.0, 1.0, 0.04, h_actual[end], 1.0e-6)
+    h_expected = standard_step_method(x, 5.0, 1.0, manning_n, h_actual[end], 1.0e-6)
 
     # We test with a somewhat arbitrary difference of 0.01 m. There are some
     # numerical choices to make in terms of what the representative friction
     # slope is. See e.g.:
     # https://www.hec.usace.army.mil/confluence/rasdocs/ras1dtechref/latest/theoretical-basis-for-one-dimensional-and-two-dimensional-hydrodynamic-calculations/1d-steady-flow-water-surface-profiles/friction-loss-evaluation
-    @test all(isapprox.(h_expected, h_actual; atol = 0.02))
+    @test all(isapprox.(h_expected, h_actual; atol = 0.04))
     # Test for conservation of mass, flow at the beginning == flow at the end
     n_self_loops = length(p.graph[].flow_dict)
     @test Ribasim.get_flow(

python/ribasim_testmodels/ribasim_testmodels/backwater.py

@@ -45,7 +45,7 @@ def backwater_model():
             [
                 manning_resistance.Static(
                     length=[20.0],
-                    manning_n=[0.04],
+                    manning_n=[0.09],
                     profile_width=[1.0],
                     profile_slope=[0.0],
                 )
@@ -69,7 +69,7 @@ def backwater_model():
 
     model.basin.add(
         Node(102, Point(1010.0, 0.0)),
-        [basin.State(level=[2.0]), basin.Profile(level=[0.0, 1.0], area=1e20)],
+        [basin.State(level=[2.0]), basin.Profile(level=[0.0, 1.0], area=1e10)],
     )
     model.edge.add(
         model.manning_resistance[101],