diff --git a/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.cpp b/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.cpp
index cb7494151c2f9fd83c4dafc70cf529415ab68ab5..03f4229158df7866cfa3cdb7c6f56efa9bdf7f99 100644
--- a/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.cpp
+++ b/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.cpp
@@ -23,8 +23,8 @@ void PermeabilityModel<DisplacementDim>::eval(
     CapillaryPressureData<DisplacementDim> const& p_cap_data,
     TemperatureData<DisplacementDim> const& T_data,
     PorosityData const& poro_data, LiquidViscosityData const& mu_L_data,
-    PorosityData& transport_poro_data,
-    PorosityData const& transport_poro_data_prev,
+    TransportPorosityData& transport_poro_data,
+    TransportPorosityData const& transport_poro_data_prev,
     SolidMechanicsDataStateless<DisplacementDim> const& s_mech_data,
     StrainData<DisplacementDim> const& eps_data,
     StrainData<DisplacementDim> const& eps_prev_data,
diff --git a/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.h b/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.h
index e3a252b373d9d19a731bb92623ed1928454253fd..ae3eb3c5b52e33337595fdd38498e81b5781b94b 100644
--- a/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.h
+++ b/ProcessLib/ThermoRichardsMechanics/Constitutive/Permeability.h
@@ -36,8 +36,8 @@ struct PermeabilityModel
               PorosityData const& poro_data,
               LiquidViscosityData const& mu_L_data,
               // TODO evaluate transport porosity evolution separately
-              PorosityData& transport_poro_data,
-              PorosityData const& transport_poro_data_prev,
+              TransportPorosityData& transport_poro_data,
+              TransportPorosityData const& transport_poro_data_prev,
               SolidMechanicsDataStateless<DisplacementDim> const& s_mech_data,
               StrainData<DisplacementDim> const& eps_data,
               StrainData<DisplacementDim> const& eps_prev_data,
diff --git a/ProcessLib/ThermoRichardsMechanics/Constitutive/Porosity.h b/ProcessLib/ThermoRichardsMechanics/Constitutive/Porosity.h
index 42dfa5c813fab638336cb292d44b539295082605..22af0a1ccba8f68a371bb5c93dc31a8f26af37b1 100644
--- a/ProcessLib/ThermoRichardsMechanics/Constitutive/Porosity.h
+++ b/ProcessLib/ThermoRichardsMechanics/Constitutive/Porosity.h
@@ -22,6 +22,17 @@ struct PorosityData
     double phi;
 };
 
+struct TransportPorosityData
+{
+    double phi;
+
+    static auto reflect()
+    {
+        return std::make_tuple(
+            ReflectionData{"transport_porosity", &TransportPorosityData::phi});
+    }
+};
+
 template <int DisplacementDim>
 struct PorosityModel
 {
diff --git a/ProcessLib/ThermoRichardsMechanics/ConstitutiveSetting.h b/ProcessLib/ThermoRichardsMechanics/ConstitutiveSetting.h
index 77307c26c2863431794cd491d85799d5e80d463e..3148811324fb5d795fab9989285210dfb7f2e848 100644
--- a/ProcessLib/ThermoRichardsMechanics/ConstitutiveSetting.h
+++ b/ProcessLib/ThermoRichardsMechanics/ConstitutiveSetting.h
@@ -36,7 +36,7 @@ struct StatefulData
 {
     SaturationData S_L_data;
     PorosityData poro_data;
-    PorosityData transport_poro_data;
+    TransportPorosityData transport_poro_data;
     StrainData<DisplacementDim> eps_data;
     SwellingDataStateful<DisplacementDim> swelling_data;
     SolidMechanicsDataStateful<DisplacementDim> s_mech_data;