E3SM-Project · mabrunke · May 16, 2025 · Jul 24, 2025 · Aug 1, 2025 · Nov 4, 2025
diff --git a/components/elm/bld/namelist_files/namelist_defaults.xml b/components/elm/bld/namelist_files/namelist_defaults.xml
@@ -113,6 +113,9 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
 <!-- Do variable soil thickness -->
 <use_var_soil_thick>.false.</use_var_soil_thick>
 
+<!-- Use h3D -->
+<use_h3d>.false.</use_h3d>
+
 <!-- Do downscaling to topounit -->
 <precip_downscaling_method>ERMM</precip_downscaling_method>
 <!-- Do lake water storage -->

diff --git a/components/elm/bld/namelist_files/namelist_definition.xml b/components/elm/bld/namelist_files/namelist_definition.xml
@@ -2054,6 +2054,11 @@ Runtime flag to turn on/off PETSc based thermal model.
 Runtime flag to turn on/off variable soil thickness.
 </entry>
 
+<entry id="use_h3d" type="logical" category="default_settings"
+	group="elm_inparm" valid_values="">
+Runtime flag to turn on/off h3D.
+</entry>
+
 <!-- ======================================================================================== -->
 <!-- Namelist options for lake water storage                                                  -->
 <!-- ======================================================================================== -->

diff --git a/components/elm/docs/figures/h3d_schematic.jpg b/components/elm/docs/figures/h3d_schematic.jpg