diff --git a/python/ngen_conf/src/ngen/config/topmod.py b/python/ngen_conf/src/ngen/config/topmod.py
index ab0a316f..8d09f7c6 100644
--- a/python/ngen_conf/src/ngen/config/topmod.py
+++ b/python/ngen_conf/src/ngen/config/topmod.py
@@ -5,14 +5,44 @@
 
 from .bmi_formulation import BMIC
 
+
 class TopmodParams(BaseModel):
-    """Class for validating Topmod Parameters
+    """Class for validating Topmod Parameters"""
+    szm: Optional[float]
+    """
+    Exponential scaling parameter for decline of transmissivity with increase in storage deficit
+    Unit: meters (m)
     """
     sr0: Optional[float]
+    """
+    initial root zone storage deficit
+    Unit: meters (m)
+    """
     srmax: Optional[float]
-    szm: Optional[float]
-    t0: Optional[float]
+    """
+    Maximum capacity of the root zone  (Available water capacity to plants)
+    Unit: meters (m)
+    """
     td: Optional[float]
+    """
+    Time delay for recharge to the saturated zone per unit of deficit
+    Unit: hours (h)
+    """
+    t0: Optional[float]
+    """
+    natural log of downslope transmissivity when the soil is just saturated to the surface (corresponds to transmissivities of 0.000335 and 2980.96 m/h)
+    Unit: meters per hour (m/h)
+    """
+    chv: Optional[float]
+    """
+    Average channel flow velocity
+    Unit: meters per hour (m/h)
+    """
+    rv: Optional[float]
+    """
+    Internal overland flow routing velocity
+    Unit: meters per hour (m/h)
+    """
 
 class Topmod(BMIC):
     """A BMIC implementation for the Topmod ngen module