diff --git a/R/CreateInputsModel.R b/R/CreateInputsModel.R
index d09031ca95dc9833571fe46cb383673f10b816a8..2a2a6488620aaacdc33a124b7e4756064e2ce79f 100644
--- a/R/CreateInputsModel.R
+++ b/R/CreateInputsModel.R
@@ -212,6 +212,9 @@ CreateInputsModel <- function(FUN_MOD,
     if(any(is.na(Qupstream))) {
       stop("'Qupstream' cannot contain any NA value")
     }
+    if(any(LengthHydro > 1000)) {
+      warning("The unit of 'LengthHydro' has changed from m to km in v1.7 of airGR: values superior to 1000 km seem unrealistic")
+    }
   }
 
   ##check_NA_values