From 8fd8f9c04492cce60c1cd1e6b9a53057990ec31e Mon Sep 17 00:00:00 2001
From: Elisabeth Lutz <168072575+Lutzeli@users.noreply.github.com>
Date: Thu, 5 Feb 2026 13:38:13 +0100
Subject: Add unit check for rate and set units for PEC calculation

without this change PEC units will apear as [g/ha] when the rate input is given in [g/ha]
---
 R/PEC_sw_drainage_UK.R | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/R/PEC_sw_drainage_UK.R b/R/PEC_sw_drainage_UK.R
index 4b3111e..2c7e28f 100644
--- a/R/PEC_sw_drainage_UK.R
+++ b/R/PEC_sw_drainage_UK.R
@@ -33,7 +33,8 @@ PEC_sw_drainage_UK <- function(rate, interception = 0, Koc,
                                    model = NULL, model_parms = NULL)
 {
   percentage_lost <- SSLRC_mobility_classification(Koc)[[2]]
-  amount_available <- rate * (1 - interception) # g/ha
+  if (inherits(rate, "units") && !identical(as.character(units(rate)), "g/ha")) stop("rate must have units g/ha, not ", units(rate))
+  amount_available <- as.numeric(rate) * (1 - interception) # g/ha
 
   if (!missing(latest_application)) {
     lct <- Sys.getlocale("LC_TIME")
@@ -62,6 +63,6 @@ PEC_sw_drainage_UK <- function(rate, interception = 0, Koc,
   } 
 
   volume = 130000 # L/ha
-  PEC = 1e6 * (percentage_lost/100) * amount_available / volume
+  PEC = set_units(1e6 * (percentage_lost/100) * amount_available / volume, "µg/L")
   return(PEC)
 }
-- 
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