diff --git a/docs/en/calculators/pam/macrorugo.md b/docs/en/calculators/pam/macrorugo.md
index 09b471f1bd41e84f13579299750cae2efebeb671..0efc4e042e8ef16fd8af6bb65d5c432848fa673d 100644
--- a/docs/en/calculators/pam/macrorugo.md
+++ b/docs/en/calculators/pam/macrorugo.md
@@ -25,3 +25,8 @@ It requires the following values to be entered:
 - The width of the blocks \(D\) facing the flow (m);
 - The useful height of the blocks \(k\) (m);
 - The drag coefficient of a single block (1 for round, 2 for square).
+
+<div style="position: relative"><a id="rugosite-de-fond" style="position: absolute; top: -60px;"></a></div>
+# Bed roughness
+
+![](schema_rugosite_fond.png)
diff --git a/docs/en/calculators/pam/schema_rugosite_fond.png b/docs/en/calculators/pam/schema_rugosite_fond.png
new file mode 100644
index 0000000000000000000000000000000000000000..57969041c6d9b2d45573cd0e5a1a0bbd78d9b46a
Binary files /dev/null and b/docs/en/calculators/pam/schema_rugosite_fond.png differ
diff --git a/docs/fr/calculators/pam/macrorugo.md b/docs/fr/calculators/pam/macrorugo.md
index 646df7cff0f188f39ed5c5937258f71f7987acb7..83395baef05257c0711ed32229f849e1d8f967f9 100644
--- a/docs/fr/calculators/pam/macrorugo.md
+++ b/docs/fr/calculators/pam/macrorugo.md
@@ -26,3 +26,6 @@ Il nécessite d'entrer les valeurs suivantes&nbsp;:
 - La hauteur utile des blocs \(k\) (m)&nbsp;;
 - Le coefficient de trainée d'un bloc (1 pour rond, 2 pour carré).
 
+# Rugosité de fond
+
+![](schema_rugosite_fond.png)
diff --git a/docs/fr/calculators/pam/schema_rugosite_fond.png b/docs/fr/calculators/pam/schema_rugosite_fond.png
new file mode 100644
index 0000000000000000000000000000000000000000..ee526a871fe372484dc25a1cd18463a0de1d5c97
Binary files /dev/null and b/docs/fr/calculators/pam/schema_rugosite_fond.png differ
diff --git a/src/app/calculators/macrorugo/config.json b/src/app/calculators/macrorugo/config.json
index 6cbce4d4541d9cb123908d3026a6026c0a061954..6b9ee9a8f8c0303b91de90757d2ee8b6cc57c183 100644
--- a/src/app/calculators/macrorugo/config.json
+++ b/src/app/calculators/macrorugo/config.json
@@ -5,7 +5,10 @@
         "fields": [
             "ZF1",
             "L",
-            "Ks"
+            {
+                "id": "Ks",
+                "help": "pam/macrorugo.html#rugosite-de-fond"
+            }
         ]
     },
     {
@@ -41,4 +44,4 @@
         "type": "options",
         "help": "pam/macrorugo.html"
     }
-]
\ No newline at end of file
+]
diff --git a/src/app/calculators/macrorugocompound/config.json b/src/app/calculators/macrorugocompound/config.json
index 496a352629be9d42c5f98a37d5052df441743b16..8df7adca30b829076b1b3929bd2548686112fde9 100644
--- a/src/app/calculators/macrorugocompound/config.json
+++ b/src/app/calculators/macrorugocompound/config.json
@@ -15,7 +15,10 @@
                 "id": "If",
                 "help": "hsl/pente.html"
             },
-            "Ks",
+            {
+                "id": "Ks",
+                "help": "pam/macrorugo.html#rugosite-de-fond"
+            },
             {
                 "id": "C",
                 "help": "pam/concentration.html"
@@ -43,8 +46,14 @@
                 "type": "select",
                 "property": "inclinedApron"
             },
-            "ZRR",
-            "ZRL",
+            {
+                "id": "ZRR",
+                "help": "pam/macrorugo.html#rugosite-de-fond"
+            },
+            {
+                "id": "ZRL",
+                "help": "pam/macrorugo.html#rugosite-de-fond"
+            },
             "BR"
         ]
     },
@@ -53,7 +62,10 @@
         "type": "fieldset_template",
         "calcType": "MacroRugo",
         "fields": [
-            "ZF1",
+            {
+                "id": "ZF1",
+                "help": "pam/macrorugo.html#rugosite-de-fond"
+            },
             "B"
         ]
     },
@@ -69,4 +81,4 @@
         "selectIds": [ "select_passtype" ],
         "help": "pam/macrorugo_complexe.html"
     }
-]
\ No newline at end of file
+]