diff --git a/docs/en/calculators/hsl/cote_amont_aval.md b/docs/en/calculators/hsl/cote_amont_aval.md
new file mode 100644
index 0000000000000000000000000000000000000000..98d6429018f849e4c3d1632a4e312e1cbbd98d74
--- /dev/null
+++ b/docs/en/calculators/hsl/cote_amont_aval.md
@@ -0,0 +1,11 @@
+# Upstream / downstream elevations of a reach
+
+This module is based on the equations of the [backwater curves module](courbe_remous.md) and is used to calculate the following:
+
+- The water elevation upstream of a reach of a fluvial backwater curve;
+- The water elevation downstream of a reach of a torrential backwater curve;
+- The flow that connects the upstream and downstream water elevations of a fluvial or torrential backwater curve.
+
+The regime chosen on the type of water line determines whether the calculation is made from downstream to upstream (fluvial regime) and from upstream to downstream (torrential regime).
+
+This calculation module is particularly useful for calculating the water line of a series of hydraulic structures or reaches (see the typical example "Flow of a channel with structures").
diff --git a/docs/fr/calculators/hsl/cote_amont_aval.md b/docs/fr/calculators/hsl/cote_amont_aval.md
new file mode 100644
index 0000000000000000000000000000000000000000..a3f27e286d49e694b45139f54f88e460e5de3b0b
--- /dev/null
+++ b/docs/fr/calculators/hsl/cote_amont_aval.md
@@ -0,0 +1,12 @@
+# Cotes amont / aval d'un bief
+
+Ce module basé sur les équations du [module de calcul des courbes de remous](courbe_remous.md) permet de calculer :
+
+- La cote de l'eau à l'amont d'un bief d'une courbe de remous fluviale 
+- La cote de l'eau à l'aval d'un bief d'une courbe de remous torrentielle 
+- Le débit permettant de relié les cotes de l'eau amont et aval d'une courbe de remous fluviale ou torrentielle.
+
+Le régime choisi sur le type de ligne d'eau détermine si le calcul s'effectue de l'aval vers l'amont (régime fluvial) et de l'amont vers l'aval (régime torrentiel).
+
+Ce module de calcul est particulièrement utile pour calculer la ligne d'eau d'un enchaînement de ouvrages hydrauliques ou de biefs (Voir l'exemple type "Débit d'un chenal avec ouvrages").
+
diff --git a/mkdocs-en.yml b/mkdocs-en.yml
index 409dc0282939bf2ee17cacef9f87152464b97532..fc9fc321d57aafa3eb1600956bd9429846e3f524 100644
--- a/mkdocs-en.yml
+++ b/mkdocs-en.yml
@@ -32,6 +32,7 @@ nav:
     - Open-channel flow:
         - Uniform flow: calculators/hsl/regime_uniforme.md
         - calculators/hsl/courbe_remous.md
+        - calculators/hsl/cote_amont_aval.md
         - calculators/hsl/section_parametree.md
         - calculators/hsl/pente.md
         - calculators/hsl/types_sections.md
diff --git a/mkdocs-fr.yml b/mkdocs-fr.yml
index 947cffb0553da3cffcdbae51e106aa2318b8873d..e32b6f3f81073700ee9eb541958f1c32d6b9d2cf 100644
--- a/mkdocs-fr.yml
+++ b/mkdocs-fr.yml
@@ -32,6 +32,7 @@ nav:
     - Hydraulique à surface libre:
         - Régime uniforme: calculators/hsl/regime_uniforme.md
         - calculators/hsl/courbe_remous.md
+        - calculators/hsl/cote_amont_aval.md
         - calculators/hsl/section_parametree.md
         - calculators/hsl/pente.md
         - calculators/hsl/types_sections.md
diff --git a/src/app/calculators/bief/config.json b/src/app/calculators/bief/config.json
index 399d8a25fea8439439f61dbdcc2e914864e37556..95f2ca549d1b5dc05e6a6b4a750015c93ceca321 100644
--- a/src/app/calculators/bief/config.json
+++ b/src/app/calculators/bief/config.json
@@ -70,6 +70,6 @@
         "type": "options",
         "defaultNodeType": "SectionRectangle",
         "selectIds": [ "select_section", "select_regime" ],
-        "help": "hsl/bief.html"
+        "help": "hsl/cote_amont_aval.html"
     }
 ]
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