diff --git a/src/structure/structure.ts b/src/structure/structure.ts
index fcd0e5e12eeee7e89de207c6bd55614f3735aabf..c3effee93fa0176b5226db684b896cba39fd5cfb 100644
--- a/src/structure/structure.ts
+++ b/src/structure/structure.ts
@@ -33,6 +33,18 @@ export enum StructureFlowRegime {
     NULL,
 }
 
+/**
+ * Type de jet : Sans objet (orifice), plongeant, de surface
+ */
+export enum StructureJetType {
+    /** Sans objet (orifice) */
+    SO,
+    /** Plongeant */
+    PLONGEANT,
+    /** De surface */
+    SURFACE,
+}
+
 /**
  * classe de calcul sur la conduite distributrice
  */
@@ -212,4 +224,22 @@ export abstract class Structure extends Nub {
             return StructureFlowRegime.SUBMERGED;
         }
     }
+
+    /**
+     * Give the Jet Type for weir flow
+     * Cf. Baudoin J.M., Burgun V., Chanseau M., Larinier M., Ovidio M., SremskiW., Steinbach P. et Voegtle B., 2014.
+     * Evaluer le franchissement des obstacles par les poissons. Principes et méthodes. Onema. 200 pages
+     */
+    protected getJetType(): StructureJetType {
+        if (this.getFlowMode() === StructureFlowMode.WEIR) {
+            if (Math.abs(this.prms.h1.v - this.prms.h2.v) < 0.5 * this.prms.h1.v) {
+                return StructureJetType.SURFACE;
+            } else {
+                return StructureJetType.PLONGEANT;
+            }
+        } else {
+            return StructureJetType.SO;
+        }
+    }
+
 }
diff --git a/src/structure/structure_params.ts b/src/structure/structure_params.ts
index 28ff720ad5f5dd5b8cd186ddbaf304f566ff9bd7..8740525ea3d4334f39b65c0c2c7f3f0ca25f8edf 100644
--- a/src/structure/structure_params.ts
+++ b/src/structure/structure_params.ts
@@ -1,7 +1,7 @@
 import { Nub } from "../nub";
-import { ParamsEquation } from "../param/params-equation";
 import { ParamDefinition } from "../param/param-definition";
 import { ParamDomainValue } from "../param/param-domain";
+import { ParamsEquation } from "../param/params-equation";
 
 /**
  * Common parameters of hydraulic structure equations