diff --git a/README.md b/README.md
index dfcdb8f0aa983353e8dae457a087b050ff4c645d..7dd6bc8cf08094cfc8467d471ca0b8cc72505542 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,8 @@
 Christine Poulard, Céline Berni, INRAE  June 2021
 
 Teaching tool to illustrate the influence of the rugosity and computation space-step on the estimation of a simple backwater curve, in a Wide rectangular channel.
-One script is interactive, with sliders ; the other not, to be easier to understand
+
+The simplest script is ligne-eau-reservoir_vuCP, in french only.
+For demo purposes "subcritical_flow_channel_into_reservoir.py" was developped : it is interactive, with sliders allowing to modify the values of roughness and discretisation step.
+
+![screenshot](https://gitlab.irstea.fr/hydrotools_demosandprocessing/backwater-curve-approximation/-/blob/master/screenshots/Subcritical_backwater.PNG)