The flow came exactly from here : https://www.mapillary.com/app/?pKey=475822118363098 but as reedbed is feed  by the spring it should be more to the north (i see a cavity in lidar but that's dont prove the precise spring position). The wetland is on fenced private propriety and i don't have seen habitants. I will return one of nexts week-ends when the farm has is market open to ask them if they have more information.