Sure, it's not a easy way to walk to the water and clean the tunnel, it's an atmospheric pump. Common in other cultures - https://www.tandfonline.com/doi/full

Sure, it's not a easy way to walk to the water and clean the tunnel, it's an atmospheric pump. Common in other cultures - https://www.tandfonline.com/doi/full/10.1080/22797254.2018.1537684 https://www.tandfonline.com/doi/full/10.1080/22797254.2018.1... Pics of the tunnel http://people.umass.edu/proulx/online_pubs/Zurich_Puquios_revised_small.pdf http://people.umass.edu/proulx/online_pubs/Zurich_Puquios_re...