Oh wow! I never expected these types of projects to be this complex! The treatment plant design and the urban distribution network sound pretty challenging as these are the 2 points you've mentioned that require the expertise and professional experience of a skilled hydraulic engineer. Many thanks also for connecting with Engr. Calogero Brutto, the original hydraulic engineer (who also involved the valuable contribution of Engr. Manuel Vicente Mendez) for shedding light on the design and construction of the treatment plant. Thank you @manuelmilano for showing us your interesting explorations of this marvel of engineering! Cheers!