Tom Elliott is a user on social.coop. You can follow them or interact with them if you have an account anywhere in the fediverse.
Listening to a presentation at #AIAC2018 by Javier Martínez Jiménez. He's discussing the use of water in Roman construction -- especially for structures using mortar and concrete. He's asking questions about cost for water acquisition and transport, relationships to aqueducts, quality relationships to water availability.
JMJ calculates that water needed for mortar construction is significant: you need 20-60% of final volume of mortar to get chemically correct, workable mortar. Use of mortar in case studies tracks with availability of water (e.g., functioning aqueducts).