Water supply and distribution

The third part of the drinking water triptych, distribution is the only part of the process that is perceptible to the user, from the meter onwards. It's also the part that seems both the simplest (bits of pipe) and the darkest (underground network). It's also the part that seems to have evolved little: and yet, how far we've come since the Roman aqueducts, the first wooden pipes and the pendulum wells or norias to raise the water! Ductile cast iron, bi-oriented PVCs, polyethylenes, composite pipes (cement core sheet metal, GRP, etc.) and internal and external coatings provide a high level of durability and sanitary safety. These materials and installation techniques have evolved towards low-cost, low-disturbance operations (sinking, directional drilling, in situ replacement, etc.).

Leak-tight networks are a constant quest for good managers, both to reduce the customer's bill, who has no desire to pay for leaks (well-managed urban networks can boast efficiencies of 90%), and to maintain a high level of sanitary safety for the consumer; today's resources enable rapid, accurate detection on all materials and in all environments. Network management, increasingly centralized and computerized, relies on equipment and control systems based on both traditional principles and cutting-edge technologies. Finally, water metering ensures that charges are fairly distributed among users, and today's meters are highly accurate, detecting and recording flows in the order of liters per minute.

Over the last few decades, pumping techniques have not evolved spectacularly, but motor efficiencies have improved, variable speed drives have been perfected, and seals are better and more durable. It should be noted that in this article, we will be dealing with conveyors in general, and with the notions of free-surface and loaded flow, which are well integrated with the notion of networks and pipelines. A final nod to the dawn of the third millennium: computers have logically made their entry into this very down-to-earth field, and yet the technician still uses tables and abacuses for many a quick estimate.