Prague is the capital and largest city in the Czech Republic, the 13th largest city in the European Union and the historical capital of Bohemia. Situated on the Vltava river, Prague is home to about 1.3 million people, while its metropolitan area is estimated to have a population of 2.7 million. The public water system in Prague and the drinking water treatment plants have been administered by the joint stock company of prazska vodohospodarska spolecnost, a. s. since 1998. The joint stock company of Prazske vodovody a kanalizace, a. s. (PVK) is the operator of the water distribution system.
The Prague water system is comprised of 3549 Km of pipelines and serves 1.3 million customers through 116,500 service connections. A total of 91.2 million cubic meters of water were delivered in 2021 with non-revenue water (NRW) levels at 12.7 million cubic meters, or 14.1%. PVK has been doing an excellent job of reducing NRW from over 40% in the late 1990’s to a low of 12.9% in 2020. 2021 saw a rise in NRW to 2016 levels and PVK saw a need to perform pro-active leak detection work.
A pilot study using the ASTERRA satellite leak detection pre-location service was performed in 2020 with good results. PVK then entered into a 3-year service agreement to survey 1000 Km of pipeline per year. The first service was performed in March 2021. This service resulted in the finding of 126 leaks within 109.9 Km of pipeline that was physically inspected by field leak crews in a total of 41 working days. Thus 3.1 leaks were found per day and 1.1 leaks were found per kilometer within the likely leak locations identified by ASTERRA. Of those 126 leaks, 73 were surfacing leaks and reported via work orders by the public. The other 53 leaks were non-surfacing leaks that were found by the field inspectors. Non-surfacing leaks contribute the most to recalcitrant system water losses as they can remain undetected for months or years. The 53 leaks accounted for 417,850 cubic meters of water volume per year that was saved. This water recovery reduced the NRW from 14.1% to 13.7% in this one service and saved PVK €160,100 per year based on a cost of water production of €0.38 per cubic meter.