A record-breaking water supply in Riga: 'We rely on the reliability of others'

The water supply system in Rijeka, Slovenia, is currently operating without interruption despite record consumption levels driven by high temperatures and the peak tourist season. According to director Pregelj of the Rijeka Waterworks, the situation highlights an extraordinary drought and unprecedented demand for drinking water. Users consume up to 37,000 cubic meters of water per day, which would fill 15 Olympic-sized swimming pools. The average current consumption stands at 430 liters per second. Domestic sources within the company cover only about a third of all needs, providing approximately 115 to 150 liters of water per second. “The situation on site confirms our dependence, since the River Rijana practically dries up and we get nothing more from its source. We carry the name of the river, but during summer we become less and less the Rijeka Waterworks,” Pregelj emphasized. Currently, the majority of the water supplied comes from neighboring networks. “We remain stable mainly on foreign accounts,” Pregelj explained. The Tržaški Waterworks contributes ten liters per second, the Kraški Waterworks 100 liters, and the Istrian Waterworks and Drainage from Buzet another 150 liters per second. “Our network literally ‘slips’ on the reliability of others, since we fall immediately when something stalls with neighbors,” he added. Fortunately, neighboring companies have successfully upgraded their infrastructure over recent years. In the Croatian Istria, they have timely filled their own accumulations. This timely neighborly help has thus far successfully prevented complete reductions and shortages in households. Despite these efforts, the Rijeka Waterworks strongly urges residents to conserve water for non-essential tasks such as lawn watering or car washing. “We sell water like a merchant, but at the same time we ask customers to use it as little as possible,” Pregelj described with irony. The company is intensively searching for long-term solutions to summer droughts and regularly cleans pipes. Each year, the entire amount of collected funds from the network is invested in network renewal. The network alone in Slovenian Istria measures 1,000 kilometers. “Our water losses currently represent an acceptable share compared to other waterworks in the country, although worn-out pipes continuously leak and require regular repairs,” Pregelj added. Experts in seeking funds for further renewals and new water connections heavily rely primarily on European cohesion funds. The leadership sees the only real solution solely in reservoirs and large accumulations. Director Pregelj completely excluded seawater desalination. Returning concentrated brine could, according to his warnings, destroy the enclosed ecosystem of the Tržaško Bay. Therefore, the leadership sees the only real solution solely in reservoirs and large accumulations. Engineers are currently analyzing five potential locations along the Istria. One of the very serious options foresees the construction of a large accumulation in the quarry Griža near Rijeka. Miners will soon finish excavation work and will have to thoroughly clean the deep hole. “We would create a true synergy and transform the abandoned quarry into a rich accumulation for harsh times,” said the head of the Rijeka Waterworks. Officials involved in this innovative project are intensively collaborating with the Soška Power Plant in Nova Gorica. The designers indeed foresee, in the large quarry, also a pumping hydroelectric plant and a floating solar power plant. Pregelj sees the long-term solution for the future primarily in permanent connection of main water sources. “Water supply will have to eventually rise beyond municipal frameworks and become a national backbone, similar to the motorway crossroads or the electrical grid,” he predicted. Main state pipes would one day constantly transport raw water, while individual municipal water plants would then pump and purify it for local residents. Authorities are currently preparing only investment documentation and conceptual designs for direct connection of four coastal waterworks into a fully unified regional system. “Paperwork takes us a huge amount of time, but we are proceeding.”