Lake Garda Pollution Concerns Persist Despite Collector System Assessments
Concerns remain over pollution in Lake Garda, even though the phenomenon has been limited. The foul-smelling patch that contaminated the waters of the lower lake was sighted on Tuesday afternoon near Punta Grò, at the border with the province of Brescia. The inhuman substance, pushed by the wind, extended parallel to the shoreline for a long stretch in the direction of Sirmione.
On-site, after the alarm was triggered early that evening, the presence of the Guardia Urbana di Sirmione, Carabinieri, as well as technicians from the ASL of the Salò district, ARPAV (Venetian Regional Agency for Environmental Prevention and Protection), and the Garda Uno Consortium was confirmed. Early suspicions pointed to the collector that handles sewage discharges from both Brescia and Verona riviera towns, transferring them to the Peschiera treatment plant.
Investigations and Technical Assessments
Assessments carried out yesterday morning by technicians from the Azienda Speciale Consorzio Garda Uno and from the Gardesana Services Company of Peschiera rule out the possibility that the pollution is caused by the failure of the sewage lift station at Maraschina, the only one in the area.
«We checked the entire affected area,» says Mario Giacomelli by phone, «and found no trace of leaks. As a precaution, we pressurized the segment of the collector that had experienced some issues in the past, but no pressure drop was observed.»
The Collection System and Hypotheses on the Patch’s Origin
The sewage collection system, designed to protect the ecological integrity of Lake Garda, consists of two subsystems with collectors running along both shores, converging ultimately at the treatment plant in Paradiso, Peschiera.
It comprises a total of 134 kilometers of sewer pipes, including 19 sub-lateral pipes, served by 53 lift stations installed along the route. The aim is to boost the elevation of the sewage and enable long stretches of natural downhill flow: seen in profile, it resembles a sawtooth pattern.
Having confirmed that the serious pollution incident is not attributable to the collector, technicians believe it may be algal decay. The patch is already dissolving, and both its color and smell suggest it is linked to phenomena similar to those observed in the past, associated with algal blooms.
In recent days, water levels in the lake have decreased significantly due to extraction for irrigation, which may have caused decay near the reeds.
However, it remains necessary to await the analyses from the ASL of Salò and ARPAV of Verona to determine the true nature of the pollution.
The Carabinieri and Fire Brigade, investigating the issue, have been provided with maps of the collector routes.