History of project development
The idea of the need for an integral water protection on the territory of the Istrian peninsula stems from the 1980s, when the construction of the Istrian water supply system – Butoniga Waterworks commenced. The new water supply project imposed the need for the integral water supply and drainage management to protect limited water resources arising from the specific features of the Istrian peninsula which had been observed even earlier.
All main captured drinking water sources: Sv.Ivan, Gradole, Bulaž, Rakonek, Kokoti, Fonte Gaia, etc., are located in the Istrian hinterland. The sources are of a karst ascenting type, which abundance ranges from large quantities of water during rain seasons often accompanied by turbidity and pollution to a very limited water quantity during drought periods.
This project, based on the study commissioned by the Region of Istria and Hrvatske vode back in 2000: ' The organization, construction and maintenance of the wastewater drainage and treatment system for small settlements within the water protection area in the Region of Istria', encompassed 173 settlements under zones of sanitary protection of drinking water sources in Istria'. The idea of the need to build the wastewater drainage and treatment system in small settlements located in the Istrian hinterland was imposed by soil configuration specific features, which is mainly made of karst, as well as by the location and characteristics of main drinking water sources which supply not only local inhabitants but also the business of tourism. The project encompassed small settlements without any economic or human resources for the construction and management of the sewage system.
As the entire Istrian subterranean area is one aquifer, the integrated water supply and drainage system management must be introduced.
At the same time, as water consumption during summer is double the winter volume due to intensive development of tourism, the integrated water supply management is needed along with the existance of the backup system – the accumulation. In light of the aforementioned, a part of the water supply system in coastal towns, Rovinj and Pula in particular, has been carried out as a project of water supply from the Butoniga artificial accumulation located in the heart of the peninsula, on the area featuring the towns of Pazin, Buzet and the Cerovlje municipality, which has become one of the main water supply sources, especially during summer.
At that time, Decisions on Zones under Sanitary Protection of Individual Drinking Water Sources which were in force in Istria regulated the level of passive and active protection across a wider area of each of said sources. Passive protection defines the activities which are limited or forbidden, while the active one regulates waste and wastewater disposal in protection zones to the maximum extent possible. As the entire Istrian subterranean area is one aquifer for all drinking water sources due to soil configuration and its karst characteristic, the need for the adoption of wastewater discharge and treatment plan across the entire area arose. Those waters, if discharged underground in an uncontrolled fashion, represent the highest risk factor in terms of groundwater pollution and thus of water supply sources.
The modern approach to wastewater management requires used water discharge into the public drainage system, its purification and further use or its return into nature with no harmful consequences. In view of the unique Istrian feature of being a single aquifer, the drinking water sources need to be made safe by a controlled wastewater drainage and treatment system across the peninsula.