Naslov
Protection of Groundwater Well Fields for the City of Zagreb Water Supplies

Autori
Bačani, Andrea ; Posavec, Kristijan ; Nakić, Zoran

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Second International Conference on Waters in Protected Areas / Nakić, Zoran - Zagreb : Hrvatsko društvo za zaštitu voda, 2007, 271-275

ISBN
978-953-96071-1-9

Skup
Second International Conference on Waters in Protected Areas

Mjesto i datum
Dubrovnik, Hrvatska, 24.04.2007. - 28.04.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
wellhead protection area; water supply

Sažetak
Citizens of Zagreb drink about 4.5 m3s-1 water pumped from the aquifer system on which the city was built (Fig. 1), therefore there is a true conflict between the city and its water supply. Pollution and contamination of the groundwater in the inflow areas and the Zagreb well fields have been confirmed (Nakić, 2003 ; Nakić et al., 2005). An obsolete and leaking sewerage has caused closing down of well fields with an approximate yield of 1.5 m3s-1 in the narrow city area. Although rather densely populated, the city outskirts are still not connected to the public sewerage. At the city territory, 837 prospective polluters have been recorded, including industrial plants, workshops and warehouses. Storage and sales of oil products at pump stations pose a particular risk for the groundwater quality. Municipal and industrial waste has been and is still sometimes tipped in numerous Sava River backwaters or abandoned illegal gravel pits without any control. Hundred and sixty-nine illegal dumpsites have been registered in the Zagreb well field catchments alone. Considerable impact on the groundwater quality is that from diffuse pollution sources, such as from agriculture, i.e. use of mineral fertilizers, fodder and pesticides for plant protection, or from depositing of air-borne heavy metals contained in exhaust gases from vehicles or industrial facilities. If the said pollution sources were added those which are commonly neglected when discussing the groundwater protection, such as the underdeveloped rainwater drainage system, salt used to prevent freezing of roads during the winter season, and even an impact the contaminated surface recipients have on quality of groundwater with which they have direct hydraulic contact, the whole situation becomes more serious and demands undertaking urgent steps. Years devoted to efforts to protect the groundwater have shown that the easiest part of the task is drafting of regulations on designation of the wellhead protection areas which stipulate behavior in such areas. The most difficult task is implementation of the groundwater quality control and protection measures set up by the regulations. The city administration has been unsuccessfully attempting to protect the city well fields since the early days of public water supplies. Such attempts particularly intensified in the second half of the 20th century. Numerous similar studies were prepared and proposals offered for the groundwater protection, and implementation of any of these proposals would have significantly contributed to improvement of the groundwater quality and quantity. Regretfully proposal neither took a form of legislation nor was implemented. The article describes the most recent proposal for designation of the Zagreb wellhead protection areas which was prepared upon request of the city authorities and in compliance with the applicable Regulation of Designation of Wellhead Protection Areas. To prepare a proposal of the Wellhead protection area II (50-day particle travel time to the water intake) and Wellhead protection area III (well field inflow area), a groundwater flow model was developed for simulation of both the flow and particle tracking. For simulation of the groundwater flow the MODFLOW program (McDonald & Harbaugh, 1988) was used. For simulation of particle tracking the MODPATH program (Pollock, 1989) which calculates particle pathlines based on the MODFLOW results was used. The graphical interface for data entry was the program package Visual Modflow Pro 4.0.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo

POVEZANOST RADA