## 2 Materials and Methods  
### Study Area  
Farsala is a city of 9144 inhabitants in the southern part of west Thessaly in central Greece and is geographically located at 39\({}^{\circ}\)17\({}^{\prime}\)28\({}^{\prime\prime}\)-39\({}^{\circ}\)18\({}^{\prime}\)18\({}^{\prime\prime}\) N latitude and 22\({}^{\circ}\)21\({}^{\prime}\)54\({}^{\prime\prime}\)-22\({}^{\circ}\)24\({}^{\prime}\)00\({}^{\prime\prime}\) E longitude (Figure 1). The climate of the region is continental, with cold winters and hot and dry summers, with the temperature difference between these two seasons being significant. In July and August, the maximum observed temperature exceeds 40 \({}^{\circ}\)C, and in December and January, the minimum observed temperature reaches -10 \({}^{\circ}\)C. The mean annual precipitation is ca. 513 mm, and the mean annual evapotranspiration is ca. 415 mm [30]. It covers an area of ca. 3 km\({}^{2}\), and the surface elevation varies from 235 m in the south to 132 m in the north.  
Figure 1: (**a**) Orientation map of the wider area of the city of Farsala; (**b**) satellite image of the city of Farsala and a digital elevation model (DEM) of the wider area.  
The Water District of Thessaly, with an area of 13,377 km\({}^{2}\), consists of two large watersheds: (i) the Pinios River watershed, which occupies the largest area (84.2%), and (ii) the streams of the Pilon mountain and the Almiros area watershed, which is located in the eastern and coastal part of Thessaly [31]. The study area belongs to the Pinios River's watershed, and all the water uses are covered by groundwater, since there are no permanent surface waters apart from the existing rivers with seasonal flows.  
Specifically, the wider area of Farsala city is one of the most productive agricultural regions in Greece, and an economic and agricultural center of the region [32]. Cotton and livestock are the main agricultural products, and many inhabitants are employed in factories for the production of textiles. The water supply of Farsala city is entirely covered by the groundwater system of southwestern Thessaly (EL0800030), which is in a bad quantitative and chemical condition according to the River Basin Management Plan of Thessaly [33]. The long-term intensive cultivation of water-demanding crops and the excessive use of nitrogen fertilizers have led to the overexploitation of permanent groundwater resources and the presence of nitrates with high concentration values.  
The water distribution network of Farsala is a representative example of a small provincial municipality facing challenges due to aging infrastructure, rapid urban expansion, data scarcity, and water resources' quantity and quality issues. The total network length is 59.8 km, including a 7.055 km feeder main and 5.72 km of distribution mains. The network supplies water to approximately 4860 registered consumers, with an annual water supply volume of 1.67 km\({}^{3}\) in 2022. The network was first constructed in 1981, with minor expansions and pipe replacements occurring in 2004 and 2006. However, the water network of the city of Farsala does not include any pressure control zones, and much of the system remains outdated and unmapped, resulting in excessive water losses and operational inefficiencies. The aging infrastructure, significant elevation differences, and lack of necessary control equipment contribute to pressure imbalances and inefficiencies. In addition, the city currently has fire hydrants only in public areas, and the lack of historical records on pipeline materials, valve placements, fire hydrant locations, and damage points complicates network management, further limiting emergency response capabilities.