## 1 Introduction  
The topic of water resource management represents a subject of frequent debate both in the political and scientific fields, since it implies the protection of fundamental rights and, at the same time, involves significant economic interests. Therefore, the management of water resources assumes a central role in the contemporary social and environmental context, in which the availability of drinking water represents a priority to guarantee the well-being of the population and the sustainability of productive activities [1]. The planning of water resource management activities presents various critical aspects since it is necessary to satisfy the demand for water in many territories and countries. The planning process requires the implementation of infrastructure, such as dams, sub-basins and reservoirs, both efficiently and effectively [2]. For this reason, many researchers are investigating the present and future challenges inherent in the sustainable management of water in urban areas [3, 4]. In recent years, demographic growth on a global scale and sectoral pressures have generated a considerable increase in water demand, triggering multiple critical issues. Among the main problems in the water sector, we highlight water scarcity, the decrease in the quality standards of the resource, losses along the distribution network and the irregularity of water supplies. These factors present a challenge for the integration of water management approaches to ensure the sustainability of the resource. Therefore, it becomes essential to adopt effective policies and strategies that ensure sustainable water management for the benefit of present and future generations [5]. The need for investment in the water sector is urgent and cannot be underestimated. Globally, around one billion people currently lack access to drinking water services, while around two billion people are unable to access adequate sanitation services. Huge investments are therefore needed in the water sector, which, unfortunately, does not receive the priority it deserves from potential investors. Lack of investment is therefore a significant obstacle. Therefore, it becomes essential to adopt appropriate measures and policies to incentivize investments in the water sector and ensure that all people have access to safe drinking water and sanitation [6]. By 2030, water demand is expected to grow by about 41%. This will require new investments in capital and knowledge to ensure the sustainability of water resources. The drinking water sector presents numerous critical issues. To be carried out efficiently, supply, collection and distribution services must incorporate innovative and sustainable technological solutions. Only in this way will it be possible to reduce waste and comply with quality standards. In general, the decrease in the final reserves of drinking water represents an important challenge that requires significant investments in water production and treatment technologies [7]. It is, therefore, necessary to increase investments in the integrated water resource management (IWRM) sector to ensure a sufficient supply of drinking water, but also an adequate treatment of wastewater. Such investments can contribute to the promotion of economic, social and environmental development. The availability of safe drinking water and adequate sanitation is essential for public health. Furthermore, investments in the IWRM sector can improve the quality of life of local communities, promote social equity and provide an opportunity for public participation in water resource management [8]. To achieve the United Nations Sustainable Development Goal 6 (SDG6), which provides universal access to safe drinking water and sanitation by 2030, a considerable increase in investments in the sector will be required. According to estimates, the necessary financing would amount to USD 114 billion a year, or three times the current level of investments.