Rapid urbanization and increasing pressure on water resources challenge the sustainability of conventional spatial planning practices. Traditional approaches, primarily based on functional zoning and post hoc infrastructure design, often neglect the dynamic relationship between urban development and water availability. This has led to overdevelopment in many regions — particularly coastal and tourism - intensive areas — where water demand exceeds supply capacity, resulting in resource stress and reduced system resilience. This study proposes a novel planning - oriented framework — the Urban Water Adequacy for Development Index (UWADI) — which integrates water resource constraints into the early stages of spatial planning. Unlike conventional assessments based on observed consumption, UWADI relies exclusively on planned development parameters, enabling prior evaluation of whether proposed urban growth is compatible with available water resources. The index is defined on a scale from 0 to 1 and consists of four components: Adequacy Deficit (AD), representing the balance between planned demand and available supply; Seasonal Exposure (SE), capturing peak demand variability; Resource Vulnerability (RV), reflecting the robustness of water sources; and Phasing Mismatch (PM), addressing the temporal alignment between infrastructure provision and development. The framework is grounded in integrated planning principles and aligned with European policy directives, including the Water Framework Directive. A structured workflow links spatial planning parameters with water resource assessments, allowing development proposals to be classified according to water adequacy thresholds and associated planning constraints. The results demonstrate that incorporating water availability as a binding constraint significantly improves the robustness and feasibility of spatial plans. The proposed UWADI framework provides a transparent and scalable tool for bridging the gap between hydrology and spatial planning, supporting more resilient, sustainable, and evidence - based urban development under increasing water stress.

Water resources in Croatia, particularly in coastal regions like Zadar County, face significant challenges due to both natural and human-induced factors. The impacts of climate change, along with rapid tourism development, pose threats not only to freshwater systems such as rivers and aquifers but also to the quality of coastal waters. Sustainable water resource management requires balancing ecological, social, and economic needs, while also ensuring these needs can be met in the future. Therefore, it is essential to quantify and assess the current state of water resources, identify potential impacts, and understand how these may evolve over time. The DPSIR (Driving forces, Pressures, State, Impacts, and Responses) framework offers a comprehensive approach for assessing and managing environmental issues, particularly in the context of water resources. It helps identify the links between potential sources of environmental problems and their consequences. In this paper, the DPSIR methodology is applied to Zadar County, Croatia — a region facing potential water-related and environmental challenges. The analysis covers the driving forces influencing water resources, the pressures on water quality and availability, the current state of various water bodies, and the resulting ecological and socio-economic impacts, as well as the responses from different stakeholders. Population growth and tourism development have been identified as the main driving forces, while increased water consumption and wastewater discharge are the primary pressures. Although the current state of water bodies is generally satisfactory, it is subject to change, which could lead to ecological, social, and economic consequences. This paper explores the complex relationship between human activities and water resource management, providing a foundation for more sustainable water management policies in the region.

Reservoirs are water management facilities that allow the regulation of the natural runoff regime. Depending on the natural characteristics of the hydrological system, the need for water and the volumetric capacity of the reservoir, and the characteristics of the evacuation organs, it is possible to manage the water resources of the basin. The increasing depletion of natural water resources and the increasing problems with meeting water needs have emphasized the need for the construction of reservoirs, often with multi-year equalization, as an integral element of integrated water resources management. Water resources management includes a number of activities such as planning, design, construction, management, maintenance, monitoring and control of constructed facilities, in order to assess and increase their efficiency. Accordingly, it is necessary to specifically plan all activities in relation to reservoirs as key facilities for managing the water regime of a basin. Keywords: multipurpose reservoir, water resources, sediment, catchment area, sedimentation, GIS modeling

In a series of exogenous and endogenous processes that cause enormous damage almost all over the world, land erosion and torrential flows occupy a special place. Torrential flows are formed practically unnoticed and represent a mixture of a large amount of eroded material from mountainous and hilly areas, which, together with water, flows down the ravines formed at a high speed into the lower parts. These streams, which in dry weather have very little flow or their beds are completely dry, in a short period of time destroy everything in front of them, from bridges, roads, to other buildings. They fill canals and agricultural land with silt, and often endanger populated areas, often with human casualties. A true example of the above was witnessed in the destruction of settlements in the municipality of Konjic and municipality of Jablanica in October 2024, where torrential rains caused huge human losses and material damage in a few hours.

The main task of the multi-purpose reservoir "Modrac" is to regulate the water regime in a given basin while making decisions on the amount of water released, as well as the amount of water that needs to be retained for future use. Decisions are made on the basis of available data and forecast data. Since no forecast model has been developed, the operator of these complex processes must rely on forecasts that are more or less precise. In practice, dam and reservoir operators, in most cases, usually follow the rules of the curves (volume, flow, etc.), which determine the actions to be taken depending on the current state of the system. With the construction of the Modrac dam in 1964, the reservoir of the same name was formed. The primary goals were to provide technical water for industry in the Tuzla region and mitigate downstream floods, as well as recreation and other purposes. The paper presents an analysis of the runoff coefficient in the correlation of annual precipitation and mean annual inflows for the catchment area of the multipurpose reservoir "Modrac" for the period 1999 - 2024. Keywords: multipurpose reservoir, runoff coefficient, precipitation, inflow, catchment area

Determining the erosion characteristics of a catchment area is very important in managing the catchment area itself, as well as in managing water resources, especially if it is a multipurpose reservoir. Factors that determine the erosion process in a watercourse catchment area, or the sediment regime of a watercourse, could be divided into those that practically do not change or those that do not change significantly over a period of several years, and factors that are subject to change during the year, depending on meteorological and climatic changes over the catchment area. For preventive action and prevention of erosion, and thus flash floods, and filling of reservoirs, it is necessary to analyze and determine precisely the erosion coefficient of the catchment area. On the other hand, water resources management includes a number of activities such as planning, design, construction, management, maintenance, monitoring and control of constructed facilities, in order to assess and increase their efficiency. Accordingly, it is necessary to specifically plan all activities in relation to reservoirs as key facilities for managing the water regime of a catchment area and processes within the catchment area. Keywords: erosion, sediment, meteorological changes, climate change, erosion coefficient, water resources, sediment, catchment area, deposition

Increasingly, and often mutually conflicting requirements for the use of water resources, there is a need for more complex management methods, including the management of the volume of reservoirs. Silt filling of reservoirs is one of the most well-known problems of river hydraulics. Dams and reservoirs, created by damming river flows, cause the retention of river sediment (drag and floating sediment) that comes from the gravitating basins, or sub-basins of the reservoir's tributaries. By analyzing the sediment transport on the tributaries, and the total amount of sediment deposited in the Modrac multi-purpose reservoir, real data are obtained on the amount of sediment introduced into the Modrac multi-pupose reservoir, the dynamics of sediment input, and the degree of pollution of this type of water body. The Modrac multi-purpose reservoir is the only available water resource in the region of Tuzla and its surroundings. Acknowledging the fact that the useful volume of the reservoir is limited, and that over time the reservoir is filled with dragged sediment and coal dust as floating sediment, and that consumers - the population, industry and others must be provided with a water supply with a high degree of safety. Excess water needs to be used to the maximum for the purpose of electricity production, and there is a need to optimize the system, i.e. more efficient management of the water resources of the reservoir, i.e. to prove the maximum utilization of the reservoir while continuously providing all the necessary amounts of water to which the Modrac multi-purpose reservoir is connected.

Multi-purpose reservoir Modrac is the most important water resource in Tuzla canton. Ecologically acceptable flow on dam Modrac is not adjusted with the latest Rulebook about methods of determining ecologically acceptable flow. This article shows the methods used to determine ecologically acceptable flow on the Modrac dam, respecting the fact that reservoir Modrac is declared as protected water resource. The given calculation of ecologically acceptable flow is made for II level of evaluation.

Multi-purpose reservoir Modrac is the most important water resource in Tuzla canton( northeastern Bosnia and Herzegovina). Ecologically acceptable flow on dam Modrac is not adjusted with the latest Rulebook about methods of determining ecologically acceptable flow. Modrac reservoir with upstream and downstream flow of Spreca river is categorized as a protected water resource due to its susceptibility to eutrophication and according to current legislation, requires a second level of ecologically acceptable flow assessment. This paper shows the methods used to determine ecologically acceptable flow on the Modrac dam, respecting the fact that reservoir Modrac is declared as protected water resource. The given calculation of ecologically acceptable flow is made for II level of evaluation

This paper examines the long-term changes in temperature and precipitation in the karst region of Imotski, Croatia, which is of particular interest due to its abundance of karst phenomena. This study analyses temperatures and precipitation on monthly and annual scales at two climatological stations in the region, Imotski and Ričice. Linear regression, the Theil–Sen estimator (β), and the Mann–Kendall test were used to determine the trends and statistical significance. The homogeneity of the data was checked using the Standard Normal Homogeneity Test (SNHT), and the F-test and t-test were used to test the significance of the mean shift between the two subseries. Additionally, the coefficient of variability, standardized rainfall anomaly, and precipitation concentration index were employed to analyze the precipitation variability. The study found a statistically significant (p < 0.05) upward trend in the mean (β = 0.0437) and maximum (β = 0.0590) annual air temperature at the Imotski station and the mean (β = 0.0387) annual temperature at the Ričice station. The SNHT test showed a statistically significant (p < 0.05) shift in the mean annual temperatures after 2007 and maximum annual temperatures after 1998 at the Imotski station. Similarly, a statistically significant (p < 0.05) shift in the mean annual temperatures after 2011 and the maximum annual temperatures after 1998 was found at the Ričice station. A seasonal distribution of precipitation is observed at both the Ričice and Imotski stations, with a downward trend (β = −2.7693) at Ričice and an upward trend (β = 6.0575) at Imotski; however, neither trend is statistically significant (p > 0.05). An increase in the intensity of dry periods and the occurrence of extreme events was also noted. The climatological analysis, conducted for the first time in this area, is a crucial step toward understanding local climate patterns and making informed decisions toward sustainable development and adaptation strategies.