<p>The transboundary aquifers are of utmost importance to sustain water supply in present days. The exploitation of these aquifers has to be only in a sustainable and rational way, in order to sustain the quantity and quality of the aquifers' groundwater. A transboundary aquifer is developed in karstified limestones between the lakes Great Prespa (shared between North Macedonia, Albania, and Greece ) and Ohrid (shared between North Macedonia and Albania). The karst mountainous area is characterized by the presence of numerous crevices, sinkholes, as surface forms, and caves, canals, etc., as underground forms. The elevation of Prespa Lake is about 153 m higher than that of Ohrid Lake, and the two lakes represent a common hydraulic system, protected by international conventions. Prespa Lake is characterized by a continuous decline in water level during the last decades. The transboundary karstic aquifer is a complex system, discharging through numerous karstic springs (e.g., Saint Naum, Tushemisht, etc.), and operating as a hydrocollector and hydroconductor between the lakes. The aquifer is vulnerable to external pollution, as well as to climate changes affecting the lakes&#8217; ecosystems. Agriculture, livestock, and tourism are the main activities in the wider area.</p><p>The DPSIR (Driver-Pressure-State-Impact-Response) model, adopted by European Environmental Agency, was applied in GIS context, in order to study and analyze the main causes of pressures and to optimize the measures for integrated aquifer management. In addition, the aim of DPSIR technique is the correlation of the driving forces and pressures with the present status of the complex hydraulic system and finally to optimize the aquifer management. The major driving forces that affect the Prespa-Ohrid basin are the irrigated agriculture, the livestock, the tourism development, and population growth. The main pressures are the overexploitation of the aquifer, water pollution, and the decline of the water level of Lake Prespa.</p><p>Based on the results of DPSIR, a set of measures and appropriate policy responses are proposed. Finally, DPSIR is a valuable tool for local authorities and administrators in order to plan and implement strategies for integrated and sustainable management of the transboundary karst aquifer and its dependent ecosystems.</p>
Evaluating international support for transboundary aquifer management programmes
