Assessing low flow water resources

Abstract

The reasons of choosing the current subject were the changes in the hydrological regime of rivers in Hungary observed during the preparation of Integrated Water Management Plan (IWMP). The latter one constituted a part of river basin management plans (RBMPs) created within the EU's Water Framework Directive (WFD). The current paper reviews the changes in the river flow regimes those entering the Hungarian territories as well as the underlying hydrometeorological interactions in the upper river basins. It must also be taken into account that the water resources generated in the upper river catchments are of exceptionally importance for Hungary, while their use upstream from other the state borders are also increasing. The water demands are increasing in Hungary because of the gross of industrial and agricultural production. Based on the facts, it is necessary to devote increasing attention to the assessment of water resources during the low flow periods. It is also required to study the possibility of future changes in the hydrological regimes. Consequently, the need for updating the assessment of low flow values, which are laying the foundations for water use permitting procedures is obvious. The frequent droughts and as an outcome, the restricted water uses force the authorities to update the governing documents and along these the action plans. The paper is screening the approaches applied in assessing the low flow water recourses applied in Hungary as well as in the international practice. The necessary updating of the currently applied methodology in water resource assessment required a new approach in water balance computations. The paper provides an overview about the uncertainties occurring in the assessment of water resources design values. Special attention is paid to the catchments not being monitored. The national and international approaches to assess the water resource design values are elaborated. The paper in the end collects the tasks for the Hungarian Water Sector in order to ensure an effective water resource management in the future. The authors emphasize that special attention should be paid to the water management co-operations in the bilateral cross-boundary contexts as well as in basin-wide frameworks and under the aegis of international organisations. The importance of implementation of water resources management that points beyond the traditional practice of running the water sector is highlighted.