“The analysis of dry water periods in the Krka River basin and hydrological elements of an ecologically acceptable flow and the impact of extreme droughts on water-dependent ecosystems”
Defining and ensuring environmentally acceptable flows (EF) in watercourses of protected areas is of crucial importance for the maintenance of water-dependent ecosystems during prolonged dry periods
This is the case with the waters in the Krka National Park, and it is especially important in terms of the processes of tufa formation on the tufa barriers of the Krka River.
With the aim of ensuring an adequate basis for determining the EF in the area of the Krka National Park, where there are pronounced anthropogenic pressures related to the use of water, especially for energy needs, during 2023 and 2024 the company GEO-5 d.o.o. from Rovinj, in cooperation with the Faculty of Civil Engineering in Rijeka and the company Dvokut-ECRO d.o.o., conducted research into the hydrological elements of the EF: the water regime of the Krka River, low water periods, and the influence of the existing water use regime on the water balance. As part of the research, a contribution was made to the development of a new methodology for determining the hydrological elements of the EF in such a way that the wetted rim method commonly used was improved by planar observations of the wetted surface of the barrier where processes of tufa coalescence are present.
On three occasions, recordings of the Manojlovac waterfall barrier were taken, using an unmanned aerial vehicle (drone), a 3D scanner, a digital camera, and an RTK GPS device. Based on photos taken with the digital camera and the drone camera, a three-dimensional cloud of points was created, generated by Structure-from-Motion (SfM) photogrammetry, processed, and geo-referenced.
In the referential document, data on the underground ecosystem of the Miljacka II cave was collected and analysed, and the potential use of protists as indicators of the state of hydrological conditions underground was investigated. Research has shown that encased amoebas, as the most diverse and largest group of subterranean protists, are the most suitable for statistical processing, with the purpose of determining the ecological characteristics existing in the cave.
The conducted investigation and documentation of above-ground and underground parts of the water course confirmed the ever increasing influence of climatic variations and changes on the ecosystem of the Krka River, while analyses of low-water periods show negative changes, which are expected to intensify in the future.
Research
JOŠ NOVOSTI IZ KATEGORIJE
Investigation of the condition and composition of the macrozoobentos of the tufa barriers of the Krka River
During 2024 and 2025, an extensive scientific study of the composition and condition of macrozoobenthos (benthic invertebrates) was conducted on all seven tufa barriers of the Krka River
Monitoring the status of the target fish species Canostrini's Goby (Pomatoschistus canestrinii) and the Dalmatian barbelgudgeon (Aulopyge huegelii)
Monitoring the status of the target fish species Canostrini's Goby (Pomatoschistus canestrinii) and the Dalmatian barbelgudgeon (Aulopyge huegelii)
Research into the state of freshwater prawns in the estuary of the Krka River
Estuary ecosystems, such as the Krka River estuary, are biologically highly productive systems with net primary production rates among the highest in the world
Investigation of the morphology of the tufa barriers at Manojlovac waterfall in the Krka NP through the use of remote sensing research
The project "Investigation of the tufa barrier of Manojlovac waterfall using remote sensing" is focused on the development, application, and evaluation of modern remote sensing methods in the documentation, analysis, and monitoring of the state of the tufa barriers