The Bregana River is the 16.5 km long main right tributary of the Sava River on the border of Croatia and Slovenia. There are two hydrological stations on the Bregana River and one more on its main ...tributary, the Breganica River. The Bregana River drainage basin is mostly hilly and mountainous, sparsely populated, wooded, and humid, with a relatively developed stream network. The annual discharge change and the characteristics of the discharge regimes were analysed on the three hydrological stations between 1981 and 2020. No trend was recognised in mean annual discharges, but all three stations recorded a slight increase in annual minima discharges and a more pronounced increase in annual maxima discharges in the last twenty-year period (2001–2020) compared to the previous twenty-year period (1981–2000). Moreover, in the last twenty-year period, some changes occurred in the discharge regime in the research area. For all three stations in the Bregana catchment an increase in the share of annual discharge was recorded in February and March and a decrease in the share of annual discharge in December and January. Bregana River stations recorded a decreased share of annual discharge from May to July (especially in June). At all three stations, in the last twenty-year period compared to the previous twenty period, the primary maximum in March is a bit more pronounced, and the secondary maximum in December (November at Koretići station) is less pronounced. Also, for all three stations in the last twenty-year period, the primary minimum shifted from August to July and the secondary minimum shifted from February to January.
This study presents methodologically consistent length measurements of rivers with a total length of 40 kilometres or more in the Republic of Croatia. These measurements were performed by vectorising ...river channels from a topographic map at a scale of 1:25,000. Contemporary orthophoto maps were used as additional cartographic sources for verification. The approaches used to determine the starting and ending points of rivers, i.e. sources and mouths or confluences, have been explained and their spatial coordinates were listed. The results showed that in terms of total river length, the 21 rivers in this study differed from the available official data by less than 5%. Considerable differences were found for rivers where significant river engineering works had been carried out to channelize and divert flow, as well as for rivers in the Adriatic Basin where there have been methodological differences in determining the river mouth, and for large lowland rivers where changes in channel planform are common due to natural dynamics and engineering interventions. Moreover, this research revealed that the longest Croatian river, with its source, confluence, and both river banks situated entirely within the territory of Croatia, is the Karašica River, with a total length of 148 km.
This paper presents the results of the first comprehensive national analysis of changes in discharge regimes of rivers in Croatia. Seven types of discharge regimes have been defined for rivers in ...Croatia. We analyzed the changes in discharge regimes of all types, comparing the standard period from 1961 to 1990 with the most recent period from 1990 to 2009. We found evidence of a redistribution of discharge throughout the year, an increase in autumn and winter discharges (especially for rivers dominantly fed by snowmelt), and a decrease in summer discharge values. Furthermore, we detected a change in the month of the appearance of mean discharge maxima and minima. In most cases, the changes can be explained by changes in the regime of climate elements (temperature, precipitation, and evapotranspiration). The results are consistent with those from upstream countries; that is, Slovenia, Austria, and Bosnia and Herzegovina.
U radu se istražuje kakve se promjene u godišnjoj količini padalina u Hrvatskoj mogu utvrditi od sredine 20. stoljeća do danas. Na temelju podataka za 22 postaje linearni trendovi za razdoblje 1950. ...– 2010. pokazuju vrlo male promjene. U istočnoj Hrvatskoj evidentan je blagi porast; a u ostalim krajevima utvrđen je blagi pad ili stagnacija. Ipak; kada bi se takvi trendovi nastavili; dugoročno bi mogli imati geografske posljedice. U analiziranom razdoblju moguće je utvrditi i cikličke promjene godišnje količine padalina
The paper deals with the annual mean amounts, the intensity and the probability of precipitation in the drainage area of the river Sana (in the northwestern part of Bosnia and Herzegovina). ...Generally, the Sana drainage area is a humid region. Thus, the annual precipitation measured in most of the meteorological stations clearly shows two maximums – in November and in June. Almost every station included in the research shows a continental pluviometric pattern, while more significant maritime influence is shown in the stations positioned in the west, the southeast and the south of the researched area. The monthly fluctuations in precipitation are considerable. The precipitation are most likely to occur during summer and spring, while the annual intensity of precipitation in nine considered stations is 8.06 l/m2.
Suvremena vodoopskrba riječkog područja Grbac Žiković, Renata; Orešić, Danijel; Čanjevac, Ivan
Geoadria,
01/2017, Letnik:
14, Številka:
2
Journal Article, Web Resource
Recenzirano
Odprti dostop
The area of Rijeka's water supply system belongs to karst which is featured with a significant underground water circulation, as well as with a high sensitivity to external influences such as water ...pollution. Abundant springs are the basis of water supply. The minimal spring abundance exceeds the water consumption for several times. The quality of water is good, supplying more than 200.000 residents of the Rijeka area, and since lately the northern part of Krk Island. The article studies the development of Rijeka's water supply system, with an emphasis on the water consumption and the level of water supply system's development in the last fifteen years. The data shows a high level of development of the water supply system. Lately there has been a decrease in water consumption in the researched area, particularly in economic sector due to many industries being shut down. Today approximately 2/3 of consumption accounts for households. In spite of redistribution of population within the researched area (the process of suburbanization) there was no significant decrease in water supply standard. Moreover, lately there have been considerable advances in reducing the losses in the water supply network.
The Krka River and its tributaries make the system of composite valleys in the karst. The composite valley system is the result of lithologic and tectonic relations. The Krka valley is of polygenetic ...origin. In the canyon sections there are many characteristic slope relief details. On steeper slopes crumbling and collapsing is significant. The debris of surrounding rocks is found in alluvial deposits at the valley widening. In recent times, the regeneration of vegetation is noticeable, which contributes to decreasing intensity of relief shaping by exogenic processes.
In order to analyse discharge regimes in the middle course of the Sava River (Croatia and Bosnia and Herzegovina), three hydrologic stations were chosen, having homogenous as well as continuous data ...in the observed 1931–2010 period. Those stations are Rugvica at the beginning of the middle course of the Sava River, station Jasenovac located just forehead of the Una River mouth and all the other large tributaries from Bosnia and Herzegovina and station Županja near the end of the middle course of the Sava River. At all three stations, there are notable negative trends of annual mean (all stat. significant) and minimum discharges for the whole period. At the same time, only in the upper part of the middle course of the Sava River maximum annual discharges have a positive trend, contributing to more unfavourable regime characteristics. At all three stations a cyclic variation of mean annual discharges is observed, likely to be linked to the cyclic variation of annual precipitation in the area of the basin. According to the latest discharge regime typology of the region the discharge regime at Rugvica is of Peripannonian pluvial-nival type, while the discharge regimes downstream, at Jasenovac and Županja fall into Pannoninan pluvial-nival type. A comparison of discharge regimes established for two past climatological standard reference periods 1931–1960 and 1961–1990 as well as for the contemporary 30-year period 1981–2010 lead to a conclusion that important changes in mean monthly discharges yearly course already occurred in the climatological standard reference period 1961–1990 compared to the previous one. In 1961–1990 period the autumn season discharge decreased, which is almost solely a result of a large fall in the November mean monthly discharge at all stations. Furthermore, in the same 1961–1990 period a transition of the primary maximum in the annual course of mean monthly discharges from November to December and of the secondary maximum from March to April occurred, which is preserved in discharge regimes in the middle course of the Sava River. Discharge regimes in the middle course of the Sava River in the contemporary period are characterised by decreased summer and even spring time discharges, which is linked to the trend of raising air temperatures, an increase in potential and real evapotranspiration and to a slowly decrease in annual precipitation, particularly in the summer season as established in spatially relevant previous climatological research.
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