Der Einfluss der hydrotechnischen Bauten auf das Wasserregime der Baćina-Seen

Analizirani su karakteristični (minimalni, srednji, maksimalni) dnevni, mjesečni i godišnji vodostaji opaženi na vodomjeru Šipak lociranom u jezeru Sladinac, jednom od pet povezanih jezera (Plitko, Podgora, Očuša, Sladinac, Crniševo) i jednom nepovezanom jezeru (Vrbnik) u sustavu Baćinskih jezera. Na raspolaganju je stajao niz dnevnih vodostaja od 1. siječnja 1923. do 31. prosinca 2018., s prekidima od 1. listopada 1942. do 31. lipanja 1945. te od 1. siječnja 1959. do 31. prosinca 1972. Analize su usredotočene na to da se kvantificira utjecaj antropogenih zahvata na vodni režim sustava Baćinskih jezera. Tunel Krotuše kojim se evakuiraju poplavne vode iz Vrgorskog polja te upuštaju u sustav Baćinskih jezera počeo je s radom 21. studenog 1938. Rekonstruiran je u nekoliko navrata, najopsežnije krajem1973. godine. Tunela koji iz Baćinskih jezera u Jadransko more evakuira vodu pušten je u rad krajem 1912. Radovi na njegovom proširenju vršeni su u razdoblju od kraja 1938. godine do početka 1940. U razdoblju 1982.-1993. iz ulaza u ovaj tunel uklonjen je prag visine 80 cm koji je sprječavao prodor morske vode u sustav jezera tijekom plima. Detaljnim statističkim analizama zasnovanim na primjeni F- testa (Markowski i Markowski, 1990.) i t-testa (Machiwal i Jha, 2008.) ustanovljen je utjecaj svakog od pojedinih navedenih zahvata na promjenu vodnog režima sustava Baćinskih jezera na vremenskoj skali godine i mjeseca. Utvrđeno je kontinuirano opadanje srednjih godišnjih razina vode mjerenih na vodokazu Šipak. Uočen je stalni porast maksimalnih godišnjih vodostaja.The analysis included the characteristic (minimum, average and maximum) daily, monthly and annual water levels at the water meter Šipak, which is located in Sladinac Lake, one of the five connected lakes (Plitko, Podgora, Očuša, Sladinac and Crniševo Lakes) and one unconnected lake (Vrbnik Lake) in the system of Baćina Lakes. A series of daily water levels from 1 January 1923 to 31 December 2018 was available, with interruptions from 1 October 1942 to 31 June 1945 and from 1 January 1959 to 31 December 1972. The analyses focused on the quantification of anthropogenic interventions on the water regime of the system Baćina Lakes. The tunnel Krotuše, which is used for evacuating flood water from the karst field Vrgorac and letting it into the system Baćina Lakes, started operating on 21 November 1938. It was reconstructed several times, the most comprehensively at the end of 1973. The tunnel evacuating water from Baćina Lakes to the Adriatic Sea started operating at the end of 1912. The works on its extension were carried out in the period from the end of 1938 to the beginning of 1940. In the 1982 - 1993 period, a 80 cm tall sill preventing seawater intrusion into the lake system during tides was removed from the tunnel’s entrance. Detailed statistical analyses based on applying the F test (Markowski and Markowski, 1990) and t-test (Machiwal and Jha, 2008) determined the impact of each individual mentioned intervention on the change in the water regime of the system Baćina Lakes on the year-and-month time scale. A continuous decrease in the average annual water levels was measured at the water meter Šipak. A permanent increase in the maximum annual water levels was determined as well.Die charakteristischen (minimalen, mittleren und maximalen) Tages-, Monats- und Jahreswasserstände sind analysiert worden, die am Pegelstand Šipak am See Sladinac (einer von fünf miteinander verbundenen Seen, nämlich Plitko, Podgora, Očuša, Sladinac und Crniševo) und an einem selbständigen See (Vrbik) im Baćina-Seensystem gemessen wurden. Eine Reihe von Tageswasserständen vom 1. Januar 1923 bis 31. Dezember 2018, mit den Unterbrechungen zwischen 1. Oktober 1942 und 31. Juni 1945 und zwischen 1. Januar 1959 und 31. Dezember 1972, stand zur Verfügung. Die Analysen konzentrierten sich auf die Quantifizierung des Einflusses von anthropogenen Eingriffen auf das Wasserregime des Baćina-Seensystems. Der Tunnel Krotuša, durch welchen Hochwasser aus dem Vrgorac-Feld in das Baćina-Seensystem geleitet wird, wurde am 21. November 1938 geöffnet. Er wurde mehrmals renoviert, die größte Renovation fand Ende 1912 statt. Der Tunnel, durch welchen das Wasser aus den Baćina-Seen ins Adriatische Meer geleitet wird, wurde Ende 1912 geöffnet. Die Verbreitungsarbeiten wurden im Zeitraum zwischen Ende 1938 und Beginn 1940 durchgeführt. Von 1982 bis 1993 wurde am Tunneleigang eine 80 cm hohe Schwelle entfernt, die das Eindringen des Meereswassers in das Baćina-Seensystem bei Flut verhinderte. Mit weiteren statistischen Analysen anhand vom F-Test (Markowski und Markowski, 1990) und t-Test (Machiwal und Jha, 2008) wurde der Einfluss jedes einzelnen technischen Eingriffs auf die Änderung des Wasserregimes des Baćina-Seensystems auf der Zeitskala von Jahr und Monat festgestellt. Es wurde eine kontinuierliche Verringerung von mittleren am Pegelstand Šipak gemessenen Jahreswasserständen festgestellt. Es wurde auch eine ständige Erhöhung der maximalen Jahreswasserstände beobachtet

Different Climate Changes at Two Locations on a Small Karst Island Korčula (Adriatic Sea, Croatia)

The article analyses the series of annual, monthly and daily air temperatures and annual and monthly rainfall at two meteorological stations in Vela Luka and Korčula on the island of Korčula (Croatia), for which there are long time series of observations. Today’s locations of meteorological stations are only 33.5 km apart. The average annual air temperature at the Vela Luka station is on average 1°C lower than that measured at the Korčula station. A significant upward trend in mean annual and mean monthly air temperatures was observed at both stations, with the increase being much milder at the Vela Luka station. Warming processes are significantly faster at the Korčula station than at the Vela Luka station. Significantly different values of air temperatures, and in particular the fact of different reactions of air temperatures to climate change at two stations, can be explained by their local position in relation to the open sea and orography of the surrounding terrain. While the Vela Luka station is exposed to the open sea and away from the mainland, at Korčula station the impact of the sea is less significant because the sea is located in a narrow channel between the island of Korčula and the Pelješac peninsula. The distance of the Korčula meteorological station from the Pelješac peninsula and the mainland is significantly smaller, which affects the faster trend of rising air temperatures at this station than at the Vela Luka station, where the influence of the sea mitigates the effect of global warming. Orography and proximity to land affect significantly higher rainfall occurrences at Korčula station. Average annual rainfall at this station is 231 mm or 27.5% higher than at Vela Luka station. Both stations show a trend of decreasing annual rainfall

Water resources analysis of the Rječina karst spring and river (Dinaric karst)

The paper deals with complex hydrological/hydrogeological behaviour in the Rječina karst spring and river basin located in the north-western part of the deep and developed Croatian Dinaric karst. The Rječina Spring is one of the major karst springs in Croatia, used for water supply of Rijeka City and its surrounding area. Beside the use of Rječina spring for water supply, the development of the Rijeka hydroelectric power plant (HEPP) also changed hydrological and hydrogeological regime of the whole catchment. In order to analyse the anthropogenic influences in the system, hydrological analysis of the Rječina river and spring discharge was done, as well as the analysis of the available data of groundwater measurements. The analysis showed that, due to the increase of water caption and decrease of precipitation, the average annual spring discharge decreased for approximately 25% in the 1980-2016 period. Detailed analysis of groundwater measurements indicated aquifer behaviour and the need for additional measurements and catchment delineation.Key words: hydrology, hydrogeology, karst, Rječina Spring, Rječina River, Dinaric karst.Analiza vodnih virov kraškega izvira in reke Rječina (Dinarski kras)Članek obravnava zapletene hidrološke/hidrogeološke razmere v zaledju kraškega izvira in reke Riečine v severozahodnem delu globokega in dobro razvitega hrvaškega Dinarskega krasa. Izvir Rječina je eden največjih kraških izvirov na Hrvaškem, zajet je za oskrbo s pitno vodo za mesto Reka in njeno okolico. Poleg rabe izvira Rječine za oskrbo z vodo je razlog za spremenjen hidrološki in hidrogeološki režim celotnega zaledja tudi gradnja hidroelektrarne Reka (HEPP). Za analizo antropogenih vplivov na sistem smo zato naredili hidrološko analizo pretokov reke in izvira Rječina pa tudi analizo razpoložljivih podatkov merjenja podzemne vode. Analiza je pokazala, da se je zaradi povečanja zajemanja vode in zmanjšanja količine padavin povprečen letni pretok izvira v obdobju 1980–2016 zmanjšal za približno 25 %. Podrobna analiza meritev podzemne vode je nakazala značilnosti delovanja vodonosnika ter pokazala potrebo po dodatnih meritvah in določitvi zaledja izvira.Ključne besede: hidrologija, hidrogeologija, kras, izvir Rječina, reka Rječina, Dinarski kras

Analyse der wasserentnahme aus der quelle des flusses Jadro im zeitraum 2010-2021

U članku su analizirani nizovi srednjih dnevnih, mjesečnih i godišnjih protoka Jadra mjereni na tri vodomjerne postaje (Jadro-Majdan, Jadro-Novi kanal, Jadro-Dioklecijanov kanal) u razdoblju od 1. siječnja 1995. do 31. prosinca 2021. Osnovni cilj istraživanja opisanih u ovom radu bio je da se usporede količine odvođenja vode iz izvora Jadra u vodoopskrbni sustav u razdoblju 1995. - 2009. s onima u recentnom razdoblju 2010. - 2021. U posljednjih 12 godina došlo je do pozitivnog pomaka, tj. iz izvora Jadra prosječno se godišnje bespovratno odvodi manje vode nego u razdoblju 1995. - 2009. Bitno je napomenuti da je trend opadanja u recentnom razdoblju statistički značajan. Važno je naglasiti da problemi i dalje postoje prvenstveno stoga jer se tijekom toplog razdoblja godine od lipnja do rujna situacija još uvijek nije bitno poboljšala. Ključan problem javlja se u srpnju i kolovozu tijekom kojih se još uvijek iz izvora odvodi više od 40 % vode. Realno je očekivati da će odvođenje, kao posljedica globalnog zagrijavanja temperature zraka u regiji, rasti u budućnosti. Tijekom ljetnog i beskišnog razdoblja intenzivirat će se pojave suša što bi moglo rezultirati ponovnim povećanjem odvođenja vode iz izvora Jadra. Neophodno je i dalje raditi na smanjivanju bespovratnog odvođenja vode iz izvora i stvaranju pouzdanog i održivog sustava upravljanja ovim neprocjenjivo vrijednim vodnim resursom.The paper analyses the series of average daily, monthly and annual discharges of the Jadro River source measured at three hydrological stations (Jadro-Majdan, Jadro-Novi Kanal, Jadro-Dioklecijanov Kanal) in the period from January 1, 1995 to December 31, 2021. The main goal of the research described in this paper was to compare the quantities of water abstracted from the Jadro source into the water supply system in the period 1995-2009 with those in the recent 2010-2021 period. There has been a positive shift in the past 12 years, i.e. on average, less water is annually abstracted from the Jadro source than in the period 1995-2009. It is important to note that the downward trend in the recent period is statistically significant. It is also important to note that the problems still exist, primarily because the situation during the warm period of the year from June to September has not significantly improved. The key problem occurs in July and August, when more than 40% of the water from the source is still abstracted. It can be realistically expected that the air temperatures in the region will rise in the future as a consequence of global warming. Drought occurrences will intensify during the summer and periods without rain, which could result in a renewed increase in water abstraction from the Jadro source. It is necessary to continue the work on reducing the irreversible removal of water from the source and creating a reliable and a sustainable management system for this invaluable water resource.Im Artikel werden die Reihen von mittleren täglichen, monatlichen und jährlichen Durchflüssen des Flusses Jadro analysiert, die an drei Wassermessstationen (Jadro-Majdan, Jadro-Novi Kanal, Jadro- Dioklecijanov Kanal) im Zeitraum vom 1. Januar 1995 bis 31. Dezember 2021 gemessen wurden. Das Hauptziel der in diesem Artikel dargestellten Untersuchung war, die Wassermengen, die von der Jadro-Quelle entnommen und in das Wasserversorgungssystem im Zeitraum 1995-2009 abgeleitet wurden, mit den im Zeitraum 2010-2021entnommenen Wassermengen zu vergleichen. In den letzten 12 Jahren gab es eine positive Verschiebung, nämlich, aus der Jadro- Quelle wird jährlich durchschnittlich weniger Wasser abgeleitet, als das im Zeitraum 1995-2009 der Fall war. Es ist wichtig zu beachten, dass der Abwärtstrend im letzten Zeitraum statistisch signifikant ist. Es ist aber auch wichtig zu betonen, dass Probleme weiterhin bestehen, vor allem weil sich die Situation während der warmen Jahreszeit von Juni bis September noch immer wesentlich nicht verbesserte. Das Hauptproblem entsteht in Juli und August, wenn aus der Quelle noch immer mehr als 40% des Wassers abgeleitet wird. Es ist realistisch zu erwarten, dass die Lufttemperaturen in der Region aufgrund der Auswirkungen der globalen Erwärmung auch in Zukunft steigen werden. Im Sommer und in der regenfreien Zeit werden Dürren verstärkt, was zu einem erneuten Anstieg der Wasserableitung aus der Jadro-Quelle führen könnte. Es muss weiter an der Reduzierung der Ableitung von Wasser aus der Quelle und an der Schaffung eines zuverlässigen und nachhaltigen Managementsystems für diese unschätzbare Wasserressource gearbeitet werden

Nasute građevine

Ova knjiga svojim sadržajem popunjava prazninu u području geotehničkih građevina na hrvatskom jeziku. Uz do sada objavljenje tekstove o potpornim građevinama, građevnim jamama, složenom temeljenju, poboljšanju podtemeljnog tla i zemljanim radovima, u području geotehničkih građevina ostaje prostor za nasute građevine. Nasute građevine imaju zajedničko to što im je tlo gradivo, a svaka od njih ima svoje posebnosti. Neke od navedenih građevina mogu biti vrlo jednostavne, s malim zahtjevima, dok druge zahtijevaju veliku pažnju i složene proračune pri projektiranju. Spadaju u vrstu građevina bez očitih temelja, s tlom kao gradivom u kontroliranim i nekontroliranim uvjetima ugradnje. Nasute građevine su geotehničke građevine i kao takve zahtijevaju temeljita i sveobuhvatna geotehnička rješenja. Tekst sadrži dva dijela; dio I, Tlo kao gradivo i dio II, Nasipi. I dio bavi se vrstama tla, ispitivanjem, utjecajem zbijanja na svojstva tla i provjerom kakvoće ugrađenog tla. Dio II bavi se nasipima kao građevinama s naglaskom na hidrotehničke nasipe i male brane

Analysis of daily, monthly and annual precipitation at the Zagreb-Grič observatory (1862 -2017) for purposes of engineering hydrology

U članku je izvršena analiza dnevnih, mjesečnih i godišnjih količina oborine izmjerenih na opservatoriju Zagreb-Grič u razdoblju od 1862. do 2017. čime je obuhvaćeno: (1) 156 godina; (2) 1872 mjeseca; (3) 56.979 dana. Za analizu su korištene sljedeće metode: (1) linearna i nelinearna regresija; (2) linearna i nelinearna korelacija; (3) krivulje log-normalne raspodjele; (4) test Kolmogorov-Smirnova; (5) Mann-Kendall test; (6) RAPS metoda; (7) t-test; (8) F-test. Godišnje se oborine kreću u rasponu od 520,8 mm (2011.) do 1387,4 mm (1937.) s prosječnom vrijednosti od 886,7 mm. Maksimalne mjesečne oborine koje su se pojavile u svakoj pojedinoj godini kreću se u rasponu od 85,3 mm (lipanj 2011.) do 267,5 mm (listopad 1895.) s prosječnom vrijednosti od 158,1 mm. Maksimalne dnevne oborine koje su se pojavile u svakoj pojedinoj godini kreću se u rasponu od 21,7 mm (14. studenog 1949.) do 118,8 mm (9. kolovoza 1926.) s prosječnom vrijednosti od 47,6 mm. Maksimalnoj dnevnoj oborini od 118,8 mm odgovara povratni period dulji od pet tisuća godina. Ne može se konstatirati prisutnost statistički značajnog trenda porasta ili opadanja kako u nizovima godišnjih tako i mjesečnih (osim u listopadu) kao i maksimalnih dnevnih oborina u godini i mjesecu. Utvrđeno je da samo u listopadu postoji statistički značajna razlika količina oborina u sljedeća dva podrazdoblja: (1) 1862.-1941.; (2) 1942.-2017. U prvom podrazdoblju prosječna mjesečna količina oborina iznosila je 105,1 mm dok je u drugom pala za 29 mm te je iznosila 76,1 mm. Na osnovi analiza izvršenih u ovom radu može se donijeti zaključak da na oborine raznih vremenskih trajanja izmjerene u razdoblju 1862.-2017. na opservatoriju Zagreb-Grič ni klimatske promjene kao ni proces urbanizacije nisu značajno utjecali.The paper conducts the analysis of daily, monthly and annual precipitation quantities measured at the Zagreb-Grič observatory in the period from 1862 to 2017, which comprises of: (1) 156 years; (2) 1,872 moths and (3) 56,979 days. The analysis uses the following methods: (1) the linear and non-linear regression; (2) linear and nonlinear correlation; (3) log-normal distribution curves; (4) Kolmogorov–Smirnov test; (5) Mann-Kendall test; (6) RAPS method; (7) t-test; (8) F-test. The annual precipitation ranges from 520.8 mm (2011) to 1387.4 mm (1937), with an average value of 886.7 mm. The maximum monthly precipitation occurring in each individual year ranges from 85.3 mm (June 2011) to 267.5 mm (October 1895), with the average value of 158.1 mm. The maximum daily precipitation occurring in each individual year ranges from 21.7 mm (14 November 1949) to 118.8 mm (9 August 1926), with the average value of 47.6 mm. The maximum daily precipitation of 118.8 mm equates to a return period of over five thousand years. The presence of a statistically significant upward or downward trend in the annual or monthly (expect in October) precipitation series as well as maximum daily precipitation in a year or a month cannot be confirmed. The presence of a statistically significant difference in the precipitation quantities has been determined only for October, and comprises of two sub-periods: (1) 1862-1941 and (2) 1942-2017. In the first sub-period, the average monthly precipitation quantity equalled 105.1 mm whereas in the second sub-period it decreased by 29 mm and equalled 76.1 mm. According to the analyses conducted in this paper, it can be concluded that the precipitation of different time durations measured in the period from 1862 – 2017 at the Zagreb-Grič observatory showed no significant impact of either the climate change or urbanisation

Flood embankments – calculation according to Eurocode

Nasipi za obranu od poplava su geotehničke građevine. One su bitne građevine za zaštitu ljudskih života i materijalnih dobara. Eurocode 7: Geotehničko projektiranje-dio 1.: Opća pravila, o njima ne vodi dovoljno računa. Projektanti su dužni pridržavati se naputaka iz ovog propisa, a oni se nalaze u nekoliko poglavlja EC7/1, što za projektante može djelovati zbunjujuće. Ovim radom nastojalo se pomoći projektantima pri projektiranju i dimenzioniranu nasipa za obranu od poplava prema Eurokodu 7. Manjkavost EC7 u odnosu na nasipe za obranu od poplava uočila je i grupa za praćenje projekta pod nazivom „International Levee Handbook (ILH)“ (CIRIA C731, (2013.), te je za potrebe Ujedinjenog Kraljevstva i Irske izradila 2014. godine nacionalne upute pod nazivom “Primjena Eurokoda 7 na projektiranje nasipa za obranu od poplava” (dostupne na internetu). Tekst koji slijedi nije prijevod tog rada niti ga opisuje.Flood embankments are geotechnical facilities important for protection of human life and property. Eurocode 7: Geotechnical design - Part 1: General Rules; however, they are insufficiently taken into account. Design engineers are obliged to comply with the guidelines under this regulation, which are included in several EC7/1 chapters and may be confusing the engineers. The paper attempts to provide help to the engineers in the design and dimensioning of flood embankments according to Eurocod 7. The EC7 shortcomings with regard to flood protection dikes were noted by the group for the project monitoring – “International Levee Handbook (ILH)“ (CIRIA C731, (2013.). In 2014, they developed the national guidelines for the UK and Ireland – Application of Eurocode 7 to the design of flood embankments” (available on the internet). The text in this paper is not a translation or description of this document