4 research outputs found
Numerical model of stratified flow ā case study of the Neretva riverbed salination (2004)
U podruÄju donje Neretve postoje dva prirodna pravca prodora slane morske vode: prvi, kroz korito rijeke Neretve te drugi, kroz duboke podzemne slojeve. U radu je opisan numeriÄki model uslojenog teÄenja te je primijenjen za proraÄun zaslanjivanja rijeke Neretve kroz prvi pravac prodora. Kalibracija modela napravljena je na temelju mjerenja iz 2004. godine. UtvrÄeno je da se slana voda pojavljuje u MetkoviÄu pri protocima slatke vode manjim od 180 m3/s, dok je za protoke veÄe od 500 m3/s slana voda potpuno istisnuta iz korita rijeke.Two natural directions of saline sea water intrusion have been registered in the lower reaches of the Neretva River: the first direction of intrusion is through the Neretva riverbed, and the second one through deeper underground layers. The numerical model of stratified flow is described, and its application in the analysis of the Neretva River salination via the first direction of intrusion is presented. The model is calibrated based on measurements conducted in 2004. It was established that saline water appears in MetkoviÄ at fresh water flow rates of less than 180 m3/s, while saline water is fully blocked out from the riverbed when water flow exceeds 500 m3/s
Hydrodynamic wave analysis as basis for sustainable beach design
UreÄivanje i stabilizacija pomiÄnih dijelova obalne crte složena je zadaÄa jer je u takvim priobalnim podruÄjima složena interakcija mora i obale. Ako se analiziraju plaže, bilo prirodne bilo novoizgraÄene, zadaÄa je joÅ” zahtjevnija buduÄi da one služe za odmor i rekreaciju te je nužno i odgovarajuÄe održavanje. Za pravilno oblikovanje i održavanje plaža primjenjuje se numeriÄko modeliranje. U radu je primjenom modela CGWAVE provedena optimalizacija oblika plaže od zrnatih materijala u svrhu osiguranja njezine održivosti.The regulation and stabilization of movable parts of shoreline is a complex task, as the sea and shore interaction is quite complex is such coastal areas. If the analysis concerns beaches, either natural or newly built ones, the task becomes even more complex as they are used for rest and recreation, and so an appropriate maintenance must also be provided. Numerical modelling is conducted to enable proper shaping and maintenance of beaches. In this paper, the CGWAVE model is used to optimize a beach made of granular material, in order to ensure its sustainability
Influence of breakwater on the wave field in Makarska port
U radu je prikazana analiza valnog polja u luci Makarska numeriÄkim modeliranjem postojeÄeg stanja (bez lukobrana) i varijantnih rjeÅ”enja planiranog lukobrana. Analizirana je uÄinkovitost lukobrana pri djelovanju valova iz smjerova W-pulenat, SW-lebiÄ, S-oÅ”tro, SSE-jugo. Temeljem usporedbe rezultata numeriÄkih simulacija promjene valnog polja, predloženo je optimalno rjeÅ”enje lukobrana za zaÅ”titu akvatorija luke od valova. Analiza je provedena numeriÄkim modelom Artemis-Telemac.The authors present an analysis of wave field in Makarska Port based on numerical modelling of the existing situation (without breakwater), and according to alternative solutions for the planned breakwater. The performance of breakwater with respect to wave action from W-pulenat, SW-lebiÄ, S- oÅ”tro, and SSE-jugo, is analyzed. Based on comparison of results obtained by numerical simulation of changes in wave field, a breakwater solution ensuring optimum protection of port area against wave action is recommended. The analysis is based on the Artemis-Telemac numerical model
Ingresija hidromeduse Neotima lucullana (della chiaje, 1822) u ekosustavu estuarija rijeke Neretve (jugoistoÄni Jadran, Hrvatska)
Hydromedusa Neotima lucullana is an endemic species of the Mediterranean Sea. In this study
we document the first numerous and permanent occurrence of N. lucullana in the estuary of the
Neretva River, an unusual habitat for this typical marine species. We provide COI barcode sequence
of this species, which is also first genetic sequence ever published of N. lucullana. Weekly data on the
occurrence and abundance of N. lucullana were obtained from reports and records of autonomous
divers and local fishermen in the area from Opuzen to MetkoviÄ from mid-June to the end of October
2021. The individuals were always located in the layer above the bottom with salinity between 35.2
and 38.2. The diameters of the jellyfish bells ranged from 15 mm to 72 mm, most of them between
40 mm and 58 mm. Differential development of the gonads was observed in all specimens larger
than 25 mm. In mid-June, the specimens were common but solitary. A week later, the jellyfish
were more frequent and in smaller aggregations. From late June to mid-September, the jellyfish
were constantly observed in larger aggregations. Toward the autumn, the number of individuals
gradually decreased, and by the last week of October, only single individuals were observed. Our
results indicate significant changes in the ecosystem of the Neretva estuary and confirm the observed
composition of zooplankton communities dominated by marine species in summer and autumn.Hidromeduza Neotima lucullana je endemska vrsta Sredozemnog mora. Ovim istraživanjem
dokumentiramo prve zapise o brojnoj i dugotrajnoj pojavi meduze N. lucullana u estuariju rijeke
Neretve, neobiÄnom staniÅ”tu za ovu tipiÄno morsku vrstu. U sklopu ovog istraživanja dobivena
je sekvenca podjedinice i citokrom oksidaze (COI), Å”to je ujedno i prva genetiÄka sekvenca ikad
objavljena vrste N. lucullana. Tjedni podaci o pojavi i brojnosti N. lucullana dobiveni su na osnovi
izvjeÅ”taja i zapisa autonomnih ronilaca i lokalnih ribara na podruÄju od Opuzena do MetkoviÄa od
sredine lipnja do kraja listopada 2021. Jedinke meduza su uvijek bile u sloju iznad dna unutar vrijednosti saliniteta izmeÄu 35,2 i 38,2. Promjer zvona meduza kretao se od 15 mm do 72 mm, glavnina izmeÄu 40 mm i 58 mm. Diferencijalni razvoj spolnih žlijezda uoÄen je kod svih primjeraka veÄih od
25 mm. Sredinom lipnja jedinke su bile uobiÄajene, ali prisutne pojedinaÄno. Tjedan dana kasnije,
meduze su bile Äesto viÄene i u manjim skupinama. Od kraja lipnja do sredine rujna, meduze su bile
prisutne u veÄim agregacijama. Broj jedinki postupno se smanjivao prema jeseni i samo pojedinaÄni primjerci bili su uoÄeni tijekom posljednjeg tjedna listopada. NaÅ”i rezultati ukazuju na znatne promjene ekosustava donjeg toka rijeke Neretve Å”to potvrÄuje zabilježen sastav zooplanktonskih
zajednica u kojima dominiraju morske vrste tijekom ljeti i jeseni