Hidden beneath Velebit, river Krupa deserves much more attention than it has when we speak about it as the strongest tributary of Zrmanja. That is the reason why we speak about it right now. It is impossible to cross 50 meters along the canyon or the flow of the river, and you come to a view that is more beautiful than the previous one, and you thought that there isn't a prettier sight. In its short flow Krupa built around 19 falls (if we count the cascades Deveterac as falls), most of which belong among the most beautiful falls in Croatia. Krupa springs out near the hamlet Mandići from a typical karst spring. The spring part of its flow is being used by the inhabitants, and the river has been directed by ramps of stone in order to achieve a difference in altitude, necessary for running mills and watering fields. One of these mills, Urošev mlin from 1913. is still operating and working "full steam". Downstream from the mill the river runs through a narrow field and enters a short canyon, which goes to the Krupa Monastery. Fertile Monastery fields spread, after which there is again, a canyon through which the river runs to its mouth in Zrmanja. After Panića buk the river spreads and makes a little lake. Weedy harbors which appear along the river flow, are decorated with poplars and reed along the coast, as tall falls which slow down the river completely and make long lakes, give the canyon of Krupa its tame look which Zrmanja doesn't have.
A tributary Krnjeza springs out of Krnjeska glava (408 m). The spring is placed at the bottom of a 60m deep cave decorated with limestone curtains and stalactites and stalagmites. During the summer the first 400 meters of the flow, in a deep canyon, is dry, and then Krnjeza reveals its blue surface of ice cold crystal clear water and runs into Krupa. Downstream from the mouth of Krnjeza the canyon of Krupa suddenly opens and you can see a spacious weedy travertine barrier called Deveterac. Deveterac got its name after nine travertine cascades, which end with a 13 m tall fall over which there is Kudin Bridge. Kudin bridge has been built at the end of the 19th century. The master made 12 arches out of travertine blocks, and just as many pillars. Although the last two arches are damaged, Kudin bridge still stands despite time and high waters.
Then there is Panin buk, after which the canyon slowly falls in the area of Veliča luka, but only for a short while. Near the peak Punta, which stabbed the river deeply, forcing it to make a half of circle around it, the canyon again grows squeezing the river with a rock under Babin grad in a narrow passage in which there are three falls of which the last ones are 12 meter tall Babin fall and 8 meters tall Dragičevića buk. Beneath Dragičevića buk Krupa makes picturesque travertine thresholds, falls over at least two more falls and surrenders its waters to Zrmanja.
Zrmanja, though in some places of unstable flow, is by many, the most beautiful of the mentioned rivers. With its strength, and the strength of its tributaries, where we have to mention Krupa, Zrmanja found its way toward the sea for millenniums. Carving this hard limestone surface, it created one of the most monumental canyons and decorated it with numerous falls and travertine dams.
Lets go step by step, from the spring. Spring of Zrmanja is characteristic for its funnel shape on the bottom of which waters springs out abundantly, "boiling" among big moss covered rocks. When flowing along villages Bogunovići and Zrmanja Vrelo, the river formed a narrow bed whose bottom is covered with snow white stones. Through the narrow and long valley the river flows between fields to which it gives fertility, all the way to Kravlja draga. Here it enters a 200 meters deep canyon, through which it runs to the ruins of Keglevića gradine, where it again spreads through the valley of Mokro Polje. On the west end of Mokro Polje, large amounts of Zrmanja waters disappear beneath the ground toward the river Krka, and in the summer months this results in very low water levels, and even a dry bed of the river. We are not hiding our own surprise which we experienced looking for Zrmanja for the first time during the summer in Ervenik. We thought the dry bed was a macadam road. The bridge across the "macadam" solved the mystery of the missing river. The surface flow of the river, during the summer, begins at Crni bunar near the village Vujanići. The river goes on through a shallow canyon to Žegarsko polje. The flow is pretty wild here, during high waters, and cut with huge stone monoliths. On the exit from the canyon there are a few mills, which act as a dam covered with travertine. Although few are preserved, the fascinating roof on these mills is made of thin layers of stone plates.
Žegarsko field is on one side lined with the hills of Bukovica, and on the other side with river Zrmanja. The river has two stone bridges over it, one leads from Kaštela Žegarski to Nadvode, and the other to Krupa. Here Zrmanja receives its first tributaries, a creek from Mijića spring, and a temporary creek Suvaja with Suvaja spring and a spring in cave Velika Kusača, along with a creek with a spring in Milića cave. After Žegar Zrmanja gradually enters a deep canyon whose steep sides rise above 350 meters. This is probably the most beautiful part of the river. Under the spread out hips the river in some places formed beaches of pure white pebbles. On Panina hip, under which Zrmanja from the right receives its greatest tributary Krupa, you can see traces of an ancient fortress. Strengthened by Krupa, and mostly travertine, Zrmanja changes its face. 200 meters down from the mouth of Krupa, there is 11 meters high Visoki buk, the highest fall on river Zrmanja. The beauty which is attributed to the entire scenery, especially describes this travertine giant which will capture everyone's heart. The tragedy which happened in August 2001, when a huge travertine piece broke off Visoki buk and killed one person, warns us to be careful when found in the wilderness. On the part of the flow down from Visoki buk there is Obli kuk, completely round spikey rock on the left part of the river surrounded with water. An interesting sight is ten old travertine falls, 6-8 meters high, placed on the part from Visoki buk to the village Ogari. They also testify about natural changes which took part in ancient geological past.
At Ogari buk the canyon ends and the river flows along fields all the way to Muškovci fall and on to Berber buk. Downstream the river receives a tributary Dobarnica, and on the left bank there is a fort Klisina. From here the river spreads into the accumulation lake of the hydro electric power plant "Velebit". Underneath the dam the river flows through a mild canyon and down beneath the ruins of Stari Obrovac town it falls down Jankovića buk, in its last fall on Zrmanja. On Jankovića buk there are remains of old mills. This is a favorite vacation spot for visitors who come by tourist boats from Obrovac, but also those who come by speedboats from the summer spots on the shores of Novigrad sea, looking for refreshment in Zrmanja during summer heat. During low water levels beneath the fall itself you can feel strong sea influence. Underneath a thin layer of sweet water there is salty water, although there are 17 more kilometers of its flow to the mouth, and the water level changes depending on the tides. The city Obrovac is settled on the banks of the river, and the old and new parts of the city are connected with a bridge over which the road from Zagreb through Plitvice and to Zadar runs. On the left bank above the city there are ruins of a fortress of Kurjaković nobles (dukes), and a little further a vertical cliff Skočaj.

Down the stream from Obrovac, on the right bank, there is an old cemetary raised on the remains of a Benedictine monastery in Grkovac, and nearby is St. Nicholas chappel on the opposite left bank. The shallow waters near the banks are marked with red and green sea signs and are all in reed. From here the canyon grows deeper, and there is less vegetation on it. From the Fratri cliffs the river is much wider, and along the canyon there are steep sandbanks with rocks of limestone. This karst and heaps of stones would probably give a cold picture, if they were not colored with a spectrum of gentle gray, blue, yellow and red. Not far from the rocks called "Prince Mark's gate", there is on the left bank a fortress Pržunac whose tower can be clearly seen on top of the rock. The last 2 km of the flow, sandbanks replaced tall vertical cliffs which squeezed Zrmanja into a narrow passage right before its mouth in Novigrad sea. That passage along with the rock which peaks out of the sea on the mouth of the river, make a remarkable sight which stays remembered forever in the mind of every visitor of this beautiful river.
There's no doubt many conoisseurs of the natural heritage of Croatia will point out the Croatian karst as the most interesting, well hidden, attractive part of Croatia. From the experts point of view, who will point out karst as a habitat for many endemic species, space of most interesting geomorphologic and hidromorphologic phenomenons (caves, springs, falls and various trevertine shapes), or the tourists point of view, who come here because of preserved nature and peace and tranquility, everyone will agree that karst represents a unique and special part of Croatia.
Would this carved bare stone, with not much vegetation, draw our attention if it wasn't carved with green oasis' of karst rivers. Zrmanja with Krupa, Krka, Cetina and other rivers, left their trace in this area and gave life to many animal and floral species, but also to man.