Plitvice Lakes National Park is one of the oldest and largest national parks in Croatia. In 1979, the park was added to the UNESCO World Heritage list because of its beautiful and unique group of tufa lakes, caves, and connected waterfalls.

The park was created in 1949 and is located in the mountainous limestone region of central Croatia, near the border with Bosnia and Herzegovina. A major road that runs north to south through the park connects the inland areas of Croatia to the Adriatic coastal region.

The protected area covers 296.85 km (114.61 square miles). About 90% of this area is in Lika-Senj County, and the remaining 10% is in Karlovac County.

Area

The lakes in the national park are arranged in a series of steps. From above, sixteen lakes can be seen. These lakes are famous for their unique colors, which include shades of blue, green, gray, and turquoise. The colors change often because of the amount of minerals and living things in the water, as well as the position of the sun.

Etymology

The name Plitvice was first written in a document in 1777 by Dominik Vukasović, the priest of Otočac. This name was given because of natural events that created the lakes. Nature formed shallow basins, called pličina or plitvak in Croatian. The word "plitko" means "shallow." For many years, water has changed the limestone and shaped the area's landscape. Travertine barriers formed, which slowed the water and helped it stay in place. These barriers keep getting taller over time.

Location

Plitvice Lakes National Park covers an area that spans two regions called counties in Croatia. The total area of the park is 296.85 km² (114.61 sq mi), with 90.7% located in Lika-Senj County and 9.3% in Karlovac County. Because of this, the national park is managed by the national government. The area covered by water in the park is approximately 2 km² (0.77 sq mi). The two largest lakes, Prošćansko jezero and Kozjak, make up about 80% of the total water area. These lakes are also the deepest, with depths of 37 meters (121 feet) and 47 meters (154 feet), respectively. No other lakes in the park are deeper than 25 meters (82 feet). The elevation difference between the first lake and the last lake in the park is 133 meters (436 feet).

Topography and geology

The amount of water available in an area is affected by the shape of the land. This water availability greatly influences the variety of plants and animals living there. The Plitvice Lakes are located near several mountains. On the western side of the national park, the Mala Kapela mountain forms a boundary. On the eastern side, the Lička Plješivica mountain borders the park and also marks the edge of Bosnia and Herzegovina. The park lies on the Plitvice plateau, which is surrounded by three mountains in the Dinaric Alps: Lička Plješivica (with its highest peak, Gola Plješevica, at 1,640 meters), Mala Kapela (with its highest peak, Seliški Vrh, at 1,280 meters), and Medveđak (at 884 meters). The forested slopes of these mountains act as natural water storage areas and provide homes for many animal species. The large difference in height between the southern mountains and the northern Korana River is an important factor in the area’s biodiversity. The total height difference within the park is 912 meters, with the highest point at Seliški Vrh (1,279 meters) and the lowest at the Korana River bridge (367 meters).

The Plitvice Lakes begin in the southern part of the park where the Bijela Rijeka ("White River") and Crna Rijeka ("Black River") meet. These rivers start south of the town of Plitvički Ljeskovac and join at a bridge in this village. From this point to the lakes, the water is called Matica, which means "water current" or "origin" in English. At Liman (also called Limun), a part of Prošćansko jezero, a small river flows into the lakes. This river is fed by springs that provide a steady water supply, though the amount can change. Occasionally, water from dry streams in the west also flows into Prošćansko jezero.

Tufa sediments have formed in sinkholes and low areas between the surrounding mountains since the Pleistocene era. The underground of the Plitvice Lakes can be divided into two main areas. The Upper Lakes in the south are mainly made of dolomite rock, while the Lower Lakes in the north are mostly made of limestone rock. Dolomite is slightly harder than limestone and allows less water to pass through. Limestone is more compact and solid but allows more water to flow through it.

Climate

The average yearly rainfall at Plitvice Lakes is 1,500 mm (59 in). The highest rainfall usually occurs during spring and autumn. The average air humidity is 81.8 percent. In January, the average temperature is 2.2 °C (36 °F). During July and August, temperatures rise to 17.4 °C (63 °F). The average temperature throughout the year is 7.9 °C (46 °F). Snow falls from November to March. The lakes are often frozen in December and January.

The dissolution and creation of rock

The lakes of Plitvice were formed over many years by natural processes involving the buildup of chalk, which is found in large amounts in the area’s karst rock. This buildup is known as tufa or travertine, which are also called sedra or tuf in Croatian, as well as other names like bigar or vapneni mačak.

Geologically, the features that shape the Plitvice Lakes are relatively new. The processes that dissolve and deposit limestone depend on specific climate conditions. These conditions began to exist only after the end of the last ice age, about 12,000 to 15,000 years ago, as shown by scientific studies of tufa.

In addition to weather and temperature, water quality and other natural factors are important in forming the lakes. As water moves through limestone underground, it dissolves chalk (calcite), which becomes concentrated in the water. This makes the water very mineral-rich, with high levels of calcium and magnesium-hydrogencarbonate.

The amount of calcium hydrogencarbonate in water depends on how much carbon dioxide is dissolved in the water. Generally, colder water holds more calcium hydrogencarbonate. Scientists have measured limestone dissolution rates of 0.01 to 4 millimeters per year. For example, rainwater could dissolve about 1 meter of limestone over 10,000 years.

Measurements of carbon dioxide in the water show that its levels match the ongoing buildup of tufa in the Plitvice Lakes area. At the springs, carbon dioxide levels are about twenty times higher than in the atmosphere. As water flows, carbon dioxide levels decrease. For example, the Plitvica River loses up to 97% of its original carbon dioxide along its path.

The area where tufa forms is called a precipitation zone. Along the Korana River, tufa forms only in the first 10 to 15 kilometers, even though conditions further down the river might seem suitable. At the bottom of Lake Kozjak, scientists have found that tufa builds up at a rate of 0.8 millimeters per year over the past 3,000 years. Each year, barriers in the lake grow up to 13 millimeters in height. Tufa formation outpaces erosion, which would otherwise destroy the lake’s delicate barriers. Scientists estimate that tufa at the lake’s bottom is at least 6,000 to 7,000 years old.

Calcium carbonate does not immediately form tufa at the springs of rivers flowing into the Plitvice Lakes. For tufa to form, water must reach a certain level of mineral saturation. At the springs, this level is about 1. For tufa to form, the saturation level must be higher than 3, and the water’s pH must be above 8.0 (slightly alkaline).

Over time, older barriers in the lakes can be covered by rising water levels as newer barriers grow. About 400 years ago, there were two lakes where Kozjak Lake is today. In the lowest part of the lake, near Matijaševića draga, there is an underwater barrier 40 meters high that extends 4 meters below the water’s surface. This barrier likely formed a waterfall in the past. However, the tufa barrier at the Kozjak bridges grew faster, merging the two lakes into one. This is why the deepest parts of Kozjak Lake are in its lower basin, north of the small island.

Mosses, algae, and water plants are important in forming the unique landscape of the Plitvice Lakes and their tufa barriers. Until the 21st century, scientists, including botanist Ivo Pevalek, believed that plants removed carbon dioxide from water for photosynthesis and released oxygen, which helped tufa form. Recent studies show that plants are not the main cause of tufa formation but do help indirectly. For tufa to form, water must slow down, mix with air, and spray. Mosses on the lakes’ waterfalls provide surfaces for tufa to build up. Different types of plants can create different kinds of tufa. Photosynthesis by algae and mosses helps tufa form by removing carbon dioxide. Young moss shoots are green and soft, with little tufa, while older shoots are covered in a thin, yellow layer of hardened tufa. Mosses not only help create tufa barriers but also become part of them. Over time, the tufa forms caves and crags, and older tufa contains fossils of algae and mosses. This type of rock, common in the Plitvice Lakes, is called "phytogeneous tufa."

During the 20th century, uncontrolled tourism and pollution from hotel waste and farming in the surrounding area harmed the lakes. This led to increased eutrophication, meaning more organic substances in the water. To protect the lakes and allow tufa to form naturally, it is essential to limit harmful human activities. Since 2006, swimming in the lakes has been strictly forbidden.

Biodiversity

Scientists have found 109 species in the national park area, and 75 of these are found only in this region. Many of the plants and animals here are protected by law. There are 55 different types of orchids in the park. The variety of plants creates colorful changes in appearance throughout the year. The national park covers 29,842 hectares. Of this area, about 22,308 hectares are forests (74.75 percent), 6,957 hectares are meadows (23.31 percent), and 217 hectares are water areas (0.72 percent). A special part of the park is Čorkova uvala, a 79.50-hectare untouched forest in the northwestern section. Some of the beech and fir trees in this area are up to 700 years old.

The park is home to several animals, including the European brown bear, grey wolf, Eurasian eagle owl, Eurasian lynx, European wildcat, and western capercaillie.

The park has about 50 species of mammals. Scientists have discovered 321 different types of butterflies and moths, with 76 being day-flying butterflies and 245 being night-flying moths. They believe that only about 40 percent of all butterfly and moth species in the area have been identified. Twelve types of amphibians and several reptiles live here, including the viviparous lizard (Lacerta vivipara), the European green lizard (Lacerta viridis), the dice snake (Natrix tessellata), Vipera berus, Vipera ammodytes, and the European pond turtle (Emys orbicularis).

The Plitvice Lakes are the third most diverse in bird species among Croatian national parks. About 157 bird species have been recorded, with 70 of them nesting in the area. Recent studies show that around 20 bat species live here, including rare species in the Plecotus genus.

Brown trout (Salmo trutta fario and Salmo trutta lacustris) are native fish species found in the lakes. S. t. fario is mostly found in the Upper Lakes, while S. t. lacustris is mainly found in Lake Kozjak. These fish developed separately in different lakes due to their unique living conditions.

History

During the 6th century, the Avars arrived in this region along with the Croats. The Croats later resisted Avar control and settled permanently in the area. In medieval times, attacks by Mongols were a constant danger to the people living there. Under Croat rule, especially during the leadership of noble families like the Zrinski and Frankopan, the region experienced economic growth. A monastery was built on the remains of an ancient settlement once inhabited by the Japods and Romans. This monastery may have belonged to the Order of Saint Paul the First Hermit or the Knights Templars. Today, only the ruins of the building, called "gradina" in Croatian, remain. The foundation was made of travertine rock.

At the time, the region was home to native Croats who also served in the Austrian military. Many Central Europeans and Serb Orthodox refugees fleeing Ottoman rule moved to the area. These refugees were given land in exchange for military service. People living in the military frontier, including frontiersmen, were responsible for protecting the region from unrest and destruction. The area was once called "hortus diabolus," or the "garden of the devil."

In 1861, a building for travelers was constructed at Velika Poljana. The local people called it the "Emperor's house" because military officers from the empire stayed there. For the visit of Crown Princess Stéphanie of Belgium in 1888, the Plitvice Lakes and surrounding areas were prepared for tourism for the first time. Two paths near the lakes are named after the daughters of Emperor Franz Joseph: "Štefanijin put" (Stephanie's Path) and "Dorotejin put" (Dorothea's Path). In 1893, Gustav Janeček, a Czech man from Zagreb, built a restaurant and accommodation at the lakes. He also founded the Society for the Preservation of the Plitvice Lakes, which aimed to protect the area from harm. The society built a hotel at the lakes. In 1898, a waterfall was named after Milka Ternina, a Croatian opera singer who donated money to help preserve the park.

During the 1940s, important events took place at the Plitvice Lakes. In 1940, the first secret meeting of the League of Communists of Croatia occurred there. In 1943, a key meeting of the National Anti-Fascist Council of the People's Liberation of Croatia (ZAVNOH) was held at the lakes. This group was the main leadership of Croatia's anti-fascist movement during World War II. Rade Končar, a former leader of Croatia's Communist Party, was born near the lakes in 1911.

Between 1962 and 1968, films based on Karl May novels were filmed at the Plitvice Lakes, mostly by German-French-Yugoslav teams. The most famous film, Treasure of Silver Lake, used parts of the national park as a setting.

In the 1970s, detailed maps of the park were created. In 1979, the park was added to the UNESCO World Natural Heritage List because of its natural beauty and the unique formation of travertine rock.

During the 1980s, tourism in Yugoslavia grew rapidly, and the Plitvice Lakes became one of the country's most popular attractions. However, the 1990s brought challenges. In March 1991, the first armed conflict of the Croatian War of Independence, known as the "Plitvice Bloody Easter," occurred at the lakes. The area was later controlled by Serb rebels and the Yugoslav army, which caused damage and led to the forced removal of Croats from the region.

Today, scientists continue to study the park. The park's management is working to improve protection efforts, including replacing wooden bridges with floating ones to prevent damage to the fragile travertine rock.

The Plitvice Lakes are one of Croatia's most visited attractions. Their natural and cultural value supports the local economy, with about 1 million visitors each year. However, pollution from tourism and illegal construction has made the lake water unsafe to drink. In 2018, UNESCO warned that the park might lose its World Heritage status. To address this, the park limited daily visitors to 12,000 in the summer and 600 per entrance per hour.

In 2024, the park director stated that the main limit on visitors is the number allowed daily in the summer. The park receives about 1.5 million visitors each year, which is about 10% of all visitors to Croatia. The highest number of visitors was recorded in August, while May and September had more visitors than June, showing a positive trend.

Local customs and traditions

Keeping old customs and traditions is very important for the people who live in the area. The local culture is also an important part of tourism in the region. In terms of architecture, the area of Lika is known for its small wooden houses with roofs made of rye straw or shingles. Many aspects of the old way of life are shown in the local costumes. These costumes provide information about where people are from or their social positions. During French rule, men were allowed to wear their traditional costumes while serving in the military.

Waterfalls

Waterfalls in the Plitvice area have been given the following names:

• Jarkuše, located between Ciginovac Lake and Okrugljak Lake
• Labudovački slap, located between Prošćansko Jezero and Ciginovac Lake
• Labudovac, located between Labudovac Lake and Batinovac Lake
• Mali Prštavac, Veliki Prštavac, Stari, and Veliki Galovački buk (20 m/66 ft), all located between Galovac and Milino and Gradinsko Jezero
• Milka Trnina Waterfall, located between Milanovac and Gavanovac
• Sastavci, located between Novakovića Brod and the Plitvica and Korana rivers
• Plitvica or Veliki slap, meaning "Big Waterfall" (78 m/256 ft), located on the Plitvica stream
• Four Korana waterfalls, located on the Korana River downstream