A river that flows between some of the larger rivers of Greece, connects the mountains of Epirus with the plains of Grevena and forms landscapes of great aesthetic value. Venetikos river is the largest tributary of the big Aliakmonas river and flows entirely in the prefecture of Grevena. It stems in the east of the prefecture from two streams that descend, one from the south-eastern slopes of Vasilitsa mountain and the north-east of Avgo mountain and the other from the south of the Taliaros hills. The two streams (Aspropotamos from the west and Dotsikiotiko from the north) meet in the gorge of Portitsa, between the villages Spilaio and Parorio, forming the original part of Venetikos. Just before their meeting the northern branch of the river is called Velonias. Venetikos then moves from west to east at a distance of 46 km. It flows south of Orliakas mountain and continues south of the city of Grevena, where at the main road connecting Grevena and Kalambaka flows between vertical rocks, the famous “Gates of Venetikos”. A few kilometres east, near the village of Agapi, Venetikos ends into Aliakmonas river. In its path, Venetikos accepts the waters of dozens of streams and little rivers, such as Smixiotiko, Stavropotamos, Tranos Lakkos, Sarganaiko, Agiouaras, Vathylakkos, Kerasia Lakkos, Paliokastro, Dyo Dendra, Kerasia and Kryoneri. The areas around Venetikos are characterised by molasse formations and alluvial deposits. Throughout its route, the river forms many different habitats in one of the most wild and pristine areas of Greece. Large canyons, small valleys and dense riparian forests alternate in a unique route that can be experienced through rafting. Venetikos and its streams are famous for the dozens of old mills and the magnificent medieval stone arched bridges, such as the bridges of Portitsa, Aziz Aga, Spanos, Stavropotamos, Kalogiros and Kagelia.
The riparian forests of Venetikos consist of common alders, willows, narrow-leafed ashes and oriental plane trees, while throughout its length it moves between wooded slopes with firs and pines giving their place to various oaks. Around the river one can discover many important species of plants. Most important of these are bulrush Typha shuttleworthii, Colchicum autumnale, Galanthus reginae-olgae subsp. vernalis, Dianthus deltoides subsp. degenii, lizard orchid Himantoglossum jankae, Actaea spicata, Betonica scardica, Anthericum liliago and Tragopogon balcanicus. Other plants in the region are Crocus nivalis, Petasites hybridus, Digitalis grandiflora, Scutellaria columnae subsp. columnae, Iris sintenisii subsp. sintenisii, Viscaria atropurpurea, Primula vulgaris subsp. vulgaris, Agrimonia eupatoria subsp. eupatoria, Armeria canescens, Salvia sclarea, Delphinium fissum subsp. fissum, Allium amethystinum, Lythrum salicaria, Knautia orientalis, Lomelosia argentea, Centaurea grisebachii subsp. confusa, Centaurea pelia, Rosa gallica, Geranium macrostylum and Verbascum graecum. The surrounding areas are full with orchids, such as Cephalanthera damasonium, Cephalanthera longifolia, Cephalanthera rubra, Epipactis palustris, Epipactis helleborine, Epipactis microphylla, Neottia nidus-avis, Neottia ovata, Limodorum abortivum, Platanthera chlorantha, Dactylorhiza iberica, Dactylorhiza romana, Dactylorhiza saccifera, Anacamptis palustris, Anacamptis laxiflora, Anacamptis morio, Neotinea tridentata, Orchis purpurea, Orchis pauciflora, Orchis provincialis, Ophrys apifera, Ophrys oestifera, Ophrys reinhardiorum, Ophrys helenae, Ophrys hystera, Ophrys mammosa, Ophrys epirotica, Ophrys grammica, Ophrys hebes and Ophrys zeusii.
The birdlife is rich and includes species found in various habitats. Permanent is the presence of grey wagtails and dippers, while often appear species that live in rivers like grey herons, great egrets, little egrets, cormorants, kingfishers, snipes and sandpipers. Until a few years ago close to the river lived griffon vultures and Egyptian vultures. The birds of prey here include lesser spotted eagles, short-toed eagles, booted eagles, black kites, honey buzzards, common buzzards, sparrowhawks, levant sparrowhawks, goshawks, kestrels, lesser kestrels, hobbies, peregrines and rare lanner falcons. From the nocturnal predators in the area live eagle owls, tawny owls, barn owls and little owls. The avifauna is supplemented with species, such as quails, woodcocks, woodpigeons, stock doves, turtle doves, cuckoos, nightjars, alpine swifts, bee-eaters, rollers, green woodpeckers, middle spotted woodpeckers, lesser spotted woodpeckers, skylarks, woodlarks, crag martins, swallows, red-rumped swallows, house martins, water pipits, tree pipits, wrens, dunnocks, robins, nightingales, black redstarts, northern wheatears, stonechats, blue rock thrushes, song thrushes, mistle thrushes, blackcaps, orphean warblers, whitethroats, lesser whitethroats, subalpine warblers, moustached warblers, Cetti’s warblers, reed warblers, great reed warblers, Bonelli’s warblers, firecrests, goldcrests, spotted flycatchers, semicollared flycatchers, great tits, coal tits, willow tits, marsh tits, sombre tits, penduline tits, wood nuthatches, treecreepers, red-backed shrikes, lesser grey shrikes, jays, jackdaws, rooks, ravens, golden orioles, tree sparrows, linnets, goldfinches, siskins, serins, hawfinches, cirl buntings, rock buntings and corn buntings.
From amphibians in the region live fire salamanders, greek newts, macedonian crested newts, common toads, green toads, yellow-bellied toads, tree frogs, balkan frogs, agile frogs and greek frogs. Herpetofauna includes species such as, greek pond turtles, Hermann’s tortoises, greek tortoises, greek slow worms, glass lizards, balkan green lizards, common green lizards, common wall lizards, balkan wall lizards, worm snakes, smooth snakes, large whip snakes, four-lined snakes, levant montpellier snakes, grass snakes, dice snakes, Dahl’s whip snakes, cat snakes, aesculapian snakes, leopard snakes and nose-horned vipers. Large mammals such as brown bears and wolves appear in the dense forests surrounding Venetikos, while healthy populations of otters live along the river. Other mammals here are wild cats, foxes, wild boars, weasels, pine martens, badgers, hares, hedgehogs, forest dormouses, edible dormouses and red squirrels.
The ichthyofauna of the river includes many species of rare fish. Some of them are the European spirlin (Alburnoides bipunctatus), the large spot barbel (Barbus balcanicus), the stone loach (Barbatula barbatula), the Vardar nase (Chondrostoma vardarense), the Vardar spined loach (Cobitis vardarensis), the pike (Esox lucius), the Aegean gudgeon (Gobio bulgaricus), the Macedonian moranec (Pachychilon macedonicum), the Balkan golden loach (Sabanejewia balcanica), the freshwater blenny (Salaria fluviatilis), the topmouth gudgeon (Pseudorasbora parva), the dark vimba (Vimba melanops), the common roach (Rutilus rutilus), the Thessaly bleak (Alburnus thesalicus), the West Balkan trout (Salmo farioides) and the Pelagonian trout (Salmo pelagonicus). In many spots, the river is very calm and clear and so, during summer, one can swim with a dive mask and observe these species in their habitat.