The estuary of the river Halaris is located about 2.5 km west - southwest of the village Armenistis, in Nas. It is a natural coastal wetland area of 19.9 acres. The torrent has a permanent flow almost all year-round with brackish water, it crosses the island in the direction from south to north and feeds mainly on small farmers scattered along the riverbed.
The wetland is fed by fresh water from the dam of the artificial Lake Pezi, located 4 km upstream of the estuary.
The wetland is located in an area desclared as a Site of Community Importance (code GR4120004), as a Special Protection Area (code GR4120005), as an Important Bird Area (code GR143) and A ' Archaeological zone (archaeological site under Raches), in the west where there is theTemple of Artemis.
The wetland has a rare biodiversity of flora and fauna, as well as populations of many protected and endemic species. Some of them are Galanthus ikariae (plant only found in Ikaria), while presenting rich vegetation of reeds and trees of various species dominated throughout its length and oleanders, osier and lentisk.
It also hosts a wide variety of birds, reptiles and amphibians, such as the Turkish lizard (rare protected species), the European eel (species that migrate from America for three years across the Atlantic ocean to reach the rivers of Ikaria), the otter (protected species), a rare species of freshwater crab and a benthic fish species of the genus Salaria, particularly important for the development of the zoogeographical freshwater fish fauna of Ikaria.
The canyon also has a special meaning for many protected species of permanent and migratory birds such as the Falcon, the Egret and the Bittern, which traverse hundreds of miles seeking rest and feed in the wetland environment.
The activities in the watershed are relatively mild, mainly grazing and cultivation. The major threats to the wetland resulting mainly from these two activities, are overgrazing and the intense irrigation of crops becomes uncontrollably by tires from the riverbed, thereby reducing the water level.
Lately, another intense threat to the habitat, is the increased tourism during the summer months, since the beach of Nas is one of the best beaches in Ikaria.