The Ullíbarri-Gamboa reservoir (in Basque and officially Uribarri Ganboako urtegia) is the largest reservoir in Álava province, Basque Country (Spain) with its 146 hm³ capacity and is part of a system of three reservoirs that fulfill a triple function: supplying Vitoria and Bilbao; regulate the flow of the Zadorra river; and serve as a recreation area, being a very popular place in summer. The reservoir dam is located between the towns of Ullíbarri and Arroyabe.
Before reaching the Garaio Provincial Park, there is a detour to the left that indicates the location of the Mendixur Ornithological Park, a wetland included in the Ramsar list. In it, you can enjoy the presence of a large number of birds from two observatories, many of them threatened.
The largest colony of imperial heron in the Basque Country is located in this area, as well as the only colonies of egrets and little egrets.
It is also an important wintering place, locating hundreds of ducks in eclipse, highlighting among them the contingent of red ducks.
In the reservoir, the islands of Alto Echániz, de los Caballos, Orenín and Zuaza are located.
How to get to? (Ullibarri-Gamboa town)
From San Sebastian 1 hr 12 min (89.3 km) via AP-8
From Vitoria 23 min (13.6 km) via A-3002
From Bilbao 58 min (74.0 km) via AP-68
From Madrid 3 hr 48 min (372 km) via A-1