These étangs are open deep water along one end, where there is an earth dam wall with a sluice to control overflow. The other end, where the water often enters via a small natural stream, forms a shallow tail of reedbeds and willow scrub. Beyond the reeds, in the water, are waterlilies and other truly aquatic plants. Bog plants growing along the tail of the étang include sedges, Clubrush, Bulrush, Branched Bur-reed, Yellow Iris and Marsh St Johns Wort.
Put together these étangs form wetland zones of similar significance to the better known Camargue or Baie de Somme. This is an ever changing landscape however. Every year in the late autumn many of the étangs are drained to harvest the fish. This practice also offers the opportunity to eradicate invasive species such as Water Primrose. Draining the lakes means that the rich mud, full of food for wading birds, is exposed.
The lakes are refilled either by water draining in off the surrounding land, or as part of a cascade of linked étangs which are emptied in sequence so all but the last is refilled by water coming down from the next. The fluctuating state of individual lakes and their close proximity to one another mean that the wildlife tends to migrate from one to another as conditions change.
|The well vegetated étang at the Maison du Parc, the Brenne.|
|L'Etang de la mer rouge in the Brenne, overflowing across the dam wall. Unusually, this very large étang is not controlled by a sluice, but the overflow is directed into a nearby small étang.|
|L'Etang vieux, well vegetated and run as a nature reserve in the Brenne.|
|The reedbed and willow scrub tail of l'Etang vieux in the Brenne.|
|Bird watching in the Brenne, at the étang by the Maison du Parc, in May.|