Picture added by GUILLARD Alain, owner of Gîte la Source, au pied des Alpes in Saint-Jean de Moirans

Paladru Lake is a natural lake (ice) of the pre-Alps. Today, the fifth largest natural lake in France, it was before the annexation of Savoy in 1860, the largest natural lake in France. It is often referred to as Blue Lake by its residents.

Paladru Lake is located in the department of Isere and more specifically in the hilly region of the lower Miocene-Dauphinee, called cold lands, roughly between the cities of Voiron and La Tour du Pin. It extends in a north-south axis of 5300 m, a width of 950 m. It has an average depth of 25 m, with a maximum of 35 m. Five municipalities sharing the coastline. It is in the direction of clockwise: Charavines (at the southern tip), Le Pin, Paladru (who gave his name to the northern tip), and Montferrat Bilieu. The beaches are located at both ends of the side edges have a steep slope.

The lake is the result of digging by the Rhone glacier on a deposit-dominated Miocene limestone of Lower Dauphiné. When removing when the warming Wurmian, 12 000 years ago, the dam of moraine Guillermet formed the lake. This origin is evident by the presence at the top of the surrounding hills, boulders, torn from the peaks of the Alps and abandoned at altitudes of 800 m during the withdrawal of the glacier. A witness called Peter impressive Beau Soleil or Sun Stone Free (6 m long and 4.50 m wide and 2 m high) is visible above Bilieu [1]. Note the trough-shaped valleys characteristic of the two adjacent to Lake Paladru the valley and the valley of Bourbre Ainan demonstrates the common origin of the Three-Vals.

His power is made by two streams: the Courbon side Montferrat and Chantabot side Le Pin, envoy of the pond du Vivier. A contribution from sources in-lake is evidenced by the significant difference between the total inflow and outflow. It gives rise to the Fure whose name evokes the violence of the original torrent. The Fure falls after a course of about twenty kilometers in the Isère Tullins after crossing Rives, a city famous in the Middle Ages to the quality of its swords. The valley of the Fure has experienced from the eighteenth to early twentieth destiny prosperous industrial (steel mills, paper mills). Outlet surface and a lock were built in 1869 to regulate the course of the dry season Fure and allow the operation of these plants.

(Source: Wikipedia)