Loire Valley (wine) a variety of limestone with excellent drainage that is known as tuffeau which is the same material used to build many of the famous Loire Valley Châteaux. The area around Chinon, Bourgueil and Saint-Nicolas-de-Bourgueil produces the majority of the Loire Valley's red wine based on the Cabernet franc grape—known in this areas as "Breton". The wines of the Chinon area are the softest and rich expression of the grape while the Bourgueil area produces more tannic and firm wines. The St-Nicolas-de-Bourgueil area produces the lightest colored wines. In the 19th century, the wines of the Chinon area were compared favorably
Loire of losing its status as the last wild river in France". The reason for this is its sheer length and possibility of extensive navigation, which severely limits the scope of river conservation. The Federation, a member of the IUCN since 1970, has been very important in the campaign to save the Loire river system from development. In 1986, the French government, the Loire-Brittany Water Agency and the EPALA settled an agreement on flood prevention and water storage programme in the basin, involving construction of four large dams, one on the Loire itself and three on the Allier and Cher. The