Agriculture, Ecosystems and Environment, 33 ( 1990 ) 181-186 181 Elsevier Science Publishers B.V., Amsterdam Traditional montane irrigation systems in modern Europe: an example from Valais, Switzerland A.T. Grove ~ and J.M. Grove 2 iDowning College and 2Girton College, Cambridge (U.K.) (Accepted for publication 9 June 1989 ) ABSTRACT Grove, A.T. and Grove, J.M., 1990. Traditional montane irrigation systems in modem Europe: an example from Valais, Switzerland. Agric. Ecosystems Environ., 33:181-180. In many mountainous regions around the Mediterranean, ancient irrigation systems lead water from high level sources to meadows and cropland. Some of these systems have remained in use over a period of 600 years or more. They originated in rural societies and were operated by these local societies. They were always vulnerable to natural hazards. Now, they are under threat from social changes and also from large-scale engineering works. In the Swiss Valais, to which attention is directed here, many of the "bisse" systems are still highly valued and in operation and, though modernized, remain under the control of the communes. This example of adaptation to modem circumstances might well be followed elsewhere. INTRODUCTION In the mountain regions of southern Europe, both pastureland and crop- land suffer from lack of water on account of the high insolation and lack of rain in summer. In medieval times irrigation systems were established which led water from glaciers, snowfields and springs high up in the mountains, by skillfully constructed channels along steep precipices and across gorges, to lower slopes where it was needed for pastures, cereals and vineyards. Amongst the earliest of such systems are those on the Guadalfeo fiver south of the Sierra Nevada (Brunhes, 1902; Mignon, 1981 ); others are in the Pyrenees, the Mas- sif Central and the Alps (Carder, 1932; Bums, 1963 ). If irrigation water is available then it is worthwhile to terrace slopes and cultivate land that would otherwise be unproductive. The land can support a local farming population and the scenery is attractiveto tourists and holiday- makers. Since the 1950s, with the greatly increased opportunities for employ- ment in towns, factories and hotels outside the mountains, especially in towns 0167-8809/90/$03.50 © 1990 -- Elsevier Science Publishers B.V.