The Maggia river rises from the Pizzo Cristallina and extends over 56 kilometres through the Sambuco Valley, the Lavizzara Valley and the Maggia Valley.

View of the Maggia estuary North-South, on the first picture above left, the old airfield is marked with a box. Copyright: Zeitschrift für Landschaftsarchitektur (1985)

The estuary forms a wide delta between Ascona and Locarno. This delta opens into Lake Maggiore and is constantly expanding. On the picture situated on the left, there can be seen the development of the Maggia estuary from 1865 up to nowadays.

The blue box on the first picture corresponds to the placement of the former airfield in Ascona (see our article on Herbert von Karajan). 

The overall catchment area of the Maggia river is about 930 square kilometres with several inflows, the most important of which are Melezza, Rovana and Bavona.

Long dry periods and heavy rains characterise the specific climate of this Insubrica region. In times, heavy rains swelled the river very strong, the ratio of minimum and maximum amount of water could range of 1/7000. 

The sediments carried from the river to the valley are also considerable, this is why the estuary is growing in size. The strong initial slope of the river and the gravel composition of the river bed, combined with the sparse vegetation, have created a permanent erosion effect, which is also reinforced by the river-stream. The Maggia estuary is very large, compared to the rest of the Insubrica rivers.

About ten hectares of the Maggia estuary are shared with the municipalities of Locarno (93%) and Ascona (7%). It is a beautiful wetland and a river basin, which is periodically submerged by floods of Lago Maggiore (with its main tributary, the Ticino river) and by the floods of the Maggia river. The establishment of the reserve dates back to 1985. Since 1990, it has been included among the protected areas of the Canton Ticino, and this estuary is one of the most important of the estuaries in the Insubrica region. 

The land of the reserve belongs largely to the Società Terreni alla Maggia SA. Only a small part belongs to the public domain. Terreni alla Maggia as well as the nearby luxury hotel «Castello del Sole» are wholly owned by two families Bührle and Anda, the heirs of the Oerlikon Bührle Group. The Oerlikon Bührle family deserves a specific dedication on our Web site, but it is possible to anticipate few major aspects right now. 

Oerlikon Bührle acquired in 1923 a factory in Germany, entering thus the anti-aircraft defence business in 1924. In 1936, he founded a purely anti-aircraft development company, called Contraves (contra aves from the Latin for “against birds”). In 1989, the Werkzeugmaschinenfabrik Oerlikon-Bührle and Contraves merged together, forming the Oerlikon-Contraves Group, later renamed to Oerlikon Contraves Defence. Oerlikon Contraves was purchased by Rheinmetall, a German armament manufacturer in 1999 and renamed Rheinmetall Air Defence AG on 1 January 2009. On the other side, Oerlikon Bührle Group renamed itself in 2000 as Unaxis, then from 2006 as OC Oerlikon Corporation AG, which is today controlled by a company Sonova that belongs to Russian businessman, with Ukrainan origins, Viktor Vekselberg (1957 – ).


  • P. Bürgi, L. Paolo, G. Cotti, P. Vanossi, Delta della Maggia = Maggia estuary (English translated), Zeitschrift für Landschaftsarchitektur 24 (1985), pages 28-32


  • There are many possibilities to visit the Maggia estuary. The most scenic is from the left bank (Ascona side). You can park the car at Terreni alla Maggia and walk alongside the canalisation dam. The estuary changes its shape according to the water level. Definitely, it is the most interesting access to it during dry periods.