Domains of spit evolution in the Goro area, Po Delta, Italy Umberto Simeoni a, ⁎ , Giorgio Fontolan b , Umberto Tessari a , Corinne Corbau a a Dipartimento di Scienze della Terra, Università degli Studi di Ferrara, Via G. Saragat, 1- 44100 Ferrara, Italy b Dipartimento di Scienze Geologiche, Ambientali e Marine, Università degli Studi di Trieste, via E. Weiss 2 - 34127 Trieste, Italy Received 27 April 2005; received in revised form 6 September 2006; accepted 6 September 2006 Available online 27 October 2006 Abstract Goro lagoon was formed during the 19th century in the southern part of the Po Delta. Its origin is related to the growth of a spit system, which progressively occluded the southernmost interdistributary bay from the sea. The development of the spits is due to the morphological prominence of the Po Delta which causes a divergent littoral drift, enhanced by wave refraction over the delta front. During the last century the spit was abandoned, destroyed, and re-constructed several times because of the development of newer spits seawards. Using historical maps and aerial photographs, three different periods are recognised, featuring distinctive spit growth styles: parallel, fan-shaped and branched. The different domains of spit evolution are related to several factors, mainly to the mutual influence of sediment discharge, sand mining along the Po river, wave action over the delta front, human-induced subsidence and direct human interventions along the spits and for flood-control. © 2006 Elsevier B.V. All rights reserved. Keywords: Morphological evolution; Spit; Lagoon; Subsidence; River discharges; Adriatic Sea 1. Introduction Goro Lagoon is associated with the Po Delta system (Fig. 1), which is characterised by six main river distributaries: Po di Levante, di Maistra, di Pila, di Tolle, di Donzella and di Goro. The Goro Lagoon developed south-westward of this latter distributary. Its surface is about 2600 ha and its average depth about 1.2–1.5 m. According to the Ramsar Convention in 1971, the Goro Lagoon was classified as a wetland of international importance. It became a natural reserve in 1982 and, since 1988, it has been included in the Regional Park of the Po Delta. All these aspects, which enhance the environmental value, coexist with important economic activities. The clam fishery employs around 1000 people and is worth 50 Million Euros/year (Simeoni, 2003). In the last decade, the frequency of eutrophication and anoxic phenomena led to negative economic consequences. The fishery crisis gave rise to a new intervention policy aimed at improving the hydraulic exchanges between the lagoon and the adjacent river and sea in order to enhance lagoon circulation. During the last century, human intervention was powerful and incisive, particularly along the spit (Scanno di Goro), and unavoidably compromised the normal evolution of the lagoon. The subsequent lagoon evolutionary trend represents one of the last direct responses to the human action along the Goro coast. It is easy to correlate the change in geo-environmental characteristics of the Goro Lagoon with the territory modifications and human-induced transformations that mainly occurred during the 20th century. In this context, Geomorphology 86 (2007) 332 – 348 www.elsevier.com/locate/geomorph ⁎ Corresponding author. E-mail address: g23@unife.it (U. Simeoni). 0169-555X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.geomorph.2006.09.006