Chapter 8: Anthropogenic Influence on Spit Dynamics at Various Timescales: Case Study in the Bay of Cadiz (Spain)

Abstract

Human interventions are one of the main drivers of coastal change in many areas, often generating undesired impacts like shoreline retreat. Sandspits are especially sensitive to anthropogenically-induced changes, especially those related to sediment supply. This work presents a case study of Valdelagrana spit in SW Spain, a sandbody where anthropogenic influence has been evident since Roman times. A variety of methods were applied to assess geomorphological and morphodynamic changes in the area at various timescales. Historical interventions involve mainly river course diversion, which caused important changes in sediment supply. More recently, coastal engineering structures and land reclamation deeply modified wave and current patterns in the area, triggering massive coastal erosion. As a consequence of this, the system has evolved from a drift-aligned spit to a swash-aligned barrier. This study provides insights into the consequences of human interventions at similar coastal settings.