El Niño phenomenon in the lower Piura valley: Linkage between river floods, infrastructure and population displacement to achieve integral management plans.

Abstract:

The El Niño Phenomenon (FEN) events produced in 1983, 1998 and 2017 have caused economical, social, environmental impacts in the Piura region. The hydraulic infrastructure for flood protection built in the Lower Piura valley has been repeatedly affected, destroying both agricultural and urban areas. This research analyses the relationship between the land occupation and the vulnerability of human settlements in risk areas (i.e. riverine floodplain) after the El Niño occurrence. Moreover, to irrigate the productive areas and protect the population against floods, the Piura river stream has been disturbed by constant dredging over the years. As a consequence, sedimentation occurred along the river generating changes in the slope that have resulted in frequent overflows on the left bank. This process caused significant damage to the city of Piura: 93 thousand victims, 336 thousand people affected and 18 deads.

The analysis shows a direct relationship between the affectation of the defense levees and the temporal and permanent displacements of the most affected population settlements. Given this, the importance of adequate disaster risk management across the board in the development of land use plans in vulnerable coastal areas is evident. Therefore, solutions do not necessarily include improving the flood protection infrastructure, but rather understanding the basin under a multidisciplinary and integral framework. Hence, the river master plans are an alternative; however, they must go beyond the management of water resources and include a basin-wide overview (including the social, productive, economic and territorial perspective) to improve the use of space and resources for a sustainable development.