Piura River and Its Sea Release

The Piura River with a basin area of 1,296 Km2, as well as it has yearly dry seasons, it has flood seasons with releases up to 4,000 m3 / s, surpassing the existing river training. The 2017 Niño Costero phenomena causes damages of around US $ 1,200 million.

Since the early XX century due to the cotton export boom, old landowners built some levees for land flood protection, while a new river channel was set further south, releasing water flows into Ramón lagoon complex, at 9.00 m asl. Once this is full impounded, water drains into Pampa de las Salinas; then water releases to the sea by the Bocana de Virrilá finally. This new river channel changes in 95 km from its old river mouth in the Pacific Ocean to the new one.

The old river course was shorter, this reached Bocana de San Pedro in just 32 km, after passing Sechura. This paper introduces to the changes required to return to the old river channel. This will involve to implement new levee embankments and changes in existing irrigation infrastructure for around of some US $ 200 million.

The current Piura river channel has a slope of 0.0002. The old one river channel had a slope of 0.0005. As a consequence the flow velocity was higher before supporting the removing of sediments to the ocean. Due to this reason adjacent areas to existing levees located in Ramon lagoon are sedimented, and they need to be raised now in order to avoid the aggradation phenomena from downstream to upstream, that means to the districts of Bajo Piura.

The aggressive sedimentation in Piura river channel can be just improved modifying the its existing river training channel by a new one releasing to the ocean near by Sechura, i.e. its old river training channel.