Impacts of El Niño on the climate-food nexus: understanding the controls and geomorphic implications of flooding on food production in northern Peru

Overview

Between January and April 2017 El Niño Costero (coastal El Niño) generated catastrophic floods in the Piura region of northern Peru impacting over 1.7 million people resulting in 178 deaths, 77,300 homes destroyed or damaged and the displacement of 10,000 people (USAID, 2017). Risk to life, infrastructure and property is considerably enhanced when flood waters are charged with sediment and floating debris. Enhanced stream powers during high magnitude floods drive erosion and deposition of sediment, which in turn bring about significant changes in channel cross-sectional geometry and major river channel avulsions into populated areas. Increased supply of sediment to fluvial systems through natural or anthropogenic processes can also have a major impact on downstream river channel dynamics resulting in localised aggradation and the downstream passage of sediment waves. Such hydro-geomorphological activity poses a major hazard to population, food production and infrastructure in both developed and developing nations.

Methodology

This project takes a mixed-methods approach by starting with a systematic examination of the impacts of the 2017 El Niño Costero floods in terms of understanding geomorphic change and it’s implications for agri- and aqua-cultural food production in northern Peru. The student will used remote sensing (aerial photos and satellite imagery) and field data acquisition will provide input to analysis of flood dynamics using a GIS-based analysis. In combination with this the student will undertake interdsiciplinary research to understand the community impacts of the 2017 flood event through newspaper/media analysis, structured interviews and stakeholder workshops. Once an understanding of the modern (recent) flood event has occurred then an analysis of previous El Niño-driven flooding events e.g., 1997, 1982 etc. will be undertaken using archival consultaion and remotely sensed landsat imagery

Project Timeline

Year 1

• Review of existing studies of flood geomorphological and sedimentary impacts from Peru and elsewhere. Review of hydraulic model(s). Stakeholder mapping of the key actors engaged in flood management, food production and identification of associated grey literature sources (e.g. strategic plans, evaluations).
• Geomorphic mapping of channel change on the Rio Piura using remotely-sensed data.
• Acquisition of secondary data sets (Aerial photos, LiDAR, DEMs).
• Planning and organisation of the first field season.
• Field expedition – Season 1: Geomorphology, sedimentology, crowd sourced information & stakeholder interviews.
• Processing and analysis of geomorphological & sedimentary data from the field seasons.

Year 2

• Interpretation and synthesis of data from remotely-sensed, field based geomorphological mapping and sedimentary analysis.
• Planning and organisation of field expedition . Geomorphology, sedimentology, crowd sourced information)
• Field expedition – Season 2 (Including stakeholder workshop, archival work and stakeholder interviews).
• Processing and analysis of geomorphological & sedimentary data from the first field season.
• Begin using field data in conjunction with secondary data.

Year 3

• Complete analysis and interpretation of field data from field season 2.
• Complete impact modelling of 2017 flood.
• Present results at an international conference.
• Begin write-up of thesis.

Year 3.5

• A reconstruction of the 2017 El Niño Costero in the Rio Piura including hydraulic and sediment dynamics. Model of previous El Niño Costero floods and also future high magnitude floods on the Rio Piura using updated topographic data which incorporates major post 2017 flood engineering work.
• An analysis of impacts of flooding of El Niño Costero and previous El Niño events.
• Completion of write-up of thesis and feedback documents/presentations to stakeholders.

Training
& Skills

Remote sensing, GIS, Surveying (dGPS & TLS), geomorphological mapping, hydraulic modelling, sedimentology, palaeohydrology, archive work, community interviews, stakegolder workshops, Spanish.

References & further reading

Goldstein, P.S. & Magilligan, F.J. (2011) Hazard, risk and agrarian adaptations in a hyperarid watershed: El Niño floods, streambank erosion, and the cultural bounds of vulnerability in the Andean Middle Horizon. Catena 85, 155–167.

Morera S.B., Condom T., Crave, A., Steer P., & Guyot, J.L. (2017) The impact of extreme El Niño events on modern sediment transport along the western Peruvian Andes (1968–2012). Nature Scientific Reports, 7, 11947. DOI:10.1038/s41598-017-12220-x

Rein, B. How do the 1982/83 and 1997/98 El Niños rank in a geological record from Peru? (2007) Quaternary International, 161, 56–66.

Tote, C. et al. (2011) Effect of ENSO events on sediment production in a large coastal basin in northern Peru. Earth Surf. Process. Landforms, 36, 1776–1788.

Waylen, P.R. and Caviedes, C.N. (1986) El Niño and annual floods on the north Peruvian littoral. Journal of Hydrology, 89, 141-156.

Further Information

Dr Andrew Henderson Andrew.Henderson@ncl.ac.uk
Tel.: +44 (0)191 208 3086

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