Interdisciplinary and cross-sectoral knowledge construction of floods alerts, at the Matanza River in eastern Argentina

NADIA TESTANI; FEDERICO ARIEL ROBLEDO; DIEGO MOREIRA; CAMILA PRUDENTE; MARIANO RE; KAZIMIERSKI, LEANDRO DAVID; MICOU, ANA PAULA; GATTI, IGNACIO AGUSTIN

Australia

Conferencia; 28th AMOS Annual Conference: Science for Impact; 2021

Australian Meteorological and Oceanographic Society

One of the most challenging extreme events that governments have to afront due to their direct impact on population are urban floods. That is the reason why evaluating and monitoring urban basins turns out to be a priority. In order to do that, the challenge of science is the improvement of the development of products derived from numerical modelling of rivers and advance with the social validation and assimilation of these products through local knowledge. With that objective, the ?Anticipando la Crecida? team was created in March 2013 with researchers and technicians from institutions of the Argentine scientific sector, in dialogue with local governments and stakeholders from civil society in different locations in the metropolitan area of Buenos Aires. In this study we develop and apply a methodology to improve the understanding of floods and create a local early warning system (EWS) at the Matanza River basin, a rural-urban sub-basin of La Plata Basin, located in Buenos Aires, at the east of Argentina, where more than five million people live, in order to reduce the effects of disaster risk.With the aim of facilitating the interface between science and policy and to develop effective decision-making in disaster risk management it is fundamental to promote and improve the dialogue and cooperation among scientific communities, stakeholders and policymakers. Since 2014 we have been in permanent dialogue among these three actors from different localities of La Matanza basin to jointly understand its behaviour and to generate a local early warning system (EWS) in order to face the floods of the Matanza river and its tributaries. Through this dialogue, the scientific-academic knowledge of different disciplines (meteorology, oceanography, geography, anthropology and engineering) was joined to the local community knowledge of different actors in the localities of La Matanza Department such as Local Civil Defense (DC); teachers, students and directors of schools that work as evacuation centers in flood events; community based organizations and the Science and Technology area of the local government.Firstly, an analysis of knowledge of risk on a block scale was carried out through participatory mapping workshops in the territory and field tours in dry and flood situations. This co-produced information was incorporated for its organization and visualization into the Geoportal at the National Geographical Institute (IGN), whose objective is to produce geospatial information and make it available for access to all citizenship through a web platform. Not only have local actors contributed with their knowledge of the basin and risk at a local scale but also they have started monitoring rain and river level. At the beginning of 2019 manual rain gauges were installed in different areas of the basin and the community was trained to carry out a daily measurement and share it through cellphone in a group conformed of local referents and scientifics. La Matanza River level has been measured after each rain event from DC since December 2018 with an stream stage installed at the Ricchieri Highway bridge. Moreover, in 2019 a new stream stage was installed in a tributary of La Matanza River and it is being observed by a community based organization member. As a result of this work, a co-produced community network for measuring rain and river level was created. La Matanza Basin is a plain basin characterized by a response time of approximately 48 hours on the middle basin, where most people live. That characteristic allows a simple hydrological model to anticipate the Matanza river level in the middle and low basin on a daily scale once it has rained. This motivates the calibration of the Sacramento hydrological model in three points into La Matanza basin in view of putting it operative so as it could be part of the EWS. To calibrate the model we use non-continuous level and flow data in the period of 2013-2015. However, the measurements of La Matanza Community network are fundamental for the validation of this model seeing that they correspond to a more current period. In this way, the community monitoring network and knowledge of local risk provides robust social and hydro-meteorological information for local planning of risk management by the communities. Moreover, the hydrological model that was validated with measurements of the local network is a strong tool to anticipate floods into the basin and to study its behaviour so it turns out to be very useful for the local government for decision making.