Data limitations in developing countries make river restoration planning challenging. Study case of the Cesar River, Colombia

Past research has mapped the limitations of water quality data in developing countries. This contribution reports a detailed assessment of the status of water quality data of the Cesar River, one of the main tributaries of the Magdalena River, which is regarded as the largest river system in Colombia. Our assessment indicates that the data is limited (in terms of length of record and resolution spatial) and exhibits significant information gaps, and that it is collected through a network of very sparse ground stations with deficient density. Subnational permissible limits for the five main water quality parameters (i.e., pH, TP, TN, DO, TSS) determine that water has reached worrisome levels of pollution. The data limitations does not allow for establishing the influence of natural (e.g., soil erosion) or anthropogenic processes such as wastewater discharges and in-channel sand mining into water quality. Since Colombia is a member of the Pacific Alliance and the Organisation for Economic Co-operation and Development (OECD) the associated supranational water quality regulatory frameworks are analyzed as they may guide the permissible limits and targets in the coming years. A freely accessible database of water quality observations between the years 2004–2020 of the Cesar River accompanies this contribution. We believe that it potentially constitutes a scientific input to plan for restoring the ecosystem services of the Cesar. We also believe this study depicts a representative case of the status of several rivers from the Latin American sphere and other developing countries.