CONICET | Buscador de Institutos y Recursos Humanos

The eutrophication of waterways has become an endemic global problem. Nutrientenrichment from agriculture activities and waste water treatment plants are majordrivers, but it remains unclear how lowland sandy rivers respond to eutrophication.The objective of this study was the development and verification of eutrophicationindex for sandy rivers (EISR) to prioritize nutrient enrichment river stretches causedby different land use activities that include point and nonpoint sources of nutrientenrich water. The Berg River drainage system in South Africa served as a casestudy area for this purpose during the dry seasons (December and January) of2015 and 2016. In the initial EISR development phase, periphyton, benthic biomass(chl‐a mg m−2), and macroinvertebrate families were employed as benthicbioindicators of river bedforms, whereas in the second phase, physicochemicaland abiotic variables were used as target indicator. Using a weight of supportapproach, the site receiving sewage effluent was categorize as heavily pollutedwhereas sites impacted by agriculture land use activities were polluted. The EISRthat focuses strongly on benthic bioindicators, which are close to the transfer ofnutrients and energy in the food web, showed a distinct difference between riverbedform impacted by sewage effluent and agriculture none point source. A maximumbenthic algae biomass of 110 mg m−2 chl‐a was recorded with higher sedimentorthophosphate concentration at sewage‐impacted sites. The outcome ofthe proposed EISR showed that it can be employed as a decision support toolfor eutrophication management of sandy rivers.