Assessing land use and land cover influence on surface water quality using a parametric weighted distance function

LIBEROFF, ANA LAURA; FLAHERTY, SILVIA; GARCÍA ASOREY, MARTÍN I.; HUALDE, PABLO; FOGEL, MARILYN; PASCUAL, MIGUEL

LIMNOLOGICA

ELSEVIER GMBH

Año: 2018

0075-9511

Water quality in watersheds is directly influenced by land use and human practices in the surrounding environment. Understanding such effects and the spatial extent of impacts is essential to generate reliable information for ecosystem-based management of water resources. We identified sources of impact on water quality and characterized indicator-specific landscape influence on samples taken during base flow along the Chubut River (43ºS, 69ºW). We modeled Total Nitrogen (TN), Total Phosphorous (TP), Soluble Reactive Phosphorous (SRP) concentrations and 15N of particulate organic matter along the river, as a function of Land Use / Land Cover. Our model assumes that the landscape influence decays exponentially with the Euclidean distance to the point of interest. We calibrated the model to the observations by estimating an indicator-specific decay rate. Phosphate nutrients were positively related to barren land and cropland in upstream areas; radius of landscape influence for SRP was larger than for TP (100-180, 10-25 km respectively). TN increased steeply downstream of main urban areas but typical radius could not be identified. 15N variation was explained by vegetation cover at a local scale (1-4 km). Soil degradation, agriculture and urbanization are the main drivers of N and P cycles alteration in this system.