An integrated model for conservation planning based on precipitation-runoff relations, soil loss, and sediment characteristics at field boundaries.

Gabriel Lobo, Carlos Bonilla, Rocío Céspedes, Virginia González

Wednesday 1 july 2015

12:00 - 12:15h at Oceania Foyer (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 9H. Water resources - Catchment

Soil erosion is an undesirable phenomenon from both an agricultural and environmental point of view in many agricultural watersheds all over the world. Unfortunately, monitoring the efficacy of efforts to reduce soil and chemical loads is complicated by the fact that they take place in varying soil, climate, and management contexts. Therefore, the objective of this study was to investigate the precipitation-runoff relations, soil loss, and sediment characteristics at field boundaries in Central Chile, and built a model for soil conservation and water quality planning suitable for the local conditions. The study area covers the Central Valley in Central Chile, which includes most of the cultivated and productive land in the country. In the absence of long-term monitoring of field plots, an integrated modeling of environmental and agricultural processes was used to identify those variables that best explain the soil loss and sediment composition at field boundaries. By carrying out the model simulations, a large plot-years database of rainfall, runoff, and soil data was generated. Soil loss and sediment characteristics were related to a number of variables using regression techniques developing a model for predicting precipitation-runoff relations, soil loss, and water-quality characteristics at field boundaries in the region. This study moves away from the more traditional assessments of the on-site impacts of soil erosion on soil productivity and degradation to focus on the wider off-site environmental impacts of soil loss and more particularly its potential role in nonpoint source pollution. The latter impacts extend well beyond water quality and also include the impact of sediment and sediment-associated nutrients in degrading aquatic and riparian habitats and ecosystems.