Sediment Budget: From Hillslope to in-Stream Processes.

Sediment is an important non-point source contaminant in waterbodies around the world, which could also be related to the availability of nutrient fluxes. To define waterbody, watershed or regional management actions to reduce sediment loading, it is necessary to identify the source, mechanisms and rates of erosion or sediment deposition, as well as their controls. Considering a sediment budget refers to the balance between sediment added to and removed from a waterbody, the primary component for any sediment management plan is a sediment budget. Although sediment input in a reference waterbody may be considered from different sources, not all sediment budgets take account of all forms of input or output. We have evidenced how streambank erosion processes can contribute up to 90% of the sediment load assessed at the outlet of a watershed. However, some watershed models, developed to identify the establishment of management practices at large scale within a specific area, are built and evaluated considering upland erosion processes as the main and sometimes only source for sediment loads at the outlet of the watershed. It could lead to the inappropriate design and/or establishment of best management practices (BMPs) or large scale management plans and actions, which could derive in the accelerated detriment of the scope waterbody or watershed. The purpose of this presentation is to evidence how soil and other environmental scientists can contribute to the appropriate assessment of erosion processes, and to the preparation of sediment budgets to make them act as a structure for a research agenda on watershed or regional processes.