Impact of moving rainfall events on hillslope pollutant transport
Journal
Environmental Earth Sciences
Journal Volume
74
Journal Issue
7
Pages
5989-5999
Date Issued
2015
Author(s)
Abstract
The pollutants from agrochemicals can cause non-point source pollution due to the rainfall-runoff and the associated upland soil erosion processes. In this study, by using ammonia chloride as the pollutant source, a series of laboratory experiments, considering different rainfall durations (including intermittent rainfall) and moving directions, were conducted to investigate the dynamic process of pollutant transport. Runoff generation and soil erosion processes under different rainfall patterns were analyzed to understand the pollutant transport. Several conclusions can be drawn, which are: (1) when compared with moving downstream rainfall scenarios (MDL), moving upstream rainfall scenarios (MUL) can generally be characterized by hydrographs with earlier rise and higher runoff and erosion rates; (2) the pollutant transport is mainly in the form of dissolved states; (3) pollutant concentration c decreased over time t which can be depicted by a quadratic equation, i.e., c = at2 + bt + d; (4) the pollutant loss in short duration and short interval rainfall patterns is affected by pollutant concentration, while the pollutant loss in long duration and long interval rainfall (MDL) patterns is influenced by runoff rates; and (5) in comparison with MDL cases, rainfall patterns in MUL cases lead to less pollutant loss which is dominated by pollutant concentration.
SDGs
Type
journal article