How much down the ditch? Perception and realities
| MSI03P3938 | |
| Chung Tze Cheong, M. Pullar, D. Hunter, H. Ng Kee Kwong, K. F. | |
| How much down the ditch? Perception and realities | |
| ISSCT Agronomy workshop: Opportunities in sugar cane agronomy to confront the new realities emerging in the 21st century, 21-25 July 2003, MSIRI, Mauritius: Program and Abstracts | |
| book chapter | |
| 2003 | |
| p. 31 | |
| Reduit: ISSCT and Mauritius Sugar Industry Research Institute | |
| En | |
| En | |
| Sugar cane fields comprise about 45 per cent of the total land area of Mauritius. This has caused a strong perception during the past decades that the sugar industry is a major polluting agent in Mauritius, especially after heavy rains. Preliminary results obtained from lumped catchment hydrology modeling of agrochemical movement in tropical sugar production have shown that the N pollution of streams is agronomically not important, but may be environmentally significant. However, a closer look at the catchment revealed the incidence of point source pollution inputs from other inland and in-stream activities, apart from sugarcane cultivation. Their contribution to the detected N loads was ignored in the original catchment N model. In addition, the fact that the catchments in Mauritius are found mostly on a multilayered aquifer zone with faults, the subbasin definition, stream nodes and soil parameters need to be refined with soil pit data, borehole data, and geology information. A methodology adapted for the Non-Point Source (NPS) pollution evaluation in a catchment is presented to improve the flow calibration of the geologically complex catchments of Mauritius. A framework for various sources' data compilation and preprocessing is proposed to generate the necessary parameters as inputs into a simplified integrated surface and subsurface model, based on topography, geology, and land use. Two models using Geographic Information System tools were selected for the study: Soil and Water Assessment Tool (SWAT), a physically-based distributed surface water hydrology model, and Hydrogeomorphic Analysis of Regional Spatial Data (HARSD), a groundwater modeling software which classifies landscape into hydrogeomorphic units for subsequent inference of hydraulic head surface. The latter is used as input into a groundwater flow model for flux calculations. In addition, a submodel is derived from the balance sheet for N sources and sinks in the catchment. The thematic layer derived for N contribution by sugarcane to catchment would be used to crosscheck the measured values, after elimination of point sources pollution detected along the stream. Using these models, a better picture of sugarcane's contribution to NPS pollution in the catchment has emerged. | |
| Geographic information systemS surface and subsurface hydrology modeling non-point source pollution sugarcane | |
| Mauritius | |
| Sugarcane: Soils and plant nutrition | |
| Pollution | |
| 2003-07-31 | |
| En | |
| MSIRI Department of Geographical Science and Planning, Univ of Queensland, Australia Department of Natural Resources and Mines, Indooroopilly, Queensland, Australia | |
| LIB | |
| CHEM GIS |