Identification of critical pollution areas in the Bagmati watershed using a GIS tool : (a case study in Kathmandu, Nepal) | |
| Author | Pokhrel, Damodar |
| Call Number | AIT Thesis no. EV-98-6 |
| Subject(s) | Geographic information systems Pollution--Nepal--Kathmandu--Measurement |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | This research was conducted to define and identify the critical pollution area and sources in the Bagmati River watershed Kathmandu, Nepal. GIS technology was used to estimate the magnitude of the pollution generated from the major land use heterogeneity of the watershed. Digital elevation model (DEM) was made from the contour data to delineate streams and watershed boundary. Pollution source informations like population, livestock industry and land use was collected during the field survey. Individual administrative boundary was considered as the collection unit of the major pollutants loading of biochemical oxygen demand, nitrogen and phosphorus. The industrial, land use and living pollution were aggregated by the GIS overlay analysis capability to get the combined pollution load within the watershed. The contribution of pollution from each administrative unit to the Bagmati River was calculated and critical areas were defined with higher pollution load. An analysis was made to identify the major factors contributing to pollutant loading. The delivery ratio for each watershed was calculated from the generated and wash off load obtained for each watershed. Priority areas for the mitigation of the wastewater treatment was defined based on the potential load and the density of pollution. This research identified that Kathmandu, Lalitpur and Bhaktapur municipalities are the major polluting areas and living beings are the major factors of Bagmati River pollution. Delivery ratio for the watershed was found to vary from 40-60% for BOD and nitrogen but the delivery of phosphorus was exceptionally high due to cremation effect on the riverbanks. Land use and industry has very low contribution to the river pollution compared with the huge pollution load from the domestic wastewater. In the present context, even it is not recommended urgently to separate treatment system of industry but in future, the separate system should be considered by reflecting the situation of industrial waste pollution strength. So emphasis should be given to control the sewage and industrial waste by facilitating wastewater treatment plants for the mitigation of Bagmati River pollution especially in the urban area and onsite treatment promotion in the rural parts of Kathmandu valley. Considering pollution, political, religious and touristic value of the area, this study developed the priority-zoning map for mitigation of both nutrient and carbonaceous source treatments. |
| Year | 1998 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Ha, Sung-Ryong ; |
| Examination Committee(s) | Kaew Nualchawee ;Takizawa, Satoshi; |
| Scholarship Donor(s) | DAAD/Germany; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |