Assessing potential salt-vulnerable areas through terrain analysis using remote sensing and GIS - the Vientiane Plain case study | |
| Author | Nokeo Ratanavong |
| Call Number | AIT Thesis no.NR-91-04 |
| Subject(s) | Salinization--Vientiane Plain Salinization--Remote sensing GIS (Computer program) |
| Note | A thesis submitted in partial fulfillment of the requirement for the Degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. NR-91-04 |
| Abstract | Salt-affected areas in the Vientiane Plain have been created by a salinization process operating primarily via saline groundwater. They are characterized by the occurrence of highly saline barren patches with few halophiles, surrounded by apparently less or non - saline areas. The saline patches show an uneven distribution within t he topographically low-lying terrains. Salt- affected areas can be observed o n remotely-sensed images with the help of secondary indicators and verified by ground truth surveys. Besides soils affected by salt at present, potential salt-vulnerable soils must also be distinguished. Soils considered potentially salt-vulnerable are those that are not, or only to a mi n o r degree, saline at present, but with environmental changes could become salt-affected. Potential salinity classes are based on a combination of factors rather than t he presence of surface salt occurences only. Highly salt- vulnerable areas are located within low- lying areas with shallow watertables, of saline quality, underlain by the Tha Ngone salt-bearing Formation, with fine textured soils a nd inefficient drainage, and covered with sparse vegetation. A sandy soil is rarely a salt- affected soil because t he soil is well drained a nd the salt can be leached out easily. A clayey soil is likely to be salt-affected if t he salts are introduced by surface water. A loamy soil is likely to be affected if t he ground water is saline because the capillary rise is higher than in other soils. Paddy fields may favor the development of salinization. These fields need poor drainage conditions for rice cultivation, which is one of the factors favoring salinization if combined with other environmental factors. Potential salt-vulnerable areas could be assessed at a reconnaissance level by integrating and analyzing the necessary environmental data and information. Further field and analytical data are needed for more adequate modeling. |
| Year | 1991 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. NR-91-04 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Natural Resources Management (NRM) |
| Chairperson(s) | Lukens, John E. |
| Examination Committee(s) | Prinya Nutalaya ;Motti, Etienne |
| Scholarship Donor(s) | SIDA ( Swedish International Development Agency) ; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1991 |