liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
GIS-supported modelling of areal rainfall in a mountainous river basin with monsoon climate in southern India
Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
2000 (English)In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 45, no 2, 185-201 p.Article in journal (Refereed) Published
Abstract [en]

Spatial rainfall patterns and seasonal variability were assessed for a mountainous river basin with monsoon climate. Factors were identified that could explain this variability, and a GIS-supported method to determine the areal distribution of precipitation was developed. To find acceptable regression equations, a division had to be made between rainfall stations dominated by the southwest-monsoons and the northeast-monsoons, respectively. Distance to the southwestern border was the main explaining factor for precipitation at southwest-monsoon dominated stations. For northeast-monsoon dominated stations, altitude and slope were the most important factors. The basin was divided into pixels with characteristics typical for northeast- or southwest-monsoon dominated rainfall stations to allow calculation of spatial rainfall. The difference when comparing regression-based estimates with Thiessen-based estimates was small when considering the annual estimates for the whole basin. However, when analysing seasonal rainfall or sub-catchments, the differences between Thiessen-based and regression-based estimates were significant.

Abstract [fr]

La structure spatiale et la variabilité saisonnière de la pluviosité ont été déterminées pour un bassin versant montagneux soumis à un climat de mousson. Les facteurs susceptibles d'expliquer cette variabilité ont été identifiés et une méthode assistée par SIG de détermination de la distribution spatiale des précipitations a été développée. Afin d'obtenir des équations de régression acceptables nous avons dû distinguer les stations pluviométriques soumises à la mousson du SO de celles soumises à la mousson du NE. La distance à la frontière SO s'est révélée être le principal facteur explicatif des précipitations pour les stations soumises à la mousson de SO. Pour les stations soumises à la mousson de NE, l'altitude et la pente se sont révélées être les facteurs explicatifs principaux. Le bassin a été divisé en pixels auquels les caractéristiques des stations soumises à la mousson du NE ou du SO ont été affectées pour pouvoir calculer la pluie spatiale. Les différences entre les estimations fondées sur les régressions et celles fondées sur la méthode de Thiessen sont petites lorsque l'on considère le bassin complet à l'échelle annuelle, mais elles peuvent devenir importantes lorsque l'on considère les sous-bassins à l'échelle saisonnière.

Place, publisher, year, edition, pages
2000. Vol. 45, no 2, 185-201 p.
National Category
Social Sciences Interdisciplinary
Identifiers
URN: urn:nbn:se:liu:diva-31760DOI: 10.1080/02626660009492319Local ID: 17583OAI: oai:DiVA.org:liu-31760DiVA: diva2:252583
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Do forests have an impact on water availability?: Assessing the effects of heterogeneous land use on streamflow in two monsoonal river basins
Open this publication in new window or tab >>Do forests have an impact on water availability?: Assessing the effects of heterogeneous land use on streamflow in two monsoonal river basins
2000 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this thesis is to assess the effects of land use changes on streamflow in two river basins, the upper Bhavani in south India and the upper Nam Pang in northeast Thailand. In the Nam Pang basin, the forest cover has decreased from 80% to 27% in the last 30 years. Despite this, almost no changes in streamflow patterns or amountswere found. The figures depicting a drastic reduction of indigenous forest are partly misleading. In areas, where swidden agriculture has been the cause of forest encroachment, large numbers of shade trees were retained thus the density of trees in the catchment has not been as radically reduced (219 trees ha·1 to 104 trees ha-1 ) as the amount of forest cover indicates. Many abandoned plots of land, have also been rapidly replaced with secondary vegetation, which attain evapotranspiration rates close to that of mature forests in only a few years. This would indicate that substituting indigenous forest witha mosaic of open land and mixed trees does not affect the streamflow amounts as drastically as has been observed in small catchments where an area of forest is cleared simultaneously and replaced with homogeneous cropland.

People in both catchments valued trees highly for productivity functions such as firewood, food items, medicines and aesthetic reasons. Forests were also believed very closely linked with a sustained water availability in terms of rain and streamflow. Because of how highly forests are valued, there was a strong interest in both conserving the indigenous forests that still exist today as well as retaining and planting scattered trees. This would aid the maintenance of a landscape mosaic that should according to the results presented in this thesis, not drastically affect streamflow regimes from more heavily forested conditions.

Study work in the upper Bhavani catchment, India, was riddled with data uncertainties that made modelling work wrought with extra challenges. Even in areas such as this, where data is insufficient in relation to the area's hydrological and climatological complexities, people have an interest in understanding their local hydrological regime. It is therefore justifiable to model these areas, if the available data is assessed until an acceptable level of reliability is obtained. Results should then be presented and interpreted in light of these data uncertainties. Results from the modelling of different land use scenarios supported the results from the upper Nam Pang catchment, Thailand where more heterogeneous land use conditions, showed little changes in streamflow regimes compared to a hypothetical indigenous scenario. Most extreme changes in annual water yield were caused by the scenarios representing total conversion of the catchment to agriculture (+19%) and plantations (-33%) while changes in assured yield at the Bhavanisagar reservoir, a measurement indicating downstream water sustainability, were more modest.

In summary, the retention of heterogeneous land use can buffer the effects of large changes in streamflow as found in small-scale catchment studies. It is very likely that people that enter a forested area to undertake small-scale agriculture will maintain existing forests and plant scattered tree groves for the many products and services that trees are perceived to provide, thus propagating a landscape mosaic.

Place, publisher, year, edition, pages
Motala, Sweden: Motala Grafiska, 2000. 79 p.
Series
Linköping Studies in Arts and Science, ISSN 0282-9800 ; 222
National Category
Social Sciences Interdisciplinary
Identifiers
urn:nbn:se:liu:diva-31783 (URN)17607 (Local ID)91-7219-882-6 (ISBN)17607 (Archive number)17607 (OAI)
Public defence
2000-12-08, Hörsal Planck, Fysikhuset, Universitetsområdet Valla, Linköping, 10:15 (Swedish)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-07-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Wilk, JulieAndersson, Lotta

Search in DiVA

By author/editor
Wilk, JulieAndersson, Lotta
By organisation
Department of Water and Environmental StudiesFaculty of Arts and Sciences
In the same journal
Hydrological Sciences Journal
Social Sciences Interdisciplinary

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 112 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf