Gewählte Master / Diploma Thesis:

Alexander Oeze (2002): Assessment of downstream impacts of an irrigation extension project in Uda Walawe, Sri Lanka.
Master / Diploma Thesis, BOKU-Universität für Bodenkultur. UB BOKU obvsg

Data Source: ZID Abstracts

Abstract:

The Karagan lagoon is one of the few remaining brackish water lagoons in the south of Sri Lanka. It is feared, that the ongoing Uda Walawe irrigation upgrading and extension project might have negative ecological impacts on the lagoon by increased inflow of fresh water. Thus, water levels could rise, salinity might drop, etc. Similar things happened to other lagoons nearby. For the Karagan lagoon there is the unique opportunity to conduct a pre-implementation assessment of the present state of the lagoon, with respect to water quality, biodiversity, etc. However, this study deals with hydrology only, also because hydrology is a very influential factor for all the other parameters. Therefore, the scope of this study was to assess the quantities of inflowing and outflowing water. Because in the time, when this study was conducted, there was no measureable flow, a different methodology had to be adopted in order to estimate how much water could flow in the rainy season. A simple, spreadsheet based simulation model was set up to simulate inflow into the lagoon from meteorological input data. However, because no flow data was available, the model could not be properly calibrated. But in order to get at least preliminary results, the calibration parameters in the model were changed in a way, so that the components included in the model would plausibly match with the behaviour of their real world counterparts, which was derived out of numerous talks with local farmers. As a second step, the changes, that will be brought along with the irrigation extension project were tried to be incorporated into the model, in an attempt to make cautious predictions about the future. Although uncalibrated yet, the model indicates, that the inflow into the lagoon is very likely to rise significantly.

Beurteilende(r): Loiskandl Willibald

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