Hydrological and hydraulic modelling for the restoration and management of Loktak Lake, Northeast India
Singh, C. R.
PublisherUniversity College London (University of London)
MetadataShow full item record
Loktak Lake is an internationally important wetland in northeast India that provides valuable goods and services to local communities as well as supporting high biodiversity. Over the last three decades ecological modifications have occurred, most notably due to the construction and operation of the Ithai Barrage. The focus on maximising hydropower generation increased mean lake water levels and reduced their annual variability. This thesis synthesises hydrometeorological and related data for the lake and its catchment. Data are employed in coupled hydrological / hydraulic catchment models (MIKE SHE / MIKE 11) of three gauged sub-catchments, which are calibrated / validated using observed discharges. Results are used to estimate ungauged sub-catchment flows. Catchment model results are combined with meteorological data and current abstractions within a water balance model which successfully simulates observed lake water levels. A series of barrage operation options are developed using the water balance model which prioritise the requirements of major stakeholders (hydropower, agriculture, and the lake ecosystem). A final option is developed, which shows that it is possible to balance the demands of these stakeholders. The implications of climate change are assessed by forcing meteorological inputs to the catchment and water balance models based upon a number of climate scenarios. In the majority of these scenarios, river inflows increase resulting in higher lake water levels that could further exacerbate ecological degradation of the lake as well as enhancing flooding of lakeside communities. The elevated water levels may permit additional irrigation abstractions however existing infrastructure limits increases in hydropower generation. The sustainability of the barrage operation options in the face of climate change is assessed. Results suggest that climate change is likely to limit the ability of barrage management to satisfy hydropower and agricultural demands whilst at the same time establishing a more ecologically appropriate lake water level regime.