Monitoring and modelling water quality of Loktak Lake catchment

Abstract

Loktak Lake is an internationally important, Ramsar designated, fresh water wetland system in the state of Manipur, India. The lake has also been listed under Montreux Record on account of the ecological modifications that the lake system has witnessed over time. Discharges from nine rivers namely Khuga, Thongjaorok, Awang Khujairok, Nambol, Nambul, Imphal, Kongba, Iril, and Thoubal have a great impact on the habitats and the overall ecological status of the lake. Monitoring of water quality at the catchment scale can be considered as an essential step towards the eventual goal to design effective conservation and management practices for the entire Loktak Lake ecosystem. This article presents the status of nine rivers draining into the Loktak Lake and correlation with land use patterns which can be used as support for making sound decisions regarding the management of the lake ecosystems. Flows were modelled using a combination of soil and water assessment tool (SWAT) and MIKE SHE, abbreviated as hybrid SHE-SWAT. Water quality models were established using MIKE 11 ECO Lab. Water quality parameters such as biological oxygen demand, dissolved oxygen and water temperature were simulated. Water quality models were calibrated using available measured water quality data procured from State Pollution Control Board and validated using observed water quality collected during the field study.

Water quality assessment of Loktak Lake, Northeast India using 2-D hydrodynamic modelling

“…Daily flows and water quality variables were simulated for the time period January 2011 to December 2016. Details can be found from the previous work, Khwairakpam et al [27,28]. The models were based on field data collection, visual inspections and observed data procured from Loktak Development Authority (LDA) and State Pollution Control Board (SPCB), Manipur.…”

“…Initially, hydrological models of nine sub-catchments namely Khuga, Western, Nambul, Imphal, Kongba, Iril, Thoubal, Heirok and Sekmai using hybrid SHE SWAT were developed. Details can be found from the previous work [27,28]. Daily discharge simulated from the models were specified as inflows to Loktak Lake.…”

“…Simulated water quality of rivers were specified as boundary condition. Water quality (state) variables of rivers were simulated using MIKE 11 ECO Lab in the previous work, Khwairakpam et al [28] [27]. A field sampling was also done for six monitoring stations M1, M2, M3, M4 M5 and M6 as shown in Fig.…”

“…Models were validated for dry (25-31 January 2016) and wet (5-15 August 2016) seasons. Details can be found from the previous work [27].…”

Impact of sewage effluent discharges prediction using QUAL2Kw in a sensitive protected area: Portugal

“…Pollution simulation is a serious issue as it has consequences for hydrological modeling and discharge predictions for environmental impact assessment [14][15][16][17]. Modeling can be a useful management tool because models allow understanding the water body response to different pollution pressure scenarios which may assist in the decision-making process and in prosecuting the Water Framework Directive objectives.…”