Authors: Sashini Pathirana, Lakshman Galagedara, Jagath Gunatilake
Identifier: CSBE21800
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Published in: CSBE-SCGAB Technical Conferences » 5th CIGR and AGM Quebec City 2021 » Special Session on Hydrological Modelling: a Tool for Resilient and Sustainable Agriculture

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Description: Field scale measurement and mapping of the spatiotemporal variability of depth to the groundwater table (DGWT) is difficult. HYDRUS-1D is a public domain hydrological model for simulating one-dimensional movement of spatial or temporal variability of water, heat, and solute in a porous media. This study evaluated the accuracy of HYDRUS-1D model for predicting DGWT. In achieving this goal, HYDRUS-1D model was calibrated using observed DGWT data of consecutive 320 days (23rd of June 2017 - 8th of May 2018) and validated using 120 days data (9th May - 5th September 2018) in Newfoundland, Canada. Precipitation data from the nearest weather station and observed DGWT data from a monitoring borehole located in the study site were used. Deep drainage parameters, Aqh and Bqh were found as the sensitive parameters to predict DGWT. Aqh and Bqh parameters were adjusted manually during the calibration and found to be -0.60200 cm/day and -0.00840 1/cm, respectively. Resultant Aqh and Bqh parameters were used for validation. Root mean square error and coefficient of determination between observed and simulated DGWT values during model calibration were 15.85 cm and 0.75 and during validation were 13.35 cm and 0.87, respectively. Simulated DGWT underestimated during both calibration and validation. It was also found that simulation results did not respond to precipitation peaks. If long-term field observations covering higher variability with multiple boreholes together with detailed soil information for the entire profile were available, calibration of the model and the resultant prediction to DGWT could be achieved with higher accuracy.

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Date: 2021-06-11
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Conference name: 5th CIGR International Conference and CSBE-SCGAB AGM 2021, Quebec City,QC, 11-14 May 2021.
Session name: SPECIAL SESSION Hydrological modelling I

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Type: Text.Abstract
Publication type: Presentation
Coverage: Sri Lanka
Language 1: en
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Rights: Canadian Society for Bioengineering
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