An integrated simulation-MCDM-GIS approach for groundwater management | |
| Author | Gautam, Tirtha Raj |
| Call Number | AIT Diss. no. WM-97-02 |
| Subject(s) | Multiple criteria decision making Geographic information systems Groundwater--Management |
| Note | A dissertation submitted in partial fulfillment of the requirement for the Degree of Doctor of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. WM-97-02 |
| Abstract | An integrated framework for the management and monitoring of a multiaquifer system, considering the interrelated factors and their interaction with each other, has been developed. The framework is comprised of simulation models, geostatistical analysis, multicriterion decision making (MCDM) techniques, and geographic information systems (GIS). The simulation models were used for the assessment of the system behavior in quantitative terms. Geostatistical analysis was made to address the uncertainty associated with the estimation process. The methodology was applied to analyze the management problem of the Bangkok multiaquifer system. On the basis of the hydrogeological characteristics of the basin, flow system was conceptualized for the flow simulator, MODFLOW. Trial and error calibration approach was employed in this study. Calibration was guided by several measures of calibration target obtained from the geostatistical analysis of the observation data. The final calibration run was considered to be satisfactory based on the criteria that the discrepancy between the observed and the simulated piezometric head values were within the allowable range of error obtained from geostatistical analysis of the observed data. From the several steps involved in modeling, it was realized that trial and error calibration of a groundwater model can be enhanced by introducing the calibration target and level of calibration through the geostatistical analysis of observed data. Similar approach was employed to develop the MT3D based transport model and an one-dimensional consolidation model. Calibration for these models was not as rigorous as flow modeling as the available information for these models were not sufficient to do so. The subsidence model was calibrated for ten representative locations for which detailed stratigraphic information and reliable historical observation were available. All the three calibrated models were used to evaluate the potential development plan and policies of the groundwater management authority. Six development scenarios were proposed considering the domestic and the industrial water demand, its rising pauem over the past and expansion of the surface water supply network. Prediction of the associated impact of the groundwater development including drawdown, water quality deterioration and subsidence was made for the scenarios using the simulation models. Predictive analysis shows that if proper action is not taken, state of the Bangkok groundwater water system is expected to deteriorate at an alarming rate. With the measures proposed, stabilization of water level drop and salt water movement can be expected but subsidence is expected to continue though the rate decreases significantly. The tradeoff between ever increasing demand for water withdrawal and adverse environmental cum socio-economic factors involved in the groundwater management were dealt with by using multicriterion/multiobjective decision making (MCDM) approach. GIS assisted MCDM analysis (spatial MCDM) was found to be a powerful tool for the investigation of the spatial distribution of the environmental impact considering the multiple aspects of it such as water level drop, quality degradation and subsidence simultaneously. A methodology for the design of a monitoring network for a multiaquifer system was also developed addressing the issues of economy, operational and administrative convenience and monitoring of multiple variables for a multiaquifer system. The methodology incorporating optimization, geostatistical analysis and multicriterion evaluation is composed of three steps: quantification of estimation error through kriging, optimization of the network layout for a particular variable using simulated annealing method and the MCDM evaluation of the alternatives developed by repeating the optimization process for each variable to be monitored. From practical point of view and financial availability, an optimal expansion strategy for the Bangkok aquifer system was determined using the proposed methodology. It was found that the present groundwater monitoring network has to be expanded. For two conditions that have been investigated namely the optimal expansion of the monitoring network maintaining the existing network, and fully optimal design without considering the existing stations, the analysis provided almost equally good performance for a network composed of 130 monitoring stations. Thus optimal expansion is preferred to the fully optimal design which discards many of the existing well without significant improvement in the performance. |
| Year | 1998 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. WM-97-02 |
| Type | Dissertation |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Gupta, Ashim Das ; |
| Examination Committee(s) | Loof, Rainer ;Vachi Ramnarong ;Tabucanon, Mario T. ;Sadananda, Ramakoti ;McBean, Edward A. ; |
| Scholarship Donor(s) | Deutsche Gesellschaft Fur Technische Zusammenarbeit (GTZ), Federal Republic of Germany ; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1998 |