| Author | Pham Huy Giao |
| Call Number | AIT Diss. no. GE-96-02 |
| Subject(s) | Artificial recharge of groundwater--Thailand-Bangkok
|
| Note | A dissertation submitted in partial fullfilment of the requirement
for the degree of Doctor of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. GE-96-02 |
| Abstract | Extensive groundwater pumping in Bangkok has led to drastic piezometric drawdown
and land subsidence which aggravates the situation of flooding the city and its vicinity are facing
annually. Land subsidence is so evident that nowadays its effect must be considered in design
of civil engineering structures, e.g., high-rise buildings, road embankments, flood protection
system. Aimed at solving this environmental hazard, control of groundwater pumping has been
exercised, but it is not yet effective due to rapid economic growth, uncontrolled urbanization
and inadequate network of surface water supply. In this circumstance, artificial recharge, if
technically viable, would be, a valuable tool to help recover head declines in the deep aquifers
and mitigate land subsidence of Bangkok.
As the first and indispensable step in application of recharge, a field experiment was
carried out in this study to investigate specific features of well recharge into the uppermost
aquifer of the Bangkok system and to bring out possibilities of further application to the deeper
aquifers. As results, practical guidances on design, construction and operation of a recharge
borehole as well as procedures in setting up a recharge experiment, collecting and analyzing
test data were obtained. Clogging of the recharge well was paid a special attention to. Two new
parameters, i.e.Recharge Clogging Factor (RCF) and Clogging Development Radius (CDR),
were proposed to help quantitatively analyze clogging around the injection well, and they
proved to be useful in later FEM simulation of a recharge test curve.
A general solution of quasi-3D model for modelling of responses to well recharge in
a multiaquifer system was developed, employing a combined technique of FEM and convolution
integral. Based on this algorithm, a FEM program named QSI3D was written in FORTRAN
77 and it can be run on any IBM compatible PC for large dimension problems. Besides the
program QSI3D, two more FEM programs were also developed, namely, RCHB for analysis
of recharge test data and TZ for analysis of change in pore pressure, stress and soil compression
in an injected soil profile. This study is the first work on FEM groundwater modelling of Bangkok
aquifer system and subsidence analysis with reference to artificial recharge. Analyses were done
for an idealized hydrogeological model of Bangkok aquifer system as well as for some real deep
soil profiles to investigate soil compression/rebound and hydraulic responses to artificial
recharge. The results indicated that compression of hard clay layers caused by overpumping
has not yet propagated beyond the depth 250 m, below the most exploited aquifers. Several
schemes of artificial recharge were studied to show abilities of mitigation of land subsidence
by recharge. A new concept of critical drawdown was proposed for safe groundwater extraction
from the point of view of land subsidence control. The study showed that artificial recharge is
the only viable technical means to prevent further head declines in the deep aquifers of the
Bangkok aquifer system. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. GE-96-02 |
| Type | Dissertation |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Noppadol Phien-Wej; |
| Examination Committee(s) | Prinya Nutalaya;Gupta, Ashim Das;Bouwer, Herman ; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1997 |