GEODETIC INVERSION FOR AQUIFER DAMAGE MODEL IN SEMARANG CITY BASIN, CENTRAL JAVA, INDONESIA
An aquifer may be defined as a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs. Aquifer system in Semarang city basin is mainly divided into two different types including unconfined aquifer with an average depth of 3 –...
Saved in:
| Main Author: | |
|---|---|
| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/40110 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | An aquifer may be defined as a formation that contains sufficient saturated permeable
material to yield significant quantities of water to wells and springs. Aquifer system
in Semarang city basin is mainly divided into two different types including
unconfined aquifer with an average depth of 3 – 18 meters and confined aquifer with
an average depth from 50 – 90 meters.
Urbanization and industrialization processes cause groundwater in Semarang city area
to be overexploited to meet the needs for domestic and industrial use. As a result, the
aquifer system in Semarang city is being partially damaged. Damaged aquifer has the
lower possibility to store the water because its void, porosity and hydraulic
conductivity are reduced dramatically. Damaged aquifer also intensifies water
scarcity and affects the water security in the future.
There is a difficulty in estimating water table decline due to the limited on-site
groundwater data. Luckily, there is correlation between water table decline and land
subsidence from existing publications in several places across the world. While
aquifer damage can be estimate from water table decline value. The correlation is
used as an alternative to do inversion to calculate water table decline from land
subsidence data. Therefore, this research is to create two mathematical models for
estimating water table decline. Model 1 is built based on the field data of groundwater
in Semarang in correlation with land subsidence data and Model 2 is built by using
the correlation data from existing publications.
The research shows that Model 1 and Model 2 well represent for the correlation
between land subsidence and water table decline in Semarang city basin. The two
models give the similar resulting water table decline. Consequently, the two models
can be used interchangeably. Moreover, Model 2 can be also used for other places in
the world in consideration of VS30 similarity.
According to water table decline value estimated by both Model 1 and Model 2, more
than 70 percent of the aquifer system of Semarang city basin will be damaged and
very damaged in 2050 if there is no action taken to stop the subsidence phenomenon.
|
|---|