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Journal ArticleDOI

Groundwater Vulnerability from Sea Water Intrusion in Coastal Area Cilacap, Indonesia

30 Aug 2019-Indonesian Journal of Geography (Universitas Gadjah Mada)-Vol. 51, Iss: 2, pp 206-216

AbstractThe important issue relating to water resources is sea water intrusion (SWI) phenomena. Nowadays, the phenomena has become serious problem in the urban coastal area. Groundwater as main sources for domestic usage cannot be used again because of its salinity.Cilacap as one of urban coastal area also face the problem. In 1977 SWIwas detectedand experienced significant developmentsin 1996,This research was conducted to: (1) analyze agroundwater vulnerability to the SWI; (2) determine adistance and adepth theinterface; and (3) analyze relationship of the groundwater vulnerability to the interface depth.It was performed an analysis of the groundwater vulnerability to the SWI using the method of GALDIT, whereas the distance and depth of the interface was determined using the method of DupuitGhyben-Herzberg. The linkage analysis of the groundwater vulnerability to the depth of the actual interface was conducted by quantitative descriptively.The results showed that the distance from the shoreline was the most determined factor of the groundwater vulnerability to the SWI, the closer to the shoreline the more swallow the depth of the interface.  It existed the relevance between the vulnerability level of groundwater to the SWI with the depth of actual interface. The regions with low level of vulnerability had deep interface depth, whereas the regions with moderate level of vulnerability had swallow interface depth.  Nevertheless, the SWI has not yet affected the groundwater in people wells because of its depth that was not yet exceeded of 25 m.so that this depth can be used as a reference in digging wells in the research area++

Topics: Groundwater (53%)

Summary (2 min read)

Introduction

  • Because of this location, coastal areas are vulnerable to various problems such as SWI and tidal flooding.
  • Partly citiesin Java, Indonesia are located incoastal area, such as:Jakarta, Cirebon, Pekalongan, Semarang, and Surabaya are some of cities located on the northern coast of Java, whereas Cilacap is located on the southern one of Java Island.
  • With the GALDIT, it can be seen the environmental condition of a place related to its vulnerability including the distance from the shore line, whereas with the Dupuit Ghyben-Herzberg, the depth of the interface can be known at a certain distance on the shore line.

Determination of Groundwater Vulnerability

  • It was conducted a research using GALDIT method to get the information about groundwater vulnerability fromSWI.
  • GALDIT stands for parameters that can cause sea water intrusion.
  • The basic principle of this method was determination of vulnerability based on numerical system in weight and rating.
  • The weight was determined based on the significance of parameter influence to SWI, whereas rating was specified based on the significancy of variable effect of each parameter to the SWI.

Determination of Distance and Interface Depth

  • For the aquifer type the weight was 1, the aquifer hydraulic conductivity was 3, height of groundwater level was 4, distance from the shore was 4, the ratio of Cl-/[HCO3-+ CO32-] was 1, and for the aquifer thickness was 2.
  • It was estimated that the distance from the shoreline was dominant parameter in determining the groundwater vulnerability in the research area because its value was quite varied, and it was similar for the ratings.
  • Based on the rating of GALDIT index, the value range was entered in one category and was valued by 2.5.

Height Calculation of Groundwater Level from Mean Sea Level

  • The height of groundwater level from mean sea level is determined by the parameters i.e. specific discharge of groundwater, distance from shoreline, the density of freshwater and saline water, and the aquifer hydraulic conductivity.
  • The groundwater specific discharge of each observed wells is based on the calculating results in Table 5, freshwater density that is appropriate with the Law Ghyben-Herzberg is determined by 1.000 g/ cm3, whereas the density of saline water is determined by 1.025 g/cm3 (Todd & Mays, 2005).
  • The groundwater level with the height of 0.59 m was founded southern Cilacap village, whereas the groundwater level with the height of 3.05 m is existed in Gumilir village.
  • It could be said that the farther distance from the shoreline, the higher the groundwater level.
  • This statement is proved by graphic that showed in Figure 3.,.

Calculation of Freshwater Depth from Sea Level

  • The freshwater depth from saline water level is also determined by groundwater specific discharge, distance from the shoreline, density of freshwater and saline water, and aquifer hydraulic conductivity.
  • The calculating results showed that the region of South Cilacap located 300 m from the shoreline, had the most shallow groundwater depth, 24.59 m, whereas the region of Gumilir located 2000 m from the shoreline had the largest groundwater depth, 125.93 m.
  • This showed the tendency that the farther distance from the shoreline, the greater the depth of interface would be, and otherwise the closer distance from the shoreline, the swallower the depth of interface .
  • The completely results related to the calculation of groundwater depth from sea water level could be regarded in Table 7.

Vulnerability Relationship to SWI with Interface Depth

  • The results showed that in the research area had been detected interface with varied depths, ranging from 26.68 m in South Cilacap to 129.74 m in Gumilir.
  • This could be understood because of the community well had the depths that was not greater than 25 m.
  • There was a quite interesting phenomenon in the observed wells located in TegalKamulyan which had the distance of 500 m from the shoreline.
  • Compared with other areas of research, the groundwater specific discharge in the area was low, that was 0.40 m3/day.
  • Cases of deep well drilling that took place in Takome Village were a real example that the hydrological conditions of the northern part of Ternate Island were very vulnerable to SWI.

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Groundwater Vulnerability from Sea Water Intrusion in Coastal Area
Cilacap, Indonesia
Setyawan Purnama
Faculty of Geography, Universitas Gadjah Mada, Yogyakarta, Indonesia
Abstract e important issue relating to water resources is sea water intrusion (SWI) phenome-
na. Nowadays, the phenomena has become serious problem in the urban coastal area. Ground-
water as main sources for domestic usage cannot be used again because of its salinity.Cilacap
as one of urban coastal area also face the problem. In 1977 SWIwas detectedand experienced
signicant developmentsin 1996,is research was conducted to: (1) analyze agroundwater vul-
nerability to the SWI; (2) determine adistance and adepth theinterface; and (3) analyze relation-
ship of the groundwater vulnerability to the interface depth.It was performed an analysis of the
groundwater vulnerability to the SWI using the method of GALDIT, whereas the distance and
depth of the interface was determined using the method of DupuitGhyben-Herzberg. e link-
age analysis of the groundwater vulnerability to the depth of the actual interface was conducted
by quantitative descriptively.e results showed that the distance from the shoreline was the
most determined factor of the groundwater vulnerability to the SWI, the closer to the shoreline
the more swallow the depth of the interface. It existed the relevance between the vulnerability
level of groundwater to the SWI with the depth of actual interface. e regions with low level of
vulnerability had deep interface depth, whereas the regions with moderate level of vulnerability
had swallow interface depth. Nevertheless, the SWI has not yet aected the groundwater in
people wells because of its depth that was not yet exceeded of 25 m.so that this depth can be used
as a reference in digging wells in the research area++
Received: 2019-05-18
Accepted: 2019-07-29
Keywords:
groundwater vulnerability,
sea water intrusion,
coastal city,
Cilacap,
Indonesia
Corespondent Email:
Igiwan@ugm.ac.id
1.Introduction
Coastal is a contact area between land and sea.
Towards the land covers parts of the land, both dry and
submerged in water, which are still inuenced by the
characteristics of the sea such as tides, sea breezes, and
SWI, while towards the sea covers the part of the sea
which is still inuenced by natural processes. Because
of this location, coastal areas are vulnerable to various
problems such as SWI and tidal ooding.
Partly citiesin Java, Indonesia are located incoastal
area, such as:Jakarta, Cirebon, Pekalongan, Semarang,
and Surabaya are some of cities located on the northern
coast of Java, whereas Cilacap is located on the southern
one of Java Island. In general, coastal zone oen face
intensive pressures for development (Gwalema, 2011).
Beside it, urban areas in the coastal area have faster rate
of growth than the rural ones, marked by higher level
of population growth and the expansion of residential
areas.A greater growing number of people needs more
facilities and infrastructure, one of them is water
resources availability. It would aect to the greater
number of groundwater extraction, whereas in another
side it would be decreased the groundwater inow
because of the larger open land used for recharge area
was converted into residential area (Tillman & Leake,
2010; Fenta & Kie, 2014; Waikar & Nilawar, 2014).
e decreased number of groundwater would
eect to the decreased number of water pressure that
could cause penetration of saline water from sea into
the mainland (Pousa, et al., 2007; Marandi & Vallner,
2010). is phenomenon is called sea water intrusion
(SWI), whereas border between freshwater and saline
water is called interface (Young Kim, Suk Park, & Pyo
Kim, 2009; Basack, Bhattacharya, Sahana, & Maity,
2010; Rotzoll, et al., 2010). Beside that, recently SWI
was also driven by future sea level rise which result
to the increase of the fresh water front forward move
(Rahmawati, Vullaume, & Purnama, 2013). It could
be said that the SWI is problematic issue in the cities
located on the coastal regions, because it could make
quality changes of groundwater that could not be use
more as drinking water resource (Obikoya, 2010; Dayal
& Chauhan, 2010).
Some researchresults showed that it has been
detected an interface in Cilacap City. It turned out over
time the depth of interface in some places of the city
was changed. In 1996 it was found the existence of SWI
in some places that were not detected with it in 1977
(Simoen, Darmanto, & Darsomartoyo, 1977; Purnama,
Perkembangan intrusi air laut di Kota Administratif
Cilacap., 1996). Nevertheless, some places with
interface in 1977 and 1996 were not detected anymore
with it in 2013 (Purnama, et al., 2013). Related to this
Indonesian Journal of Geography Vol. 51 No. 2, August 2019 (206 - 216)
DOI: http://dx.doi.org/10.22146/ijg.44914
© 2019 by the authors.is article is an open access article distributed under the terms and conditions of the Creative
Commons Attribution(CC BY NC) licensehttps://creativecommons.org/licenses/by-nc/4.0
RESEARCH ARTICLE

Indonesian Journal of Geography, Vol. 51 No. 2, August 2019 : 206 - 216
207
problem, it has been continued the research of SWI in
the coastal area of Cilacap to get actual information
about the eects of distance from the shoreline to the
depth of interface in the researcharea.
Base on the background, the objectives of the
research are (1) analyze the groundwater vulnerability
to the SWI in the research area, (2) determine the
distance and the depth of the interface in the research
area, and (3) analyze the relationship of the groundwater
vulnerability to the interface depth.
2.e Methods
To nd out the relationship between groundwater
vulnerability fromSWI and distance from shoreline and
interface depth two method were used, namely GALDIT
method and Dupuit Ghyben-Herzberg principle
With the GALDIT, it can be seen the environmental
condition of a place related to its vulnerability including
the distance from the shore line, whereas with the
Dupuit Ghyben-Herzberg, the depth of the interface
can be known at a certain distance on the shore line.
e GALDIT method has been successfully uses to
asses groundwater vulnerability from SWI in the
Portuguese aquifer system of Monte Gardo (Lobo-
Ferreira, Chachadi, Diamantino, & Henriques, 2005)
and the Bardez aquifer in Goa India (Chachadi & Lobo-
Ferreira, 2005).
Determination of Groundwater Vulnerability
It was conducted a research using GALDIT method
to get the information about groundwater vulnerability
fromSWI. GALDIT stands for parameters that can
cause sea water intrusion. G is dened as groundwater
occurrence, A is dened as aquifer hydraulic
conductivity, L is dened as level of groundwater above
mean sea level, D is distance from the shore, I as impact
of existing status of SWI and T is thickness of aquifer
being mapped (Chachadi & Lobo-Ferreira, 2005).
e basic principle of this method was
determination of vulnerability based on numerical
system in weight and rating. e weight was determined
based on the signicance of parameter inuence to SWI,
whereas rating was specied based on the signicancy
of variable eect of each parameter to the SWI. Weight
and rating of each GALDIT parameter and variable is
shown in Tables 1 and 2.
Determination of Distance and Interface Depth
eoritically, the groundwater ow in the coastal
aquifer could be explained through the combination of
Dupuit equation and Ghyben-Herzberg principle such
as the following (Fetter, 2001) :
z=Gq/K+√(2Gqx/K) ..…………................................(2)
by q is the specic discharge of groundwater per unit of
wide in m3/day/m, x is shoreline distance to the point
of the determined land and K is hydraulic conductivity
that determined by Morris and Johnson criteria (Todd
& Mays, 2005). e specic discharge of groundwater
could be calculated by using the method of Darcy
(Rushton, 2003; Davie, 2008):
q=K.A.dh/dl ……………......................................(3)
by dh/dl is hydraulic gradient.
e heigh of freatic level from sea water level in
each distance of x and the depth of z interface could be
determined using the following equation (Fetter, 2001) :
h=√(2qx/GK) ....….………...........................(4)
To validate the calculated results, it could be
conducted a measurement of electrical conductance in
the observed well. If the electrical conductance is less
than 1500 µmhos/cm, it could be said that the observed
well is not yet inuenced by the saline water. Likewise,
if the level of chloride is less than 150 mg/l, it could be
said for the same condition of the observed well.
3.Result and Discussion
Groundwater Vulnerability
As explained before, therewere six types of
parameters used to calculate the index of GALDIT i.e.
aquifer hydraulic conductivity, height of groundwater
level, distance from the shoreline, ratio of Cl-/ [HCO3-
+ CO32-], and thickness of aquifer. Because of the
dierent inuence of each parameters in saline water
intrusion, the weight was also dierent. For the aquifer
type the weight was 1, the aquifer hydraulic conductivity
was 3, height of groundwater level was 4, distance from
the shore was 4, the ratio of Cl-/[HCO3-+ CO32-] was
1, and for the aquifer thickness was 2.
Result determinant of rating of each parameter
indicated that based on the composition of rock
layering of the data drilling, there was only one types of
aquifers in the research area that is unconned aquifer,
so that the same value of the rating was 7.5. Related
to the aquifer constituent rocks, all of them have sand
textured so that the aquifer hydraulic conductivity was
also 7.5.
It was quite varied for the height of groundwater
level in the sea level. Nevertheless, almost all had
categories of more than 2 meters of mean sea level, so
that it valued of 2.5. Only one observed wells which
had the groundwater level between 1.5-2 m of mean sea
level and 5 in value.
It was estimated that the distance from the
shoreline was dominant parameter in determining the
groundwater vulnerability in the research area because
its value was quite varied, and it was similar for the
ratings. e results of rating determination showed
that the parameter of distance from the shoreline varied
from 2.5 to 10.
Giving attention to the ratio value of Cl-/[HCO3-
+ CO32-], it was known that the groundwater in
observed wells had value between 0.13 to 0.33. Based
on the rating of GALDIT index, the value range was
entered in one category and was valued by 2.5. It was
also existed for the parameters of the aquifer thickness
that ranged from 11.39 to 17.55 m. Based on the ratings

GROUNDWATER VULNERABILITY FROMSEA Setyawan Purnama
208
of GALDIT index, the range value was entered in one
category thickness level with the value of 10.
Furthermore, based on the ratings of each
parameter it could be calculated the GALDIT index
for each observed well. e calculations showed that
there were eight observed wells with the GALDIT index
of 4.8, two observed wells with the GALDIT index
of 5.5, and seven observed wells with the GALDIT
index of 6.8. Viewed from the vulnerability level,
eight observed wells were belonged to the level of low
vulnerability and nine observed wells were belonged
to the moderate vulnerability. It is regarded from
the spreading, generally the observed wells with the
moderate vulnerability level were located at the closer
distance from the shoreline, whereas the observed wells
with the low level of vulnerability were located further
away from the shoreline. Based on this data (Table 4),
it could be created a Groundwater Vulnerability Map of
saline water intrusion in the research area as shown in
Figure 1.
Table2. Ratingsfor parameteraquifer hydraulic conductivity, height of groundwater level above sea level,
distance from the shoreline, ratio of Cl-/[HCO3-+CO32-], and thickness of aquifer
Indicator Variable
Indicator Weights Vulnerability
Class Range Rating
Aquifer hydraulic conductivity (m/day) 3 High >40 10
Medium 10-40 7.5
Low 5-10 5
Very low <5 2.5
Height of groundwater level above sea
level(m)
4 High <1 10
Medium 1-1.5 7.5
Low 1.5-2 5
Very low >2 2.5
Distance from the shoreline(m) 4 Very small <500 10
Small 500-750 7.5
Medium 750-1000 5
Far >1000 2.5
Ratio of Cl-/[HCO3-+CO32-] (epm) 1 High >2 10
Medium 1.5-2 7.5
Low 1-1.5 5
Very low <1 2.5
ickness of aquifer (m) 2 Large >10 10
Medium 7.5-10 7.5
Small 5-7.5 5
Very small <5 2.5
Source : Chachadi A.G. & Lobo-Ferreira, J.P. 2005
Table 1. Rating forparameter aquifer type
Indicator Weight Indicator Variable Vulnerability Rating
Aquifer Type 1 Conned Aquifer 10
Unconned Aquifer 7.5
Semi-Conned Aquifer 5
Bounded Aquifer 2.5
Source : Chachadi A.G. & Lobo-Ferreira, J.P. 2005
Table3. GALDIT vulnerability classes
Index Range of GALDIT Vulnerability Classes
>7.5 High vulnerability
5-7.5 Moderate vulnerability
<5 Low vulnerability
Source : (Chachadi & Lobo-Ferreira, 2005)

Indonesian Journal of Geography, Vol. 51 No. 2, August 2019 : 206 - 216
209
Table 4. Calculation of GALDIT index and vulnerability classes
Number of
Observed
Well
Aquifer Type
Hydraulic Conductivity Height of Groundwater
Level
Distance from the Shore Ratio of Cl-/[HCO3-
+CO32-]
Aquifer ick-
ness
Index of
GALDIT
Vulner-
ability
Classes
Rating Weight Value Rating Weight Value Rating Weight Value Rating Weight Value Rating Weight Value Rating Weight Value
1 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
2 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
3 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
4 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
5 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
6 7.5 1 7.5 7.5 3 22.5 2.5 4 10 10 4 40 2.5 1 2.5 10 2 20 6.8 Moderate
7 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
8 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
9 7.5 1 7.5 7.5 3 22.5 5.0 4 20 7,5 4 30 2.5 1 2.5 10 2 20 6.8 Moderate
10 7.5 1 7.5 7.5 3 22.5 2.5 4 10 5,0 4 20 2.5 1 2.5 10 2 20 5.5 Moderate
11 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
12 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
13 7.5 1 7.5 7.5 3 22.5 2.5 4 10 5,0 4 20 2.5 1 2.5 10 2 20 5.5 Moderate
14 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
15 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
16 75 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low
17 7.5 1 7.5 7.5 3 22.5 2.5 4 10 2,5 4 10 2.5 1 2.5 10 2 20 4.8 Low

GROUNDWATER VULNERABILITY FROMSEA Setyawan Purnama
210
Regarding to the Groundwater Vulnerability Map
of saline water intrusion that is shown in Figure 1, it
could be said that the distance from the shoreline
was the most determined factor of the groundwater
vulnerability to the saline water intrusion in Cilacap
coastal area. e closer area to the shoreline has a
higher vulnerability to the saline water intrusion than
the farther area.
Calculation of Specic Discharge
In this research, it was conducted the calculation
of specic discharge at all observed wells in accordance
with the path of groundwater ow in the ownet. Such
as explained in research methods, the equations used in
the calculation was the general equation of groundwater
ow from Darcy.
In accordance with this equation, calculation of
groundwater specic discharge needed some data i.e.
aquifer hydraulic conductivity, aquifer cross-sectional
area, and hydraulic gradient. e value of aquifer
hydraulic conductivity is determined based on drilling
data, which are located closest to the observed wells.
In the area of research there are three data drillings
i.e. villages of Cilacap, Sidanegara, and Tambakreja.
Considering to the constituent material of the aquifer,
the three sites of drilling are composed of sand with
varied colors i.e. brown and yellow sand at the top,
and black and gray sand on the bottom. Based on the
Morris and Johnson criteria (Todd & Mays, 2005), the
hydraulic conductivity value of sand is 12 m/day.
Figure 1. Groundwater Vulnerability Map fromSWI in the research area

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Abstract: Besides being able to cause land subsidence, excessive groundwater use in coastal areas can also cause to sea water intrusion. The purpose of this study is to evaluate the use of groundwater in the study area in relation to its vulnerability to sea water intrusion. Because groundwater in the study area is used for domestic, industry and livestock purposes, the water use that is taken into account is the use of water for the three sectors. The amount of water used for domestic purposes is calculated based on the population and the amount of water needed of each person per day. The amount of water use for industry is calculated based on the number of industrial employees and water usage of each employee per day. Water use for livestock is calculated based on the number of livestock and water use of each livestock per day. The results of this water usage calculation are then linked to the criteria for groundwater vulnerability to sea water intrusion and the depth of the interface. Observing the relationship between groundwater usage and the vulnerability of groundwater to sea water intrusion and the depth of its interface, Tegal Kamulyan, Cilacap and Sidakaya villages, all of which are located in South Cilacap District, need attention. The three village are classified as moderate vulnerability to sea water intrusion and shallow interface depth, but their water usage is quite high. For this reason, it is necessary to make efforts to find other water sources for domestic, industry and livestock requirement other than groundwater.

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01 Jan 2021
Abstract: The existence of groundwater in coastal areas really needs attention because of its vulnerability to sea water intrusion. Utilization and good management are needed to maintain its sustainability. The purpose of this research is to determine the aquifer system in the study area and to calculate the groundwater potency. The aquifer system is determined by processing geoelectric sounding data using Rockworks 16 software. Groundwater potency is calculated using a static approach. The safe yield of groundwater is calculated by multiplying of groundwater fluctuation, village area and the specific yield. Water requirement is calculated base on domestic, livestock and tourism water requirement. The results showed that the Kretek District had two aquifer units, namely the fluvio marin plains and sand dunes. In the fluvio marin plains, most of the constituent material is sand with clay as inserts, while in the aquifer unit the sand dune has constituent material in the form of unconsolidated sand originating from the Merapi Volcano. The groundwater potency of the study area is 234,448,0000 m3 /year and the safe yield is 11,772,400 m3 /year. With the water requirement for domestic, livestock and tourism are 555,044 m3 /year, the groundwater potency in the study area is still sufficient. However, it is recommended that the well drilling does not exceed a depth of 40 meters, because at several locations there has been detected an interface. In addition, in several locations there were also detected connate water originating from ancient marines during the deposition process of the fluvio marin plains in the past.

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References
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Book
01 Jan 2003
Abstract: Preface1 IntroductionPART I: BASIC PRINCIPLES2 Background to Groundwater Flow3 Recharge due to Precipitation or Irrigation4 Interaction between Surface Water and GroundwaterPART II: RADIAL FLOW5 Radial Flow to Pumped Boreholes - Fundamental Issues6 Large Diameter Wells7 Radial Flow where Vertical Components of Flow are Significant8 Practical Issues of Interpretation and Assessing ResourcesPART III: REGIONAL GROUNDWATER FLOW9 Regional Groundwater Studies in which Transmissivity is Effectively Constant10 Regional Groundwater Flow in Multi-Aquifer Systems11 Regional Groundwater Flow with Hydraulic Conductivity Varying with Saturated Thickness12 Numerical Modelling InsightsAppendix: Computer Program for Two-zone ModelList of SymbolsReferencesIndex

180 citations


"Groundwater Vulnerability from Sea ..." refers methods in this paper

  • ...The specific discharge of groundwater could be calculated by using the method of Darcy (Rushton, 2003; Davie, 2008): q=K.A.dh/dl ……………......................................(3) by dh/dl is hydraulic gradient....

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  • ...Such as explained in research methods, the equations used in the calculation was the general equation of groundwater flow from Darcy....

    [...]

  • ...The specific discharge of groundwater could be calculated by using the method of Darcy (Rushton, 2003; Davie, 2008): q=K....

    [...]


Book
15 Nov 2002
Abstract: 1. Hydrology as a Science 2. Precipitation 3. Evaporation 4. Storage 5. Runoff 6. Streamflow Analysis and Modelling 7. Water Quality 8. Water Resource Management in a Changing World. Glossary. References. Index

179 citations


"Groundwater Vulnerability from Sea ..." refers methods in this paper

  • ...The specific discharge of groundwater could be calculated by using the method of Darcy (Rushton, 2003; Davie, 2008): q=K.A.dh/dl ……………......................................(3) by dh/dl is hydraulic gradient....

    [...]

  • ...Such as explained in research methods, the equations used in the calculation was the general equation of groundwater flow from Darcy....

    [...]

  • ...The specific discharge of groundwater could be calculated by using the method of Darcy (Rushton, 2003; Davie, 2008): q=K....

    [...]


Journal ArticleDOI
Abstract: Sustainable development and management of groundwater resources require application of scientific principles and modern techniques. An integrated approach is implemented using remote sensing and geographic information system (GIS)-based multi-criteria evaluation to identify promising areas for groundwater exploration in Raya Valley, northern Ethiopia. The thematic layers considered are lithology, lineament density, geomorphology, slope, drainage density, rainfall and land use/cover. The corresponding normalized rates for the classes in a layer and weights for thematic layers are computed using Saaty’s analytical hierarchy process. Based on the computed rates and weights, aggregating the thematic maps is done using a weighted linear combination method to obtain a groundwater potential (GP) map. The GP map is verified by overlay analysis with observed borehole yield data. Map-removal and single-parameter sensitivity analyses are used to examine the effects of removing any of the thematic layers on the GP map and to compute effective weights, respectively. About 770 km2 (28 % of the study area) is designated as ‘very good’ GP. ‘Good’, ‘moderate’ and ‘poor’ GP areas cover 630 km2 (23 %), 600 km2 (22 %) and 690 km2 (25 %), respectively; the area with ‘very poor’ GP covers 55 km2 (2 %). Verification of the GP map against observed borehole yield data shows 74 % agreement, which is fairly satisfactory. The sensitivity analyses reveal the GP map is most sensitive to lithology with a mean variation index of 6.5 %, and lithology is the most effective thematic layer in GP mapping with mean effective weight of 52 %.

90 citations


"Groundwater Vulnerability from Sea ..." refers background in this paper

  • ...It would affect to the greater number of groundwater extraction, whereas in another side it would be decreased the groundwater inflow because of the larger open land used for recharge area was converted into residential area (Tillman & Leake, 2010; Fenta & Kifle, 2014; Waikar & Nilawar, 2014)....

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Journal Article
Abstract: Groundwater is an important resource contributing significantly in total annual supply. However, overexploitation has depleted groundwater availability considerably and also led to land subsidence at some places. Assessing the potential zone of groundwater recharge is extremely important for the protection of water quality and the management of groundwater systems. Groundwater potential zones are demarked with the help of remote sensing and Geographic Information System (GIS) techniques. In this study a standard methodology is proposed to determine groundwater potential using integration of RS & GIS technique. The composite map is generated using GIS tools. The accurate information to obtain the parameters that can be considered for identifying the groundwater potential zone such as geology, slope, drainage density, geomorphic units and lineament density are generated using the satellite data and survey of India (SOI) toposheets of scale 1:50000. It is then integrated with weighted overlay in ArcGIS. Suitable ranks are assigned for each category of these parameters. For the various geomorphic units, weight factors are decided based on their capability to store groundwater. This procedure is repeated for all the other layers and resultant layers are reclassified. The groundwater potential zones are classified into five categories like very poor, poor, moderate, good & excellent. The use of suggested methodology is demonstrated for a selected study area in Parbhani district of Maharashtra. This groundwater potential information will be useful for effective identification of suitable locations for extraction of water.

71 citations


Journal ArticleDOI
Abstract: The Buenos Aires (Argentina) and Venice (Italy) coastlands have experienced significant saltwater contamination of the phreatic aquifer, coastal erosion, hydrodynamic changes and relative sea level rise processes due to natural and man-induced factors. These factors expose coastal areas to morpho-hydro-geological hazards, such as soil desertification, frequency and degree of flooding, littoral erosion, and the silting of river mouths and channels. Man-made interventions and actions, such as beach mining, construction of coastal structures and exploitation of aquifers without an adequate knowledge of the hydrology setting and an adequate management program, worsen these natural hazards. Uncontrolled human activity induces environmental damage to the overall coastal plains. The coastal plains play an important role in the social/economic development of the two regions based on land use, such as agriculture, horticulture, breeding, and tourism, as well as industry. Results of investigations on saltwater contamination, sea level rise and morphological changes recently performed in these two coastal areas are presented here.

47 citations


Frequently Asked Questions (1)
Q1. What contributions have the authors mentioned in the paper "Groundwater vulnerability from sea water intrusion in coastal area cilacap, indonesia" ?

In 1977 SWIwas detectedand experienced significant developmentsin 1996, This research was conducted to: ( 1 ) analyze agroundwater vulnerability to the SWI ; ( 2 ) determine adistance and adepth theinterface ; and ( 3 ) analyze relationship of the groundwater vulnerability to the interface depth. Nevertheless, the SWI has not yet affected the groundwater in people wells because of its depth that was not yet exceeded of 25 m. so that this depth can be used as a reference in digging wells in the research area++