ISSN 1979-4835
E-ISSN 2721-2335
ANALYSIS OF THE EFFECTS OF RAINFALL.
LAND USE CHANGES,
AND AMOUNT OF WATER USAGE ON GROUNDWATER LEVEL
DECREASING (STUDY IN GEDEBAGE)
Muhammad Hafidh Alhaq1.
Bakhtiar Abu Bakar2.
Didin Kusdian3 Universitas Sangga Buana YPKP.
Bandung Dosen Universitas Sangga Buana YPKP.
Bandung Dosen Universitas Sangga Buana YPKP.
Bandung Email : hafidh.
alhaq@gmail.
com (Universitas Sangga Buana YPKP) ABSTRAK Sustainable urban development has been one of the main concerns for policy-makers.
Increasing rate of population and urbanization have resulted in several socio-environmental impacts on people.
Hence, water resources management in cities, as one of the most vital strategies, has become more complicated and In this study, the impact of precipitation, land-use changes, and amount of groundwater usageon groundwater level fluctuations was assessed.
Using precipitation, remote sensing maps data from satellites, data of groundwater level, and land-use was extracted and processed by different formula and mapping tools.
Gedebage Area in Bandung.
Indonesia was selected as the case study location.
The potential impacts of urban development in this city on groundwater resources were studied.
The results suggest that from 2014 to 2018.
Groundwater level decreasion was to increase simultaneously with run off discharge.
Society perception confirmed that 95% is affected by precipitation, landuse change and amount of water usage at significance <0.
05 while this change rate was more intense during previous decades and is predicted to be increased by Since relationship between precipitation, land-use change and amount of groundwater usage on groundwater level decreasion is undeniable, novel methodology of this stsudy can be employed for other fastgrowing cities in Indonesia.
surface water and ground water.
Essentially INTRODUCTION According to regulation No.
SDA 7 of 2004, water resources management is an effort to plan, fulfill, monitor, and evaluate the implementation of water resources conservation, water resources utilization, and water damage control.
There are two main components of water resources, surface water and groundwater.
Surface water and river area management are the basic concepts that contain one or more Integrated water resources there is a relationship between surface occurrence of groundwater supply in surface water, and surface water can also conditions .
Water is an important natural resources has unique characteristics compared to other Water is a renewable and dynamic resource.
This means that the main source of water in the form of rain always come in accordance with the time or season throughout the year.
However, in Jurnal Techno-Socio Ekonomika.
Volume 13 No.
1 April 2020
Universitas Sangga Buana YPKP
ISSN 1979-4835
E-ISSN 2721-2335
certain conditions water can be non-
MATERIALS AND METHOD
Study Area geological conditions where the process of The study is located in Gedebage District, ground water travel takes thousands of Bandung City.
Indonesia.
The Gedebage years, so that when excessive groundwater District is designated as a Gedebage City is extracted, water will run out.
Therefore.
Sub-Region based on the 2011-2031 it is not an exaggeration to say by Pindar Bandung City Spatial Plan.
It has a total "Woter is the best of all things.
" Life is a area of 9.
80 km2.
Gedebage is a floodplain gift from God, the existence of life is due area due to the low terrain, which has an to the presence of water.
Maintaining the average land surface elevation of 665 m existence of water in a sustainable manner, above sea level.
Other areas in the we also maintain life, which means also Bandung City has an average elevation of maintain God's grace .
Kodoatie, 2012 700 m above sea level which caused water stated the flow to the river is slow in Gedebage Area, process of ground formation is caused by the process of water hence being prone to flooding.
infiltration on the ground surface that Gedebage The District land-use percolation automatically occurred when decreasing groundwater level modeling.
the water content in the unsaturated zone Precipitation continues to increase from reaches the field capacity because of year to year.
One of the factors is the gravity that lead to the saturated zone.
global climate change phenomenon.
The take ground water with a large enough development is also increased in line with amount, for example in industry, the most used method is to make deep wells which Gedebage Primary Center, where there are are generally made of pipes to exploit deep a variety of important facilities on a large ground water .
Regional spatial planning is to improve and develop socio-economic In general, spatial planning prioritizes spatial and economic values.
This phenomenon causes changes while environmental values are ignored .
in land use and increased demand for clean Jurnal Techno-Socio Ekonomika.
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Data Description statistical parameters of the probability of Data sources are divided into two, namely rainfall distribution using the Gumbel, primary data and secondary data.
Primary normal, normal log, and Pearson log type 3 data is obtained by questionnaire.
The methods .
The study of land use change sample size approach in most ex post facto was carried out using remote sensing studies and experimental samples totaling 30 or more is highly recommended .
The identification of land use Whereas secondary data is obtained from change maps is carried out using the 2014- the records and documentation of the 2018 land use map overlapping process government agency.
Obtained secondary .
he results of digitizatio.
with UTM data is in the form of precipitation, land- (Universal use change, and groundwater level data.
Image contrast improvement Precipitation data is obtained from two through histogram alignment is done by stations around the Gedebage District, supervised classification techniques which Cibiru and Gedebage rain posts.
Landuse are divided into 4 .
classes, namely change data is obtained from the digitized rice fields, settlements, vegetation, and Groundwater level data was obtained ordinary land .
from The Energy and Mineral Resources Run-off is the part of rainfall that flows Agency of West Java.
above the land surface towards a larger Transverse Mercato.
body of water.
Run-off is a small portion of Data Analysis Precipitation intensity, duration, depth, and frequency.
Intensity related to duration and frequency can be expressed with Intensity Duration Frequency (IDF) curves.
IDF curves are obtained by finding suitable distribution types from precipitation data.
The annual maximum daily precipitation data for 10 years of observation was used to find the pattern of rainfall distribution through rainfall that moves above the surface or through land to surface water features .
Estimation run-off important for designing soil conservation structures with adequate capacity.
Peak run-off can be estimated using the Rational method, where total run-off is calculated using the Curve Number Method.
The Rational Method is the most method Jurnal Techno-Socio Ekonomika.
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widely used for estimating peak run-off Inferential statistics produce analytical which is quite accurate .
results which are presented by frequency The rational method .
is the most distribution tables, line graphs, bar graphs, common method for estimating peak run- piecharts , and pictograms.
Discussion is an off in small watersheds .
ess than 1,300 in-depth explanation and interpretation of on the the data that has been presented .
The assumption that .
rainfall occurs at a steps taken are testing the normality of the uniform intensity for a certain duration at least the same time as the watershed regression analysis.
To draw conclusions concentration, and .
rainfall occurs at a the significance level of 5% ( = 0.
is uniform intensity throughout the watershed used, meaning that if the null hypothesis is Run-off discharge (Q.
can be rejected .
with a 95% confidence calculated using the formula:
level, then it is likely that the results of This drawing conclusions have a truth of 95% Qp = 0.
0278 CIA.
and this indicates the presence/ absence Where Q = peak runoff velocity .
3 / .
C convincing influence .
between = runoff coefficient.
I = rainfall intensity these two variables.
The significance for the same duration as the concentration results are used to clarify the results of time, .
m / hou.
, and A = watershed area mathematical calculations how much the .
influence of rainfall, land use changes, and Land-use changes maps are used to amount of groundwater usage affect the calculate the amount of run-off over the groundwater levels.
last 5 years.
groundwater level water
changes was analyzed by inputting UTM
RESULTS AND DISCUSSION
coordinate data from monitoring well Intensity Duration Frequency Analysis which hava locations and groundwater The type of distribution that meets the level elevation data.
XYZ tabular data was requirements was Log Pearson Type i.
inputted on a three-dimensional grid which We used the compatibility test of the distribution with 2 methods.
To test the dimensional contours and surfaces.
suitability of a distribution distribution used the Chi Square Test .
From the Jurnal Techno-Socio Ekonomika.
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ISSN 1979-4835
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Chi-Square test, the Chi-Square Count was amount of data n = 11 is 0.
39122 at the 18, while the Chi-Square Table .
significance of alpha 5%.
Because the 28 with 1% alpha.
Because Chi- calculated D value is smaller than the D Square count <Chi-Square table .
286 <0.
, the distribution <13.
then the data can be received.
Whereas with Smirnov-Kolmogorov.
The Intensity Duration Frequency Curve is calculation results show the valueof Dmax shown in Fig 1.
= 0.
while the value of D table at the Fig 1.
Curves of intensity, duration, and frequency of precipitation Land-use Changes Analysis coordinates methods.
Digitization results Land-use change was analyzed by the GIS (Geographic Information Syste.
method indicate differences in land-use Fig.
Fig.
digitized on the last 5 years maps.
Taking 2.
Fig.
Fig.
Fig.
the digitization area picture process used the historical method for different colors is recapitulated in the on google earth after streaming 100% table then becomes the data to calculate the image data which will be digitized.
Image surface peak runoff.
georeferencing was obtained by UTM Jurnal Techno-Socio Ekonomika.
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Fig 2.
Land-Use in Gedebage Area in 2014 Fig 3.
Land-Use in Gedebage Area in 2015 Fig 4.
Land-Use in Gedebage Area in 2016 Jurnal Techno-Socio Ekonomika.
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Fig 5.
Land-Use in Gedebage Area in 2017 Table 1 Area Value of Changes in Land-Use for 2014-2018 Years (H.
Land-Use Soil Ground 278.
Vegetation Field Building Run-Off Analysis Naturally some of the rainwater that falls to the ground surface will seep into the ground and the rest will flow into surface The condition of the area where the rain falls will greatly affect the part of the rain that will seep into the ground and will Jurnal Techno-Socio Ekonomika.
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This means that environment have an influence on the hydrological response.
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The results showed an increment in runoff period an increase in runoff discharge by discharge over the five years from 2014- an average of 4% per year.
2018 using rational method.
During this Table 2 The amount of runoff discharge for the 2014-2018 period.
Year Runoff Discharge .
The impact of surface runoff due to Groundwater volume and decreassion changes in land use increases then at the same time will reduce water infiltration to Topographic map is a map that has the ground.
Factors affecting run-off information about the surface height at a discharge are infiltration, the amount of place that is drawn with contour lines.
The water retained by vegetation and a basin topographic information contained on a that results in inundation.
If the run-off is topographic map can be used to create a large then the infiltration is small, while the three-dimensional model of a surface.
With run-off is low then the infiltration is high.
the three-dimensional model the objects on This low run off causes the rainwater not to the map are seen as more alive as they enter the ground so that it affects the really are in nature, so to analyze a groundwater level.
topographic map can be more easily done.
To calculate the volume of groundwater a 3-dimensional model of groundwater contour was required.
Jurnal Techno-Socio Ekonomika.
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Fig 7.
Gedebage Groundwater level in 2014 Fig 8.
Gedebage Groundwater level in 2018 Effects of rainfall, changes in land use and amount of groundwater usage on the decreassion in groundwater level.
A model of the level of groundwater linear regression which estimates the reduction in groundwater obtained from rainfall, changes in land cover, and the amount of groundwater use for the purpose of efficient management of groundwater resources in Gedebage Area.
Bandung.
Jurnal Techno-Socio Ekonomika.
Volume 13 No.
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Through the application of the linear regression model, estimation of runoff from rainfall and estimation of water level parameters (Ground Water Dept.
obtained from monitoring well monitoring are revised to produce a decrease model.
The amount of influence analyzed from the model based on the estimated parameters of the predictor model .
ainfall, change in land cover, amount of water us.
evaluated gives a coefficient of determination (R.
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The results obtained confirm the application of multiple linear regression reliability and accuracy of the proposed models provides an estimate of 23%/ year model in the estimation of the rate of for the rate of decline in groundwater.
Height .
Below Gound Surfac.
decline and predictions in the area.
The 60,00 50,00 40,00 RA = 0,7184 30,00 20,00 10,00 0,00 2014 2016 2018 2020 2022 2024 2026 2028 2030 Years Fig 9.
Goundwater Level Trend with Multiple Regression Prediction Regression models to predict decreassion The study model used inferential methods groundwater level through 2030 have been by drawing conclusions based on fewer created based on these results Fig.
This sample data into more general conclusions regression model can serve as a scientific for a population.
Inferential research is basis for the management and exploration needed in this study so that to be more of groundwater resources in the Gedebage efficient research is carried out by taking a Area.
This approachment provided a new smaller number of samples from the method for determining the level of existing population.
In this inferential groundwater decreassion due to runoff.
research, a prediction is made.
Inferential This technique was expected to be able to provide alternatives as a prediction method The earliest assumption that for decreasing ground water level in certain must be met is that the sample is taken randomly from the population.
This is Community Groundwater Perceptions Level Decreassion GedebageArea Analysis.
necessary because inferential statistics there needs to be a sample from the Other assumptions that need to be met follow the analysis tools used.
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Table 3 Significance value of variable Variable Significance Precipitation Land-use Groundwater Usage Statistical analysis methods used in this indicated that there had been a change Regression Analysis.
Hypothesis testing of land use in the study area, namely in the Gedebage of 20.
9% from 2014 to T-test.
ANOVA.
The analysis of land use changes significant effect with <0.
05 with the 2018 with an average change of 4%.
magnitude of the influence of 95.
4% on the Groundwater contour analysis showed decrease in groundwater level.
that there had been a change in groundwater level elevation which had CONCLUSIONS caused a reduction in groundwater This study analyzes the effect of rainfall, changes in land use and volume of 621 Million Cubic.
groundwater use in the Gedebage sub- The direct effect of precipitation, land- district and applies a hydrological and statistical calculation model to simulate the magnitude of groundwater subsidence and groundwater level decreassion was investigate future projected trends.
This summarized as follows.
Considering influence, it indicates that the possibility of The analysis of runoff showed that a decline in the future is very large.
there was an increment every year from using the same method this type of analysis 2014 to 2018 of 21.
3%, from 35.
69 m3 is expected to be made more reliable and /sec to 43.
29 m3 /sec with an average used to support decision making, for increment of 4% per year.
example in city development strategies and environmental preservation.
Jurnal Techno-Socio Ekonomika.
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ISSN 1979-4835
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Acknowledgements This study was a part of a magister research study in SanggaBuana University.
Bandung.
Indonesia.
I would like to express my special thanks of gratitude to my teacher Dr.
Ir.
Bakhtiar Abu Bakar.
MT, (II) Dr.
Ir.
DidinKusdian.
MT who gave me the golden opportunity to do this study, which also helped me in doing a lot of Research and I came to know about so many new things I am really thankful to Secondly I would also like to thank my parents and friends who helped me a lot in finalizing this project within the limited time frame.
Thanks to Gedebage people who gave perception data for statistical All the observed data were provided by the Department of Energy and Meteorology (BMKG).
Bandung and we thanks to them Thanks to reviewers for their valuable REFERENCES