PEMETAAN TINGKAT KEKRITISAN DAERAH RESAPAN AIR DI KECAMATAN GUNUNGPATI BAGIAN UTARA KOTA SEMARANG
ghenady septio, Dr.Eng. Ir. Wawan Budianta, S.T., M.Sc.,IPM;Dr.Eng. Ir. Lucas Donny Setijadji, S.T., M.Sc., IPU
2024 | Tesis | S2 Teknik Geologi
Pesatnya pertumbuhan penduduk
di abad ke-21 salah satunya disebabkan urbanisasi. Dari urbanisasi berdampak
terjadinya Perubahan alih fungsi lahan karena pesatnya pembangunan
infrastruktur dan pemukiman yang menuntut adanya ketersediaan lahan. Hal ini
menyebabkan terjadinya degradasi lahan yang dapat terjadinya kurangnya tingkat
air meresapkan ke dalam tanah pada saat hujan. Dari kondisi ini dilakukan
penelitian tentang tingkat kekritisan daerah resapan air pada Kecamatan
Gunungpati bagian utara, guna mengetahui kondisi kawasan resapan air hujan yang
berada pada Kecamatan Gunungpati bagian utara. Penelitian ini menggunakan 5
parameter berupa tata guna lahan, laju infiltrasi, kemiringan lereng, litologi,
kedalaman muka air tanah. semua data parameter tersebut diolah menggunakan dua
metode Analytical Hierarchy Process dan Permen LHK No. 10 Tahun 2022
dari hasil dua metode tersebut akan didapatkan peta tingkat kekritisan daerah
resapan air kecamatan Gunungpati bagian utara yang kemudian nanti akan
dibandingkan dua metode tersebut dengan cara verifikasi kelapangan dan
menggunakan analisis Receiver Operating Characteristic (ROC). Tata guna
lahan yang memiliki laju infiltrasi cepat berupa hutan dan Perkebunan sekitar
35 %, laju infiltrasi yang memiliki laju infiltrasi sedang sekitar 19 %,
kemiringan lereng curam-sangat curam sekitar 24%, litologi penyusun yang
memiliki potensi permeabilitas tinggi adalah endapan aluvium dengan pasir –
krakal 2%, satuan batupasir sisipan konglomerat 16?n kedalaman muka air
tanah yang memiliki kemampuan meresapkan air paling tinggi adalah kedalaman 10m
- 20m sekitar 55%. Maka dari hasil tersebut didapatkan data luas zona tingkat
kekritisan resapan air pada 2 metode tersebut adalah metode AHP didapatkan
hasil luas kondisi daerah setiap klasifikasi tingkat kekritisan resapan air
dengan kondisi baik 2,53 km2 dengan persentase 9%, normal alami 2,78
km2 dengan persentase 10%, mulai kritis 6,43 km2 dengan
persentase 23%, agak kritis 10,48 km2 dengan persentase 38%, kritis
5,36 km2 dengan persentase 19%, sangat kritis 0,35 km2
dengan persentase 1%. metode Permen LHK No 10 tahun 2022 didapatkan hasil luas
kondisi daerah setiap klasifikasi tingkat kekritisan resapan air dengan kondisi
baik 1,85 km2 dengan persentase 7%, normal alami 6,45 km2
dengan persentase 23%, mulai kritis 10,14 km2 dengan persentase 36%,
agak kritis 7,14 km2 dengan persentase 26%, kritis 2,14 km2
dengan persentase 8%, sangat kritis 0,35 km2 dengan persentase 1%.
Hasil perbandingan dari kedua metode Analytical
Hierarchy Process dan metode Permen
LHK No tahun 2022 dengan menggunakan validasi Area Under Curve
(AUC) dengan nilai metode AHP 0,725 masuk
kategori Fair Classification dan metode Permen LHK No tahun 2022 dengan
nilai performa 0,624 masuk kategori poor classification. Maka dari hasil
validasi Area Under Curve (AUC) dapat disimpulkan bahwasanya
metode AHP lebih baik dari metode Permen LHK No 10 tahun 2022.
One of the reasons for rapid population growth in the 21st century
is urbanization. Urbanization has the impact of changes in land use due to the
rapid development of infrastructure and settlements which demands land
availability. This causes land degradation which can result in a decrease in
the level of water seeping into the soil when it rains. From this condition,
research was carried out on the criticality level of water catchment areas in
the northern part of Gunungpati District, in order to determine the condition
of rainwater catchment areas in the northern part of Gunungpati District. This
research uses 5 parameters in the form of land use, infiltration rate, slope
slope, lithology, depth of ground water table. All parameter data is processed
using two methods Analytical Hierarchy Process and Minister of Environment and
Forestry Regulation No. 10 of 2022, from the results of these two methods, a
map of the criticality level of the water catchment area of ??the northern
Gunungpati sub-district will be obtained, which will then be compared between
the two methods by verifying the area and using analysis. Receiver Operating
Characteristic (ROC). Land uses that have a fast infiltration rate are forests
and plantations of around 35%, infiltration rates that have a moderate
infiltration rate of around 19%, steep-very steep slopes of around 24%,
constituent lithologies that have high permeability potential are alluvium
deposits with sand - gravel 2% , sandstone units with conglomerate inserts 16%
and the depth of the groundwater table which has the highest water absorbing
capacity is 10m - 20m depth, around 55%. So from these results, we obtained
data on the area of ??the critical level of the water catchment zone using the
2 methods, namely the AHP method. The results showed that the area of ??the
area for each classification of the level of criticality of water catchment was
in good condition, 2.53 km2 with a percentage of 9%, the natural
normal is 2.78 km2 with a percentage of 10%, critical start at 6.43
km2 with a percentage of 23%, a rather critical 10.48 km2
with a percentage of 38%, critical 5.36 km2 with a percentage of
19%, very critical 0.35 km2 with a percentage of 1%. The method of
Minister of Environment and Forestry Regulation No. 10 of 2022 shows that the
area conditions for each classification of water catchment criticality level
are 1.85 km in good condition.2 with a percentage of 7%, the natural
normal is 6.45 km2 with a percentage of 23%, starting to be critical
at 10.14 km2 with a percentage of 36%, a rather critical 7.14 km2
with a percentage of 26%, critical 2.14 km2 with a percentage of 8%,
very critical 0.35 km2 with a percentage of 1%. Comparative results
of the two methods Analytical Hierarchy Process and the method of Minister of
Environment and Forestry Regulation No. 2022 using validation Area Under Curve
(AUC) with AHP method values 0.725 falls into the category Fair Classification
and the method of Minister of Environment and Forestry Regulation No. 2022 with
a performance value of 0.624 is included in the category poor classification. So
from the validation results of Area Under Curve (AUC) it can be concluded that
the AHP method is better than the method of Minister of Environment and
Forestry Regulation No. 10 of 2022.
Kata Kunci : Urbanization, water infiltration, Analytical Hierarchy Process, environment and forestry Ministerial Decree no. 10 of 2022, Receiver Operating Characteristic (ROC)