Hidrogeologi untuk pengembangan wilayah :: Studi kasus wilayah Bima Propinsi Nusa Tenggara Barat

SYAHWAN, Muhammad, Dr.Ir. Heru Hendrayana

2007 | Tesis | S2 Teknik Geologi

Airtanah saat ini telah memainkan peran penting di dalam penyedian pasokan kebutuhan air berbagai keperluan, seperti : pemukiman, pertanian, perikanan, industri, perdagangan dan sebagainya. Penelitian hidrogeologi mengenai arahan pengembangan wilayah di daerah Bima dan sekitarnya Propinsi Nusa Tenggara Barat bertujuan untuk mengetahui potensi airtanah, baik kualitas maupun kuantitasnya di daerah penelitian, mengetahui kebutuhan airtanah untuk keperluan rumah tangga, pertanian dan industri dan arahan pengembangan wilayah dimasa akan datang meliputi kawasan pemukiman, kawasan industri dan kawasan pertanian. Pengumpulan data sekunder meliputi data hidrogeologi, data geologi, data hidrologi, data tata guna lahan dan data jumlah penduduk. Melakukan penelitian lapangan, meliputi: penelitian geologi dan hidrogeologi. Dari hasil penelitian diketahui kondisi geomorfologi menjadi empat satuan geomorfologi, meliputi: satuan dataran fluvial, satuan geomorfologi dataran endapan pantai, satuan geomorfologi perbukitan – tersayat kuat berlereng curam denudasional dan satuan geomorfologi perbukitan – tersayat kuat berlereng curam vulkanik, kondisi geologi menjadi 4 satuan batuan, urutan stratigrafi pada daerah penelitian dari yang tua – muda meliputi: Satuan andesit, satuan tuf, satuan batugamping dan satuan aluvium. Daerah penelitian memiliki 3 sistem akuifer, yaitu: akuifer dengan aliran melalui ruang antar butir, terbagi menjadi 2, yaitu: akuifer produktivitas tinggi dan akuifer produktivitas sedang, akuifer dengan aliran melalui rekahan dan celah dan akuifer dengan produktivitas kecil dan langka, terbagi menjadi 2, yaitu: akuifer produktivitas kecil dan akuifer produktivitas langkah. Jumlah imbuhan airtanah pada daerah penelitian adalah 179.692.200 m3/tahun, dengan luas wilayah penelitian 69.109.200 m2, total cadangan statis di daerah penelitian adalah 115.761,60 m3 dengan luas daerah 21.708.000 m2, cadangan dinamis di daerah penelitian adalah 188.501,75m3/hari. Untuk arahan pengembangan wilayah kawasan permukiman, meliputi: daerah Penatoi, Penaraga, Raba Ngodu, Raba Dompu, Panda dan Belo, untuk kawasan pertanian, meliputi: daerah Belo, Raba Dompu, Raba Ngodu, untuk kawasan industri, meliputi: daerah Tanjung, Dara, Sadia dan Kumbe, telah memenuhi standar kualiatas airtanah.

Nowadays, groundwater has played important role in providing the supply of the water need used in the kinds of necessity, such as settlement, agriculture, fishery, industry, trade and etc. In this case, hidrogeology research relates to the direction of the region development in Bima distic and surrounding. The district of West Nusa Tenggara aims to know the potential of groundwater observerd from the quality and the quantity in the research district. It’s conducted to know the need of groundwater for domestic, agriculture and industry. And also, the instruction of region developmebt is in the future, including settlement, industry and agriculture area The collection of the data secondary includes hydrogeology data, geology data, hidrology data, land use and the data of population. In doing the research, it’s concerued on geology and hidrogeology research. From the result of the research, it’s know from the geomorfology condition become 4 geomorfology units, including fluvial plain unit, coastal plain unit, hillysteeply dissected/steep topography denudation unit and hilly-steeply dissected/steep topography volcanic unit. The condition of geology is divided into 4 rocks units, the sequence of stratigraphy in the past until present of the research region, suc has andesit, tuff, limestone, medium gravel – coarse gravelunits. Whereas, this research district has 3 aquifer systems, that is aquifer with the flow of groundwater through porosity. It is divided into 2 part, that is the aquifer of high productivity and the aquifer of medium productivity, aquifer with the flow through the fracture and the gap, and the aquifer with low and rare productivity. It’s also divided into two groups, such as aquifer of the low productivity and aquifer of the rare productivity. The total of given groundwater in the research area is 179.692.200 m3/year, with the total of the research district as 69.109.200 m2. And the total of static groundwater storage in the research area is 115.761,60 m3 with the total of district 21.708.000 m2, and dynamic groundwater storage in the research district is 88.501,75 m3/day. To direction the development region of the settelement area, it includes Penatoi district, Penaraga, Raba Ngodu Raba, Dompu, Panda and Belo. To agriculture area, it is: Belo district, Raba Dompu and Raba Ngodu. And to industrial area, it includes: Rontu Sadia and Kumbe, it has fulfilled the standar of the groundwater quality.

Kata Kunci : Hidrogeologi,Cadangan Air Tanah,Pengembangan Wilayah, Region development, groundwater storage, aquifer systems, groundwater usage