KAJIAN POTENSI AIRTANAH DI LERENG SELATAN GUNUNGAPI MERAPI UNTUK MENCUKUPI KEBUTUHAN AIR DOMESTIK PADA HUNIAN SEMENTARA

Sadewa Purba Sejati, Dr. Tjahyo Nugroho Adji, M. Sc., Tech.

2013 | Tesis | S2 Geografi

Erupsi Gunungapi Merapi tahun 2010 menyebabkan kerusakan pemukiman di lereng bagian selatan. Pemerintah kemudian menyediakan hunian sementara (Huntara) bagi para korban erupsi. Berdasarkan kebijakan pemerintah dan instansi terkait, Huntara kemudian akan dijadikan hunian tetap (Huntap) sebagai upaya relokasi korban erupsi. Berkaitan dengan hal itu, penelitian ini dilatar belakangi oleh perlunya informasi mengenai potensi airtanah sebagai sumber pemenuhan kebutuhan domestik Huntara dan rumusan rencana strategi pengelolaan potensi airtanah. Tujuan penelitian ini adalah (1) mengetahui potensi airtanah daerah penelitian, (2) mengetahui potensi airtanah untuk mencukupi kebutuhan domestik Huntara, dan (3) merumuskan rencana dan strategi pengelolaan potensi airtanah. Data primer yang digunakan meliputi kedalaman muka airtanah, elevasi, kualitas airtanah, dan jumlah kebutuhan airtanah pada Huntara. Data sekunder meliputi data bor, data kontur elevasi, dan data pendukung lainnya. Sampel data primer ditentukan secara acak sistematik, acak proporsional, dan purposif. Tujuan (1) dicapai dengan menentukan kuantitas dan kualitas airtanah. Kuantitas airtanah diketahui dengan metode debit dinamis, kualitas airtanah diketahui dengan membandingkan nilai hasil uji laboratorium sampel airtanah terhadap nilai pada peraturan mengenai kualitas air. Tujuan (2) dicapai dengan membandingkan kuantitas airtanah yang tersedia dengan jumlah kebutuhan air untuk domestik pada Huntara. Tujuan (3) dicapai dengan analisis SWOT, dimana rencana dan strategi pengelolaan merupakan konsep subyektif yang dihasilkan dari interaksi antara faktor internal dan eksternal potensi airtanah daerah penelitian. Hasil penelitian diuraikan secara deksriptif kuantitatif, deskriptif kualitatif, dan komparatif. Hasil penelitian meliputi (1) potensi airtanah daerah penelitian memiliki nilai prediksi debit dinamis sebesar 17.980.174 l/hari atau 17.980,2 m3/hari, dan 71% kualitas airtanah dalam kondisi baik. (2) Potensi airtanah dapat mencukupi kebutuhan domestik Huntara karena jumlah kebutuhan domestik Huntara (1.032.634,5 l/hari atau 1032,6 m3/hari) lebih kecil daripada prediksi debit dinamis airtanah, dan hampir seluruh airtanah di lokasi Huntara memiliki kualitas baik; (3) Rumusan rencana pengelolaan potensi airtanah meliputi (a) pemerataan fungsi potensi airtanah (b) pengendalian limpasan air hujan dan perlindungan kualitas airtanah, (c) optimalisasi potensi airtanah pada daerah yang memiliki keterbatasan, dan (d) antisipasi penurunan potensi airtanah.

Merapi Volcano eruption in 2010 has caused damage to settlements on the southern slope. The Government was then provided temporary housing (Huntara) for the victims of the eruption. Based on the policy of the Government and related institutions, Huntara was then intended to become a permanent housing (Huntap) in an effort to relocate victims of the eruption. Relevant to this, the current study is motivated by the need for information about groundwater potential as a source of fulfillment of domestic needs for the temporary housing and about the strategic plan formulation of groundwater potential management. The objectives of the study are to: (1) determine the groundwater potential in the researched area, (2) determine the groundwater potentials to fulfill the domestic needs of temporary housing, (3) formulate the plan and strategy of groundwater potential management. The primary data employed include the depth of groundwater surface, elevation, groundwater quality, and the amount of water needed by the temporary housing. The secondary data include those of drilling, elevation contours, and other supporting data. The primary data samples were determined on systematic random, proportional random, and purposive bases. Objective 1 was achieved by determining the quantity and quality of groundwater. Groundwater quantity was determined by the method of dynamic discharge, groundwater quality was determined by comparing the results of laboratory testing of groundwater samples to the value promulgated in water quality regulation. Objective 2 was achieved by comparing the quantity of the available groundwater to the amount of water for domestic needs in temporary housing. Objective 3 was achieved by SWOT analysis, where plans and management strategies are subjective concepts that results from the interaction between internal and external factors of groundwater potential in the researched areas. The results were described on quantitative descriptive, qualitative descriptive, and comparative bases. They indicated: (1) that groundwater potential of the researched areas have a predictive value for dynamic discharge of 17.980.174 l/day or 17980,2 m3/day, and that 71% of groundwater is in good quality; (2) that the groundwater potential can meet domestic needs of temporary housing due to the smaller needs of the housing (1.032.634,5 l/day or 1032,6 m3/day) than the predicted dynamic discharge of groundwater and that almost all groundwater at the temporary housing site have a good quality; (3) That the formulation of groundwater potential management plan includes: (a) the distribution of groundwater potential function (b) control rainwater runoff and groundwater quality protection, (c) optimizing the groundwater potential in the area with limitations, and (d) anticipation of decreasing groundwater potential.

Kata Kunci : debit dinamis airtanah, kualitas airtanah, kebutuhan airtanah domestik pada Huntara, pengelolaan potensi airtanah