To recognize the groundwater flow system in the Bandung Basin, two main methods of regional groundwater flow delineation were employed: hydraulic heads and tracers. Two different environmental tracers, i.e. subsurface temperature and stable isotope were applied. The measured temperatures and stable isotope compositions from 19 observation wells lead to the recognition of three types of flow systems within the Bandung Basin i.e., shallow, intermediate and deep groundwater flow system. The recharge area is located in the hills and upland which form the periphery of the plain. The summit area of the southern mountainous complex might have represented the highest recharge area. No indication was found for water being recharged at higher elevation in the northern part of the basin which means the recharged water in the Mount Tangkuban Parahu area did not reach the Bandung Plain. This study clearly demonstrates the usefulness of these environmental tracers and hydraulic head measurement in identification of the groundwater flow system of a certain area.

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Pulled by gravity, fresh groundwater will come in contact with seawater at the downstream end of its flow system. Most previous work has discussed the shape of the seawater/freshwater interface on the basis of Ghyben-Herzberg's law. The groundwater, however, will come out to the surface as coastal springs or predicted by the law, the freshwater also can flow out from the bottom of the sea. The event of freshwater flows from the bottom of the sea or submarine is named submarine groundwater discharge (SGD). The analysis shows that the freshwater flows discharges along the interface, even as a submarine springs. Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. The understanding of SGD will facilitate the development of water resources and the evaluation of environments. This paper reviews the scientific significance of SGD evidence in Indonesia. It is concluded that while the SGD process is essentially ubiquitous in Indonesia coastal areas, the assessment of its characteristic should be made base on geology and hydrogeological condition. SGD estimation has been made in 6 locations, Kata Kunci : Keluaran airtanah di lepas pantai, mata air, air tawar, pantai, Indonesia Lubis, Rachmat Fajar, et.al / Riset Geologi dan Pertambangan

Surface wáter and shallow groundwater, along streams segments across Cianjur city, have ABSTRAK Air permukaan dan airtanah dangkal pada sumur-sumur gali di sepanjang ruas-ruas sungai yang melintasi kota Cianjur ke arah hilir telah dianalisis untuk mengetahui tingkat pencemarannya. Air Permukaan dan Airtanah dangkal di Hilir kota Cianjur telah mengalami pencemaran pada tingkat yang berbeda. Pada air permukaan pencemaran ditandai dengan kandungan BOD tinggi sehingga air tidak dapat langsung dimanfaatkan sebagai bahan baku air minum, tetapi masih dapat dimanfaatkan sebagai air irigasi dan perikanan. Proses pemurnian kembali air di daerah studi tampaknya tidak akan terjadi karena jumlah rata-rata limbah yang masuk secara acak lebih besar daripada daya pulih aliran di daerah tersebut. Gejala pencemaran Nitrogen telah tampak pada air tanah dangkal, tetapi air masih dapat digunakan sebagai sumber air minum. Untuk mengantisipasi memburuknya keadaan di masa mendatang, perlu mulai difikirkan untuk mengelola sumberdaya air daerah ini dengan pendekatan hidrologi urban.Kata kunci : pencemaran, air permukaan, daya pulih, airtanah dangkal, perkotaan, nitrogen. PENDAHULUANKota-kota di Indonesia, khususnya di Jawa barat, kini sedang mengalami pertumbuhan yang pesat. Di beberapa kota besar, kesulitan air bersih sudah umum dirasakan oleh sebagian besar penduduknya, seperti misalnya Jakarta dan Bandung, yang secara iklim serta kerangka