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Muara Karang Power Plant (MKPP) is one of the main power plants on Java Island in Indonesia. Presently, the Jakarta provincial government has issued a reclamation project on Island G in the marine waters around MKPP. This reclamation effort is predicted to lead to a rise in the seawater temperature around the intake, which MKPP will address with the addition of intake channel of 250 - 957 m. Therefore, this study aimed to determine the effect of intake channel extension on the water temperature at the intake point using numerical modeling comprising hydrodynamics and dispersion advection modules. A total of 10 scenarios were modeled by varying intake channel length and season. The result showed that adding intake channel was less effective because the average water temperature was less than 0.24oC with an effectiveness below 0.78%. Based on the validation of the modeling results on the measurement data, the NRMSD values in west and east seasons were 9.13% and 12.63%, respectively. Under existing conditions, the average and maximum seawater temperatures were 31.40oC and 32.08oC. Meanwhile, by extending intake channel, the average and maximum water temperatures were 31.16oC and 31.60oC. These results showed that by extending intake channel, the temperature at the intake point was generally lower than the existing conditions. Intake channel length was more effective in reducing the temperature at the intake point during west monsoon than east monsoon. Vertically, the temperature at the bottom was relatively colder than near the surface. In west monsoon, the average temperature difference between the bottom and the surface ranged from 0.16-0.21oC, while in east, it was between 0.23 and 0.50oC. In conclusion, the addition of subsequent structures to increase effectiveness was necessary, specifically to hold hot water in east monsoon.

NCICD is one of the national strategic programs to deal with coastal problems in Jakarta. One alternative structure to be built is WLP or known as coastal resort. As an initial step to make it happen, BAPPENAS plans to build a WLP pilot plan around the S. Cisadane estuary. One of the main considerations for designing the WLP layout is the process and pattern of sedimentation around the Cisadane estuary. Therefore, computational modeling of sediment transport around the Cisadane estuary was carried out for a period of 1 year (August 2020-July 2021). This modeling uses MIKE-21 module MIKE21/3 Integrated Models software which combines hydrodynamics and cohesive sediment transport models. Based on the results of this modeling, it is known that there are differences in sediment transport patterns in the west and east monsoons. During 1 year, changes in the thickness of the bottom sediment around the estuary of S. Cisadane ranged from -0.4 to 0.7 m with a mean of 0.086 m. Coastal reservoir design must take into the very dynamic sedimentation process around the Cisadane estuary. Pengembangan Terpadu Pesisir Ibukota Negara (PTPIN) merupakan salah satu program strategis nasional untuk menangani permasalahan pesisir di Jakarta. Salah satu alternatif struktur yang akan dibangun adalah WLP atau dikenal sebagai coastal reservoir. Sebagai langkah awal mewujudkannya BAPPENAS merencanakan membangun pilot plan WLP di sekitar muara S. Cisadane. Salah satu pertimbangan utama untuk mendesain layout WLP adalah proses dan pola sedimentasi di sekitar muara Cisadane. Oleh karena itu dilakukan pemodelan komputasi transpor sedimen di sekitar muara Cisadane selama kurun waktu 1 tahun (Agustus 2020-Juli 2021). Pemodelan ini menggunakan software MIKE-21 module MIKE21/3 Integrated Models yang menggabungkan model hidrodinamika dan transpor sedimen kohesif. Berdasarkan hasil pemodelan ini diketahui bahwa terdapat perbedaan pola transpor sedimen di musim barat dan musim timur. Selama 1 tahun, perubahan ketebalan sedimen dasar di sekitar muara S. Cisadane berkisar -0,4-0,7 m dengan rerata 0,086 m. Pola sedimentasi yang sangat dinamis harus mendapatkan perhatian khusus dalam merancang waduk lepas pantai.

Jelitik River is the main river and economic artery of Sungailiat District, Bangka Regency. Currently around the Jelitik River there is a Jelitik Fishing Port and is developed as an industrial area. In addition to the problems of sedimentation problems with the development of industrial estates and the presence of sand mining rich in tin ore on land and on the high seas it is feared that it will reduce the quality of the environment, especially the surrounding sea water. Therefore, this study is needed in order to find out the quality of waters in this estuary which can be used as a basis or baseline for the initial environment of this region if later this area will be developed as a port or industrial area. The method used in this study is field observation, water sampling, and laboratory analysis. Therefore, as an initial step, it is necessary to identify the quality of the waters in this estuary which can be used as the basis or initial environmental baseline of this area if later this area will be developed as a port or industrial area. Based on observations in the field of laboratory analysis of water samples, generally the quality of seawater around the estuary of Jelitik River still meets seawater quality standards both for port activities, marine tourism and for biota. Some parameters that exceed the quality standard include total suspended solid (TSS) which reaches 250 mg/l, total dissolved solids (TDS) which reaches 24,700 mg/l and nitrate content which reaches 0.38 mg/l. BOD value is 4.7 mg / l and COD is 46.4 mg / l, these parameters are still below the existing sea water quality standard.

ABSTRAK Saat ini untuk memenuhi kebutuhan energi listrik pemerintah mencanangkan program pembangunan pembangkit listrik 10.000 MW. Salah satu implementasinya dengan membangun Pembangkit Listrik Tenaga Uap (PLTU) berbahan bakar batubara seperti PLTU Sampit di Kabupaten Kotawaringin Timur, Propinsi Kalimantan Tengah. Permasalahan utama kegiatan PLTU adalah suhu air buangan yang jauh lebih tinggi dari suhu perairan di sekitarnya. Kenaikan suhu iniselain akan mengurangi efisiensi system pendinginan juga dapat membahayakan kehidupan aquatik. Untuk meminimalkan dampak perlu dilakukan pemodelan adveksi/dispersi panas sebelum dilakukan pembangunan PLTU. Dengan pemodelan ini akan diketahui sebaran panas buangan PLTU sehingga sejak awal dapat dilakukan upaya-upaya untuk mengurangi dampak negatif yang muncul. Selain itu model ini dapat dipakai sebagai bahan pertimbangan dalam penentuan lokasi intake dan outfall sistem air pendingin. Studi ini dilakukan dalam beberapa skenario dengan menggunakan perangkat lunak MIKE-21. Berdasarkan hasil pemodelan diketahui bahwapola arus di perairan sekitar PLTU Sampit lebih dipengaruhi pasang surut dan debit sungai dari hulu. Pada musim timur, suhu air pada lokasi intake cukup terpengaruh oleh suhu air bahang pada outfall khususnya ketika air laut pasang. Perubahan temperaturair pada intake berkisar antara 30,1 – 32 oC. Kenaikan tertinggi terjadi ketika air menuju pasang naik maksimum. Pada musim angin barat, suhu air pada lokasi intake hanya sedikit terpengaruh oleh suhu air bahang pada outfall, perubahan temperatur air pada intake hanya berkisar antara 29,99 – 30,1 oC. Kenaikan tertinggi terjadi ketika air menuju pasang naik maksimum. Resirkulasi air pendingin dengan intensitas cukup besar (+ 2oC) diprediksi terjadi saat air pasang. Hal ini dapat menjadi lebih parah bila debit sungai dari hulu berkurang yaitu ketika musim kemarau. Kata kunci: dispersi panas, PLTU, air bahang, intake, outfall ABSTRACT Now to comply the electricity needs, government announced the construction of 10,000 MW power plant. One of its implementation by building Steam Power Plant (PLTU) with coal-fired power such as Sampit in the District of Eastern Kotawaringin, Province of Center of Kalimantan. The main problem of power plant activities is the waste water temperatures much higher than the temperature of the surrounding waters. The rise of temperature will not only reduce the efficiency of the cooling system but also be harmful to aquatic life. To minimize the impact needs to be done advection/dispersion modeling of heat water prior to the construction of the power plant. With this modeling will be known distribution of heat waste from power plant in 2-dimensional, so that can be done since the beginning of efforts to reduce the negative impacts that arise. In addition, this model can be used as a consideration in the determination of the location of the intake and outfall system cooling water. This study was conducted in several scenarios using software MIKE-21. Based on modeling results is known that the current pattern in the waters around the Sampit power plant is more affected by tidal and river flow from upstream. In east monsoon, the water temperature at the intake is quite affected by the heat water temperature at the outfall especially when high tides. Water temperatur changes in intake ranged from 30.1 to 32 oC. The highest increase occurred when the water toward the maximum high tide. In the west monsoon, the water temperature at intake only slightly affected by the heat water temperature on the outfall. Eater temperatur changes on the intake only ranged from 29.99 to 30.1°C. The highest increase occurred when the water toward the maximum high tide. Recirculation cooling water with considerable intensity (+ 2°C) could occur during high tide. It can be more severe if the river flow from upstream is reduced like as at the dry season. Keywords: thermal dispersion, steam powerplant, heat waste water, intake, outfall Citation: Wibowo, M., Hendriyono, W., Nugroho, S., Al Hakim, B., Velly Asvaliantina. V. (2017). Kajian Dispersi Panas Dampak Rencana Pembangunan PLTU Sampit-Kotawaringin Timur Propinsi Kalimantan Tengah. Jurnal Ilmu Lingkungan, 16(1), 86-97, doi:10.14710/jil.16.1.86-97

Pada dasarnya semua kegiatan pembangunan khususnya di kawasan pesisir akan menimbulkan perubahan terhadap lingkungan sekitarnya baik yang positif maupun negatif. Tidak terkecuali rencana pembangunan kawasan marina di pantai Tanjungpendam Kabupaten Belitung pasti akan menimbulkan dampak terhadap kualitas lingkungan perairan di sekitarnya. Metode yang dipakai dalam kajian ini adalah kompilasi dan analisis data sekunder, melakukan tinjauan dan observasi lapangan, analisis data sekunder yang ada, analisis desain kawasan marina yang akan dibangun, memperkirakan dampak lingkungan serta menyusun usulan untuk pengelolaan dan pemantauan dampak yang mungkin terjadi. Pada tahap konstruksi dan operasional kawasan marina, dampak terhadap lingkungan yang mungkin terjadi adalah menurunnya kualitas perairan laut, kualitas udara, terjadinya perubahan pola arus, abrasi dan sedimentasi serta terganggunya kehidupan biota yang ada di sekitar dermaga. Dampak-dampak lingkungan yang ditimbulkan umumnya dikategorikan sebagai dampak negatif dan bersifat terus menerus. Untuk meminimalisir dampak negatif yang mungkin timbul diperlukan adanya upaya pengelolaan lingkungan dan upaya pemantauan lingkungan.

Rona lingkungan awal kualitas air sungai dan sedimen dasar sangat diperlukan sebelum dilakukan pengerukan sebagai bahan untuk memperkirakan dampak lingkungan yang muncul akibat kegiatan pengerukan. Pengambilan sampel air dilakukan dengan mengikuti Standard Method dari APHA-AWWA (1995) dan dianalisis di laboratorium dengan berpedoman pada Peraturan Pemerintah No. 82 Tahun 2001 Tentang Pengelolaan Kualitas Air dan Pengendalian Pencemaran Air. Berdasarkan hasil analisis dan kajian ini diketahui bahwa kualitas air sungai di Kutai Lama masih tergolong baik (berdasarkan baku mutu air Kelas I PeraturanPemerintah No. 82 Tahun 2001). Beberapa parameter yang melebihi baku mutu air Kelas I PP No. 82 Tahun 2001 adalah BOD, COD, DO, Besi (Fe), deterjen sebagai MBAS. Khusus untuk kandungan logam berat semuanya masih memenuhi baku mutu yang telah ditetapkan. Kualitas sedimen dasar: konsentrasi logam mangan (Mn) sangat tinggi jika dibandingkan dengan konsentrasi logam-logam lainnya. Konsentrasi logam berat yang ditemukan dalam jumlah besar berikutnya adalah besi (Fe), seng (Zn), tembaga (Cu) dan yang terkecil adalah timbal (Pb).Berdasarkan standar baku mutu sedimen yang dibuat oleh United State Environmental Protection Agency (USEPA) dan Kementerian Lingkungan Kanada, semua konsentrasi logam-logam berat di daerah kajian termasuk dalam kategori tercemar berat.