Mrica Reservoir located in Banjarnegara Regency is amultipurpose reservoir. Based on the report of PT Indonesia Power UnitPembangkitan (UP) Mrica in 2016, the sediment of Mrica Reservoir hasentered the critical phase as it reached 114.25 million m3 and the value ofland-cover index of Mrica reservoir was 80% of the total watershed areawith the average sedimentation rate reaching 4.09 million m3 per year. Itis estimated that the reservoir will be full of sediment by 2021. The maincause of the high rate of sedimentation in Mrica reservoir is the changes inland use and agricultural-plantation activities in the upper river areas andalong the river flow of Serayu River, Merawu River, and Lumajang River. This study aimed to determine the appropriate type of conservation forMrica Reservoir. The method used was the Analytical Hierarchy Process(AHP), in which the determination of conservation efforts was based onsecondary data and observation. According to the current condition ofMrica Reservoir, the planned conservation efforts include two types, namely non-structural conservation and structural conservation. If theconservation begins in 2019, the total sediment in 2021 will decrease to74% and it is predicted that the sediment will be exhausted by 2056.
INTISARIKondisi fisik kawasan karst yang didominhasi oleh bentuklahan hasil proses pelarutan batuan menyebabkan berkembanganya sistem pelorongan, drainase bawah tanah dan sistem gua. Hal tersebut menyebabkan kelangkaan air di bagian permukaan sehingga kawasan karst lebih dikenal sebagai kawasan yang rawan terhadap bencana kekeringan. Penelitian ini bertujuan untuk (1) mengetahui peranan organisasi masyarakat lokal dalam pengelolaan sumberdaya air yang terbatas pada musim kemarau di Dusun Turunan, Kecamatan Panggang, kabupaten Gunungkidul, dan (2) mengidentifikasi strategi adaptasi masyarakat dalam menghadapi bencana kekeringan di kawasan karst. Hasil penelitian menunjukkan bahwa organisasi masyarakat berperan sangat besar dalam pengelolaan sumberdaya air pada musim kemarau. Organisasi ini berperan dalam pembagian jatah air, pengoperasian pompa, perawatan dan pengelolaan instalasi penyedia air, dan pengawasan terhadap pemanfaatan air. Strategi adaptasi terhadap bencana kekeringan yang dilakukan berupa larangan memandikan ternak, larangan mencuci motor, serta pembagian penyaluran air untuk masing-masing kelompok rukun tetangga.Kata Kunci: Organisasi Masyarakat, Strategi Adaptasi, Kekeringan, Karst I. PENDAHULUANProses pelarutan batuan yang terjadi akibat adanya interaksi air hujan, karbondioksida dan batuan karbonat telah menyebabkan terbentuknya kawasan karst (Ford dan William, 1992). Proses tersebut menyebabkan terbentuknya sistem pelorongan, drainase bawah tanah, sistem gua serta celahcelah pelarutan yang menyebabkan air di permukaan dalam waktu singkat masuk ke dalam sistem bawah tanah (White, 1988). Hal ini menyebabkan kondisi kering di permukaan, sehingga sumber air di permukaan jarang sekali ditemukan (Cahyadi, 2010). Hal inilah yang menyebabkan kawasan karst terkenal sebagai kawasan yang rawan terhadap bencana kekeringan (Suryanti dkk. 2010).Jarangnya sumber air permukaan di kawasan karst menyebabkan mataair dan telaga yang merupakan sumber air dipermukaan menjadi sangat penting (Worosuprojo dkk, 1997;Santosa, 2007).Jumlah air yang terbatas dibandingkan jumlah kebutuhan yang banyak tentunya akan mendorong terbentuknya pola adaptasi masyarakat (Awang, 2005). Hal ini karena secara naluriah manusia akan berusaha bertahan hidup dalam kondisi keterbatasan (Twigg, 2004). Namun demikian, dalam bertahan hidup tersebut, manusia dikontrol oleh norma-norma yang berlaku sehingga kemudian memunculkan pola adaptasi yang unik dan khas di dalam kelompok masyarakat (Sudarmaji dkk, 2012).
Farmers in Indonesia widely use organophosphate pesticides (OPPs) to increase crop production, despite their risk to human health and the environment. Objective of this study is to estimate the loading rate and risk level of OPPs based on OPPs characteristics, farmers’ knowledge, and the behavior of OPPs application in agriculture area in Yogyakarta Special Region in Indonesia. Data collected through interview and questionnaire distribution revealed three types of OPPs used in study area; profenofos, chlorpyrifos and diazinon. Data on application dose and crop area were used to estimate loading rate. Risk scores can be calculated by multiplying loading rate with toxicity data of each type of OPPs used. Box-Cox transformation was then used to normalized rightly skewed risk score data to get 4 (four) levels of risk classification range; low, medium, high and very high. It was found that there were areas classified as very high risk in wet season, while it is not the case in dry season. However, in total loading per year, areas with high and very high risk level were found for more than >50% in study area.
Fomasi litologi akuifer batugamping mempunyai karakteristik media aliran berupa celah, rekahan, dan lorong pelarutan, sehingga memiliki potensi mengalirkan airtanah dengan kecepatan tinggi. Produktivitas yang tinggi ini mengakibatkan sumber pencemar di permukaan dapat dengan cepat meresap ke sistem akuifer dan bercampur dengan airtanah; kondisi inilah yang memicu kerentanan tinggi. Salah satu langkah pengelolaan airtanah pesisir adalah penentuan zona kerentanan airtanah terhadap pencemaran. Dengan demikian, tujuan penelitian ini adalah untuk mengetahui tingkat kerentanan airtanah pesisir terhadap pencemaran di formasi batugamping menggunakan metode COP dengan pendekatan intrinsik dan metode EPIK dengan pendekatan perkembangan karst. Hasil penilaian menggunakan kedua metode tersebut menunjukkan tingkat kerentanan rendah hingga sangat tinggi. Pemetaan metode COP menghasilkan dua kelas kerentanan: rendah (95% dari luas wilayah) dan sedang (4%), sedangkan metode EPIK menghasilkan zona indeks kerentanan yang lebih panjang dengan empat kelas kerentanan, yaitu rendah (1,23%), sedang (17,82%), tinggi (17,82%), dan sangat tinggi (21,65%). Dibandingkan dengan COP, EPIK menghasilkan kelas kerentanan yang lebih tinggi karena pengaruh koefisien pembobot pada formula penghitungannya. Hasil penilaian kerentanan divalidasi dengan indikator limbah domestik berupa senyawa nitrat (NO3). Uji laboratorium menunjukkan kandungan nitrat (NO3) airtanah yang bervariasi dari 0,12 mg/l (terendah) hingga 9,80 mg/l (tertinggi). Variasi ini masih berada di bawah baku mutu air minum tetapi di atas baku mutu air limbah domestik atau melebihi kadar nitrat di alam. Berdasarkan hasil validasi, zona kerentanan berkorelasi dengan kandungan nitrat (NO3). Pada zona kerentanan yang tinggi, ditemukan kadar nitrat yang tinggi pula.ABSTRACTA limestone aquifer is lithologically characterized by three flow media: fissures, fractures, and dissolution channels, thus creating the potential to drain groundwater at a high rate. This high productivity, however, means that the groundwater is highly vulnerable to pollution. If a pollutant source is present on the surface, it can quickly seep into and mix with the subsurface system. Among the widely proposed management strategies is groundwater vulnerability zoning. This study was intended to determine the degrees of coastal groundwater vulnerability to pollution in a limestone formation with two methods: COP intrinsic vulnerability) and EPIK (karst development-based vulnerability). The assessment results showed that the vulnerability produced with both methods varied from low to very high. In the mapping, COP produced two levels: low (95% of the total area) and medium (4%), while EPIK generated a longer vulnerability index zone with four levels: low (1.23%), medium (17.82%), high (17.82%), and very high (21.65%). Compared to COP, EPIK results in a higher vulnerability class due to the weighting values in its vulnerability assessment. The results were validated with a domestic waste indicator: the presence of nitrate (NO3). Laboratory tests showed NO3 concentrations in the range 0.12 of 9.80 mg/l. These figures are still below the quality standard for drinking water but above that of domestic wastes or exceeding the maximum NO3 content found in nature. The validation revealed that the vulnerability zone is correlated with NO3 levels: the higher the vulnerability class of the zone, the higher the nitrate content.
This research was conducted in Maputo City, the capital city of Mozambique, as one of developing cities which in the needs to support its urban physical features. It aimed to (1) identify environmental problems in the coastal zone of Maputo, (2) identify the existing Integrated Coastal Zone Management (ICZM) in the coastal zone of Maputo, and (3) formulate a plan of ICZM in Maputo. It was conducted by field observation on several points following the literature study. Points were chosen according to difference in physical coastal appearance such as the presence of berms, frontal dunes, artificial barriers, and coastal structures. Results showed that the coastal area in Maputo City experiences three environmental problems i.e. coastal abrasion, improper land use to its conservation concept, and poor waste management. There is already structural mitigation in the area which is in the form of jetties and seawalls. However, it only attempts to solve problems technically. ICZM which bases on coastal zone’s potential risk, then, becomes handy in solving the problems related to people awareness in improving the effectiveness of waste management as well as the properness of land utilization in the study area.
The impact of climate change on various aspects of human life is expected to increase. Cays, very small islands, are predicted to experience the most severe impact. Changes in temperature and precipitation, as the two climatic elements that control the intensity of erosion and mass wasting, disturb the continuity of existing geomorphological processes in shaping various features of cays. Therefore, aside from assessing the possible impact, deeper understanding on geomorphological characteristics becomes necessary to identify the future environmental response of cays particularly to the effects of climate change on resources and geomorphological hazards. This research aimed to analyze the geomorphological condition of Pramuka Cay, Kepulauan Seribu Regency, Jakarta, Indonesia. The analysis results show that Pramuka Cay is an island formed of bioclastic deposits that occupy the upper part of patch reef in the form of pinnacle. Its geomorphology consists of cay, reef flat, reef edge, reef slope, and regolith mound in front of reef slope. In terms of climate change, these geomorphological characteristics make Pramuka Cay become vulnerable to sea level rise and coastal erosion.
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