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Mangrove adalah tipe vegetasi yang terdapat di daerah pantai tropis. Hutan mangrove sebagai salah satu sumberdaya alam yang potensial yang dimanfaatkan oleh masyarakat. Pemanfaatan hutan mangrove yang berlebihan dan tidak diimbangi dengan rehabilisasi akan menyebabkan penurunan luasan mangrove yang menyebabkan berkurangnya fungsi mangrove dalam ekosistem. Salah satu faktor yang mempengaruhi pertumbuhan mangrove adalah tanah atau substrat. Pada umumnya kawasan hutan mangrove terdapat di seluruh pantai Indonesia dan tumbuh pada lokasi-lokasi yang masih dipengaruhi oleh aktivitas pasang. Kerusakan hutan mangrove terluas di Bali terjadi di kawasan Tahura Ngurah Rai yaitu seluas 253,4 hektar dari luas total 1.373,5 hektar. Tujuan dari penelitian ini adalah mengetahui struktur komunitas mangrove berdasarkan karakteristik subtrat di Taman Hutan Raya Ngurah Rai, Bali. Pengumpulan data menggunakan metode line transek dan dianalisis secara kuantitatif dengan menggunakan analisis INP. Dari lima stasiun penelitian ditemukan Sembilan spesies mangrove diantaranya: Sonneratia alba, Rhizophora mucronata, Rhizophora apiculata, Bruguiera gymnorhiza, Bruguiera sexangula, Xylocarpus granatum, Avicennia lanata, Avicennia officinalis dan Aegiceras floridium. Komponen substrat di TAHURA didominanasi oleh pasir diikuti oleh liat dan lumpur. Spesies Sonneratia alba dan Rhizophora apiculata ditemukan di semua jenis substrat, spesies Rhizophora mucronata ditemukan pada dua jenis substrat yaitu substrat lempung berpasir dan lempung liat berpasir namun beberapa spesies hanya ditemukan di satu jenis substrat saja seperti spesies Xylocarpus granatum, Avicennia lanata, Avicennia officinalis, Bruguiera gymnorhiza dan Bruguiera sexangula.

Thalassia hemprichii is one of the seagrass as favorite food of two protected herbivores such as Green Turtle and Dugong. The existence of Thalassia hemprichii and knowing the growth rate becomes very important for sustainability of two herbivores. The study was conducted in Tanjung Benoa waters that covering three parts of the coast such as Samuh, Conrad and Tanjung beach in February until March 2017. Thalassia hemprichii leaves growth is observed consist of long and heavy growth (dry weight) and measured leaf age that has been observed such as young, half old and old leaves. The method that used to measure the growth of Thalassia hemprichii is pruning method and determination the research location using purposive sampling method. The aim of this research is explained the growth rate, biomass, and productivity of young leaves, old leaves of Thalassia hemprichii in Tanjung Benoa Bali. Measurement results of Thalassia hemprichii growth between age group of leaves has different young leaves faster growth if compared with the half old leaves and old leaves with average growth is 3.41mm/day indicates that the efficiency of this seagrass growth will decrease as the leaves age. The highest biomass values ??were found in older leaves if compared with young leaves and half-old leaves with average 0.205 gbk/m2 expected because the thick and wide leaf size will produced larger leaf biomass. The highest productivity value is found in oldest leaves in each station with average 0.028 gbk/m2/day expected morphology and different nutrient content in each leaf tissue.

Lakes are one of the surface water resources in Bali Island which supports the socio-economic activities of the community. The growing economic activities either in the tourism or agricultural sector have their effects on the emergence of various problems such as the environmental pollution, shallowness of lakes and erosions. The emergence of various pollutions and the decreased functions of the Lake Beratan is not separable from the intervention of the community living surrounding the lake so that the conservation efforts need the community participation living surrounding the lake. This is based on the idea that the success of the conservation of water resources does not only depend upon the government but the involvement of the community also becomes a key factor. This study aims to identify and analyze the participation of the community living surrounding the Lake Beratan in the conservation of water resources. The number of samples used in this study was 98 respondents gathered by means of purposive sampling in the village of Kembangmerta, the village of Candikuning I and Candikuning II which are located close to the area of Lake Beratan and the majority of the people there use the lake water for daily needs. The community participation is divided into two categories, less participations and good participations, calculated based on Likert scale while the effect of free variables such as age (X1), education (X2), income (X3), length of living (X4), and perception (X5) on bond variables were calculated using discriminating analysis. The result of the study shows that the community participation surrounding Beratan Lake in conserving water resources had been good. The differentiating variables were the age of the respondents and their incomes.

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Urban drainage is one of basic facilities and infrastructure of a town which is cincidered quite important. Agood city needs to consider the condition of the drainage system, because if a settlement is flooded, it will greatly impact the lives of the city. Buildings will be easily damage, environments will be unhealthy and settlements will turn into slumps. The case of flooding is not only in big cities but also emerged in the town of Semarapura that extents only, 5,151 km2. From the conditions on ground, puddles can still be found in some locations, so based on the fact it is necessary to issue reviewing Semarapura drainage system to improve the drainage system in the region. The study in this research has the sense of a systematic search of the drainage problems from an investigation in order to get treatment effort. The approach applied in this research was exploratory and descriptive analytical approach. Data were collected through questionnaires an in-depth interviewers with selected agencies using purposive sampling method. Data analysis was perfomed by descriptive qualitative using likert scale to measure the attidudes, opinions and perceptions of tge performance of the drainage system. The analysis was performed with the aids of SPSS version 20.0, through several stage of the test process to the data sample. The result of the study showed that the influence of the level of maintenance operation, technical management and overall was high at 93,5% with the regression equation Y = -4.874 + 0.405 X1 + 0.228 X2 + 0.089 X3 and the remaining 6.5% was influenced by other factors. From the equation it can be seen that the maintenance operations were more dominantly affected on the performance of the drainage system in Semarapura town District of klungkung compared with management and technical. The effort carried out to increase performance system of Semarapura town drainage network is to construct a structured system of maintenance operations so that it can be performed on a regular basic, establish drainage management institutions that it’s authority and responsibility can be coordinated as directed an make clear rules of management system, make repairs damage drainage infrastructure in accordance with the technical requirement.

Availability of clean water for drinking water increasingly scarce, then efforts to utilize alternative flow of river water as drinking water and raw water industry one of them is Saba River. Purpose of research is to determine the characteristic of pollution source which will be impactto the changing of water quality in physical, chemical, and biological in up, middle and down stream area of Saba River, water quality and pollution index of Saba River. Determination of samples by using purposive sampling method. Sampels were taken at six points with repetitions three times at different times. Sampels taken at two points upstream, two points middle and two points downstream. Samples were analyzed in situ and ex situ. The results showed that the activities that affect water quality physical, chemical, and biological in up, middle and down stream area of Saba River is agricultural activities, livestock, restorant, blacksmith, home stay, residential, workshops, market, laundry and industrial activities. The upstream region until middle region (T1) no parameter exceeded the quality standard, parameters that exceed the quality standard in the middle region (T2) is TSS, BOD, fosfat and fecal coliform, in the downstream which exceeded the parameters in the downstream region (H1) is BOD, fosfat, fecal coliform dan total coliform and in the downstream region (H2) is DO, BOD, COD, fosfat, fecal coliform dan total coliform. Saba River quality status based on the method pollution index in the upstream region (U1) until middle region (T1) showed good condition, middle region (T2) until downstream pollutants classified as mild.

Gracilaria sp is red alga which belong to class rhodophyceae. It can grow in shallow salt water with a general characteristic is having a cylindrical and branched thallus form. Seaweed cultivation can be performed through IMTA (Integrated Multi Trophic Aquaculture) method. The basic principle of cultivation through the IMTA method is utilizing service of the low thropic level species in marine ecosystems, such as shells and seaweed.  This method is believed to be able to overcome the environmental problems caused by cultivation activities, such as feces and uneaten feed. This research was perfomed 45 days, from February 25 to April 11, 2017. It was held at Geger Beach, Nusa Dua, Badung Regency, Bali, using a complete randomized design method that consist of three treatments and three repetition for each treatment. Treatment control (T1) consisted of 10 bunches of seaweed 100 grams without the abalone, treatement 2 (T2) consisted of 10 bunches of seaweed 100 grams and 20 abalones and treatement 3 (T3) consisted of 10 bunches of seaweed 100 grams and 40 abalones. The result showed that specific growth rate in Gracilaria sp.  was highest in treatment T1, compared to treatment T2 and T3. This was caused by the cage construction of abalone amd the present of small mesh size net to cover the seaweed  planting, which made the growth was not optimal.  However, the use of a nets system in seaweed cultivation could minimize the loss of thallus. It was proved by the survival rate of seaweed in first, second and third, that is averagely high, ranging from 90% to 100%. Physical and chemical water quality parameters are also measured, and It showed that the water quality was suitable for the cultivation of both, seaweed and abalone.