Clean water is an unlimited and sustainable need that must be fulfilled every day and meet an appropriate standard in terms of quantity and quality. The research objective in this study was to analyze the quality of water in thirty freshwater springs and twenty four brackish springs in the karst area of Buton Tengah Regency to achieve sustainable water resource management. Data on the quality of freshwater springs and brackish water springs chemically and biologically have been analyzed in the biology laboratory of FMIPA Universitas Halu Oleo, then the results are compared with the standards for water quality contained in the regulations of the Minister of Health and Government Regulation of the Republic of Indonesia. The results showed that the freshwater springs in Talaga Raya District exceeded the water quality standards for hardness parameter, while the brackish springs in Mawasangka Tengah, Mawasangka Timur, Lakudo, and Mawasangka Districts has exceeded the water quality standards for parameters of total dissolved solids, hardness, and chloride. However, these parameters are relatively easy to overcome so that the use of freshwater springs can qualify as drinking water, while the use of brackish springs should be used to meet domestic non-drinking water needs.

The Rawa Aopa Watumohai National Park area (TNRAW) is an administrative area of East Kolaka Regency and is in direct contact with the TNRAW area, so community activities to use TNRAW as business land cannot be stopped. This study aims to analyze potential TNRAW conflicts and provide direction for problem resolution. This study combined the survey method with a participatory approach with the community and TNRAW managers. The results showed several problems encountered in villages included in the TNRAW area, including encroachment and illegal logging, land sale and purchase, land certification, settlements within the area, plantations within the area, rice fields in the area, construction of facilities and infrastructure by the government, recognition of village administration in the area, allocation of village funds and waterlogging and overfishing. Community stakeholder actors have a negative influence or role in the TNRAW area. The role of the Southeast Sulawesi Provincial Public Works Office, Universities, Non-Governmental Organizations (NGOs), and the Ministry of Environment and Forestry (KLHK) as stakeholder actors is positive for both the community and TNRAW. Recommendations for problem resolution directives include: 1) increasing community participation through continuous empowerment and assistance so that adverse roles of TNRAW can be minimized, 2) increasing the role of stakeholders to coordinate with TNRAW, especially concerning land legality and community agricultural activities within the TNRAW Area, 3) solving various problems in TNRAW through mutually beneficial mechanisms between the community and TNRAW,   The solutions offered must, of course, be following applicable laws and regulations.

Abstrak: Analisis Pengaruh Temperatur Tinggi Terhadap Kuat Tekan Beton yang Menggunakan Terak Nikel sebagai Agregat Kasar. Seiring dengan pesatnya perkembangan infrastruktur, kebutuhan akan beton sebagai material struktur terus meningkat. Beton dipilih karena keuntungan dari sifat mekanik yang dapat direncanakan sesuai keinginan, terjangkau, keserbagunaan dan kemudahan perawatan dibandingkan bahan konstruksi lainnya. Di samping itu, tidak seperti kayu yang mudah terbakar atau baja yang mudah meleleh, beton termasuk material yang sangat tahan terhadap suhu tinggi. Penelitian ini bertujuan untuk mengetahui kekuatan beton yang menggunakan terak nikel setelah terekspos suhu tinggi, serta sisa kuat tekan beton terhadap variasi suhu tinggi yang diperoleh. Penelitian ini menggunakan metode quantitative dengan membandingkan dua jenis benda uji yaitu beton konvensional dan beton yang menggunakan terak nikel. Kedua benda uji direncanakan pada kekuatan K200. Kedua jenis benda uji dibakar selama masing-masing 3 jam dengan variasi suhu antara 200 – 800 oC, dengan selisih kenaikan suhu sebesar 100 oC. Semua benda uji kemudian diukur kuat tekannya. Hasil pengujian menunjukan bahwa semakin tinggi suhu pembakaran, semakin besar pula penurunan kekuatan ke dua jenis beton. Beton yang menggunakan terak nikel sebagai agregat kasar memiliki ketahanan terhadap suhu tinggi yang lebih baik dari beton konvensional di semua tingkat kenaikan suhu pembakaran. Pada suhu pembakaran tertinggi yaitu 800 oC, kuat tekan beton turun drastis dan hanya tersisa sebesar 39,90%. Kata kunci: Kuat tekan beton; terak nikel; suhu tinggi Abstract: The Analysis of  High-Temperature Effect on Compressive Strength of Concrete with Nickel Slag as Coarse Aggregate. As the rapid development of infrastructure, the need for concrete as a structural material continues to increase. Concrete was chosen because of the advantages of its customizable mechanical properties, affordability, versatility and ease of maintenance compared to other construction materials. In addition, unlike wood that is flammable or steel which melts easily, concrete is a material that is highly resistant to high temperatures. This study aims to evaluate the strength of concrete using nickel slag after high temperature exposure, as well as the remaining concrete compressive strength against the variation in high temperature obtained. This study uses a quantitative method by comparing two types of test samples, namely conventional concrete and concrete using nickel slag. Both types of samples were designed at the strength of K200. These samples were burned for 3 hours each with a temperature variation between 200 - 800 oC, with an increase of 100 oC, and then measured for compressive strength. The test results show that the higher the combustion temperature, the greater the decrease in strength for the two types of concrete. Concrete that uses nickel slag as coarse aggregate has better high temperature resistance than conventional concrete at all levels of rising combustion temperatures. At the highest combustion temperature, which is 800 oC, the compressive strength of concrete drops dramatically and only 39.90% remains. Keyword: Concrete compressive strength; nickel slag; high temperature

The Lupia Village irrigation network was formed in 1981 through farmer groups from the results of non-governmental organizations. Currently the government has given attention and assistance both through the village fund budget and central government funding assistance, however, there is still a need for program sustainability from related parties. The results of the identification were carried out, namely that there were still few people who did not understand about the more effective use of irrigation water, so that there was always a crop failure where other plots of rice fields had excess water while the farthest plots did not get water. The area of land used by the community is currently around + 35 hectares, but the available land and the potential to be used as rice fields are around + 90 hectares, so that what has not been functioned as rice fields is about + 55 hectares. Seeing this condition, it is very potential to be developed to be able to increase the production of rice fields in Lupia Village, from this potential, the Lecturer of the Faculty of Engineering, Halu Oleo University as part of the Tridarma of Higher Education, carries out community service activities through the transfer of knowledge so that the community can develop, increase production, and improve community welfare, especially the residents of Lupia Village, Kabangka District, Muna Regency. The methods used are socialization, technical guidance, training on procedures for implementing technical irrigation canal development so that water is not wasted and can be fully utilized by farming communities. The expected result is that the community can increase the yield of lowland rice production. Seeing the potential of Lupia Village in Kabangka District, it is hoped that the program can be carried out continuously so that it can increase income and a better standard of living for its people.

Indonesia is a maritime country where the sea area is larger than the land area and consists of a group of islands stretching from west to east. Inter-territorial accsebility can become faster and smoother by structur long span bridges. In the deep sea and tidy ground conditions allow use of pile foundatio, however the floating foundation is an option that can be taken. The purpose of this paper is to propose the concept of a long-span bridge floating foundation that is capable and stable to support the load or forces that work.