The problem of flooding is something that often occurs during the rainy season, and its coverage area has expanded not only to areas that are used to flooding but also to the surrounding areas. South Kalimantan Province’s Hulu Sungai Tengah Regency and a number of its districts had a flood disaster to start the year 2021. Tilahan or Hanntak is the Meratus Mountains Region which is the origin of the floods due to the overflow of the Benawa River and the continuing flow of the Barabai River. The practice of illegal logging in the Meratus Mountains Region is still rife. On January 14, 2021, extreme rainfall occurred, which caused flooding in the South Kalimantan region. Low water absorption into the ground is one of the causes of flooding when heavy rains occur for a long duration. In this study, infiltration in the Hantakan Sub-District, Hulu Sungai Tengah, will be measured to examine the infiltrated water rate. Primary data from a direct survey of the research region was collected to assess the infiltration rate, and the Horton technique was used to analyze it. Based on the test results and the results of the analysis of counts at nine points, in test 1, there were four points with very slow classification, two points with moderate classification, two points with a rather fast classification, and one point with fast classification. Whereas in test 2, there were five points classified as very slow, one as medium, and three fast.

Abstract

Gelam wood (Melaleuca cajuputi Powell) is one of the essential raw materials for traditional foundations in Kalimantan, which is widely available along the wetlands. It plays an important role in supporting the construction of houses and other infrastructure in Indonesia. Consequently, there is a need for sustainable gelam wood cultivation in Kalimantan. Presently, it is not only used in the development of wetland stilt housing, but also for the interior of the house. Therefore, this study aimed to identify the pattern of using gelam wood as a foundation structure and its potential. The qualitative design method was used with an interview survey and literature review. The result showed that the patterns of using gelam wood as a foundation are as follows; 3-6 m length for simple buildings or 1-story houses, 7-10 m length for 2-story buildings or highrise buildings, and 3-4 m length for road construction. The diameter of gelam wood used varies between 8-15 cm. Furthermore, the potential use is very large, where the need for residential foundations in Banjarmasin City is approximately 30000 m3 in 1 year, and an average of 14000-20000 are needed for 1 road construction project, not including those used for other structures