INTEK Jurnal Penelitian Vol. 8, No. 1, pp. 47-53, April 2021 47 DOI : http://dx.doi.org/10.31963/intek.v8i1.2811 The Revitalization of Makassar Urban Drainage System Based on Eco Drainage Retention Pond Abstract- One of the causes of flooding in Makassar City is the management of the water system that is not optimal. It is necessary to arrange a drainage system to overcome flooding in Makassar City. In this study the topography on Catchment area analysis, analysis of hydrology and hydraulics analysis. Modeling the distribution of flood performed using HEC-RAS applications. This research was conducted in the Tallo watershed which consists of the Upper Tallo sub-watershed and the Mangalarang sub-watershed. The results of the analysis of flood discharge in the Tallo Hilir sub-watershed are 523.76 m 3 /s and in the Mangalarang sub-watershed are 886.82 m 3 /s. The flood overflow of the Tallo River spread over 6.48 km 2 of Manggala District, 0.31 km 2 of Rappocini District, 4.24 km 2 of Panakukang District, 3.37 km 2 of Tallo District, 11.59 km 2 of Tamalanrea District and 0.01 km 2 of Biringkanaya District. The total area of flood distribution is 26 km 2 . The solution to overcome the flooding of the Tallo River with an environmentally sound drainage system, it is necessary to plan the construction of a retention pond in Tamalanrea District, with a normal total storage volume of 2.48 million m 3 and a maximum capacity of 5.31 million m 3 . The construction of this retention pond can reduce 17.7 km 2 of flood- affected area. Keywords— Flood; Hydrology; Tallo River I. Introduction One of the main causes of inundation and flooding in urban areas is the occurrence of changes in land use patterns that are not followed by the arrangement of the drainage system [1]. The development of the area is no longer in accordance with spatial planning or the concept of sustainable development resulting in changes in land use patterns so that low areas and riverbanks become residential areas [2]. Almost every year the flood disaster in Makassar occurs at every arrival of the rainy season [3]. The worst flooding in the last decade in Makassar City occurred in 2019 which submerged 4 sub-districts, namely Panakukang District, Manggala District, and Biringkanaya District as high as 50 cm to 200 cm. The main cause of the flood was due to the relatively high intensity of rainfall on January 21 and 22, 2020 so that the Tallo and Jeneberang Rivers were unable to accommodate the flood discharge [4]. Floods in Makassar City are not only influenced by the relatively high intensity of rainfall, topographical conditions in the form of a basin, increased flow discharge, changes in land use patterns and sea water tides, are also influenced by the inadequate drainage system, although the city government has programmed and building infrastructure but the problem of flooding is still a serious problem [5]. Ujung Pandang District has not been free from the threat of flooding and inundation, so that drainage arrangements are needed as city infrastructure that is useful for draining excess water in an area [6]. Floods and puddles in a residential area still occur in many cities in Indonesia. Floods or puddles in an area occur when the drainage system is unable to accommodate the flowing discharge. In urban areas, drainage functions to drain parts of the city's administrative area and urban areas from puddles of water, both from local rain and overflowing rivers that pass through the city. River revitalization itself is an effort to restore river functions which include functions as irrigation and ecological functions [7]. River revitalization is a concept to correct the previous concept of river development [8]. The drainage system as an integral part of the water management system, the drainage system revitalization program uses a participatory approach with the aim of changing people's behavior towards the importance of a good drainage system [9]. Riswal Karamma 1,a,* , Rita Tahir Lopa 1,b Mukhsan Putra Hatta 1,c 1 Civil Engineering Department, Hasanuddin University, Makassar Indonesia *,a riswalchiwal@gmail.com (Corresponding Author)