For Engineers involved in planning and construction of water resources building, hydrology becomes very important data. In terms of planning stage in water resources especially waterworks, it is known that design flood discharge closed to field realistic conditions is often needed in order that a planned construction is able to control flood discharge. Several previous researches in choosing flood discharge selection method have diverse depending on observed watershed. One method in determining selected flood discharge by verification using Creager diagram, by comparing discharge calculation results of several Synthetic Unit Hydrograph (SUH) with infrastructure flood discharge (AWLR result) in observation point. This research aims to obtain  the most suitable synthetic unit hydrograph and close to analysis result of measured discharge frequency, and Creager diagram in Kelara watershed (DAS). Based on the calculation of design flood discharge according to rainfall data using synthetic unit hydrograph of Nakayasu, ITB I, ITB II, and SCS (HEC-HMS) as well as the calculation of design flood discharge according to collected data, it is concluded that the synthetic unit hydrograph method closest to design flood discharge with measured discharge rate and Q1000 rate of Creager diagram is SCS. Flood discharge rate obtained according to HSS SCS method using HEC-HMS  4.8 application in period of 2 years  is 658,40 m3/s, 25 years is 682,70 m3/s, 50 years is 787,00 m3/s, 100 years is 885,70 m3/det, and 1000 years is 1202,60 m3/s

This research is a field study conducted in the estuary Jeneberang river. The estuary, the transitional zone formed between the river environment and the marine environment. In this region, there is the mixing of seawater with fresh water that has its own uniqueness with fluctuating salinity. This research aims to see the pattern of salinity distribution and temperature in the area of Jeneberang estuary on the tide and receding conditions. Data retrieval channeled on the area of Jeneberang estuaries with a distance between points 200 m using the ADCP (Acoustic Doppler Current Profiler) and CTD (Conductivity Temperature Depth) tools. The results showed an increase in salinity at Jeneberang estuary, which was influenced by surface and river bed.

Breakwater overtopping catcher model is a breakwater or shore protection model, which can accommodate or catch wave overtopping. This breakwater model is different from most other conventional breakwater models, at the back of this breakwater model, an opening is made to form a reservoir. This reservoir serves to collect overtopping wave, which is then collected and released back to the sea through an energy conversion process. How many waves overflow at the peak of the breakwater model is strongly influenced by several factors, one of which is the wave characteristics. This research was carried out experimentally to determine the characteristics of the waves, especially the influence of wave steepness to the wave reflection coefficient. The experiment was carried out in a wave flume with regular wave generation. Variations of research carried out on variations in the model that is slope and freeboard and wave variations that is period and wave height. The results of the study show that the wave reflection coefficient decrease with the increase of wave steepness, it is also seen that steep slopes produce the largest wave reflection coefficient.

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 m3/s and in the Mangalarang sub-watershed are 886.82 m3/s. The flood overflow of the Tallo River spread over 6.48 km2 of Manggala District, 0.31 km2 of Rappocini District, 4.24 km2 of Panakukang District, 3.37 km2 of Tallo District, 11.59 km2 of Tamalanrea District and 0.01 km2 of Biringkanaya District. The total area of flood distribution is 26 km2. 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 m3 and a maximum capacity of 5.31 million m3. The construction of this retention pond can reduce 17.7 km2 of flood-affected area.

The Bila River is one of the rivers in South Sulawesi, especially in Sidrap Regency which almost every year experience river overflows that cause flooding in the area around the river and cause losses to the community trying to analyze the flood of the river Bila with a mathematical model. The method used is to perform hydrological calculations with the help of the HEC-HMS application and simulation of flood discharge with the help of the HEC-RAS application. The results obtained are based on the results of running the HEC-RAS application with a design flood discharge of Q20 yr = 1518.10 m3/s. Recommendations for handling the flood of the Bila. River in the short, medium, and long, namely the addition of top embankments at the point of overflow, installation of control gates on tributaries and construction of retention ponds. Short and medium term amounted to 812.57 Ha and for long term handling amounted to 829.26 Ha.