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One of the challenges in using Manning’s equation lies in accurately determining Manning’s roughness coefficient, especially due to sediment transport. The condition of sediment transport within a specific section of a river can be in equilibrium, meaning that the amount of sediment entering and exiting the segment is balanced or it can be in non-equilibrium, where there is an imbalance between the sediment entering and leaving the segment. Experiments were carried out in the laboratory to simulate both transport conditions, one involving sediment feeding (equilibrium condition) and the other without sediment feeding (non-equilibrium condition). A total of 180 mean velocity profiles were measured using an acoustic doppler velocimeter (ADV) in fixed and movable bed flows. The present experiment was combined with theoretical approaches to evaluate Manning’s coefficient in open channels under sediment transport-flow conditions and reach conclusive results. The shape of the velocity profile, u/U, for flows over a movable bed with sediment feeding is “slender” compared to those without sediment feeding. The presence of sediment transport affects the shape of the velocity profile, especially in the inner region, influencing Manning's roughness coefficient. This coefficient can be determined from two-point velocity measurements at z/H = 0.1 and 0.2 for fixed and movable bed flows with and without sediment feeding, respectively. On average, sediment feeding increases the coefficient by 19% compared to the non-sediment feeding case. [ABSTRACT FROM AUTHOR]

People have used rainwater harvesting (RWH) technology for generations to a considerable extent in semi-arid and arid regions. In addition to meeting domestic needs, this technology can be utilized for agricultural purposes as well as soil and water conservation measures. Modeling the identification of the appropriate pond's location therefore becomes crucial. This study employs a Geo Information System (GIS) based multi-criteria analysis (MCA) approach and satellite rainfall data, Global Satellite Mapping of Precipitation (GSMaP) to determine the suitable locations for the ponds in a semi-arid area of Indonesia, Liliba watershed, Timor. The criteria for determining the location of the reservoir refer to the FAO and Indonesia's small ponds guideline. The watershed's biophysical characteristics and the socioeconomic situation were taken into consideration when selecting the site. According our statistical analysis, the correlation coefficient results of satellite daily precipitation were weak and moderate, but the results were strong and extremely strong for longer time scales (monthly). Our analysis shows that about 13% of the entire stream system is not suitable for ponds, whereas areas that are both good suitability and excellent suitability for ponds make up 24% and 3% of the total stream system. 61% of the locations are partially suited. The results are then verified against simple field observations. Our analysis suggests that there are 13 locations suitable for pond construction. The combination of geospatial data, GIS, a multi-criteria analysis, and a field survey proved effective for the RWH site selection in a semi-arid region with limited data, especially on the first and second order streams. [ABSTRACT FROM AUTHOR]

The construction of a new CFPP in Indonesia, which was located next to three existing power plants and utilized an existing discharge channel, faced the problem of insufficient capacity of the existing discharge channel to deliver water to four power plants. The problem occurred not only because of the overcapacity of the cooling water flow proposed by the new CFPP but also because of the small size of the culvert located in the discharge channel. This paper discusses several methods to overcome this problem by enlarging the culvert area or by removing the culvert from the channel and replacing it with a bridge. A hydraulic study was investigated using the HEC-RAS software by utilizing inputs obtained from the existing channel geometry and flow measurement data. It was found that additional culverts on both sides with a size of 2 m x 4 m and 3 m x 1 m could reduce the water level by 1.12 m and 0.39 m, respectively. Meanwhile, removing the culvert provided a significant water level reduction of 1.39 m. Enlarging the culvert was chosen as the solution to the discharge channel capacity issue since removing the culvert would require temporarily closing the channel during construction and stopping the operation of the existing power plant. [ABSTRACT FROM AUTHOR]