No abstract

The high sediment contained in the canals causes changes in the dimensions of the canals. It can reduce the cross-sectional capacity of the canals. The Baluase Irrigation Area is located in Sigi Regency, Central Sulawesi Province, with a functional area of 94 Ha. This study aims to determine the rate of sedimentation in the Baluase Irrigation Secondary canals, which is expressed in the correlation coefficient (R), which is the relationship between Sediment Discharge (Qs) and Water Discharge (Qw). Primary data were collected by direct measurements at the location by measuring canals dimensions, water level, velocity and water samples to test sediment concentration. Sediment samples were taken at 2 distances of flow depth, namely 0.2 h and 0.8 h with 8 cross sections in the longitudinal direction of the canal. From the research results, the average sedimentation rate in the Ramba secondary canal is 3,574 kg/day, while the Baluase secondary canal is 5,675 kg/day. The correlation coefficient (R) value at 0.2 h was 0.6994 and 0.8229 for a depth of 0.8 h. This shows that the relationship between sediment discharge (Qs) and water discharge (Qw) has a positive relationship between 0.6 < R < 1.0

The aim is to know the effect of bedload sediment to river hydraulics parameters. The research was conducted by taking samples in three-part of the river. Each location is taken ten cross-sections with left, middle, and right parts of the river. Bedload sediment is calculated by the grain analysis method. There are several approaches in determining the roughness: Manning, Raudkivi, Subramanya, Meyer, and Muller roughness. From the analysis results, sediment in the form of fine sediment (d ≤ 0.15 mm) located in the middle of the cross-section does not settle due to high velocity. In contrast, in the wet area, the velocity is smaller so that grain material is deposited. The relationship of bedload sediment to the morphological form of the river shows that the middle part has the most material content in grain sediment (d ≤ 0.15 mm). The wet edge has the most content in gravel and sand (d < 6 mm). The Manning equation obtained a minimum roughness of 0.0257 and a maximum coefficient of 0.0365 with an average value of 0.0311. This value is matched with the coefficient of roughness on the Manning table does not differ much, i.e., natural, straight, and meandering channels.

The two main elements of a river flow hydrograph are direct runoff and baseflow. Base flow is a flow that comes from groundwater and it is available during the rainy and dry seasons. Information of baseflow value of a watershed has an important meaning in efforts to develop and manage water resources, including the provision of clean water, irrigation systems, flood management and others. Miu watershed located in Sigi Regency often experiences natural disasters such as floods and droughts that occur almost every year, which is the research location with an area of 65,452.01 Ha. This study aims to determine the value of baseflow using the Local Minimum Method and to find out whether this method can be used for baseflow modeling in research watersheds. This study was conducted using Hydro Office software with input data in the form of daily discharge data from 2004 to 2013. The average baseflow value obtained was 5.43 m3/s. The process of calibrating the baseflow value by taking flow data in the dry season where there is no rainfall input. It is obtained that BFI have value an average of 0.89. This value indicates that the Miu watershed has high storage permeability characteristics, The Miu watershed has quite stable flow during dry periods, because the greater the BFI value, the better the water supply in a watershed. In the statistical test, the observed discharge is the discharge data from the measurement results for the period 2004-2013, while the calculated discharge is the result of the estimated base flow value obtained using the graphical method. From the results of the statistical test of RMSE and R2, the RMSE value was 0.147 and the R2 value was 0.751. Both statistical tests show that the local minimum method has a fairly good performance in modeling the base flow in the Miu watershed.