Estimation of flow depth at gaula barrage, kathgodam using 2d hec-ras hydraulic model

The Gaula Barrage, which is situated at latitude 29°16′18′ N and longitude 79°32′51′ E over the Gaula River in Kathgodam, Nanital district, Uttarakhand, India is crucial for flood control and irrigation. For effective barrage operation and hydraulic planning, accurate flow depth estimation under various hydraulic conditions is crucial. In order to assess the impact of discharge, gate operation and Manning's roughness coefficient on maximum flow depth, a two-dimensional hydraulic model of the Gaula Barrage was created in the current study using HEC-RAS 6.5. Twenty-seven simulation scenarios were created by simulating three discharge conditions (500, 1500 and 3250 m³/s), three Manning's roughness coefficients (0.030, 0.035 and 0.040) and three gate operating circumstances (fully open, partially open and fully closed). The results showed that maximum flow depth increased with increasing discharge, increasing Manning's roughness coefficient and decreasing gate opening. The maximum flow depth of 11.747 m was observed under a discharge of 3250 m³/s, fully closed gate condition and Manning's roughness coefficient of 0.040, whereas the minimum flow depth of 3.521 m occurred under a discharge of 500 m³/s, fully open gate condition and Manning's roughness coefficient of 0.030. The study provides a reliable decision-support tool for irrigation and water resource authorities to optimize barrage gate operations and improve flood management strategies.