Water stands upto height $\text{'}h\text{'}$ behind the dam as shown in the figure. The front view of the dam gate is also shown in the adjoining figure. Density of water is $\text{'}\rho \text{'}$ and acceleration due to gravity is $\text{'}g\text{'}$. If atmospheric pressure force is also considered, the point of application of total force acting on the dam due to water above $\text{'}o\text{'}$ is_____