Upstream Slope of an Earth Dam under Steady Seepage Condition

When water flows through the soil in an earth dam, it creates seepage forces that can cause instability of the dam. To ensure the stability of the dam, it is necessary to design the dam in such a way that it can withstand the seepage forces.

Equipotential Line

The equipotential line is a line that connects points in a field where the potential is the same. In the case of an earth dam, the equipotential line represents the line of equal potential on the upstream slope of the dam. This line is important in determining the seepage forces that act on the dam.

Phreatic Line

The phreatic line is the line that separates the saturated and unsaturated zones in the soil. It represents the water table in the soil.

Flow Line

The flow line is a line that represents the path that water takes as it flows through the soil. It is often used to determine the direction and velocity of seepage flow.

Seepage Line

The seepage line is the line that represents the path that water takes as it flows through the soil under steady seepage conditions. It is often used to determine the seepage forces that act on the dam.

Conclusion

In conclusion, the upstream slope of an earth dam under steady seepage condition is represented by the equipotential line. This line is important in determining the seepage forces that act on the dam, and it is essential in designing a dam that can withstand these forces.

Answer is b that is phreatic line not equipotential line..
because phreatic line is the top most line of flow in sepage from earthen dams below the phreatic line is a equipotential line and Also phreatic line is also a equipotential line.
so appropriate answer is phreatic line