Ambala
Explanation
A water divide (or watershed) is an elevated area, such as a mountain, ridge, or upland, that separates two distinct drainage basins. The separation between the Indus river system and the Ganga river system is marked by a specific upland region in the plains of Northern India.
Geographical Analysis:
- Ambala: This city is situated on the upland that acts as the water divide between the Indus and the Ganga river systems. Rivers flowing to the west of this divide join the Indus system, while those flowing to the east join the Ganga system.
- Haridwar: Located where the River Ganga descends from the Himalayas into the plains. It is part of the Ganga basin, not the divide.
- Allahabad (Prayagraj): Situated at the confluence (Sangam) of the Ganga, Yamuna, and the mythical Saraswati. It lies deep within the Ganga basin.
- Delhi: Located on the banks of the River Yamuna, which is a tributary of the Ganga. While close to the divide, the specific geographic marker for the separation of the drainage systems is Ambala.
Key Takeaway:
Ambala serves as the critical water divide separating the westward-flowing Indus drainage system from the eastward-flowing Ganga drainage system.