Canal escapes: Which statements about escapes provided in canal systems are correct?

Introduction / Context:
Escapes are controlled outlets provided in canals to dispose of surplus flows safely during floods, regulator failures, or emergency drawdowns.

Given Data / Assumptions:

• Canal reach subject to occasional surplus.
• Availability of natural drains or rivers to receive excess water.
• Design must ensure safe conveyance without overtopping.

Concept / Approach:
Properly designed escapes protect banks and structures by releasing excess water. Their capacity, alignment, and outfall into natural drainage are integral to system safety.

Step-by-Step Solution:
Confirm role as safety valves (prevents overtopping).Ensure capacity adequate (not less than canal flow at that reach).Lead discharge to natural drainage; align along favorable contours to minimize excavation and erosion.

Verification / Alternative check:
Design manuals specify escape capacity comparable to or exceeding canal capacity depending on operational needs and hydrologic risk, and outfalls are set into drains with adequate capacity.

Why Other Options Are Wrong:
Here, each individual statement is correct; hence “All the above” is the best choice.

Common Pitfalls:
Providing undersized escapes; discharging onto unprotected ground; poor alignment causing erosion.

Final Answer:
All the above