The GATE Grind

GATE 2019 CE (CE2) – Question 24

Hydrology · Reservoir capacity, flood estimation and routing, surface runoff models · 1 mark · Multiple choice

Reservoir routing converts an inflow hydrograph with peak $P_I$ at time $t_I$ to outflow with peak $P_O$ at time $t_O$. Which relationship is correct?

  1. $P_I<P_O,\ t_I<t_O$
  2. $P_I<P_O,\ t_I>t_O$
  3. $P_I>P_O,\ t_I<t_O$
  4. $P_I>P_O,\ t_I>t_O$

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Correct answer: (C) $P_I>P_O,\ t_I<t_O$

Explanation

Reservoir storage attenuates and delays a flood wave. The outflow peak is therefore below the inflow peak and occurs later: **PI>PO andtI<tO,C**. This is the usual storage-routing response assumed in the question.