An emergency water reserve is stored for 2 hours in the elevated reservoir.
At Hub and Mangla hatcheries tube wells only supply water for the hatchery component. Therefore 2 units of pump are recommended at each site, and all pumps should have the capacity of 5 l/s. This also provides a better utilization of pumping capacity when the water consumption is at its minimum. At Tarbela hatchery the ponds are also filled from tube wells and therefore one tube well with a capacity of 10 l/s is enough. In case of engine failure one of the pond tube wells can also supply water to the hatchery.
Daily maintenance should be scheduled so only one pump is considered to be out of operation at once. During the maintenance period one unit of pump with the capacity of 5 l/s operates. The remaining water demand is satisfied from the reservoir.
| 2 hours × 3.3 l/s - 8.3 - 5 l/sec | = | 23.8 m3 |
| 2 hours reserve water at 8.3 l/sec | = | 59.8 m3 |
| Volume of the reservoir = | 83.6 m3 |
The recommended live storage capacity of the elevated reservoir is 84.0 m3
