If the drained area is 50 acres, determine the discharge for a collector drain receiving water in Problem 17.10. C = 0.91.

Problem 17.10

For the pipe drains of Problem 17.8 on the impervious surface, the length of drain is 8300 ft. The average water-table gradient is 0.008. Determine the peak discharge due to deep percolation and upland slope and the size of the drain for n = 0.011.

Problem 17.8

If the drains in Problem 17.7 are located on the impervious surface, determine the spacing of the drains so that the water table does not rise more than 2 ft above the drains.

Problem 17.7

The following conditions were observed for an agricultural drainage system.

1. Vertical distance from impervious layer to drains = 30 ft

2. Maximum water table above drains = 6 ft

3. Average hydraulic conductivity = 7.5 in./hr

4. Infiltration rate = 3 in./hr

5. Runoff = 40%

6. Irrigation schedule as per the following table

Determine the drain spacing so that the water table does not build up more than 1 foot above the drain.