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.
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.
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.