A $4 \times 4$ group pile, with each pile 20 m long and 500 mm in diameter, is installed in a square pattern in a clayey soil, as shown in the figure. The average unconfined compressive strength of the soil is $100 \mathrm{kN} / \mathrm{m}^2$, and the adhesion factor is 0.8 . Neglect the bearing at the tip of the piles. For a group efficiency factor of 1.0 , the centre to centre spacing (s) of the piles (in m ) would be ________ (round off to two decimal places).
In the context of the effect of drainage density on the run-off generation and the hydrograph at the catchment outlet, all other factors remaining the same, pick one or more CORRECT statement(s) from the choices given below.
A 60 cm diameter well completely penetrates a confined aquifer of permeability $5 \times 10^{-4} \mathrm{~m} / \mathrm{s}$. The length of the strainer (spanning the entire thickness of the aquifer) is 10 m . The drawdown at the well under steady state pumping is 1.0 m . Assume that the radius of influence for this pumping is 300 m .
The discharge from the well (in litres per minute) is ________ (round off to the nearest integer).
The peak of flood hydrograph due to a 3 -hour duration storm in a catchment is $180 \mathrm{~m}^3 / \mathrm{s}$. The total rainfall depth is 6.6 cm . It can be assumed that the average infiltration loss is $0.2 \mathrm{~cm} / \mathrm{h}$. There are no other losses. The base flow is constant at a value of $30 \mathrm{~m}^3 / \mathrm{s}$.
The peak value of the 3-hour unit hydrograph for this catchment (in $\mathrm{m}^3 / \mathrm{s}$ ) is ________ (round off to the nearest integer).