Outlet discharge: wheat and rice, 10000 ha

Method. The kor (critical) watering must be given to the crop within the kor period, so the outlet discharge for a crop is

$$Q = \frac{A\,d}{T\times 86400}$$

where $A$ = area of the crop (m$^2$), $d$ = kor depth (m) and $T$ = kor period (days).

Areas: wheat $= 0.30\times 10000 = 3000$ ha; rice $= 0.15\times 10000 = 1500$ ha.

Wheat ($T = 4\times7 = 28$ days, $d = 0.135$ m):

$$Q_w = \frac{3\times 10^7\times 0.135}{28\times 86400} = 1.674\ \text{m}^3/\text{s}$$

Rice ($T = 3\times7 = 21$ days, $d = 0.19$ m):

$$Q_r = \frac{1.5\times 10^7\times 0.19}{21\times 86400} = 1.571\ \text{m}^3/\text{s}$$

Wheat (rabi) and rice (kharif) are grown in different seasons, so their kor periods do not overlap and the outlet is designed for the larger discharge.

Answer: outlet discharge = 1.67 cumec (wheat governs; if both crops had to be watered together, the total would be 3.24 cumec).