Let Y = Depth

Let Z = Exit Velocity

Let X = Cross Sectional Area of the Hole

Cross Sectional Area of the Cylinder:                       

5Y+10(X)

5 * 50 +10 ( Initial Depth = 50)

260 * X cm^2

Z = SQRT(1960*Y)  cm/sec

Volume of the Cylinder:

50 cm * (260 * X) cm^2

13,000 X (cm^3)

Multiply Z by the interval of time. Subtract this from 13,000 X (cm^3). This will give you how much water is left in the cylinder during the time period. Divide this by  260 X cm. This will give you remaining Depth in cm. Repeat.

Assuming X=1

Time    -    Depth

0 sec           50 cm

10 sec       37.97 cm

20 sec       27.48 cm

30 sec      18.5 cm