QUESTION $1$

$10$ points

A soil specimen with diameter of $70mm$ and length of $100mm$ undergoes both the constant head and falling head permeability tests. In the constant head test, the total head difference across the specimen was $171mm,$ and it takes $2253$ seconds for the outflow $($from the soil$)$ to fill up a $1,000c{m}^3$ beaker. When the same soil undergoes the falling head test, estimate the time $($in seconds$)$ for the water level to drop along a $5-$mm standpipe, from an initial total head of $287mm$ to final total head of $31mm.$