$(30$ points$)$ A slug test was conducted on a cased well in the alluvial deposits of the Salt River

bed west of Phoenix, Arizona. The static water level was $5\mathrm{.}5m,$ saturated thickness $H=80m,$

perforated length $L_e=4\mathrm{.}46m,r_c=0\mathrm{.}076m,$ and $r_w=0\mathrm{.}12m.$ A solid cylinder $($slug$)$ with volume

the equivalent of $0\mathrm{.}32m$ change in water level in the well was placed below the water table.

After equilibrium was attained the cylinder was quickly removed and the water level change

was recorded with the help of a pressure transducer. These data are given in the table below.

Use Hvorslev's method to calculate manually the hydraulic conductivity $(K)$ of the aquifer.

Slug Analysis

$r_c$ is access tube internal radius

$r_s$ is perforated section external radius

$L,$ is length of perforated section

$h_o,$ is initial head, $t=t_0$

$h(t)$ is head after recovery time $t$

A is the tube or casing area $=r_c^2$

$F,$ is a shape factor $=2\frac{L}{ln(\frac{L}{r_s})}$

Analysis methods include:

;ooper, Bredehoeft, Papadopulos $(1967$ & $1973)$

The Cooper analysis considers storage but

the Hvorslev analysis is more widely used.

Hvorslev $(1951)$ Analvsis

Plot time against

Measure basic time lag T

when $ln(\frac{h_0}{h})=1$

$K=r_{{?}_{?}}(c{)}^{2}ln(\frac{L}{r_s})$

$2LT$

Time lag $T_0$ occurs when

$h=e^{-1}{h}_0=0\mathrm{.}37h_0$

If $T_0=1000$ secs for $a$

$50mm$ dia. $x1m$ length

piezometer with $38mm$ dia

access tube $K=2{10}^{-6}\frac{m}{s}$A slug test was conducted on a cased well in the alluvial deposits of the Salt River

bed west of Phoenix, Arizona. The static water level was $5\mathrm{.}5$ m$,$ saturated thickness H$=80$ m$,$

perforated length Le$=4\mathrm{.}46$ m$,$ rc$=0\mathrm{.}076$ m$,$ and rw$=0\mathrm{.}12$ m$.$ A solid cylinder $($slug$)$ with volume

the equivalent of $0\mathrm{.}32$ m change in water level in the well was placed below the water table.

After equilibrium was attained the cylinder was quickly removed and the water level change

was recorded with the help of a pressure transducer. These data are given in the table below.

Use Hvorslev$$s method to calculate manually the hydraulic conductivity $($K$)$ of the aquifer.