Lecture 26

Slug Tests

Fetter 7.5.1 & 7.5.2

Aquifer tests expensive, hard to replicate, personnel intensive.

May need to treat contaminated water.

Slug Tests

	Can determine many point source K’s.
	Simpler and quicker than aquifer tests.
	Useful for small scale studies.
	Good in low K layers (waste storage).

Methods

	Add or withdraw instantaneously quantity (slug) of water to/from a well.
	Measure water level change through time.

Cooper - Bredehoeft - Papadopulos Method - Confined

(Cooper and others, 1967)

(Papadopulos and others, 1973)

1) Confined aquifer

2) Fully penetraing well

Add or remove known volume of water to well rapidly.

 Initiate head change.

 Measure head as it returns to equilibrium.

Figure 7.18 - Well into which a volume, V, of water is suddenly injected for a slug

test of a confined aquifer.

Figure 7.20 - Field-data plot of H/H_o as a function of time for a slug-test analysis.

	T - transmissivity (ft/s) (cm/s)
	t - time (sec)
	rc - radius casing (ft) (cm)
	S - storativity
	rs - radius screen (ft) (cm)

2) F() type curves for values of this function in appendix.

Use same scale paper for field data and type curves.

3) Place type curves over field data.

	- keep arithmetic axes coincident
	- match to type curve value with same curvatures

4) Find time (t₁) value when

	read t (seconds) from x axis field data

5) Calculate storativity

Fetter Example p. 246-247

Slug of water is injected.

 Cooper Method

ENV 302 - Lectures