RFI - ADG1451.22 Dewatering Management Plan_Rev0_28.02.23

Cone of depression

 

DER requires @ preliminary assessment of the radial extent of the cone of depression and pumping

rates and times for all dewatering operations in ASS areas.

Empirical methods to calculate the radial extent of the groundwater cone of depression and
pumping rates and times for dewatering operations are outlined in Appendix E of @) Treatment and
maenegement of soils and water in acid sulfate soil landscapes 1.59 MB (Published July 2011, Revised

June 2015)

Calculator

Input

Length of excavation 35
(metres):
Width of excavation 30
(metres):
Required groundwater 23
drawdown (metres):
Saturated thickness of the,
unconfined aquifer!
(metres):

Hydraulic conductivity of
the aquifer (K) (metres
per second):

0.0000949

4
=
&

Results

Effective radius of
pumping well, R.
(metres):

Radius of influence of
dewatering, R, (metres):
(i.e. radius of the cone of
depression)

Total pumping rate (litres
per second):

Time taken to establish
the cone of depression
(hours):

m/sec

18m

67m

9l/sec

76hrs