APPENDIX B: RETENTION BASIN MODEL
The following model of the retention basin to be constructed on the EOD pad
was developed by M.R. Walsh and E.J. Chamberlain of CRREL. The model assumes
input from the dredge at 382 m3/hour, with a 4:1 water-to-saturated-soil ratio. The
following are the parameters on which this model is based:
Hydraulic conductivity of the 152-mm compacted liner = 58 106 mm/sec (Cor-
rected for 15 C).
No compaction of sludge layer (and associated decrease in hydraulic conductiv-
Three-hour settling time between pumping and decanting over weir.
Remove 7.6 cm/hour from height of weir for each of first four hours (Hours 12
15). Fifth hour (Hour 16) is a decanting drain.
Ref.: Annual precipitation in Anchorage area ≈ 38.9 cm (15.3")/yr.
7.3-m- (24') long weir.
k = 1.5 104 cm/sec.
The following are conditions set on the model:
Site size: 9680 m2 (≈ 2.5 acres)
Water in per eight-hour day @ 382 m3/hour: 2850 m3
Saturated sludge pumped per day: 610 m3
Sludge depth per day, 0.8-ha site: 0.075 m (75.4 mm)
Water depth per day, 0.8-ha site: 302.4 mm
Water depth per hour, 0.8-ha site: 37.9 mm
Equations used throughout this model and given following the model.