TM 5-814-9
(j) Rainfall falling on open basins, Q10
V1 = 90 ft x 285 sf x 7.48 gpcf x l fill
1) Estimate surface area of dual-cell
V1 = 191862 gal (726198L)
sediment basin
L x W x 2 = 150 ft x 50 ft x 2 =
(b) Bath overflow volume, V2:
15,000 sf
V2 = Bath weir overflow rate x (wash
2) Estimate surface area of equalization
period + clean up)
basin
L x W = 300 ft x 300 ft - 90,000 sf
V2 = Q2 x Tw = 960 gpm x 240 min
3) Estimate surface area of sand filters
V2 = 230400 gal (872064L)
L x W=300 ft x 150 ft = 45,000 sf
(c) Wash station volume, V3:
4) Estimate surface area of washwater
supply basin
V3 = Wash station flow rate x wash period
L x W = 300 ft x 300 ft = 90,000 sf
V3 = Q3 x Tw = 720 gpm x 180 min
Then: Q10 = C x I x AB/143560 sfpA
Q10 = 1.0 x 2.0 x 240,000 sf/
V3 = 129600 gal (490536L)
43560 sfpA
(d) Entrance trench flusher volume, V4:
Q10 =
11 cfs or 4937 gpm
(18686 Lpm)
V4 = trench flush flow rate x cleanup
(k) A summary of computed flows is pre-
period
sented in Table A-3.
V4 = Q4 x K = 75 gpm x 60 min
Overflow rate, Qover:
Using equation 6-5, calculate the sedi-
V4 = 4500 gal (17032L)
ment basin overflow rate during the
washing period. The designer assumes
(e) Bath flusher volume,
that the entrance preparation area trench
flusher, represented by Q4, and the bath
V5 = bath flusher flow rate x cleanup
flushers, represented by Q5, are not in
period
operation after the bath is filled and,
therefore these values are not used in the
V5
Q5 x k = 3000 gpm x 60 min
calculation. Apply the appropriate usage
factor at each flow source. Then,
V5 = l80000 gal (681300L)
Qover = U2Q2 + U3Q3 + U6Q6 + U7Q7
(f) Wash station trench flusher volume, V6:
Qover = 0.90 (960 gpm) + 0.80 (720
gpm) + 0.20 (225 gpm) +
V6 = trench flusher flow rate x (wash
0.30)(120 gpm)
period + clean-up)
Qover = 1581 gpm (5984 Lpm)
V6 = Q6 x Tt = 225 gpm x 240 min
(4) Volumes. Using equations defined in chapter 6,
the designer computes the various component
V6 = 54000 gal (204390 L)
volumes for the following selected average
daily conditions:
(g) Interior wash water volume, V7:
Clean-up period, K
60 min
V7 = Interior wash flow rate x wash period
Daily wash period, Tw
180 min
V7 = Q7 x T = l2 gpm x l80 min
2
Total Wash and clean -up T
240 min
V7 = 21600 ga1 (81756L)
Storm Duration, Ts
60 min
(h) Clean-up yard hydrant volume, V8:
(a) Earth volume drained, V1: Assume only
one bath fill/flush per wash period.
V8 = yard hydrant flow rate x cleanup
period
Then, V1 = Bath volume x Number of fills
A-13
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