-
Carley Daines & Partners
11 Bridgewater Road
Walkden
Manchester
Project
Job Ref.
Section
Sheet no./rev.
1
Calc. by
F
Date
18/01/2016
Chk'd by
Date
App'd by
Date
SOAKAWAY DESIGN (BRE DIGEST 365/SUDS)
SOAKAWAY DESIGN
In accordance with CIRIA C697 SUDS
Tedds calculation version 2.0.01
Design rainfall intensity
Location of catchment area Manchester
Impermeable area drained to the system A = 780.0 m2
Return period Period = 30 yr
Ratio 60 min to 2 day rainfall of 5 yr return period r =
0.390
5-year return period rainfall of 60 minutes duration M5_60min =
18.0 mm
Increase of rainfall intensity due to global warming pclimate =
30 %
Soakaway / infiltration trench details
Soakaway type Rectangular
Width of pit w = 4800 mm
Length of pit l =4000 mm
Percentage free volume Vfree = 96 %
Soil infiltration rate f = 66.310-6 m/s
Base area Ab = w l = 19200000 mm2
Perimeter P = 2 (w + l) = 17600 mm
Coefficient b b = P f / (Ab Vfree) = 0.23 hr-1
Table equations
Rainfall intensity i = M30 / D
Coefficient a a = Ab / P - (A i / (P f))
Minimum depth required H = a (e(-bD) - 1)
Duration, D (min)
Growth factor Z1
M5 rainfalls
(mm)
Growth factor Z2
30 year rainfall,
M30 (mm)
Intensity, i (mm/hr)
a (mm) Min depth req
(mm)
5 0.37 8.7 1.47 12.8 153.04 -27325 514
10 0.52 12.2 1.51 18.3 109.94 -19323 720
15 0.63 14.7 1.52 22.5 89.91 -15604 864
30 0.80 18.7 1.54 28.8 57.62 -9608 1035
60 1.00 23.4 1.54 36.0 35.95 -5585 1138
120 1.21 28.3 1.52 43.0 21.52 -2905 1063
240 1.46 34.2 1.49 51.0 12.76 -1278 765
360 1.62 37.9 1.48 56.0 9.33 -641 478
600 1.82 42.6 1.45 61.9 6.19 -59 53
1440 2.28 53.4 1.41 75.2 3.13 509 0
Minimum depth of soakaway Hmax = 1138 mm
Time for emptying soakaway to half volume ts50 = Vfree Ab / (f
P) Ln((Hmax + Ab / P) / (Hmax / 2 + Ab / P)) = 1hr
17min 36s
PASS - Soakaway discharge time less than or equal to 24
hours
-
Carley Daines & Partners
11 Bridgewater Road
Walkden
Manchester
Project
Job Ref.
Section
Sheet no./rev.
2
Calc. by
F
Date
18/01/2016
Chk'd by
Date
App'd by
Date
-
DB
B
BD
2
LAP100m activity zone
Soft l
ands
cape
buffe
r to gr
eenb
elt
Railway tra
ck, Liverpo
ol/Manches
ter line
29.
25.
22.
CB
BC
CBCC
B
BC
B
Apts.
A
C
35.36.
30.
31.
28. 32.27.
26.
24.
23.
21.18. 20.
19.
9-17.
8.7.
6.
5.4.
3.
2.
1.
A
B
BB
BB
33.
34.BC
-
Carley Daines & Partners
11 Bridgewater Road
Walkden
Manchester
Project
RHINEWOOD HOTEL, GLAZEBROOK
Job Ref.
15-B-10668
Section
LARGE SOAKAWAY
Sheet no./rev.
1
Calc. by
CRC
Date
22/03/2016
Chk'd by
Date
App'd by
Date
INTRODUCTION
The large soakaway drains 15 units at 50m2 plus 750m2 of
highway
Total drained area – 1500m2
SOAKAWAY DESIGN (BRE DIGEST 365/SUDS)
SOAKAWAY DESIGN
In accordance with CIRIA C697 SUDS
Tedds calculation version 2.0.01
Design rainfall intensity
Location of catchment area Manchester Imp area drained to
soakaway A = 1500.0 m2
Return period Period = 30 yr Ratio r r = 0.360
5-yr rtn period rainfall 60 min M5_60min = 18.0 mm Increase for
global warming pclimate = 30 %
Soakaway / infiltration trench details
Soakaway type Rectangular Width of pit w = 8000 mm
Length of pit l =4800 mm Percentage free volume Vfree = 96 %
Soil infiltration rate f = 66.310-6 m/s
Base area Ab = 38400000 mm2 Perimeter P = 25600 mm
Coefficient b b = 0.17 hr-1
Table equations
Rainfall intensity i = M30 / D
Coefficient a a = Ab / P - (A i / (P f)) Minimum depth required
H = a (e(-bD) - 1)
Duration, D (min)
Growth factor Z1
M5 rainfalls
(mm)
Growth factor Z2
30 year rainfall,
M30 (mm)
Intensity, i (mm/hr)
a (mm) Min depth req
(mm)
5 0.36 8.4 1.47 12.4 148.60 -34981 480
10 0.51 11.9 1.50 18.0 107.71 -24941 680
15 0.62 14.5 1.52 22.1 88.39 -20198 820
30 0.79 18.5 1.54 28.4 56.87 -12462 991
60 1.00 23.4 1.54 36.0 35.95 -7327 1119
120 1.22 28.5 1.52 43.4 21.68 -3823 1079
240 1.48 34.6 1.49 51.7 12.92 -1671 810
360 1.67 39.1 1.47 57.5 9.58 -852 537
600 1.90 44.5 1.45 64.3 6.43 -78 63
1440 2.42 56.6 1.40 79.3 3.30 689 0
Minimum depth of soakaway Hmax = 1119 mm Time to empty half
soakaway ts50 = 1hr 27min
PASS - Soakaway discharge time less than or equal to 24
hours
-
EARTH ENVIRONMENTAL & GEOTECHNICAL
Ashbourne House, 334 Wellington Road North Stockport, Cheshire,
SK4 5DA
Tel: 0161 2824518 Email: [email protected] Web:
www.earthenvironmental.co.uk
SOAKAWAY
Site: Rhinewood Hotel, Warrington
Number: SA1
Date: 06th January 2016
Engineer: Peter Lynch
Dimensions: 1.8 X 2.5m
Total Depth: 2.0m
Job No.: A1197-16
Coordinates: SJ 69717 92487
Schematic Profile:
Log:
TOPSOIL Brown SAND Reddish brown SAND
GL – 0.50m: Black slightly silty SAND with rootlets (TOPSOIL).
0.50 – 1.10m: Brown slightly silty slightly gravelly fine to coarse
SAND. Gravel is medium to coarse and subangular of mudstone. 1.10m
– 2.00m: Reddish brown slightly silty fine to medium SAND.
Groundwater not encountered. Trial Pit complete at 2.00m bgl. Trial
pit stable at final depth.
Pictures:
SA1 Spoil
-
EARTH ENVIRONMENTAL & GEOTECHNICAL
Ashbourne House, 334 Wellington Road North Stockport, Cheshire,
SK4 5DA
Tel: 0161 2824518 Email: [email protected] Web:
www.earthenvironmental.co.uk
SOAKAWAY
Site: Rhinewood Hotel, Warrington
Number: SA2
Date: 06th January 2016
Engineer: Peter Lynch
Dimensions: 1.8 X 2.5m
Total Depth: 2.0m
Job No.: A1197-16
Coordinates: SJ 69774 92536
Schematic Profile:
Log:
TOPSOIL Brown SAND
GL – 0.50m: Black slightly silty SAND with rootlets (TOPSOIL).
0.50 – 2.00m: Brown slightly silty slightly gravelly fine to coarse
SAND. Gravel is medium to coarse and subangular of mudstone.
Groundwater not encountered. Trial Pit complete at 2.00m bgl. Trial
pit stable at final depth.
Pictures:
SA2 Spoil
-
Earth Environmental& Geotechnical Ltd
Tel / Fax: 0161 2824518 Job No: A1197Web:
www.earthenvironmental.co.uk Site: Rhinewood hotelEmail:
[email protected] Client: R P Tyson Construction
Ltd
Location Reference: SA1
Date 06/01/2016 Time Depth of
Geology in test section Sand Units Elapsed water below top of
casing
Depth to Base of Hole 2 m (secs) (m)
Hole width 1.8 m 0 1.000
Hole length 2.5 m 1 1.010
Depth to water at start of test below ground level 1 m 2
1.010
Depth to water at end of test below ground level 1.10 m 3
1.010
Depth to 75% full 1.25 m 4 1.020
Depth to 50% full 1.50 m 5 1.020
Depth to 25% full 1.75 m 6 1.020
Height to 50% depth 0.500 m3 7 1.030
Effective Storage Volume Vp75-25 2.25 m3 8 1.030
Time for water level to fall between Vp75 -25 1215 s 9 1.030
Internal surface area of hole up to 50% depth including base
8.80 m2 10 1.030
Soil Infiltration Rate, f 2.10E-04 m/s 15 1.040
30 1.040
60 1.050
120 1.060
180 1.060
240 1.100
SOAKAWAY TEST
(To: BRE 365 1991)
1.000
1.020
1.040
1.060
1.080
1.100
1.120
0 50 100 150 200 250 300
De
pth
Be
low
Gro
un
d L
eve
l (m
)
Elapsed Time (secs)
http://www.earthenvironmental.co.uk/mailto:[email protected]
-
Earth Environmental& Geotechnical Ltd
Tel / Fax: 0161 2824518 Job No: A1197Web:
www.earthenvironmental.co.uk Site: Rhinewood HotelEmail:
[email protected] Client: R P Tyson Construction
Location Reference: SA2
Date 06/01/2016 Time Depth of
Geology in test section Sand Units Elapsed water below top of
casing
Depth to Base of Hole 2 m (secs) (m)
Hole width 1.8 m 0 1.20
Hole length 2.5 m 1 1.20
Depth to water at start of test below ground level 1.2 m 2
1.20
Depth to water at end of test below ground level 1.26 m 3
1.20
Depth to 75% full 1.40 m 4 1.21
Depth to 50% full 1.60 m 5 1.21
Depth to 25% full 1.80 m 6 1.21
Height to 50% depth 0.400 m3 7 1.21
Effective Storage Volume Vp75-25 1.80 m3 8 1.21
Time for water level to fall between Vp75 -25 3420 s 9 1.21
Internal surface area of hole up to 50% depth including base
7.94 m2 10 1.21
Soil Infiltration Rate, f 6.63E-05 m/s 15 1.21
30 1.22
60 1.23
120 1.26
180 1.26
240 1.27
SOAKAWAY TEST
(To: BRE 365 1991)
1.10
1.12
1.14
1.16
1.18
1.20
1.22
1.24
1.26
1.28
0 50 100 150 200 250 300
De
pth
Be
low
Gro
un
d L
eve
l (m
)
Elapsed Time (secs)
http://www.earthenvironmental.co.uk/mailto:[email protected]
10668 Soakaway design (18.01.16)10668.20C10668.Soakaway
Design.22.03.16Exp Hole Location PlanLogsSA1 SoakawaySA2
Soakaway
