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Croughton Fishing Lake : Constant rate tests (recorded on transducer) BH03 Base 12.42 mbtoc WL dip 6.465 mbgl WL dip 6.80 mbtc Constant rate test @ 10 l/s for 25.47 secs End test 11:51 NB: Transducer time 1 hour ahead BH02 Base 10.025 mbtoc 9.625 mbgl WL dip 3.03 mbgl WL dip 3.43 mbtoc Constant rate test @ 10 l/s for 28.12 secs BH01 Base 21.06 mbtoc WL dip 4.59 mbgl WL dip 4.165 mbtoc Constant rate test @ 10 l/s for 44.65 secs (fill bucket)
Croughton Fishing Lake : Fall and rising head tests BH03 1:15 pm (Transducer reading 2.15 pm) Dip 6.75 mbtoc In 6.80 1 min 6.80 8 min Out 6.89 30 secs 6.83 3.30 secs In 6.825 30 secs 6.825 3.30 secs BH02 3.15 pm (Whale pump) Rate 1 litre = 10 secs, checked at 15 mins, same 1 min 3.77.5 2 min 3.82 3 min 3.83.5 4 min 3.84 5 min 3.845 6 min 3.85 7 min 3.857 8 min 3.862 9 min 3.865 10 min 3.86 12 min 3.86 14 min 4.87 16 min Stopped 16.2 min .30 17 min .46 BH01 3.57 pm (Whale pump) 0.25 min 5.10 0.6 5.55 1.3 5.79 2.0 6.07 2.3 6.21 4.0 6.5 Recover 0.3 5.5 1.1 5.34 1.3 5.28 2.0 5.2 2.3 5.14 3.0 5.09
10 litres 1.57 Dip recovered to 3.46 mbtoc Test 2 Flow rate 1.54 mins 10 litres 1.54 BH01 Whale pump in transducer Dip 4.55 mbtoc Flow rate 2.18 mins/10 litres
In 2 Chart 1
Page 1
0.01
0.10
1.00
0.00 0.05 0.10 0.15 0.20 0.25
Elapsed Time (minutes)
H/H
o
Variable head permeability test Out Site : Croughton Borehole:Depth below top of casing/standpipe to : Project No :(a) bottom of borehole : 13 m Date : 31/11/2011 Sheet 1 of 1(b) bottom of casing : 12.7 m Ground Level (OD): m Contractor:(c) top of filter material : 12.7 m Weather : Fine(d) center of piezometer tip : 0 m Type of test : Falling Head Permeability(e) initial ground water level : 6.3 m Diameter of casing/standpipe : 0.05 mHeight of casing/standpipe above surface : 0.3 m Length of filter: 6.0 m Dia. of filter : 0.05Elevation of casing/standpipe above surface : m (OD) Type of piezometer : L/D = 40.00Test Record
Start time 03:36 Depth to Drawdown Drawdown Calculationwater level (Ho) Ratio Shape Factor See attached sheet
hh:mm:ss min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2
Variable head permeability test Recovery/ Falling head Site : Croughton Borehole:Depth below top of casing/standpipe to : Project No :(a) bottom of borehole : 20 m Date : 31/10/2011 Sheet 1 of 1(b) bottom of casing : 14 m Ground Level (OD): m Contractor:(c) top of filter material : 14 m Weather : Fine(d) center of piezometer tip : 0 m Type of test : Falling Head Permeability(e) initial ground water level : 4.59 m Diameter of casing/standpipe : 0.05 mHeight of casing/standpipe above surface : 0.3 m Length of filter: 6.0 m Dia. of filter : 0.05Elevation of casing/standpipe above surface : m (OD) Type of piezometer : L/D = 40.00Test Record
Start time 03:36 Depth to Drawdown Drawdown Calculationwater level (Ho) Ratio Shape Factor See attached sheet
hh:mm:ss min m m (H/Ho) Cross Sectional Area A = 2.0E-03 m2
Where r = radius of influence (m) 3000 for radial flowC = constant = 1500 for trenches 1500-2000 for trenchesh = drawdown (m)k = hydraulic conductivity (m/s)rw = radius of working area (m) = 109 m
Head expected min maxHeight of water table at radius of influence H 9 m 38 42 mHeight of water table at well hw 0.5 m 38 42 m
ConductivityHydraulic conductivity of aquifer K 30 m/d m/d
RadiusLength of trench x 270 m m (Figure adapted from Mansur & Kaufman, 1962)
Distance to line source, equal to radius of influence R0 252 m 250 350 m The following assumptions apply to this equation- the slot is infinite in length
Is R0/H greater than or equal to 3 ? Yes Yes Yes - R0/H greater than or equal to 3- the aquifer is unconfined
Total discharge from wellpoints Q 2556.60 m3/d ####### ####### m3/d - the aquifer is homogeneous, isotropicand of uniform thickness- the Dupuit Forcheimer assumption is valid- the aquifer has reached steady state conditions- the initial water table is horizontal
(Mansur & Kaufman, 1962)Data sources (to complete an audit trail)Height of water table at radius of influence HHeight of water table at well hw
Hydraulic conductivity of aquifer KLength of trench xRadius of influence R0
10) Partial penetration by a single row of wellpoints of an unconfined aquifer midway
between two equidistant and parallel line sources
⎥⎦
⎤⎢⎣
⎡−⎟
⎠⎞
⎜⎝⎛ −
+= )()(27.073.0 22
0w
w hHRKx
HhHQ
Theis tier drawdon calcs, 10.Trench with flow 2 sides(UC), 14/12/2011