027002 Wharfe at Flint Mill Weir 2006
Measuring authority: EA Grid reference: 44 (SE) 422 473 Catchment area (sq km): 758.9
First year: 1936 Level stn. (m OD): 13.70 Max alt. (m OD): 704
Daily mean gauged discharges (cubic metres per second)
DAY JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1 31.500 5.800 8.290 93.600 6.110 9.790 3.060 3.360 42.300 5.760 15.900 15.300
2 16.100 5.670 7.270 86.100 5.710 7.560 3.120 5.590 68.900 9.930 10.600 13.600
3 12.100 5.480 6.970 58.200 5.510 6.820 3.570 5.430 55.300 12.900 8.550 28.100
4 11.300 5.360 6.420 30.600 5.260 6.640 2.950 4.230 23.800 9.460 7.740 48.800
5 9.160 5.240 6.050 21.700 4.970 6.360 2.820 3.830 14.900 24.900 7.560 159.000
6 8.010 5.170 5.760 25.500 4.900 6.050 2.820 3.210 30.500 41.400 7.140 103.000
7 7.530 5.150 6.390 26.900 5.360 5.750 2.740 3.030 19.500 20.600 6.090 84.800
8 7.260 10.900 13.900 37.600 5.110 5.530 2.680 2.990 10.600 12.900 6.380 86.700
9 6.890 7.530 26.000 34.300 4.870 5.270 2.800 2.950 8.060 9.730 9.260 36.400
10 32.900 6.170 25.700 20.900 4.680 5.020 2.940 2.820 6.820 7.690 7.230 29.900
11 47.100 5.610 15.300 23.200 4.230 4.810 3.070 2.740 6.020 15.300 16.100 132.000
12 17.800 7.100 11.000 21.300 4.180 4.740 2.830 2.760 7.290 24.700 20.600 50.000
13 11.200 12.200 9.380 20.100 4.940 4.550 2.730 2.870 6.810 11.700 20.900 35.700
14 9.480 13.500 20.900 18.500 5.100 4.500 2.680 2.770 21.600 8.470 13.700 119.000
15 9.940 41.600 49.000 12.900 11.300 4.270 2.780 2.710 24.600 7.300 12.800 104.000
16 11.700 17.500 24.900 10.800 17.000 3.930 2.690 2.640 10.600 6.100 24.700 60.600
17 19.400 16.000 17.100 9.570 10.100 3.720 2.630 3.460 7.900 6.200 13.900 37.000
18 12.400 11.500 13.600 8.720 29.100 3.640 2.620 6.660 6.690 6.400 18.700 25.900
19 20.400 8.640 14.900 14.600 24.000 3.620 2.610 12.500 6.320 11.800 28.200 19.700
20 27.900 7.720 17.700 13.600 72.700 3.570 2.660 12.400 7.130 14.200 52.200 16.200
21 20.500 8.880 15.100 10.200 53.700 3.660 2.730 9.730 6.050 9.230 31.400 13.700
22 12.500 8.820 10.700 9.160 101.000 4.640 3.010 9.010 6.280 19.800 20.100 12.000
23 9.760 8.400 9.040 8.590 46.500 5.690 2.760 6.210 5.810 20.400 42.000 10.800
24 8.310 30.300 9.770 7.390 76.200 5.130 2.540 4.810 5.500 15.000 40.100 9.830
25 7.560 15.500 33.100 7.210 33.100 3.960 2.480 4.710 5.970 32.400 101.000 9.030
26 7.450 11.600 64.400 6.790 21.600 4.130 2.460 4.120 5.390 68.200 33.500 8.450
27 6.970 10.500 76.000 6.450 20.100 4.050 2.430 4.270 4.940 30.900 30.100 8.480
28 7.070 9.820 128.000 5.880 15.900 3.590 2.430 16.500 5.130 43.400 29.000 9.640
29 7.570 46.800 5.830 12.100 3.320 2.460 8.780 6.920 32.800 21.900 11.700
30 6.580 66.700 5.810 9.840 3.370 2.530 6.550 5.630 18.900 19.500 73.000
31 6.330 106.000 8.920 2.510 9.020 23.800 56.000
Average 13.890 10.990 28.130 22.070 20.450 4.923 2.746 5.570 14.780 18.780 22.560 46.080
Lowest 6.330 5.150 5.760 5.810 4.180 3.320 2.430 2.640 4.940 5.760 6.090 8.450
Highest 47.100 41.600 128.000 93.600 101.000 9.790 3.570 16.500 68.900 68.200 101.000 159.000
Monthly total
(million cu m) 37.21 26.58 75.35 57.20 54.79 12.76 7.36 14.92 38.30 50.31 58.48 123.40
Runoff (mm) 49 35 99 75 72 17 10 20 50 66 77 163
Rainfall (mm) 44 63 163 72 147 27 44 119 104 127 125 202
Statistics of monthly data for previous record (Oct 1955 to Dec 2005)
Mean Avg. 28.320 24.560 20.970 15.530 10.300 7.373 6.861 10.510 12.180 18.200 23.170 27.500
flows: Low 4.472 2.974 5.740 4.496 2.312 1.545 1.674 0.991 1.419 3.026 6.537 4.832
(year) 1963 1963 1993 1974 1980 1957 1976 1976 1959 1972 1995 1995
High 44.230 71.210 53.940 35.240 26.750 18.530 16.440 41.340 33.520 54.000 66.610 62.090
(year) 1995 2002 1981 1970 1967 1972 1963 1956 1968 1967 2000 1965
Runoff: Avg. 100 79 74 53 36 25 24 37 42 64 79 97
Low 16 9 20 15 8 5 6 4 5 11 22 17
High 156 227 190 120 94 63 58 146 115 191 228 219
Rainfall: Avg. 118 93 90 79 73 76 79 97 98 114 112 127
Low 12 14 24 8 13 18 20 12 8 32 33 41
High 217 285 222 152 181 183 185 226 241 257 242 234
Summary statistics Factors affecting runoff
2006
For 2006 For record As % of $ Reservoir(s) in catchment.
preceding 2006 pre-2006 $ Abstraction for public water supplies.
Mean flow 17.650 17.100 103 $ Flow reduced by industrial and/or
Lowest yearly mean 10.430 1996 agricultural abstractions.
Highest yearly mean 26.320 2000 $ Augmentation from surface water and/or
Lowest monthly mean 2.746 Jul 0.991 Aug 1976 groundwater.
Highest monthly mean 46.080 Dec 71.210 Feb 2002
Lowest daily mean 2.430 27 Jul 0.425 23 Jun 1957
Highest daily mean 159.000 5 Dec 292.900 23 Feb 1991
10% exceedance 42.080 40.740 103
50% exceedance 9.035 9.164 99
95% exceedance 2.727 2.412 113
Annual total (million cu m) 556.60 539.60 103
Annual runoff (mm) 733 711 103
Annual rainfall (mm) 1237 1156 107
{1961-90 rainfall average (mm) 1161}
Station and catchment description
Broad-crested masonry weir 47m wide; c/m cableway originally 1.5km u/s then moved to new ultrasonic station at Tadcaster
in 1990. Insensitive at low flows. Does not drown at high flows, though small amount of bypassing on the right bank.
Level data: 1936-1955. Recalibration (from 1965) completed but flows reprocessed from 1982 only. Pre-1965 data less
reliable. Mill race opened in early 1990s (not rated) so flows not reliable. Regulation effect of headwater reservoirs
evident at low flows. Small net export of water (inc. Bradford supply).
Mixed geology of moderate permeability - mainly Carboniferous Limestone, grits and Coal Measures with over 40%
superficial deposits. Predominantly mixed rural catchment, 60% grassland, with moorland headwaters.
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