027002 Wharfe at Flint Mill Weir 1988
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 92.880 106.200 6.922 12.960 4.789 4.100 2.785 14.990 39.910 9.707 10.040 42.250
2 165.000 128.600 6.518 17.090 7.240 3.686 2.765 11.870 40.180 7.650 8.875 24.070
3 116.200 80.210 12.130 13.370 15.620 3.680 2.881 9.013 41.460 6.352 7.903 26.640
4 86.880 74.910 11.120 12.160 16.810 3.521 4.393 7.219 40.230 6.571 7.460 94.610
5 54.900 47.150 7.934 10.520 12.860 3.515 3.818 6.955 23.270 7.498 7.254 43.450
6 69.470 34.790 7.577 9.319 8.301 3.378 4.114 6.161 14.770 31.460 6.915 23.900
7 36.910 27.360 10.480 8.587 6.615 3.316 9.491 5.826 11.410 70.640 6.606 16.950
8 25.040 29.660 7.658 8.337 5.955 5.177 10.640 5.187 9.459 36.460 6.619 14.580
9 29.700 66.690 8.747 8.002 5.375 3.375 9.894 4.675 7.956 31.430 30.480 18.450
10 27.250 112.900 13.860 7.334 4.965 3.187 11.470 4.325 7.024 22.510 19.070 16.140
11 28.230 49.000 12.540 6.949 4.501 3.071 9.811 4.147 7.391 15.970 20.700 12.440
12 29.110 30.810 13.600 6.579 4.822 2.983 5.928 20.830 7.418 22.700 11.910 10.980
13 30.880 56.570 15.840 6.113 4.833 2.796 26.350 19.840 7.132 24.650 11.290 9.648
14 19.750 74.800 17.610 5.723 4.532 2.643 15.170 56.570 5.966 15.970 9.592 8.803
15 15.370 43.520 65.520 5.471 4.223 2.559 10.840 23.970 5.275 12.170 8.276 8.066
16 13.660 36.230 48.190 5.403 3.848 2.734 7.651 12.370 4.887 10.290 7.474 7.667
17 13.990 23.230 20.290 5.466 3.784 2.696 12.100 8.441 4.604 8.996 7.340 7.364
18 36.230 21.070 15.050 5.870 3.926 2.689 8.947 32.090 4.548 9.135 16.260 7.483
19 34.780 20.840 35.420 6.709 4.016 2.653 6.695 50.180 4.285 18.500 11.830 62.890
20 22.400 16.340 34.850 6.214 3.750 2.649 5.500 88.850 4.259 39.550 10.220 22.520
21 19.000 13.550 24.330 5.367 3.387 2.630 16.530 32.810 4.368 25.480 8.679 16.130
22 16.420 11.990 23.950 5.089 3.319 2.621 12.720 17.900 4.329 15.410 7.638 19.500
23 15.660 10.970 47.340 5.147 3.304 2.800 26.900 12.600 7.260 12.250 7.576 130.700
24 93.810 9.712 40.690 5.102 3.494 2.520 17.280 10.430 27.440 13.990 7.733 57.870
25 46.370 8.752 26.850 4.862 3.593 2.477 14.350 9.434 19.310 15.770 9.488 28.500
26 28.150 8.086 19.200 4.856 4.789 3.700 11.140 10.220 54.290 63.580 9.930 39.050
27 20.160 8.022 21.700 4.814 6.035 2.805 7.989 34.180 16.080 51.470 8.155 50.800
28 16.560 8.257 24.800 5.250 4.985 2.599 39.070 17.570 30.740 31.230 16.900 23.070
29 19.850 7.704 23.870 4.548 4.004 2.681 52.320 45.910 28.020 18.670 16.960 16.820
30 27.860 16.950 4.188 4.022 3.161 40.940 30.970 14.370 13.950 52.630 13.410
31 56.270 15.620 4.398 30.880 34.890 11.540 10.870
Average 42.220 40.270 21.200 7.247 5.680 3.080 14.240 20.980 16.590 21.990 12.390 28.570
Lowest 13.660 7.704 6.518 4.188 3.304 2.477 2.765 4.147 4.259 6.352 6.606 7.364
Highest 165.000 128.600 65.520 17.090 16.810 5.177 52.320 88.850 54.290 70.640 52.630 130.700
Monthly total
(million cu m) 113.10 100.90 56.78 18.78 15.21 7.98 38.13 56.20 43.00 58.89 32.12 76.52
Runoff (mm) 149 133 75 25 20 11 50 74 57 78 42 101
Rainfall (mm) 187 130 119 36 61 32 185 154 93 127 69 113
Statistics of monthly data for previous record (Oct 1955 to Dec 1987)
Mean Avg. 27.590 22.500 21.350 16.210 11.330 7.627 7.531 11.650 13.640 18.240 23.900 27.690
flows: Low 4.472 2.974 6.741 4.496 2.312 1.545 1.674 0.991 1.419 3.026 6.876 10.230
(year) 1963 1963 1961 1974 1980 1957 1976 1976 1959 1972 1958 1963
High 44.000 54.590 53.940 35.240 26.750 18.530 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1984 1966 1981 1970 1967 1972 1963 1956 1968 1967 1963 1965
Runoff: Avg. 97 72 75 55 40 26 27 41 47 64 82 98
Low 16 9 24 15 8 5 6 4 5 11 23 36
High 155 174 190 120 94 63 58 146 115 191 174 219
Rainfall: Avg. 113 79 90 76 78 76 83 100 104 108 113 124
Low 41 14 28 8 13 18 20 18 8 32 33 41
High 217 194 222 147 181 183 185 226 241 225 211 233
Summary statistics Factors affecting runoff
1988
For 1988 For record As % of $ Reservoir(s) in catchment.
preceding 1988 pre-1988 $ Abstraction for public water supplies.
Mean flow 19.530 17.420 112 $ Flow reduced by industrial and/or
Lowest yearly mean 11.420 1975 agricultural abstractions.
Highest yearly mean 23.300 1966 $ Augmentation from surface water and/or
Lowest monthly mean 3.080 Jun 0.991 Aug 1976 groundwater.
Highest monthly mean 42.220 Jan 62.090 Dec 1965
Lowest daily mean 2.477 25 Jun 0.425 23 Jun 1957
Highest daily mean 165.000 2 Jan 288.400 3 Jan 1982
10% exceedance 45.990 41.390 111
50% exceedance 11.330 9.708 117
95% exceedance 2.863 2.301 124
Annual total (million cu m) 617.60 549.70 112
Annual runoff (mm) 814 724 112
Annual rainfall (mm) 1306 1144 114
{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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