027002 Wharfe at Flint Mill Weir 1973
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 6.472 11.730 37.830 5.495 7.335 5.461 2.631 4.907 4.061 12.720 6.435 5.388
2 6.800 10.270 27.730 18.390 7.100 5.269 2.728 4.584 6.494 9.755 6.217 5.814
3 9.921 9.160 64.290 11.670 6.401 22.260 2.521 4.556 5.461 8.099 5.996 6.761
4 9.514 8.705 48.490 79.710 16.350 11.580 2.632 4.641 27.100 7.256 5.705 8.069
5 8.085 8.340 29.320 54.240 18.430 7.527 2.394 9.537 12.090 6.681 7.686 8.421
6 7.083 9.106 24.210 32.130 11.680 6.025 2.493 59.940 7.601 6.325 8.379 8.002
7 6.475 13.730 21.310 21.970 20.290 5.365 4.250 44.950 5.959 5.730 6.602 11.890
8 6.121 12.340 19.520 16.220 13.730 4.844 5.399 26.150 5.170 5.410 6.070 31.410
9 5.730 15.410 14.960 13.150 9.899 4.465 4.131 14.810 4.717 9.514 51.990 15.090
10 5.645 14.920 12.400 11.880 23.630 4.230 3.240 14.530 4.363 47.860 62.480 10.930
11 5.648 11.790 10.870 10.540 18.300 3.998 2.979 15.230 4.069 29.310 28.640 33.120
12 5.518 47.090 9.788 9.508 11.650 3.862 2.753 11.670 3.848 15.030 40.450 40.420
13 5.391 26.870 8.956 8.484 20.480 3.664 3.081 8.506 3.639 11.550 43.510 46.500
14 5.425 17.560 8.410 7.875 15.730 3.534 9.559 7.131 3.537 10.650 30.560 25.240
15 10.240 13.300 7.932 7.522 10.140 3.364 22.590 6.237 3.480 11.410 22.750 14.940
16 14.800 13.220 7.519 6.944 8.410 3.294 107.900 5.742 3.480 12.030 16.960 45.710
17 10.180 11.700 7.075 6.477 7.341 3.113 66.550 5.351 3.540 9.998 12.870 24.360
18 8.079 11.600 6.625 6.087 6.998 3.172 28.080 4.963 4.024 9.087 11.090 15.860
19 7.205 40.290 6.313 5.923 6.548 3.305 19.100 5.130 10.460 46.930 11.610 13.270
20 7.275 36.140 6.112 5.668 7.533 3.840 16.050 5.795 8.908 41.270 10.260 52.160
21 11.170 22.950 5.920 5.487 7.089 3.840 21.650 7.824 5.906 35.110 8.872 47.870
22 19.550 19.150 5.716 5.710 9.135 3.633 33.040 6.582 5.422 19.010 8.373 33.270
23 27.440 23.440 5.558 13.760 9.138 3.299 18.230 5.521 15.050 16.400 8.011 25.610
24 61.040 17.390 5.433 39.820 8.023 3.067 11.630 4.881 10.460 12.530 7.556 17.780
25 33.300 14.440 5.433 14.610 7.083 4.250 9.169 4.508 7.482 10.350 7.776 15.250
26 46.880 12.850 5.207 9.766 6.288 4.578 7.717 4.236 6.540 9.146 7.216 15.240
27 34.730 11.590 5.150 8.136 5.733 4.174 6.828 4.066 10.490 8.529 6.525 14.120
28 19.180 11.760 5.045 7.366 5.317 3.761 6.092 3.933 48.420 7.870 6.092 16.740
29 15.280 4.986 6.803 4.975 3.446 5.693 3.676 29.400 7.414 6.112 32.960
30 15.750 4.870 6.939 5.079 3.022 6.276 3.851 20.860 6.913 5.365 21.480
31 14.670 4.910 5.617 5.705 4.324 6.599 15.610
Average 14.540 17.030 14.130 15.280 10.370 4.975 14.290 10.250 9.734 14.730 15.610 21.910
Lowest 5.391 8.340 4.870 5.487 4.975 3.022 2.394 3.676 3.480 5.410 5.365 5.388
Highest 61.040 47.090 64.290 79.710 23.630 22.260 107.900 59.940 48.420 47.860 62.480 52.160
Monthly total
(million cu m) 38.93 41.20 37.83 39.60 27.77 12.89 38.28 27.45 25.23 39.44 40.45 58.69
Runoff (mm) 51 54 50 52 37 17 50 36 33 52 53 77
Rainfall (mm) 58 73 36 96 82 40 152 93 105 76 65 96
Statistics of monthly data for previous record (Oct 1955 to Dec 1972)
Mean Avg. 25.430 23.330 18.760 17.300 12.350 7.809 9.068 13.450 13.880 17.090 23.050 26.300
flows: Low 4.472 2.974 6.741 5.197 3.911 1.545 3.601 1.795 1.419 3.026 6.876 10.230
(year) 1963 1963 1961 1957 1960 1957 1959 1959 1959 1972 1958 1963
High 39.260 54.590 36.400 35.240 26.750 18.530 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1961 1966 1963 1970 1967 1972 1963 1956 1968 1967 1963 1965
Runoff: Avg. 90 75 66 59 44 27 32 47 47 60 79 93
Low 16 9 24 18 14 5 13 6 5 11 23 36
High 139 174 128 120 94 63 58 146 115 191 174 219
Rainfall: Avg. 103 85 78 80 80 77 92 102 97 101 110 114
Low 41 20 28 10 13 33 35 18 8 34 33 41
High 165 194 148 147 181 140 185 226 241 225 211 224
Summary statistics Factors affecting runoff
1973
For 1973 For record As % of $ Reservoir(s) in catchment.
preceding 1973 pre-1973 $ Abstraction for public water supplies.
Mean flow 13.560 17.290 78 $ Flow reduced by industrial and/or
Lowest yearly mean 12.390 1964 agricultural abstractions.
Highest yearly mean 23.300 1966 $ Augmentation from surface water and/or
Lowest monthly mean 4.975 Jun 1.419 Sep 1959 groundwater.
Highest monthly mean 21.910 Dec 62.090 Dec 1965
Lowest daily mean 2.394 5 Jul 0.425 23 Jun 1957
Highest daily mean 107.900 16 Jul 233.600 4 Dec 1960
10% exceedance 31.430 39.860 79
50% exceedance 8.376 9.671 87
95% exceedance 3.414 2.584 132
Annual total (million cu m) 427.60 545.70 78
Annual runoff (mm) 563 719 78
Annual rainfall (mm) 972 1119 87
{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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