027002 Wharfe at Flint Mill Weir 1982
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 22.920 13.060 19.460 6.409 3.165 4.507 10.410 2.508 8.982 9.185 13.600 11.790
2 64.130 11.950 12.980 6.050 3.293 5.324 8.167 2.588 6.918 37.900 14.240 10.880
3 288.400 9.945 56.600 5.700 23.420 3.797 6.940 2.530 5.682 15.730 14.480 9.816
4 188.500 8.643 25.880 5.528 8.948 2.945 5.964 3.233 5.111 11.190 24.550 9.404
5 133.200 19.740 16.340 5.540 6.450 2.642 5.487 3.328 5.098 14.890 22.370 28.790
6 54.150 24.530 19.060 5.305 5.080 10.750 5.028 2.615 4.907 45.190 35.200 15.490
7 29.730 22.380 28.020 5.816 4.013 10.130 4.328 2.379 6.816 18.410 16.620 33.350
8 21.010 15.000 15.160 8.400 3.742 4.543 3.884 2.217 8.355 16.750 16.510 80.050
9 16.480 37.900 13.930 6.942 3.617 3.126 4.104 2.064 5.552 11.550 29.820 51.620
10 13.300 19.530 61.100 5.512 3.576 3.061 3.884 2.024 4.420 9.487 19.670 45.370
11 11.950 15.040 29.560 4.973 3.381 3.239 3.570 1.947 3.852 8.483 23.680 24.850
12 9.787 15.410 50.420 4.594 3.257 4.257 4.485 1.937 3.611 7.649 63.710 18.270
13 8.589 12.950 27.100 4.377 3.083 3.876 3.188 2.046 3.319 14.030 32.400 14.670
14 7.175 11.670 70.670 4.326 3.060 3.041 2.936 2.582 3.156 12.010 32.400 13.250
15 7.444 10.140 124.300 4.195 2.973 2.852 4.683 2.904 3.005 8.621 23.680 101.200
16 8.866 8.407 43.280 4.090 2.966 3.104 7.106 4.459 2.820 7.478 70.940 52.710
17 9.528 7.562 34.180 3.964 2.881 3.058 5.363 5.691 2.793 20.520 38.530 25.710
18 13.200 7.266 27.690 3.854 2.811 4.180 3.885 81.150 2.680 12.170 54.390 17.950
19 12.990 6.799 21.900 3.812 2.850 6.313 3.427 30.600 2.861 9.154 48.250 80.950
20 14.490 6.499 23.670 3.731 2.680 5.054 3.235 26.720 3.929 46.000 41.120 102.700
21 18.380 6.041 21.650 3.708 2.720 7.395 3.100 16.980 11.820 23.590 87.470 84.510
22 23.810 5.533 19.420 3.626 2.870 52.910 3.053 31.330 8.136 13.510 64.920 34.120
23 26.060 5.308 14.440 3.540 3.301 56.260 2.999 23.410 7.034 10.190 67.730 21.750
24 16.900 5.053 11.850 3.516 5.200 21.730 2.911 27.320 15.410 8.448 59.800 25.730
25 14.220 5.060 10.320 3.407 3.675 44.580 2.823 26.500 27.810 13.930 60.560 26.870
26 43.400 5.591 9.117 3.343 8.817 69.970 2.716 16.700 10.740 9.708 35.560 62.550
27 22.090 11.240 8.319 3.304 5.552 33.770 2.604 14.390 19.800 10.070 24.770 50.980
28 15.150 8.669 7.723 3.216 3.806 37.450 2.564 17.060 29.210 8.229 19.630 28.610
29 14.650 7.186 3.011 4.746 27.770 2.575 9.181 28.510 7.054 15.900 20.640
30 17.180 6.960 3.122 3.401 15.260 2.451 17.320 12.890 6.420 13.390 17.450
31 14.630 6.601 2.908 2.452 14.140 6.004 24.990
Average 37.490 12.030 27.250 4.564 4.588 15.230 4.204 12.900 8.841 14.630 36.200 37.000
Lowest 7.175 5.053 6.601 3.011 2.680 2.642 2.451 1.937 2.680 6.004 13.390 9.404
Highest 288.400 37.900 124.300 8.400 23.420 69.970 10.410 81.150 29.210 46.000 87.470 102.700
Monthly total
(million cu m) 100.40 29.11 73.00 11.83 12.29 39.48 11.26 34.55 22.92 39.19 93.82 99.10
Runoff (mm) 132 38 96 16 16 52 15 46 30 52 124 131
Rainfall (mm) 99 46 130 23 51 183 22 139 78 81 180 153
Statistics of monthly data for previous record (Oct 1955 to Dec 1981)
Mean Avg. 26.520 23.550 21.360 15.640 11.330 7.199 8.060 11.760 14.030 17.970 23.600 26.540
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 39.260 54.590 53.940 35.240 26.750 18.530 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1961 1966 1981 1970 1967 1972 1963 1956 1968 1967 1963 1965
Runoff: Avg. 94 76 75 53 40 25 28 41 48 63 81 94
Low 16 9 24 15 8 5 6 4 5 11 23 36
High 139 174 190 120 94 63 58 146 115 191 174 219
Rainfall: Avg. 108 86 87 74 77 74 88 98 106 105 110 117
Low 41 20 28 8 13 18 35 18 8 32 33 41
High 165 194 222 147 181 177 185 226 241 225 211 224
Summary statistics Factors affecting runoff
1982
For 1982 For record As % of $ Reservoir(s) in catchment.
preceding 1982 pre-1982 $ Abstraction for public water supplies.
Mean flow 17.980 17.270 104 $ 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 4.204 Jul 0.991 Aug 1976 groundwater.
Highest monthly mean 37.490 Jan 62.090 Dec 1965
Lowest daily mean 1.937 12 Aug 0.425 23 Jun 1957
Highest daily mean 288.400 3 Jan 233.600 4 Dec 1960
10% exceedance 43.870 40.820 107
50% exceedance 9.194 9.702 95
95% exceedance 2.667 2.233 119
Annual total (million cu m) 567.00 545.00 104
Annual runoff (mm) 747 718 104
Annual rainfall (mm) 1185 1130 105
{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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