027002 Wharfe at Flint Mill Weir 1980
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 15.410 36.520 10.060 21.480 2.816 2.495 39.890 7.923 8.484 7.049 18.160 15.810
2 12.270 25.480 9.782 15.620 2.670 2.268 17.730 7.636 6.852 7.501 14.720 23.500
3 27.950 22.590 8.193 13.460 2.634 2.217 12.840 7.065 5.923 6.220 12.470 15.930
4 94.920 21.250 7.719 11.150 2.587 2.230 9.135 11.580 5.367 6.182 11.170 12.550
5 49.070 53.850 7.545 9.858 2.516 2.635 7.868 29.410 5.872 6.945 10.270 11.520
6 33.880 67.280 7.945 8.967 2.500 15.210 6.679 20.260 6.309 60.030 10.100 10.860
7 23.200 45.930 14.410 8.339 2.500 5.441 5.696 52.630 5.288 67.920 10.220 9.050
8 18.400 98.660 14.620 7.796 2.449 4.434 4.869 49.460 4.619 48.490 11.480 8.147
9 14.550 142.900 12.300 7.271 2.339 3.863 3.982 18.350 4.232 24.950 9.985 7.872
10 12.090 82.740 12.340 6.810 2.370 2.973 3.521 11.620 4.352 16.040 8.665 19.490
11 10.890 50.330 14.450 6.527 2.325 3.521 3.461 15.780 19.870 14.140 8.068 91.270
12 10.010 34.600 56.700 6.146 2.253 3.549 3.236 29.200 43.920 10.600 7.556 29.500
13 9.358 26.970 30.460 5.865 2.186 3.745 3.083 18.720 26.240 8.837 6.983 56.900
14 9.541 22.390 17.770 5.527 2.109 10.920 3.659 17.830 61.490 7.765 65.610 45.940
15 9.887 27.780 13.530 5.397 2.082 16.620 3.228 46.870 37.520 6.983 48.790 29.760
16 9.586 20.680 11.240 5.157 2.055 12.340 2.868 21.730 24.500 19.330 47.580 17.580
17 8.679 16.830 18.560 5.071 2.027 22.470 2.588 14.770 27.680 22.840 86.550 56.670
18 8.121 15.640 86.800 4.902 1.998 10.550 4.832 12.870 19.020 12.600 61.980 33.030
19 7.575 12.910 38.630 4.767 2.020 6.400 9.997 12.030 18.990 16.360 62.660 25.180
20 7.257 11.220 23.190 4.484 2.322 9.069 13.790 30.870 19.480 13.560 43.970 25.470
21 11.940 14.780 17.980 4.340 2.148 17.300 6.904 34.850 16.570 14.450 39.120 20.020
22 46.750 68.510 14.570 4.177 2.191 23.040 4.514 15.210 13.940 33.470 105.600 49.720
23 76.440 44.290 12.890 3.586 2.045 14.170 3.309 10.080 13.200 97.140 35.340 70.440
24 43.240 26.700 18.820 3.366 2.012 10.300 2.904 8.021 17.030 55.600 52.330 37.460
25 30.020 20.180 58.390 3.169 2.076 11.130 2.840 6.904 14.190 35.110 59.620 44.820
26 20.860 16.830 44.480 3.052 2.022 9.562 2.680 6.197 10.250 29.520 44.710 31.320
27 15.190 13.650 41.900 3.006 2.685 9.076 2.825 5.749 8.512 194.800 41.230 19.900
28 15.530 11.730 42.810 2.974 2.580 7.533 2.887 5.313 8.445 97.140 27.450 25.670
29 21.400 10.630 37.160 2.897 2.354 9.100 2.572 10.390 7.305 61.580 19.240 34.700
30 81.900 22.940 2.857 2.421 32.300 34.130 25.300 7.412 33.010 15.370 37.410
31 78.780 18.540 2.392 16.260 14.520 23.140 42.460
Average 26.930 36.680 24.090 6.601 2.312 9.549 7.896 18.680 15.760 34.170 33.230 30.970
Lowest 7.257 10.630 7.545 2.857 1.998 2.217 2.572 5.313 4.232 6.182 6.983 7.872
Highest 94.920 142.900 86.800 21.480 2.816 32.300 39.890 52.630 61.490 194.800 105.600 91.270
Monthly total
(million cu m) 72.12 91.92 64.52 17.11 6.19 24.75 21.15 50.04 40.86 91.52 86.14 82.94
Runoff (mm) 95 121 85 23 8 33 28 66 54 121 114 109
Rainfall (mm) 124 118 128 8 31 177 69 157 97 203 138 110
Statistics of monthly data for previous record (Oct 1955 to Dec 1979)
Mean Avg. 26.330 23.170 19.890 16.140 11.730 6.940 8.234 11.800 13.880 16.760 23.050 26.950
flows: Low 4.472 2.974 6.741 4.496 2.794 1.545 1.674 0.991 1.419 3.026 6.876 10.230
(year) 1963 1963 1961 1974 1974 1957 1976 1976 1959 1972 1958 1963
High 39.260 54.590 53.890 35.240 26.750 18.530 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1961 1966 1979 1970 1967 1972 1963 1956 1968 1967 1963 1965
Runoff: Avg. 93 74 70 55 41 24 29 42 47 59 79 95
Low 16 9 24 15 10 5 6 4 5 11 23 36
High 139 174 190 120 94 63 58 146 115 191 174 219
Rainfall: Avg. 108 84 80 76 78 70 90 97 104 98 109 119
Low 41 20 28 10 13 18 35 18 8 32 33 41
High 165 194 170 147 181 140 185 226 241 225 211 224
Summary statistics Factors affecting runoff
1980
For 1980 For record As % of $ Reservoir(s) in catchment.
preceding 1980 pre-1980 $ Abstraction for public water supplies.
Mean flow 20.530 17.050 120 $ 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 2.312 May 0.991 Aug 1976 groundwater.
Highest monthly mean 36.680 Feb 62.090 Dec 1965
Lowest daily mean 1.998 18 May 0.425 23 Jun 1957
Highest daily mean 194.800 27 Oct 233.600 4 Dec 1960
10% exceedance 49.020 40.160 122
50% exceedance 12.370 9.555 129
95% exceedance 2.322 2.247 103
Annual total (million cu m) 649.20 538.00 121
Annual runoff (mm) 855 709 121
Annual rainfall (mm) 1360 1113 122
{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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