027002 Wharfe at Flint Mill Weir 1992
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 8.158 3.299 18.960 32.210 39.650 3.719 2.575 2.000 14.870 6.389 14.780 86.770
2 8.265 3.140 19.280 19.130 16.790 3.658 2.562 1.932 20.760 11.660 35.140 171.100
3 18.700 12.810 36.970 15.440 11.260 4.650 3.129 1.968 18.320 35.180 26.090 71.320
4 37.160 31.060 19.530 13.940 8.841 4.588 4.366 1.979 9.257 18.150 15.700 43.210
5 142.700 17.020 12.030 11.520 7.565 4.492 4.673 1.941 5.963 10.350 13.530 31.960
6 95.110 9.736 9.720 11.030 6.641 4.275 3.416 2.012 4.948 7.403 18.990 35.940
7 37.120 7.773 9.022 13.060 6.494 3.999 2.784 2.099 21.800 6.655 31.100 47.060
8 27.800 6.117 11.270 18.770 8.576 3.663 2.778 3.546 14.160 5.659 16.570 25.520
9 28.280 5.457 8.525 12.050 11.930 3.359 2.756 9.093 13.450 5.081 27.830 18.650
10 19.050 6.521 17.140 9.488 11.790 3.212 2.605 6.690 9.332 4.583 39.390 15.430
11 14.040 10.030 39.160 7.986 8.219 3.001 2.600 3.869 6.264 4.264 45.400 22.910
12 12.310 8.350 114.500 7.067 31.690 2.812 2.825 5.970 18.220 4.036 32.600 26.010
13 11.340 12.430 83.370 13.620 14.490 2.721 3.201 9.824 39.660 3.798 24.210 19.650
14 9.932 12.220 35.410 37.950 8.725 2.793 3.005 5.027 17.740 3.818 16.620 30.240
15 8.788 20.860 25.150 46.640 6.804 2.647 2.663 3.655 12.400 4.516 19.480 26.740
16 8.060 12.620 21.630 24.150 5.613 2.550 2.329 3.031 9.168 4.410 22.510 19.730
17 7.389 9.178 16.310 18.840 5.203 2.442 2.332 3.401 6.596 3.896 19.650 16.600
18 6.459 8.562 16.260 49.430 4.748 2.369 2.217 2.920 5.305 3.686 15.360 105.700
19 5.950 8.941 18.120 31.660 4.334 2.350 4.310 2.862 4.894 3.501 20.550 42.450
20 5.901 11.230 26.630 16.970 4.319 2.334 6.061 2.631 5.176 3.546 21.370 21.520
21 5.517 22.700 64.020 12.560 4.204 2.347 4.008 2.375 6.872 3.416 37.350 15.750
22 5.150 61.150 35.310 11.080 4.075 2.317 3.153 2.617 33.970 3.440 57.310 12.940
23 4.649 46.410 22.070 11.110 3.833 2.304 3.046 2.599 15.700 3.572 49.490 10.920
24 4.464 21.080 15.460 9.774 4.121 2.362 2.572 3.686 8.759 4.148 28.710 9.582
25 4.158 13.980 12.480 11.540 3.748 2.257 2.348 3.125 7.239 10.260 31.200 9.280
26 3.824 11.160 11.530 15.270 3.486 2.209 2.258 4.989 6.781 15.580 33.390 8.969
27 3.665 9.605 9.448 18.510 3.330 2.201 2.194 25.110 5.475 57.460 26.530 8.522
28 3.593 12.950 7.893 17.490 3.503 2.197 2.241 23.520 5.197 48.260 31.280 8.177
29 3.444 9.146 8.264 12.030 3.968 2.425 2.163 10.650 4.856 29.170 18.880 7.788
30 3.379 20.220 32.120 3.938 2.377 2.101 35.960 5.395 16.240 59.240 7.136
31 3.342 75.140 4.331 2.020 39.160 10.850 6.720
Average 17.990 14.670 27.120 18.750 8.588 2.954 2.945 7.427 11.950 11.390 28.340 31.750
Lowest 3.342 3.140 7.893 7.067 3.330 2.197 2.020 1.932 4.856 3.416 13.530 6.720
Highest 142.700 61.150 114.500 49.430 39.650 4.650 6.061 39.160 39.660 57.460 59.240 171.100
Monthly total
(million cu m) 48.19 36.77 72.65 48.59 23.00 7.66 7.89 19.89 30.98 30.50 73.46 85.04
Runoff (mm) 63 48 96 64 30 10 10 26 41 40 97 112
Rainfall (mm) 83 89 149 105 51 26 74 140 108 92 165 114
Statistics of monthly data for previous record (Oct 1955 to Dec 1991)
Mean Avg. 27.930 23.820 21.570 15.840 10.600 7.293 7.561 11.280 12.900 18.010 23.310 27.440
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. 99 77 76 54 37 25 27 40 44 64 80 97
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. 116 86 92 75 73 77 83 98 99 110 111 125
Low 41 14 28 8 13 18 20 18 8 32 33 41
High 217 201 222 147 181 183 185 226 241 225 211 233
Summary statistics Factors affecting runoff
1992
For 1992 For record As % of $ Reservoir(s) in catchment.
preceding 1992 pre-1992 $ Abstraction for public water supplies.
Mean flow 15.320 17.270 89 $ 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 2.945 Jul 0.991 Aug 1976 groundwater.
Highest monthly mean 31.750 Dec 62.090 Dec 1965
Lowest daily mean 1.932 2 Aug 0.425 23 Jun 1957
Highest daily mean 171.100 2 Dec 292.900 23 Feb 1991
10% exceedance 35.590 40.980 87
50% exceedance 8.972 9.510 94
95% exceedance 2.275 2.349 97
Annual total (million cu m) 484.50 545.00 89
Annual runoff (mm) 638 718 89
Annual rainfall (mm) 1196 1145 104
{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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