027002 Wharfe at Flint Mill Weir 1993
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 6.969 16.500 5.423 4.612 7.218 36.220 3.013 7.102 3.179 14.820 4.388 11.780
2 6.116 14.180 5.262 4.428 6.594 20.230 2.934 6.219 3.134 30.210 4.405 57.210
3 5.722 12.110 5.313 4.811 6.234 14.830 3.071 9.315 3.139 18.800 4.242 27.850
4 6.539 10.780 5.149 8.334 5.706 10.150 3.070 17.460 3.067 16.990 4.113 42.060
5 23.790 9.666 5.285 29.130 5.309 7.858 3.525 65.590 3.032 16.510 4.146 20.910
6 17.540 10.270 10.350 33.250 4.834 6.328 3.545 25.510 3.347 27.180 3.887 16.700
7 11.780 10.160 8.542 14.990 4.492 5.761 3.163 12.590 3.334 37.030 3.630 31.320
8 17.860 9.395 6.924 9.497 4.509 5.353 3.052 11.530 15.480 21.210 3.630 87.870
9 37.720 9.746 6.115 65.210 4.450 5.507 7.943 17.370 24.970 14.570 4.173 81.040
10 59.480 9.502 5.479 35.950 6.748 5.079 5.004 13.810 31.820 11.860 15.150 68.690
11 47.310 9.280 5.278 16.920 5.691 5.016 3.720 31.880 22.360 10.020 7.254 38.390
12 24.800 8.339 5.141 15.530 4.848 4.835 3.315 23.090 11.290 14.760 5.673 29.490
13 60.630 7.475 5.141 15.250 4.483 4.684 3.538 13.370 157.600 14.940 16.370 81.470
14 38.000 7.138 5.739 10.960 83.770 5.714 3.385 9.108 124.100 10.830 31.480 43.200
15 80.680 7.046 5.097 9.300 34.610 5.045 4.141 12.400 92.620 8.642 13.270 86.040
16 42.790 6.995 4.828 8.053 31.550 5.026 8.114 9.870 35.190 7.833 8.755 76.810
17 28.390 6.767 5.750 9.798 55.060 5.527 8.510 7.242 21.800 7.177 7.685 37.530
18 20.440 6.568 7.451 31.800 33.890 8.588 6.034 6.868 15.860 6.591 6.717 80.710
19 42.190 6.938 8.402 33.720 15.850 10.980 27.430 6.206 12.680 6.437 6.601 145.600
20 55.420 7.022 5.937 16.320 13.460 9.085 14.030 6.080 14.670 6.431 5.617 44.430
21 59.830 6.191 5.831 12.610 21.890 6.007 17.320 5.590 14.350 6.094 5.372 26.220
22 47.900 5.771 7.416 10.710 13.340 4.761 7.671 5.315 12.190 5.834 5.271 43.280
23 61.830 5.888 5.524 9.064 9.491 4.554 11.440 4.926 13.770 5.705 5.123 40.960
24 95.220 5.770 5.141 11.010 7.524 3.853 15.340 4.655 9.785 5.517 4.662 32.350
25 42.370 5.610 4.923 41.790 6.309 3.829 9.086 4.607 8.857 5.387 4.766 22.250
26 27.520 6.181 4.559 23.650 5.713 3.726 12.580 4.247 7.713 4.893 5.495 16.710
27 26.550 5.841 4.506 14.150 6.611 3.613 10.470 3.985 6.957 4.786 5.376 13.860
28 60.080 5.314 4.404 10.460 6.604 3.520 12.400 3.796 6.371 5.203 5.273 13.460
29 41.480 4.238 8.343 7.082 3.281 7.525 3.562 6.175 5.136 5.561 57.130
30 25.670 4.250 7.238 7.885 3.120 6.167 3.432 6.757 4.804 8.576 50.390
31 19.780 4.535 74.090 5.143 3.286 4.427 33.670
Average 36.850 8.302 5.740 17.560 16.320 7.403 7.603 11.610 23.190 11.630 7.222 47.080
Lowest 5.722 5.314 4.238 4.428 4.450 3.120 2.934 3.286 3.032 4.427 3.630 11.780
Highest 95.220 16.500 10.350 65.210 83.770 36.220 27.430 65.590 157.600 37.030 31.480 145.600
Monthly total
(million cu m) 98.70 20.08 15.37 45.52 43.71 19.19 20.36 31.10 60.10 31.16 18.72 126.10
Runoff (mm) 130 26 20 60 58 25 27 41 79 41 25 166
Rainfall (mm) 178 21 24 125 134 43 97 93 170 55 53 234
Statistics of monthly data for previous record (Oct 1955 to Dec 1992)
Mean Avg. 27.660 23.580 21.720 15.920 10.540 7.176 7.437 11.180 12.870 17.840 23.440 27.550
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. 98 76 77 54 37 25 26 39 44 63 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. 115 87 93 75 73 76 83 100 100 110 113 124
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
1993
For 1993 For record As % of $ Reservoir(s) in catchment.
preceding 1993 pre-1993 $ Abstraction for public water supplies.
Mean flow 16.810 17.220 98 $ 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 5.740 Mar 0.991 Aug 1976 groundwater.
Highest monthly mean 47.080 Dec 62.090 Dec 1965
Lowest daily mean 2.934 2 Jul 0.425 23 Jun 1957
Highest daily mean 157.600 13 Sep 292.900 23 Feb 1991
10% exceedance 41.610 40.690 102
50% exceedance 7.908 9.497 83
95% exceedance 3.454 2.341 148
Annual total (million cu m) 530.10 543.40 98
Annual runoff (mm) 699 716 98
Annual rainfall (mm) 1227 1149 107
{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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