027002 Wharfe at Flint Mill Weir 1969
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 10.090 15.780 16.570 81.040 15.040 18.520 7.768 3.684 2.982 7.117 6.189 12.300
2 10.860 17.020 15.220 45.450 13.660 16.780 7.776 3.480 2.946 7.176 18.680 18.130
3 10.870 12.600 14.660 31.150 12.980 63.460 7.621 3.780 3.033 17.690 60.500 31.660
4 9.571 11.920 14.720 27.110 12.170 25.800 6.446 4.813 2.943 9.905 64.600 19.890
5 12.850 12.450 14.970 24.400 11.660 17.070 5.558 5.583 2.688 7.615 24.970 13.370
6 10.920 21.910 15.680 23.290 12.590 13.800 5.065 4.448 2.677 6.709 33.710 10.920
7 15.540 19.070 17.210 22.380 13.900 11.240 6.010 3.888 2.476 6.146 20.840 12.850
8 20.090 12.510 16.880 19.950 20.090 9.726 7.491 3.489 2.767 5.821 36.490 17.410
9 18.860 11.930 25.720 18.010 19.790 9.443 7.445 3.396 2.759 5.727 52.110 13.300
10 13.900 11.400 16.330 24.090 14.770 8.872 6.480 3.877 2.258 5.313 44.790 12.290
11 11.110 16.910 12.950 34.310 18.480 8.464 5.923 5.948 10.260 4.825 122.700 14.490
12 23.090 23.360 11.660 50.130 22.930 8.014 5.306 8.042 16.140 4.372 58.680 14.250
13 52.390 15.350 12.360 32.050 16.250 7.833 4.615 5.676 10.360 4.392 31.140 12.220
14 32.700 12.770 16.660 21.150 13.580 7.646 4.536 4.966 8.515 4.479 22.890 46.250
15 24.560 10.440 27.530 26.430 19.860 7.476 4.680 4.895 6.568 4.293 25.260 38.850
16 18.950 9.064 34.640 22.120 29.400 8.240 4.547 5.626 6.039 4.174 21.890 24.170
17 15.800 9.839 23.550 17.220 22.570 8.255 4.278 4.751 5.756 3.959 21.120 17.440
18 21.170 9.095 20.150 14.180 16.170 15.250 4.270 4.041 7.720 3.650 17.990 13.920
19 25.340 9.002 18.710 12.760 14.600 14.200 4.199 3.891 8.560 3.594 24.040 12.110
20 61.520 9.112 22.550 11.530 12.480 15.550 3.381 3.933 6.248 3.613 22.620 11.250
21 113.700 8.965 24.490 15.420 10.820 17.590 3.579 9.118 11.370 3.877 27.830 73.910
22 50.330 12.320 22.550 38.920 9.718 11.330 3.930 6.763 21.640 3.877 26.040 78.700
23 31.700 23.540 18.030 30.650 9.072 18.770 3.928 5.343 10.320 3.775 21.770 31.190
24 23.900 37.160 16.160 24.920 9.488 31.160 3.970 4.794 8.051 11.230 16.260 27.370
25 19.360 25.000 15.950 42.920 13.040 16.630 3.913 4.409 7.366 10.180 13.280 26.530
26 16.590 22.550 16.320 50.200 14.250 11.440 3.647 4.205 7.516 8.951 11.640 18.260
27 14.650 18.270 15.120 43.510 26.740 9.718 3.367 3.993 10.670 7.275 11.390 14.630
28 13.190 17.270 15.650 26.820 32.500 8.597 4.366 3.828 8.368 5.974 24.560 12.750
29 12.130 28.160 19.920 20.470 7.612 4.873 3.571 11.890 5.744 14.070 11.670
30 11.650 76.870 17.570 20.960 7.689 4.907 3.328 7.977 5.892 11.030 10.940
31 14.500 189.300 22.290 4.349 3.254 5.133 10.100
Average 23.930 15.590 26.040 28.990 16.850 14.540 5.104 4.671 7.295 6.209 30.300 22.040
Lowest 9.571 8.965 11.660 11.530 9.072 7.476 3.367 3.254 2.258 3.594 6.189 10.100
Highest 113.700 37.160 189.300 81.040 32.500 63.460 7.776 9.118 21.640 17.690 122.700 78.700
Monthly total
(million cu m) 64.10 37.72 69.75 75.13 45.13 37.69 13.67 12.51 18.91 16.63 78.54 59.02
Runoff (mm) 84 50 92 99 59 50 18 16 25 22 104 78
Rainfall (mm) 103 92 123 100 109 94 54 82 78 38 173 90
Statistics of monthly data for previous record (Oct 1955 to Dec 1968)
Mean Avg. 25.800 23.250 19.040 15.060 12.510 6.799 9.701 14.600 15.770 18.440 21.700 28.180
flows: Low 4.472 2.974 6.741 5.197 3.911 1.545 3.601 1.795 1.419 6.597 6.876 10.230
(year) 1963 1963 1961 1957 1960 1957 1959 1959 1959 1955 1958 1963
High 39.260 54.590 36.400 29.330 26.750 14.450 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1961 1966 1963 1966 1967 1958 1963 1956 1968 1967 1963 1965
Runoff: Avg. 91 75 67 51 44 23 34 52 54 65 74 99
Low 16 9 24 18 14 5 13 6 5 23 23 36
High 139 174 128 100 94 49 58 146 115 191 174 219
Rainfall: Avg. 101 83 74 75 80 74 95 112 108 107 99 124
Low 41 20 28 10 25 33 35 18 8 46 33 41
High 165 194 148 130 181 140 185 226 241 225 211 224
Summary statistics Factors affecting runoff
1969
For 1969 For record As % of $ Reservoir(s) in catchment.
preceding 1969 pre-1969 $ Abstraction for public water supplies.
Mean flow 16.770 17.560 96 $ 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 4.671 Aug 1.419 Sep 1959 groundwater.
Highest monthly mean 30.300 Nov 62.090 Dec 1965
Lowest daily mean 2.258 10 Sep 0.425 23 Jun 1957
Highest daily mean 189.300 31 Mar 233.600 4 Dec 1960
10% exceedance 30.860 40.940 75
50% exceedance 12.690 9.534 133
95% exceedance 3.555 2.424 147
Annual total (million cu m) 528.90 554.20 95
Annual runoff (mm) 697 730 95
Annual rainfall (mm) 1136 1132 100
{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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