027002 Wharfe at Flint Mill Weir 1957
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 30.870 43.890 12.740 8.382 2.775 1.359 2.619 3.087 5.437 7.929 72.770 5.125
2 25.880 36.250 11.160 7.362 3.115 1.359 1.509 2.302 5.862 7.277 67.960 5.380
3 31.430 22.310 9.939 7.108 2.917 2.775 1.977 1.523 4.474 6.570 42.480 4.248
4 33.700 30.020 9.769 6.966 2.280 1.665 4.417 2.161 4.616 6.145 30.020 4.531
5 136.200 33.410 8.580 6.541 1.996 2.124 5.522 1.996 4.446 5.409 82.120 4.672
6 68.530 33.130 9.005 5.578 4.021 2.124 2.444 2.444 5.578 5.437 45.310 4.531
7 31.720 62.010 13.790 5.720 1.671 1.685 1.996 2.464 6.286 6.145 24.040 10.960
8 24.040 79.570 12.660 6.824 1.821 1.203 2.775 2.464 7.646 4.474 17.610 122.600
9 26.420 37.660 25.570 5.550 1.821 2.585 3.087 3.398 6.428 4.304 14.440 52.950
10 20.840 23.730 40.490 5.380 1.665 2.888 2.302 20.160 8.835 4.333 13.170 21.120
11 13.540 20.420 39.640 5.182 1.826 2.302 2.302 19.260 12.490 4.049 12.090 30.870
12 19.260 21.040 20.080 4.899 2.302 3.087 6.598 23.190 24.690 3.681 20.280 38.230
13 16.710 28.320 14.220 3.426 2.138 1.982 41.910 10.730 19.340 3.426 16.370 27.470
14 12.180 34.550 12.230 4.163 1.982 1.509 23.930 7.277 13.280 4.531 12.350 17.950
15 10.590 26.050 48.140 5.833 18.490 1.515 16.930 26.990 9.061 3.738 10.280 13.220
16 9.628 18.940 96.560 4.304 8.042 0.580 9.713 20.870 7.815 4.191 9.628 10.760
17 10.310 14.300 47.290 4.446 10.310 1.042 6.994 12.350 36.810 6.711 9.458 9.543
18 11.410 12.230 27.440 4.587 15.570 1.509 5.720 8.297 34.550 16.450 8.863 9.571
19 9.599 10.870 31.430 4.871 11.530 1.509 6.003 6.994 26.510 20.930 8.070 15.940
20 8.920 9.656 40.490 5.125 7.249 1.212 9.854 15.520 13.900 19.140 7.277 12.970
21 14.500 9.118 35.960 4.871 8.438 0.736 6.428 10.850 21.100 38.230 6.711 37.100
22 46.440 8.580 23.020 4.871 6.711 1.048 5.125 7.532 27.720 27.440 8.580 15.940
23 25.490 8.070 16.760 4.531 5.380 0.425 3.087 6.711 84.670 34.260 8.014 14.160
24 16.570 12.540 13.790 5.862 4.163 0.900 3.256 10.620 37.950 45.310 6.994 11.440
25 13.680 57.770 11.920 4.757 2.600 1.048 2.761 77.870 22.260 24.240 6.994 9.684
26 46.440 43.610 11.470 4.616 2.585 1.203 2.642 45.590 20.810 18.940 6.003 9.231
27 31.430 20.390 15.570 2.973 3.710 1.048 10.650 16.590 14.610 16.960 5.862 8.722
28 26.870 15.430 11.550 2.747 1.996 1.826 13.990 14.410 11.550 49.840 5.409 12.380
29 38.790 9.769 5.097 2.316 0.736 6.966 9.543 11.580 62.860 5.409 10.700
30 29.730 8.552 3.341 2.124 1.359 4.021 7.532 10.080 144.100 5.097 11.610
31 28.150 8.410 2.322 3.426 5.550 60.320 23.330
Average 28.060 27.640 22.520 5.197 4.705 1.545 7.128 13.110 17.350 21.530 19.660 18.930
Lowest 8.920 8.070 8.410 2.747 1.665 0.425 1.509 1.523 4.446 3.426 5.097 4.248
Highest 136.200 79.570 96.560 8.382 18.490 3.087 41.910 77.870 84.670 144.100 82.120 122.600
Monthly total
(million cu m) 75.16 66.86 60.31 13.47 12.60 4.00 19.09 35.10 44.96 57.66 50.95 50.71
Runoff (mm) 99 88 79 18 17 5 25 46 59 76 67 67
Rainfall (mm) 104 91 86 10 43 46 99 150 135 132 58 112
Statistics of monthly data for previous record (Oct 1955 to Dec 1956)
Mean Avg. 24.320 13.240 16.920 6.335 6.208 3.816 8.200 41.340 22.270 8.827 8.294 25.860
flows: Low 24.320 13.240 16.920 6.335 6.208 3.816 8.200 41.340 22.270 6.597 7.409 24.330
(year) 1956 1956 1956 1956 1956 1956 1956 1956 1956 1955 1956 1956
High 24.320 13.240 16.920 6.335 6.208 3.816 8.200 41.340 22.270 11.060 9.180 27.390
(year) 1956 1956 1956 1956 1956 1956 1956 1956 1956 1956 1955 1955
Runoff: Avg. 86 44 60 22 22 13 29 146 76 31 28 91
Low 86 44 60 22 22 13 29 146 76 23 25 86
High 86 44 60 22 22 13 29 146 76 39 31 97
Rainfall: Avg. 100 62 56 51 75 77 80 132 90 68 49 136
Low 77 51 46 43 41 76 35 38 68 61 33 117
High 123 72 65 58 108 78 124 226 112 74 64 155
Summary statistics Factors affecting runoff
1957
For 1957 For record As % of $ Reservoir(s) in catchment.
preceding 1957 pre-1957 $ Abstraction for public water supplies.
Mean flow 15.570 15.540 100 $ Flow reduced by industrial and/or
Lowest yearly mean 15.530 1956 agricultural abstractions.
Highest yearly mean 15.530 1956 $ Augmentation from surface water and/or
Lowest monthly mean 1.545 Jun 3.816 Jun 1956 groundwater.
Highest monthly mean 28.060 Jan 41.340 Aug 1956
Lowest daily mean 0.425 23 Jun 1.048 2 Oct 1955
Highest daily mean 144.100 30 Oct 131.400 2 Mar 1956
10% exceedance 37.120 33.500 111
50% exceedance 9.061 7.936 114
95% exceedance 1.510 2.997 50
Annual total (million cu m) 491.00 490.70 100
Annual runoff (mm) 647 647 100
Annual rainfall (mm) 1066 976 109
{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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