027002 Wharfe at Flint Mill Weir 1959
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 79.570 10.140 7.872 13.960 12.380 2.435 2.166 2.546 1.189 1.337 4.729 16.680
2 102.500 9.203 8.637 12.970 11.240 2.704 5.182 2.152 1.682 1.543 5.069 14.950
3 41.060 8.099 6.994 9.203 8.099 2.452 6.201 2.152 1.665 1.257 3.993 19.060
4 22.170 7.476 17.590 6.994 7.872 2.520 3.455 2.152 1.744 1.133 3.879 12.690
5 16.400 7.872 11.100 6.428 6.428 2.704 3.341 2.152 1.274 1.048 3.455 10.450
6 13.960 7.108 9.939 7.872 6.116 2.370 3.625 2.152 1.178 0.991 3.030 16.910
7 12.260 5.890 30.020 17.190 5.777 2.452 2.498 2.152 1.133 1.523 1.937 52.950
8 10.820 5.890 20.810 31.150 6.201 3.256 2.444 2.067 1.722 1.594 2.260 61.170
9 10.250 7.108 12.040 22.260 6.201 3.002 2.370 1.954 1.532 1.269 12.910 40.490
10 7.872 6.116 9.203 20.050 5.692 3.455 2.166 1.778 1.651 1.291 12.800 28.320
11 7.872 5.777 8.099 15.890 6.003 3.341 2.110 2.033 1.628 1.274 11.530 18.070
12 9.571 5.777 14.810 33.700 4.559 2.704 1.625 1.849 1.300 1.243 8.382 13.560
13 7.957 5.578 12.970 19.060 4.049 2.282 2.110 2.027 1.133 1.436 9.260 11.300
14 6.768 4.502 8.976 17.100 3.341 2.231 2.370 2.022 1.133 1.430 48.140 15.910
15 6.315 6.315 13.110 13.340 3.341 2.973 2.444 1.880 1.600 1.229 50.400 12.800
16 5.777 12.040 11.640 21.440 2.888 2.452 2.520 1.962 1.631 1.577 27.440 13.680
17 7.249 9.458 8.240 40.490 2.704 2.370 14.330 2.410 1.603 1.880 19.600 41.910
18 34.830 8.240 7.362 23.360 2.888 2.053 6.881 1.807 1.405 1.339 29.730 43.040
19 80.140 6.201 6.428 15.800 2.888 2.231 5.069 1.447 1.164 1.175 31.430 34.550
20 55.220 6.315 6.428 12.380 3.115 2.452 4.446 1.444 1.133 6.456 47.860 80.420
21 51.540 5.267 5.154 10.360 3.455 1.716 3.200 1.396 1.373 16.450 33.980 54.650
22 124.900 7.872 5.380 8.637 3.256 2.370 2.888 1.444 1.235 22.260 17.870 62.860
23 49.560 9.458 6.654 7.674 2.973 2.260 2.616 1.189 1.393 7.702 19.060 58.620
24 23.500 14.070 5.578 6.994 2.520 2.297 2.297 1.189 1.419 4.276 15.600 28.290
25 15.800 12.150 5.465 6.654 2.803 2.370 2.110 1.594 1.515 10.310 20.330 33.700
26 13.220 12.040 6.003 28.150 2.973 2.407 1.991 1.778 1.515 25.170 96.000 78.720
27 11.240 10.250 6.428 23.140 2.704 2.110 4.191 1.617 1.365 135.400 31.720 158.900
28 9.571 7.674 10.360 23.190 2.704 1.991 3.936 1.419 1.189 30.300 17.870 70.230
29 9.203 8.722 14.920 2.803 2.786 4.304 1.501 1.430 12.150 22.370 47.860
30 12.490 25.000 12.150 2.520 2.297 3.625 1.232 1.623 8.212 25.400 61.170
31 14.330 11.530 2.166 3.115 1.133 6.513 32.000
Average 28.190 7.996 10.600 16.750 4.602 2.501 3.601 1.795 1.419 10.020 21.270 40.190
Lowest 5.777 4.502 5.154 6.428 2.166 1.716 1.625 1.133 1.133 0.991 1.937 10.450
Highest 124.900 14.070 30.020 40.490 12.380 3.455 14.330 2.546 1.744 135.400 96.000 158.900
Monthly total
(million cu m) 75.51 19.34 28.39 43.42 12.33 6.48 9.64 4.81 3.68 26.85 55.13 107.60
Runoff (mm) 99 25 37 57 16 9 13 6 5 35 73 142
Rainfall (mm) 99 20 61 104 25 48 71 18 8 114 142 203
Statistics of monthly data for previous record (Oct 1955 to Dec 1958)
Mean Avg. 28.450 29.370 18.350 6.175 9.566 6.603 9.607 23.050 18.640 16.150 10.780 23.000
flows: Low 24.320 13.240 15.600 5.197 4.705 1.545 7.128 13.110 16.290 6.597 6.876 18.930
(year) 1956 1956 1958 1957 1957 1957 1957 1957 1958 1955 1958 1957
High 32.960 47.220 22.520 6.993 17.780 14.450 13.490 41.340 22.270 25.440 19.660 27.390
(year) 1958 1958 1957 1958 1958 1958 1958 1956 1956 1958 1957 1955
Runoff: Avg. 100 94 65 21 34 23 34 81 64 57 37 81
Low 86 44 55 18 17 5 25 46 56 23 23 67
High 116 151 79 24 63 49 48 146 76 90 67 97
Rainfall: Avg. 102 98 61 35 79 78 89 127 109 92 48 129
Low 77 51 46 10 41 46 35 38 68 61 33 112
High 123 178 86 58 122 112 124 226 135 132 64 155
Summary statistics Factors affecting runoff
1959
For 1959 For record As % of $ Reservoir(s) in catchment.
preceding 1959 pre-1959 $ Abstraction for public water supplies.
Mean flow 12.470 16.620 75 $ Flow reduced by industrial and/or
Lowest yearly mean 15.530 1956 agricultural abstractions.
Highest yearly mean 19.290 1958 $ Augmentation from surface water and/or
Lowest monthly mean 1.419 Sep 1.545 Jun 1957 groundwater.
Highest monthly mean 40.190 Dec 47.220 Feb 1958
Lowest daily mean 0.991 6 Oct 0.425 23 Jun 1957
Highest daily mean 158.900 27 Dec 182.400 11 Feb 1958
10% exceedance 30.960 39.120 79
50% exceedance 6.072 9.048 67
95% exceedance 1.242 2.317 54
Annual total (million cu m) 393.30 524.50 75
Annual runoff (mm) 518 691 75
Annual rainfall (mm) 913 1047 87
{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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