027002 Wharfe at Flint Mill Weir 1968
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 14.850 25.330 8.733 101.500 9.209 7.156 35.540 4.219 3.322 55.650 146.600 14.820
2 13.540 24.630 7.546 53.910 9.158 6.227 84.710 4.021 4.174 66.540 187.300 13.980
3 20.080 16.490 6.997 27.640 7.855 5.788 71.670 3.964 5.995 45.700 69.320 12.470
4 21.340 13.960 7.886 22.290 13.500 5.547 37.780 4.157 4.938 29.850 37.320 11.320
5 16.290 18.770 23.650 19.570 21.700 5.216 23.850 4.228 4.089 21.460 27.660 10.650
6 22.610 21.970 22.590 17.500 49.390 5.406 16.120 3.959 4.208 17.630 22.910 10.240
7 16.460 17.830 11.670 14.170 25.230 5.652 12.530 3.840 6.049 15.280 26.170 9.738
8 12.640 16.190 9.305 12.400 27.920 5.570 11.660 3.500 4.842 13.270 26.390 9.355
9 11.230 15.110 7.603 11.040 30.090 5.380 10.400 3.593 4.344 11.750 18.230 8.951
10 9.750 16.940 7.555 10.100 26.420 4.888 9.186 3.313 4.038 27.320 15.450 8.648
11 9.421 15.620 8.017 9.486 46.570 5.332 8.566 3.228 22.330 24.170 19.620 8.334
12 9.982 15.720 7.725 8.897 56.450 5.165 8.472 3.503 149.800 37.020 18.010 8.073
13 9.605 18.980 7.226 7.926 39.370 5.015 8.705 3.622 47.580 38.020 14.880 7.867
14 109.700 23.840 7.300 7.504 59.070 4.902 8.291 3.789 23.900 25.670 12.850 7.162
15 57.860 17.150 9.619 6.994 26.430 4.534 10.960 4.834 16.470 18.980 11.570 7.055
16 104.800 13.810 13.470 6.541 34.500 4.318 20.280 6.179 12.760 28.120 9.896 8.965
17 100.300 11.460 31.250 7.164 26.650 3.851 16.090 5.100 10.420 25.050 9.288 17.290
18 50.720 10.900 21.390 7.787 20.220 4.044 10.510 4.709 8.985 18.530 9.517 43.400
19 40.080 11.300 96.620 10.280 16.760 4.970 9.784 5.389 8.410 13.840 9.248 36.800
20 26.030 10.490 160.300 20.990 14.880 5.307 9.129 20.720 70.100 12.180 9.310 49.350
21 19.850 9.996 51.590 14.320 12.280 5.754 8.665 11.920 97.230 12.470 9.503 40.190
22 16.760 9.308 35.810 10.820 10.620 5.969 8.135 7.014 74.570 11.210 15.730 74.930
23 14.700 8.739 202.300 9.481 9.727 13.500 7.682 5.448 88.120 10.150 21.700 52.440
24 12.990 7.733 156.000 8.407 9.144 20.010 7.161 4.723 42.360 9.469 29.740 27.300
25 11.860 7.408 65.140 8.053 8.572 14.910 6.756 4.330 28.950 8.979 19.130 20.140
26 11.100 7.915 34.800 7.558 8.039 12.020 5.859 4.154 54.530 7.881 21.300 16.340
27 9.665 7.770 30.040 7.235 8.719 27.930 5.210 4.007 45.410 7.858 58.540 13.250
28 12.210 7.813 21.430 7.130 9.953 51.400 4.851 3.500 47.590 69.180 31.670 11.250
29 11.050 8.430 17.030 7.190 8.424 26.720 5.604 3.775 54.180 48.540 21.320 10.760
30 46.210 14.550 8.158 7.719 15.000 5.326 3.596 56.000 35.360 17.610 10.050
31 28.840 13.270 7.462 4.953 3.135 83.030 9.559
Average 28.150 14.190 36.080 15.730 21.360 9.916 15.950 5.015 33.520 27.420 31.590 19.050
Lowest 9.421 7.408 6.997 6.541 7.462 3.851 4.851 3.135 3.322 7.858 9.248 7.055
Highest 109.700 25.330 202.300 101.500 59.070 51.400 84.710 20.720 149.800 83.030 187.300 74.930
Monthly total
(million cu m) 75.39 35.56 96.63 40.78 57.20 25.70 42.72 13.43 86.89 73.45 81.89 51.03
Runoff (mm) 99 47 127 54 75 34 56 18 115 97 108 67
Rainfall (mm) 101 51 148 69 114 106 113 65 241 139 105 75
Statistics of monthly data for previous record (Oct 1955 to Dec 1967)
Mean Avg. 25.610 24.010 17.620 15.010 11.770 6.539 9.180 15.400 14.300 17.750 20.940 28.880
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 22.320 54.000 51.090 62.090
(year) 1961 1966 1963 1966 1967 1958 1963 1956 1965 1967 1963 1965
Runoff: Avg. 90 77 62 51 42 22 32 54 49 63 72 102
Low 16 9 24 18 14 5 13 6 5 23 23 36
High 139 174 128 100 94 49 58 146 76 191 174 219
Rainfall: Avg. 101 85 68 75 77 72 94 116 97 105 99 128
Low 41 20 28 10 25 33 35 18 8 46 33 41
High 165 194 127 130 181 140 185 226 184 225 211 224
Summary statistics Factors affecting runoff
1968
For 1968 For record As % of $ Reservoir(s) in catchment.
preceding 1968 pre-1968 $ Abstraction for public water supplies.
Mean flow 21.530 17.230 125 $ 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 5.015 Aug 1.419 Sep 1959 groundwater.
Highest monthly mean 36.080 Mar 62.090 Dec 1965
Lowest daily mean 3.135 31 Aug 0.425 23 Jun 1957
Highest daily mean 202.300 23 Mar 233.600 4 Dec 1960
10% exceedance 50.110 40.520 124
50% exceedance 11.760 9.367 126
95% exceedance 4.040 2.342 173
Annual total (million cu m) 680.80 543.70 125
Annual runoff (mm) 897 716 125
Annual rainfall (mm) 1327 1117 119
{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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