027002 Wharfe at Flint Mill Weir 1983
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 34.810 91.120 22.050 22.660 47.840 35.710 4.250 3.258 2.606 3.540 6.276 8.665
2 28.740 33.970 19.850 16.230 47.070 27.470 5.182 2.706 3.450 4.305 8.111 7.454
3 77.440 23.180 64.210 12.760 36.540 23.400 6.867 2.588 8.677 7.804 9.262 6.558
4 71.490 17.740 30.850 12.500 24.050 18.140 4.894 2.428 6.791 7.204 14.950 5.985
5 55.700 26.810 19.550 15.860 18.540 14.030 3.981 2.685 4.392 12.160 11.220 7.105
6 86.040 34.540 18.590 13.290 47.210 10.760 3.584 2.168 3.831 12.710 8.534 8.305
7 53.040 28.380 15.180 11.030 38.850 9.306 3.367 2.231 3.255 19.990 7.188 6.332
8 46.040 19.890 11.520 11.360 66.440 17.710 3.298 2.209 3.543 38.190 6.040 25.990
9 47.430 16.130 9.545 13.970 58.730 13.230 3.156 2.320 7.448 56.590 5.441 216.200
10 44.660 14.140 8.577 28.190 37.670 11.990 3.221 2.268 6.667 65.530 5.043 54.710
11 33.800 12.430 8.109 31.870 29.970 9.823 3.140 2.117 8.953 45.830 4.795 26.600
12 29.590 11.560 7.705 19.090 30.400 10.640 2.973 2.065 6.139 64.540 4.572 18.800
13 33.620 10.900 7.448 13.790 29.750 8.830 3.023 2.128 3.998 36.080 4.396 21.380
14 51.300 10.550 13.600 12.230 25.020 9.370 2.880 2.189 3.665 23.040 4.176 36.450
15 33.590 10.550 14.460 10.450 30.110 13.060 2.831 2.227 3.897 27.450 3.970 73.300
16 21.780 10.850 10.320 9.486 20.610 9.749 2.790 6.692 30.200 117.800 3.865 31.600
17 17.730 10.650 20.060 9.120 16.570 8.048 3.930 8.947 21.040 55.500 3.747 27.250
18 29.160 9.773 31.150 8.154 40.760 7.102 3.168 4.190 29.020 36.620 3.627 24.500
19 17.660 9.115 59.850 8.666 28.200 6.210 3.059 3.188 13.560 27.250 3.567 37.790
20 15.650 8.601 23.330 24.490 17.820 5.598 2.974 3.060 13.310 18.390 3.475 54.310
21 25.360 8.154 40.890 40.130 14.600 5.020 2.888 2.815 33.900 14.230 3.422 84.300
22 17.460 7.644 38.370 48.610 13.740 4.691 2.804 2.622 13.870 11.550 3.316 58.860
23 13.290 7.277 77.140 50.590 11.890 8.287 2.779 2.554 8.324 10.250 3.201 66.790
24 20.690 7.087 47.460 22.770 10.300 6.303 2.793 2.429 6.246 9.210 3.132 108.700
25 21.270 7.131 30.530 23.270 9.269 5.136 3.306 2.378 5.440 8.459 3.267 52.230
26 14.600 19.410 25.910 46.250 8.388 4.893 4.049 2.318 4.906 7.820 62.720 50.440
27 39.610 42.990 19.250 47.510 8.049 4.342 3.085 2.274 4.729 7.086 46.170 54.840
28 86.900 33.940 15.970 46.530 15.870 4.497 2.820 2.316 4.369 6.567 20.110 49.300
29 55.480 16.510 54.470 12.900 4.281 2.662 2.237 4.106 6.088 15.540 39.240
30 27.610 28.710 31.140 9.508 4.568 2.562 2.133 3.833 5.584 10.940 32.770
31 55.320 25.640 9.039 3.955 2.269 6.919 24.080
Average 38.930 19.450 25.240 23.880 26.310 10.740 3.428 2.839 9.139 24.980 9.802 42.610
Lowest 13.290 7.087 7.448 8.154 8.049 4.281 2.562 2.065 2.606 3.540 3.132 5.985
Highest 86.900 91.120 77.140 54.470 66.440 35.710 6.867 8.947 33.900 117.800 62.720 216.200
Monthly total
(million cu m) 104.30 47.05 67.59 61.90 70.48 27.84 9.18 7.60 23.69 66.90 25.41 114.10
Runoff (mm) 137 62 89 82 93 37 12 10 31 88 33 150
Rainfall (mm) 164 51 104 144 142 51 42 47 111 141 56 233
Statistics of monthly data for previous record (Oct 1955 to Dec 1982)
Mean Avg. 26.920 23.120 21.580 15.230 11.080 7.497 7.917 11.800 13.840 17.850 24.050 26.910
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 39.260 54.590 53.940 35.240 26.750 18.530 16.440 41.340 33.520 54.000 51.090 62.090
(year) 1961 1966 1981 1970 1967 1972 1963 1956 1968 1967 1963 1965
Runoff: Avg. 95 74 76 52 39 26 28 42 47 63 82 95
Low 16 9 24 15 8 5 6 4 5 11 23 36
High 139 174 190 120 94 63 58 146 115 191 174 219
Rainfall: Avg. 108 84 89 72 76 78 86 100 105 104 113 119
Low 41 20 28 8 13 18 22 18 8 32 33 41
High 165 194 222 147 181 183 185 226 241 225 211 224
Summary statistics Factors affecting runoff
1983
For 1983 For record As % of $ Reservoir(s) in catchment.
preceding 1983 pre-1983 $ Abstraction for public water supplies.
Mean flow 19.850 17.300 115 $ 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 2.839 Aug 0.991 Aug 1976 groundwater.
Highest monthly mean 42.610 Dec 62.090 Dec 1965
Lowest daily mean 2.065 12 Aug 0.425 23 Jun 1957
Highest daily mean 216.200 9 Dec 288.400 3 Jan 1982
10% exceedance 47.890 40.930 117
50% exceedance 11.360 9.682 117
95% exceedance 2.458 2.255 109
Annual total (million cu m) 626.00 545.90 115
Annual runoff (mm) 825 719 115
Annual rainfall (mm) 1286 1134 113
{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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