028026 Anker at Polesworth 1998
Measuring authority: EA Grid reference: 43 (SK) 263 034 Catchment area (sq km): 368.0
First year: 1966 Level stn. (m OD): 60.40 Max alt. (m OD): 278
Daily mean gauged discharges (cubic metres per second)
DAY JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1 5.277 2.197 1.636 2.835 2.253 1.298 2.182 1.513 1.300 6.024 13.410 2.965
2 21.020 2.145 1.614 5.241 2.136 7.476 1.879 1.378 1.521 3.525 9.980 2.804
3 31.500 2.015 2.419 12.730 2.030 4.777 1.734 1.199 1.245 2.531 12.650 2.865
4 24.090 1.975 5.950 8.147 1.983 3.035 1.623 1.328 1.084 1.995 7.252 2.970
5 23.200 1.913 3.777 6.374 2.031 2.063 1.539 1.252 3.589 1.944 5.143 2.715
6 18.690 1.943 10.460 5.781 2.100 1.890 1.523 1.049 3.379 2.539 4.286 2.398
7 13.720 2.233 14.240 9.068 1.885 2.533 1.515 0.954 1.662 2.394 3.775 2.252
8 11.880 1.917 6.230 20.300 1.799 2.219 1.408 0.930 1.759 1.884 8.032 5.267
9 9.330 1.871 4.183 16.130 1.706 2.392 1.326 0.902 2.100 1.726 11.970 6.972
10 6.649 1.814 3.932 37.630 1.813 1.964 1.251 0.852 1.872 1.801 7.017 5.251
11 5.474 1.784 4.187 28.280 2.471 2.835 1.340 0.845 1.662 1.696 4.594 5.305
12 4.599 1.761 3.629 9.579 1.936 2.454 1.331 0.834 1.687 1.550 4.147 5.789
13 4.592 1.716 3.445 6.146 1.776 2.415 1.301 0.828 2.568 1.555 3.600 10.430
14 4.644 1.756 2.993 4.945 1.686 2.882 1.167 0.851 1.722 1.808 3.757 8.243
15 4.378 1.673 2.663 7.148 1.636 3.657 1.087 0.943 1.377 1.836 3.607 8.338
16 4.016 1.659 2.533 7.043 1.495 4.129 1.082 1.131 1.308 1.852 3.077 9.527
17 3.522 1.593 2.366 4.894 1.369 2.845 1.116 0.946 1.272 2.136 2.805 6.222
18 14.290 1.613 2.202 3.969 1.331 3.179 1.281 0.865 1.203 2.057 2.640 5.189
19 18.400 1.655 2.071 3.542 1.375 3.574 1.151 0.855 1.163 1.900 2.516 4.957
20 7.370 1.642 2.007 3.390 1.322 2.524 1.100 0.873 1.086 1.761 2.388 4.190
21 5.192 1.790 1.976 3.256 1.305 2.023 1.115 0.887 1.041 1.729 2.252 3.665
22 4.424 1.631 1.939 3.725 1.334 1.712 1.145 0.912 1.050 2.132 2.207 3.489
23 3.817 1.503 1.871 7.382 1.306 1.930 1.060 1.289 1.071 6.133 2.114 6.853
24 3.339 1.486 1.990 7.190 1.302 1.716 1.065 3.125 1.065 14.150 2.774 6.584
25 3.055 1.488 3.215 5.772 1.353 1.582 1.086 1.891 1.072 20.070 2.981 20.430
26 2.795 1.533 4.301 4.426 1.367 2.454 1.074 1.388 1.237 8.684 2.713 34.390
27 2.744 1.627 3.804 3.633 1.349 7.964 1.024 1.364 2.473 11.420 2.728 16.250
28 2.588 1.791 3.092 3.149 1.284 8.554 1.033 1.236 1.526 39.350 3.658 8.336
29 2.432 3.071 2.759 1.221 3.572 1.060 1.156 1.301 20.280 4.122 6.119
30 2.374 3.619 2.425 1.193 2.588 1.212 1.086 4.352 10.220 3.348 5.097
31 2.239 3.004 1.216 1.424 1.050 9.274 4.813
Average 8.763 1.776 3.691 8.230 1.625 3.141 1.298 1.152 1.692 6.063 4.851 7.119
Lowest 2.239 1.486 1.614 2.425 1.193 1.298 1.024 0.828 1.041 1.550 2.114 2.252
Highest 31.500 2.233 14.240 37.630 2.471 8.554 2.182 3.125 4.352 39.350 13.410 34.390
Monthly total
(million cu m) 23.47 4.30 9.89 21.33 4.35 8.14 3.48 3.09 4.38 16.24 12.57 19.07
Runoff (mm) 64 12 27 58 12 22 9 8 12 44 34 52
Rainfall (mm) 75 12 64 100 15 129 24 45 80 113 42 73
Statistics of monthly data for previous record (Sep 1966 to Dec 1997----incomplete or missing months total 0.2 years)
Mean Avg. 5.345 5.027 3.934 2.874 2.164 1.839 1.323 1.353 1.408 1.998 2.939 4.480
flows: Low 1.299 0.953 0.813 0.657 0.685 0.484 0.343 0.405 0.711 0.729 0.855 1.174
(year) 1976 1976 1976 1976 1976 1976 1976 1976 1977 1970 1978 1975
High 9.572 16.200 9.233 6.628 8.389 4.650 5.580 4.173 3.363 8.109 7.309 9.474
(year) 1988 1977 1979 1987 1969 1973 1968 1980 1992 1993 1992 1978
Runoff: Avg. 39 33 29 20 16 13 10 10 10 15 21 33
Low 9 6 6 5 5 3 3 3 5 5 6 9
High 70 106 67 47 61 33 41 30 24 59 51 69
Rainfall: Avg. 57 50 47 48 57 57 51 60 56 56 59 63
Low 16 9 14 7 11 9 12 15 10 7 28 20
High 103 138 92 100 141 132 111 110 118 127 129 148
Summary statistics Factors affecting runoff
1998
For 1998 For record As % of $ Flow influenced by groundwater abstraction
preceding 1998 pre-1998 and/or recharge.
Mean flow 4.132 2.881 143 $ Augmentation from effluent returns.
Lowest yearly mean 1.213 1976
Highest yearly mean 4.114 1993
Lowest monthly mean 1.152 Aug 0.343 Jul 1976
Highest monthly mean 8.763 Jan 16.200 Feb 1977
Lowest daily mean 0.828 13 Aug 0.234 26 Aug 1976
Highest daily mean 39.350 28 Oct 56.720 24 Jan 1988
10% exceedance 8.533 5.860 146
50% exceedance 2.279 1.621 141
95% exceedance 1.043 0.661 158
Annual total (million cu m) 130.30 90.92 143
Annual runoff (mm) 354 247 143
Annual rainfall (mm) 772 661 117
{1961-90 rainfall average (mm) 653}
Station and catchment description
Crump profile weir with flanking floodbanks to contain out-of-channel flows. Cableway and d/s recorder. Low modular limit
and prone to weed growth, causing variable drowning and uncertainty with high flows. Substantial modification owing to
PWS imports to the catchment. Quite responsive.
Predominantly agricultural catchment (although containing Nuneaton and Hinkley). Lower reaches drain sandstone of the
Coal Measures. Sherwood sandstone and Mercia Mudstone over the remainder of the catchment are widely blanketed with
Boulder Clay.
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