028026 Anker at Polesworth 2001
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 23.660 3.704 5.367 4.250 3.297 1.767 1.368 1.235 1.229 2.756 2.294 14.720
2 25.560 7.498 4.317 4.150 3.026 1.832 1.311 1.232 1.186 2.251 2.104 11.850
3 17.720 14.030 3.760 5.899 2.996 1.860 1.268 1.324 1.365 1.651 1.937 5.782
4 10.270 23.440 3.336 16.480 2.738 1.688 1.216 1.471 1.405 1.440 1.876 6.777
5 7.842 28.560 2.935 15.660 2.505 1.651 1.183 1.378 1.429 1.448 1.740 7.188
6 5.889 23.530 3.847 18.330 2.394 1.701 1.267 1.521 1.342 1.531 1.751 5.767
7 4.914 14.930 8.065 15.230 2.339 1.670 1.570 1.939 1.288 1.929 2.045 4.281
8 4.304 7.551 5.326 13.030 2.388 1.630 4.888 1.545 1.211 2.987 2.502 3.400
9 3.949 5.500 4.508 13.100 2.624 1.613 2.919 1.363 1.204 2.488 1.975 3.003
10 3.607 4.841 4.237 7.945 3.137 1.697 1.802 1.336 1.157 1.923 1.734 2.751
11 3.256 4.668 3.962 5.897 2.594 1.662 1.570 1.273 1.136 1.639 1.699 2.555
12 3.006 14.270 4.213 4.947 2.226 1.596 1.393 1.368 1.255 1.567 2.020 2.484
13 2.874 11.510 5.589 4.285 2.926 1.563 1.472 1.569 1.951 1.433 2.087 2.326
14 2.765 6.499 4.406 3.942 6.186 1.642 1.773 1.410 1.971 1.380 1.892 2.169
15 2.784 5.270 3.743 4.154 10.770 2.816 1.399 1.307 1.460 2.846 1.755 2.058
16 2.645 4.495 3.757 3.902 7.167 4.837 1.318 1.460 1.339 5.348 1.716 2.021
17 2.532 3.972 9.197 3.473 13.980 3.592 1.663 1.660 1.377 2.634 1.676 1.960
18 2.473 3.664 7.231 3.588 18.960 2.164 8.833 1.464 1.305 2.292 1.682 1.960
19 2.413 3.492 5.648 3.278 6.354 1.879 14.380 2.343 1.379 2.152 1.662 1.927
20 2.353 3.375 4.578 3.045 4.388 1.792 6.100 2.584 1.606 3.887 1.639 1.922
21 2.800 3.264 7.377 2.830 3.512 1.636 2.872 1.718 1.419 5.278 1.629 2.079
22 4.403 3.216 10.990 3.787 3.071 1.603 2.246 1.393 1.262 10.560 2.120 2.232
23 13.610 3.252 12.890 7.198 2.729 1.582 1.849 1.294 1.254 12.810 1.911 1.890
24 25.640 2.930 7.811 7.582 2.528 1.465 1.708 1.257 1.420 7.043 1.783 1.976
25 9.123 2.788 5.890 8.106 2.312 1.383 1.580 1.235 1.787 3.743 2.338 3.693
26 6.004 3.838 4.912 6.372 2.258 1.318 1.438 1.209 1.727 7.699 2.840 3.416
27 4.760 7.770 5.344 4.903 2.206 1.293 1.331 1.157 1.910 11.890 2.927 2.911
28 3.977 7.255 11.180 5.762 2.079 1.255 1.312 1.121 1.542 4.641 2.784 2.728
29 3.461 9.355 5.186 1.898 1.296 1.283 1.109 1.652 3.232 4.647 2.456
30 3.451 6.284 3.930 1.884 1.646 1.248 1.118 2.018 2.868 8.708 2.265
31 3.487 5.073 1.817 1.230 1.175 2.738 1.975
Average 6.953 8.183 5.972 7.008 4.171 1.838 2.477 1.438 1.453 3.809 2.316 3.694
Lowest 2.353 2.788 2.935 2.830 1.817 1.255 1.183 1.109 1.136 1.380 1.629 1.890
Highest 25.640 28.560 12.890 18.330 18.960 4.837 14.380 2.584 2.018 12.810 8.708 14.720
Monthly total
(million cu m) 18.62 19.80 16.00 18.16 11.17 4.76 6.64 3.85 3.77 10.20 6.00 9.89
Runoff (mm) 51 54 43 49 30 13 18 10 10 28 16 27
Rainfall (mm) 40 73 61 85 62 41 70 52 57 93 45 25
Statistics of monthly data for previous record (Sep 1966 to Dec 2000----incomplete or missing months total 0.2 years)
Mean Avg. 5.563 4.897 3.981 3.164 2.169 1.966 1.314 1.357 1.483 2.344 3.290 4.797
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 11.320 16.200 9.233 8.230 8.389 4.948 5.580 4.173 3.363 8.109 13.150 10.460
(year) 1999 1977 1979 1998 1969 1999 1968 1980 1992 1993 2000 2000
Runoff: Avg. 40 32 29 22 16 14 10 10 10 17 23 35
Low 9 6 6 5 5 3 3 3 5 5 6 9
High 82 106 67 58 61 35 41 30 24 59 93 76
Rainfall: Avg. 58 49 48 51 56 60 49 59 59 60 60 64
Low 16 9 14 7 11 9 11 15 10 7 28 20
High 106 138 92 110 141 132 111 110 118 127 129 148
Summary statistics Factors affecting runoff
2001
For 2001 For record As % of $ Flow influenced by groundwater abstraction
preceding 2001 pre-2001 and/or recharge.
Mean flow 4.086 3.019 135 $ Augmentation from effluent returns.
Lowest yearly mean 1.213 1976
Highest yearly mean 4.911 2000
Lowest monthly mean 1.438 Aug 0.343 Jul 1976
Highest monthly mean 8.183 Feb 16.200 Feb 1977
Lowest daily mean 1.109 29 Aug 0.234 26 Aug 1976
Highest daily mean 28.560 5 Feb 70.410 6 Nov 2000
10% exceedance 8.389 6.221 135
50% exceedance 2.529 1.700 149
95% exceedance 1.243 0.673 185
Annual total (million cu m) 128.90 95.27 135
Annual runoff (mm) 350 259 135
Annual rainfall (mm) 704 673 105
{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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