028026 Anker at Polesworth 1996
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 2.443 1.754 3.442 1.908 2.544 1.081 1.208 0.895 0.909 0.836 1.265 1.780
2 2.648 1.824 3.177 1.760 2.015 1.053 1.293 0.841 0.902 0.843 1.217 1.788
3 2.718 1.741 2.966 1.721 1.563 1.062 1.245 0.815 0.925 0.833 1.002 3.823
4 3.468 1.685 2.765 1.677 1.385 1.025 1.217 0.794 0.929 1.055 1.507 3.234
5 3.747 1.725 2.570 1.705 1.257 1.013 1.047 0.756 0.898 0.985 1.337 2.124
6 5.200 1.857 2.447 1.699 1.266 0.987 1.265 0.774 0.834 0.867 1.321 1.695
7 7.385 1.828 2.413 1.632 1.254 1.158 1.124 1.037 0.824 0.857 1.636 1.491
8 6.843 1.754 2.382 1.591 1.217 1.433 0.998 0.938 0.803 1.031 1.269 1.366
9 12.810 6.293 2.556 1.610 1.187 1.080 0.875 0.889 0.774 1.241 1.119 1.313
10 7.243 7.626 2.263 1.692 1.213 0.980 0.848 0.972 0.780 0.968 1.011 1.283
11 5.162 5.504 2.463 1.712 1.212 1.208 0.873 1.253 0.792 0.884 1.041 1.254
12 5.251 13.280 3.141 2.915 1.190 1.356 0.883 0.974 0.794 0.843 1.257 1.221
13 5.233 10.150 2.791 3.376 1.175 1.122 0.852 0.896 0.790 0.803 1.144 1.226
14 4.018 6.003 2.573 2.359 1.174 0.994 0.834 0.857 0.786 0.800 1.075 1.166
15 3.281 4.555 2.424 2.065 1.145 0.936 0.824 0.814 0.774 0.861 1.094 1.139
16 2.898 3.859 2.324 2.044 1.148 0.884 0.780 0.770 0.744 0.807 1.060 1.147
17 2.715 3.357 2.258 1.984 1.166 0.863 0.742 0.799 0.737 0.804 1.756 1.176
18 2.552 4.321 2.124 1.851 1.210 0.886 0.707 0.762 0.742 1.145 2.316 1.706
19 2.373 4.870 2.054 1.901 1.718 0.879 0.735 0.700 0.759 1.054 2.486 5.720
20 2.294 3.792 2.069 1.728 1.262 0.843 0.757 0.687 0.747 1.132 4.071 9.033
21 2.173 3.817 2.926 1.660 1.476 0.870 0.745 0.954 0.762 1.256 3.248 4.149
22 2.046 4.922 2.952 1.607 1.661 0.843 0.718 0.938 0.752 1.055 1.981 2.685
23 1.956 7.640 3.436 3.114 1.589 0.826 0.738 2.242 0.745 0.952 1.591 2.131
24 2.053 11.250 3.384 1.959 1.848 0.818 0.850 1.861 0.752 0.912 2.355 1.838
25 1.876 11.400 3.020 1.596 1.546 0.839 1.272 1.537 0.790 1.041 3.772 1.579
26 1.707 10.630 2.689 1.525 1.246 0.864 0.913 1.654 0.802 1.117 2.923 1.445
27 1.742 6.162 2.381 1.491 1.223 0.855 0.839 1.498 0.818 1.474 2.077 1.414
28 1.692 4.598 2.331 1.406 1.196 1.260 0.816 1.602 0.822 1.558 1.782 1.409
29 1.659 3.798 2.222 1.371 1.235 1.386 1.354 1.299 0.857 1.876 2.252 1.382
30 1.599 2.090 1.397 1.427 1.045 1.253 1.082 0.887 1.167 2.000 1.339
31 1.674 1.980 1.207 1.046 0.959 1.351 1.269
Average 3.563 5.241 2.600 1.869 1.386 1.015 0.956 1.060 0.808 1.045 1.799 2.107
Lowest 1.599 1.685 1.980 1.371 1.145 0.818 0.707 0.687 0.737 0.800 1.002 1.139
Highest 12.810 13.280 3.442 3.376 2.544 1.433 1.354 2.242 0.929 1.876 4.071 9.033
Monthly total
(million cu m) 9.54 13.13 6.97 4.84 3.71 2.63 2.56 2.84 2.09 2.80 4.66 5.64
Runoff (mm) 26 36 19 13 10 7 7 8 6 8 13 15
Rainfall (mm) 35 57 26 36 34 25 33 59 10 52 77 44
Statistics of monthly data for previous record (Sep 1966 to Dec 1995----incomplete or missing months total 0.2 years)
Mean Avg. 5.537 5.098 4.058 2.967 2.217 1.856 1.335 1.359 1.437 2.048 2.984 4.578
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. 40 34 30 21 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. 59 49 49 49 57 57 52 59 59 56 58 64
Low 20 9 14 7 11 9 12 15 15 7 28 20
High 103 138 92 100 141 132 111 110 118 127 129 148
Summary statistics Factors affecting runoff
1996
For 1996 For record As % of $ Flow influenced by groundwater abstraction
preceding 1996 pre-1996 and/or recharge.
Mean flow 1.942 2.947 66 $ Augmentation from effluent returns.
Lowest yearly mean 1.213 1976
Highest yearly mean 4.114 1993
Lowest monthly mean 0.808 Sep 0.343 Jul 1976
Highest monthly mean 5.241 Feb 16.200 Feb 1977
Lowest daily mean 0.687 20 Aug 0.234 26 Aug 1976
Highest daily mean 13.280 12 Feb 56.720 24 Jan 1988
10% exceedance 3.550 6.048 59
50% exceedance 1.334 1.656 81
95% exceedance 0.766 0.652 117
Annual total (million cu m) 61.41 93.00 66
Annual runoff (mm) 167 253 66
Annual rainfall (mm) 488 668 73
{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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