053008 Avon at Great Somerford 1998
Measuring authority: EA Grid reference: 31 (ST) 966 832 Catchment area (sq km): 303.0
First year: 1964 Level stn. (m OD): 57.60 Max alt. (m OD): 207
Daily mean gauged discharges (cubic metres per second)
DAY JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1 13.590 3.399 1.204 2.250 4.345 1.241 1.422 0.750 0.439 1.123 20.920 2.804
2 20.130 3.101 1.554 2.325 3.994 2.374 1.224 0.739 0.497 0.976 20.110 2.704
3 25.290 2.946 8.937 4.048 3.737 1.931 1.111 0.695 0.546 0.907 22.990 2.605
4 26.870 2.818 8.328 6.159 3.524 1.551 1.039 0.669 0.587 0.869 12.320 2.499
5 24.030 2.704 4.906 4.835 3.394 1.288 0.986 0.639 0.693 0.841 9.881 2.365
6 21.930 2.643 18.710 4.238 3.210 1.197 0.949 0.604 0.563 0.825 8.400 2.255
7 19.970 2.604 19.690 4.499 3.007 1.103 0.904 0.558 0.550 0.793 7.496 2.168
8 15.230 2.476 11.370 5.185 2.839 1.168 0.809 0.546 0.573 0.761 13.000 2.558
9 12.650 2.376 8.979 15.190 2.671 1.617 0.794 0.527 0.606 0.743 17.530 2.724
10 10.940 2.270 8.000 8.087 2.634 1.528 0.814 0.516 0.578 0.739 10.900 3.432
11 9.670 2.202 7.284 6.382 2.630 1.301 0.829 0.501 0.560 0.715 9.509 3.651
12 8.529 2.090 6.216 5.554 2.449 1.111 0.944 0.483 0.697 0.688 11.260 4.527
13 8.623 2.033 5.660 5.181 2.340 1.662 0.822 0.488 0.640 0.698 9.062 4.653
14 8.896 1.947 5.264 6.905 2.186 2.812 0.755 0.507 0.580 0.712 8.816 3.820
15 8.286 1.906 4.856 7.175 2.080 2.017 0.688 0.516 0.543 0.694 7.397 5.372
16 7.511 1.800 4.464 5.817 1.897 1.497 0.696 0.503 0.514 0.778 6.478 5.108
17 6.965 1.721 4.090 4.767 1.766 1.305 0.678 0.508 0.504 1.779 5.946 4.278
18 16.760 1.686 3.732 4.330 1.782 1.390 0.640 0.529 0.510 1.168 5.474 6.778
19 10.640 1.632 3.400 4.408 1.592 1.360 0.616 0.500 0.502 0.961 5.020 6.826
20 8.360 1.624 3.172 4.337 1.650 1.113 0.607 0.472 0.482 0.922 4.571 4.929
21 7.771 1.642 2.975 3.906 1.535 1.002 0.573 0.482 0.473 1.083 4.166 4.484
22 7.195 1.528 2.784 3.870 1.467 0.938 0.570 0.483 0.471 2.177 3.961 4.377
23 6.420 1.462 2.740 5.619 1.412 0.921 0.585 0.524 0.466 6.234 3.674 7.173
24 5.884 1.362 2.666 6.380 1.375 0.920 0.568 0.517 0.463 17.340 3.659 6.483
25 5.395 1.345 3.035 11.170 1.423 0.953 0.556 0.474 0.477 11.750 3.444 15.810
26 4.969 1.314 3.428 8.630 1.361 1.571 0.568 0.472 0.723 6.924 3.281 29.200
27 4.537 1.317 3.076 6.826 1.583 3.435 0.547 0.467 1.329 11.560 3.127 17.910
28 4.289 1.274 2.757 5.856 1.357 1.762 0.534 0.461 1.118 11.810 3.397 12.600
29 4.108 2.538 5.239 1.202 1.563 0.545 0.454 1.012 8.188 3.184 10.700
30 3.912 2.448 4.685 1.122 2.127 0.547 0.450 1.248 6.826 2.937 9.062
31 3.490 2.338 1.081 0.563 0.417 19.590 8.116
Average 11.060 2.044 5.503 5.795 2.214 1.525 0.757 0.531 0.632 3.909 8.397 6.515
Lowest 3.490 1.274 1.204 2.250 1.081 0.920 0.534 0.417 0.439 0.688 2.937 2.168
Highest 26.870 3.399 19.690 15.190 4.345 3.435 1.422 0.750 1.329 19.590 22.990 29.200
Monthly total
(million cu m) 29.62 4.94 14.74 15.02 5.93 3.95 2.03 1.42 1.64 10.47 21.77 17.45
Runoff (mm) 98 16 49 50 20 13 7 5 5 35 72 58
Rainfall (mm) 104 15 88 108 27 126 30 35 106 145 70 92
Statistics of monthly data for previous record (Jan 1964 to Dec 1997)
Mean Avg. 6.905 6.305 4.654 2.981 2.156 1.464 0.940 0.724 0.904 1.960 3.785 6.181
flows: Low 1.023 1.545 1.077 0.922 0.518 0.327 0.185 0.153 0.235 0.263 0.314 0.984
(year) 1997 1976 1993 1997 1990 1976 1976 1976 1990 1990 1964 1964
High 12.700 13.750 10.260 6.354 8.850 5.220 6.271 3.778 4.697 6.329 10.750 15.990
(year) 1995 1977 1981 1966 1983 1971 1968 1985 1974 1967 1992 1965
Runoff: Avg. 61 51 41 26 19 13 8 6 8 17 32 55
Low 9 13 10 8 5 3 2 1 2 2 3 9
High 112 110 91 54 78 45 55 33 40 56 92 141
Rainfall: Avg. 80 61 65 50 67 62 56 63 72 74 79 89
Low 9 6 17 5 7 6 10 3 22 6 33 19
High 152 145 151 107 159 144 127 139 172 169 173 176
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 4.090 3.234 126
Lowest yearly mean 1.344 1973
Highest yearly mean 4.235 1986
Lowest monthly mean 0.531 Aug 0.153 Aug 1976
Highest monthly mean 11.060 Jan 15.990 Dec 1965
Lowest daily mean 0.417 31 Aug 0.112 2 Sep 1976
Highest daily mean 29.200 26 Dec 61.350 11 Jul 1968
10% exceedance 9.698 7.941 122
50% exceedance 2.291 1.749 131
95% exceedance 0.490 0.332 148
Annual total (million cu m) 129.00 102.10 126
Annual runoff (mm) 426 337 126
Annual rainfall (mm) 946 818 116
{1961-90 rainfall average (mm) 804}
Station and catchment description
Compound Crump profile weir - low flow crest between two flanking sections. Situated 90m d/s of Great Somerford road
bridge. Full range station. All except extreme flows (e.g. Jul 1968) contained. Flows augmented by gw scheme in
catchment.
Geology: mainly Oolitic L'st with lb tributaries draining off clays. Land use: predominantly rural.
In line with Natural Environment Research Council policy, the provision of data from the National River Flow Archive confers only a right to use the data. Ownership of the data, or the associated Intellectual Property Rights, will not normally be transferred. Data received from the NRFA must not be sold, or passed on to any third party. Reproduction is authorised, except for commercial purposes, provided the sources is acknowledged.
Through the use of quality control procedures every effort is made to maintain and improve the quality of data. However, NERC, the Environment Agency, the Scottish Environment Protection Agency and the Rivers Agency accepts no liability for any loss or damage, cost or claims arising directly or indirectly their use.