053008 Avon at Great Somerford 1996
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 6.161 2.501 3.732 4.008 2.056 0.811 0.489 0.338 0.427 0.388 0.663 3.396
2 6.282 2.347 3.499 3.748 1.931 0.807 0.498 0.333 0.422 0.386 0.900 5.842
3 5.715 2.284 3.350 3.462 1.824 0.786 0.485 0.317 0.414 0.328 2.223 4.979
4 5.567 2.258 3.142 3.347 1.764 0.748 0.474 0.323 0.403 0.314 1.731 4.044
5 6.387 2.303 2.912 3.144 1.689 0.735 0.487 0.322 0.397 0.302 2.078 3.745
6 7.761 2.148 2.806 3.007 1.580 0.747 0.479 0.319 0.392 0.301 3.581 3.478
7 10.010 2.126 2.884 2.848 1.491 0.731 0.437 0.338 0.383 0.304 2.802 3.274
8 13.670 5.019 2.800 2.656 1.457 0.698 0.421 0.359 0.362 0.329 2.504 3.104
9 9.813 5.686 2.615 2.631 1.406 0.692 0.403 0.410 0.369 0.348 2.402 2.929
10 9.553 5.216 2.665 2.513 1.312 0.688 0.384 0.536 0.377 0.339 2.225 2.751
11 12.990 14.440 3.327 3.797 1.274 0.632 0.378 0.468 0.375 0.339 2.048 2.623
12 11.130 8.211 3.000 3.634 1.206 0.620 0.368 0.357 0.366 0.346 1.797 2.509
13 9.049 6.355 2.690 3.041 1.143 0.579 0.374 0.321 0.366 0.352 1.717 2.339
14 7.490 5.769 2.890 2.679 1.097 0.567 0.373 0.361 0.359 0.366 1.638 2.175
15 7.154 5.310 2.858 2.600 1.065 0.558 0.364 0.397 0.348 0.366 1.592 2.158
16 6.546 4.917 2.728 2.429 1.066 0.549 0.368 0.400 0.352 0.365 2.094 2.119
17 5.886 4.889 2.686 2.402 1.113 0.540 0.356 0.388 0.346 0.413 1.929 2.595
18 5.435 4.202 2.598 2.322 1.219 0.528 0.352 0.377 0.335 0.405 3.676 3.997
19 4.986 3.884 2.628 2.242 1.108 0.533 0.355 0.376 0.330 0.441 4.615 3.408
20 4.401 3.649 3.248 2.160 1.021 0.535 0.343 0.376 0.331 0.431 3.652 3.035
21 4.134 3.623 3.965 2.459 1.103 0.517 0.335 0.405 0.326 0.419 3.356 2.687
22 3.997 3.743 4.895 4.253 1.071 0.508 0.338 0.684 0.316 0.381 3.113 2.594
23 3.993 9.478 4.116 3.242 1.403 0.505 0.327 0.588 0.314 0.365 4.463 2.415
24 3.736 8.823 9.165 2.763 1.188 0.500 0.325 0.577 0.330 0.357 5.057 2.261
25 3.412 6.781 13.200 2.507 1.121 0.496 0.318 0.510 0.332 0.435 3.981 2.144
26 3.198 5.354 7.624 2.396 1.031 0.503 0.313 0.549 0.321 0.667 3.657 2.102
27 3.090 4.553 6.396 2.286 0.960 0.511 0.323 0.506 0.315 0.700 3.410 1.999
28 2.984 4.246 5.660 2.222 0.962 0.505 0.366 0.483 0.442 0.731 4.772 1.941
29 2.808 3.889 5.012 2.276 0.929 0.498 0.375 0.459 0.508 0.703 4.252 1.872
30 2.665 4.773 2.229 0.873 0.484 0.360 0.427 0.420 0.711 3.742 1.743
31 2.567 4.253 0.809 0.341 0.425 0.635 1.655
Average 6.212 4.966 4.133 2.843 1.267 0.604 0.384 0.420 0.369 0.428 2.856 2.836
Lowest 2.567 2.126 2.598 2.160 0.809 0.484 0.313 0.317 0.314 0.301 0.663 1.655
Highest 13.670 14.440 13.200 4.253 2.056 0.811 0.498 0.684 0.508 0.731 5.057 5.842
Monthly total
(million cu m) 16.64 12.44 11.07 7.37 3.39 1.56 1.03 1.13 0.96 1.15 7.40 7.60
Runoff (mm) 55 41 37 24 11 5 3 4 3 4 24 25
Rainfall (mm) 56 66 61 51 47 17 34 81 39 69 102 33
Statistics of monthly data for previous record (Jan 1964 to Dec 1995)
Mean Avg. 7.111 6.379 4.722 3.050 2.223 1.517 0.973 0.738 0.917 2.039 3.818 6.249
flows: Low 1.493 1.545 1.077 1.055 0.518 0.327 0.185 0.153 0.235 0.263 0.314 0.984
(year) 1976 1976 1993 1976 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. 63 51 42 26 20 13 9 7 8 18 33 55
Low 13 13 10 9 5 3 2 1 2 2 3 9
High 112 110 91 54 78 45 55 33 40 56 92 141
Rainfall: Avg. 83 59 66 50 67 62 57 61 74 74 78 90
Low 12 6 17 5 7 6 10 3 23 6 33 19
High 152 145 151 107 159 144 127 139 172 169 173 176
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 2.268 3.299 69
Lowest yearly mean 1.344 1973
Highest yearly mean 4.235 1986
Lowest monthly mean 0.369 Sep 0.153 Aug 1976
Highest monthly mean 6.212 Jan 15.990 Dec 1965
Lowest daily mean 0.301 6 Oct 0.112 2 Sep 1976
Highest daily mean 14.440 11 Feb 61.350 11 Jul 1968
10% exceedance 5.118 8.073 63
50% exceedance 1.643 1.803 91
95% exceedance 0.327 0.331 99
Annual total (million cu m) 71.72 104.10 69
Annual runoff (mm) 237 344 69
Annual rainfall (mm) 656 821 80
{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.