015006 Tay at Ballathie 1996
Measuring authority: SEPA Grid reference: 37 (NO) 147 367 Catchment area (sq km): 4587.1
First year: 1952 Level stn. (m OD): 26.20 Max alt. (m OD): 1214
Daily mean gauged discharges (cubic metres per second)
DAY JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1 116.000 78.680 136.100 86.570 166.000 145.400 40.580 33.670 37.210 61.830 270.600 268.900
2 139.300 75.040 158.600 87.900 157.400 140.100 42.720 36.520 38.830 58.240 293.900 314.000
3 129.900 72.080 204.800 93.530 150.600 146.200 44.280 35.580 37.520 95.780 447.500 263.700
4 187.600 67.280 177.300 99.120 139.400 152.600 48.650 34.080 38.990 172.300 514.700 283.500
5 266.900 69.110 126.700 100.600 140.300 153.300 46.470 33.470 37.470 144.600 441.000 251.600
6 380.100 67.120 115.800 110.900 137.700 145.100 44.260 31.900 36.330 129.000 709.500 227.100
7 371.000 65.120 109.600 102.200 143.200 137.500 42.700 30.690 35.430 121.000 468.300 179.100
8 541.000 68.880 94.480 99.720 140.200 123.900 41.630 30.600 34.350 105.300 359.900 296.600
9 648.000 125.600 91.540 131.000 132.300 118.700 41.190 31.120 32.960 89.210 346.000 290.600
10 433.800 211.100 82.350 221.600 121.100 119.800 40.530 35.260 32.280 74.890 311.300 271.900
11 380.200 236.600 115.100 243.800 112.600 124.100 39.880 39.350 31.760 72.960 286.200 242.400
12 448.100 237.800 224.000 223.500 111.000 136.900 40.860 36.000 30.650 164.500 241.200 220.100
13 463.200 212.500 161.900 156.300 108.600 117.400 39.840 34.660 29.510 185.900 208.900 176.900
14 440.800 182.200 140.100 151.800 101.500 106.300 38.300 32.130 28.750 168.800 207.400 144.400
15 380.800 331.700 128.300 169.000 94.210 78.520 36.540 32.580 28.360 341.000 196.500 137.800
16 316.400 489.300 130.200 229.300 92.690 66.900 36.450 31.660 27.680 280.100 177.500 146.200
17 282.000 368.300 138.500 367.400 97.930 65.270 35.670 30.790 26.920 217.100 167.000 139.100
18 264.000 340.700 135.000 413.300 92.160 59.000 34.290 30.270 26.080 197.700 156.200 206.600
19 246.400 268.800 123.800 333.400 102.700 56.080 34.080 29.940 24.980 232.000 157.000 220.200
20 243.200 232.300 118.100 289.700 108.000 51.280 33.590 32.250 24.000 192.200 155.300 176.100
21 198.500 211.400 118.400 303.000 109.200 50.460 33.290 33.150 23.600 191.400 145.500 158.000
22 192.200 188.200 117.400 335.400 138.200 47.430 34.140 33.280 23.300 160.000 132.100 135.800
23 222.000 174.200 106.500 322.100 153.700 45.350 39.190 39.850 23.070 152.200 118.100 125.900
24 170.900 175.900 108.100 261.100 132.000 43.980 40.410 41.150 24.300 170.600 117.100 115.600
25 156.600 157.200 108.600 231.300 131.300 43.600 35.580 43.220 24.000 291.600 118.100 105.000
26 136.800 141.900 98.320 217.900 130.400 41.860 34.910 41.440 27.520 333.200 119.800 98.680
27 119.400 134.600 91.200 208.500 125.000 40.850 34.080 44.680 31.630 469.900 118.200 87.820
28 114.400 126.400 94.080 191.900 120.800 41.240 33.460 41.830 36.130 447.500 115.000 72.210
29 105.700 129.300 92.050 182.900 122.800 41.110 32.900 40.150 85.240 356.300 128.400 68.450
30 89.460 85.200 174.100 127.900 40.360 32.970 38.810 65.460 297.600 175.400 65.210
31 82.280 80.970 157.000 33.340 37.440 297.900 60.950
Average 266.700 180.700 123.000 204.600 125.700 89.350 38.280 35.400 33.480 202.300 246.800 179.000
Lowest 82.280 65.120 80.970 86.570 92.160 40.360 32.900 29.940 23.070 58.240 115.000 60.950
Highest 648.000 489.300 224.000 413.300 166.000 153.300 48.650 44.680 85.240 469.900 709.500 314.000
Monthly total
(million cu m) 714.30 452.70 329.50 530.40 336.80 231.60 102.50 94.83 86.77 542.00 639.70 479.60
Runoff (mm) 156 99 72 116 73 50 22 21 19 118 139 105
Rainfall (mm) 142 126 63 110 70 51 52 65 64 223 171 70
Statistics of monthly data for previous record (Oct 1952 to Dec 1995)
Mean Avg. 257.300 220.500 226.000 159.100 119.100 79.520 67.620 86.360 122.800 191.900 213.100 241.600
flows: Low 92.900 52.560 69.380 75.210 45.500 42.080 31.390 14.700 40.660 39.690 73.190 110.500
(year) 1963 1963 1953 1974 1980 1957 1984 1955 1955 1972 1993 1989
High 563.200 661.000 551.600 306.900 321.100 190.400 129.600 286.100 283.900 390.500 407.700 491.400
(year) 1993 1990 1990 1993 1986 1966 1988 1985 1985 1982 1984 1954
Runoff: Avg. 150 117 132 90 70 45 39 50 69 112 120 141
Low 54 28 41 43 27 24 18 9 23 23 41 65
High 329 349 322 173 188 108 76 167 160 228 230 287
Rainfall: Avg. 170 112 132 75 92 82 92 107 131 153 143 166
Low 33 29 39 10 24 23 21 14 11 63 38 57
High 403 353 308 150 213 181 219 250 266 269 311 304
Summary statistics Factors affecting runoff
1996
For 1996 For record As % of $ Reservoir(s) in catchment.
preceding 1996 pre-1996 $ Regulation for HEP.
Mean flow 143.600 165.200 87 $ Abstraction for public water supplies.
Lowest yearly mean 107.300 1955 $ Flow reduced by industrial and/or
Highest yearly mean 215.100 1990 agricultural abstractions.
Lowest monthly mean 33.480 Sep 14.700 Aug 1955
Highest monthly mean 266.700 Jan 661.000 Feb 1990
Lowest daily mean 23.070 23 Sep 11.460 6 Aug 1955
Highest daily mean 709.500 6 Nov 1965.000 17 Jan 1993
10% exceedance 297.200 327.400 91
50% exceedance 120.000 130.000 92
95% exceedance 30.580 43.000 71
Annual total (million cu m) 4541.00 5213.00 87
Annual runoff (mm) 990 1137 87
Annual rainfall (mm) 1207 1455 83
{1961-90 rainfall average (mm) 1425}
Station and catchment description
Velocity-area station with cableway; 90m wide. The most d/s station on the Tay, records highest mean flow in UK. All
flows contained to date. C/m rated to above Qmed (approx. 4.7m). Some hydraulic analysis to est. highest floods. Since
end of 1957, 1980 sq.km (43%) controlled for HEP (providing potentially increased flood storage from mid-1990s); some
control prior to this. 73 sq.km controlled for water supply. Significant winter snow cover.
Catchment is mostly steep, comprising mountains and moorland; exceptions are lower valleys. Bedrock mainly metamorphics
and granite, but lower 20% (Isla Valley) is Old Red Sandstone. Approx. 60% is overlain by superficial deposits (mostly
Boulder clay). Landuse mainly rough grazing and forestry. Several large lochs in catchment.
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.