015006 Tay at Ballathie 1985
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
1 199.400 410.100 129.200 318.500 104.300 79.430 58.440 159.900 432.500 356.300 95.480 483.600
2 179.500 405.800 122.500 300.600 102.600 71.110 55.690 206.900 347.000 335.900 102.500 416.000
3 180.900 295.100 123.300 333.300 88.650 72.440 54.470 187.200 353.000 372.200 101.400 650.400
4 159.700 321.600 177.100 278.300 80.210 58.790 56.420 167.000 301.300 525.200 139.200 449.500
5 124.100 275.500 155.000 387.300 75.200 57.040 76.160 154.900 316.300 505.300 210.100 412.300
6 121.000 242.600 144.200 387.700 76.020 58.410 88.040 136.800 263.400 492.900 183.400 372.900
7 127.500 219.200 178.300 305.100 65.290 55.320 65.280 143.100 240.100 454.000 202.100 341.200
8 132.400 170.000 165.100 251.100 66.120 53.630 61.340 124.100 217.800 412.500 232.200 304.900
9 128.200 138.500 151.200 223.200 63.380 52.610 58.450 154.100 214.400 351.400 344.700 290.300
10 128.000 128.500 173.200 189.600 65.920 49.390 58.650 159.000 186.000 323.600 206.000 248.400
11 123.300 137.300 142.700 193.200 61.260 49.950 59.770 141.500 167.600 316.000 189.600 237.600
12 108.400 134.400 139.600 167.600 58.340 55.520 69.970 171.300 145.700 286.100 171.400 443.500
13 100.000 127.500 140.200 169.200 70.340 56.500 84.380 166.600 149.900 255.800 174.000 363.900
14 107.000 115.200 146.400 163.700 70.280 53.030 69.850 330.500 175.900 241.900 174.300 294.800
15 102.400 109.000 147.000 157.500 71.010 50.430 69.420 441.000 187.700 228.200 169.800 279.600
16 101.100 92.670 109.700 162.500 71.450 46.160 84.890 512.100 195.000 214.800 176.700 267.800
17 110.300 91.490 104.500 151.700 62.200 44.830 97.380 384.300 201.300 205.800 155.700 317.100
18 116.700 89.730 106.600 134.900 65.310 46.310 112.900 332.000 205.600 189.500 161.000 305.600
19 104.700 99.270 95.660 141.500 68.100 45.560 111.200 334.600 294.600 164.500 145.600 306.600
20 95.280 97.340 93.210 128.200 65.000 46.610 121.200 375.700 257.200 151.600 129.900 459.600
21 109.200 109.500 90.500 120.700 61.370 48.680 116.000 374.600 511.100 133.500 122.600 790.800
22 118.600 113.400 89.840 116.300 58.910 171.300 107.200 312.000 461.200 125.100 117.800 540.300
23 104.600 253.400 86.200 117.000 63.540 115.000 103.800 342.500 572.700 120.600 101.200 453.500
24 102.000 272.000 98.020 116.100 140.700 101.500 115.600 569.500 419.300 112.200 92.950 418.700
25 93.880 192.700 99.590 107.100 114.100 110.100 125.200 427.200 343.300 99.530 93.410 363.000
26 85.310 159.300 90.140 105.600 155.400 81.670 248.200 328.200 319.800 86.330 101.500 316.800
27 84.200 135.400 83.070 99.220 119.700 83.850 493.700 369.300 286.800 83.650 91.000 264.600
28 89.960 127.900 78.440 98.050 111.500 73.630 328.700 384.500 257.500 88.590 81.150 240.100
29 98.520 78.430 107.000 100.600 66.360 332.400 302.800 239.200 84.040 84.690 220.300
30 136.000 84.440 110.500 88.290 61.220 247.900 330.000 252.700 78.780 130.600 194.500
31 330.700 162.200 83.460 175.100 344.800 78.430 201.100
Average 125.900 180.900 122.100 188.100 82.210 67.210 126.100 286.100 283.900 241.100 149.400 362.900
Lowest 84.200 89.730 78.430 98.050 58.340 44.830 54.470 124.100 145.700 78.430 81.150 194.500
Highest 330.700 410.100 178.300 387.700 155.400 171.300 493.700 569.500 572.700 525.200 344.700 790.800
Monthly total
(million cu m) 337.20 437.60 327.10 487.50 220.20 174.20 337.60 766.20 735.80 645.80 387.20 971.90
Runoff (mm) 74 95 71 106 48 38 74 167 160 141 84 212
Rainfall (mm) 91 40 83 106 79 87 169 250 179 91 131 219
Statistics of monthly data for previous record (Oct 1952 to Dec 1984)
Mean Avg. 238.600 203.500 200.300 143.400 118.300 81.070 65.520 79.610 117.600 186.100 214.600 240.700
flows: Low 92.900 52.560 69.380 75.210 45.500 42.080 31.390 14.700 40.660 39.690 89.160 112.800
(year) 1963 1963 1953 1974 1980 1957 1984 1955 1955 1972 1972 1952
High 515.800 353.700 424.800 231.200 230.800 190.400 111.500 161.100 207.800 390.500 407.700 491.400
(year) 1974 1962 1967 1960 1983 1966 1970 1956 1982 1982 1984 1954
Runoff: Avg. 139 108 117 81 69 46 38 46 66 109 121 141
Low 54 28 41 43 27 24 18 9 23 23 50 66
High 301 187 248 131 135 108 65 94 117 228 230 287
Rainfall: Avg. 156 103 116 71 97 84 91 102 133 151 147 165
Low 33 31 39 10 26 49 21 14 11 63 38 64
High 393 182 224 150 200 181 144 184 266 269 311 271
Summary statistics Factors affecting runoff
1985
For 1985 For record As % of $ Reservoir(s) in catchment.
preceding 1985 pre-1985 $ Regulation for HEP.
Mean flow 184.800 157.300 117 $ Abstraction for public water supplies.
Lowest yearly mean 107.300 1955 $ Flow reduced by industrial and/or
Highest yearly mean 207.900 1954 agricultural abstractions.
Lowest monthly mean 67.210 Jun 14.700 Aug 1955
Highest monthly mean 362.900 Dec 515.800 Jan 1974
Lowest daily mean 44.830 17 Jun 11.460 6 Aug 1955
Highest daily mean 790.800 21 Dec 1223.000 27 Nov 1954
10% exceedance 369.600 304.600 121
50% exceedance 139.000 127.400 109
95% exceedance 56.800 42.550 133
Annual total (million cu m) 5828.00 4964.00 117
Annual runoff (mm) 1270 1082 117
Annual rainfall (mm) 1525 1416 108
{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.