027002    Wharfe at Flint Mill Weir                                                                                1965


           Measuring authority: EA            Grid reference:     44    (SE) 422 473     Catchment area (sq km):    758.9
           First year: 1936                   Level stn. (m OD):   13.70                            Max alt. (m OD):  704



 Daily mean gauged discharges (cubic metres per second)


 
        DAY         JAN      FEB      MAR      APR      MAY      JUN      JUL      AUG      SEP      OCT      NOV      DEC

          1        32.280    8.382    6.711    9.373    9.515    5.493    5.040    9.401    8.070   92.030  133.400   12.830
          2        16.990    8.297    5.777    8.608    8.184    5.409    4.729   18.290    5.975   50.400   69.660   33.980
          3        11.920    6.768    5.493    7.759    7.929    4.871    3.200   33.980    5.833   29.730   28.010  173.000
          4         9.515    6.343    5.890    7.419    7.844    4.757    3.625   22.230    6.371   22.090   18.100   75.320
          5         8.693    6.570    6.116    7.532    9.090    3.172    4.587   37.100    7.589   17.760   14.220   60.600

          6         8.382   13.560    4.134    6.456    7.900    4.333    3.908   21.460    7.306   14.410   11.130   84.390
          7        11.840   10.530    4.701    7.589   12.120    5.097    3.879   16.680   13.250   12.600   10.050   45.870
          8        60.600    9.033    6.570    6.909   23.560    5.097    3.879   11.440   10.220   11.180   10.310   43.890
          9        39.360    8.070    7.900    7.108   32.850    6.230    3.370    9.118   11.920    9.798    9.684  227.100
         10        70.790    7.108    7.759   51.540   20.730    4.672    2.019    7.900   35.680    9.260    8.637  152.100

         11       108.500    6.230    7.249   23.620   13.650    4.531    2.801    6.230   20.390    8.269    8.665   59.180
         12        35.680    6.456    6.173   25.660    9.345    2.690    4.417    5.210   13.310    7.136   14.220   41.340
         13        37.380    5.692    5.550   24.890    8.099    3.370   10.510    5.040   10.790    7.221   11.330   52.950
         14        71.640    6.343    6.570   15.570    7.362    4.984   18.460    4.644    8.580    6.966    9.260   47.290
         15        41.340    6.230    8.778   26.620    6.230    4.078    9.968    5.154    7.362    6.768    8.467   43.330

         16        87.780    5.607   20.980   19.680    6.230    4.219    6.683    5.493   39.080    6.485    8.184   57.200
         17        82.400    5.692   11.470   32.570    7.447    4.417    4.333    6.032   22.510    5.692   12.860   49.270
         18        63.430    5.607    8.269   29.170    7.872    4.616    4.389    5.040   52.100    6.485   30.870  151.800
         19        32.000    5.918    8.693   23.080   12.350    8.495    4.984    4.163   19.000    5.777   28.600   52.950
         20        21.830    7.646    9.571   17.220    8.608    6.032    3.115    3.964   12.350    5.522   36.250   33.700

         21        15.720    6.570   11.810   13.820    7.589    6.286    3.087    8.665    9.571    6.371   24.440   25.490
         22        15.120    7.589   12.740   11.380    5.692    9.769    3.002   12.940    8.495    6.286   15.940   24.980
         23        13.110    7.985   45.310   10.080    5.692   11.270    2.645    7.306    7.759    4.446   19.510   92.880
         24        57.200    7.929   50.400    8.665    6.796   15.400    4.502    6.116    8.325    4.389   28.880   55.500
         25        25.400    7.249   38.790    7.759    6.966   22.260    4.757   18.040   19.540    5.635   66.830   37.950

         26        17.760    6.626   49.840    8.127    7.306   16.880    7.759   13.200  111.600    5.069   34.550   25.800
         27        16.030    5.097   62.300   10.420    7.023    9.430    7.108   10.650   39.080    4.729   22.710   19.770
         28        13.880    5.409   35.400   11.640    6.116    7.306   15.240    7.164   25.490    4.927   17.220   15.380
         29        12.350            20.130   20.050    4.842    6.230   71.360   10.190   52.390    5.154   17.420   16.170
         30        10.140            14.560   12.460    5.097    5.493   28.260    7.362   69.660   30.300   14.920   60.880
         31         9.033            11.240             5.890            12.230    6.513            48.990            51.820
 


 Average           34.130    7.162   16.350   15.760    9.546    6.896    8.640   11.180   22.320   14.900   24.810   62.090
 Lowest             8.382    5.097    4.134    6.456    4.842    2.690    2.019    3.964    5.833    4.389    8.184   12.830
 Highest          108.500   13.560   62.300   51.540   32.850   22.260   71.360   37.100  111.600   92.030  133.400  227.100

 Monthly total
  (million cu m)    91.42    17.33    43.79    40.85    25.57    17.88    23.14    29.96    57.85    39.91    64.31   166.30


 Runoff   (mm)      120       23       58       54       34       24       30       39       76       53       85      219  
 Rainfall (mm)      136       28       86       90       64       67      101       97      184       68      146      224  


 Statistics of monthly data for previous record  (Oct 1955 to Dec 1964)

 Mean      Avg.    25.830   21.790   17.470   13.780    9.364    5.400    9.506   14.250   12.570   14.240   20.000   25.370
 flows:    Low      4.472    2.974    6.741    5.197    3.911    1.545    3.601    1.795    1.419    6.597    6.876   10.230
           (year)    1963     1963     1961     1957     1960     1957     1959     1959     1959     1955     1958     1963
           High    39.260   47.220   36.400   22.280   17.780   14.450   16.440   41.340   22.270   25.440   51.090   40.190
           (year)    1961     1958     1963     1962     1958     1958     1963     1956     1956     1958     1963     1959

 Runoff:   Avg.      91       70       62       47       33       18       34       50       43       50       68       90  
           Low       16        9       24       18       14        5       13        6        5       23       23       36  
           High     139      151      128       76       63       49       58      146       76       90      174      142  

 Rainfall: Avg.     104       77       67       71       64       70       95      108       88       96       94      123  
           Low       41       20       28       10       25       33       35       18        8       46       33       41  
           High     165      178      127      130      122      140      185      226      135      165      211      203  


 
 Summary statistics                                                           Factors affecting runoff
                                                                    1965
                                   For 1965       For record        As % of   $ Reservoir(s) in catchment.
                                                  preceding 1965    pre-1965  $ Abstraction for public water supplies.
 Mean flow                       19.610          15.780                 124   $ Flow reduced by industrial and/or
 Lowest yearly mean                              12.390        1964             agricultural abstractions.
 Highest yearly mean                             19.290        1958           $ Augmentation from surface water and/or
 Lowest monthly mean              6.896    Jun    1.419    Sep 1959             groundwater.
 Highest monthly mean            62.090    Dec   51.090    Nov 1963
 Lowest daily mean                2.019 10 Jul    0.425 23 Jun 1957
 Highest daily mean             227.100  9 Dec  233.600  4 Dec 1960

 10% exceedance                  50.100          38.470                 130
 50% exceedance                   9.303           8.334                 112
 95% exceedance                   4.157           2.150                 193
 Annual total (million cu m)     618.40          498.00                 124
 Annual runoff (mm)               815             656                   124
 Annual rainfall (mm)            1291            1057                   122
         {1961-90 rainfall average (mm)          1161} 


 Station and catchment description

 
  Broad-crested masonry weir 47m wide; c/m cableway originally 1.5km u/s then moved to new ultrasonic station at Tadcaster
  in 1990. Insensitive at low flows. Does not drown at high flows, though small amount of bypassing on the right bank.
  Level data: 1936-1955. Recalibration (from 1965) completed but flows reprocessed from 1982 only. Pre-1965 data less
  reliable. Mill race opened in early 1990s (not rated) so flows not reliable. Regulation effect of headwater reservoirs
  evident at low flows. Small net export of water (inc. Bradford supply).
  Mixed geology of moderate permeability - mainly Carboniferous Limestone, grits and Coal Measures with over 40%
  superficial deposits. Predominantly mixed rural catchment, 60% grassland, with moorland headwaters.


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