027002    Wharfe at Flint Mill Weir                                                                                1967


           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        27.990   37.320   47.320    9.506    6.071   14.160    6.626   13.320    8.240   31.180   33.290   11.640
          2        21.600   44.780   45.730   25.230    6.544   13.130    5.924    8.906   13.970   92.560   43.600    9.948
          3        16.480   32.420   31.680   23.210    6.595   10.290    6.213    7.150   33.960  100.400   28.060    9.158
          4        13.960   21.830   22.860   14.540   22.420    9.180    6.510   32.940   38.330   83.710   24.900    9.350
          5        12.600   16.450   18.420   10.970   16.800    9.172    5.893   27.920   88.980   32.480  112.500   10.340

          6        11.230   13.820   15.880    9.362   34.660   11.470    5.392   13.150   62.860   21.060   63.270   12.370
          7        10.690   12.330   13.570    8.948   29.370   11.320    5.309   10.920   30.760   54.880   34.040   10.150
          8        10.120   11.260   12.640   14.280   25.340    9.786    4.553   10.090   19.960   75.200   26.750    8.475
          9         9.464   10.400   23.250   27.880   23.630    8.730    4.086   66.330   15.440  148.700   26.560    7.614
         10         9.277    9.871   38.820   16.330   15.310    7.456    4.284   41.960   13.050   68.470   24.040    7.266

         11         9.713    9.132   31.920   11.630   12.740    6.924    4.466   30.590   11.530   35.130   47.300    7.841
         12         9.934    8.976   32.560   10.400   26.640    7.130    4.474   28.900   10.250   25.950   32.940    9.135
         13        10.050    8.761   23.190    9.373   25.200    6.969    4.449   24.250    9.285   27.160   21.680    9.560
         14         9.837    8.399   22.390    8.741   28.990    6.796   14.480   65.090    8.569   55.180   19.260    9.093
         15         9.512    8.051   21.860    8.303   90.230    6.635   11.150   47.410    7.654   66.330   17.300    9.090

         16         9.090    9.008   18.590    8.107   33.840    6.349    7.742   24.910    6.295  101.400   16.810   20.700
         17         8.617   20.430   18.040    7.796   24.290    5.380    6.708   26.080    6.657  214.600   14.140   11.440
         18         8.863   20.710   17.230    7.416   18.640    4.848   10.680  137.100    6.734   57.070   12.490    9.229
         19        18.440   34.030   12.480    7.133   22.530    5.233    9.132   97.130    7.025   49.480   10.670    8.288
         20        16.180   35.780   10.790    7.088   28.300    5.547    7.849   37.420    6.870   35.900   10.200    7.677

         21        30.010   25.090   10.420    7.326   23.840    5.760    6.417   21.540    6.677   26.890   10.410    7.790
         22        29.780   37.670    9.812    7.068   37.620    6.148    5.046   16.260    6.060   20.690   10.240   16.350
         23        45.070  104.500   10.070    6.892   24.570    7.985    4.497   13.260    5.230   16.970    9.849  111.900
         24        36.270   34.320   13.130    7.832   33.240    8.390    4.460   11.690    4.998   25.710    9.367   47.790
         25        41.700   25.790   10.410   14.620   39.650   37.690    4.369   11.590    6.060   22.650    9.359   38.070

         26        38.730   32.970   22.110   10.140   25.830   29.270    4.890    8.543   29.000   23.250   11.990   24.650
         27        26.600   80.990   16.170    8.371   27.720   13.960    5.278    7.699   25.170   40.200    9.172   23.660
         28        28.920  130.500   13.680    7.702   49.280    9.384    8.455    7.779   12.110   51.220   21.580   30.460
         29        21.030            12.140    6.578   30.870    8.809    5.714    7.759   11.000   26.200   20.110   20.120
         30        25.080            11.740    6.179   21.460    8.495   25.580    7.272   61.740   19.030   13.950   16.310
         31        24.310            11.820            17.060            44.730    7.631            24.330            18.720
 


 Average           19.390   30.200   20.020   10.970   26.750   10.080    8.237   28.150   19.150   54.000   24.860   17.880
 Lowest             8.617    8.051    9.812    6.179    6.071    4.848    4.086    7.150    4.998   16.970    9.172    7.266
 Highest           45.070  130.500   47.320   27.880   90.230   37.690   44.730  137.100   88.980  214.600  112.500  111.900

 Monthly total
  (million cu m)    51.94    73.06    53.63    28.42    71.65    26.13    22.06    75.39    49.63   144.60    64.44    47.88


 Runoff   (mm)       68       96       71       37       94       34       29       99       65      191       85       63  
 Rainfall (mm)       68      114       72       52      181       65       90      183      125      225       89       72  


 Statistics of monthly data for previous record  (Oct 1955 to Dec 1966)

 Mean      Avg.    26.170   23.440   17.400   15.370   10.410    6.217    9.266   14.240   13.850   14.730   20.610   29.800
 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   54.590   36.400   29.330   20.720   14.450   16.440   41.340   22.320   25.440   51.090   62.090
           (year)    1961     1966     1963     1966     1966     1958     1963     1956     1965     1958     1963     1965

 Runoff:   Avg.      92       75       61       53       37       21       33       50       47       52       70      105  
           Low       16        9       24       18       14        5       13        6        5       23       23       36  
           High     139      174      128      100       73       49       58      146       76       90      174      219  

 Rainfall: Avg.     104       83       68       77       69       73       94      110       95       95      100      133  
           Low       41       20       28       10       25       33       35       18        8       46       33       41  
           High     165      194      127      130      122      140      185      226      184      165      211      224  


 
 Summary statistics                                                           Factors affecting runoff
                                                                    1967
                                   For 1967       For record        As % of   $ Reservoir(s) in catchment.
                                                  preceding 1967    pre-1967  $ Abstraction for public water supplies.
 Mean flow                       22.480          16.770                 134   $ Flow reduced by industrial and/or
 Lowest yearly mean                              12.390        1964             agricultural abstractions.
 Highest yearly mean                             23.300        1966           $ Augmentation from surface water and/or
 Lowest monthly mean              8.237    Jul    1.419    Sep 1959             groundwater.
 Highest monthly mean            54.000    Oct   62.090    Dec 1965
 Lowest daily mean                4.086  9 Jul    0.425 23 Jun 1957
 Highest daily mean             214.600 17 Oct  233.600  4 Dec 1960

 10% exceedance                  44.080          40.200                 110
 50% exceedance                  13.810           8.972                 154
 95% exceedance                   5.474           2.287                 239
 Annual total (million cu m)     708.90          529.20                 134
 Annual runoff (mm)               934             697                   134
 Annual rainfall (mm)            1336            1101                   121
         {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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