027002    Wharfe at Flint Mill Weir                                                                                1963


           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         5.295    4.163    2.577   18.940    7.957    3.540   49.560    2.645   13.900   14.410    9.911   15.070
          2         5.578    2.707    2.078   19.480    9.458    3.483   57.200    2.178   14.020   21.070    9.061   14.300
          3         5.578    3.228    2.526   13.990    7.306    3.143   51.250    1.968   14.500   54.090    8.297   13.560
          4         5.862    4.134    3.653   11.840    7.221    3.256   28.880    2.662   12.540   38.230    7.136   11.610
          5         5.437    3.143   40.490   12.600    5.805    4.389   51.820    9.203   10.280   33.700    7.702    9.260

          6         5.295    3.002  188.900   33.700    8.070    3.653   32.000   13.820    8.014   25.290   16.080    8.070
          7         5.663    2.973   82.690   24.520    6.456    3.030   29.730    6.853    6.853   30.580   15.350    8.184
          8         5.267    3.058   49.560   16.990    5.918    3.228   19.030    7.985   12.380   23.760   17.420    8.070
          9         5.352    2.639   59.180   12.150    5.692    2.803   14.580    7.617   38.510   31.150   25.540    7.646
         10         4.587    2.818   82.690   10.340    6.570    2.801   12.260    7.476   25.600   17.640   70.790    6.343

         11         4.021    3.681   48.420   10.220   11.180    2.297   11.750   12.600   12.660   13.930   52.670    5.522
         12         3.625    3.087   27.210   11.530    9.996    2.356   10.340   10.050    9.061   11.550   87.220    6.230
         13         3.710    2.888   19.600    9.911    9.458    3.511    8.863   21.830    7.702   10.310   60.880    6.570
         14         3.993    3.002   44.180   45.870   10.450    2.917    7.193   10.530    5.692   10.110   48.710    4.729
         15         3.455    3.087   45.020   88.630    8.495    2.005    7.532    7.193    5.239    8.835   72.770    5.267

         16         4.304    2.557   34.260   33.410    8.325    2.186   23.480    5.720    6.570   19.200   32.000    7.759
         17         4.078    2.653   35.400   32.280    7.249    3.568   13.080    8.778    5.522   13.250   33.700    7.532
         18         4.163    3.313   41.630   54.940    6.088    2.735   11.160    7.985    5.522    9.996  154.600    7.221
         19         3.058    2.860   28.600   28.600    6.286    3.002   10.220    7.306    5.182    7.759   90.900    6.286
         20         3.030    2.818   18.290   20.020    7.136    3.653    8.467    4.955    4.814    7.815   53.800    5.012

         21         4.531    2.781   13.680   22.170   31.430    3.483    7.561    5.607    2.792    8.297  129.100    3.993
         22         3.228    2.750   10.650   19.370   20.700    3.936    6.626    5.975    3.370    7.957  115.500    4.248
         23         3.540    2.299    8.920   17.530   11.980    4.927    5.748    6.060    5.125   10.340   62.860    4.927
         24         3.455    2.475    8.297   12.150    9.486    4.134    5.267   17.440    4.502   15.940   68.810    3.964
         25         3.511    3.115   71.080   10.450    8.495   22.200    4.899   14.950    6.485   10.820   68.810    9.175

         26         3.568    2.682   38.510    8.920    6.881   35.680    4.842   21.830   84.390    7.702  103.900   14.360
         27         3.738    2.619   20.760    7.759    6.739   16.340    3.143   40.210   27.100    6.683   39.640   10.390
         28         5.210    2.733   18.290    7.419    6.145   17.440    3.200   25.090   15.660    6.824   26.680   10.620
         29         5.833            20.980    7.759    5.550   41.910    4.163   12.660   33.410    5.862   24.100   11.040
         30         5.805            33.980    7.221    5.097   38.230    3.002    9.628   23.450    5.550   18.720   21.720
         31         4.871            26.250             4.701             2.815   25.290             5.748            58.330
 


 Average            4.472    2.974   36.400   21.020    8.785    8.328   16.440   11.100   14.360   15.950   51.090   10.230
 Lowest             3.030    2.299    2.078    7.221    4.701    2.005    2.815    1.968    2.792    5.550    7.136    3.964
 Highest            5.862    4.163  188.900   88.630   31.430   41.910   57.200   40.210   84.390   54.090  154.600   58.330

 Monthly total
  (million cu m)    11.98     7.19    97.49    54.49    23.53    21.59    44.03    29.73    37.23    42.72   132.40    27.39


 Runoff   (mm)       16        9      128       72       31       28       58       39       49       56      174       36  
 Rainfall (mm)       41       41      112       97       56      140       74      127       89       84      211       41  


 Statistics of monthly data for previous record  (Oct 1955 to Dec 1962)

 Mean      Avg.    30.920   26.150   13.980   13.160    8.977    4.919    8.357   15.900   13.190   14.870   17.050   26.540
 flows:    Low     24.320    7.996    6.741    5.197    3.911    1.545    3.601    1.795    1.419    6.597    6.876   16.850
           (year)    1956     1959     1961     1957     1960     1957     1959     1959     1959     1955     1958     1962
           High    39.260   47.220   22.520   22.280   17.780   14.450   14.000   41.340   22.270   25.440   45.900   40.190
           (year)    1961     1958     1957     1962     1958     1958     1960     1956     1956     1958     1960     1959

 Runoff:   Avg.     109       84       49       45       32       17       29       56       45       52       58       94  
           Low       86       25       24       18       14        5       13        6        5       23       23       59  
           High     139      151       79       76       63       49       49      146       76       90      157      142  

 Rainfall: Avg.     119       86       54       67       64       61       97      111       92      103       83      132  
           Low       77       20       28       10       25       33       35       18        8       46       33       84  
           High     165      178       86      130      122      112      185      226      135      165      198      203  


 
 Summary statistics                                                           Factors affecting runoff
                                                                    1963
                                   For 1963       For record        As % of   $ Reservoir(s) in catchment.
                                                  preceding 1963    pre-1963  $ Abstraction for public water supplies.
 Mean flow                       16.800          16.140                 104   $ Flow reduced by industrial and/or
 Lowest yearly mean                              12.470        1959             agricultural abstractions.
 Highest yearly mean                             19.290        1958           $ Augmentation from surface water and/or
 Lowest monthly mean              2.974    Feb    1.419    Sep 1959             groundwater.
 Highest monthly mean            51.090    Nov   47.220    Feb 1958
 Lowest daily mean                1.968  3 Aug    0.425 23 Jun 1957
 Highest daily mean             188.900  6 Mar  233.600  4 Dec 1960

 10% exceedance                  40.760          39.370                 104
 50% exceedance                   8.157           8.650                  94
 95% exceedance                   2.702           2.004                 135
 Annual total (million cu m)     529.80          509.30                 104
 Annual runoff (mm)               698             671                   104
 Annual rainfall (mm)            1113            1069                   104
         {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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