398 REPORTS ON THE STATE OF SCIENCE, ETC. 
APPENDIX D (2) (a). 
Paper BY J. C. A. ROSEVEARE. 
On ‘ LAND DRAINAGE IN ENGLAND AND WALES,’ PRESENTED TO THE 
INSTITUTION OF WATER ENGINEERS, AT THEIR WINTER MEETING, ON 
DECEMBER 2, 1932. 
The paper, and the discussion which followed, appeared in the winter 
number of Water and Water Engineering. 
The paper describes the formation and constitution of the forty-six 
Catchment Boards under the Land Drainage Act of 1930, and gives 
information as to the areas, length of ‘ main river,’ rateable value and 
other details of the catchment areas. 
. The paper and the discussion both indicate the lack of information as to 
river flows, the crudeness of the estimates of flood flows, and the need for 
accurate gauging. 
APPENDIX D (2) (8). 
THAMES CONSERVANCY. 
(REPLY TO QUESTIONNAIRE.) 
By G. J. GRIFFITHS. 
(1) The gaugings of the river Thames are made at Teddington Weir, 
which is at the seaward end of the Conservators’ jurisdiction. The river 
below Teddington Weir is tidal. ‘The measurements are made of the water 
passing over gauge crests and weir overfalls and through sluice openings. 
The water levels are recorded by continuous clock recorders at points 
some little distance upstream and down-stream of the weir. 
The formule from which the calculations are made were evolved some 
fifty years ago, and though they are not entirely in accordance with modern 
formule, they are retained in order that the results may be kept comparative 
with those of the past. The estimated flow has been checked from time 
to time by current meter observations at various magnitudes of discharge, 
and, on the whole, close agreement has been found between the calculated 
gaugings and the current meter observations. : 
(The formule employed are given in the original statement.) 
Current meter observations are taken at times for the purpose of ascertain- 
ing the flow at certain other parts of the river or of tributaries, particularly 
in periods of drought. 
See Appendix F (5). 
(2) Part of Teddington Weir is normal to the direction of the stream, and 
part is at an angle thereto. sea 
The tail-water side being tidal, there is a considerable variation in the 
‘fall’ from head to tail at the weir during the day. This differs from 
about 3 in. to some ro ft. in periods of low flow, and from about 1 ft. 3 in. 
to 2 ft. in times of high flood. 
The range of water levels at which flows have been calculated extend 
over some 6 ft. or 7 ft. on the headwater side of Teddington Weir, or over 
a range of 16:5 ft. on the tail-water side, the flows ranging from 33 cub. ft. 
to 37,000 cub. ft. per second. 
At some other weirs upstream of Teddington the range is from ro ft. to 
