INLAND WATER SURVEY 397 
Run-off.— 
(a) (i) The total run-off from the area. 
(ii) The monthly run-off from the area. 
(iii) The total run-off for specific dry or wet periods. 
(iv) Daily and weekly run-off could be obtained from the records when 
necessary. 
As regards peak rates of flow, these can in most cases only be ascertained 
approximately, few reservoirs having instruments recording the rise and 
fall of water level throughout the entire depth. 
(6) (i) The annual run-off (overflow water and compensation) passing 
into the stream below the lowest reservoir. 
(ii) The monthly run-off (overflow water and compensation) passing 
into the stream below the lowest reservoir. 
(iii) The run-off for specific dry or wet periods. 
(iv) Daily and weekly figures of a similar nature could be furnished 
when necessary. 
Most undertakings reasonably organised aim at statistics in respect of 
(a) (i), (ii) and (iii), and could furnish also (8) (i), (ii) and (iii). 
It would not serve any immediately useful purpose to work out (a) (iv) 
and (8) (iv) for the whole year. In most cases the adjustments are laborious 
and would only be undertaken where the results would be valuable. 
It is very desirable that peak rates of flow should be ascertained in the 
cases of the maximum floods in each year, and undertakings should provide 
the necessary recording instruments. 
SuB-MEmMoRANDuM D (2). 
CATCHMENT BOARDS. 
By J. C. A. ROSEVEARE, 
The forty-six Catchment Boards set up by the Ministry of Agriculture 
and Fisheries, under the Land Drainage Act, 1930, have jurisdiction over 
39,000 square miles, which is 67 per cent. of the area of England and Wales. 
Many of these statutory areas consist of a number of separate river-basins 
amalgamated for convenience in administration. 
It is unfortunate for the purpose of water survey that these authorities 
do not cover the whole of England and Wales, but the Minister has power 
to set up additional Catchment Boards if necessary. The boards are 
representative of all the interests in the catchment areas, two-thirds of the 
members being nominated by county councils and county borough councils, 
and one-third representing lowland areas in the catchment area. 
It will be admitted that a catchment basin is the proper unit for water 
survey as regards rainfall and river flow, but this is not entirely so when 
considering underground water, which may, in special cases, travel from 
one catchment basin to another. 
In order to design works in the most economical way, Catchment Boards 
should know the maximum and minimum flows in their rivers, and should 
keep continuous records of the rainfall and the flow resulting therefrom. 
It is suggested that these Catchment Boards should undertake the water 
survey of their respective areas. From information received from a few 
Catchment Boards, it appears that some are already taking steps to this end. 
