388 REPORTS ON THE STATE OF SCIENCE, ETC. 
place the settlement of compensation water on a proper footing and save 
considerable outlay on works. 
(6) The narrow valleys where the river is confined during floods are 
distinctly suitable for flow measurements, especially if a pool reach is 
available or can be made by inserting a sunken weir. Such sites are well 
adapted to accurate current meter gaugings. 
(c) The open valleys and lake areas are eminently suitable for water level 
records which, coupled with flow measurements at the outlet from such 
areas, will give valuable information as to storage effect. 
(6) and (c) will provide the principal flow measurement sites before the 
river emerges on the final lowlands. ‘The continuous water level records 
may, in many cases, be maintained by canal undertakings or electrical 
power stations or river water supply stations or other works. 
(d) Lowland plains: The flow in these lowland plains may be difficult 
to correlate with water levels as the water slopes will vary considerably 
with rising and falling floods and general backing-up effects. It would 
seem more advisable to concentrate on measurement of channels, and so 
forth, and on the installation of well-situated water level stations. 
Improvements in storage capacity and, consequently, in water slope in 
these lowland areas appear to be the key to improved drainage ; and the 
fen areas are an example of what has been effected in this way. With 
increased capacity in the lowlands and with control of tidal inflow, quicker 
run-off through higher reaches may be aimed at without causing floods 
in the lowlands. 
The difficulties of control of tidal inflow on a navigable river are present 
in the problem of the Thames floods below Teddington. 
5. THE ROUTINE OF SURFACE WATER MEASUREMENTS (EXCLUDING 
RAINFALL). 
Section (3) deals with the land survey side of areas, lakes, reservoirs, 
waterways, river channels, etc. ‘These may be termed static measurements 
and the records of such measurements will lie, firstly, on the 6-in. or other 
scale Ordnance maps and, secondly, on such detailed plans and tables, etc., 
as may be necessary. 
The routine of water measurements covers the following procedure :— 
(a) Observational work on water levels. 
(b) Checking and filing of observational work. 
(c) Compiling the records on standard lines. 
(d) Analysis and publication. 
The measurement of river flow at gauging sites does not come under 
this routine work (see Memorandum F). The table of flows resulting 
from this measurement is used for the conversion of water levels into 
flows, at stages (b) or (c) of the above routine. 
It is, however, quite likely that at some gauging sites the continuous 
measurement of maximum velocity will be additional to the water level 
measurements. ‘There is need of a suitable recorder for this purpose. 
(a) Observational work: Water levels —Gauge posts read once or twice 
daily or occasionally. 
Automatic water level gauges. Charts changed weekly. Clock winding. 
Checking of graphs with gauge post readings. 
Returns to filing office with any comments. 
