INLAND WATER SURVEY 413 
water for public supply. The powers granted to the two Conservancy 
Boards are greater than are given in the Rivers Pollution Prevention Acts. 
Reference should also be made to a clause in the Land Drainage Act, 
1930, which provides that a provisional order constituting for a catchment 
area or combination of catchment areas a joint committee or other body 
having any of the powers of a sanitary authority under the Rivers Pollution 
Act, 1876, may be made under Section 14 of the Local Government Act, 
1888, by the Minister of Health of his own motion and without any 
application by the Council of any of the counties concerned. No joint 
committee or similar body has so far been set up under this particular clause. 
From the preceding paragraphs, it is clear that the administration of 
the Rivers Pollution Prevention Acts is vested in local sanitary authorities, 
joint committees, fishery boards and other bodies on which the local 
authorities are represented. In dealing with problems of pollution and of 
fisheries, these bodies are definitely interested in river flow data, river 
levels, compensation water and similar matters. It is suggested that these 
bodies should in general be in a position to arrange for systematic measure- 
ments of river flow and river level, the results of which might then be sent 
to some central office for collection, correlation and, possibly, publication. 
Some of the local organisations mentioned are obtaining data on river flow, 
but in most instances no systematic observations have yet been made. 
Matin MEMORANDUM FE, 
UNDERGROUND WATER. 
By BERNARD SMITH. 
I. SUGGESTIONS AS TO OBSERVATIONS AND MEASUREMENTS NECESSARY. 
In any organisation dealing with inland water resources accurate 
observations should be taken on the occurrence, amount and quality of the 
water stored underground in suitable permeable strata, and upon that 
which issues in the form of springs and seepages. 
In some districts percolating water is stored in rocks of open porous 
texture such as certain sandstones, which form natural reservoirs lying 
between, or faulted against, impermeable strata in such a way that a definite 
measurable water-table is established ; while in others it is stored mainly 
in systems of connected fissures and bedding planes (such as those in 
chalk), also with a fairly definite measurable water-table. In other cases, 
again, it occurs in more sporadic fashion, either (a) in thin, and at times 
discontinuous, permeable strata—as when thin beds of limestone or sand- 
stone alternate with shales, or sandy lenticles occur in glacial clays—or 
(6) in irregular fissures from which isolated springs may arise, but in which 
no definite water-table can be determined—as in slates, granites, etc. 
Beneath cover, and down dip, many of these rocks in their subterranean 
extension will yield water under artesian head when tapped by bores or wells. 
In all cases the thickness, geological character and structures of the 
water-bearing rocks require careful study. 
Water-tables.—It is essential that any measurable water-tables occurring 
in strata that fall within a definite drainage-basin should be studied in 
detail, and contours or cross-sections drawn to show their levels at three, 
four or more different periods of the year. For this purpose it is desirable 
to have standing water levels measured in a carefully selected series of 
wells, that tap water in the bed or beds undergoing observation, within as 
