Environmental Engineering Reference
In-Depth Information
Millstone grit
Fissure
Low storage
0·35-0·45
Permo-Triassic sandstone
Intergranular
High storage
0·70-0·80
Coal measures
Intergranular
Low storage
0·40-0·55
Cretaceous sands and silts
Intergranular
Low storage
0·35-0·50
Lias clays
Impermeable
Low storage at shallow
depth
0·40-0·70
Old red sandstone
Impermeable
Low storage at shallow
depth
0·46-0·54
Silurian/Ordovician shales/slates
Impermeable
Low storage at shallow
depth
0·30-0·50
Metamorphic and igneous
Impermeable
Low storage at shallow
depth
0·30-0·50
Oxford, Wealden and London
clay
Impermeable No storage
0·14-0·45
Source
: After Institute of Hydrology (1980).
Figure 14.7
The general character of storm hydrographs (a)
and the annual hydrograph (b) of the river Thames at
Teddington.
Source: Data from the DoE Water Data Unit (1983).
