WATER CATCHMENT AREAS 239 
be kept. The grazing of cattle is not allowed within 100 
yards of the streams. The water is filtered. 
Cardiff obtains its supply of domestic water at present 
from a gathering ground of 4000 acres, at the head of the 
Taff Fawr River in Brecknockshire. There are two reservoirs, 
Beacons reservoir at 1340 feet and Cantreff reservoir at 
1073 feet elevation, the highest point on the area being 
Brecon Beacons, 2910 feet. The Council have purchased 
728 acres of this area, and have planted 25 acres with trees 
up to February 1918. “Prof. Fraser Story advised the 
Council regarding afforestation ; and a deputation was sent 
to interview the Development Commissioners, but little help 
or encouragement was given at the time.” Upon the parts 
privately owned, there are no buildings except a house 
belonging to the Corporation, and steps are taken to prevent 
any contamination. Adjacent to the preceding gathering 
ground is the lower catchment area of Taff Fawr, on which 
the Llwynon reservoir is being built at 850 feet elevation ; 
but the work of construction was stopped in November 1915. 
This area comprises 6000 acres, between 850 and 2000 
feet elevation, and of it 1248 acres are owned by the 
Corporation. The average rainfall varies from 76°96 inches 
at the Beacons reservoir to 60°31 inches at the Llwynon 
reservoir. The water is filtered. 
Cardiff has also another gathering ground, with two 
reservoirs at Llanishen and Lisvane, about four miles north 
of the city, comprising 2000 acres mainly over limestone, 
mostly arable land with some pasture and woods, extending 
on the north to the Caerphilly hills and on the east to Cefn 
Mably Park. Recently considerable building has taken 
place of a suburban character. The Corporation own no 
part of this area, the water of which has not been utilised 
for domestic purposes for many years past. Owing to the 
non-completion of the Llwynon reservoir, the Lisvane gather- 
ing ground may shortly be used to supplement the water 
from the Taff Fawr; and this would entail steps being taken 
to prevent contamination of the water of the several streams. 
