30 ON THE REMOVAL OF BARS FROM 
brought about by the ia ie ‘Gaitinturbed action of the 
tidal and upland water scour. At the present time, the entrance 
the great curvature of the river at ce harbour, the effect of which, 
as is well-known, is to cause the currents to scour out deep holes 
at certain points, and to throw up banks and others, and there is 
no doubt that this action will necessitate a large amount of 
dredging to keep the harbour of uniform depth. 
In investigating how far the general principles set forth above, 
and illustrated by the works at the Tyne, Tees, and Liffey, may be 
applied in dealing with our rivers, it may be well to take the Rich- 
mond and Clarence Rivers as examples ; and, in dealing with these 
cases, to show how, with modifications to suit local circumstances, 
they may be generally applied to the other rivers along our coast. 
The Richmond River (plate No. 4) flows through one of the 
most fertile districts of the Colony, and is navigable for vessels of 
moderate size for some distance from the entrance ; but, as is 
about 6,000 feet. The North Creek joins the main river at nearly 
right angles, opposite the centre of the entrance, thus forming a 
somewhat complicated combination. The general tendency of the 
the heads, with the exception of a nurrow channel under the 
ead, and occasionally there is a second channel at the 
South Head, but this is not permanently navigable. 
In attempting to improve this entrance, the first thing to be 
conside: 
Pd 
is at what point should the entrance channel be fixed 5 
possible, 
, to act jointly upon our fixed sre on the bar. 
