OFFICE OF SURVEYOR GENERAL
ESTIMATE OF THE EXPENSE NECESSARY TO BE INCURRED
Culverts &C.
PLAN OR DESCRIPTION.
The services undertaken upon this authority comprise general repairs and cleansing of culverts, drains, and catchpits under the charge of Inspector.
L. The cleansing of silt, stones, or material washed into the drains from the hills or from adjoining newly made roads, all of which suffer considerably until the surface becomes consolidated. This is especially true in dry seasons when the absence of water to bind the soft surface material means that after a three or four months' drought, a shower of rain falling at the rate of from half an inch to an inch per hour acts upon the sun-hardened surface exposed by cutting for building areas, naturally causing a considerable amount of silt.
This is reduced year by year as our works of drainage and surface stability are brought to their ultimate limit in one district, viz., the hillwards, as it has done in one district bounded by Robinson Road.
The works arranged for the prevention of stones entering drains (washed down the slopes by excessive velocity of the currents) have been effective during the last two seasons.
Approved, W. G. Mercer
(signed)
Octing Governor.
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