Alnwick Hill Filter Beds, Cleaning Sand

Category

Library Item

Item no

30409

Title

Alnwick Hill filter beds, cleaning sand

Artist / maker

Bell, J. Munro

Date

1890

Size

9.0 x 14.5 cm

Type

Engraving

Location

Edinburgh and Scottish Collection

Bailie James Colston felt that the filters which served reservoirs were important enough to give an overview of their construction in his book 'Edinburgh and District Water Supply.' '..the ground was excavated...to the depth of 12.5 feet, and the bottoms and sides of the beds made perfectly water-tight by means of clay puddle. Over the bottom part of the bed there were placed three inches of carefully watched sand: and over that there was a layer of three inches of fine screened gravel. Passing down the centre, along the whole length of the beds is a drain of dry mason work to carry off the filtered water. Over the three inches of gravel already mentioned there is a bed of gravel of coarser quality from 1 foot 6 inches to 3 ft 6 inches in depth, the upper surface being formed in ridges and furrows. There is then a layer of 6 inches of fine gravel...then a layer of 6 inches of sea shells. Again there is a layer of coarse sand, and the whole is finished by another layer of 18 inches of the finest sand by means which the process of filtration is carried on. It need not be added that the filtering material requires to be most carefully washed before being put into its place: and the upper stratum requires to be perfectly cleaned', (p. 85 from the bound volume, 'The Edinburgh and District Water Supply, a historical sketch').
This image is an engraving of an original photograph by Alexander Leslie C.E.

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Landscape > Land > Hills

Landscape > Water > Reservoirs

Manufacturing Industry > Manufacturing facilities > Construction

Manufacturing Industry > Manufacturing facilities > Construction sites

People > Adults > Men

People > Industry > Construction workers

Places > Edinburgh areas > Liberton

Places > Scotland > Edinburgh

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