Geograph - photograph every grid square

This is one of a group of buildings, all now derelict, at the eastern side of NS4176 : Garshake Water Works; see that item for the main description of the water works.

The subject of the present photograph is not the taller building on the left, which is shown separately in NS4176 : Garshake Water Works: eastern building, but, rather, the one which takes up the rest of the foreground.

The main description of the water works (see the link in the first paragraph, above) cites a booklet which describes the inauguration of a pressure filter station here on the 21st of November, 1964. That pressure filter station is shown in the present photograph. (Immediately to the south were the wash water settlement tanks and the sludge drying bed.)

What remains of the building is U-shaped, since its filter room has been demolished; this accounts for the gap, on the right, between the two arms of the building. This is also apparent in another view of the same building: NS4176 : Garshake Water Works: Pressure Filter Station.

The filter room contained ten filter shells; their detailed construction and operation are explained in the booklet, in which the building as a whole is summarised as follows: "The Filter Station is of single storey construction and of modern appearance and contains a filter room with pipework basement, chemical stores and workshop areas, an office and laboratory and cloakroom accommodation ... the plant installation has a capacity of 1.125 million gallons per day, although until the housing areas are fully developed, part of the outflow will go to the existing storage reservoirs which are adjacent to the slow sand filter beds".

(Two of those reservoirs are the storage tanks, 90 and 45 feet in diameter, that are shown in NS4176 : Water storage tank and NS4176 : Water storage tank; the tanks themselves date from the nineteenth century, but their conspicuous dome covers were added shortly after the pressure filter station was built.)

The quoted excerpt also alludes to the development of housing in the high-lying parts of the Burgh of Dumbarton; this was the main reason why the new filter pressure station was needed.

Of the filter shells, it was noted that "the normal filtration rate is of the order of 90-100 gallons per hour per square foot of sand area. A branch pipe from the base of each shell conveys the flow to the filter water outlet main, and this main is bifurcated in turn to enable the water to be fed to NS4176 : Maryland Tank or, should this high level tank be full, to the 45 foot diameter storage tank or either of the other two storage reservoirs in the slow sand bed areas".