History of the Huddersfield Water Supplies
By T. W. Woodhead

CHAPTER VI - UNDERGROUND WATER SUPPLIES.

BORE HOLES

The water stored in our impounding reservoirs, both for industrial purposes and domestic supplies, is supplemented by tapping underground sources.

As in selecting the site of a reservoir, a knowledge of the geology of the district is important. For a satisfactory supply of underground water three conditions are essential:-

1. The rock must be porous, or sufficiently jointed, to act as a reservoir, and the yield may be greater where the beds are faulted or sharply folded.
2. The outcrop of the beds must cover a sufficient area and be able to absorb a sufficiently high rainfall.
3. The beds must dip in the required direction and conduct the water absorbed.

The principle depends upon the hydrostatic pressure of the water percolating through the porous and jointed inclined rock, and forcing its way upward through the bore-hole to the highest level of the water-containing strata.

Underground supplies have been resorted to locally for a long period, both for domestic and industrial purposes, with varying results both in yield and quality of water obtained. Geologists are agreed that it is not possible to say from a knowledge of surface geology whether the rock at a particular site will yield water.

The formation which is greatest importance for the supply of water in the Huddersfield District, is the Millstone Grit Series. These rocks outcrop over a large area to the west and south-west, where the rainfall is high (50-60 inches) and the beds dip gently towards the town. Unfortunately these grits have a low porosity and unless the beds are faulted or freely jointed and the joints of useful size and continuity, the yield is low and uncertain. Some of the grits examined by Professor P.F. Kendall have a porosity of only two or three per cent., “no more than sufficient to wet the surfaces of the particles,” this low porosity militates against their usefulness as sources of supply. If, however, in a boring, cores are met with which include joints with rusty surfaces, as at Wessenden Head, which suggest access of oxidizing surface waters, a fair flow may be obtained. To supply the needs of a single factory bore-holes, though not always successful, often prove a valuable asset and many have been sunk in the district for this purpose.

Our local supplies depend largely on the vertical jointing of the rocks which permit a fairly free passage of water, and in the shales along the bedding planes, but deep bore-holes have been sunk into the massive Kinderscout Grits, which gave a very poor supply.

Nevertheless good supplies of soft water have been obtained from the Rough Rock, Huddersfield White Rocks and the Middle Grits. The lowest bed tapped is the Lower Kinderscout Grit. A good supply was obtained from the latter beds at the Isle of Skye bore-hole, but gave a smaller yield at Deanhead.

It frequently happens that a bore-hole starting in the Coal Measures and descending to the Millstone Grits, water of a very different character is met with even within a few feet of strata. In the Coal Measures a very hard water may be met with, while in the grits below the water is usually very soft. A remarkable feature is the large amount of Sodium carbonate these grits sometimes contain, e.g., water from the Huddersfield White Rock in the boring at Rock Mills, Brockholes. This reduces the hardness below the figure which the amount of Calcium Carbonate in the rocks might be expected to produce. This is the bed to which Blackmoorfoot bore-hole descends, and into which the adits are driven. An analysis is given below of the bore-hole at Rock Mills, and for comparison one from the Lower Coal Measures at the New Peace Pit, Leeds Road. Much water is available locally from beds at the latter horizon, but it is extremely hard and ferruginous and is quite unsuitable for any purpose except cooling.

Occasionally a bore-hole has been deepened with a view to increasing the supply when the result has been a failure. In some cases an abundant supply of water of an unsuitable quality has been encountered.

Although the water obtained from bore-holes is often a valuable asset, we must recognize that these deep-seated sources in the Millstone Grits of the Central Pennines do not yield a supply sufficient to meet the needs of a large industrial area, and we have to depend for our main supply upon impounding schemes located in our neighbouring moorlands where as we have seen, nature has placed such a liberal supply at our disposal. All the water obtained the boreholes for domestic use in the area of supply of the Huddersfield Corporation, is passed through filters before entering the mains.

Members of the Geological Survey and especially Dr. D.A. Wray, have ever been ready to place their expert knowledge at the disposal of the Waterworks Committee and their assistance in relation to borings has been greatly appreciated.

As an illustration of the nature of the deposits through which our local borings may pass, the following details are given of the boring at Messrs. W.T. Johnson & Sons, Bankfield Mills, Moldgreen, Huddersfield. For further details of the fossils found in this boring reference should be made to the Survey Memoir “The Country Around Huddersfield and Halifax,” pages 189-191.

A still deeper borehole is that of Messrs. T. and H. Blamires, Ltd., Leeds Road, Huddersfield. Beginning in the superficial gravels, it enters the Lower Coal Measures above the level of the Hard Bed Coal, then passing through the Millstone Grit Series, descends to the Lower Kinderscout Grist to a depth of 1,550 feet. Details of both these bore-holes are illustrated in the Tolson Memorial Museum. Alongside each section are fossils from the bore-holes, characteristic of the successive marine and freshwater bands, together with their significance in the various deposits.

The rocks revealed in these borings show a fairly constant succession of beds, e.g., grit, fireclay, coal marine band, shale, or mudstone and flagstone. These cycles of deposit represent a series of oscillations and breaks in the depression of the ground and successive sedimentation.

Subsidence occurred in a series of jerks and as a result of each movement an invasion of the sea occurred, leading to the formation of a bed with marine fossils. Sedimentation then overtook subsidence, leading eventually to the formation of a sandstone and finally to coarse gritstone ; subsequently followed, in several instances a land surface on which grew plants which formed the Coal Seams.

Marine bands, sometimes only a few inches thick, crowded with remains of marine animals, are found at intervals throughout the Millstone Grits, and two or three extend into the lowest part of the Lower Coal Measures.

The marine bands are remarkable persistent, and the fossil goniatites in them show several mutations in ascending the series and as one form usually predominates in a band, goniatites are of the greatest interest and importance, both in themselves and as aids to stratigraphy.

Bore-holes have been sunk by the Huddersfield Waterworks authority at four sites:- Brow Grains, Wessenden Head, Blackmoorfoot and Deanhead.

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