248 W. IT. Iludleston— Recent Wells in Dorset. 



Other Artesian Wells and Borings in Dorset. 



Messrs. Eldridge, Pope, & Co.'s well at Dorchester.' The operations 

 were conducted in 1880-1. The mouth of the well is on the north 

 side of the London and South-AVestern^Railway Station, and probably 

 about 250 feet above O.D, The total depth bored in this case was 

 597 feet, wholly in the Chalk. A well was dug for 70 feet and the 

 rest completed with 6 inch tubes. The water-level at the time work 

 was finished stood at 45 ft. 8 in. below the surface — hence this well is 

 ' sub-artesian ' like the one at Bovington. The yield obtained was 

 3,000 gallons per hour. The first indications of having struck a 

 supply of water appear to have occurred after the boring rod had 

 passed 467 feet. Hence, in this ease nearly 500 feet of Chalk was 

 pierced ere an adequate supply of water could be obtained. According 

 to Mr. Pope it is concluded that the base of the boring is 220 feet 

 above the Upper Greensand, which would give 817 feet for the 

 thickness of the Chalk at Dorchester. 



The history of artesian water supply at Wimborne (Fig. 5) is an 

 interesting one, for there the hydrostatic pressure, before the supplies 

 had been tapped so freely as in later years, was sufficient to raise the 

 water from the Chalk to the siirface and far above it. Forty years ago 

 (in 1867) a three-inch borehole was made at Ellis's brewery, where 

 the Chalk is said to have been reached at a depth of 97 feet. There 

 was such an uprise that the yard was flooded by a column of water of 

 considerable height. It is interesting to note that in this case the 

 water seems to have been obtained without sinking into the Chalk to 

 any depth. This brewery is situated in the Allen Valley flat and 

 about 60 feet above O.D. 



Bjr far the most important of the artesian wells at Wimborne 

 are the Wimborne Waterworks and the Bournemouth Waterworks. 

 These are situated at the north end of the town in the valley flat of 

 the Allen, close to each other and to Warford Bridge, at an elevation 

 of about 66 feet above O.D. As regards the Wimborne Waterworks, 

 Mr. Fletcher^ says that this boring was executed under his super- 

 intendence about twenty years ago. It is a 7^ inch bore, and until 

 the Bournemouth Well was sunk within 200 or 300 yards of it the 

 water rose in the tube-well 6 feet above the surface of the soil. This 

 well is situated on the south-east side of Warford Bridge, and the 

 following is the vertical section : — 



Thickness. Depth, 

 ft. in. ft. in. 



/ Peaty matter 6 0| 



Superficial | Sub-calcareous silt... ... ... ... ... 8 0:- 1.5 



( Valley gravel and sand-rock ... ... ... 1 ) 



/ Plastic and variegated clay ... ... ... 45 Q\ 



T> T T> J I Clays and sands sometimes imijregnated with f --a 



Beading Beds < ■^ -, ^. ^ " op n / '^ " 



° 1 pyritous salts ... ... ... ... ... 2b 0| 



V Flints of junction bed ... ... ... ... 4 0/ 



Chalk Chalk and flints 40 130 



1 For the particulars subjoined I am indebted to Mr, Alfred Pope and to 

 Messrs. Le Grand & Sutcliff. 



- I have to thank Mr. "Walter J. Fletcher, the County Surveyor, for much 

 valuable information in connection with the Wimborne wells. 



