1898.] on Bringing Water to Birmingham from Wales. 693 



north of Bewdley, where the pressure in thepijDes will be about 24.0 lbs. 

 on the square inch. At G3J miles it is just north of Wolverley, and 

 at 68 close to Hagley, reaching the intended Frankley reservoir at 

 73 miles Si chains. 



In addition to the two railways above mentioned the aqueduct 

 crosses the Shrewsbury and Hereford Hail way at 42 miles 10 chains, 

 the Severn Valley Railway at 58 miles 54 chains, the Stafford and 

 Worcester Canal at 62 miles 70 chains, and the Halesowen and 

 Bromsgrove Railway at 72 miles 5 chains. In its course it also 

 crosses the rivers Rea and Stour, and the Teme a third time. 



There are altogether — 



IS^ miles of tunnel ; 



23 miles of cut and cover ; and 



37 J miles of iron and steel pipes crossing 



valleys under pressure. 



Total 73J miles. 



The meaning of " cut and cover " is that the aqueduct is laid in 

 ground approximately parallel to and slightly higher than the hy- 

 draulic gradient line, so that an open trench maybe cut, the aqueduct 

 built in it, and the ground filled in and restored over it to its original 

 condition^ In tunnel and cut and cover the structure consists of blue 

 brick lining on a concrete backing so far as the invert and side wall 

 are concerned, the arch being of concrete only. 



Diagram No. 10 shows the cut and cover conduit in construction, 

 and Diagram No. 11 the aqueduct as built across narrow valleys. 



This conduit is laid almost throughout with a fall of 1 in 4000, or 

 about 16 inches in a mile, the exception being in the long tunnels, 

 which have slightly better gradients. It will carry, running some- 

 thing under full, 75 million gallons a day, and the first instalment of 

 27 million gallons a day will flow about 3 feet deep and with a sjiced 

 of 150 feet a minute, taking about 44 hours in its passage from 

 the Elan to Birmingham. In crossing valleys below the hydraulic 

 gradient line the aqueduct will consist at first of two 42-inch cast- 

 iron or steel pipes, with a fall of 3 feet in a mile, or 1 in 1760. As 

 the demand for water increases, a third, fourth, fifth and sixth jDij^e of 

 similar size will be laid. 



The service reservoir at Frankley is to be divided into two equal 

 parts, each holding 100 million gallons. The surface water area will 

 be 25 acres, and the depth 30 feet. The side walls will be of con- 

 crete faced with blue brickwork, a skin of asphalt coming between 

 them and being laid also on the concrete floor. Below this reservoir 

 will be built a series of filter-beds, sufficient at all times to efficiently 

 filter all the water that is required. From a pure water tank below 

 the filters the gravitation mains will start into the district, and from 

 it will be pumped such water as is wanted for a high fringe of 

 sparsely populated country too high to be commanded by gravita- 

 tion. 



Vol. XV. (No. 92.) 2 z 



