WATER SUPPLY OF BIRMINGHAM.
For many years it had been determined to obtain for the great iron manufacturing city of Birmingham, Warwickshire, the metropolis of the English Midlands, a supply of water that should be not only adequate to the wants of the city, but also wholesome in quality. Birmingham itself being situated on the ridge of the great watershed of the Midlands, there was no source of supply to be found in the neighborhood or even within a circumference of many miles, wherefore, the corporation determined to bring the water from the Elan valley in Wales, a distance of eighty miles, at an estimated cost of $30,000,000.
The municipality bought the control of all the water that was to be obtained from the watershed referred to—that of the Elan, the Clarewen, and their tributaries about Caban Coch, comprising over seventy square miles in Cardiganshire and Radnorshire. The amount of water thus obtainable is estimated at a minimum of 100,000.000 gallons a day which will be collected in a reservoir to be built at C^ban Coch—the lowest in the series. From this reservoir will be discharged every day into the Elan river 27,000.000 gallons of ‘ compensation water—”the remainder being carried to Birmingham by an aqueduct from the reservoir, which will have a storage capacity of over 7,000,000 gallons, to a service resetvoir at Franklin, with a capacity of 200.000,000 gallons and situated within six miles of the centre of Birmingham. This aqueduct will be seventy-five miles long, with a fall of 170 feet gradient—although Birmingham is situated at a very high level above the sea. Six reservoirs wi l be built, three in the valley of each river. Those on the Elan are the Caban, occupying the lower part of the Clarewen (clear water) valley: Ben-y-gareg, with storage capacity of 1.300,000 gallons, and the Craig Coch—the highest in the Elan valley—with a capacity of 2,000,000 gallons. These three reservoirs will furnish the first instalment of water —provision being made for further extension as the necessity arises. The aqueduct will be partly in ‘cut and cover,” partly in tunnel, and partly in syphon—passing near Knighton to the south of Rhayader, where a long tunnel is beingdriven.
The acreage drained for the use of these reservoirs is about 22,000 acres, while the river Clarewen drains about 27,000, and will have three reservoirs upon it when these are called for. The act of Parliment secured to the corporation of Birmingham 45,562 acres, including all manorial rights, whereby all pollution of the waters and its sources may be prevented. Of that tract over 40,000 acres are composed of open, uncultivated, mountain pasture, with about one sheep (and the Welsh sheep are verv small) to the acre and a total population within the area scheduled of between 175 and 130 persons. Thedanger of pollution is, therefore, practically reduced to nothing. The water is very pure, free from nitrates and nitrites—and its total solids amounting to only five grains to the gallon. The water is also very free from hardness—in itself no small recommendation from an economical standpoint, considering how many boilers, etc., it will have to supply in Birmingham and its suburbs.