The Longdendale Chain of reservoirs was built to supply water from the River Etherow to the urban areas of Greater Manchester, while maintaining a constant flow into the river. The upper reservoirs supply the drinking water, while Vale House and Bottoms are compensation reservoirs which guarantee the flow of water to water-powered mills downstream. The 3ft gauge railway line was built to assist with the construction of the reservoirs. It was electrified as early as 1904 and operated by a small four-wheeled locomotive. In 1949, the locomotive was replaced with a diesel, then the wiring was removed a few years later. The line closed in 1968.
The Chew Valley Tramroad was laid in the Chew Valley, above Saddleworth, to transport 42,318 cubic yards of clay for an inner core for the reservoir dam, completed in 1912. At 1,600 feet (490 m) above sea level, it was the highest reservoir constructed in England. The tramroad is gone but the route forms the Oldham Way long-distance footpath.