page_title: Bonaly
section_title: Bonaly Reservoir
hierarchical_section_title: Bonaly / Bonaly Reservoir
caption_attribution_description: English: Bonaly Reservoir. The reservoir and a sample of the rough grazing that makes up the northern slopes of the Pentland Hills. This picture was taken less than 8km from Edinburgh Castle.
context_page_description: Bonaly is an area on the south-western outskirts of Edinburgh and the northern slopes of the Pentland Hills, lying within the Parish of Colinton. It is a mix of mainly post-war housing, woodland, pasture-land and heather moorland. Bonaly Burn has its sources in the hills above Bonaly and flows towards Oxgangs, where it becomes the Braid Burn. The Edinburgh City Bypass passes through Bonaly.
context_section_description: During the 19th century, the Edinburgh Water Company created several reservoirs in the Pentland Hills. Bonaly Reservoir was one of the first to be constructed, and had two purposes – to supply fresh drinking water to the city and to ensure a constant flow of water in lower watercourses by acting as a compensation reservoir.
  The reservoir is situated in a shelf on the north-west slope of Capelaw Hill. At 340m above sea level, it is one of the highest bodies of water in the Pentlands and has an unusually small natural water catchment area. The natural catchment has been augmented by catch-drains laid out across the hillside to the south-west, which act to divert spring and rain-water into the reservoir.
  The present Bonaly Reservoir was created on the site of an existing body of water – known as Bonaly Pools – by the damming of the Dean Burn with a stone-faced earthwork in 1853. It has a capacity of 218 million litres and is 7.5m deep when full. The remains of an earlier earthwork dam are located to the north of the current dam.
  This site of the present reservoir has been a source of fresh water for Edinburgh since 1761. A wooden pipeline was constructed from Bonaly Pools to Swanston, from where it was piped into the city. The wooden pipes were replaced by iron pipes towards the end of the 18th century. This pipeline was re-discovered during a RCAHMS survey of adjacent military training areas in 2005.
  Unlike most of the Pentland reservoirs, Bonaly is not managed by Scottish Water and no longer forms part of the water supply chain. It is owned and managed by the City of Edinburgh Council. Proposals exist to manage the water levels in the reservoir so that feeding and breeding opportunities for wildlife are maximised.
caption: Bonaly Reservoir
exif: {}