The reservoir is fed by the streams which form the headwaters of the River Kent which rise 1.5 kilometres (0.93 mi) to the north in Hall Cove on the southern slopes of a mountainous ridge called High Street, which is named after the nearby Roman road.

It is also fed by Lingmell Gill, which drains the large corrie on the western side of Harter Fell beneath the Nan Bield Pass.

They employed the water engineer John Frederick Bateman to advise, and the Act of Parliament obtained in 1845 authorised five reservoirs.

Despite Bateman's preference for the reservoir at Skeggles Water, the millers opted to build that at Kentmere Head, which was completed in 1848, but cost a lot more than estimated.

However, there was public outcry, because the reservoir is in an area of natural beauty, and despite not needing the water, Croppers paid for engineering work to remedy the faults, resulting in a slightly lower maximum water level, and a wall being constructed along the top of the dam to prevent wave action causing the downstream face to erode and possibly fail.

Lime from a quarry located above Kentmere Hall was used to condition the soil, and field drains were added to make the land more suitable for agriculture.

However, these alterations to the landscape had unexpected consequences for the mill owners further downstream who relied on the steady flow of the River Kent to maintain their operations.

[6] By 1844 there were 15 mills on the Kent, three on the Sprint and five on the Mint, processing wool, gunpowder, bobbins, logwood, dyewood, paper, marble and iron.

[7] A total of ten mill owners and the mayor of Kendal formed a provisional committee, which resolved to build reservoirs in Kentmere and elsewhere, to maintain flows on the rivers.

[8] The committee lost no time in employing the eminent water engineer John Frederick Bateman to advise on the scheme, who in turn commissioned Job Bintley to survey the proposed sites in September and October 1844.

[9] Arguments against the scheme focused on the high cost, the fact that it would only be a benefit to a small number of mill owners, it would use up valuable agricultural land, and would cause desolation and loss of life if the dam burst.

Three separate dams would have been built, and this reservoir was favoured by Bateman, because he thought it would cost the least, and would provide a similar yield to Kentmere Head.

[17] Although Bateman does not appear to have been involved during the actual construction, his specification for building the dam has been preserved by James Cropper of Burneside Paper Mill.

The upstream face was covered in stone cladding, while the outlet pipe ran through the bottom of the dam with a valve house on the downstream side.

James Cropper & Company became the largest user when they opened a paper mill at Bowston in 1880, as they then owned a total fall of 51 feet (16 m).

In the 120 years since its construction, the clay core had consolidated, lowering its top to a point where water could soak through the fill above it, which might cause slippage of the downstream face of the dam.

[25] In 1995, having failed to interest either North West Water or the National Rivers Authority (NRA) in taking it over, they offered to give the reservoir to any new owner for free in return for their paying for repairs totalling £100,000 plus annual maintenance of over £2,000.

Croppers agreed to bring the next statutory inspection forward by two years, and assembled documentation on the reservoir, which revealed a succession of problems starting soon after its construction.

[27] Major issues included raising of the embankment due to settlement in 1852, 1861 and 1926, rebuilding of the bywash in 1864 after it failed, and lowering of the overflow weir by 1 foot (0.30 m) in 1926.

Although Croppers did not use the water from the reservoir, they decided to carry out repairs, which consisted of grouting of the foundations and crest of the dam; insertion of a liner into the scour pipe and a CCTV survey to prove its effectiveness; building a wall along the crest of the dam to prevent wave action damaging the downstream slope; removing silt from the tunnel through the downstream embankment; and grouting the spillway.

The liner consisted of a 16-inch (400 mm) diameter HDPE pipe manufactured by Stewarts and Lloyds Plastic, and butt welded on site.

[31] Once all issues had been remedied, the reservoir was filled slowly, using the outlet valve to prevent water levels rising too fast.