AFFOEESTATION OF CATCHMENT AEEAS 95 



considerable number of small farmers, and greatly reduced 

 the number of sheep on the area, thus lessening the risk 

 of contamination of the streams. The Corporation also 

 adopted a scheme of afforestation in 1904, with the view 

 of keeping the water pure. By 1908 about 408 acres 

 had been planted with 1,640,000 trees. Smoke arising 

 from the large manufacturing towns around Eivington caused 

 some difficulty, as certain species failed to grow or ceased to 

 thrive after a time. Beech and ash, however, were a success ; 

 sycamore throve moderately ; and Corsican pine and Douglas 

 fir did well in certain situations. Larch proved a failure. 



The growth of trees on the Eivington area has not been 

 entirely successful, as some years ago a plague of voles 

 did great damage. The smoke nuisance has gradually 

 increased, and for the last four or five years forestry 

 operations have been confined to filling up vacancies. The 

 total area of the plantations, however, amounted on 30th 

 June 1916 to 1300 acres, situated between 450 and 

 1100 feet elevation. Beech, spruce, sycamore, ash, alder, 

 Corsican pine, and oak were the main species planted, 

 3,404,866 young trees being used. 



The Liverpool Corporation have not entered into any 

 agreement with the Government in regard to the afforesta- 

 tion of the Eivington area. The subject was discussed in 

 1912, when a joint scheme for planting the Lancashire 

 gathering grounds of the Liverpool and Bolton Corporations 

 was proposed ; but the matter dropped. 



Manchester owns two catchment areas, that of Lake 

 Thirlmere in Cumberland, and the Longdendale Valley in 

 Cheshire and Derbyshire. 



The natural catchment area of Lake Thirlmere is 7400 

 acres, but water from a further area of 3600 acres was 

 diverted into the lake, so that the total catchment area is 

 11,000 acres, all owned by the Manchester Corporation. 

 This ranges in elevation from 533 feet, the natural level of 

 the lake, up to 3118 feet, the summit of Helvellyn. The 

 geological formation is Lower Silurian, the rock being near 



