August Wilhelm Karlson obtained a diploma as a civil engineer from the University of Stockholm, Sweden, in 1879. He subsequently worked as an engineer for the French government railways (1880-1886), on the Panama Canal (1886-1890), and for the municipality of Bordeaux, France (1890-1892). He was a member of the Technical Institute of Sweden, the Sanitary Institute, and the Royal Institute of Health, London.
In 1892 he came to South Africa as chief engineer to conduct the survey of the proposed Selati Railway in Mpumalanga (1892-1896). Remaining in this country he thereafter conducted the survey of the railway to Pietersburg (now Polokwane; 1896-1898), and became manager of the Pretoria Water Works Company (1898-1903). During the latter period he also served as town engineer of Pretoria (June 1899-1902) and as consulting engineer to the Pretoria municipality (1902-1904). As a consulting engineer his main task was to prepare a plan for an extended water supply for Pretoria, which he completed in December 1903. At some time before 1909 he was registered as a member of the (British) Institution of Civil Engineers (MICE).
On 1 February 1904 Karlson was appointed as hydrographic surveyor in the Department of Irrigation and Water Supply of the Transvaal Colony. In this capacity he recommended the building of Hartebeespoort Dam in 1905 and was later responsible for its construction work until 1921. After the formation of the Union of South Africa in 1910 he was appointed to the same post in the Department of Irrigation of the Union and appears to have held it to about 1921. In 1909 he submitted Evidence to the Power Scheme Commission, on the amount and rational employment of the hydraulic power of the Transvaal (Pretoria, 1909, 71 p), dealing among others with the power needs of the chemical industry and the electrification of railways. A few years later he issued two reports, The campaign against hail and the latest developments of electric means of protection in France (1912) and Report of protection of crops and life against damage by hail and lightning (1913).
Karlson was a supporter of the Kalahari irrigation scheme proposed by the geologist Ernest H.L. Schwarz*. He discussed the scheme in a paper titled "The Kalahari problem", published in the South African Mining and Engineering Journal (1919) in four parts. A reprint of the paper was subsequently published as a pamphlet. He considered the Schwarz scheme to be practicable and discussed means of improving the inland climate, for example by building water reservoirs, large scale irrigation, and afforestation. The next year he wrote a letter to the editor of the Journal of the Royal African Society (1920, Vol. 20, pp. 77-80) in which he claimed to be the original author of the Schwarz scheme, in a memorandum submitted to the Colonial Office in 1913. [For the origin of such schemes, see Gessert, Ferdinand*]
Karlson became a member of the Geological Society of South Africa in 1904 and was still a member in 1915. Both he and his wife, Marie Louise Karlson, were members of the South African Association for the Advancement of Science in 1906, but their membership had lapsed by 1910.