Utility Location in Saxonwold, Johannesburg

Customer: Johannesburg Water (Municipality) - Mr. Tshepo Ramatlo

Site: Saxonwold, Houghton, Johannesburg. Saxonwold is a suburb of Johannesburg, South Africa. The suburb has its origins as part of the Braamfontein farm which was owned by Hermann Eckstein. He had bought the farm to explore it for minerals and when he failed to ﬁnd any, the land was converted as a timber plantation in 1891 called Sachsenwald. The land's name was anglicized at the beginning of World War One and was called Saxonwold. In 1903, Wernher Beit & Co and Max Michaelis gave 200 acres of freehold ground in the Sachsenwald plantation to the Johannesburg Town Council for the use by the people of Johannesburg by the creation of the Herman Eckstein Park. This park would become Zoo Lake, the Johannesburg Zoo and the South African National Museum of Military History. The remaining land in the plantation was developed into a township called Saxonwold in 1925 by the Transvaal Consolidated Land & Exploration Co Ltd.

Systems/Equipment: LMX 200 (Ground Penetrating Radar) with GPS and the Utilitrac R130.

Ground Penetrating Radar (GPR) has been used worldwide over the past couple years for shallow subsurface investigation. It is a high resolution electromagnetic (EM) method that uses the diﬀerences in dielectric properties of subsurface objects to detect and locate features. GPR's transmitter antenna sends high rate EM waves (10-2000 MHz) toward the ground and the backscattered and reﬂected signals are detected by the receiver antenna.

Date: November 2019 – 2 full weeks spent on site.

Situation: Johannesburg Water is in the process of upgrading the water mains in and around the Saxonwold area in Johannesburg. Orsco (Pty) Ltd was appointed to map and locate all shallow services in and around the proposed area and an estimated total of 15 000 meters of road and pavement were surveyed on and near the planned trenching line.

Solution: Using a combination of ground-penetrating radar (GPR,) GPS and electromagnetic scanning, the existing underground services were scanned and mapped by Orsco. All the identified utilities and services were marked on the ground to assist with immediate trenching. These services included gas, electrical, Telkom and fibre optic cables as well as potable water, stormwater and sewerage lines. All findings were mapped (full GIS Auto Cad map) and a full report was supplied to the client.