Sydney Water Corporation has a Hydrometric Services Group (HSG) which is responsible for measuring clean and dirty water throughout the Sydney Water network. The network spans from Warragamba Dam, where fresh, raw, untreated water enters the delivery network and works through many and varied processes ending up as potable drinking water, used by our customers and eventually discharged via direct or indirect means to the Pacific Ocean. Throughout this large and interconnected network of underground pipes, sewer carriers, filtration plants, pumping stations and water and wastewater treatment/recycling plants, hydrographers are required to accurately measure levels, flows, rainfall and related parameters for various asset management, planning, environmental protection and licence purposes. Within the HSG group, six teams of hydrographers are engaged in the routine monitoring of stages of the network: 1) potable water pressure and flow 2) sewer level and flow 3) wastewater treatment/recycling plant influent, effluent, reuse, bypasses and overflows.

This paper provides an overview of the current hydrometric activities that Sydney Water “city” hydrographers face day to day, with focus on some of the accurate monitoring of underground sewers and treatment/recycling plants. This information will be used to help provide efficient water and wastewater services to a city of over 4 million people while, protecting public health and the environment now and into the future. Why these measurements are undertaken, where, how they are carried out, the associated hazards involved and current and future projects will also be discussed.