Manly Hydraulics Laboratory

NSW Public Works

Manly Hydraulics Laboratory

Why MHL Collects Water Quality Data

Water Quality data is collected to provide essential information about the state of NSW estuaries, lakes and lagoons. Baseline data on many parameters are recorded for input into projects undertaken as part of NSW or Local Government programs in areas of estuary, floodplain, coastal and environmental mangement.

What We Monitor

MHL monitors the basic physical water quality parameters of on a continous basis:

temperature,
conductivity / salinity (derived),
pH,
dissolved oxygen concentration,
dissolved oxygen % saturation,
turbidity,
redox, and
water level.

When required MHL staff can take water samples, or install automatic water samplers. These samples can be tested at a laboratory for whatever parametres that are required.

NSW Estuary Management Policy

The NSW Estuary Management Policy was developed to encourage the integrated, balanced, responsible and ecologically sustainable use of the State’s estuaries. The policy is designed to reflect and promote co-operation between the State Government, local government, catchment management committees, landholders and estuary users in the development and implementation of estuary management plans for each estuary.

To assist in the development of estuary management plans, a draft Estuary Management Manual (NSW Government 1992) was published to outline the process of implementation. Essentially, the process consists of eight steps. These steps are:

1. form an estuary management committee
2. assess existing data
3. carry out estuary processes study
4. carry out estuary management study
5. draft estuary management plan
6. review estuary management plan
7. adopt and implement estuary management plan, and
8. monitor and review management process.

MHL is asked to collect water quality data when there is little available data in a water-way, and then this is used in the modeling as part of the estuary processes study. This data collection may be in the form of samples, water quality profiles, or the installation of a continous water quality metre.

Numerical Modeling

Numerical modeling is a series of mathamatical expressions used to describe the behavoiur of a water-way. To do so there are a number of raw data sets required. MHL's water quality data has been used to model a number of NSW's coastal water bodies in the past. The main parametres from the time series instruments of concern are temperature, salinity and water level, as these are required to understand the mixing and flushing of an estaury.

From water samples and samplers, the main use of the data is to model the behaviour of nutrients and susspended sediments during a storm event. This data is combined with the discharge to give a pollutant loading. At some sites both a continuous water quality instrument and a water sampler have been installed, this allows the samples to be collected when there is a change in the physical water quality parameters.

Public education programs through environment centres.

MHL provide near real-time continuous water quality data for environmental centres for public education, through council facilities and environmental centres. One such web site is The Coastal Environment Centre (CEC) is a Pittwater Council Facility which aims to provide environmental information, education and recreation for a broad audience.

Shortlands wetland centre also uses both standalone and telemetred data collected by MHL for community and school group education as well as environmental studies in the Hexham Wetlands, there web site is here:

EPA Licensing
MHL monitors water quality information in industrial and residential areas to assist clients with the EPA licencing requirments.
These clients are local councils, land developers, industrial clients. One such client is BHP Port Kembla Steel works, who can acess their data through the internet.