LAKE DIAGNOSTIC SYSTEM

Introduction

The Lake Diagnostic System (LDS) has been developed over a period of twenty years at the Centre for Water Research (CWR) based at The University of Western Australia.  Originally, used as a tool for collecting data for fundamental research of lakes it has now become a tool for long-term reservoir water quality monitoring and management for fresh and estuarine water managers around the world.

The LDS provides fine scale resolution measurements for water column temperature, conductivity, dissolved oxygen, turbidity, chlorophyll-a and above water meteorology. Data is transmitted to a shore station, and from there is displayed online in real-time. A key feature of the LDS is the fast response and high-resolution thermistor chain, allowing complete measurement of the water column stratification in < 5 seconds.

Lake Diagnostic Systems are suitable for installation in enclosed water bodies as well as coastal embayments, estuarine and lagoon ecosystems. In both Australia and internationally, Lake Diagnostic Systems are installed in lakes, estuarine systems and portable water supply reservoirs and play an important role in the management of public water resources.

In 2009, The Centre for Water Research and Routers Australia, now trading as Global Water Monitoring entered a joint venture to design and manufacture the entire LDS components in Australia. This exciting partnership is set to dramatically reduce lag time for customer orders, and has revolutionised many aspects of the Lake Diagnostic System Design.

The LDS has a TIG welded 316 Stainless Steel frame supported by an arrangement of floats. This framework (station) has a large stainless steel perforated disk (diffuser) attached to the central supporting column that dampens the station in windy conditions and waves.

This device reduces bobbing, pitch and roll dramatically, enabling attached sensors to maintain a known depth in water. The floats maintain a central buoyancy that keeps the station extremely stable on all plains.

Attached to the station is a series of mounting points above the water line where meterological sensors can be fitted. Such as Wind Direction/Air Speed, Relative Humidity/Air Temp, Short Radiation/Net Radiation. Aerials are also mounted on this array as well.

Solar panels are attached (2 x 10 watt as standard) on the mast well above water level.

Item Spec / Material
Frame Laser cut/CNC Machined / TIG welded / 316 stainless steel
Logger box / Casing ABS plastic from USA CNC Machined and pressure tested. Seacon deep sea connectors.
Thermistor Inconel 625 - extremely inert material surrounding a German made high end thermistor, suitable for measuring fine scale temperature variability. Resolution of 0.0001 deg C provided. Housed in precision molded polyurethane casing. This molding encases the 20 bit processor circuit board and 5-7 year lithium battery transmitting temp data to the T-Chain
Data Logger 20 bit ADC with acquisition rate of 5 seconds.  Backup memory.  Real time data acquisition can be sent via GSM phone network, satellite, radio, land line or a combination of the above
Wind Sensor RM Young Wind Monitor direction and speed 0 to 100 m/s (224 mph)
Temperature/Humidity

Visala HMP155- 100% RH.  Temp Range (-80) C to 60C

Solar Global Radiation EQ08/E Solar Pyranometer
Solar Net Radiation CN1-R Net Pyrradiometer Matched Shortwave and Longwave sensitivity
Pressure Sensor measuring ranges: 0~0.2, ..., 0~200 mH2O
Dissolved Oxygen Sensor OxyGuard Cat No D123M Model 525 Oxygen probe for use with data loggers, modified to include special vent for 60m deep water measurements and including antifouling cap.
Chl-A Sensor WETLABS ECO-FL-S chlorophyll -A  Flurorimeter with motorised copper shutter/wiper antifoul system, analog output 0-5 volt.
Conductivity Sensor Conductivity sensors EC 250.  Range and non-normalized or normalized to be determined by GWM for each specific job output 0-2.5 volt.
Turbidity Sensor

1 NEP9504GP ANALITE Turbidity Probe 90⁰, 0-400NTU, V2 version with 0-2.5V output, 9.6-28Vdc power. Includes motorised wiper assembly.

GWM manufactures high resolution temperature sensors (designed by CWR) that is attached to a T-Chain (Temperature Chain). These unique temperature sensors allow accurate readings to 0.0004 degrees.

A high end thermistor is housed in a precision made Inconel 625 tube, enabling fast and accurate readings to obtain accurate modelling of the Thermoclines in real-time.

This sensor is housed in a unique polyurethane molding. The sensor can then be mounted on a specially designed chain of receivers (Nodes) that are connected to a data logger. The chain is able to communicate to these sensors (eg Temp) without wiring! This induction method of transferring data allows easy replacement of sensors and less than a minute to slip and lock a sensor onto the chain.

You don't need to have the T-chain sent back for calibration as the sensors can be replaced, enabling an easy swap over of sensors. THIS ENABLES CONSTANT ACCURACY AND UNINTERUPTED MONITORING.

The 20bit multi-channel Digital data logger is encased in a Precision CNC machined case, made of ABS. This canistor can be used in 90% of the water locations on the globe. The heavy duty case allows the data logger to be sealed under water maintaining a stable temperature. This is extremely desirable in all weather conditions.

Global Water Monitoring also produces an out of water casing that can be mounted in all terrain or on buoys. This casing has advantages in that it is cost saving and can be mounted quickly to suit your data-logging/transmission needs.

The GSM Modem allows data to be sent over the cell phone network (Scans all country's frequency bands). Data can be sent via cell phone network to land server/computer. All sensor data from logger can be sent every minute or at any time interval that the customer requires.

Depending on location, data can be sent via satellite or radio transmission.