Activity
The CEH River Lambourn Observatory

An automatic water quality monitoring station was established on the River Lambourn at Boxford in March 2008. The following river water quality parameters are monitored in-situ at the station: water level, turbidity, temperature, specific electrical conductance, pH, dissolved oxygen and suspended sediment. At the end of April 2010, a new GPRS-enabled datalogger and digital webcam were installed at the site to provide access to real time water quality information. Real time data are used to optimise event sampling, plan field campaigns and identify any instrument malfunctions and maintenance requirements. The webcam will help validate real time data and be used to observe seasonal changes in aquatic and riparian vegetation. Four still images are taken every day at 9am, 12pm, 3pm and 6pm. Data and photographs are transmitted from the remote logger to a computer at CEH's Wallingford site and from there, uploaded to the web. Water quality time series graphs are updated every half an hour, presenting data collected over the previous two weeks. Water level (stage) information is generated from a pressure transducer in the base of the stilling well visible in the foreground of the webcam image. Turbidity data are reported as median values of 100 readings made during the last minute of each fifteen minute interval in Nephelometric Turbidity Units (NTU). Spikes often occur in turbidity records that are produced by biofouling and debris obscuring the sensor lens. These parameters are measured by a YSI 600R in-situ sonde housed in the stilling well which is returned for callibration in the laboratory every two weeks. Specific electrical conductance is temperature corrected to 25°C and reported as microsiemens per centimetre.