Plynlimon Hydrometric Review 2008

This Review describes the streamflow and weather data collected in the Plynlimon catchments during the calendar year 2008. Hydrochemistry data are dealt with separately (although this may change in future). This forms one of a regular series of semi-formal reports with 3-fold aims: i) to foster prompt data processing and quality control, ii) to record events and changes in the catchments as a store of background information for data users - contemporary details all too often ‘buried’ in field notebooks, iii) to provide a brief review of the current catchment hydrology and any notable hydrological events, and to extend the data record from the currently most recent published account on the hydrology of Plynlimon (Marc and Robinson, 2007). The core hydrometric network comprises streamflow gauges, providing 15-minute discharges, and automatic weather stations (AWS) recording hourly data. This Review is primarily concerned with assessing these data using visual, statistical and analytical techniques, and providing a record of the data quality control procedures and catchment metadata. A known error in one of the AWS sensors (the calibration of air temperature at Eisteddfa Gurig) has been deliberately used to demonstrate the effectiveness of these data checks.