Unchecked data has not been reviewed, it has been recorded at the gauging station and transferred straight to the website. Checked data has been through a plausibility check by the hydrometry and telemetry team at the Environment Agency and is deemed to be the best available. During the check the expert will label the data with one of our quality flags outlined below. Please note that the checked data can still be revised. We recommended that you download the full time period you are interested in each time before you undertake any analysis, so that any revised data is included.