Phytobenthos are good indicators of nutrient enrichment and other pressures, and can be used to assess river water quality. Diatoms are the main plant groups that we use because their silica shells are easy to identify under the microscope. The method is based on the principle that different diatoms have different environmental preferences, so we record the species found, along with their relative abundance.
The latest version of the DARLEQ tool is version DARLEQ 2.0.1, updated 06/08/2014. Click on DARLEQ2Setup.zip below to download the tool.
NB There are some amendments to the EQR boundaries for rivers (and lakes) in the July method statement. These have been revised in the December version.