The variables monitored routinely at each site to assess water quality are chlorophyll a, light penetration (as attenuation coefficient and Secchi depth), pH, oxygen concentration, salinity, temperature, nitrogen (as nitrate plus nitrite, ammonia and total) and phosphorus (as phosphate and total).
Macroalgae are assessed visually as percentage cover, and quantitatively as dry weight biomass enclosed in 64 cm2 cores pushed into the sediment.
A separate programme, not detailed here, addresses sediment properties (nutrient concentrations and nutrient release rates). Other monitoring programmes are now carried out by Government agencies concerning river discharge and nutrient concentrations in river water.