Biomonitoring and habitat assessments are two tools that stream ecologists use to assess the water quality of a stream. Biological monitoring involves the use of organisms to assess the environmental condition. Biological observation is more representative as it reveals cumulative effects as opposed to chemical observation, which is representative only at the actual time of sampling. Biomonitoring a water body ecosystem uses the same theoretical approach. Aquatic macroinvertebrates are subject to pollutants in the water body. Biomonitoring surveys are conducted before and after an anticipated impact to determine the effect of the activity on the water body habitat. Biological sampling allows for rapid and general water quality classification. In a biological sampling program, the most common sampling methods are the transect and the grid. Alkalinity is important in water treatment plant operations. For example, testing for alkalinity in potable water treatment is most important for its relation to coagulant addition.