What studies have documented wetland condition?
Riverine wetlands can stabilize banks, control water temperature, and help to reduce contaminant flow into streams. Therefore any effort to determine the health of California's streams and rivers and answer the question of how many are in good, fair, or poor condition, requires consideration of adjacent riparian wetlands. Because California assesses the condition of its waters biennially, it is conducting a statewide assessment of perennial streams (streams that flow year round).
This Perennial Streams Assessment (PSA) program is a probabilistic monitoring program that assesses selected water quality measures plus the biological and physical habitat conditions in perennial streams. Probability surveys are statistical surveys (like political polls) that allow us to estimate the characteristics of a large population (in this case perennial streams) with relatively small sampling effort. This allows us to produce objective estimates of resource extent and condition with known statistical precision. Probability surveys provide an unbiased picture of the overall distribution as well as context for interpreting site-specific monitoring data. Probability surveys are widely adopted by many state and federal agencies and used for many different types of aquatic resources, including lakes, coastal estuaries, as well as rivers and streams.
The main tool for statewide assessment of perennial streams is bioassessment. Bioassessment (1) is the use of resident aquatic biota, such as benthic macroinvertebates and algae, as direct indicators of the biological integrity of waterbodies. However, the California Rapid Assessment Method (CRAM) is another tool being used by this program to provide a “snapshot” of the ecological condition of perennial streams (similar to a yearly checkup at the physician). The integration of rapid assessment methods, like CRAM, with probabilistic survey designs provides a cost-effective means to make unbiased estimates of wetland condition across large geographic areas.
Much more information about the health of California’s streams and rivers can be found on the Healthy Streams Portal.
(1) Bioassessment is the characterization of environmental conditions through the observation of biological communities of organisms.