Modeling tool under development to predict biological consequences of ionic stress

SCCWRP and its partners have begun developing a modeling tool to help Santa Ana River watershed managers understand the relationship between ion levels in the watershed and how aquatic life will be affected as these levels rise.

The project, which kicked off last fall, is designed to help watershed managers understand how to apply a set of existing Santa Ana basin objectives that cap the concentrations of several major ions, including chlorine and sodium, and provide prescriptive requirements for related indicators of ionic stress, including water hardness.

None of the indicators have been correlated with biological effects in aquatic life, limiting managers’ ability to effectively use these indicators to manage ionic stress across the Santa Ana region.

The project involves developing models that predict when ionic stress can be expected to adversely harm in-stream biological communities. The models will predict the biological consequences of ionic stress at nearly every stream in the Santa Ana, eliminating the need to calibrate numerous site-specific biogeochemical models.