# Water Quality Parameters In addition to sediment, nutrients, and pesticides, SWAT+ will calculate the amount of algae, dissolved oxygen and carbonaceous biological oxygen demand (CBOD) entering the main channel with surface runoff. Loadings of these three parameters impact the quality of stream water. This chapter reviews the algorithms governing movement of algae, dissolved oxygen and CBOD from land areas to the stream network. Because the algorithms were based on very limited field data, calculation of these loadings has been made optional. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://swatplus.gitbook.io/io-docs/theoretical-documentation/section-4-erosion/water-quality-parameters.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.