> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_b.md). # vol\_dp\_b The parameters [vol\_area\_co](/io-docs/introduction-1/wetlands/hydrology.wet/vol_area_co.md), [vol\_dp\_a](/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_a.md) and vol\_dp\_b are coefficients that control how strongly the wetland surface area changes as storage volume changes relative to principal storage. They are used for wetland initialization and to update wetland area for each simulation time step. [vol\_dp\_a](/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_a.md) and vol\_dp\_b are used to infer wetland depth from current storage volume. They are not used independently in a physically transparent way but rather interact through the quadratic. If [vol\_dp\_a](/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_a.md) is smaller than vol\_dp\_b, the wetland surface area shrinks more strongly when water volume declines. If [vol\_dp\_a](/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_a.md) is larger than vol\_dp\_b, the wetland keeps a larger surface area even at lower storage. [vol\_area\_co](/io-docs/introduction-1/wetlands/hydrology.wet/vol_area_co.md) is used to convert the wetland depth to wetland area. The final area is clipped between 0.01 and 1.0, so the effect of extreme values of [vol\_area\_co](/io-docs/introduction-1/wetlands/hydrology.wet/vol_area_co.md), [vol\_dp\_a](/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_a.md), and vol\_dp\_b may get hidden by those limits. The wetland area affects seepage, groundwater exchange, depth/release calculations, and constituent settling. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://swatplus.gitbook.io/io-docs/introduction-1/wetlands/hydrology.wet/vol_dp_b.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.