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→Pretreatment
===Pretreatment===
===Pretreatment===
*A [[gravel diaphragm]] at the top of the slope is always recommended.
*A [[gravel diaphragm]] at the top of the slope is always recommended.
*When filter strip slopes are greater than 5%, a series of level spreaders (e.g. gravel diaphragms) should be used to help maintain sheet flow.
*When filter strip slopes are greater than 5%, a series of [[level spreaders]] or gravel diaphragms should be used to help maintain sheet flow.
*Filter strips should drain continuously as sheet flow until reaching a [[swales|swale]], [[bioretention]] facility, or other LID practice.
*Filter strips should drain continuously as sheet flow until reaching a [[swales|swale]], [[bioretention]] facility, or other LID practice.
===Berms===
===Berms===
*When designed as a stand alone water quality BMP (i.e., not pretreatment to another BMP) the vegetated filter strip should be designed with a pervious berm at the toe of the slope for shallow ponding of runoff.
*When designed as a stand alone water quality BMP (i.e., not pretreatment to another BMP) the vegetated filter strip should be designed with a pervious berm at the toe of the slope for shallow ponding of runoff.