Step 5. Stormwater Management Capability
This matrix examines the capability of each STP option to meet stormwater management criteria. It shows whether an STP can meet requirements for:
Water Quality. The matrix tells whether each practice can be used to provide water quality treatment effectively. For more detail, consult the pollutant removal matrix.
Recharge. The matrix indicates whether each practice can provide groundwater recharge, in support of recharge requirements. It may also be possible to meet this requirement using stormwater credits.
Channel Protection. The matrix indicates whether the STP can typically provide channel protection storage. The finding that a particular S TP cannot meet the channel protection requirement does not necessarily imply that the STP should be eliminated from consideration, but is a reminder that more than one practice may be needed at a site (e.g., a bioretention area and a downstream ED pond).
Quantity Control The matrix shows whether an STP can typically meet the overbank flooding criteria for the site. Again, the finding that a particular STP cannot meet the requirement does not necessarily mean that it should be eliminated from consideration, but rather is a reminder that more than one practice may be needed at a site (e.g., a bioretention area and a downstream stormwater detention pond)
This matrix will change depending on the criteria in place within a community. For example, many areas do not require recharge, and this criterion would not appear in their manuals. Second, this section places some practices that do not necessarily meet water quality goals on the "acceptable" list, and uses this matrix to screen them. Alternatively, a community may choose to restrict these practices from the original practice list.
It is important to note that very few practices can be used to achieve recharge. While some of the above practices have groundwater interaction, such as ponds, they cannot reliably provide recharge, as they tend to seal over time. Communities that have a recharge requirement should consider the use of stormwater credits to meet recharge requirements.
Each jurisdiction needs to explicitly dictate which practices can meet existing management goals. Thus, this entire matrix acts as a regulation rather than guidance.