HM Exceptions & Exemptions
- Projects that do not discharge stormwater runoff into a HM susceptible channel (from the point of discharge all the way to the Bay). Refer to the HM Control Areas for more details.
- A redevelopment project that will not increase impervious area and also will not increase the efficiency of drainage collection and conveyance compared to the pre-project condition. A redevelopment project is defined as a project on a previously developed site that results in the addition or replacement of impervious surface.
Other Exceptions & Exemptions
- Single-family homes not part of a larger development project.
- Transit village developments.
- Brownfield projects or low-to-moderate income affordable housing units within a "Redevelopment Project Area."
Refer to the Alameda Countywide Clean Water Program HM susceptibility map to determine if the project site is within an HM Control Area. The susceptibility map may be referenced at the City of Fremont Environmental Services Division, located at 39550 Liberty Street,  Fremont, CA 94538.
HM Control Standard
- Range of Flows to Control: Post-project discharge rates and durations shall match pre-project discharge rates and durations from 10% of the pre-project 2-year peak flow up to the pre-project 10-year peak flow.
- Allowable low-flow rate: The low flow rate (Qcp) shall be no greater than 10% of the pre-project 2-year peak flow.
- Standard HM modeling: Flow discharge controls using the Bay Area Hydrology Model (BAHM) and site-specific input shall be considered to meet the HM standard.
Additional Information
To download the BAHM or for more information on the HM Standard, visit the Alameda Countywide Clean Water Program website. |
