HYDROMODIFICATION

- Final Hydromodification Management Plan (HMP) clean copy (December 2009)
- Final Hydromodification Management Plan (HMP) with markups showing changes from Dec. 11, 2009 draft (January 2010)
 
- San Diego Draft Hydromodification Management Plan (HMP) (updated May 2009)
- Appendix A - San Diego HMP Technical Advisory Committee
- Appendix B - Rainfall Station Selection Criteria
- Appendix C - Summary of HSPF Modeling Reports in Southern California
- Appendix D - Summary of Evaporation and Evapotranspiration Data for the San Diego Region
- Appendix E - Minimum Criteria for Evaluation of Storm Water Controls to Meet IHC
- Appendix F - Flow Threshold Analysis for San Diego HMP
- Appendix G - Lower Flow Threshold Alternatives
 
- Rainfall Data: 

(.wdm rainfall station file, use .csv files for the HEC-HMS program) (DISCLAIMERS: 1. For all projects, the project proponent should contact the governing municipality's project manager to verify that the proper rainfall gauge has been selected.  2. Information contained in the attached data set is preliminary and subject to change in the future.)
  
- San Diego County Rain fall Station Map (November 2008)
- Hydromodification Management Plan Progress Report (July 2008)
- Answers for Common Interim Hydromodification Mangement Criteria Questions (.pdf, May 2008)
- Using Continuous Simulation to Size Storm water Control Facilities (.pdf, May 2008)
- Rain Gauge and Rainfall Data Selection - technical memo (April, 2008)
- Rain Stream Gauge Acquisition Table (Excel)
- Development of Interim Hydrograph Modification Criteria for the San Diego County HMP presentation on February 21, 2008 RWQCB
- Click here for the Interim Hydromodification Criteria document (November 2007).
- A Hydromodification and SUSMP Public Workshop was held on November 19, 2007.
- Presentations from the workshop included: 
- Development of Interim Hydrograph Modification Criteria for the San Diego County HMP
- Interim Hydromodification Criteria document (November 2007)
- Presentation: Development of Interim Hydrograph Modification Criteria for the San Diego County HMP (November 2007)
 

STANDARD URBAN STORMWATER MANAGEMENT PLAN (SUSMP)

- Final Countywide Model SUSMP - Standard Urban Stormwater Mitigation Plan (January 2, 2009)
- Low Impact Development to meet stormwater NPDES treatment and hydrograph modification management requirements presentation February 21, 2008
- Click here for the Revised Model Standard Urban Storm Water Mitigation Plan document - No Redline (February 2008).
- Click here for the Revised Model Standard Urban Storm Water Mitigation Plan document - Redline (February 2008).
- Plans for Standard Urban Stormwater Management Plan Revisions
- Standard Urban Stormwater Management Plan and Interim Hydromodification Management Criteria
- Revised Model Standard Urban Storm Water Mitigation Plan document (February 2008)
- SUSMP Template Update Memo (December 2007)
- Presentation: Plans for Standard Urban Stormwater Management Plan Revisions (November 2007)
- Presentation: Standard Urban Stormwater Management Plan and Interim Hydromodification Management Criteria (November 2007)
 

GEOMORPHIC ASSESSMENT

- Geomorphic Assessment of HMP Flow Control Thresholds presentation (.pdf, May 2008)
- Geomorphic analysis for interim Hydrograph Modification Plan (HMP) (.pdf, May 2008)
 

  
Regional Water Quality Control Board Order R9-2007-0001 Provision D.1.g (6) (Board Order) requires the County of San Diego and its NPDES Co-permittees to identify Interim Hydromodification Criteria (IHC) within 365 days of Order adoption (i.e., by January 24, 2008). The interim criteria will apply until the final Hydrograph Modification Management Plan (HMP) is implemented. The IHC is described in the order as “an interim range of runoff flow rates for which Priority Development Project post-project runoff flow rates and durations shall not exceed pre-project runoff flow rates and durations.” The purpose of the IHC is to prevent development-related changes in stormwater runoff from causing, or further accelerating, stream channel erosion or other adverse impacts to beneficial stream uses. This memorandum provides background on fluvial geomorphology and hydrograph modification management, describes flow control criteria applied in other HMPs, and provides a recommendation for developing the San Diego IHC.