Hydrology

Overview
Hydrology Section staff collects and analyzes precipitation and runoff data. They maintain rainfall and stream gauges and equipment. Staff also prepares hydrological analysis of watersheds, data, and engineering charts for use in project development.

Services Provided
The Hydrology Section provides the following services:

Design flow rate and hydrograph services include:

  • Determination of flow rates:
    • 2-, 5-, 10-, 25-, 50- and 100-year flows 
  • Review of flow rates calculated by others
  • Production of hydrographs using our specific unit hydrograph method.
  • Review of proposed watershed modifications such as:
    • Mitigation of increased impervious surface not planned for in current Drainage Area land use maps
    • Proposed revisions and updates to Drainage Area Plans
  • Review of hydrologic impacts of watershed changes to existing hydrologic model
  • Hydrologic data collection, analysis, and reporting
  • Maintenance of rain and stream gauges
  • Collection of rain and stream gauge data from District gauges
  • Collection of published data from EBMUD, National Weather Service, US Army Corps of Engineers, and other agencies gauge data
  • Frequency and correlation analysis of collected data
  • Analysis and reporting of major storm events for understanding of the storms statistical return period
HMS Guidance and Template Model
The FC District has written a draft guidance on how to use the FC District method in HMS. We have also built a template HEC-HMS model that uses FC District methods. This template is available for use by others. Both the guidance and template model can be found through links on the left sidebar of our Documents and Standards page.