San Juan Creek Watershed Analysis

PACE was called upon to map the post development condition hydrology of the 175 square mile San Juan Creek watershed.  San Juan Creek watershed located in Orange County, California contains 10 cities, 3 major rivers, and an elevation range from 5,600 feet to sea level.  To complete this project PACE incorporated general plan land use maps from the intersecting jurisdictions, utilized 3 meter digital elevation data from NOAA, and incorporated storm drainage information from the County of Orange.  PACE utilized the latest GIS technology to delineate 73 regional watersheds, 1,270 subwatersheds, over 1,000 miles of flow paths and over 1,000 hydrologic nodes for the entire post-development watershed.  The hydrologic data was incorporated into the ArcHydro data model which standardizes hydrologic datasets and defines each features relationship to the hydrologic network.  The GIS data provided critical hydrologic information that was incorporated into the Orange County Rational Method which generates runoff rates and time of concentration for an Orange County unit hydrograph.


  • ArcGIS ArcInfo
  • Spatial Analyst           
  • ArcHydro
  • AES
  • Vb.Net