Publications

HYDROLOGIC REPORT

This report discusses hydrologic data relative to Los Angeles County. Precipitation, runoff, water levels and water conservation are detailed in annual reports developed electronically since water year 1927-1928. View Report  

2006 HYDROLOGY MANUAL

The 2006 Hydrology manual serves as a guide for hydrologic studies within Los Angeles County. The manual contains current standards and procedures, examples, runoff coefficient charts, and maps of rainfall isohyets and soil types. (PDF) View Document  (123 MB)

HYDROLOGY MAP GIS

This is an interactive GIS viewer application which can be used to search rainfall isohyetals, soil types, and debris producing areas similar to the hydrology maps of Appendix B of the Hydrology Manual. View Site  

SEDIMENTATION MANUAL, SECOND EDITION

This manual establishes the Los Angeles County Department of Public Works' policies, standards and procedures for development of the Santa Clara River, calculating debris production, sediment transport, and design of channels influenced by sedimentation. This edition of the Manual contains updated references to the 2006 Hydrology Manual. (PDF) View Document  (124 MB)

MODIFIED RATIONAL METHOD HYDROLOGY SUPPORT FILES

The files contain design storm data, information associated with land use and soil types, and other support files that can be used with approved software. The data included in these files are to be used in accordance with the methods, standards and procedures detailed in the 2006 Hydrology Manual and the Sedimentation Manual, Second Edition. All files are in zip format. The Tc_Cal_Vol.xls file is no longer accepted and has been replaced by the HydroCalc Calculator.

HydroCalc Calculator (version 1.0.3, released 2/21/2018)
MODRAT Support Files
Rain Depth
Soil Types
Land Use 2005
DPA Zones

WATER SURFACE PRESSURE GRADIENT (WSPG) SOFTWARE

WSPG (Water Surface Pressure Gradient) is a hydraulic software that computes uniform and non-uniform steady flow water surface profiles and pressure gradients in a network of open channels and closed conduits. This tool, originally developed by the Los Angeles County Flood Control District, has been upgraded by Innovyze and is available to download free of charge.

WSPG2018 (released 1/09/2020)

HYDRAULIC DESIGN MANUAL

This manual establishes the Los Angeles County Department of Public Works' Hydraulic Design Procedures. Last update March 2002. (PDF) View Manual  

WATER SURFACE PRESSURE GRADIENT (WSPG) USERS MANUAL

WSPG is a hydraulic analysis system that computes and plots uniform and non-uniform steady flow water surface profiles and pressure gradients in open channels or closed conduits with irregular or regular sections. Last update March 2002. (PDF) View Report  

THE 85th PERCENTILE 24-HR RAINFALL

Spatial Distribution Analysis required selection of gages to represent rainfall throughout the county. (PDF) View Report  

SAN GABRIEL RIVER AND MONTEBELLO FOREBAY WATER CONSERVATION SYSTEM

Maximizing water conservation capabilities to maintain the County's vital supply of groundwater. Learn more about it  

SEAWATER BARRIER ANNUAL OPERATIONS REPORTS

Annual operations reports for West Coast Basin Barrier, Dominquez Gap Barrier, and Alamitos Barrier projects. Learn more about it