The Riparian Zone Estimator Tool (RipZET) is a decision support tool developed by the San Francisco Estuary Institute and Aquatic Science Center for the California Riparian Habitat Joint Venture and the California Water Resources Control Board to assist in the visualization and characterization of riparian areas in the watershed context.

RipZET works within a Geographic Information System (GIS) to estimate the likely extent of riparian areas based on the concept of “functional riparian width.” According to this concept, different riparian functions can extend different distances from their adjacent surface waters, depending on topographic slope, vegetation, land use, and position along a drainage network.  RipZET translates this concept into estimates of riparian width for selected riparian functions, and the tool is modular so that new functions can be added as needed. RipZET provides reach-scale estimates of the riparian width associated with the relevant riparian functions (e.g., large woody debris supply in wetlands and in headwater channels or floodwater storage in low-gradient alluvial channels). RipZET’s ability to visualize and quantify riparian widths and lengths for selected riparian functions makes it a powerful tool for assisting in the development of effective riparian management and restoration approaches throughout the state.

RipZET uses three discrete modules to estimate functional riparian width:

  1. Hillslope – Estimates functional riparian width in steep headwater channels based on adjacent hillslope gradient. Targeted functions include large woody debris input and coarse sediment input
  2. Vegetation – Estimates functional riparian width in all channel types based on adjacent hillslope gradient and mature vegetation height. Targeted functions include bank stability, channel shading, and run-off filtration
  3. Hydrologic Connectivity – Estimates functional riparian width in low-gradient, alluvial channels based on flooding inundation extent. Targeted functions include floodwater storage and groundwater recharge.

The modular design of RipZET makes it possible to add new modules for different riparian functions. New modules to estimate the degree of channel incision and the impact of shading on water temperature are being planned.

Download RipZET Tool and User's Manual

This video provides an overview of the RipZET tool and scientific basis for each module.


RipZET Tool and User's Manual

You are about to download an 30 MB zip- file that contains a readme text file to get your oriented, RipZET(an ArcGIS based tool), and the RipZET User’s Manual.

System requirements:

  • 8GB RAM recommended
  • ArcGIS Desktop 10.x
    • Extensions: Spatial Analyst, 3D Analyst (HyCon module only)
    • ArcPy 2.7
    • ArcGIS 64-bit background geoprocessing support recommended
  • Microsoft Excel (HyCon module only)

To use the RipZET modules, the following inputs are required for the user-defined area of interest:

  • Stream line or wetland polygon features (shapefile or ESRI feature class)
  • Vegetation polygon features (shapefile or ESRI feature class)
  • Degree-slope raster
  • High-resolution LiDAR (0.5m recommended)
  • Site point features (shapefile or ESRI feature class)

RipZET outputs include an ArcGIS map document and an ESRI file geodatabase containing the following:

  • Estimated functional hillslope riparian polygons
  • Estimated functional vegetation riparian polygons
  • Estimated 2-, 10-, and 50-year flood inundation extent points

More Info

The loss of riparian areas throughout California has greatly impacted water quality and habitat conditions, which has resulted in a number of challenges for resource managers and the public in terms of water management and land use planning. Riparian areas, or floodplain areas adjacent to streams and wetlands, provide a multitude of functions or ecologic services for their adjacent aquatic habitats including shading, bank stabilization, organic and inorganic input, filtration, ground water recharge, and downstream flood reduction. In the face of ongoing development and climate change, there is a great need for land use planners to have tools available that can help them delineate and map the desired extent of riparian functional areas in developed watersheds targeted for restoration or relatively undisturbed watersheds targeted for development. RipZET was therefore developed with funding from the California Water Resources Control Board to provide functional riparian width estimates and help support riparian management and restoration decisions.

RipZET was developed using the state-of-the-science regarding riparian functioning and has been tested in the San Francisco Bay Area, as well as in the Tahoe Basin and Central Coast. The tool was developed over a 4-year period with close oversight by regional scientists and management experts. The tool is intended to be used widely and able to be run by scientists and planners with a moderate degree of proficiency using GIS and spreadsheet software.


RipZET would not have been possible without the strong leadership of the project Technical Advisory Committee (TAC). The RipZET TAC consisted of habitat restoration scientists, resource planners and managers from federal, state and/or local agencies. TAC members participated in a series of meetings to advise and review tool design ideas, and monitor progress during tool development. Some “Core TAC members” were also involved in extensive scientific discussions with the project team outside the TAC meetings and helped to vet tool design ideas and functional recommendations that were presented to the larger TAC for review. The project team would like to thank all the TAC members for their invaluable contribution over the past 4 years.

In addition, we would also like to thank Roger Leventhal (Marin County Department of Public Works) and Laurel Collins (Watershed Sciences, Berkeley, CA) for their contribution of the “Regional Curves of Hydraulic Geometry for Wadeable Streams in Marin and Sonoma Counties, San Francisco Bay Area Data Summary Report” (May 10, 2013), which provided necessary hydraulic information for building the tool.

List of RipZET Project TAC Members.

* Indicates Core TAC Members



Department or Program

Ben Livsey

Bay Area Water Quality Control Board

Stream and Wetland System Protection

Chad Roberts*

Roberts Environmental & Conservation Planning, LLC

Environmental Science

Cliff Harvey

State Water Resources Control Board

401 Certification

Elaine Blok*

US Fish and Wildlife Service

National Wetland Inventory

Eric Berntsen*

State Water Resources Control Board

Storm Water Division

Eric Stein*

Southern California Coastal Water Research Project

Watershed Science

Gordon Leppig*

CA Department of Fish and Game

Habitat Conservation Program

Jason Schwenkler

CSU Chico

Director of the Geographic Information Center

Jeanne Chambers

US Forest Service

Grassland, Shrubland and Desert Ecosystems (GSD) Program

Kris Vyverberg*

CA Department of Fish and Game

Fisheries Management

Roger Levanthal*

Marin County

Public Works Department

Shawna Dark

CSU Northridge

Geography Chair

Stefan Lorenzato*

Department of Water Resources – Riparian Habitat Joint Venture


Steve Greco*

UC Davis

Landscape Architecture

Terry Huffman

Huffman-Broadway Group, Inc

Wetland Science

Todd Keeler-Wolf

CA Department of Fish and Game

Biogeographic Data Branch

Programs and Focus Areas: 
Environmental Informatics Program
Geographic Information Systems
Software Engineering
Resilient Landscapes Program
Wetland Monitoring & Assessment
Watershed Science & Management
Location Information
Package icon RipZET for py3.x v1.08.33 MB