Water Availability Information

What is Permitting Water Availability Analysis?

A Water Availability Analysis (WAA) is required by the California Water Code as part of processing a water right application. As an applicant, you can expect to prepare a WAA at two steps in the application process.

  • When you file your application. Every water right application submitted to the State Water Board must include "sufficient information to demonstrate a reasonable likelihood that unappropriated water is available for appropriation." (Water Code section 1260(k))
  • During processing of your application. This analysis typically helps meet two requirements in the Water Code:
    • "...In determining the amount of water availability for appropriation, the State Water Board shall take into account, whenever it is in the public interest, the amounts of water needed to remain in the source for protection of beneficial uses..." Instream beneficial uses include, but are not limited to, recreation and the preservation of fish and wildlife habitat. (Water Code section 1243)
    • Before the State Water Board can grant a water right permit, it must find that there is "unappropriated water available to supply the applicant." (Water Code section 1375(d))

Before preparing a WAA, consult with the Division of Water Rights permitting staff contact assigned to your project.

Projects Located in the NCIF Policy Area

WAAs prepared for projects located within the geographic scope of the Policy for Maintaining Instream Flows in Northern California Coastal Streams (North Coast Instream Flow Policy or Policy) should adhere to specific requirements set forth in the Policy.

  • WAAs Completed Prior to Policy Adoption

    If the WAA was completed prior to the adoption of the Policy, see Policy Section 3.3.1.

  • Water Supply Report/Cumulative Diversion Analysis

    The Policy prescribes measures that protect native fish populations, with particular focus on anadromous salmonids and requires that a WAA include:

    (1) a water supply report that quantifies the amount of water remaining instream after senior diverters are accounted for, and

    (2) a cumulative diversion analysis to evaluate the effects of the proposed project, in combination with existing diversions, on instream flows needed for fishery resources protection.

    Applicants may use regional criteria, site-specific criteria, or a combination of the two in the cumulative diversion analysis for assessing whether the proposed diversion affects the instream flows needed for fishery resources.

    Exceptions to diversion criteria may be granted for certain projects involving an application coupled with a reduction of existing diversion under another basis of right.

    • California North Coast Water Availability Tool

      A third party generated methodology for conducting a Water Supply Report and Cumulative Diversion Analysis.

  • Volume Depletion Approach

    The Policy also includes an alternative WAA pathway applicable to certain Class II and III onstream reservoirs. The Volume Depletion Approach webpage has additional information regarding this pathway.

  • Flow Regulated Mainstem Rivers

    The Policy exempts projects located on flow-regulated mainstem rivers from the regionally protective instream flow criteria and the cumulative diversion analysis requirements. However, such projects must still comply with the rest of the Policy, including the policy principles and regionally protective criteria pertaining to onstream dams. The Policy defines flow regulated rivers as a river or stream in which scheduled releases from storage are made to meet minimum instream flow requirements established by State Water Board Order or Decision.

Projects Located in the Delta Watershed

  • Technical Guidance

    The following technical guidance has been developed to provide recommendations for structuring water availability analyses for projects located within the Sacramento-San Joaquin Delta watershed, other than projects for underground storage using the Board’s streamlined approach.

    • Climate Scenario Analysis

      Technical guidance on climate scenario analysis when conducting a WAA within the Delta watershed.

    • Demand Considerations

      Technical guidance on demand-side considerations when conducting a WAA in the Delta watershed.

    • Analytical Framework

      Technical guidance on the analytical framework for conducting a WAA in the Delta watershed.

  • Delta Watershed Water Availability Analysis Tool

    Division of Water Rights staff have developed a methodology for evaluating water availability in the Delta watershed. Runs of this tool are conducted by Division of Water Rights staff.

    • Technical Guidance

      Technical guidance on the Division of Water Rights Delta Watershed Water Availability Analysis Tool (Delta WAA Tool), developed for conducting water availability analysis.

    • Climate Scenario Analysis Staff Report

      Delta WAA Tool Staff Report on the Climate Change Scenario Analysis.

Applicant in need of assistance? If you have a pending application in the Delta watershed and would like to discuss this WAA methodology, please reach out to the staff contact assigned to your application. If you are interested in evaluating the feasibility of a potential project using this WAA methodology, please contact Division staff at dwr-applications@waterboards.ca.gov.

Projects Located in Other Areas of the State

In areas of the State outside of the NCIF Policy area and Delta watershed, there is no set methodology for development of WAA. WAA scope should be developed in consultation with your assigned staff lead. Review of the general approaches to water availability analysis used in other parts of the State as discussed above may help you understand the fundamentals of the WAA process.

Applicant in need of assistance? If you have a pending application and would like to discuss possible WAA methodology, including any recent examples in your watershed, please reach out to the staff contact assigned to your application. If you are interested in understanding permitting WAA approaches that may work for your proposed application, please contact Division staff at dwr-applications@waterboards.ca.gov.

Projects for Recharge by Underground Storage (Streamlined WAA)

The Division of Water Rights (Division) has developed a streamlined permitting process for diversions of water from high flow events to underground storage. The streamlined process will directly assist GSAs and other local agencies working to address SGMA and adverse impacts caused by extractions.

The streamlined permitting process consists of an administrative adjustment in priorities and process. No statutory or regulatory changes were necessary to implement the streamlined permitting process, except for lowering of the associated fee schedule. Streamlining is primarily achieved through identifying eligibility criteria and a simplified water availability analysis (WAA) targeting diversion of high flow events during winter. These criteria and analyses will ensure applications are unlikely to injure other legal users, adversely affect fishery resources, or other public trust resources.

Option 1: Relies on a predetermined threshold to show the presence/ absence of high flow conditions and protects critical ecosystem functions associated with high flows by applying a conservative cap on the amount of water that can be diverted rather than analyses that often require highly site-specific information and a detailed technical investigation. The predetermined threshold explicitly assumes that flows above the 90th percentile daily flow, between December 1 and March 31, are protective of aquatic ecosystem functionality if the total amount of water diverted is capped at 20 percent of the daily flow. A telemetered gage located near the POD will be the means for demonstrating high flows are present and how much may be diverted without exceeding the 20 percent limit. Staff have developed a WAA for Streamlined Recharge Permitting guidance document describing how to implement this methodology and what technical resources are available.

Option 2: Relies on the presence or imminent threat of flood conditions to demonstrate water availability. An applicant may demonstrate water availability be proposing to divert when flows exceed thresholds that trigger flood control actions necessary to avoid threats to human health and safety, according to established written flood management protocols adopted by a flood control agency.

  • Guidance Document

    This technical guidance is provided to assist in the simplified water availability analysis for applications using the streamlined permitting process for diversions of water from high flow events to underground storage.

Applicant in need of assistance? Early outreach and consultation with Division staff is critical for WAA development using the streamlined permitting process for a recharge (underground storage project). Please note the pathway is not available to other methods of diversion. Prospective applicants are encouraged to discuss their projects with Division staff in advance and provide a draft copy of the WAA for review and comment. If you are interested in understanding if this approach may work for your proposed application, please contact Division staff at dwr-applications@waterboards.ca.gov.

Additional Water Availability Analysis Resources

Still have questions?

Contact the Division of Water Rights permitting section at dwr-applications@waterboards.ca.gov.