The Western States Water Council (WSWC) has developed the Western Water Conservation Application Tool (WestCAT) that streamlines operations for voluntary, compensated, in-state, and temporary water conservation programs. Measures might include full-season fallowing, alternative irrigation strategies, and crop switching. WestCAT integrates two foundational data sets for water conservation: WestDAAT and OpenET.
- Water rights from the Western States Water Data Access and Analysis Tool (WestDAAT). WestDAAT is user-friendly web-based tool that streamlines access to water right, water supply, water use, and administrative and regulatory overlay data throughout the western United States. It is a part of the Water Data Exchange Program (WaDE), which is a centralized cloud-based data system committed to assisting the eighteen WSWC member states in making their water related date more findable, accessible, interoperable, and reusable (FAIR) through a streamlined and standardized platform.
- Evapotranspiration (ET) data as a proxy for consumptive use estimates using remote sensing technology through OpenET, which provides a user-friendly imagery-based computational estimate of the total amount of water transferred from vegetation and the land surface to the atmosphere through ET. Measuring and monitoring ET on irrigated lands using satellite-based remote sensing has increased over the past couple of decades. OpenET provides a single “ensemble value” from six satellite-data-driven models. Each model currently uses Landsat satellite data to produce ET data at a spatial resolution of 30 meters by 30 meters (0.22 acres per pixel). OpenET data is available through an Application Programming Interface (API) that allows programmatic access to ET data for any field or other prescribed boundary. Any one of the OpenET ensemble models may also be used separately.
Who is WestCAT Made For?
WestCAT supports the following communities: (1) Users, or conservation Applicants, who have agricultural interests such as farmers and ranchers with irrigated acreage. Users could also be municipal or other interests with substantial irrigated lands or turf; (2) Conservation Organizations, who include river basin authorities, boards or commissions, state or federal agencies, municipalities, water districts, canal companies, environmental organizations, or others willing to fund conservation programs; and (3) Technical Reviewers, who may be in-house staff or outside consultants, or state water right administrators evaluating related transfer applications. Access to information might also be provided to irrigation districts, water districts, canal companies or others that are not applicants or program sponsors, but that may be affected by transfers.
Connecting water rights data with consumptive use estimates through WestDAAT and OpenET is expected to help promote federal, state, local, and regional water security and drought resilience activities by enabling and empowering individual Users/Applicants (farmers and ranchers) to consider whether or not to participate in voluntary compensated conservation programs, sponsored by a Conservation Organization. WestCAT is designed to allow a Conservation Organization to evaluate and apply conservation savings for designated purposes, consistent with state water law, while protecting farming and ranching activities long term. It is designed to promote and facilitate different conservation scenarios that fit local needs by providing water rights information in concert with water use data.
How will WestCAT Determine Consumptive Use?
WestCAT will combine both water right data with OpenET data. Water right data from WestDAAT falls under western state water laws, which are based on reasonable beneficial use of a public resource for defined purposes, and once perfected (put to use) the water rights are considered private property rights. Uses may be consumptive and non-consumptive. Waste or unreasonable use of water is prohibited.
OpenET data involves evapotranspiration (ET) which includes evaporation and transpiration from crops that consume water, which often serves as a useful proxy for reasonable beneficial use. Most owners or managers of irrigated lands in the West do not directly measure consumptive use, which is a critical element of water budgeting. Consumptive use includes ET, but also carriage losses from on and off-farm distribution systems, reservoir evaporation, and other irrecoverable water losses, not available for later use, such as deep percolation and outflows to the ocean or terminal lakes.
Total ET from a respective field is a function of both effective precipitation (i.e., rain) and supplementary irrigation (i.e., water right). WestCAT is designed to subtract the effective precipitation from the total ET, resulting in a Net ET estimate, which serves as a proxy for reasonable beneficial/consumptive use. Effective precipitation can be approximately calculated from the ET measurements from nearby non-irrigated land. For compensation for conserved water as measured using this tool, consumptive use includes only Net ET and does not include carriage losses or storage losses. OpenET can provide five-year historical estimates of ET for irrigated fields across the 17 Reclamation States.
Using WestCAT will require registration with the WSWC to ensure Users/Applicants, the Conservation Organization and Technical Reviewers are aware of its capabilities and limitations, particularly the need to understand and comply with state water laws and administrative rules, as well as protect the privacy of all communities.
What are the Steps for the Entire WestCAT Process?
Below is the outline of steps that take place of setting up and using WestCAT:
Step #1: Registration of Prospective Conservation Organization with the WSWC
A Conservation Organization registers with the WSWC for the use of WestCAT. The Conservation Organization determines what rules to evaluate an applicant’s historical consumptive use. For example, the Conservation Organization would decide on the following parameters: (a) the OpenET consumptive use model(s) or ensemble to use; (b) the time period (i.e., number of years and start and end months) used to evaluate historical consumptive use; and (c) the compensation in U.S. dollars per acre or per acre-foot of conserved water offered a user. The Conservation Organization will have view-only access to all submitted applications, but can add comments and change an application’s status (e.g., in-review, accept, or reject).
Step #2: User/Applicants Use of WestCAT Tool to Estimate ET and Savings
After the Conservation Organization has registered with the WSWC, the organization will then perform outreach on all prospective User/Applicants the Conservation Organization has determined can take place in their designated conservation program. Is it not the responsibility of the WSWC or staff to perform outreach, nor will the WSWC assist in determining the best conservation practices to be taken by the Users/Applicants.
Prospective Users/Applicants who have been contacted by a Conservation Organization to take part in the conservation plan can perform the following steps:
- Find their water right through WestDAAT search filters, and select their water right from the map which will direct a user to the respective water right landing page.
- If a selected water right is available for any conservation plan, an optional blue ‘Estimate Consumptive Use’ button will be available which takes Users/Applicants to the Water Conservation Estimation Tool.
- Using the available drawing tools, draw boundaries around one or many fields to estimate their consumptive use through OpenET.
- Click the ‘Estimate Consumptive Use for Drawn Polygon(s)’ button. Based on the results, determine whether or not to explore further.
- Select a supported Conservation Organization from the available drop down which will automatically define the organization’s selected OpenET model, desired start and end dates, and established compensation rate (which are pre-populated based on the organization’s preferences).
- Select the compensation rate either in $ per acre-ft or $ per acre.
- If satisfied with the results, click on the ‘Continue to Application’ button.
- Include contact information and determined conservation plan. If needed, include details on fallowing or crop switching.
- Review drawn boundaries, total ET estimates, and application details.
- If satisfied, click ‘Complete & Submit.’ The User/Applicant gets a confirmation message and can see the status of their application over time. Submitted applications cannot be edited. If any changes are needed the User/Applicant will have to submit a new application.
- Once an application is submitted, WestCAT will send email notifications with links to the submitted application to the User/Applicant (with view-only access), the WSWC staff, the Conservation Organization, and the designated Technical Reviewer.
Below is a short video that showcases how the drawing and estimation tool work.
Step #3: Review of Applications by Technical Reviewer
The Conservation Organization may use an internal Technical Reviewer or may hire a third-party contractor/consultant to perform this function. Using a multi-tier user access in WestDAAT, the Conservation Organization will grant access to the Technical Reviewer for their applications. They can perform the following tasks:
- Review all applications, add comments, and change the application status (e.g., under review, recommend, reject).
- Communicate with the state water rights administration agency and the canal company (if applicable) to verify the Applicant owns the water right or a share in the canal company and may enter into an agreement with the Conservation Organization. There may be some conservation goals that require state consent and cooperation, such as protecting instream flow. If needed, Technical Reviewers can edit applications for accuracy, especially the drawn field boundaries.
- Technical Reviewer will also add a non-irrigated reference area and estimate its consumptive use as a proxy for effective precipitation.
