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The ET Viewer has built-in tools to help you select an area using irrigation companies or water rights places of use. You can draw a polygon to define your own area-of-interest. Alternatively, you can select your area-of-interest, if it falls within the Eastern Snake Plain Aquifer, by using sets of "irrigated lands" polygons developed by the IDWR. This is explained below.
The ET Viewer uses Esri's ArcGIS Server to allow the user to locate their area-of-interest and compute the evapotranspiration (ET) and consumptive irrigation requirement (CIR) for that area. ET Statistics are computed using Esri's ArcGIS Zonal Statistics as Table geo-processing tool. Your area-of-interest is used (much like a "cookie cutter") to define the portion of the ET dataset on which the statistics are calculated.
The map, to the right, shows the outlines of the ET datasets. The datasets for the eastern part of the state are available for several of the years between 1986 and present, as reflected in the labels. The datasets for the west side of the state are limited to the years 2000 and 2015.
The Find ET page gives you several ways to narrow your search for ET datasets. When you use one of these search-methods, select an item and click the "Search" button, a list of ET datasets which match your search criteria will be shown at the bottom of the page. With the exception of the Browse All ET Data option, the choice you make on this page will make fewer datasets available on the Details page.
For example, if your area-of-interest is entirely within the boundary of the Administrative Basin #37 (Big Wood River) you can select that basin, click the search button and be presented with a list of ET datasets which intersect with that basin. Note: If you select ET datasets by water right or irrigation company, only those ET datasets which completely contain the chosen irrigation entity or water right will be available in the list. You can use the Browse All ET Data option to make all of the ET datasets available for the next page of the application.
The Details page displays the selected ET dataset along with a background and any selected overlays, such as county boundaries, hydrography, etc. Note: If you experience a long wait-time when you initially load the Details page, select a different ET dataset from the drop-down list; wait until it loads, and then select the desired dataset.