Re: Field Work for Mixed-Source and Soft-Conversions Assessments

MEMORANDUM

To: Rick Raymondi Brian Patton Fr: Bryce Contor Date: 27 September 2007, Revised 2 October 2007

Re: Field work for mixed-source and soft-conversions assessments ______The "refinement of methods" tasks for the ESPAM 2.0 data gathering project and the "soft conversions" task of the Interim Measures project require assessment of the water right, water supply and infrastructure status of a statistical sample of parcels that are currently identified as "mixed source." This memo reports on the assessment of the nine samples closest to Idaho Falls and seeks input on the best use of resources for analysis of other parcels.

Four activities are available to assess each parcel. On three of the parcels only the first activity was applied. All of the activities were applied to the other six parcels. Table 1 shows how many of the activities were required to achieve reasonable certainty of the water source on the sample parcels. The analysis started with the GIS analysis of aerial images and water- right polygons, and proceeded down the list.

Table 1 Level of Activity Required to Achieve Reasonable Certainty of Water Source

Activity Number of Sites Comments Requiring this Activity GIS review 3 These results were unambiguous; no further activities were applied to these three samples. Water-right and 5 adjudication scanned files WMIS, Water District 1 Most of these paper files were ambiguous about and GWD paper files surface-water infrastructure; they focused on the well source only. Five of the six paper-file examinations added no certainty to the analysis. Field Inspection 0 Half of the field inspections would have been ambiguous without the other activities.

While field inspection added very little value in the determination of water source, it did aid the assessment of infrastructure required to deliver surface water to the parcel. Table 2 lists the sites visited and the infrastructure assessments before and after the field inspection. Sites marked "N/A" are shown by water-rights data to be single source. Table 2 Field Inspection and Assessment of Infrastructure Requirements

Site Office Determination Field Determination 20 pump, 525 feet powerline, 525 feet pump, 525 feet mainline (slope is wrong mainline or ditch for ditch)1 28 N/A field inspection would have been impossible; no access via public roads 92 pump, 1/4 mile mainline or ditch, pump, either 1/2 mile ditch or 1/4 mile zero to 1/4 mile powerline mainline1 118 pump, 1/4 mile mainline or ditch, pump, 1/4 mile ditch1 zero to 1/4 mile powerline 124 N/A not inspected 127 infrastructure already in place field inspection was ambiguous; no access to pump site via public roads 140 pump, 1/4 mile mainline or ditch pump, 1/4 mile mainline, 1/4 mile powerline 142 pump, 1/8 to 1/4 mile mainline pump, 1/8 mile mainline 154 N/A not formally inspected but drive-by indicates field inspection would have been possible

In reviewing these data and the resources available, and after consultation with both of you, it appears that the best approach is to do an office review of 300 samples and field inspection of a subset of 50 samples. The office review will proceed in the order of Table 1, incorporating as few or as many steps as needed to obtain an unambiguous indication of water source with reasonable certainty.

The field inspections will be selected from sites that office review suggests have both ground- water and surface-water rights, but only ground-water infrastructure. The primary purpose of the field inspection will be to confirm and refine our estimates of the infrastructure requirements to restore the capability of surface-water deliveries.

This memo only addresses the field work/site review portion of both the IWRB work and the IDWR work.

Additional work to be performed for IWRB will be to evaluate historical diversion volumes and seasonal diversion volumes to assess system capacity on both a mid-season and shoulder- season basis. We will also contact canal operators for assistance in assessing delivery capacity.

Additional work to be performed for IDWR will be to assess Water Measurement District, Ground Water District and Water District records of ground water diversions, to aid in calculating the mix of supply on mixed-source lands. There are five years more data available now than when these sources were first assessed during model calibration.

1 The ditch determination could possibly have been made in the office with topographic maps, but this was not part of this first round of office review.