SPDSS_Task91_MapIrrigationDistributionSystems_20070109

• Title: SPDSS Task 91 - Map Wells, Irrigations Systems and Irrigation Service Areas
• Description: This memorandum summarizes the procedures for the 2001 irrigated parcel mapping prepared under Task 91 – Map Wells, Irrigation Systems, and Irrigation Service Areas.
• Decision Support - Doc Type: Task Memorandum
• Date: 1/9/2007
• DSS Category: GIS
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153960
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Riverside Technology inc.

MEMO -TASK 91
The boundaries were evaluated to ensure that they did not overlap or have unnecessary gaps. Some
legitimate overlaps were present; for example, when two ditches crossed each other and it appeared that
the land could be irrigated by both ditches.
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Figure 3. Example of Irrigation Service Areas with Diversions, Ditches, and Elevation
The last step required attributing the preliminary service area boundaries with the primary diversion
structure identification number (WDID) and the name of the ditch company supplying irrigation water.
The preliminary service areas were also assigned a status attribute. The status attribute was later used to
track the progress of meetings with the different ditch companies.
2.2.2 Assign Diversion IDs to Irrigated Parcels Using Service Areas
After preliminary service area boundaries were created, the diversion structure IDs were assigned to the
preliminary irrigated parcels. Each parcel was attributed with the WDID of its corresponding service
area. Parcels that overlapped more than one service area boundary were attributed with the WDID of the
service area in which the center of the parcel was located. These parcels would be clarified during
meetings with water users. Irrigated parcels outside any service area boundary were defined as
`groundwater only' irrigation. If there were no wells near the `groundwater only' parcels, they were
marked as questionable areas and resolved during water user meetings. Figure 4 shows the key diversion
structures, decreed irrigation wells, irrigation ditches, 2001 irrigated parcels color coded by the irrigation
service area boundaries and labeled with `ground water' only labels (GW), and the Image Base Map.
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