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Table 1 <br />Irrigated Acreage by Designation <br /> <br />Acrea e Desi nation Acres Identified as <br />Irri ated Percent of <br />Total Acrea e <br />Key Surface Water Structures 746,700 73.5 <br />Non-Key Surface Water Structures 102,800 10.0 <br />Ground Water Only Structures 166,700 16.5 <br />Basin Total 1,016,200 100 <br />Approach <br />The following approach was used to review the 2001 Irrigated Lands Assessment <br />(version as of 3/15/06) in Division 1 and Water District 47. Note that because of the <br />detailed diversion record review of key structures in Task 3 and because service areas <br />have been designated for key structures, slightly different approaches have been taken to <br />review key versus non-key structure acreage. <br />General approach for acreage review of key structures: <br />1. The following ArcGIS shape files were used: <br />^ Divl_irrig_2001_20060315.shp (Irrigated Lands) <br />^ Divl_diversions_20040930.shp (Headgate Locations) <br />^ Divl_rivers.shp (Rivers and Canals) <br />^ Dist12364_servicearea_20060315.shp (Service Areas) <br />2. Visual inspection of each key structure headgate location in relation to its <br />corresponding irrigated acreage was performed. The Service Area and Rivers <br />shapefiles were also utilized in the visual inspection. In addition, USGS <br />topographic maps were used. The visual inspection checked for <br />a. Headgate location with respect to parcels <br />b. Parcels location within assigned service areas <br />c. Parcel location with respect to canals (if available) and topography <br />General approach for acreage review of non-key structures: <br />1. WDID's with assigned acreage were compared to WDID's in HydroBase to <br />identify invalid WDID's, or structures without water rights. Note that this review <br />has previously been performed for key structures <br />2. A comparison was performed to identify WDID's with acreage assigned, but no <br />diversion records in HydoBase. This review for key structures was performed in <br />Task 3. <br />The 1956, 1976, and 1987 historical irrigated acreage coverages were also reviewed in a <br />more generally fashion. The general approach for the review of historical coverages was <br />as follows: <br />1. Check that parcels in the coverages are attributed with a WDID or well permit, <br />crop type, and acreage. Note that parcels in the 1956 coverage are assigned crop <br />types based on the recommendation in the SPDSS Task 71 memorandum (LRE, <br />October 31, 2006) <br />2of12 <br />