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~, <br />During our February 14, 1985 meeting with WECC personnel, Paige Seville and <br />John Ellenberger, John Ellenberger stated that is was the Company's intention <br />to complete a Second Order Class II Survey of its property boundaries and <br />internal property monumentation. I assumed that this same field survey would <br />be utilized to reestablish the triangulation monumentation referenced in Paige <br />Seville's letter of March 7, 1985. No reference is made to the completion of <br />a property survey within that letter. During that same meeting of <br />February 14, 1985, Mr. Ellenberger also discussed the correlation aerial <br />photogrammetric and field surveys completed subsequent to the pre-subsidence <br />survey. In the absence of a proposal by WECC, I recommend that we apply the <br />following success criteria to subsequent surveys. <br />The acceptability of the aerial photogrammetric surveys preformed subsequent <br />to the initiation of subsidence shall be determined by comparison of <br />triangulation and property monumentation locations selected by WECC with <br />Division approval, prior to the initiation of subsidence. A minimum of six <br />selected monuments shall be established for correlation of subsequent aerial <br />photogrammetric surveys. Aerial surveys conducted subsequent to the <br />initiation of subsidence will be accepted as accurate, in the event that <br />photogrammetric and original field survey location results for the selected <br />correlation monuments correlate with an average survey point location <br />deviation of less then 0.2 feet vertically and horizontally, with survey point <br />location deviation of less then 0.4 feet vertically and horizontally for at <br />least 83% of the selected points, and with no survey point location deviation <br />in excess of 0.8 feet vertically or horizontally. <br />We should include the following discussion to govern a situation in which WECC <br />failed to satisfy th above criteria. <br />In the event that any of the aerial photogrammetric subsidence monument <br />surveys fail to meet the above success criteria, WECC shall utilize field <br />survey techniques to discern the reasons for lack of correlation and to <br />correct the discrepancy. If the results of this investigation allows <br />correlation of the aerial photogrammetric survey within the above stated <br />deviation limitations, the aerial survey program shall continue. In the event <br />that the deviation errors cannot be resolved, WECC shall resume traditional <br />field survey monumentation monitoring. <br />/ph <br />cc: Bob Liddle <br />Doc. No. 8514 <br />