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<br />~ <br /> <br />~ <br /> <br />, <br /> <br />It will instruct owners about the care, inspection and <br />maintenance of dams~ oath to prolong the dam's useful <br />life and to provide for its safe operation, <br /> <br />B. You asked about whether additional criteria should be <br />.used in designating high hazard dams tnat requ~re more <br />frequent examinations. <br /> <br />r <br /> <br />During the early 1970's, Alan Pearson developed a <br />hazard rating/frequency of inspection procedure based <br />upon a weighted analysis using dam height, reservoir <br />capacity, estimated evacuation and potential downstream <br />damage. It included two parts. The first established <br />the hazard rating and the second, using a grid of <br />hazard potential versus number of inspections9 was a <br />guide on how many times a dam should be inspected. The <br />guide indicated high hazard dams would be inspected <br />more than once a year and low hazard dams would be <br />inspected about once in five years. It was not <br />implemented at that time because of a belief dams must <br />be inspected once a year. As shown below, this is not <br />the law and the proposal should aga~n be reviewed. <br /> <br />The first part of the procedure was used for several <br />years and was the basis of the State's initial hazard <br />ratings for the national inventory of dams. It was <br />eventually replaced with the rating work for the NDSP. <br /> <br />There is merit in creating guidelines similar to those <br />descihed above. They would enable more quantitative <br />criteria for ~dentifying "critical" dams that require <br />ongoing safety evaluations. <br /> <br />It is more difficult to quantify a method for <br />inspecting "deteriorated conditions.'1 This is a <br />judgment whiCh must be made by field engineers and <br />reflected in their recommendations. <br /> <br />C. Present inspection schedules call for all high hazard <br />dams to be inspected within the year. Those structures <br />known to be of particular concern will be, or have been <br />already, inspected first. This SChedule is deemed <br />adequate to meet the objectives of the state dam <br />inspection program. If it is determined that all high <br />hazard dams should be inspected sooner than the one <br />year time frame, additional funding from outside the <br />present State Engineer's budget will be necessary. <br />Attachment E shows the number of high and moderate <br />hazard dams inspected since 1978. <br /> <br />If necessary, consulting engineers should be retained <br />to make inspections during this season. All dams under <br />restrictions should be inspected. Any dam under <br /> <br />4 <br />