NAC535.250. Requirements for approval concerning earthquakes.

     1. Except as otherwise provided in NAC 535.220, to obtain the approval of the State Engineer pursuant to NRS 535.010, the plans and specifications must, in addition to all other applicable requirements, demonstrate to the satisfaction of the State Engineer that the dam is able to accommodate an earthquake or other extreme motion event without the failure of the dam or any other unintended release of water.

     2. Except as otherwise provided in subsection 3, the applicant must calculate the seismic response to a maximum credible earthquake of a dam and its foundation, including, without limitation:

     (a) Potential liquefaction;

     (b) Loss of material strength;

     (c) Settlement;

     (d) Ground displacement; and

     (e) Wave action due to landslide or seiche.

Ê Any numeric analysis of the seismic response must be calculated for the normal maximum loading condition with steady-state seepage. If a pseudo static stability analysis is performed for an earthen embankment, the calculations must be accompanied by a description of the assumptions used in deriving the seismic coefficient used in the calculations.

     3. Subsection 2 does not apply to a dam classified as low hazard or to a small earth dam classified as significant hazard, if the applicant demonstrates to the satisfaction of the State Engineer that the:

     (a) Static slope stability factor of safety is 1.5 or greater under normal maximum loading with steady-state seepage;

     (b) Peak site acceleration is not greater than 6.5 feet per second squared;

     (c) Materials used in the foundation and embankment are not prone to liquefaction; and

     (d) Slope of the embankment is:

          (1) If the embankment is earthen, not greater than 18.43 degrees from horizontal; or

          (2) If the embankment is free-draining rockfill, not greater than 26.56 degrees from horizontal.

     (Added to NAC by St. Engineer by R124-02, eff. 5-30-2003)