(1) The worst case scenario shall govern for determining the hazard classification of dams in series where more than one mode of failure is possible among the dams. Classification shall be based on potential for failure under combined and, if applicable, individual dam breach scenarios.

(2) The upstream dam must be classified as a high-hazard dam if:

(a) an upstream dam has the capability to create failure in a downstream high-hazard dam because of its failure flood wave; or

(b) the failure flood wave of the upstream dam will likely cause a loss of life, with or without failure of the downstream dam.

(3) Wastewater ponds that are separated by internal berms are not considered to be dams in series.