| Popis: |
In this paper, Creager's equation and Group's equation are algebraicaly examined to detemine an equation of an enveloping curve for regional flood peaks from the viewpoint of the curve profile. The applicability of a small drainage area with little observed data on flood peak discharge was examined in comparison to specific flood peak discharge calculated by a rational formula using data of maximum rainfall. In the algebraical consideration, the Creager's equation had an extreme value at a drainage area A=1.0 km2, an the specific flood peak discharge became a maximum. Flood peak discharge calculated by Group's equation had an extreme value at a drainage area A=6,568km2, and it became a maximum. In about 1,178 km2 or less, the value and curve profile of Group's equation using a maximum value of the local coefficient approximated the specific flood peak discharge calculated by the rational formula using the maximum rainfall data from Japan. Except for Hokkaido, the specific flood peak discharge calculated by the rational formula using local data of maximum rainfall considerably approximated the value and curve profile of Group's equation at about 1,178 km2 or less. From the above research results, the Group's equation is applicability better than the Creager's equation, as the drainage area A is 1,178 km2 or less. |
