The main purpose of a detention basin is to temporarily store runoff and to reduce peak discharge in the downstream conveyance system so that its capacity is not exceeded. The determination of required detention storage is based on volume calculations derived from the inflow hydrograph, along with the maximum outlet flow. In this work, utilizing a design storm approach, a yetograph with a variable intensity is proposed to maximize the volume of detention basins. The reliability of the yetograph in assessing a design volume which does not excessively overestimate the real ones is shown. The hyetograph is obtained deriving the depth-duration-frequency (DDF) curve, with respect to the duration, and drawing the resulting function so that the intensity increases with the duration. Since the starting hyetograph has an infinite duration, first a specific duration is chosen and then a constant intensity, corresponding to the selected duration, is assumed for the whole preceding period. The reliability assessment of the proposed hyetograph is shown by schematizing the rainfall-runoff process within the catchment by means of Nash’s model while the detention basin behavior is simulated by a linear reservoir model. The proposed hyetograph can be even coupled with more sophisticated models of detention basins.

A design hyetograph for detention basins

DEL GIUDICE, GIUSEPPE;RASULO, GIACOMO
2003

Abstract

The main purpose of a detention basin is to temporarily store runoff and to reduce peak discharge in the downstream conveyance system so that its capacity is not exceeded. The determination of required detention storage is based on volume calculations derived from the inflow hydrograph, along with the maximum outlet flow. In this work, utilizing a design storm approach, a yetograph with a variable intensity is proposed to maximize the volume of detention basins. The reliability of the yetograph in assessing a design volume which does not excessively overestimate the real ones is shown. The hyetograph is obtained deriving the depth-duration-frequency (DDF) curve, with respect to the duration, and drawing the resulting function so that the intensity increases with the duration. Since the starting hyetograph has an infinite duration, first a specific duration is chosen and then a constant intensity, corresponding to the selected duration, is assumed for the whole preceding period. The reliability assessment of the proposed hyetograph is shown by schematizing the rainfall-runoff process within the catchment by means of Nash’s model while the detention basin behavior is simulated by a linear reservoir model. The proposed hyetograph can be even coupled with more sophisticated models of detention basins.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/3157
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