title: Evaluation of hydraulic performance indices for retention ponds.
abstract: Comprehensive hydraulic analysis of sediment retention ponds is commonly achieved through interpretation of residence time distribution and derivation of indices associated with short-circuiting and mixing. However, the availability of various indices indicates the need for careful selection of the most appropriate indices. This study compares some of the commonly used hydraulic performance indices, together with a new short-circuiting index, τ5, for five different flow regimes in a model sediment retention pond. The results show that τ5 was the best measure for short-circuiting. Among the mixing indices, only the Morril index correctly represented the physical behaviour of the experiments. In addition, two hydraulic efficiency indices, λ and a moment index (MI) were assessed and showed a good correlation with the short-circuiting and mixing indices, but MI was more reproducible than λ. Based on these results, this study recommends using τ5, Morril index and MI for analysis of hydraulic performance in sediment retention ponds.
authors.affiliation: Department of Civil and Environmental Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand E-mail: afar797@aucklanduni.ac.nz.
authors.forename: Arash
authors.initials: A
authors.lastname: Farjood
authors.affiliation: Department of Civil and Environmental Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand E-mail: afar797@aucklanduni.ac.nz.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Melville
authors.affiliation: Department of Civil and Environmental Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand E-mail: afar797@aucklanduni.ac.nz.
authors.forename: Asaad Y
authors.initials: AY
authors.lastname: Shamseldin
authors.affiliation: Department of Civil and Environmental Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand E-mail: afar797@aucklanduni.ac.nz.
authors.forename: Keith N
authors.initials: KN
authors.lastname: Adams
authors.affiliation: Beca Ltd New Zealand, 410 Colombo Street, Sydenham, Christchurch 8023, New Zealand.
authors.forename: Sher
authors.initials: S
authors.lastname: Khan
mesh_terms: D057446:Hydrodynamics; D008962:Models, Theoretical; D061005:Ponds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D062065:Wastewater