scholarly journals Sustainable Management of Sediment Retention Ponds to Mitigate Degradation of Coastal Fisheries and Ecosystem: The Case of Ishigaki Island, Okinawa, Japan

2021 ◽  
Vol 57 (2) ◽  
pp. 38-45
Author(s):  
Shigekazu Kawashima
Keyword(s):  
Sustainable Management ◽  
Sediment Retention ◽  
Coastal Fisheries ◽  
Ishigaki Island ◽  
Retention Ponds ◽  
Sediment Retention Ponds

Evaluation of hydraulic performance indices for retention ponds

2015 ◽  
Vol 72 (1) ◽  
pp. 10-21 ◽  
Author(s):  
Arash Farjood ◽  
Bruce W. Melville ◽  
Asaad Y. Shamseldin ◽  
Keith N. Adams ◽  
Sher Khan
Keyword(s):  
Hydraulic Performance ◽  
Hydraulic Efficiency ◽  
Hydraulic Analysis ◽  
Performance Indices ◽  
Sediment Retention ◽  
Retention Pond ◽  
Retention Ponds ◽  
Sediment Retention Ponds ◽  
Moment Index ◽  
Selection Of

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.

scholarly journals Experimental investigation of the effect of temperature differentials on hydraulic performance and flow pattern of a sediment retention pond

2018 ◽  
Vol 77 (12) ◽  
pp. 2896-2906 ◽  
Author(s):  
Ehsan Hendi ◽  
Asaad Y. Shamseldin ◽  
Bruce W. Melville ◽  
Stuart E. Norris
Keyword(s):  
Residence Time ◽  
Hydraulic Performance ◽  
Effect Of Temperature ◽  
Sediment Retention ◽  
Small Temperature ◽  
Thermally Induced ◽  
Retention Pond ◽  
Retention Ponds ◽  
Sediment Retention Ponds ◽  
Counter Current

Abstract Existing studies on sediment retention ponds (SRPs) have examined the effects of pond layout, inlet and outlet geometry and the installation of baffles on the performance of the SRPs. However, the effects of a temperature difference between the ambient water in the pond and the inflow are often neglected, and the buoyancy forces arising from these differences in temperature can potentially change the flow in the pond and hence its hydraulic performance. This study has experimentally evaluated the effect of these temperature differences on the flow field and residence time in a retention pond for a range of temperature differences. As expected a cold inflow sinks to the bottom of the pond while a hot inflow remains at the surface, but in both cases the inflow flows more rapidly towards the outlet than is the case for isothermal inflow. A counter-current was observed at the bottom or the surface of the pond for colder or hotter influents, respectively. These thermally induced flows significantly reduced the residence time of the pond, reducing the hydraulic performance of the pond and causing severe short-circuiting. The results have also shown that the temperature differences in the pond decrease with time, yet small temperature differences persist with the pond remaining thermally stratified.

A study in hydraulic performance indices for Sediment Retention Ponds

2014 ◽  
pp. 251-257 ◽  
Author(s):  
Arash Farjood ◽  
Bruce Melville ◽  
Asaad Shamseldin
Keyword(s):  
Hydraulic Performance ◽  
Performance Indices ◽  
Sediment Retention ◽  
Retention Ponds ◽  
Sediment Retention Ponds

scholarly journals Effect of baffles on the hydraulic performance of sediment retention ponds

2016 ◽  
Vol 75 (9) ◽  
pp. 1991-1996
Author(s):  
Sher Khan ◽  
Bruce W. Melville ◽  
Mudasser Muneer Khan ◽  
Muhammad Shoaib ◽  
Asaad Shamseldin
Keyword(s):  
Physical Model ◽  
Residence Time ◽  
Hydraulic Performance ◽  
Large Area ◽  
Sediment Retention ◽  
Retention Pond ◽  
Retention Ponds ◽  
Sediment Retention Ponds

An investigation of the effect of baffles on retention pond performance using a physical model of an existing sediment retention pond is presented. Analysis of residence time (RTD curves) was used to compare the hydraulic performance of different arrangements of baffles in the pond. Five different arrangements for the design of baffles were studied. The results show that placing a single baffle to deflect the influent to a sediment retention pond does not improve pond performance; rather, it stimulates short-circuiting. This is contradictory to the literature and is considered to be a consequence of the model pond incorporating sloping walls, which is a novel aspect of this study. Most of the previous studies have neglected the effects of battered walls. Conversely, the inclusion of more than two baffles was found to increase the hydraulic performance. The results reported here are limited to small and narrow ponds where a large portion of the pond is batter (i.e. made up of sloping walls). For large area ponds, batter effects may be negligible and are likely to be different from those reported here.

Reducing Unintended Consequences of Agricultural Phosphorus

2019 ◽  
Vol 103 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Don Flaten ◽  
Andrew Sharpley ◽  
Helen Jarvie ◽  
Peter Kleinman
Keyword(s):  
Sustainable Management ◽  
Unintended Consequences ◽  
Valuable Resource

This article reflects upon the challenges we face in agricultural P management and provides a discussion about opportunities to promote more comprehensive and sustainable management of this valuable resource.

Risk-based land management - a concept for the sustainable management of contaminated land

2003 ◽  
Vol 11 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Joop Vegter ◽  
Judith Lowe ◽  
Harald Kasamas
Keyword(s):  
Land Management ◽  
Sustainable Management ◽  
Contaminated Land
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