High efficiency sediment basins

High efficiency sediment basins — Planning and design

Select from the tabs below

• Overview
• Key considerations
• Planning and design
• Construction and operation
• Links and references

Sizing

The HES basin needs to be large enough to allow for a 1 hour residence time. The dimensions of the recycle pit will need to be tailored to the site[1].

Conversion of rainfall figures to run-off volumes may require expert input and/or hydrological modelling to ensure the HES basin is sized appropriately[2]

Footprint 2-3% of contributing catchment

Site selection

HES basins need to be located in a suitable part of the farm, connected to the drainage network so that it can receive runoff from an appropriate area of the farm.

• Off-line from major flow paths.
• Immediately upstream of drainage/irrigation water discharge points from property (farm).
• Existing irrigation tailwater ‘recycle pits’ or sediment basins
• At drainage and irrigation collection points immediately downslope of land in fallow.

Design requirements

• HES basins should be located off-line from major stream/river flows.
• The size of the basin should be designed relative to the local climatic conditions and irrigation/ drainage regime to treat the design stormwater event flows and irrigation water generated from the local connected catchment (catchments typically up to a maximum of 100ha)[1][2].
• Bypass excess flows with minimal mixing.
• Automated coagulant dosing requires a power source
• Regular removal of accumulated sediment

References

1. ^ a b Eadie, M (June 2016), 'High Efficiency Sediment Basins for Reef Catchment Applications', Treatment Systems in Coastal Catchments Forum. [online] Available at: https://wetlandinfo.des.qld.gov.au/wetlands/management/treatment-systems/for-agriculture/treatment-sys-nav-page/treatment-forum/.
2. ^ a b Robson, K (2015), An assessment of the performance of current best practice sediment basins vs. high efficiency sediment basins based on modelling and field studies, Stormwater Queensland, Toowoomba.

Last updated: 10 June 2022