Instream habitat and minimum flow requirements in the middle and lower Oreti River [eletronic resoruce] / Ian G. Jowett.

By: Jowett, Ian G.
Contributor(s): Environment Southland.
Material type: materialTypeLabelBookSeries: Client Report ; IJ0903.Publisher: [Invercargill, N.Z.] : Environment Southland, 2009Description: 47 p. : ill., map ; 30 cm.Subject(s): STREAMS | RIVERS | AQUATIC HABITATS | FRESHWATER FISH | HYDROLOGY | HABITATS | FLOW RATES | LOW FLOWS | TROUT | BROWN TROUT | EELS | LONGFINNED EELS | SHORTFINNED EELS | TORRENTFISH | BLUEGILLED BULLY | INANGA | BULLIES | COMMON BULLY | REDFINNED BULLY | ZELANDOPERLA | STONEFLIES | DELEATIDIUM | MAYFLIES | PYCNOCENTRODES | OLINGA FEREDAYI | SERICOSTOMATIDAE | AOTEAPSYCHE | HYDROBIOSIDAE | COLOBURISCUS HUMERALIS | MAORIDIAMESA | DIPTERA | APHROPHILA | CADDIS FLIES | SURVEYS | ORETI RIVER | SOUTHLAND | NEW ZEALANDHoldings: Index record. Online resources: Click here to access online Abstract: The purpose of this study was to investigate the flows required to maintain acceptable habitat for native fish and trout in the middle and lower reaches of Oreti River. The selection of appropriate minimum flows for fish is a compromise between the contrasting requirements of the different species. For example, upland bullies prefer low velocity water and thus require relatively low flows, whereas trout, especially adult trout, prefer moderate water velocities and require reasonably high flows. Thus, the selection of an appropriate minimum flow depends on the fish species present and flow management objectives that balance the degree of environmental protection against the value of water for other uses. The levels of environmental protection, in terms of habitat retention at the minimum flow, are set out in Environment Southlandgass Proposed Regional Water Plan for Southland. These are expressed as a percentage of habitat at the 7-day mean annual low flow (7-day MALF), or a proportion of maximum habitat if it occurs at a flow less than the mean annual low flow. The Oreti River is a high quality trout fishery and the appropriate standard would be to set a minimum flow that maintains 90% of adult brown trout habitat. The middle reaches of the Oreti River are between Mossburn and a point about 3 km north of Dipton and are mainly multi-channel. A reach at Ram Hill about 12 km below the Lumsden cableway water level recorder was selected by Environment Southland as representing the multi-channel character of the middle Oreti. Below Dipton, the river is mainly in a single channel and existing instream habitat surveys at Centre Bush and Branxholme were used to represent this section of river. ... - Executive summary
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Bibliographic references (p. 33-35)

The purpose of this study was to investigate the flows required to maintain acceptable habitat for native fish and trout in the middle and lower reaches of Oreti River. The selection of appropriate minimum flows for fish is a compromise between the contrasting requirements of the different species. For example, upland bullies prefer low velocity water and thus require relatively low flows, whereas trout, especially adult trout, prefer moderate water velocities and require reasonably high flows. Thus, the selection of an appropriate minimum flow depends on the fish species present and flow management objectives that balance the degree of environmental protection against the value of water for other uses. The levels of environmental protection, in terms of habitat retention at the minimum flow, are set out in Environment Southlandgass Proposed Regional Water Plan for Southland. These are expressed as a percentage of habitat at the 7-day mean annual low flow (7-day MALF), or a proportion of maximum habitat if it occurs at a flow less than the mean annual low flow. The Oreti River is a high quality trout fishery and the appropriate standard would be to set a minimum flow that maintains 90% of adult brown trout habitat. The middle reaches of the Oreti River are between Mossburn and a point about 3 km north of Dipton and are mainly multi-channel. A reach at Ram Hill about 12 km below the Lumsden cableway water level recorder was selected by Environment Southland as representing the multi-channel character of the middle Oreti. Below Dipton, the river is mainly in a single channel and existing instream habitat surveys at Centre Bush and Branxholme were used to represent this section of river. ... - Executive summary

Index record.

No Record on TP 9/12/9 MG

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