Summary 1. The influence of hydraulic conditions on the spatial distribution macroinvertebrate assemblages was investigated in three riffles a perennial Australian river. 2. Velocity, depth and variability substrate roughness were measured at each 56 sampling locations. Complex variables (roughness Reynolds number, shear velocity, Froude number) calculated from combinations two or directly variables. biological significance complex determined by combination univariate multivariate...

ABSTRACT Floodplains along the braided gravel‐bed Waimakariri River are discontinuous although generally extensive landforms composed predominantly of gravel bars capped with vertically accreted fines. In order importance, three mechanisms lead to floodplain formation. bed abandonment by lateral migration braid‐train initiates formation largest floodpiains, which usually occur downstream tributary fans and valley bedrock spurs. headwater reaches, localized river aggradation during high...

Abstract Human disturbance induces significant geomorphic changes to river systems. In eastern Australia, land‐use practices such as clearance of forests and riparian vegetation, removal wood from channels in the 19th 20th centuries induced widespread impacts. However, since 1970s, there has been a noticeable shift condition many rivers New South Wales (NSW). This transition recovery trajectory reflects reduction pressures improved farming on one hand adoption enhancement approaches...

ABSTRACT The migratory response and behaviour of catadromous Australian bass with regard to hourly mean river flows water temperatures was assessed over 15 months. Fish movement using a 75‐km passive acoustic telemetry array in the regulated Shoalhaven River below Tallowa Dam, NSW, Australia. majority (62%) downstream pre‐spawning migrations from freshwater estuarine habitats were stimulated by series flow pulses April September, but proportion fish (38%) commenced under baseflow conditions...

Abstract – Understanding movement patterns and habitat utilisation is critical for the management of diadromous fishes. An acoustic telemetry array was used to monitor 33 estuary perch, Macquaria colonorum 39 Australian bass, novemaculeata in freshwater estuarine reaches on Shoalhaven River, south‐east Australia. On average, tagged M. were detected a considerably shorter period than , evidence suggested that fishing pressure may have impacted their survival. displayed significant shifts...

Physicochemical variability in estuarine systems plays an important role processes and the lifecycles of organisms. In particular, seasonality freshwater inflow to estuaries may be various aspects fish lifecycles. This study aimed further understand these relationships by studying movements a top-level predator response physicochemical large, temperate south-east Australian estuary (Shoalhaven River). Mulloway (Argyrosomus japonicus, 47–89 cm total length) were surgically implanted with...

Approximately 15% of the world’s total run-off is presently retained by more than 45 000 large dams. However, extent downstream ecological impacts those dams rarely assessed. The longitudinal effects a reservoir on substrate, water quality and riffle macroinvertebrate communities were examined between 0.5 18.3 km Tallowa Dam. number taxa Australian River Assessment Scheme observed v. expected score generally increased with increasing distance from dam, average clast size decreased showed...

Abstract Despite providing considerable benefits to society, dams and weirs threaten riverine ecosystems by disrupting movement migration of aquatic animals degrading habitats. Whilst the ecological impacts large are well studied, effects low-head that periodically drowned out high flows less well-understood. Here we examine a weir on fine- broad-scale movements, habitat use, breeding behaviour three species native freshwater fish in Nymboida River coastal eastern Australia. Acoustic...

Abstract Proposed environmental flow regime changes downstream of a major water supply dam have been assessed in terms effects on depth, velocity and fish passage across natural, gravel‐bed riffles rapids. This study focussed requirements for Australian bass, Macquaria novemaculeata (Perciformes, Percichthyidae), catadromous considerable ecological recreational fishing importance. Some 23 rapids occur between the tidal limit over river length 25 km. Reconnaissance investigations riffle...

ABSTRACT The Riverine Plain in south‐eastern Australia contains numerous palaeochannels that are much larger than the present rivers and provide evidence about past hydrological conditions. Previous research suggested optima fluvial activity both before after peak of Last Glacial Maximum (LGM; 21 ± 3 ka), and, some cases, throughout LGM. In this study, we revisit palaeochannel remnants Gum Creek Yanco systems along Murrumbidgee River, which drains high‐elevation catchments Australian Alps...

Abstract Analysis of inflections or breakpoints apparent in relationships between measures wetted perimeter and discharge can be used to assist the determination minimum environmental flows for perennial rivers. This paper suggests refinements provides an example application method cease‐to‐pump limits a perennial, unregulated gravel‐bed river subject increasing levels surface water extraction. HEC‐GeoRAS modelling outputs riffle area are illustrate that magnitude selected represent 100%...

ABSTRACT Reduced mixing of deep pools attributable to river regulation and downstream flow suppression can lead an increase in the magnitude, frequency duration thermal stratification riverine over summer. This study monitored hourly temperature profiles with five thermistor loggers a 15 m natural pool 12 months from May 2005. Detailed bathymetric topographic survey data HEC‐RAS hydraulic modelling layer Richardson numbers were used extend observations flow‐related breakdown this single 20...

River flow regimes and their variability are considered by many authors to be the most important factor structuring physical ecological environment. In regulated rivers, environmental or instream flows main management technique used ameliorate effects of alteration. We highlight two concepts that not commonly in a managed regime but help return natural river, namely, transparent translucent rules. Transparency target lower up defined threshold so all inflows released from dam protected...

Channel changes on the lower Latrobe River since late 1800s include a 25 per cent reduction in channel length due to artificial meander cutoffs, increases mean width, increased instability and incision of up 1.05 m. Hydraulic at Rosedale gauge bankfull flow velocity 67 increase capacity, resulting threefold over‐bank duration. The extensive channelisation works have reduced frequency minor flooding period offloodplain inundation, but these other human impacts severely degraded stream environment.