Algae-based models to configure consumptive flows for ecological benefit in the highly regulated MacKenzie River, south-east Australia

• Main Author: Atazadeh, Ehsan
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: Federation University Australia 2017
• Subjects: MacKenzie River; Australia; River ecosystems; Mackenzie River; Mackenzie river
• Online Access: http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/162587; https://library.federation.edu.au/record=b2746497

Many river ecosystems, especially those in arid and semi-arid, are experiencing severe stress due to the increasing demands on the ecosystem services they provide, coupled with anthropogenic catchment impacts and factors associated with climate change and weather extremes. The flow regime of the Mackenzie River was substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is now regulated at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. The river receives an environmental flow allocation and the river channel is used to transfer water dedicated for consumptive use. Water Quality and algal monitoring formed the basis of models that were developed evaluate the ecological condition of this working river under base flow and before, during and after freshes that deliver water to users. Samples of diatoms, soft algae and measurements of water quality were analysed at ten sampling sites for three years (between February 2012 and November 2014) along the MacKenzie River in different seasons and under different flow regimes to understand the spatial and temporal variation in the relationship between algal communities and water quality, and so stream condition. Baseline information on algal communities and water quality was collected during base flow conditions, while experiments on the effect of water releases on algal communities were based on flow regime variations (manipulated flow regimes), specifically on the algae community structure, water quality and ecosystem function. These comprised cease to flow (0 ML/day), low flows (10-15 ML/day), freshes (35-40 ML/day) and high flow (55ML/day) conditions. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, phosphorus and cations and anions were measured. Biological properties of the algal periphyton communities, including dry mass, ...