Abstract:
Ecological and statistical models were developed using freshwater algal assemblages to assess water quality and ecological health of a regulated river. These models were used to inform configuration of flows to maintain or improve environmental conditions of the waterway whilst meeting consumptive water supply commitments. The flow regime of the MacKenzie River, western Victoria, Australia, has been substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is withdrawn at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. To assess the impact of the different flow regimes on river health and ecosystem function, ten sites were repeatedly sampled along the river between February 2012 and April 2014. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, total phosphorous, cations, and anions, were measured. Biological properties of the algal periphyton communities, including dry mass, ash-free dry mass, chlorophyll-a concentration, and species composition, were also measured. Exploration of the algal assemblage and water chemistry data using the computationally unconstrained ordination technique such as principal component analysis principal component analysis (PCA), correspondence analysis (CA), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA) indicated two strong gradients in the data sets. Furthermore, the quantitative ecosystem response models have been developed as the prototype tool to assist in the future configuration of flows in this river. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 ML/day, as indicated by the reduction in green algae and cyanobacteria and improvement. Finally, the results are presented to tailor discharge and duration of water volume by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes.
摘要:
使用淡水藻类组合开发了生态和统计模型,以评估受管制河流的水质和生态健康。这些模型用于告知流量配置,以维持或改善水道的环境条件,同时满足消耗性供水承诺。麦肯齐河的流态,维多利亚西部,澳大利亚,自从1887年在其上游建造了一个供水水库以来,已经进行了实质性的修改。在水库下游的几个位置取水。创建一个大幅修改的流动状态,影响河流的关键环境价值。为了评估不同流态对河流健康和生态系统功能的影响,在2012年2月至2014年4月期间,沿河重复采样了10个地点。水的物理和化学特性,包括pH值,温度,浊度,电导率,溶解氧,总氮,总磷,阳离子,和阴离子,被测量。藻类附生群落的生物学特性,包括干重,无灰干质量,叶绿素a浓度,和物种组成,也被测量了。使用主成分分析主成分分析(PCA)等计算无约束排序技术探索藻类组合和水化学数据,对应分析(CA),去趋势对应分析(DCA),和规范对应分析(CCA)指示数据集中的两个强梯度。此外,定量生态系统响应模型已被开发为原型工具,以协助该河流未来的流量配置。经验数据和模型表明,在低流量下,河流下游处于恶劣状态,但是这种情况在35毫升/天的流量下有所改善,绿藻和蓝藻的减少和改善表明。最后,结果是通过消耗和环境流量的合并来调整水量的排放和持续时间,以改善河流的状况,从而补充专用于环境结果的流量。