River health assessment in peri-urban landscapes: an application of multivariate analysis to identify the key variables.

An array of river health assessment approaches and water quality variables have been suggested in the past for assessing the level of river health. However, the selection of suitable variables to be monitored for the assessment remains ambiguous and often it is not practical to monitor all the suggested variables. In this study, we employ a multivariate data reduction technique, called Factor Analysis (FA), to identify the key river health variables for a peri-urban river system, viz., the Hawkesbury-Nepean River system in New South Wales, Australia. Out of 40 water quality variables included in the analysis, the FA identified nine key variables, under three varifactors (VFs), explaining 50% of the variance in the river water quality. Variables in the first, second and third VFs revealed anaerobic conditions, microbial quality and effects of eutrophication in the Hawkesbury-Nepean River. Thus, the present work shows a notable reduction in the number of variables and the application of FA for identification of key variables was found promising. The finding of this study has potential application in designing a cost-effective river health monitoring program by reducing the number of variables to be monitored in a peri-urban situation. It can also assist in partitioning variables according to their unique contribution to the total variance.

[1]  R. E. Turner,et al.  Linking Landscape and Water Quality in the Mississippi River Basin for 200 Years , 2003 .

[2]  Basant Maheshwari,et al.  Reuse of greywater for irrigation around homes in Australia: Understanding community views, issues and practices , 2010 .

[3]  K. R. Clarke,et al.  A Method Of Linking Multivariate Community Structure To Environmental Variables , 1993 .

[4]  W. Erskine,et al.  Variability in the development, persistence and breakdown of thermal, oxygen and salt stratification on regulated rivers of southeastern Australia , 2005 .

[5]  Yong Liu,et al.  Application of Multivariate Statistical Methods to Water Quality Assessment of the Watercourses in Northwestern New Territories, Hong Kong , 2006, Environmental monitoring and assessment.

[6]  S. Markich,et al.  Relative importance of natural and anthropogenic influences on the fresh surface water chemistry of the Hawkesbury-Nepean River, south-eastern Australia. , 1998, The Science of the total environment.

[7]  Xuezheng Shi,et al.  Surface water quality of factory-based and vegetable-based peri-urban areas in the Yangtze River Delta region, China , 2007 .

[8]  B. Whitton,et al.  Use of algae and other plants for monitoring rivers , 1995 .

[9]  John H. Harris,et al.  The use of fish in ecological assessments , 1995 .

[10]  Martin Krogh,et al.  Roles of land use resolution and unit-area load rates in assessment of diffuse nutrient emissions. , 2003, Journal of environmental management.

[11]  W. D. Alberto,et al.  Pattern recognition techniques for the evaluation of spatial and temporal variations in water quality. A case study: Suquía River Basin (Cordoba-Argentina). , 2001 .

[12]  A. Underwood.  On Beyond Baci: Sampling Designs That Might Reliably Detect Environmental Disturbances , 1994 .

[13]  B. Murray.  The life and times of the Enterococcus , 1990, Clinical Microbiology Reviews.

[14]  B. Chessman,et al.  Rapid assessment of rivers using macroinvertebrates: A procedure based on habitat‐specific sampling, family level identification and a biotic index , 1995 .

[15]  S. Shrestha,et al.  Assessment of surface water quality using multivariate statistical techniques: A case study of the Fuji river basin, Japan , 2007, Environ. Model. Softw..

[16]  J. Karr.  Biological Integrity: A Long-Neglected Aspect of Water Resource Management. , 1991, Ecological applications : a publication of the Ecological Society of America.

[17]  M. Huijbregts,et al.  Redefinition and Elaboration of River Ecosystem Health: Perspective for River Management , 2006 .

[18]  P. Fairweather.  State of environment indicators of ‘river health’: exploring the metaphor , 1999 .

[19]  Thomas C. Winter,et al.  The Use of Principal Component Analysis for Interpreting Ground Water Hydrographs , 2000 .

[20]  M. Parsons,et al.  The effect of habitat‐specific sampling on biological assessment of water quality using a predictive model , 1996 .

[21]  U. Kamp,et al.  River habitat monitoring and assessment in Germany , 2007, Environmental monitoring and assessment.

[22]  M. Kaika.  The Water Framework Directive: A New Directive for a Changing Social, Political and Economic European Framework , 2003 .

[23]  J. F. Wright,et al.  Development and use of a system for predicting the macroinvertebrate fauna in flowing waters , 1995 .

[24]  M. Huston.  A General Hypothesis of Species Diversity , 1979, The American Naturalist.

[25]  A. Robertson,et al.  Relationships between livestock management and the ecological condition of riparian habitats along an Australian floodplain river , 2001 .

[26]  C. Yentsch.  Distribution of chlorophyll and phaeophytin in the open ocean , 1965 .

[27]  Andrew J. Boulton,et al.  An overview of river health assessment: philosophies, practice, problems and prognosis , 1999 .

[28]  J. Connell.  Chapter 2 – Ecology: Field Experiments in Marine Ecology , 1974 .

[29]  P. Groffman,et al.  The urban stream syndrome: current knowledge and the search for a cure , 2005, Journal of the North American Benthological Society.

[30]  G. Jin,et al.  Comparison of E.Coli, Enterococci, and Fecal Coliform as Indicators for Brackish Water Quality Assessment , 2004, Water environment research : a research publication of the Water Environment Federation.

[31]  Luis Deban,et al.  Assessment of seasonal and polluting effects on the quality of river water by exploratory data analysis , 1998 .

[32]  A. Karbassi,et al.  Evaluation of spatial and seasonal variations in surface water quality using multivariate statistical techniques , 2009 .

[33]  N. Dalkey,et al.  An Experimental Application of the Delphi Method to the Use of Experts , 1963 .