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University of Western Australia (2012)

Spatial and temporal variations and patterns in water and nutrient dynamics within agriculturally-dominated watersheds in South West Australia

Rivers, Mark Robert

Titre : Spatial and temporal variations and patterns in water and nutrient dynamics within agriculturally-dominated watersheds in South West Australia

Auteur : Rivers, Mark Robert

Université de soutenance : University of Western Australia

Grade : Doctor of Philosophy (PhD) 2012

Résumé
[Truncated abstract] The issue of nutrient loss to waterways and the subsequent issues of algal blooms and other water quality problems are generally well studied and understood, but there are still two major disconnects. There is still poor understanding of : the links between farmscale actions and watershed-scale response, and ; the relationships between water quality measurements taken at different scales within a watershed. How do farm decisions affect downstream water quality, and what do measurements at one scale tell us about effects at another scale ? This thesis clarifies these issues through a series of water quality monitoring programmes undertaken in South Western Australia at scales ranging from paddockscale to watershed scale and in watersheds with a variety of agricultural land uses. The findings, together with additional research work, are then applied to a systems dynamics model of water and phosphorus (P) movement through a watershed to determine the water quality impacts that can realistically be expected under a range of watershedmanagement scenarios over a variety of timeframes. Water quality data from a series of trials at irrigated and dryland farms and watersheds which cover a broad range of land use, soil type, farming intensity and, importantly, scale of measurement has been analysed. Through an analysis of the combined dataset of the individual trials, it is now possible to propose some over-arching relationships between water quality signals and scale of measurement – albeit with some major qualifications to general relationships based on gross factors such as land use. Robust statistical relationships have been developed between scale of m

Mots clés : Catchment management ; System dynamics ; Environmental modelling ; Phosphorus ; Eutrophication

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Page publiée le 18 juin 2013, mise à jour le 4 juillet 2017