The effect of vegetation and soil texture on the nature of organics in runoff from a catchment supplying water for domestic consumption

John Awad; John van Leeuwen; Dawit Abate; Markus Pichler; Erick Bestland; David J Chittleborough; Nigel Fleming; Jonathan Cohen; Joel Liffner; Mary Drikas

doi:10.1016/j.scitotenv.2015.05.037

The effect of vegetation and soil texture on the nature of organics in runoff from a catchment supplying water for domestic consumption

Sci Total Environ. 2015 Oct 1:529:72-81. doi: 10.1016/j.scitotenv.2015.05.037. Epub 2015 May 22.

Authors

Affiliations

¹ Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, South Australia 5095, Australia.
² Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, South Australia 5095, Australia; State Key Laboratory for Environmental Aquatic Chemistry, CAS, Beijing, China; Barbara Hardy Institute, University of South Australia, South Australia 5095, Australia. Electronic address: John.VanLeeuwen@unisa.edu.au.
³ School of the Environment, Flinders University, Bedford Park, South Australia 5042, Australia.
⁴ School of Physical Sciences, University of Adelaide, North Terrace, South Australia 5005, Australia.
⁵ South Australian Research and Development Institute, P.O. Box 397, Adelaide, SA 5000, Australia.
⁶ Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, South Australia 5095, Australia; Australian Water Quality Centre, SA Water Corporation, 250 Victoria Square, Adelaide, South Australia 5000, Australia; State Key Laboratory for Environmental Aquatic Chemistry, CAS, Beijing, China.

PMID: 26005751
DOI: 10.1016/j.scitotenv.2015.05.037

Abstract

The influence of vegetation and soil texture on the concentration and character of dissolved organic matter (DOM) present in runoff from the surface and sub-surface of zero order catchments of the Myponga Reservoir-catchment (South Australia) was investigated to determine the impacts of catchment characteristics and land management practices on the quality of waters used for domestic supply. Catchments selected have distinct vegetative cover (grass, native vegetation or pine) and contrasting texture of the surface soil horizon (sand or clay loam/clay). Water samples were collected from three slope positions (upper, middle, and lower) at soil depths of ~30 cm and ~60 cm in addition to overland flows. Filtered (0.45 μm) water samples were analyzed for dissolved organic carbon (DOC) and UV-visible absorbance and by F-EEM and HPSEC with UV and fluorescence detection to characterize the DOM. Surface and sub-surface runoff from catchments with clay soils and native vegetation or grass had lower DOC concentrations and lower relative abundances of aromatic, humic-like and high molecular weight organics than runoff from sandy soils with these vegetative types. Sub-surface flows from two catchments with Pinus radiata had similar DOC concentrations and DOM character, regardless of marked variation in surface soil texture. Runoff from catchments under native vegetation and grass on clay soils resulted in lower DOC concentrations and hence would be expected to have lower coagulant demand in conventional treatment for potable water supply than runoff from corresponding sandy soil catchments. However, organics in runoff from clay catchments would be more difficult to remove by coagulation. Surface waters from the native vegetation and grass catchments were generally found to have higher relative abundance of organic compounds amenable to removal by coagulation compared with sub-surface waters. Biophysical and land management practices combine to have a marked influence on the quality of source water used for domestic supply.

Keywords: Fluorescence-EEM; Land use; Molecular weight; Organic carbon; Sub-surface flow; Surface runoff.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Environmental Monitoring*
Models, Chemical
Plants / chemistry*
Soil / chemistry*
South Australia
Water Movements
Water Pollutants / analysis*
Water Supply

Substances

Soil
Water Pollutants