Loading…

Assessing the impacts of land use on downstream water quality using a hydrologically sensitive area concept

Understanding the relationship between land use and water quality is essential to improve water quality through carefully managing landscape change. This study applies a linear mixed model at both watershed and hydrologically sensitive areas (HSAs) scales to assess such a relationship in 28 northcen...

Full description

Saved in:
Bibliographic Details
Published in:Journal of environmental management 2018-05, Vol.213, p.309-319
Main Authors: Giri, Subhasis, Qiu, Zeyuan, Zhang, Zhen
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Understanding the relationship between land use and water quality is essential to improve water quality through carefully managing landscape change. This study applies a linear mixed model at both watershed and hydrologically sensitive areas (HSAs) scales to assess such a relationship in 28 northcentral New Jersey watersheds located in a rapidly urbanizing region in the United States. Two models differ in terms of the geographic scope used to derive land use matrices that quantify land use conditions. The land use matrices at the watershed and HSAs scales represent the land use conditions in these watersheds and their HSAs, respectively. HSAs are the hydrological “hotspots” in a watershed that are prone to runoff generation during storm events. HSAs are derived using a soil topographic index (STI) that predicts hydrological sensitivity of a landscape based on a variable source area hydrology concept. The water quality indicators in these models are total nitrogen (TN), total phosphorus (TP) and total suspended solids (TSS) concentrations in streams observed at the watershed outlets. The modeling results suggest that presence of low density urban land, agricultural land and wetlands elevate while forest decreases TN, TP and/or TSS concentrations in streams. The watershed scale model tends to emphasize the role of agricultural lands in water quality degradation while the HSA scale model highlights the role of forest in water quality improvement. This study supports the hypothesis that even though HSAs are relatively smaller area compared to watershed, still the land uses within HSAs have similar impacts on downstream water quality as the land uses in entire watersheds, since both models have negligible differences in model evaluation parameters. Inclusion of HSAs brings an interesting perspective to understand the dynamic relationships between land use and water quality. [Display omitted] •A novel approach for comparing the impacts of land use on water quality both at watershed and HSAs scales.•Low density urban, agriculture, and wetlands degrade while forest enhances water quality in streams.•At the watershed scale, the role of agriculture in water quality degradation is more emphasized.•At the HSA scale, the role of forest in water quality improvement is more highlighted.•Land uses in smaller HSAs have similar impacts on water quality as in the entire watershed.
ISSN:0301-4797
1095-8630
DOI:10.1016/j.jenvman.2018.02.075