Hydrochemical indices as a proxy for assessing land‑use impacts on water resources: a sustainable management perspective and case study of Can Tho City, Vietnam

In Natural Hazards
Peer-reviewed Article
cover image

Can Tho City is experiencing water stress driven by rapid global changes. This study
assesses the spatiotemporal variation in surface water quality (SWQ) through a multivariate
statistical approach to provide evidence-based scientific information supporting sustainable
water resource management and contributing to achieving the city’s sustainable development
goals (SDGs). The complex SWQ dataset with 14 monthly-measured parameters
at 73 sampling sites throughout the city was collected and analyzed. The obtained results
indicated that average concentrations of biochemical oxygen demand, chemical oxygen demand (COD), dissolved oxygen (DO), total coliform, turbidity, total suspended solids,
and phosphate (
3−) exceeded the permissible national levels. Spatially, cluster analysis
had divided the city’s river basin into three different zones (mixed urban-industrial,
agricultural, and mixed urban–rural zones). The key sources of SWQ pollution in these
three zones were individually identified by principal component/factor analysis (PCA/FA),
which were mainly related to domestic wastewater, industrial effluents, farming runoff, soil
erosion, upstream sediment flows, and severe droughts. Discriminant analysis also explored
that COD, DO, turbidity, nitrate (
−), and PO4
3− were the key parameters discriminating
SWQ in the city among seasons and land-use zones. The temporally analyzed results
from weighted arithmetic water quality index (WAWQI) estimation revealed the deterioration
of SWQ conditions, whereby the total polluted monitoring sites of the city increased
from 29% in 2013 to 51% in 2019. The key drivers of this deterioration were the expansion
in built-up and industrial land areas, farming runoff, and droughts.

Nguyen Hong
Pham Phuong
Tonni Agustiono
Khaled Mohamed