How Do Terrestrial Determinants Impact the Response of Water Quality to Climate Drivers?—An Elasticity Perspective on the Water–Land–Climate Nexus

Abstract

Investigating water-land-climate interactions is critical for urban development and watershed management. This study examined this nexus by elasticity and statistical approaches through the lens of three watersheds: The Yukon, Mekong and Murray. Here, this study reports the fundamental characteristics, explanations and ecological and management implications of terrestrial determinant influence on the response of water quality to climate drivers. The stability of the response, measured by climate elasticity of water quality (CEWQ), is highly dependent on terrestrial determinants, with strong impacts from anthropogenic biomes and low impacts from surficial geology. Compared to temperature elasticity, precipitation elasticity of water quality is more unstable due to its possible linkages with many terrestrial determinants. Correlation and linear models were developed for the interaction system, which uncovered many interesting scenarios. The results implied that watersheds with a higher ratio of rangeland biomes have a lower risk of instability as compared to watersheds with a higher proportion of dense settlement, cropland and forested biomes. This study discusses some of the most essential pathways where instability might adversely affect CEWQ parameters and recommends suggestions for policy makers to alleviate the instability impacts to bring sustainability to the water environment.

Complex Linkage between Watershed Attributes and Surface Water Quality: Gaining Insight via Path Analysis

“…GDP is positively linked with riverine NO3 concentration which may be due to urbanization and agriculture activities in Indus basin. Economic growth enhances urban development and agriculture activities where domestic sewage and irrigation tail water discharges enhance riverine NO3 concentration [22]. This study indicates that streams in this landscape will obtain more contaminants from anthropogenic activities [40][41][42].…”

“…Conservation of rangelands at watershed scale can help to protect ecosystem health. Riverine flow regime has negative correlation with EC which might be due to dilution effects [22]. Moreover, 2/3 climate models demonstrated that annual average runoff would increase in future [17].…”

“…Mean population has negative linkage with rangelands because rangelands are thinly populated areas. Rangelands are negatively associated with riverine flow regime which may be due to high infiltration owing to its pervious surface area [22,[25][26][27]. Basin having higher ration of rangelands decline pollutants load in surface waters owing to lower elasticity value and higher pollutants retention capability.…”

“…Precipitation and irrigation tail water discharges fuel the problem of water quality impairment from nonpoint sources of croplands [19]. NH4-F and NOX-F have strong correlation with cropland biomes [22]. Literature shows that agriculture lands enhance nutrients concentration in surface water bodies which is mainly attributed to irrigation tail water discharges and precipitation overland flow which sweeps all kinds of pollutants especially fertilizer remaining's from the top fertile soil layer to nearby water bodies [5,23].…”

Assessment of the Impacts of Terrestrial Determinants on Surface Water Quality at Multiple Spatial Scales

“…LULC, topographical condition, soil texture and other climatic conditions are mainly responsible for the transport of pollutants at catchment scale [2,3]. Hence, watershed managers are constantly seeking the relationship between various water quality parameters and the aforementioned determinants which is a challenging task [4]. It is also necessary to adopt multiple spatial scale analysis to determine the sink/source relationship.…”