Multi-Scale Analysis of the Dependence of Water Quality on Land Use Using Linear and Mixed Models

Johann Alexander Vera Mercado,Bernard Engel

doi:10.3390/w13192618

Abstract

Land use influences water quality in streams at different spatial scales and varies in time and space. Water quality has long been associated with agricultural and urban land uses in catchments. The effects of developed, forest, pasture, and agricultural land use on nitrogen, nitrate, and nitrite (NNN); total phosphorus (TP); total suspended solids (TSS); chemical oxygen demand (COD); dissolved oxygen (DO) and total Kjeldahl nitrogen (TKN) concentrations and their sensitivity were quantified to spatial pattern differences. The linear mixed modeling framework was used to examine the importance of spatial extent on models with water quality parameters as the response variable and land use types as the predictor variable. The results indicated that land use categories on different water quality parameters were significant and dependent on the selected spatial scales. Land use exhibited a strong association with total phosphorus and total suspended solids for close reach distances. Phosphorus is not highly soluble, and it binds strongly to fine soil particles, which are transported by water via runoff. Nitrogen, nitrate, and nitrite, dissolved oxygen, chemical oxygen demand, and total Kjeldahl nitrogen concentrations were better predicted for further reach distances, such as 45 or 50 km, where the best model of nitrogen, nitrate, and nitrite is consistent with the high mobility of NO3−.

Highlights

The quality of water supply is usually related to land use within a catchment area as it determines the quality and quantity of runoff before and after a rainfall event [1]
Cultivated crops account for 79.76% of land uses inside of the Wabash Basin mostly for corn and soybean, 8.88% are developed areas in general, 6.14% are forest, and pasture constitutes only 2.96% of the sub-basin average areas in 2001 (Table 1)
This study showed that for developed and pasture land use percentages, there is not much difference among study watershed reach distances

Summary

Introduction

The quality of water supply is usually related to land use within a catchment area as it determines the quality and quantity of runoff before and after a rainfall event [1]. The main factors behind the alteration of the hydrological system are changes in land cover and land management practices, causing changes in runoff as well as the quality of receiving water [2,3]. Watershed factors, such as land use, landscape, and physiographical characteristics, may have a direct impact on the quality of river water [4,5]. Changing land use and land management practices are regarded as central factors in altering the hydrological system, causing changes in runoff and water quality [7]

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Results

Conclusion