Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin

Understanding the link between land use/land cover (LULC) patterns and water quality can establish guidelines for non-point source pollution management and sustainable development. The transboundary Shatt Al-Arab river basin (Iraq-Iran) suffers from nutrient pollution problems. This study aimed to e...

Full description

Bibliographic Details
Main Authors: Hadi Salim Aoubid, Christian Opp
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/13/14/8376
_version_ 1797590415289876480
author Hadi Salim Aoubid
Christian Opp
author_facet Hadi Salim Aoubid
Christian Opp
author_sort Hadi Salim Aoubid
collection DOAJ
description Understanding the link between land use/land cover (LULC) patterns and water quality can establish guidelines for non-point source pollution management and sustainable development. The transboundary Shatt Al-Arab river basin (Iraq-Iran) suffers from nutrient pollution problems. This study aimed to estimate flow volume, nitrogen, and phosphorus pollution in this basin and how such pollution relates to LULC and flow volume using the Soil and Water Assessment Tool (SWAT) model. The data used in the SWAT model were the Digital Elevation Model (DEM), slope, parent materials of soil, LULC, and weather data (i.e., precipitation, relative humidity, temperature, solar radiation, and wind speed). The results showed that from 2004 to 2021, the annual Total Nitrogen (TN) and Total Phosphorus (TP) outputs were 618 and 140 kg km<sup>−2</sup>, respectively. The TN discharge load ranged from 27 to 6500 kg km<sup>−2</sup> yr<sup>−1</sup>, while the TP discharge load ranged from 1 to 1600 kg km<sup>−2</sup> yr<sup>−1</sup>. Redundancy Analysis (RDA) revealed that cropland and urban cover ratios were positively correlated with the annual TN and TP discharge loads. On the contrary, shrubland and bare land ratios were negatively correlated with the annual TN and TP discharge loads. Results showed that flow volume is positively correlated with precipitation. Both annual TN and TP discharge loads exhibited a positive correlation with flow volume and a negative correlation with subbasin area. The highest annual TN and TP discharge loads were in the middle parts of the basin, where the cultivated land and construction land are concentrated and the flow volume is high. Thus, findings suggest that the basin is sensitive to shifts in flow volume associated with global climate change and to shifts in LULC change. No study for nutrient discharge load assessment for the entire Shatt Al-Arab river basin has been performed before. Hence, the novel contribution of this study will guide the hydrologists and water resource planners in the basin to establish effective water policies, climate change mitigation strategies, and environmental change adaptation strategies.
first_indexed 2024-03-11T01:20:11Z
format Article
id doaj.art-f8d01b855f414c3893995aebc5938795
institution Directory Open Access Journal
issn 2076-3417
language English
last_indexed 2024-03-11T01:20:11Z
publishDate 2023-07-01
publisher MDPI AG
record_format Article
series Applied Sciences
spelling doaj.art-f8d01b855f414c3893995aebc59387952023-11-18T18:12:14ZengMDPI AGApplied Sciences2076-34172023-07-011314837610.3390/app13148376Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River BasinHadi Salim Aoubid0Christian Opp1Faculty of Geography, Philipps-University of Marburg, Deutschhausstr. 10, 35037 Marburg, GermanyFaculty of Geography, Philipps-University of Marburg, Deutschhausstr. 10, 35037 Marburg, GermanyUnderstanding the link between land use/land cover (LULC) patterns and water quality can establish guidelines for non-point source pollution management and sustainable development. The transboundary Shatt Al-Arab river basin (Iraq-Iran) suffers from nutrient pollution problems. This study aimed to estimate flow volume, nitrogen, and phosphorus pollution in this basin and how such pollution relates to LULC and flow volume using the Soil and Water Assessment Tool (SWAT) model. The data used in the SWAT model were the Digital Elevation Model (DEM), slope, parent materials of soil, LULC, and weather data (i.e., precipitation, relative humidity, temperature, solar radiation, and wind speed). The results showed that from 2004 to 2021, the annual Total Nitrogen (TN) and Total Phosphorus (TP) outputs were 618 and 140 kg km<sup>−2</sup>, respectively. The TN discharge load ranged from 27 to 6500 kg km<sup>−2</sup> yr<sup>−1</sup>, while the TP discharge load ranged from 1 to 1600 kg km<sup>−2</sup> yr<sup>−1</sup>. Redundancy Analysis (RDA) revealed that cropland and urban cover ratios were positively correlated with the annual TN and TP discharge loads. On the contrary, shrubland and bare land ratios were negatively correlated with the annual TN and TP discharge loads. Results showed that flow volume is positively correlated with precipitation. Both annual TN and TP discharge loads exhibited a positive correlation with flow volume and a negative correlation with subbasin area. The highest annual TN and TP discharge loads were in the middle parts of the basin, where the cultivated land and construction land are concentrated and the flow volume is high. Thus, findings suggest that the basin is sensitive to shifts in flow volume associated with global climate change and to shifts in LULC change. No study for nutrient discharge load assessment for the entire Shatt Al-Arab river basin has been performed before. Hence, the novel contribution of this study will guide the hydrologists and water resource planners in the basin to establish effective water policies, climate change mitigation strategies, and environmental change adaptation strategies.https://www.mdpi.com/2076-3417/13/14/8376land use/land coverwater qualitySWAT modelredundancy analysisShatt Al-Arab river basin
spellingShingle Hadi Salim Aoubid
Christian Opp
Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
Applied Sciences
land use/land cover
water quality
SWAT model
redundancy analysis
Shatt Al-Arab river basin
title Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
title_full Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
title_fullStr Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
title_full_unstemmed Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
title_short Nitrogen and Phosphorus Discharge Loads Assessment Using the SWAT Model: A Case Study of the Shatt Al-Arab River Basin
title_sort nitrogen and phosphorus discharge loads assessment using the swat model a case study of the shatt al arab river basin
topic land use/land cover
water quality
SWAT model
redundancy analysis
Shatt Al-Arab river basin
url https://www.mdpi.com/2076-3417/13/14/8376
work_keys_str_mv AT hadisalimaoubid nitrogenandphosphorusdischargeloadsassessmentusingtheswatmodelacasestudyoftheshattalarabriverbasin
AT christianopp nitrogenandphosphorusdischargeloadsassessmentusingtheswatmodelacasestudyoftheshattalarabriverbasin