Modelling the effects of urbanization on nutrients pollution for prospective management of a tropical watershed: A case study of Skudai River watershed
Introduction
The level of nutrient pollution produced from the urban areas is among the leading causes of stream impairment in most urbanized watersheds (Duan et al., 2012, Edwards, 2016, Li et al., 2017). For example, the conversion of vegetative and wetland areas to impervious surfaces (buildings, roads, etc.) changes the hydrologic regimes, ecosystem distribution, and nutrient dynamics (Hogan et al., 2014; Bhaskar et al., 2016). The impervious surface amplifies runoff volumes and increases transport of nutrient pollutants from areas of non-point sources (NPSs). These changes adversely affect the water quality and aquatic habitat, their functions in stream ecosystems (Rafferty et al., 2013).
Urban development affects the environment (Netusil et al., 2014; Gashi et al., 2016), and therefore evaluating its influence on the nutrient dynamics will provide useful information on how to protect the environment and ensure human safety (Shen et al., 2015). There are relatively few studies on effects of urbanization in humid tropical regions. Humid tropic regions are characterised with extreme weather conditions (more rainfall and high temperatures) as compared to temperate climates (Ghaffarianhoseini et al., 2019; Ayoub et al., 2020). Depending on the land-use type, the tendency for excessive sediment and nutrient pollution entering the rivers will be more severe (Abd Wahaba et al. 2019). Land-use is a driver of nutrient pollutants and thus important to be considered in urban planning and watershed management and hence, the amount of nutrient pollutants produced due to sudden or gradual urban expansion can be readily determined and applied to support the management of water quality in urbanized settings (Bello et al., 2019). Therefore, understanding the impact of urban development on nutrient pollutants at watershed scale in a tropical region like Malaysia is very important. According to Sala (2000), the effects of land-use changes on the water cycle may outweigh those associated with climate change, and this assertion was supported by a study conducted in Puget Sound Basin (Sun et al., 2016). The result shows that urbanization has a much larger effect than climate change on both the magnitude and the seasonal variability in the studied area. As observed by Tang et al. (2011) and Lee et al. (2017), rapid urbanization is directly associated with an increase in excess nutrients in Malaysia and hence changes in characteristics of the watersheds over a period due to human activities should be considered for water quality improvement. This will help in determining the impact of the potential anthropogenic activities and mitigation actions alongside the future development (Häder et al., 2020).
Other water quality studies at watershed scale explore the effects of historical land use changes on surface runoff and NPS pollution loading (Wu et al., 2012; Wang et al., 2016), but their integration into future perspectives are often ignored. Therefore, in some cases the effect of excess nutrients in a potential urban development remains unknown due to the inadequacy of information and restricted urban planning (Alberti et al., 2007), even though unique information and an outlook with regard to the water quality conditions can be derived (Lee et al., 2009). Nutrients in themselves are important for the function of aquatic ecosystems, but their availability in excess will result in distortion of the ecosystem (Baron et al., 2013).
In this study, a water quantity and quality model of a tropical river watershed is developed using the Hydrological Simulation Program Fortran (HSPF) model. HSPF has been used in modelling several watersheds considering various response parameters that includes; the hydrology (Biru and Kumar, 2018; Lee et al., 2020), sediments (Sarkar et al., 2019), and nutrients (Roostaee and Deng, 2019). Most of the studies have shown the robustness of the HSPF model in determining the effects of various best management practices at a watershed scale (Risal et al., 2021). Also, HSPF model have the ability to detect a small change in the land-use (as input data) and provides the likely responses of the watershed (Alukwe et al., 2014).
This study will provide information on the variation of TN and TP from NPS areas in a tropical watershed system under rapid urbanization settings that will act as a basis for management support and mitigation actions to curtail future water quality problems. Recently, Malaysia planned its future economic development corridors, out of which Johor Bahru, athe capital of Johor state (part of the Skudai River watershed) is one of them. The aim was to modernize the economic infrastructures and urban development areas that will attract investors. As a result, a rapid transformation is taking place in most part of the district. The Skudai River watershed represents the general characteristics of a tropical watershed considering its historical and planned urban development over the span of 5 decades. Part of Johor Bahru township falls within the watershed and its district is considered as one of the major urban area in Malaysia and most urbanized in Johor state (Rizzo, 2021). But the impacts of the rapid urban development and other anthropogenic activities that may lead to water quality deteriorations are not yet determined.
Section snippets
Nutrient transport process of HSPF model
HSPF version 12.4 (EPA, 2015) was used in this study. The model have a set of modules arranged in a hierarchical structure that performs a continuous simulation of a comprehensive range of hydrologic and water-quality processes (Shenk et al., 2012). It uses the concepts of a top-down structure and uniform data structures as well as programming conventions common in large-scale modelling efforts. In this study, the QUAL algorithm is applied to simulate three nutrient forms (orthophosphate,
Calibration and validation of HSPF model
The hydrological component of the Skudai River watershed was calibrated by adjustment of parameters using observed streamflow data from 2002 to 2007 and validated from 2008 to 2014 with monthly time steps (Fig. 4a,b). The model performance was good, with 11% overestimation of the flow, for the seven-year simulation period. The validation results show a satisfactory performance with captured variability of 83% and overestimation of 17% (Table 4). The NH3N, NO3N, and PO4-P concentrations were
Impact of land-use on the nutrient's pollutant
Prior studies have shown the impact of historical LU/LC on nutrient load from NPS areas (Garnier et al., 2013). However, this study presents the effects of LU/LC changes on the excess nutrient flow in a tropical watershed system using combined historical and future LU/LC. According to Wang et al. (2009), LU/LC change has been considered as a common occurrence that plays a significant role in regulating nutrient levels in the ecosystem. This study demonstrates how nutrient load from NPS areas
Conclusion
This study evaluates the effect of increasing urbanization on nitrogen and phosphorus pollution from NPS areas. It provides insightful information on how urban development changes the watershed response to nutrient flows under different LU/LC variations in a region of abundant rainfall. The HSPF model was used to evaluate these impacts in an urbanized watershed in Malaysia. As shown in the results obtained in this study, TN and TP load increases from 3.08 × 103 to 4.56 × 103 kg/yr and 0.13 × 103
CRediT authorship contribution statement
Al-Amin Danladi Bello: Conceptualization, Methodology, Software, Validation, Writing – original draft, Writing – review & editing. Mohd Ridza Mohd Haniffah: Data curation, Writing – original draft, Investigation, Supervision, Writing – review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This study was supported by the Department of Irrigation and Drainage Malaysia (DID), Department of Environment (DOE) and Indah Water Konsotium (IWK).
References (95)
- et al.
The impact of urban patterns on aquatic ecosystems: an empirical analysis in Puget lowland sub-basins
Landsc. Urban Plan.
(2007) - et al.
Interacting effects of climate change and agricultural BMPs on nutrient runoff entering Lake Erie
J. Great Lakes Res.
(2014) - et al.
Relationships between land use patterns and water quality in the Taizi River basin, China
Ecol. Indic.
(2014) - et al.
Evaluating nutrient impacts in urban watersheds: challenges and research opportunities
Environ. Pollut.
(2013) - et al.
Suggested classification of stream trophic state: distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus
Water Res.
(1998) - et al.
Towards efficient low impact development: a multi-scale simulation-optimization approach for nutrient removal at the urban watershed
J. Clean. Prod.
(2020) - et al.
A simple landscape design framework for biodiversity conservation
Landsc. Urban Plan.
(2015) - et al.
Modeling historical changes in nutrient delivery and water quality of the Zenne River (1790s–2010): the role of land use, waterscape and urban wastewater management
J. Mar. Syst.
(2013) - et al.
Analyzing the thermal comfort conditions of outdoor spaces in a university campus in Kuala Lumpur, Malaysia
Sci. Total Environ.
(2019) - et al.
Anthropogenic pollution of aquatic ecosystems: emerging problems with global implications
Sci. Total Environ.
(2020)
Diverse harmful microalgal community assemblages in the Johor Strait and the environmental effects on its community dynamics
Harmful Algae
Quantifying the cost-effectiveness of nutrient-removal strategies for a lowland rural watershed: insights from process-based modeling
Ecol. Model.
Nutrient conditions and the occurrence of a Karenia mikimotoi (Kareniaceae) bloom within East Johor Straits, Singapore
Regional Studies in Marine Science
Historical socio-environmental assessment of resource development footprints using remote sensing
Remote Sens. Appl. Soc. Environ.
Automatic calibration and improvements on an instream chlorophyll a simulation in the HSPF model
Ecol. Model.
Modeling approach to evaluation of environmental impacts on river water quality: a case study with Galing River, Kuantan, Pahang, Malaysia
Ecol. Model.
Landscape ecological approach to the relationships of land use patterns in watersheds to water quality characteristics
Landsc. Urban. Plan.
Urban ecological infrastructure: an integrated network for ecosystem services and sustainable urban systems
Journal of Cleaner Production
Recent trends in nutrient and sediment loading to coastal areas of the conterminous US: Insights and global context
Science of the Total Environment
Reducing surface water pollution through the assessment of the cost-effectiveness of BMPs at different spatial scales
J. Environ. Manag.
Influence of climate and land use changes on nutrient fluxes from Finnish rivers to the Baltic Sea
Agric. Ecosyst. Environ.
A modeling approach to evaluate the impacts of water quality management plans implemented in a watershed in Texas
Environ. Model. Softw.
Assessment of stormwater runoff management practices and governance under climate change and urbanization: an analysis of Bangkok, Hanoi and Tokyo
Environ. Sci. Policy
Mitigation options to reduce phosphorus losses from the agricultural sector and improve surface water quality: a review
Sci. Total Environ.
Impact of landscape pattern at multiple spatial scales on water quality: a case study in a typical urbanised watershed in China
Ecol. Ind.
Future climate and land uses effects on flow and nutrient loads of a Mediterranean catchment in South Australia
Sci. Total Environ.
Detecting the effect of land-use change on streamflow, sediment and nutrient losses by distributed hydrological simulation
J. Hydrol.
Spatial variability of soil total nitrogen and soil total phosphorus under different land uses in a small watershed on the Loess Plateau, China
Geoderma
Impacts of climate and land-use changes on the migration of non-point source nitrogen and phosphorus during rainfall-runoff in the Jialing River Watershed, China
J Hydrol
The influence of summer hypoxia on sedimentary phosphorus biogeochemistry in a coastal scallop farming area, North Yellow Sea
Science of The Total Environment
Sources and mechanisms of nitrate and orthophosphate transport in urban stormwater runoff from residential catchments
Water Res.
Projecting effects of land use change on human well-being through changes in ecosystem services
Ecol. Model.
Nonpoint pollution loading forecast and assessment of optimal area of constructed wetland in dam watershed considering climate change scenario uncertainty
Ecol. Eng.
Recovery of essential nutrients from municipal solid waste–Impact of waste management infrastructure and governance aspects
Waste Manag.
Sedimentation and water quality deterioration problems at Terengganu River Basin, Terengganu, Malaysia
Desalin. Water Treat.
Integrated hydro-economic modeling for sustainable water resources management in data-scarce areas: the case of Lake Karla watershed in Greece
Water Resour. Manag.
Effects of watershed land use data on HSPF water quality in the upper opequon watershed in Northern Virginia, USA
American Journal of Water Resources 2
Evaluation of gridded precipitation datasets in Malaysia
Remote Sensing
The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States
Biogeochemistry
Sand and gravel mining impact on the surface water quality: a case study from the city of Tirebolu (Giresun Province, NE Turkey)
Environ. Earth Sci.
Identification of critical source areas under present and projected land use for effective management of diffuse pollutants in an urbanized watershed
Int. J. River Basin Manag.
Will it rise or will it fall? Managing the complex effects of urbanization on base flow
Freshw. Sci.
Calibration and validation of SWAT model using stream flow and sediment load for Mojo watershed, Ethiopia
Sustain. Water Resour. Manag.
Adapting adaptive management for testing the effectiveness of stream restoration: an intensively monitored watershed example
Fisheries
Contribution of leaf litter to nutrient export during winter months in an Urban residential watershed
Environ. Sci. Technol.
Characterization and source identification of stormwater runoff in tropical urban catchments
Water Sci. Technol.
Cited by (5)
Effect of urbanization and urban forests on water quality improvement in the Yangtze River Delta: A case study in Hangzhou, China
2024, Journal of Environmental ManagementAdaptation measures under the impacts of climate and land-use/land-cover changes using HSPF model simulation: Application to Gongola river basin, Nigeria
2023, Science of the Total EnvironmentCitation Excerpt :For instance, Johnson et al. (2003) found an NSE of 0.67 for daily flow simulation for a 7-year period in Rochester watershed in New York. While, Bello and Haniffah (2021) reported NSE of 0.88 for calibrating monthly flow in Skudai watershed in Malaysia for a six-year period. The model validation results depict close agreements, between the measured and the simulated flows in both daily and monthly timescales, similar to the calibrated results (see Fig. 2c & d).
Simulation-based cost-risk analysis of phosphorus reduction alternatives: application to a mountainous watershed
2023, Modeling Earth Systems and Environment