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Water quality variation during a strong El Niño event in 2016: a case study in Kampar River, Malaysia

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El Niño and Southern Oscillation (ENSO) is a natural forcing that affects global climate patterns, thereon influencing freshwater quality and security. In the advent of a strong El Niño warming event in 2016 which induced an extreme dry weather in Malaysia, water quality variation was investigated in Kampar River which supplies potable water to a population of 92,850. Sampling points were stratified into four ecohydrological units and 144 water samples were examined from October 2015 to March 2017. The Malaysian Water Quality Index (WQI) and some supplementary parameters were analysed in the context of reduced precipitation. Data shows that prolonged dry weather, episodic and sporadic pollution incidents have caused some anomalies in dissolved oxygen (DO), total suspended solids (TSS), turbidity and ammoniacal nitrogen (AN) values recorded and the possible factors are discussed. The month of March and August 2016 recorded the lowest precipitation, but the overall resultant WQI remained acceptable. Since the occurrence of a strong El Niño event is infrequent and far between in decadal time scale, this paper gives some rare insights that may be central to monitoring and managing freshwater resource that has a crucial impact to the mass population in the region of Southeast Asia.
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Water quality variation during a strong El Niño event in 2016:
a case study in Kampar River, Malaysia
Casey Keat-Chuan Ng &Choo-Hou Goh &Jia-Chun Lin &Minn-Syenn Tan &
Willie Bong &Chea-Soon Yong &Jun-Yao Chong &Peter Aun-Chuan Ooi &
Wey-Lim Wong &Gideon Khoo
Received: 20 January 2018 /Accepted: 5 June 2018 / Published online: 15 June 2018
#Springer International Publishing AG, part of Springer Nature 2018
Abstract El Niño and Southern Oscillation (ENSO) is
a natural forcing that affects global climate patterns,
thereon influencing freshwater quality and security. In
the advent of a strong El Niño warming event in 2016
which induced an extreme dry weather in Malaysia,
water quality variation was investigated in Kampar Riv-
er which supplies potable water to a population of
92,850. Sampling points were stratified into four
ecohydrological units and 144 water samples were ex-
amined from October 2015 to March 2017. The Malay-
sian Water Quality Index (WQI) and some supplemen-
tary parameters were analysed in the context of reduced
precipitation. Data shows that prolonged dry weather,
episodic and sporadic pollution incidents have caused
some anomalies in dissolved oxygen (DO), total
suspended solids (TSS), turbidity and ammoniacal ni-
trogen (AN) values recorded and the possible factors are
discussed. The month of March and August 2016 re-
corded the lowest precipitation, but the overall resultant
WQI remained acceptable. Since the occurrence of a
strong El Niño event is infrequent and far between in
decadal time scale, this paper gives some rare insights
that may be central to monitoring and managing fresh-
water resource that has a crucial impact to the mass
population in the region of Southeast Asia.
Keywords Drought .El Niño .Pollution .Water quality
It is well established that El Niño and La Niña are
opposite extremes in a cycle that is scientifically known
as El Niño and Southern Oscillation (ENSO). It is a
natural alternating cycle of oceanic temperatures that
affects the global atmosphere, where an El Niño event
typically induces a warm climate pattern while a La
Niña event triggers a cool climate pattern (WMO
2014;Wangetal.2017). To monitor and predict an El
Niño event, the Oceanic Niño Index (ONI) is one of the
key measurables adopted globally. The index is derived
from sea surface temperature in the central Pacific
Ocean known as Niño 3.4, a region which spans from
longitude 120° to 170° W. The temperature difference
when averaged over a 3-month period is deduced as the
ONI and a strong positive ONI value characterises an El
Niño event (NOAA 2017). As with any country that is
located near the western Pacific, Malaysia is not exclud-
ed from the El Niño natural forcing.
Peninsular Malaysia typically receives 324 billion cu-
bic metres of rainwater annually and the current water
demand is only 11 billion cubic metres (EPU 2000). With
just roughly 3.4% of total precipitation used to satisfy
demand, freshwater shortage is not a common concern in
Malaysia. However, the problem lies in the fact that
precipitation is not uniformly distributed in yearly, decad-
al and century time scales. This is compounded by an-
thropogenic disturbances such as increasing forest
Environ Monit Assess (2018) 190: 402
C. K.<C. Ng (*):C.<H. Goh :J.<C. Lin :M.<S. Tan :
W. Bong :C.<S. Yong :J.<Y. Chong :P. A . <C. Ooi :
W.<L. Wong :G. Khoo
Faculty of Science, Universiti Tunku Abdul Rahman, Jalan
Universiti Bandar Barat, 31900 Kampar, Malaysia
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Variation in climate may also have an indirect influence on surface water health through changes in land scape pattern [7][8][9][10]. Accordingly, a deterioration of water quality has been observed in a number of studies on the influence of water quality due to climate change, particularly on water pollutants and their physio-chemical characteristics-such as DO, total suspended solid (TSS), ammonia (NH 3 ), and turbidity-within the changing hydrometeorological ecosystems [11][12][13]. Surface water quality has a diverse pattern of variations and it is not only a function of climate but also urbanization through anthropogenic activities [13][14][15]. ...
... Accordingly, a deterioration of water quality has been observed in a number of studies on the influence of water quality due to climate change, particularly on water pollutants and their physio-chemical characteristics-such as DO, total suspended solid (TSS), ammonia (NH 3 ), and turbidity-within the changing hydrometeorological ecosystems [11][12][13]. Surface water quality has a diverse pattern of variations and it is not only a function of climate but also urbanization through anthropogenic activities [13][14][15]. ...
... Similarly, DO rate is declining in all climatic classes except cold climatic region. From this finding, it can be agreed that water quality is a function of both water natural climate as well as anthropogenic activities [13][14][15]. Figure 10 shows the spatial scale interrelationship among the quantity of the river flow profile and the concentrations of BOD and DO. Usually, a high fresh-water flow rate is considered to improve the concentration of DO. ...
... On a watershed or basin scale, semi-empirical or deterministic models commonly are used for water quality modelings, such as the soil and water assessment tool (SWAT) , hydrologic simulation program Fortran (HSPF) (Kim, 2018b), water quality analysis simulation program (WASP) (Yang et al., 2012b), and integrated catchment model (INCA) (Whitehead et al., 2015(Whitehead et al., , 2018(Whitehead et al., , 2019b. More specifically, drought and water quality modeling approaches have been presented in studies through empirical regression models (HaRa et al., 2020;Ng et al., 2018), probabilistic numerical methods (Kim et al., 2019a) including copula joint probability distribution (JPD) , and an environmental fluid dynamics code (EFDC) model (Yang et al., 2015;Zhang et al., 2016). Water quality dynamics during flood events have been studied using numerical models such as MIKE (Si et al., 2022a;Li et al., 2017Li et al., , 2018aFeng et al., 2016), CE-QUAL-W2 (Chung and Oh, 2006;Chuo et al., 2019), a dynamics reservoir simulation model (DYRESM) (Wang et al., 2012, environmental fluid dynamics code (EFDC) (Zhang et al., 2013), Eco-Lake (Peng et al., 2021), WASP (Yang et al., 2012a), coupled SWAT, hydrological engineering centers river analysis system (HEC-RAS) (Ma et al., 2020), and HSPF (Quan and Meon, 2015). ...
... Accurate long-term streamflow and flood forecasting have always been a major research focus in hydro-climate studies. Natural climate variability (i.e., El Niño, La Niña) significantly impacts the intensity and evolution of droughts and floods (Forootan et al., 2019;Ng et al., 2018;Wei et al., 2020). The use of climate change scenarios could provide plausible long-term changes in precipitation, temperature, and many other climate parameters to help understand future changes in water quality. ...
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... From Figure 12c Figure 12). The primary cause of these interannual variations in precipitation extremes could be due to the strong ENSO effect during 2015-2016 (Burton et al., 2018;Ng et al., 2018;Tan et al., 2021). The influence of ENSO on the climate system in Peninsular Malaysia will be further discussed in section 3.3. ...
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... This has translated into recurring water shortage events in various parts of the country (Khor and Lee 1993;Abdullah 2002;Zainal Abidin 2004;Chan 2009;Malek et al. 2013;Ewing and Domondon 2016.). Moreover, Malaysia and many countries located in the western Pacific are also susceptible to the El Niño and Southern Oscillation (ENSO) forcing which typically reduces the annual frequency of precipitation (Juneng and Tangang 2008;Ng et al. 2018). Under such constraints, one would expect that the watersheds would be sensibly conserved and managed. ...
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Globally, freshwater shortage is one of the most dangerous risks for society. Changing hydro-climatic and socioeconomic conditions have aggravated water scarcity over the past decades. A wide range of studies show that water scarcity will intensify in the future, as a result of both increased consumptive water use and, in some regions, climate change. Although it is well-known that El Niño–Southern Oscillation (ENSO) affects patterns of precipitation and drought at global and regional scales, little attention has yet been paid to the impacts of climate variability on water scarcity conditions, despite its importance for adaptation planning. Therefore, we present the first global-scale sensitivity assessment of water scarcity to ENSO, the most dominant signal of climate variability. We show that over the time period 1961–2010, both water availability and water scarcity conditions are significantly correlated with ENSO-driven climate variability over a large proportion of the global land area (> 28.1 %); an area inhabited by more than 31.4 % of the global population. We also found, however, that climate variability alone is often not enough to trigger the actual incidence of water scarcity events. The sensitivity of a region to water scarcity events, expressed in terms of land area or population exposed, is determined by both hydro-climatic and socioeconomic conditions. Currently, the population actually impacted by water scarcity events consists of 39.6 % (CTA: consumption-to-availability ratio) and 41.1 % (WCI: water crowding index) of the global population, whilst only 11.4 % (CTA) and 15.9 % (WCI) of the global population is at the same time living in areas sensitive to ENSO-driven climate variability. These results are contrasted, however, by differences in growth rates found under changing socioeconomic conditions, which are relatively high in regions exposed to water scarcity events. Given the correlations found between ENSO and water availability and scarcity conditions, and the relative developments of water scarcity impacts under changing socioeconomic conditions, we suggest that there is potential for ENSO-based adaptation and risk reduction that could be facilitated by more research on this emerging topic.
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The ENSO observing system in the tropical Pacific plays an important role in monitoring ENSO and helping improve the understanding and prediction of ENSO. Occurrence of ENSO has been explained as either a self-sustained and naturally oscillatory mode of the coupled ocean-atmosphere system or a stable mode triggered by stochastic forcing. In either case, ENSO involves the positive ocean-atmosphere feedback hypothesized by Bjerknes. After an El Niño reaches its mature phase, negative feedbacks are required to terminate growth of the mature El Niño anomalies in the central and eastern Pacific. Four negative feedbacks have been proposed: reflected Kelvin waves at the ocean western boundary, a discharge process due to Sverdrup transport, western Pacific wind-forced Kelvin waves, and anomalous zonal advections. These negative feedbacks may work together for terminating El Niño, with their relative importance varying with time. Because of different locations of maximum SST anomalies and associated atmospheric heating, El Niño events are classified as eastern and central Pacific warming events. The identification of two distinct types of El Niño offers a new way to examine global impacts of El Niño and to consider how El Niño may respond and feedback to a changing climate. In addition to interannual variations associated with ENSO, the tropical Pacific SSTs also fluctuate on longer timescales. The patterns of Pacific Decadal Variability (PDV) are very similar to those of ENSO. When SST anomalies are positive in the tropical eastern Pacific, they are negative to the west and over the central North and South Pacific, and positive over the tropical Indian Ocean and northeastern portions of the high-latitude Pacific Ocean. Many mechanisms have been proposed for explaining PDV. Changes in ENSO under global warming are uncertain. Increasing greenhouse gases change the mean states in the tropical Pacific, which in turn induce ENSO changes. Due to the fact that the change in mean tropical condition under global warming is quite uncertain, even during the past few decades, it is difficult to say whether ENSO will intensify or weaken, but it is very likely that ENSO will not disappear in the future.