Journal of Natural Resources and Environmental Management http://dx.
org/10.
29244/jpsl.
RESEARCH ARTICLE
Water Quality Degradation in the Deli River Watershed.
North Sumatra:
Impacts of Land Use and Pollution Sources Rusdi Leidonald.
Ahmad Muhtadi.
Muhammad Arif Ashshiddiq.
Vania S.
Siahaan.
Bunga Ulita Manurung Department of Aquatic Resources Management.
Faculty of Agriculture.
Universitas Sumatera Utara.
Medan, 20155.
Indonesia
Article History Received 14 August 2024
Revised 27 January 2025
Accepted 20 February 2025
ABSTRACT
Keywords aquatic pollutions.
North Sumatra, river, watershed, water quality The Deli Watershed is crucial in Medan's hydrological cycle and the surrounding areas.
It serves as a clean water source for Medan, but is also affected by urbanisation and industrial discharge.
This study aims to assess water quality using pollution indices and spatial analysis across the Deli Watershed.
Water samples were collected from the river in the watershed.
North Sumatra Province, between June and July 2023.
Observations were made at 46 spatial points through purposive These points represent the downstream .
ive point.
, middle .
, upstream .
, and tributaries .
The pollution status of the basin was determined using the Pollution Index, the National Sanitation Foundation-Water Quality Index (NSF-WQI), the Canadian Council of Ministers of the Environment (CCME), and the SingScore Method.
The spatial water pollution in the Deli Watershed varies from poor to good or excellent.
The most severe river conditions are observed in the downstream parts of the Sei Sekambing and Deli sub-watersheds, characterised by moderately to poorly polluted water.
Good or unpolluted river water quality was only found in 3 of 42 observation points, especially in the upper reaches of the Sembahe River and the Simai Mai River.
Therefore, serious steps are needed from the government to restore and rehabilitate the Deli River Basin area, namely forest areas, plantations, and tourist areas, especially in the upper reaches of the Deli River Basin, namely in the Karo and Deli Serdang Regencies.
Introduction Watersheds are interconnected ecosystems of rivers and tributaries that flow into the sea and are bounded by hills or mountains.
Rainwater in the watershed flows through rivers and eventually reaches the sea .
The river basins are divided into upstream .
ater-givin.
and downstream .
ater-receivin.
These factors influence each other in the watershed ecosystems .
Watersheds are integral to the processes of catchment, storage, and distribution of water resources.
They are vital for maintaining ecological biodiversity, serving as habitats for diverse aquatic organisms .
Ae.
Moreover, watersheds significantly contribute to the socioeconomic and cultural vitality of communities by supporting transportation, agriculture, and tourism, and offer potential for renewable energy generation through the development of micro and mini hydropower systems .
Ae.
The Deli Watershed covers Karo Regency.
Deli Serdang, and Medan.
It had an area of A353.
2 km 2.
Its upstream region is in the Deli Serdang Regency (Sibolangi.
and Karo, and it flows to Belawan (Meda.
The Deli Watershed plays a crucial role in the hydrological cycle of the Medan area and its surroundings.
The upstream part of the Deli Basin serves as a recharge area and source of clean water for Medan .
The Deli River divides Medan into eastern and western regions.
Historically, the Deli River served as a waterway during the era of the Deli Kingdom.
However, it currently encounters challenges due to uncontrolled urban development, which has caused the riverbanks to be compressed and damaged.
Land use in the upper part of the Deli Basin was dominated by farms/plantations .
%), agriculture .
7%), and settlements .
45%).
Only 11% of Sibolangit comprises forested areas .
Various land-use activities in the watershed area impact the condition of riverbanks and river ecosystems.
Uncontrolled land use activities can disrupt a basin's water Corresponding Author: Rusdi Leidonald Sumatera Utara.
Medan.
Indonesia.
leidonald@usu.
Department of Aquatic Resources Management.
Universitas A 2025 Leidonald et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC BY) license, allowing unrestricted use, distribution, and reproduction in any medium, provided proper credit is given to the original authors.
Think twice before printing this journal paper.
Save paper, trees, and Earth! system, thereby causing floods and erosion .
The expansion of plantations and tourism in the upland areas of Karo and Deli Serdang has made the land vulnerable to erosion and landslides.
The downstream part is vulnerable to floods due to land damage along the Deli Watershed .
ncluding the middle and downstream riverbank.
because of Medan's urban development, a metropolitan city .
,17Ae.
Various human uses and activities along rivers and water catchment areas affect the quality and quantity of river water .
Ae.
Changes in land use for agriculture, plantations, and settlements generally cause a decline in water quality and quantity .
The decline in water quality and quantity has a significant impact on productivity, carrying capacity, and the capacity of water sources.
A decline in river water quality has an impact on water pollution.
River pollution is caused by industrial, household/domestic, and agricultural activities that can pollute water sources with waste from these activities.
The increasing burden of pollutants entering the river is caused by the habits of people around the river who dispose of both liquid and solid domestic waste.
The amount of pollution is directly proportional to the increase in local population.
Ae.
River pollution reduces the availability of clean water and poses a risk of spreading various diseases.
Therefore, continuous research and monitoring of river water quality are necessary to ensure the availability of clean water and to prevent pollution.
The Deli Watershed in Medan City is one of the sources of clean water as an intake for the Medan City and Deli Serdang local water company (Perusahaan Daerah Air Minum/PDAM) .
Various studies have been conducted on the conditions of the Deli Watershed, including land conditions and water balance.
These studies include variations in land use around the Deli Watershed .
, evaluation of water availability .
, and studies of erosion and flooding .
Ae.
However, research on the water habitat conditions and water quality status in Deli Watershed has not yet been reported.
The latest report on water quality, especially microplastic pollution in the Deli River .
This study aims to assess water quality using pollution indices and spatial analysis across the Deli Watershed.
This research was also conducted to monitor the condition and quality of water in the Deli Watershed as an initial step in river and river basin management, particularly in the Deli Watershed.
Materials and Methods Study Area Water sampling was conducted from June to July 2023 in the Watershed.
North Sumatra Province.
Indonesia.
Observations were made at 46 spatial points using purposive sampling (Figure .
These points represent the downstream .
ive point.
, middle .
, upstream .
, and tributaries .
Water quality testing was conducted both directly at the research site .
n sit.
and at the Environmental Health and Disease Control Technical Institute (EHDCTI) Class I in Medan .
x sit.
Figure 1.
Map location research in the watershed.
This journal is A Leidonald et al.
JPSL, 15.
| 670
Measurement and Water Sampling The measured habitat and water quality parameters included 11 physical, six chemical, and two biological parameters (Table .
Certain parameters were measured directly in the field, whereas other parameters were analyzed in the laboratory.
The Medan Public Health Laboratory Center performed the laboratory Laboratory measurement and analysis methods refer to the American Public Health Association (APHA) .
Ae.
Table 1.
Instruments for Water Quality Parameter Measurement.
Parameters Temperature Brightness Turbidity Depth
Current velocity TDS
TSS
River width .
etted are.
River width
Riverbed substrate BOD
COD
Nitrate Phosphate Total coliform Macroinvertebrate Instrument/method DO meter/ Lutron DO-5510 Secchi disc Turbidity meter Scale board Flow meter TDS meter Spectrophotometer Roll meter Roll meter Visual pH meter (Atago DPH-.
DO meter/Lutron DO-5510 Incubation and Winkler titration Reflux method Spectrophotometer (UV-Vis Shimadzu 1.
Spectrophotometer (UV-Vis Shimadzu 1.
Most Probable Number (MPN) Family presence Unit
NTU
MPN/ 100 mL Description In-site In-site In-site In-site In-site In-site Ex site In-site In-site In-site In-site In-site Ex site Ex site Ex site Ex site Ex site Ex site Data Analysis Pollution Index (PI) Method The PI method has been developed for specific purposes.
It was then expanded for several purposes for an entire water body or a part of it.
This method was determined by selecting parameters that indicate good water quality if their values are low .
The pollution index calculations are expressed in Equation 1.
CIO 2
CIO 2
( ) maximum ( ) average LIO ycEya = Oo LIO Explanation:
PI : Pollution index, which is a function of Ci/Li Li : Standard value Ci : Measured concentration of water quality parameter .
The water quality is classified based on the PI Method as follows: 0Ae1 .
, 2Ae5 .
ightly pollute.
, 6Ae10 .
oderately pollute.
, and > 10 .
eavily pollute.
National Sanitation Foundation-Water Quality Index (NSF-WQI) Method NSF-WQI is an index of water quality developed in the United States by Ott .
It can be used in public water bodies, including lakes, rivers, and estuaries.
This index has been widely used in various countries.
determine water quality, the NSF-WQI method uses nine parameters: temperature, turbidity, pH.
BOD, nitrate, total phosphate, total solids, dissolved oxygen (DO), and fecal coliforms.
To calculate water quality, the sub-index (S.
value for each parameter was determined based on the measured parameter results in water samples extracted in the field (X.
using functional sub-index curves.
The NSF-WQI can be calculated using an online Water Quality Index Calculator website.
The sub-index values obtained for each parameter (S.
were multiplied by the weights for each parameter (W.
The formula used in the NSF-WQI method is as expressed in Equation .
The water quality is classified based on the NSF-WQI as follows: 0Ae25 (Very poo.
26Ae50 (Poo.
51Ae70 (Fair/moderat.
71Ae90 (Goo.
91Ae100 (Very goo.
http://dx.
org/10.
29244/jpsl.
JPSL, 15.
| 671
ycAycIya Oe ycOycEya = Ocycuycn=1 ycycn ycu ycIycn Explanation:
NSF-WQI : National Sanitation Foundation Water Quality Index Wi : Final weight of each parameter after adjustment Si : Sub-index of water quality for each parameter obtained from the analysis results and measurements compared with the sub-index curve n : Number of parameters Canadian Council of Ministers of the Environment (CCME) Method CCME was used to obtain water quality data through benchmark comparisons.
CCME has been used in Canada and other countries to determine sediment quality, drinking water quality, and agriculture.
It can be calculated using the formula .
expressed in Equation .
Water quality is classified as follows based on the CCME method: 95Ae100 .
, 80Ae94 .
, 65Ae79 .
, 45Ae64 .
, and 0Ae44 .
yayaycAya = 100 Oe Ooya12 ya22 ya32 Description:
: Number of parameters that do not satisfy the water quality standard : Number of test results that do not satisfy the water quality standard : Magnitude of the difference between the test results for a parameter and its standard value 732 : Normality value ranges from 0 to 100 SingScore Method The SingScore method is an improved version of the Biological Monitoring Working Party (BMWP) score .
and BMWPThai .
by Blakely et al.
This index was initiated by the Public Utilities Board (PUB) of Singapore .
he National Water Agenc.
based on the need for a macroinvertebrate biotic index specific to SingaporeAos flowing waters to monitor health and assess river ecosystems.
SingScore Likely Water Quality categories are as follows: 0Ae79 Poor.
80Ae99 Fair.
100Ae119 Good.
and > 120 Excellent .
The SingScore formula is as expressed in Equation .
ycIycnycuyciycIycaycuycyce = OcycIO=1 ycaIO where S is the total number of taxa in the sample, and ycaycn is the tolerance value for the ith taxon.
Results and Discussion Results Water Quality Characteristics Generally, the Deli Watershed is characterized by sandy-gravel substrates from downstream to upstream .
ub-watersheds of Patene.
Babura, and Bekal.
(Table 2Ae.
Only a few rocky substrates exist in the upper part of the Sembahe River in the Sibolangit.
This causes the Deli Watershed to appear turbid because the substrate is constantly stirred, which results in higher turbidity levels.
The turbidity in the Deli River ranges 6 to 78.
3 NTU.
Clear waters were observed only on rocky substrates in the middle of the Patene subwatershed and the upper reaches of the Sembahe River.
In addition to substrate factors, land cover conditions influence turbidity: clear water locations are observed in the upper reaches of the Sembahe and Simai Mai Rivers, which are still forested.
This is consistent with previous studies in the Batangtoru .
Alassingkil watersheds .
, and Wampu watershed .
This indicates that sandy substrates exhibit higher turbidity than rock-gravel substrates.
Similarly, areas with more open land cover, such as plantations or other agricultural activities, have higher turbidity than areas that are still covered by forests.
Turbidity in the Deli Watershed was also caused by extensive sand mining.
Dissolved oxygen concentrations in the Deli Watershed show different concentration differences between river segments.
In the upstream and middle parts, respectively, and the oxygen concentration was high.
The presence of river currents and the low organic material content caused this.
Currents in rivers are the main This journal is A Leidonald et al.
JPSL, 15.
| 672
source of oxygen in water.
The concentration of organic matter in the Deli Watershed was higher downstream than in the upstream and middle regions.
This can be observed from the high concentrations of BOD and COD downstream.
However, in the middle part, the BOD content is also quite high because it is a residential area in Medan city.
In several other cases in Indonesian rivers, the same trend is observed, with BOD and COD concentrations being higher downstream than upstream.
This is an accumulation of organic material that builds up from the upland part and is carried downstream .
Ae.
Phosphate measurements revealed relatively high values ranging from 0.
4 to 6.
0 mg/L downstream.
Even in the upstream areas, the phosphate values range from 0.
2 to 0.
6 mg/L.
The phosphate values range from 0.
0 mg/L in the upper reaches of Kwala Bekala.
This is reasonable given that the upstream areas of Patene in Brastagi are agricultural fields, whereas the upper reaches of Bekala and Babura have palm oil plantations.
Lower phosphate concentrations are observed in the upper reaches of the Sembahe River .
orest areas: 0.
1Ae 15 mg/L).
In this study, the total coliform levels in samples from the Deli Watershed ranged between 1,600 and 16,000 MPN/100 ml.
The highest coliform value was observed at points 1 and 2 .
,000 MPN/100 m.
, whereas the lowest was observed at point 15 .
,500 MPN/100 m.
Table 2.
Water conditions and quality in the Deli sub-watershed area.
Temperature TDS
TSS
Turbidity Current velocity Substrate AC AAS/cm NTU River width etted are.
River width
Brightness Depth
Surrounding BOD
COD
Nitrate Phosphate Total coliform Sub-watershed Deli Watershed Down Middle 7Ae31.
0Ae30.
56Ae86 15Ae102 84Ae160 33Ae175 7Ae26 7Ae10 4Ae78.
6Ae32 5Ae1.
5Ae1.
MuddySand-gravel 20Ae50 8Ae25 28Ae60 2Ae0.
2Ae1.
Settlement MPN/100 ml 0Ae8.
7Ae4.
3Ae18.
2Ae65 2Ae5.
4Ae1.
16,000
Parameter Unit 12Ae35 2Ae0.
2Ae1.
Settlementagriculture 6Ae8.
1Ae8.
4Ae8.
3Ae30.
4Ae5.
1Ae0.
1,700Ae16,000 Petane Middle 5Ae27.
77Ae165 145Ae335 7Ae9 73Ae3.
5Ae1.
Rock 10Ae13 Upstream Petane 3Ae32 54Ae779 92Ae1,020 8Ae20 56Ae516 3Ae1.
Gravelrock 5Ae2.
15Ae20 2Ae1.
2Ae1.
Farm/ 2Ae8.
0Ae9.
3Ae5.
6Ae46.
1Ae3.
1Ae0.
1,500Ae1,700 5Ae4 3Ae1.
2Ae1.
Farm/ 5Ae7.
1Ae8.
4Ae15 10Ae35 7Ae3.
2Ae0.
500Ae1,600 Simai Mai Upstream Middle Sembahe stream 6Ae22.
16Ae178 32Ae326 2Ae8 5Ae1.
3Ae1.
2Ae0.
Rock Sand Upstream 2Ae5 3Ae0.
Gravelrock 3Ae10 2Ae0.
2Ae0.
Forest Farm Forest 6Ae8 2Ae8.
5Ae4.
5Ae14.
5Ae2.
1Ae0.
0Ae1,700 1,500 Table 3.
Water conditions and quality in the Deli sub-watershed area.
AAS/cm NTU Sei Sekambing Middle stream 2Ae30.
149Ae175 225Ae266 18Ae25 3Ae78.
1Ae0.
Concrete 5Ae13 Babura Middle stream 9Ae31.
88Ae96 168Ae184 16Ae21 5Ae44.
2Ae0.
Sand-gravel 5Ae11 Bekala Upstream 0Ae29.
101Ae104 198Ae206 12Ae18.
3Ae93.
2Ae0.
Gravel-rock 5Ae13 Sei Sekambing Middle stream 3Ae31.
99Ae102 168Ae200 18Ae27 1Ae56.
1Ae0.
Sand-gravel 11Ae15 Babura Middle stream 0Ae26.
60Ae104 110Ae204 13Ae18 3Ae23.
2Ae0.
Gravel-rock 6Ae7 8Ae18 5Ae0.
1Ae0.
5Ae13 2Ae0.
2Ae0.
10Ae20 1Ae0.
1Ae0.
15Ae18 2Ae0.
2Ae0.
10Ae12 2Ae0.
2Ae0.
Parameter Unit
Temperature TDS
TSS
Turbidity Current velocity Substrate River width .
etted are.
River width Brightness Depth http://dx.
org/10.
29244/jpsl.
JPSL, 15.
| 673
Sei Sekambing Middle stream Settlement Babura Middle stream Settlement Bekala Upstream Farm MPN/100 ml 0Ae6.
4Ae3.
3Ae18.
45Ae75 4Ae0.
3Ae6.
15,000Ae16,100 9Ae7.
2Ae8.
5Ae19.
15Ae80 0Ae5.
21Ae0.
1,700
2Ae7.
8Ae8.
5Ae21.
18Ae80 5Ae4.
4Ae1.
1,700
Parameter Unit
Surrounding land
BOD
COD
Nitrate Phosphate Total coliform Sei Sekambing Middle stream Settlementagriculture 1Ae6.
5Ae4.
6Ae18.
40Ae65 3Ae3.
2Ae0.
1,700
Babura Middle stream Farm/plantation 2Ae6.
8Ae8.
0Ae22.
77Ae80 9Ae4.
4Ae2.
1,700
Water Quality Status It is evident from the calculation results of the various water quality indices and bioindicator methods that the spatial conditions of the water bodies in the Deli River Watershed vary from poor to good or very good (Table .
The worst river conditions were observed in the Sei Sekambing sub-watershed, with water status ranging from moderately polluted to poor.
Field observations also indicate that the condition of the Sei Sekambing sub-watershed can be considered poor.
It is characterized by an unpleasant smell and black water.
The polluted condition of the Sei Sekambing sub-watershed is reasonable because its headwaters do not reach the Karo Highlands/Sibolangit area, but only in the northern part of Medan City.
This causes the water flow to deviate from normal, similar to other sub-watersheds.
The Sei Sekambing sub-watershed appears to be a more precise drainage channel for urban waste in Medan.
In the downstream part of the Deli River Watershed, the water conditions displayed marginal pollution (CCME method/water quality standard class II) to poor conditions (NSF-WQI and Sing scor.
The PI method indicates marginal pollution .
ater quality standard class II).
The statuses differed owing to variations in several parameters calculated for the various In the downstream and middle parts of the Deli River, where turbidity levels were high.
NSF WQI measurements were significantly affected.
However, in the PI and CCME methods, turbidity is not included in the calculations because the turbidity parameters do not have standardized values according to regulations in Indonesia .
Based on the SingScore method, focusing on macroinvertebrates as bioindicators, only a group of molluscs that were highly tolerant to pollutants was observed.
This condition belongs to the poor category according to the SingScore method .
Table 4.
Pollution status of the Deli River Watershed.
North Sumatra Province.
Sub-watershed Segment
Deli Watershed Down stream
Middle stream
Sei Sekambing Middle stream
Babura
Middle stream
Upstream
Bekala
Middle stream
Upstream
Petane Upstream Sembahe Upstream Petane Simai Mai
Middle stream
Upstream
Calculation method
PI*
NSF-WQI
CCME*
SingScore Lightly polluted .
07Ae3.
Lightly polluted .
63Ae3.
Moderately polluted .
15Ae6.
Lightly polluted .
57Ae3.
Lightly polluted .
46Ae3.
Lightly polluted .
61Ae3.
Lightly polluted .
61Ae3.
Lightly polluted .
40Ae3.
Good .
58Ae0.
Lightly polluted .
32Ae2.
Good .
70Ae0.
Poor .
61Ae44.
Poor .
18Ae48.
Poor .
61Ae37.
Fair/moderate .
12Ae63.
Fair/moderate .
46Ae64.
Fair/moderate .
28Ae65.
Fair/moderate .
97Ae70.
Fair/moderate .
75Ae66.
Good .
61Ae82.
Fair/moderate .
47Ae67.
Good .
60Ae82.
Marginal .
Marginal .
Poor Fair Fair Fair Fair Fair Good Fair Good Poor .
Ae.
Fair .
67Ae.
Poor .
Ae.
Fair .
Ae.
Good .
Ae.
Fair .
67Ae.
Good .
Ae.
Good .
Ae.
Excellent .
Ae.
Fair .
Ae.
Excellent .
Ae.
*Quality standards refer to class II .
This journal is A Leidonald et al.
JPSL, 15.
| 674
In the middle part of the Deli River Watershed, water conditions range from lightly polluted to poor.
This poor condition is based on the NSF-WQI method.
Turbidity plays a role in determining whether the middle section belongs to the poor category.
However, when observed in the field, the middle section of the Deli River should likely be categorized as moderate.
This is because water flow and river discharge, which can help "cleanse" pollutants, still exist.
This provides habitat for aquatic organisms.
This is also evident from field observations, where native river fish are found in the middle part of the Deli River.
Mystacoleucus marginatus was abundant in this area.
Catfish (Mystu.
are still commonly observed and are popular among fishermen for fishing activities in the Deli River.
This was supported by observations performed using the SingScore This places the middle part of the Deli River in the fair category.
The water quality status also displays light pollution in other segments of the Deli River Watershed, namely the Babura.
Bekala, and Upstream Petane Sub-watersheds.
Pollutants in these river segments include organic matter, phosphate, and total This is reasonable because these river segments are located in agricultural, residential, and tourist River segments classified as good/very good in the Deli River Watershed were observed in the headwaters of the Sembahe and Simai Mai Rivers.
This is because of the natural conditions of the rivers in forested areas.
Discussion According to a report from the Watershed Management Agency II (RBMA) .
, the Deli Watershed is divided into five sub-watersheds: the Deli Sub-watershed.
Sei Sekambing.
Babura.
Bekala.
Patene, and Simai Mai (Table .
The Deli Sub-watershed includes an urban area and part of the northern region.
Residential and plantation areas characterize it.
It constitutes the downstream and middle streams of the watershed, with river conditions constrained by settlements.
The substrate characteristics were silt and sandy mud from an estuary downstream of Medan Labuhan.
In certain areas, riverbanks are constructed using retaining walls.
The habitat characteristics and water quality in the middle part of the Deli Sub-watershed are characterized by sandy and gravelly sandy substrates.
According to a recent report, land cover in the watershed is dominated by plantations .
%), agriculture .
7%), and settlements .
45%).
Only 11% is designated as forested area in the Sibolangit region .
This is the primary reason that the Deli watershed becomes turbid directly, particularly during the rainy season.
Agricultural activities contribute to nutrient pollution .
articularly phosphat.
in the Deli Watershed .
In general, it can be stated that the Deli River Watershed is polluted, except for the headwaters of the Sembahe and Simai Mai Rivers.
The pollution sources in the Deli River Watershed originate from community activities in the upstream and middle parts of the watershed, mainly agricultural, plantation, and tourism.
downstream areas, pollution results from the accumulation of upstream pollutants combined with urban community activities.
Domestic waste from urban areas, containing detergents, household waste, and industrial waste, increases the BOD and COD values and pathogenic bacteria .
hich are discharged directly into water bodie.
The abundance of coliform bacteria indicates a biological deterioration in the environmental conditions of the river because coliform bacteria serve as indicators of water pollution .
The presence of coliform bacteria in water indicates the presence of pathogenic microbes, which are hazardous to human health.
The high coliform bacterial content in the water samples can result in the presence of other pathogenic bacteria.
This is because coliforms are positively correlated with other pathogenic bacteria.
The higher the level of coliform bacterial contamination, the higher is the risk of the presence of other pathogens commonly observed in human and animal feces.
Escherichia coli is a pathogenic bacterium that may be present in contaminated water.
It is a microbe that causes symptoms such as diarrhea, fever, abdominal cramps, and vomiting .
Ae.
Several rivers and watersheds in Indonesia have varying levels of pollution.
The Belawan River in North Sumatra displays mild to moderate pollution .
The Ciliwung River in Jakarta and West Java exhibits moderate to severe pollution .
The Cisadane River in Banten is moderately polluted .
The Citarum River Watershed in West Java belongs to the category of moderate-severe pollution .
,21,.
In general, river pollution in Indonesia comprises organic pollution, with certain cases involving heavy metals .
,48Ae Meanwhile, using several methods to strengthen the results obtained, especially in the middle and upper reaches of the river, the difference was only noticeable downstream, where a slight difference was observed.
This also occurs because of the quality standards, where if Class I is used in the IP and CCME methods, the results are close to those of the NSF-WQI and Singscore.
This indicates that the Deli River is no longer classified as a Class I .
lean water sourc.
, except for the upper reaches of the Sembahe River.
http://dx.
org/10.
29244/jpsl.
JPSL, 15.
| 675
The quality status of the Deli Watershed and its polluted tributaries is a warning to the community and the This is based on the Deli Watershed water being used by the community in the upstream and middle areas as a source of clean water.
even the local water company (PDAM) utilizes it as one of the sources of clean water in Medan.
It is known that organics, including total coliforms, pollute the Deli River water and pose a health risk.
Water contaminated with coliforms can serve as a vector for human diseases.
Therefore, real action is needed from the government to restore and improve the Deli watershed ecosystem.
Conversion and land clearing in the upper part of this river basin are significant issues that contribute to habitat destruction and river pollution.
It is necessary to reorganize the upper lands that have been converted into plantations and tourist areas.
This land clearing causes erosion and increases the river turbidity, resulting in frequent flooding.
Controlling the use of river boundaries is also a step that needs to be taken by the government, considering that the banks of the Deli watershed, especially the Medan City area, are becoming Conclusions Spatially, the condition of the waters in the Deli River Basin can be said to be in a worrying condition.
The downstream part of the Deli River is in an unhealthy state.
The downstream part of the Deli River is included in the category of lightly polluted (PI method with a score of 3.
07Ae3.
74 and CCME with a score of 65, according to class II water quality standard.
to bad (NSF-WQI with a score of 36.
61Ae44.
21 and Singscore with a score of 20Ae.
The middle and upstream segments of the Deli River Basin also exhibit polluted water conditions, as indicated by the same four methods, which all show the same status.
Good water status was still found in the upstream areas of the Sembahe River (Petane Sub-DAS) (IP Score 0.
58Ae0.
NSF-WQI Score 81.
61Ae82.
CCME Score 75Ae90.
Singscore Score 126Ae.
and Simai Mai (IP Score 0.
7Ae0.
NSF-WQI Score 81.
60Ae82.
CCME Score 77Ae85.
Singscore Score 130Ae.
Author Contributions RL: Conceptualization.
Data Curation.
Funding Acquisition.
Methodology, and Writing - Original Draft.
AM:
Investigation.
Methodology.
Supervision, and Writing - Review & Editing.
MAS: Investigation and Methodology.
PSPS: Investigation and Methodology.
BUM: Investigation and Methodology.
Conflicts of Interest There are no conflicts to declare.
Acknowledgments We thank the University of North Sumatra for funding this research through the Talented Research Scheme, as per the USU Research Institute Decision Letter (No.
301/UN5.
1/PPM/2023, dated 25 August 2.
References