Groundwater provides freshwater supply for multiple purposes such as drinking water, irrigation, and industrial processes. Due to intensive developments, contaminants from various land use practices infiltrate into the groundwater system and jeopardized the existing quality. Besides, uncontrolled groundwater extraction exacerbate the existing issue due to improper management and uncontrolled extraction; especially in developing areas. This study centralized in Kuala Langat; an urbanized basin with mix of land use practices (residential, industrial, and agricultural) with the aim to observe the impacts of land use activities towards groundwater hydrochemistry on seasonal and temporal scale. A total of 30 groundwater samples were collected along Langat River Basin to assess the physicochemical parameters, concentration of major ions and heavy metals. Application of multivariate and graphical analysis as well as pollution indices were incorporated in this study to evaluate the degree of heavy metals contamination. The order of cations concentration evaluated in pre- and post-monsoon seasons are Na > Ca > K > Mg and Na > Mg > Ca > K, respectively while the order of anions concentration is HCO3>Cl > SO4 for both monsoon seasons. Both calculated HPI and Cd value suggested that agricultural activity is the main contributor for groundwater pollution. Overall, most of the stations are potable to be consumed as stated from HPI and Cd results except for station SSG10. It is suggested that for a better precaution, the groundwater in Langat River Basin shall undergo prior treatment before further consumption.

Pantai Punggur, Batu Pahat is a bustling town located on the Southwest Coast of Peninsular Malaysia, situated along the west coast of Malaysia. Despite its bustling nature, the area is prone to coastal flooding. In response, coastal defence structures have been constructed to protect the coastline. However, the issue lies that this structure cannot fully prevent coastline exposure to wave overtopping caused by strong waves or coastal inundation from high tidal fluctuations that exceed normal sea levels. Pantai Punggur has undergone the concerning issue, and it is worsening. Therefore, this study uses numerical modelling (MIKE21 Software) to investigate the wave scenario from the historical data of wind and tide in Pantai Punggur, Batu Pahat. The study location was digitised, and a new model MESH was developed in the MIKE21 Zero MESH Generator. The historical data from the ERA5-Reanalysis Dataset covering all 12 months (2022) at one-hour intervals was collected. To validate the new model MESH, the RMSE method was employed, which required achieving a result below the 10% threshold. Correlation analysis was conducted monthly throughout the year and revealed distinct relationships between significant wave height (SWH) and wind speed (indicating wave overtopping) and tidal levels (indicating coastal inundation). The correlation between tidal levels and SWH showed a stronger correlation than with wind speed, with the highest R-value reaching 0.5886 (34.64%). Hence, it can be seen that the stronger correlation between tidal level and SWH compared to wind speed and SWH, suggests that tidal fluctuations have a more substantial impact on wave heights and the potential fall on coastal inundation rather than wave overtopping resulting in coastal flooding. The current studies provide essential information relevant to conservation practices and future planning.

This one-day event offers a unique opportunity to discover how MIKE Powered by DHI software and other innovative DHI technologies are being used to tackle water challenges across Malaysia. Presentations will be delivered by DHI experts, along with insightful case studies shared by our clients. Through a series of technical sessions, interactive discussions, and networking opportunities, participants will gain practical insights into combining advanced modelling tools with local expertise to support a more water-resilient Malaysia. We welcome professionals from regulatory bodies, local authorities, environmental and civil engineering consultancies, industry, and academia to join us for a day of learning, collaboration, and professional growth.

1.0 KEMUDAHAN DI MAKMAL HIDRAULIK DAN INSTRUMENTASI 2.0 KERJASAMA PENYELIDIKAN & RAKAN STRATEGIK 3.0 TERMA SEWAAN FASILITI DAN KEMUDAHAN MHI 4.0 KADAR SEWAAN FASILITI DAN KEMUDAHAN MHI

Sebanyak tiga sampel air telah di ambil pada 22 April 2025(Selasa) pada jam 10.30 pagi dan di tandakan sebagai S1 (station 1) air dari dalam bangunan dipercayai air tanah (groundwater), S2 air dari pancuran di luar (surfacewater) dan S3 air dari kolam diluar bangunan (Surfacewater). Lokasi Persampelan di tandakan di dalam peta dan berdasarkan gambar (Gambar 1). Berikut merupakan analisis kimia yang telah di jalankan dan di analisis di Makmal Kualiti air NAHRIM (Jadual 1). Keputusan analisis air dalam unit mg/L.

This study examines the interaction of physical and biogeochemical factors in the development of hypoxia in Teluk Bahang, Penang Island, during July to August 2024. In situ observations analyzed the influence of neap and spring tides on hydrological and biochemical parameters such as temperature, salinity, dissolved oxygen (DO), turbidity, pH, and chlorophyll-a (Chl-a). Results indicate that neap tides cause significant water stratification with thermocline, halocline, and pycnocline gradients that facilitate phytoplankton production near the pycnocline. In contrast, spring tides enhance nutrient redistribution and surface Chl-a concentration. The tidal dynamics, monsoon changes, and anthropogenic nutrient inputs interact complexly to determine DO distribution, with spring tides promoting vertical mixing and oxygen exchange, while neap tides and monsoon transitions exacerbate hypoxia, especially in deeper waters. Unique features of Teluk Bahang, such as its enclosed bay structure, local nutrient loading, and seasonal monsoon influence, make it highly susceptible to hypoxia. These findings deepen understanding of spatial hypoxia variations in estuarine environments and provide a basis for future three-dimensional modeling and hypoxia forecasting.

Laporan ini menganalisis data satelit altimetri bagi Laut China Selatan dan perairan Malaysia untuk mengkaji anomali paras laut (SLA) dari tahun 1993 hingga 2020. Data yang diproses oleh DUACS dari AVISO+ menunjukkan peningkatan SLA sebanyak ~4 cm/dekad di kebanyakan perairan Malaysia, dengan kadar lebih tinggi (4.5-5 cm/dekad) di kawasan pantai barat Sarawak dan pantai timur Sabah. Kajian ini menggunakan produk altimetri beresolusi 0.25° × 0.25° dan menyediakan perisian MATLAB untuk mengestrak dan memvisualisasi tren paras laut di lokasi tertentu. Cabaran utama termasuk ketepatan pengukuran altimetri berhampiran pantai akibat gangguan isyarat radar oleh daratan.

Laporan ini menganalisis kualiti air marin di Selat Johor melalui pencerapan in-situ di 10 stesen sepanjang 13.3 km dari Woodlands ke Puteri Harbour pada September 2022. Lima parameter diukur (kemasinan, suhu, konduktiviti, TSS, pH) menggunakan AquaTROLL 600 semasa keadaan pasang surut neap dan spring. Analisis statistik seperti boxplot, linear regression, dan PCA menunjukkan WQ7 (kedalaman 27.8 m) mencatatkan nilai tertinggi bagi kebanyakan parameter, tetapi suhu dan pH lebih tinggi di WQ2 akibat arus perlahan. Konduktiviti dan kemasinan berkorelasi tinggi (0.61-1.00), manakala TSS dipengaruhi faktor cuaca dan arus. Kajian ini mengesyorkan penilaian semula hubungan parameter untuk memahami dinamik kualiti air marin

The Dungun River salinity intrusion model for well mixed alluvial estuaries is developed. The parameters are schematized with the amount of salinity data incorporated with estuary geometry and tide relationship

This study evaluates the implications of sea level rise on the coastal areas of Kelantan and Terengganu, focusing on coastline dynamics, estuary changes, and community adaptability. Utilizing Geographic Information System (GIS) data and sediment rating curves, the research analyzes sediment transport, erosion, and flow distribution across major rivers, including Sungai Kelantan and Sungai Terengganu. Key findings reveal that Ibai catchment exhibits the highest soil erosion (70.13 ton/ha/year) due to urbanization, while Kelantan shows the lowest (22.98 ton/ha/year) due to extensive forest cover. Flow duration curves indicate a linear relationship between rainfall and river flow, with larger catchments like Terengganu (4596 km²) showing tripled flow at ARI 50. The study underscores the need for enhanced coastal management strategies to mitigate erosion and flooding risks, particularly in vulnerable areas like Kijal, Terengganu.

Tangki NAHRIM, a desktop application developed in 2008, is widely used for the calculation of optimal tank size for rainwater harvesting in Malaysia. Here we present an overview of the updated version, Tangki NAHRIM 2.0 (TN2) which was developed in the R computing environment. In TN2, a rainwater harvesting system is simulated using a daily water balance model with rainfall input from a built-in database by adopting the yield-after-spillage (YAS) convention. Proposed tank sizes are evaluated based on water saving and storage efficiencies. These results are then visualised in charts showing the relationships between tank sizes and both efficiency measures to help users select the optimal tank size based on their criteria of choice. A simulation was conducted based on a typical Malaysian household for domestic non-potable use as a case study. A web-based GUI for TN2 was devel- oped in R Shiny framework for the public. The GUI has the advantage of being accessible online from any device, and will be able to facilitate the adoption of rainwater harvesting systems by the public at large.

The National Lake Water Quality Criteria and Standards (NLWQS) for Malaysian lake water use is essentially a user needs specification of the quality of water required for different protection uses. The criteria is intended to provide the required information in making judgments as to the fitness of lake water for human protection (i.e. recreational purposes) and aquatic life protection (i.e. ecosystem health). The NLWQS are applicable to any lake or reservoir, dams, ponds and other impoundments water of any usage or purposes. This standard is also to be used by the owner of the water body as a primary source of information and decision-support to judge the fitness of the said water body and for other water quality management purposes.

Pemahaman umum berkenaan greywater adalah air sisa yang terhasil daripada aktiviti cucian pakaian, pembasuhan pinggan mangkuk, dapur, mandian, dan cucian kereta. Walau bagaimanapun, definisi yang tepat dan urus tadbir dari segi aspek perundangan, kawalan pelepasan dan piawaian kualiti air berkaitan greywater di Malaysia adalah masih longgar dan perlu diperkasakan. Pemahaman umum bahawa greywater adalah sebahagian daripada air kumbahan juga adalah tidak tepat kerana greywater dan air kumbahan memiliki kualiti dan karakter yang amat berbeza. Sehubungan itu dalam usaha kerajaan menambahbaik pengurusan greywater di Malaysia, pihak NAHRIM telah dilantik oleh Jabatan Perkhidmatan Pembetungan (JPP) sebagai agensi pelaksana untuk menjalankan kajian analisis situasi semasa berkaitan tadbir-urus greywater di Malaysia. Kajian ini melihat kepada keperluan menentukan aktiviti-aktiviti yang menjadi punca utama penghasilan greywater, mengenalpasti parameter-parameter kualiti air yang boleh dijadikan indikator penentuan punca pencemaran greywater, menambahbaik garis panduan sedia ada terutama dari segi takrifan dan tafsiran greywater, kelompongan undang-undang sedia ada dan memperlihatkan teknologi rawatan pelepasan greywater hasil kajian kepakaran tempatan. Objektif yang disasarkan dalam kajian ini adalah untuk memperkasakan pengurusan dan pentadbiran greywater di Malaysia terutama aspek kualiti air dan pencemaran yang terangkum di bawah bidang kuasa kementerian. Oleh yang demikian, kajian perintis ini akan memberi fokus kepada pengenalpastian parameter-parameter yang boleh menjadi ukuran tahap pencemaran greywater, menentukan punca-punca pelepasan greywater dan aktiviti-aktiviti yang menyumbang kepada pelepasan greywater. Standard dan piawaian yang diamalkan oleh negara-negara maju seperti Australia dan Singapura dijadikan rujukan utama dalam kajian ini kerana Malaysia masih belum mempunyai standard khusus bagi mengawal-selia kualiti air pelepasan greywater ke dalam longkang dan sungai. Buku infografik ini juga turut mengetengahkan tadbir urus, penguatkuasaan serta kawalan yang dilaksanakan oleh pihak berkuasa tempatan mengikut daerah dan negeri iaitu di Bahagian Dua dan Bahagian Tiga buku ini. Salah satu komponen penting dalam buku ini juga adalah kupasan berkenaan inovasi dan teknologi rawatan greywater yang dibangunkan oleh jabatan, institusi dan universiti tempatan seperti yang dipaparkan di bahagian empat buku infografik ini. Inovasi dan teknologi yang telah dibangunkan dengan kepakaran tempatan diharap dapat menjadi rujukan untuk membantu jabatan yang berkaitan dan pihak berkuasa tempatan dalam usaha mengawal pencemaran greywater, memperkasa kaedah tadbir-urus sedia ada dan mengalakkan penggunaan semula greywater.

Malaysia has been facing water scarcity with insufficient water resources to meet the increasing water demand, especially in urbanised and developed areas. Water scarcity is mainly affected by climate condition which has controlled the availability of renewable freshwater resources and the seasonality of water supply. It is also affected by water demand which is based on population trends and socio-economic developments. The severe El Nino phenomenon occurred in 1997-1998 and 2015-2016 where precipitation decreased significantly and caused a prolonged drought. Water resources shortage due to the inability of the water supply dam to provide a sufficient amount of water has affected water supply disruption to the entire population especially in Selangor and Klang Valley. This research focused on the development of water stress index on water resources assessment under global climate change impacts in Klang Valley (Selangor, Wilayah Persekutuan Kuala Lumpur and Wilayah Persekutuan Putrajaya). Water stress is becoming more localised and should include relevant geographical and temporal dimensions in its representation. The water stress index (WSI) is used to obtain a comprehensive understanding of the current and future status of water resource conditions related to the sustainability of water resources. The research will carry out WSI analysis which indicates the ratio of water resources availability/water yield value to the water demand/water use which will gradually be increasing for 2015, 2020, 2030, 2040 and 2050 with selected 4 climate change scenarios with 15 realisations as reported in Special Report on Emission Scenarios by the Inter- Governmental Panel on Climate Change, Assessment Report No. 4 (SRES IPCC AR4). Development WSI for Klang Valley is assessed to identify the potential districts that will be facing water stress in existing and future conditions due to climate change impacts. Water Stress Index (WSI) shown that Klang Valley has been experiencing extremely high and high water stress under climate change scenario (SRES A1B). The analysis indicated that the water resources availability and water yield are gradually increasing at 7% while at the same time the water demand is rapidly increasing at 16% from 2030 to 2050. Assessment of water surplus and deficit was calculated to determine the ratio of water availability against water demand. The WSI maps produced will able to assist the required adaptation measures such as the identification of alternative water resources as the supplementary water supply is necessary to ensure water security in the future. Water stress projections in relation to climate change need to be developed as a predecessor to policies and infrastructural intervention for long-term water security and sustainability.

With the changing climate, the prognosis is that weather extremes such floods, drought and El Nino are likely to increase in frequency and intensity can expand billions of economic losses and effect human lives. NAHRIM Hydroclimate Data Analysis Accelerator (N-HyDAA), known as Malaysia Climate Change (CC) Knowledge Portal, the only CC knowledge portal in Malaysia is primarily developed for providing CC and water-related data, information, knowledge and technology which is crucial for present and future water related business activities, engineering practices and environment. It has eight hydroclimate-environment modules, which amongst others are rainfall, floods, droughts and water stress condition using Big Data Analytics (BDA) technology by means of comprehensive analysis and interactive visualization tools. N-HyDAA is able to trace, detect, identify and visualise future water issues associated with the adverse impacts of climate change in Malaysia. N-HyDAA assist business entities, water operators, engineers, planners and decision-makers in designing, planning and developing water related program and risk management in combating climate change impact either mitigation or adaptation actions.

PREFACE It gives It gives us a great pleasure to publish this framework document for managing our precious water resources and the water-related risks associated with climate change to leaders and policy-makers in Malaysia. This framework also aims to facilitate the formulation of sound policies and best practices that support sustainable water management and ensure water security, especially in dealing with climate change impacts. This interdisciplinary and multi-sectoral is the work of climate scientists, adaptation experts, government officials, private sectors, non-governmental organizations and civil society leaders in Malaysia. It was developed based on five pillars, which are: knowledge, management, implementation, gaps, and what’s next. We recommend this framework document to be a reference to our leaders and policymakers. By adopting the five pillars and building partnerships, which involved thegovernment and various stakeholders, we believe that this framework is comprehensive enough to support the country’s agenda towards enhancing the water security. Finally, special thanks go to the team for their hard work towards the successful publication of this book. Dato’ Seri Ir. Dr. Zaini bin Ujang Secretary General Ministry of Environment and Water Dato’ Ir. Dr. Hj. Md. Nasir bin Md. Noh Director General National Water Research Institute of Malaysia

Redang Island is one of the largest islands off the east coast of Malaysia and situated 45 km from Kuala Terengganu. It is one of nine islands, which form a marine park, and which offer snorkelling and diving opportunities. At present, Redang Island deemed one of the 10 most beautiful islands in the world. The Pulau Redang archipelago comprises Pulau Redang, Pulau Lima, Pulau Paku Besar, Pulau Paku Kecil, Pulau Kerengga Kecil, Pulau Kerengga Besar, Pulau Ekor Tebu, Pulau Ling and Pulau Pinang. Redang Island is the biggest of all the islands in the Marine Park, measuring about 7 km long and 6 km wide. Its highest peak is Bukit Besar at 359 metres above sea level. While, Pantai Pasir Panjang (Long Beach) is the most popular destination in the Redang Island as almost 90% of the tourists stay there. Therefore, the demand for clean water supply especially in the island is increasing from year to year due to rapid tourist arrival. In this context, evaluation of the water resources especially groundwater, in terms of availability, distribution and quality, is needed in order to meet this increasing demand for fresh water and also to formulate future planning and development of water resources. Thus, it is important to collect hydrogeological, geophysical and hydrochemical data to determine the available resources and assess the possible impact or consequence of indiscriminate exploitation of groundwater resources that might deteriorate the groundwater quality. It also could help to augment the restoration of fresh groundwater quantity.

Pusat Kajian Sumber Air dan Perubahan Iklim (PKSA) telah melaksanakan kajian mengenai potensi kegunaan air hujan untuk tujuan air minuman (pembotolan minuman air hujan) melalui pelaksanaan projek penyelidikan sistem inkubator yang dibina di bangunan Makmal Hidraulik & Instrumentasi (MHI). Objektif utama kajian adalah untuk mengumpul, merawat, dan membotolkan air hujan sebagai air minuman yang mematuhi spesifikasi piawai air minuman berbungkus. Produk akhir adalah pembotolan air hujan sebagai air minuman berbungkus yang menggunakan dua sumber tadahan air hujan. 1. Air Minuman Berbungkus Jenama CloudRain@NAHRIM (Air Hujan Terawat) Kajian mengenai potensi kegunaan air hujan untuk tujuan air minuman (pembotolan air hujan) melalui pelaksanaan projek penyelidikan Sistem Penuaian Air Hujan (SPAH) yang dibina di Surau Taqi Al-Din, NAHRIM dan Inkubator Air Minuman Berbungkus (AMB) – Pemprosesan air hujan terawat yang dibina di NAHRIM. 2. Air Minuman Berbungkus Jenama Raindrops (Air Hujan Terawat) Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM) telah melaksanakan kajian mengenai potensi kegunaan air hujan untuk tujuan air minuman (pembotolan air hujan) melalui pelaksanaan projek penyelidikan Sistem Penuaian Air Hujan (SPAH) yang dibina di Taman Negara Kuala Tahan, Pahang dan Inkubator Air Minuman Berbungkus (AMB) – Pemprosesan air hujan terawat yang dibina di NAHRIM.

Water Resources and Climate Change Research Centre (PKSA) has published NAHRIM Technical Guide No. 2: Design Guide for Rainwater Harvesting System (RWHS). The development of this technical guideline is to provide a reference for developers, researchers, local governments and individuals who involved in the design and installation of Rainwater Harvesting System. The objectives are: To provide an easy-to-follow guide to the public/users in designing and installing a RWHS for residential use; To give same ideas to the public how a typical RWHS functions through the illustrations of the various components of the system; It is a design guide for the typical residential systems and easy to understand/follow by the public/users;

This study evaluates the implications of sea level rise on the coastal areas of Kelantan and Terengganu, focusing on coastline dynamics, estuary changes, and community adaptability. Utilizing Geographic Information System (GIS) data and sediment rating curves, the research analyzes sediment transport, erosion, and flow distribution across major rivers, including Sungai Kelantan and Sungai Terengganu. Key findings reveal that Ibai catchment exhibits the highest soil erosion (70.13 ton/ha/year) due to urbanization, while Kelantan shows the lowest (22.98 ton/ha/year) due to extensive forest cover. Flow duration curves indicate a linear relationship between rainfall and river flow, with larger catchments like Terengganu (4596 km²) showing tripled flow at ARI 50. The study underscores the need for enhanced coastal management strategies to mitigate erosion and flooding risks, particularly in vulnerable areas like Kijal, Terengganu.