Makmal Hidraulik dan Instrumentasi (MHI) bertanggungjawab menjalankan aktiviti kajian dan pengujian melalui pemodelan fizikal bagi menyelesaikan isu-isu kejuruteraan hidraulik air berkaitan sungai dan empangan serta pantai dan samudera selaras dengan visi menjadi sebuah pusat rujukan penyelidikan pemodelan fizikal yang profesional dan komited bagi menyumbang kepada pembangunan yang mampan demi kesejahteraan dan peningkatan kualiti hidup rakyat. Salah satu kaedah untuk mencapai hasrat ini adalah dengan melaksanakan Sistem Pengurusan Kualiti berlandaskan kepada keperluan Standard ISO 9001:2015.

Objektif kualiti bagi sebuah makmal permodelan fizikal adalah untuk menjamin integriti, kebolehpercayaan, dan kesahan keputusan ujian yang dijalankan. Secara lebih terperinci, objektif kualiti membantu makmal dalam perkara-perkara seperti keterjaminan dan kualiti data, keselamatan operasi, menyokong akreditasi pensijilan iso 9001:2015, mengekalkan konsistensi dan replikasi yang baik dalam permodelan fizikal termasuk memupuk budaya kerja yang baik secara konsisten.

Kesedaran keselamatan dan pematuhan terhadap standard ISO 9001:2015 bukan sahaja melindungi kakitangan dan peralatan, tetapi juga menjamin kualiti, kebolehpercayaan, dan akreditasi keputusan ujian. Semua kakitangan makmal permodelan fizikal, hidraulik, dan instrumentasi disarankan untuk mengikuti SOP, menghadiri latihan keselamatan secara berkala, dan mengamalkan budaya kualiti dalam setiap aktiviti ujian. Dengan pengekalan standard dan akreditasi, makmal bukan sahaja mampu menghasilkan data yang boleh dipercayai tetapi juga meningkatkan reputasi dan keyakinan industri terhadap produk dan penyelidikan yang dijalankan.

Gridded precipitation products (GPPs) serve as an important alternative data source in Earth sciences where observational data is limited, particularly in tropical regions. Understanding their reliability is essential for continuous improvement and for guiding researchers in their selection. This study aims to evaluate the performance of APHRODITE, NASA POWER, and ERA5 in estimating precipitation over the Padas River Basin (PRB), a region frequently affected by floods. The assessment covers both overall precipitation variability and extremes, employing continuous and categorical statistical metrics as well as a probability distribution function (PDF). The results show that the GPPs reasonably capture the temporal variability of monthly and annual precipitation from 1990 to 2014, with moderate to high correlation coefficients (CC). However, APHRODITE consistently underestimated precipitation, while NASA POWER tended to overestimate it. Moderate-intensity precipitation (5–20 mm/day) was generally overestimated by the GPPs, resulting in a high detection of precipitation days, but this also caused approximately 40% of non-precipitation days to be misclassified as precipitation days. Moreover, the GPPs were less reliable in capturing precipitation extremes, as reflected in flood-related indices such as maximum one-day precipitation (Rx1day) and the frequency of heavy (R20mm) and extreme (R50mm) precipitation events, with low CC values and underestimated magnitudes. These findings suggest that the evaluated GPPs are appropriate for representing general precipitation patterns but less reliable for calculating precipitation extreme indices. Improvements in retrieval algorithms, observational calibration, and tropical process parameterization are recommended to enhance product reliability in the future.

Makmal Hidraulik dan Instrumentasi (MHI), Institut Penyelidikan Air Kebangsaan Malaysia (NAHRIM), telah mula beroperasi sejak tahun 2007 dengan keluasan MHI secara keseluruhan sekitar 12,000 m². MHI berperanan sebagai pusat penyelidikan dan pembangunan (R&D), perundingan, latihan, serta pengujian pemodelan fizikal hidraulik air dan kalibrasi peralatan makmal yang berkaitan. Antara fasiliti utama yang disediakan ialah Basin 30m, Basin 50m, Flume 50m dan Flume 100m, yang masing-masing dilengkapi dengan penjana ombak pelbagai arah dan magnitud serta penjana arus. Kaedah pemodelan fizikal di MHI diaplikasi untuk mengkaji interaksi ombak dan arus terhadap pelbagai jenis struktur hidraulik seperti pemecah ombak, struktur perlindungan pantai, pelabuhan serta produk hidraulik seperti pam air dan sistem mitigasi banjir. Melalui simulasi berskala, MHI turut menilai kesan pembangunan pantai serta impak tsunami terhadap struktur hidraulik bagi memastikan keberkesanan dan kecekapan reka bentuk strutur hidraulik. Antara pencapaian utama MHI termasuk pengiktirafan oleh Malaysia Book of Records bagi “Sistem Penuaian Air Hujan Terbesar untuk Makmal” (2018) dan “Model Skala Hidraulik Terbesar” (2020).

Makmal Hidraulik dan Instrumentasi (MHI), Institut Penyelidikan Air Kebangsaan Malaysia (NAHRIM), telah mula beroperasi sejak tahun 2007 dengan keluasan MHI secara keseluruhan sekitar 12,000 m². MHI berperanan sebagai pusat penyelidikan dan pembangunan (R&D), perundingan, latihan, serta pengujian pemodelan fizikal hidraulik air dan kalibrasi peralatan makmal yang berkaitan. Antara fasiliti utama yang disediakan ialah Basin 30m, Basin 50m, Flume 50m dan Flume 100m, yang masing-masing dilengkapi dengan penjana ombak pelbagai arah dan magnitud serta penjana arus. Kaedah pemodelan fizikal di MHI diaplikasi untuk mengkaji interaksi ombak dan arus terhadap pelbagai jenis struktur hidraulik seperti pemecah ombak, struktur perlindungan pantai, pelabuhan serta produk hidraulik seperti pam air dan sistem mitigasi banjir. Melalui simulasi berskala, MHI turut menilai kesan pembangunan pantai serta impak tsunami terhadap struktur hidraulik bagi memastikan keberkesanan dan kecekapan reka bentuk strutur hidraulik. Antara pencapaian utama MHI termasuk pengiktirafan oleh Malaysia Book of Records bagi “Sistem Penuaian Air Hujan Terbesar untuk Makmal” (2018) dan “Model Skala Hidraulik Terbesar” (2020).

KUALA LUMPUR - Fasa Peralihan Monsun dijangka bermula pada 30 Sept dan akan berlanjutan hingga November depan, sekali gus menandakan berakhirnya Monsun Barat Daya yang telah bermula sejak 10 Mei lepas. Jabatan Meteorologi Malaysia (METMalaysia) dalam kenyataan pada Jumaat memaklumkan semasa fasa peralihan itu, negara akan mengalami tiupan angin lemah dari pelbagai arah. "Keadaan ini berpotensi menggalakkan pembentukan awan ribut petir. Fenomena ini lazimnya membawa hujan lebat berserta angin kencang dalam tempoh yang singkat, terutamanya pada waktu petang dan awal malam,” menurut kenyataan itu. METMalaysia memaklumkan kawasan dijangka paling terkesan ialah Barat dan pedalaman Semenanjung Malaysia, Barat Sabah dan Sarawak. Fenomena cuaca berkenan berisiko menyebabkan banjir kilat, pokok tumbang, kepala air dan kerosakan pada struktur yang tidak kukuh. "Sehubungan dengan itu, orang ramai dinasihatkan untuk sentiasa berwaspada dan mengambil langkah berjaga-jaga selain sentiasa mengikuti maklumat terkini mengenai ramalan dan amaran cuaca melalui pelbagai saluran rasmi METMalaysia, termasuk laman web, aplikasi mudah alih myCuaca dan media sosial,” menurut kenyataan itu.

The regional ocean-atmosphere model components of GRIMS consists of Atmosphere – NCEP’s Regional Spectral Model (RSM) with spectral nudging turned on. It integrates also Ocean – Regional Ocean Modeling System (ROMS) and nutshell of the coding is refer toThe source code is a mixture F90 and F77 and run in Message Passing Interface (MPI) configuration (platform was used).

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 report provides updated future projections of sea level rise (SLR) along Malaysian coastlines, which are based on the updated processes generated by the global climate models or Earth system models from the 6th Phase of CMIP (i.e CMIP6) and also new methodologies recognised by the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report (AR6) era. Sea level has fluctuated across the South China Sea (SCS), with rates ranging from 3 to 5 centimeters every decade. In general, open ocean areas have lower sea level trends of roughly 2-3 cm/decade, whereas near-coast locations show greater trends of 3-5 cm/decade. Specifically, the eastern and northern coasts of Sabah have seen faster rates of sea level rise than the Strait of Malacca. The sea level along Malaysia's beaches has risen in recent decades. This is based on evidenced from both the tide gauge records as well as satellite altimetry. A robust linear regression analysis was conducted to compare the rate of change between local tide gauges and satellite altimetry data from 1993 to 2018. The estimated sea level trends from tide gauge average at 3.8 mm/year (excluding Miri and Sejingkat), while satellite altimetry yields an average of 4.4 mm/year. The SLR trends are generally higher in satellite altimetry except for Pulau Langkawi, Johor Bahru, and Kukup. The coastal areas of Sabah and the north-eastern coast of Peninsular Malaysia exhibit faster sea level rise compared to other regions. Both tide gauges and satellite altimetry indicate slightly larger sea level rise over the Malaysian coast compared to the global mean sea level rise since 1993. Kukup records the highest sea level change rate (5.9 mm/year) among tide gauge stations, while Bintulu in Sarawak shows the lowest trend (2.4 mm/year). Lahad Datu has the highest changing rate (5.6 mm/year) based on satellite altimetry, and Pulau Langkawi exhibits the lowest rate. The satellite altimetry data generally show slightly higher surface height anomalies compared to tide gauge records. The differences between satellite altimetry and tide gauge measurements may be attributed to localized coastal processes. Tool has been developed to extract the projection of SLR around SCS and adjacent regions. The future projections of sea levels based on the latest IPCC AR6 scenarios (ie. Shared Socioeconomic Pathways, SSPs) for the selected tide gauge locations, up to time horizon of 2100 are reported. The projections reflect the medium confidence processes as in IPCC AR6 and consider the contributions from thermal expansion, Greenland and Antarctic ice-sheets dynamic, glacier melting, changes in land water storage and also take into account regional changes from regional ocean dynamic based on the CMIP6 climate models, glacier isostatics adjustment and gravitational, rotational and deformation effect. Table S1 shows the projected changes of future sea levels at Malaysian coastline. The future changes in sea levels along the Malaysian coastlines vary across different SSPs by the end of the 21st century. The projected sea level rise ranges from approximately 0.4 m for SSP1-1.9 to around 0.9 m for SSP5-8.5, toward the end of 21st century. Despite marginal spatial variations, the SLR is slightly faster along the Sabah coastline but lower along the west coast of Peninsular Malaysia. Similar spatial variations in projected changes are observed for lower emission scenarios. Although the specific stations with maximum or minimum changes may differ, the sea level along the Sabah coastline is projected to rise more compared to other coastal areas. The projected median changes of sea level provided in this report is generally higher compared to the one reported in Impact of Climate Change: Sea Level Rise Projection for Malaysia 2017, NAHRIM (2019) by about 10 to 14 cm. In addition, the upper bounds of current projections are remarkably higher compared to the previously estimated in NAHRIM (2019). Local adaptation strategies need to consider these changes in the projection uncertainties. SLR is inevitable and is already starting to have an impact along the coastline of Malaysia. Coastal flooding, bund breaches and coastal erosion that occur along the coast could be attributed to SLR. Thus, this report has provided strategies and adaptation references for four (4) types of land use: Agriculture, Port & Harbour, Recreational & Tourism and Urban Areas. Planners, developers, managers and individual investors involved in land use development are recommended to consider this strategy coupled with the magnitude of SLR from this report (Figure 3.8 to Figure 3.28) in order to minimize the adverse effects of SLR on their project components.

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.

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.

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.

The occurrence of natural hazard is increasing in frequency and brings with it various impacts on coastal areas, such as coastal erosion along the shoreline of Malaysia. The study of National Coastal Erosion Study (NCES) in 2015 revealed that 8840 km of shoreline in Malaysia with 1,347.6 km were subjected to erosion. The present study selected seven locations in Kuala Terengganu since Terengganu is exposed to the northeast monsoon which could potentially cause coastal erosion. In order to identify the changes in the shoreline of the selected study areas, 2014 SPOT-5 and 2016 WorldView-3 images were processed using ArcGIS software to determine the shoreline changes and to categorise the erosion which has occurred. Results show that the erosion in Zone B is more dynamic compared to that in Zone A, as shown by the highest rate 8.04% of erosion from Pantai Rhu extending to Pantai Marang. Erosion in Pantai Batu Buruk and Kuala Ibai, respectively with Zone A dominated by the anthropogenic and natural factors, while Zone B dominantly by natural factor only. Therefore, finding an empirical study of analyses the shoreline erosion in Malaysian monsoon environment might provide valuable information for the shoreline erosion in Malaysian monsoon environment might provide valuable information for sustainability coastal management.

Pusat Kajian Sumber Air dan Perubahan Iklim (PKSA) telah melaksanakan kajian mengenai potensi kegunaan air hujan untuk tujuan air minuman melalui pelaksanaan projek penyelidikan Sistem Penuaian Air Hujan (SPAH) di Taman Negara, Kuala Tahan, Pahang dan Inkubator Pemprosesan Air Hujan (I -SPAH) bagi tujuan memproses Air Minuman Berbungkus (AMB) yang dibina di bangunan Makmal Hidraulik & Instrumentasi (MHI) Institut Penyelidikan Hidraulik Kebangsaan (NAHRIM). SPAH sumber Tadahan Kuala Tahan berlokasi di Taman Negara Malaysia yang terletak di Kuala Tahan, Pahang.

The growing attention to microplastics stems from their significant environmental and human impacts. Microplastic accumulation in the environment also contributes to the spread of micropollutants. Daily human activities involving the use of plastics, especially synthetic materials, lead to their eventual presence in wastewater treatment plants (WWTPs). Although WWTPs play a crucial role in removing microplastics during the treatment process, the technologies currently in use are not entirely effective in filtering out all microplastic particles. As a result, WWTPs are recognized as major contributors to microplastic release into the environment. This review delves into the sources and prevalence of microplastics, the methods used for their removal in WWTPs, and the potential risks they pose to human health. Several removal methods are discussed, including sedimentation and flotation, activated sludge and sedimentation, reverse osmosis, and rapid sand filtration. The efficiency of each method is critically assessed, highlighting their strengths and weaknesses in addressing microplastic contamination. Moreover, this review underscores the importance of ongoing comprehensive research and development to improve the removal efficiency of microplastics in WWTPs. Efforts to optimize existing removal techniques and investigate new technologies should be intensified to achieve more holistic microplastic removal. By tackling the microplastics issue at the WWTP level, we can reduce their release into the environment, thereby diminishing potential health risks. In conclusion, the environmental presence of microplastics and their associated micropollutants demands robust removal strategies within WWTPs.

Anthropogenic activities such as deforestation, urbanization, plantation agriculture, logging, and sand mining are well-established drivers of river system degradation and ecological imbalance within river basins. These activities have disrupted natural river flows and significantly altered land cover, adversely impacting both environmental conditions and local ecosystems. This study examines the impacts of land use changes and climate change on river equilibrium morphology in the Sungai Padas basin. The research involved developing digital maps to model storm events for 48- hour critical storm durations across 2-, 5-, 10-, 20-, 50-, 100-, and 1000-year Average Recurrence Intervals (ARI), considering both current and future land use changes (Scenarios 1a and 1b). Additionally, scenarios incorporating a Climate Change Factor (CCF) were assessed for the 2-, 5-, 10-, 20-, 50-, and 100-year ARIs for the Sungai Padas basin (Scenarios 2 and 3). The HEC-HMS model was employed to generate runoff hydrographs that reflect the effects of land use and climate change, while HECRAS was used to develop a hydraulic model simulating open channel and overbank flows under unsteady conditions, resulting in flood inundation maps. Sediment sampling conducted in September and December 2020 from five sites along Sungai Padas identified average bed material sizes (d50) ranging from 0.20 to 0.31 mm, classifying the river as a medium sand-bed system. Sediment rating curves were developed for three locations along Sungai Padas, based on total sediment load and discharge (Q) measurements. Furthermore, a hydrodynamic sediment transport model using Yang’s unit stream power function (1973) was developed to simulate channel-bed profile changes and identify areas of sedimentation and erosion along Sungai Padas and Sungai Pegalan. The simulation indicated a maximum sediment deposition of 5.59 m and erosion of 5.00 m following storm events. In total, 26 digital maps were produced, highlighting changes in bed elevation and potential locations for bank erosion. The simulation results for all scenarios (1a, 1b, 2, and 3) consistently identified bank erosion at the same locations. Based on these findings, a strategic approach to erosion and sediment control in response to land use changes and climate change impacts has been proposed. The management and development plans include eight action plans aimed at minimizing the effects of erosion and sedimentation to achieve sediment equilibrium for the Sungai Padas basin.

The Intergovernmental Panel on Climate Change (IPCC) adopted Representative Concentration Pathways (RCPs) for its comprehensive spectrum of future greenhouse gas emission scenarios for its Fifth Assessment Report (AR5) in 2014. NAHRIM has continued to update its Regional Hydroclimate Model (RegHCM) and investigate the impact of climate change on the hydro-climate of the country based on IPCC AR5 over the geographical region of Peninsular Malaysia, Sabah and Sarawak, with the latest publication of “The Impact of Climate Change on the Hydro-Climate of Malaysia Based on IPCC Fifth Assessment Report in 2021. Subsequent to this publication, NAHRIM has taken the initiative to update Technical Guide No. 1 (Estimation of Future Design Rainstorm under the Climate Change Scenario in Peninsular Malaysia) which was last completed in 2013 based on IPCC Fourth Assessment Report. Among the improvements included in this updated Technical Guide No. 1 are on the following various specifics: IPCC’s Fifth Assessment Report (from AR4 to AR5), types of Global Climate Models (GCMs), scenarios (from stabilisation to RCPs scenarios), finer spatial resolution (from spatial grid 9-km to 6-km resolution), and time resolution (from daily to hourly for Peninsular Malaysia). A total of 154 rainfall stations (managed by DID) in Peninsular Malaysia were selected to be analysed for the calculation of climate change factor (CCF) associated with return periods of 2, 5, 10, 20, 25, 50, and 100 years. Sub-daily climate change factor is produced by which the daily precipitation data from RCP scenarios were downscaled using Equidistance Quantile Matching (EQM) method. In addition to the 154 at-site CCF values, CCF values for ungauged locations have been derived for regions (Eastern, Southern, West Central and Northern), as well as 10 km and 20 km spatial resolution gridded CCF maps. The average at-site CCF values for 154 rainfall stations in Peninsular Malaysia are estimated to be 1.12, 1.15, 1.17, 1.18, 1.18, 1.19 and 1.20 for return periods of 2, 5, 10, 20, 25, 50, and 100 years, respectively. It indicates an increment of 12% to 20% of rainfall intensity for return periods of 2 to 100 years, which leads to an increment of estimated design flood peak that needs to be considered in hydraulic structure sizing. This technical guide is useful to assist engineers, hydrologists and decision makers in designing, planning and developing water-related infrastructure in response to shifting climatic conditions. It will serve to introduce an approach of quantifying the scale of climatic change to surface water systems, particularly due to variability and alterations in precipitation pattern, through the development of at-site and regional climate change factor and formulation of the developed Intensity-Duration-Frequency relationship by Department of Irrigation and Drainage (DID) for future conditions.