Predicting the flood inundation area based on the results of previous analysis using GIS and spatial analysis techniques

Oct 13, 2025 by wbrum.org 31 views

Analysis of Potential Flood Risks on DAS which includes Medan by using a Geographic Information System (GIS)

Introduction

The city of Medan, located in the province of North Sumatra, Indonesia, is prone to flooding due to its geographical location. The Belawan Sungai and Deli River Basin (DAS) plays a crucial role in influencing land conditions and the city environment. The increase in flood discharge from the two rivers has caused an increasingly widespread flood plain, increasing the risk of floods that have the potential to cause losses and damage due to standing water. This study aims to analyze quantitatively and systematically the potential risk of flooding in the Belawan and Deli watershed by utilizing the Geographic Information System (GIS).

Background

The Belawan Sungai and Deli River Basin (DAS) is an integral part of the city of Medan, with these two watersheds playing a crucial role in influencing land conditions and the city environment. The increase in flood discharge from the two rivers has caused an increasingly widespread flood plain, increasing the risk of floods that have the potential to cause losses and damage due to standing water. This study aims to analyze quantitatively and systematically the potential risk of flooding in the Belawan and Deli watershed by utilizing the Geographic Information System (GIS).

Objectives

In this analysis, there are three main objectives:

Analyze the potential for flooding using Hec-Ras software: This objective aims to analyze the potential for flooding in the Belawan and Deli watershed using Hec-Ras software.
Predicting the flood inundation area based on the results of previous analysis using GIS and spatial analysis techniques: This objective aims to predict the flood inundation area based on the results of previous analysis using GIS and spatial analysis techniques.
Estimating the risks caused by floods: This objective aims to estimate the risks caused by floods in the Belawan and Deli watershed.

Methodology

Map data needed in the preparation of this information includes rainfall maps, topographic maps, Medan City infrastructure maps, and land use maps. These maps are very important for calculating flood discharge with a return period of 25, 50, and 100 years. Eligible and transverse measurements from the river are also carried out to get the river water level through Hec-Ras. The results of the Hec-Ras analysis were then overlayed with the Medan City infrastructure map. By utilizing GIS, the estimated flood risk can be done more accurately.

Results

The results showed that the Deli River had a significant flood potential with a puddle height of 5 meters and the inundation area reached 11.74 km², resulting in the formation of 30 inundation areas in the city of Medan. Losses experienced by residents affected by floods reached 219,658 people, with a total loss cost of around Rp 846,750,183,208.

Meanwhile, the Babura River created a flood puddle as high as 4 meters and the area of inundation was 3.20 km², with 14 inundation areas formed. A total of 60,711 people affected by the estimated loss of Rp 270,150,698,007. On the other hand, the Belawan River raises the height of the flood inundation also reaching 4 meters, but with an area of inundation of only 0.30 km² and forming 3 inundation areas. Losses experienced by residents in this region reached 12,625 people with a total cost of around Rp 41,940,528,190.

Infrastructure affected by floods due to the overflow of the Deli and Babura River includes 13 secondary arterial roads, 6 units of transportation infrastructure, 5 main facilities, and 401 public facilities units. Meanwhile, floods from the Belawan River have an impact on 1 secondary arterial road, 2 units of transportation infrastructure, and 6 units of public facilities.

Discussion

Through this study, it can be concluded that flood risk analysis using GIS is very important to understand the impact caused by flooding on the community and infrastructure in the city of Medan. This is a significant first step in planning a more effective and efficient flood risk mitigation. Identification and mapping of flood-prone areas can help decision makers in designing disaster risk reduction policies, as well as increasing awareness and preparedness of the community facing flood disasters in the future.

Conclusion

In conclusion, this study has demonstrated the importance of flood risk analysis using GIS in understanding the impact caused by flooding on the community and infrastructure in the city of Medan. The results of this study have shown that the Deli River has a significant flood potential, while the Babura and Belawan Rivers also have a potential for flooding. The study has also highlighted the importance of infrastructure planning and design in reducing the risk of flooding in the city of Medan.

Recommendations

Based on the results of this study, the following recommendations are made:

Conduct regular flood risk analysis: Regular flood risk analysis should be conducted to identify areas prone to flooding and to develop strategies for reducing the risk of flooding.
Develop flood risk reduction policies: Flood risk reduction policies should be developed to reduce the risk of flooding in the city of Medan.
Increase awareness and preparedness: Awareness and preparedness of the community facing flood disasters should be increased through education and training programs.
Improve infrastructure design: Infrastructure design should be improved to reduce the risk of flooding in the city of Medan.

Limitations

This study has several limitations, including:

Limited data availability: The study was limited by the availability of data, particularly rainfall and topographic data.
Simplification of flood modeling: The study used a simplified flood modeling approach, which may not accurately represent the complexity of flood behavior.
Limited spatial resolution: The study was limited by the spatial resolution of the GIS data used.

Future Research Directions

Future research directions include:

Development of more accurate flood modeling approaches: More accurate flood modeling approaches should be developed to improve the accuracy of flood risk analysis.
Integration of social and economic factors: Social and economic factors should be integrated into flood risk analysis to better understand the impact of flooding on the community and infrastructure.
Development of flood risk reduction strategies: Flood risk reduction strategies should be developed to reduce the risk of flooding in the city of Medan.
Frequently Asked Questions (FAQs) about Flood Risk Analysis using Geographic Information System (GIS)

Introduction

Flood risk analysis using Geographic Information System (GIS) is a crucial tool for understanding the impact of flooding on communities and infrastructure. However, there are many questions that people may have about this topic. In this article, we will answer some of the frequently asked questions (FAQs) about flood risk analysis using GIS.

Q: What is flood risk analysis using GIS?

A: Flood risk analysis using GIS is a method of analyzing the potential for flooding in a given area using geographic information system (GIS) technology. GIS is a computer-based tool that allows users to collect, store, analyze, and display geographically referenced data.

Q: Why is flood risk analysis using GIS important?

A: Flood risk analysis using GIS is important because it helps to identify areas that are prone to flooding and to develop strategies for reducing the risk of flooding. This can help to save lives, reduce property damage, and minimize economic losses.

Q: What are the benefits of using GIS for flood risk analysis?

A: The benefits of using GIS for flood risk analysis include:

Improved accuracy: GIS can provide more accurate results than traditional methods of flood risk analysis.
Increased efficiency: GIS can automate many of the tasks involved in flood risk analysis, making it faster and more efficient.
Better decision-making: GIS can provide decision-makers with the information they need to make informed decisions about flood risk reduction strategies.

Q: What are the limitations of using GIS for flood risk analysis?

A: The limitations of using GIS for flood risk analysis include:

Data availability: GIS requires accurate and up-to-date data, which may not always be available.
Complexity: GIS can be complex to use, especially for those without experience with the technology.
Cost: GIS software and hardware can be expensive.

Q: What are some common applications of GIS in flood risk analysis?

A: Some common applications of GIS in flood risk analysis include:

Flood mapping: GIS can be used to create detailed maps of flood-prone areas.
Flood modeling: GIS can be used to simulate the behavior of floodwaters and predict the impact of flooding.
Flood risk assessment: GIS can be used to assess the risk of flooding in a given area.

Q: How can GIS be used to reduce the risk of flooding?

A: GIS can be used to reduce the risk of flooding in several ways, including:

Identifying flood-prone areas: GIS can be used to identify areas that are prone to flooding.
Developing flood risk reduction strategies: GIS can be used to develop strategies for reducing the risk of flooding.
Monitoring flood risk: GIS can be used to monitor flood risk and provide early warnings of potential flooding.

Q: What are some best practices for using GIS in flood risk analysis?

A: Some best practices for using GIS in flood risk analysis include:

Using accurate and up-to-date data: GIS requires accurate and up-to-date data to produce reliable results.
Using a variety of data sources: GIS can be used to combine data from a variety of sources, including remote sensing, field observations, and existing databases.
Using a range of analytical techniques: GIS can be used to apply a range of analytical techniques, including spatial analysis, statistical analysis, and modeling.

Q: What are some common challenges associated with using GIS in flood risk analysis?

A: Some common challenges associated with using GIS in flood risk analysis include:

Data availability and quality: GIS requires accurate and up-to-date data, which may not always be available.
Complexity: GIS can be complex to use, especially for those without experience with the technology.
Cost: GIS software and hardware can be expensive.

Q: What are some future directions for GIS in flood risk analysis?

A: Some future directions for GIS in flood risk analysis include:

Integration with other technologies: GIS can be integrated with other technologies, such as remote sensing and social media, to provide more comprehensive and accurate results.
Development of new analytical techniques: New analytical techniques, such as machine learning and artificial intelligence, can be developed to improve the accuracy and efficiency of GIS-based flood risk analysis.
Increased use of GIS in decision-making: GIS can be used to provide decision-makers with the information they need to make informed decisions about flood risk reduction strategies.