Abstract
Abstract. Assessment of changes of water bodies and vegetation by traditional methods is very difficult and costly. The use of satellite data makes it possible to study water bodies and vegetation more accurately and cost effectively. Accordingly, various digital methods have been developed to discover and detect changes of earth's surface features. Flood is one of the important factors contributing to the destruction of natural resources. The purpose of this research is to evaluate the flood areas in the Aghqala area in Golestan province of Iran. The level of water bodies in the spring of 2018 and 2019 was compared and evaluated based on the NDWI and MNDWI indices using Landsat images. The results showed that water bodies’ area in the spring of 2018 was 24.13 km2 which increased to 185.34 km2 at 2019 using NDWI; while the MNDWI due to the excessive sensitivity to the water considered agriculture wetlands as an area of water bodies. Therefore, the NDWI yielded more logical results. Also, change detection methods based on spectral and radiometric information using indices are more accurate than the classification maps and more changes can be shown. Using satellite imagery to monitor changes is essential to facilitate the planning of natural hazards management.
Highlights
Flooding is one of the most common and destructive natural hazards affecting human life and creating many economic problems around the world
Water Index (NDWI) using Near Infrared (NIR) and green wavelengths can highlight open water features, which modified by Xu (2006) by substituting the middle infrared band for NIR band and called it MNDWI
The normalised difference water index (NDWI) index is designed to maximize the reflection of water by using green wavelengths, minimizing the low reflectance of NIRs by water features, and the high reflectance of NIRs by vegetation and soil features (Xu, 2006)
Summary
Flooding is one of the most common and destructive natural hazards affecting human life and creating many economic problems around the world. Change detection is a process that allows observing and recognizing the time series differences of features, complications, and patterns of the earth's surface. Since various phenomena such as water and plant objects have different pigment levels and so different reflectance, using indices to distinguish different bodies is necessary. Kish (2002) used remote sensing technique to evaluate the surface area of Lake Jackson and Florida based on climatic elements The results of these time series studies showed that flood-water fluctuations can be monitored and evaluated accurately by remote sensing technology. As well as the change detection methods including image change workflow and classification methods were compared
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
