Satellite Detected Surface Waters & Evolution in Long An Province, Vietnam

This map illustrates the satellite-detected surface waters extent in the southern provinces of kien Giang, An Giang, Dong Thap & Can tho as observed from the Sentinel-1 SAR images acquired on 16 & 28 August 2018. In the analysed area, an increase of surface waters is observed mainly in agricultural and paddy fields areas. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas because of the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.

This map illustrates the satellite-detected surface waters extent in Ho Chi Minh City area and surroundings, as observed from the Radarsat-2 SAR image acquired on 18 December 2017. In the analysed area (~3000 km2) about 5,400 ha of lands, mainly agricultural and paddy fields are likely flooded. In addition, using WorldPop data, we can estimate that ~220,000 people are living within flooded areas. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas because of the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.

This map illustrates the satellite-detected surface waters extent in southern part of Vietnam, as observed from the Sentinel-1 images acquired on 07 November 2017, following the landfall of tropical cyclone DAMREY-17 ON 05 November 2017. In the analyzed area, 700,000 ha of lands, mainly agricultural and paddy fields are likely flooded. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.

**UNOSAT code: TC20201013VNM** This map illustrates satellite-detected surface waters in Ha Tinh and Nghe An Provinces of Viet Nam as observed from a Sentinel-1 image acquired on 18 October 2020. Within the analyzed area of about 9,000 km2, a total of about 500km2 of lands appear to be flooded. In Ha Tinh province, the water extent appears to have increased of about 300 km2 since 15 October 2020. Based on Worldpop population data and the detected surface waters, about 220,000 people are potentially exposed or living close to flooded areas. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT. Important Note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to backscattering properties of the radar signal.

This map illustrates the satellite-detected surface waters extent and evolution in north of Quang Binh Province, Vietnam, as observed from the Sentinel-1 images acquired on 12 and 24 October 2016. Within the analysed area, an increase of surface waters extent was observed from the 24 October 2016 image: ~4,400 ha of surface water were observed the 12 October 2016 and reached ~6,400 ha the 24 October 2016. All over the analysed zone, it corresponds to an evolution of about 45%. As example, in Tien Lang lake and dam an increase of water surface of 77 ha was observed corresponding to an evolution of ~70% by comparison to the water surface detected on 12 October 2016. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.

This map illustrates the satellite-detected surface waters extent and evolution in Binh Dinh Province, Vietnam, as observed from the Sentinel-1 images acquired on 07 November 2016 and 01 December 2016. Within the analysed zone, an increase of surface waters extent was observed between the 07 November 2016 and 01 December 2016. ~26,000 ha of surface water were observed the 07 November 2016 and reached ~49,400 ha the 01 December 2016. All over the analysed area, it corresponds to an evolution of about 90 % : An Nhon District (+5,950 ha), Tuy Phuoc District (+3,900 ha), Phu Cat District (+3,500 ha), Tay Son District (+3,200 ha), Phu My District (+3,000 ha) and Hoai An District (+2,000 ha). This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.