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Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

Mahmoud SH, Alazba AA - PLoS ONE (2015)

Bottom Line: Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region.The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams.The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000.

View Article: PubMed Central - PubMed

Affiliation: Alamoudi Water Research Chair, King Saud University, PO Box: 2460, 11451, Riyadh, Saudi Arabia.

ABSTRACT
The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

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pone.0125805.g001: Location map of study area.

Mentions: The Al-Baha region (Fig 1) is situated in Hejaz in the western part of the Kingdom of Saudi Arabia (41° 42′ E, 19° 20′ N). The smallest of the Kingdom’s provinces at 12,000 km2, Al-Baha was selected for this study because of the considerable divergence in its topography and climate. Al-Baha Province comprises six main districts, four of which are located in the Al-Sarah sector adjacent to ‘downtown’ Al-Baha, i.e. Al-Aqiq, Al-Mandaq, Al-Qura and Baljurashi, and two of which are in the Tihama sector, i.e. Al-Mekhwa (which includes Dhee Ain Village, or the Marble Village) and Qelwa. The climate of Al-Baha Province is greatly influenced by its varying topography. It is generally moderate in summer and cold in winter, with average temperatures ranging from 12–23°C. In Tihama, the climate is hot in summer, warm in spring and mild in winter, with humidity levels ranging between 52% and 67% and annual rainfall of less than 100 mm [30]. Although it is just 30 km from Tihama, the climate of the mountainous Al-Sarah area differs considerably. It is cooler in both summer and winter due to its high altitude. Al-Sarah is also subject to the formation of clouds and fog, which often occurs in winter because of the air masses coming in from the Red Sea and are accompanied by thunderstorms. In spring and summer, the climate is mild and pleasant. Al-Sarah also has higher annual rainfall than Tihama, in the range of 229–581 mm. Province-wide, average annual rainfall ranges from 100–250 mm [38].


Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

Mahmoud SH, Alazba AA - PLoS ONE (2015)

Location map of study area.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414520&req=5

pone.0125805.g001: Location map of study area.
Mentions: The Al-Baha region (Fig 1) is situated in Hejaz in the western part of the Kingdom of Saudi Arabia (41° 42′ E, 19° 20′ N). The smallest of the Kingdom’s provinces at 12,000 km2, Al-Baha was selected for this study because of the considerable divergence in its topography and climate. Al-Baha Province comprises six main districts, four of which are located in the Al-Sarah sector adjacent to ‘downtown’ Al-Baha, i.e. Al-Aqiq, Al-Mandaq, Al-Qura and Baljurashi, and two of which are in the Tihama sector, i.e. Al-Mekhwa (which includes Dhee Ain Village, or the Marble Village) and Qelwa. The climate of Al-Baha Province is greatly influenced by its varying topography. It is generally moderate in summer and cold in winter, with average temperatures ranging from 12–23°C. In Tihama, the climate is hot in summer, warm in spring and mild in winter, with humidity levels ranging between 52% and 67% and annual rainfall of less than 100 mm [30]. Although it is just 30 km from Tihama, the climate of the mountainous Al-Sarah area differs considerably. It is cooler in both summer and winter due to its high altitude. Al-Sarah is also subject to the formation of clouds and fog, which often occurs in winter because of the air masses coming in from the Red Sea and are accompanied by thunderstorms. In spring and summer, the climate is mild and pleasant. Al-Sarah also has higher annual rainfall than Tihama, in the range of 229–581 mm. Province-wide, average annual rainfall ranges from 100–250 mm [38].

Bottom Line: Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region.The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams.The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000.

View Article: PubMed Central - PubMed

Affiliation: Alamoudi Water Research Chair, King Saud University, PO Box: 2460, 11451, Riyadh, Saudi Arabia.

ABSTRACT
The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

Show MeSH