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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.

Show MeSH
Changes in annual surface runoff depth between 1990 and 2000; (-) indicates an increase in surface runoff values from 1990 and (+) a decrease in runoff depth values in 2000.
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pone.0125805.g005: Changes in annual surface runoff depth between 1990 and 2000; (-) indicates an increase in surface runoff values from 1990 and (+) a decrease in runoff depth values in 2000.

Mentions: The results of the spatial distributions of modelled annual runoff depth (in mm) in 1990 and 2000 are shown in Fig 5A and 5B, respectively. The surface runoff depth in 1990 was much higher than that in 2000, when it varied from 17 to 190 mm/year, particularly in the mountainous areas with forest cover and shrubland. The significant decline in surface runoff can be attributed to the conversion of forest and shrubland to irrigated cropland. Another reason is the construction of 25 rainwater harvesting and recharge dams in the area, which control surface runoff and allow farmers to extend their fields and increase their income at the expense of forest and shrubland.


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)

Changes in annual surface runoff depth between 1990 and 2000; (-) indicates an increase in surface runoff values from 1990 and (+) a decrease in runoff depth values in 2000.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0125805.g005: Changes in annual surface runoff depth between 1990 and 2000; (-) indicates an increase in surface runoff values from 1990 and (+) a decrease in runoff depth values in 2000.
Mentions: The results of the spatial distributions of modelled annual runoff depth (in mm) in 1990 and 2000 are shown in Fig 5A and 5B, respectively. The surface runoff depth in 1990 was much higher than that in 2000, when it varied from 17 to 190 mm/year, particularly in the mountainous areas with forest cover and shrubland. The significant decline in surface runoff can be attributed to the conversion of forest and shrubland to irrigated cropland. Another reason is the construction of 25 rainwater harvesting and recharge dams in the area, which control surface runoff and allow farmers to extend their fields and increase their income at the expense of forest and shrubland.

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