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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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Factors considered in the determination of surface runoff depth: (A) land cover 1990, (B) land cover 2000, (C) rainfall surplus, (D) slope and (E) soil texture.
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pone.0125805.g003: Factors considered in the determination of surface runoff depth: (A) land cover 1990, (B) land cover 2000, (C) rainfall surplus, (D) slope and (E) soil texture.

Mentions: Land cover data are required to achieve baseline climate data, and can also be used to assess the effects of land cover changes and other climate variables in an area’s hydrological response. In the study reported herein, the factors considered in determining the surface runoff depth (see Fig 3) were (1) the land cover map in 1990, (2) land cover map in 2000, (3) rainfall surplus (long-term annual average), (4) slope degree map and (5) soil texture. These factors were also used to develop an ArcGIS surface runoff model for the two periods. This model presents a hydrological parameter that can be used to describe the potential surface runoff depth for drainage areas, and is a function of land cover, soil type, slope and rainfall surplus. CN values were first imported into the model as an Excel file from the potential runoff coefficient tables (Tables 2 and 3). These tables were developed for runoff values based on soil type, land cover and slope degree in previous research [66], and discretise surface slope into four classes based on those values. The values in the two tables are taken from the literature [67–70]. Finally, the annual surface runoff depth was derived for the two periods rather than obtaining an event runoff coefficient for the annual rainfall surplus.


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)

Factors considered in the determination of surface runoff depth: (A) land cover 1990, (B) land cover 2000, (C) rainfall surplus, (D) slope and (E) soil texture.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0125805.g003: Factors considered in the determination of surface runoff depth: (A) land cover 1990, (B) land cover 2000, (C) rainfall surplus, (D) slope and (E) soil texture.
Mentions: Land cover data are required to achieve baseline climate data, and can also be used to assess the effects of land cover changes and other climate variables in an area’s hydrological response. In the study reported herein, the factors considered in determining the surface runoff depth (see Fig 3) were (1) the land cover map in 1990, (2) land cover map in 2000, (3) rainfall surplus (long-term annual average), (4) slope degree map and (5) soil texture. These factors were also used to develop an ArcGIS surface runoff model for the two periods. This model presents a hydrological parameter that can be used to describe the potential surface runoff depth for drainage areas, and is a function of land cover, soil type, slope and rainfall surplus. CN values were first imported into the model as an Excel file from the potential runoff coefficient tables (Tables 2 and 3). These tables were developed for runoff values based on soil type, land cover and slope degree in previous research [66], and discretise surface slope into four classes based on those values. The values in the two tables are taken from the literature [67–70]. Finally, the annual surface runoff depth was derived for the two periods rather than obtaining an event runoff coefficient for the annual rainfall surplus.

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