Urban ecology and related environmental concerns
S.H. Raza; M. Shafique; M. Zia-ur-Rehman; A. Sikandar; N. Ahmad; K. Shah
Abstract
Water loss can be minimized and conserve through constructing small storage dams for various irrigation purposes to support local livelihood. Geographic information system provides powerful techniques for many hydrological modeling and suitable dam site selection. The current study explored potential ...
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Water loss can be minimized and conserve through constructing small storage dams for various irrigation purposes to support local livelihood. Geographic information system provides powerful techniques for many hydrological modeling and suitable dam site selection. The current study explored potential sites for small storage dams to meet agricultural requirements in district Malakand, Khyber Pukhtunkhwa. Multi criteria decision analysis was used for selection of suitable sites for storage dam for agricultural purpose. The methodology was completed in four main steps; acquisition of data, selection of factors and constraints, giving percentage influence to each criterion and performing weighted overlay. Digital elevation model was used for watershed analysis and Landsat 8 image for land use classification. All contributing factors such as slope, soil map, settlements, canals, roads, river, watershed and recreational sites were used in weighted overlay for suitable site selection. Results showed that Masooka rockland soil possessed the highest suitability for dam construction as the high clay proportion of the soil provides cementation. Slope zone of 0-3.16 degree slope was considered best and 3.16-7.90 degrees was highly suitable. Distance (5-10 km or more) form recreational sites and presence of 140-186 Stream links which makes the site more suitable. Regarding land use, the barren land or rangeland was more preferable. Finally, 15 sites were found suitable for small storage dams in the district. The main river lies close to the selected site assuring the perennial flow of water. The study suggests that geographic information system provides efficient tools for decision makers in hydrology and dam site selection.
Urban ecology and related environmental concerns
A.B. Imran; S. Ahmed
Abstract
Forest ecosystems are among the largest terrestrial carbon reservoirs on our planet earth thus playing a vital role in global carbon cycle. Presently, remote sensing techniques provide proper estimates of forest biomass and quantify carbon stocks. The present study has explored Landsat-8 sensor product ...
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Forest ecosystems are among the largest terrestrial carbon reservoirs on our planet earth thus playing a vital role in global carbon cycle. Presently, remote sensing techniques provide proper estimates of forest biomass and quantify carbon stocks. The present study has explored Landsat-8 sensor product and evaluated its application in biomass mapping and estimation. The specific objectives were estimation of above ground biomass and carbon stocks using field data, assessing relationships of Landsat-8 spectral indices and field data and modeling of biomass and carbon stocks based on best linear regression model. Results showed that the highest aboveground biomass and below ground biomass was recorded as 246 t/ha and 64 t/ha whereas the lowest aboveground biomass and below ground biomass was 55 t/ha and 14 t/ha, respectively. Similarly, the highest above ground carbon and below ground carbon (t/ha) were 116 t/ha and 30 t/ha respectively while the lowest above ground carbon and below ground carbon (t/ha) were estimated as 26 t/ha and 6.7 t/ha respectively. Indices computed from Landsat-8 included normalized difference vegetation index, difference vegetation index, soil adjusted vegetation index, perpendicular vegetation index and atmospherically resistant vegetation index. Regarding relationship between aboveground biomass and vegetation indices, the coefficient of correlation (R2) were 0.67, 0.68, 0.65, 0.58 and 0.23 for normalized difference vegetation index, soil adjusted vegetation index, Perpendicular vegetation index, difference vegetation index and atmospherically resistant vegetation index respectively. The stepwise correlation between aboveground biomass (dependent variable) and five indices (Normalized difference vegetation index; soil adjusted vegetation index; Perpendicular vegetation index; difference vegetation index; atmospherically resistant vegetation index). Among five vegetation indices, only soil adjusted vegetation index was selected in stepwise method, satisfying the criteria and the overall model R2 was 0.63 and its adjusted R2 was 0.60. Simple linear regression model between aboveground biomass and single predictor index was better than stepwise regression model with (R2= 0.68) and (Root mean square error = 33.75 t/ha). Thus, soil adjusted vegetation index was considered best for biomass mapping. The study concluded that Landsat-8 product has considerable potential for biomass and carbon stocks estimation and can be expanded to national and regional forest inventories, modeling and future reducing emission from deforestation and forest degradation+ implementation.
