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Item Open Access Relationship between 20th Century Dune Migration and Wetland Formation at Cape Cod National Seashore, Massachusetts(Nazarbayev University School of Engineering and Digital Sciences, 2006-05) Sagin, JayOuter Cape Cod (Massachusetts) is dominated by active and stabilizing parabolic and transverse dunes interspersed with numerous inter-dune wetlands. Dune migration has been significantly affected by human activities; conversely, current dune movements are affecting local populations. The objective of the reported research was to assess, using remote sensing and geographic information systems (GIS) technologies, migration of the Cape Cod dunes and the effect of dune movement on distribution of associated wetlands. Aerial photographs from 1938 through 2003 were analyzed to track individual dune movements and subsequent wetland propagation and expansion. Absolute dune movement rates during this period were computed, with a plot of dune movement as a cumulative function. One sub-problem of this study was to quantify ‘white’ areas of active moving sand and ‘dark’ areas of vegetation, in order to quantify changes in vegetative cover with wetland propagation and, conversely, vegetative disappearance with dune movement. Attempts were made to correlate the Palmer Drought Severity Index (PDSI) with dune migration. Based on review of aerial photographs, parabolic dunes have migrated 150 to 250 m since 1938, with 60% of the movement occurring between 1938 and 1977. The relation between absolute parabolic dune migration and corresponding PDSI is approximately logarithmic. Maximum dune migration is associated with PDSI values lower than –2 and reflects moderate drought conditions. Wetlands consistently trailed the dunes, and the distance of wetland movement was related to dune movement distances. Wetland migration was particularly marked from the 1950s to the 1980s. Based on review of georeferenced aerial photographs, it is concluded that marked stabilization of Cape Cod dunes occurred in the 1980s and 1990s, with renewed movement in the 21st Century. This study provides a practical application for assessment of dune migration and vegetative transformations over time using remote sensing and GIS technologiesItem Open Access Integrated Approach for the Assessment and Development of Groundwater Resources in Arid Lands: Applications in the Quetta Valley, Pakistan(Nazarbayev University School of Engineering and Digital Sciences, 2010-12) Sagin, JayThe lack of adequate field measurements (e.g., precipitation and stream flow) and difficulty in obtaining them often hampers the construction and calibration of rainfallrunoff models over many of the world’s watersheds, leaving key elements of the hydrologic cycle unconstrained. We adopted methodologies that rely heavily on readily available remote sensing datasets as viable alternatives and useful tools for assessing, managing, and modeling the water resources of such remote and inadequately gauged regions. The Soil and Water Assessment Tool was selected for continuous (1998–2005) rainfall-runoff modeling of the northeast part of the Pishin Lora basin (NEPL), a politically unstable area that lacks adequate rain gauge and stream flow data. To account for the paucity of rain gauge and stream flow gauge data, input to the model included satellite-based Tropical Rainfall Measuring Mission TRMM precipitation data. Modeled runoff was calibrated against satellite-based observations including: (1) monthly estimates of the water volumes impounded by the Khushdil Khan (latitude 30° 40'N, longitude 67° 40'E) and the Kara Lora (latitude 30° 34'N, longitude 66° 52'E) reservoirs, and (2) inferred wet versus dry conditions in streams across the NEPL throughout this period. Calibrations were also conducted against observed flow reported from the Burj Aziz Khan station at the NEPL outlet (latitude 30°20'N; longitude 66°35'E). Model simulations indicate that (1) average annual precipitation (1998–2005), surface runoff, and net recharge are 1,300 × 106 m3, 148 × 106 m3, and 361 × 106 m3, respectively; (2) within the NEPL watershed, precipitation and runoff are high for the northeast (precipitation: 194 mm/year; runoff: 38 × 106 m3/year) and northwest (134 mm/year; 26 × 106 m3/y) basins compared to the southern basin (124 mm/year; 8 × 106 m3/year); and (3) construction of delay action dams in the northeast and northwest basins of the NEPL could increase recharge from 361 × 106 m3/year up to 432 × 106 m3/year and achieve sustainable extraction. The adopted methodologies are not a substitute for traditional approaches that require extensive field datasets, but they could provide first-order estimates for rainfall, runoff, and recharge in the arid and semi-arid parts of the world that are inaccessible and/or lack adequate coverage with stream flow and precipitation data.Item Open Access Boundary layer receptivity and resonance caused by tuned disturbances within cascade flows(Nazarbayev University School of Engineering and Digital Sciences, 1997-05-10) Rojas-Solorzano, L.The receptivity and stability of steady non-separated and unsteady separated boundary layers in a two-dimensional airfoil cascade flow is investigated by Direct Numerical Simulation of the time-dependent Navier-stokes and continuity equations. The study includes the effects caused by the introduction of free-steam time-harmonic disturbances. The calculation of the transport, generation and dissipation of Fluctuating Kinetic Energy is introduced as a non-classical technique in the analysis