Articles
1. The twentieth-century migration of parabolic dunes and wetland formation at Cape Cod National Sea Shore, Massachusetts, USA: landscape response to a legacy of environmental disturbance
Steven L. Forman, Zhanay Sagintayev, Mohamed Sultan, Stephen Smith, Richard Becker, Margaret Kendall and Liliana Marìn
The Holocene 2008; 18; 765
DOI: 10.1177/0959683608091796
Abstract: Cape Cod, an early North American colony, was covered by mature forest prior to European contact but, with settlement in the late seventeenth century, aeolian processes dominated into the twenty-first century. An aerial photographic time series from AD 1938 to 2003 quantifies dune movement that reflects processes over centuries and documents accelerated parabolic dune movement at ~4 m/yr from 1938 to 1977 during a drier interval. In contrast, dune movement between 1987 and 2003 slowed to ~1 m/yr with wetter conditions. Wetlands expand post dune movement often forming in dune blowouts with seasonally wet conditions. Stratigraphic studies, coupled with optically stimulated luminescence ages, place erosion and burial of the presettlement forest soil by migrating dunes at AD 1690 ± 40 yr, with aeolian deposition continuing into the nineteenth and twentieth centuries, consistent with the historic record of land surface conditions. A threshold of landscape stability was exceeded in the late seventeenth to early eighteenth centuries, indicated by dune formation in response to human-induced land-cover changes, concomitant severe droughts and exposure to tropical storm/hurricane wind field. Dune orientation indicates preferential movement during winter with winds dominantly from the W–NW and with reduced vegetation cover. The present high biodiversity in interdunal wetlands is a legacy of aeolian processes from landscape disturbance initiated by European settlers in the seventeenth century.
Key words: Holocene aeolian activity, parabolic dunes, wetland formation, remote sensing, Cape Cod, historic landscape disturbance, Massachusetts.
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2. Geochemical, isotopic, and remote sensing constraints on the origin and evolution of the Rub AL Khali aquifer system, Arabian Peninsula
M. Sultan a, N. Sturchio, S. Al Sefry, A. Milewski, R. Becker, I. Nasr, Z. Sagintayev
doi:10.1016/j.jhydrol.2008.04.001
Abstract: Chemical and stable isotopic compositions of groundwater samples from the Rub Al Khali (RAK) in southern Saudi Arabia were analyzed. Samples were collected from wells of variable depth (1.5–800 m) along the perimeter of the eastern half of the RAK including flowing artesian wells, pumped wells (formerly artesian), and shallow handdug wells encompassing those in sabkha areas. Data indicate that the water from the artesian and formerly artesian wells represents the contents of confined aquifers. Such water (Group 1) is isotopically depleted (δ2 H values ranging from 60‰ to 35‰), and has total dissolved solids (TDS) concentrations ranging from 1300 to 76,000 mg/L, indicating that much of the salinity is acquired in the subsurface. Water from shallow hand-dug wells including those in sabkha areas (Group 2) has experienced significant evaporation (δ2 H values ranging from 34‰ to +19‰) as well as salinization (TDS as high as 92,000 mg/L) by dissolution of sabkha salts including halite and gypsum. Stable isotope data for the Group 2 water samples define an evaporation trend line originating from the Group 1 water samples. This relationship indicates that the Group 2-type water evolved from Group 1-type water by ascending through structural discontinuities, dissolving evaporative salts, and undergoing substantial near-surface evaporation in groundwater discharge zones (sabkhas) characterized by shallow groundwater levels (<2 m). This interpretation is supported by the relatively unradiogenic Sr isotope ratios of groundwater samples (Sr87/Sr86 = 0.70771–0.70874) that are inconsistent with that of modern seawater (87Sr/86Sr = 0.70932). The RAK aquifer water represents either high-elevation recharge from the Red Sea Hills, and/or recharge largely formed of paleo-water precipitated during moist climate intervals of the late Pleistocene recharging aquifers cropping out at the foothills of the Red Sea mountains. This inference is supported by a progressive decrease in hydraulic head and increase in groundwater salinity from west to east, substantial precipitation over the Red Sea Hills, and a major E–W trending channel network that channels precipitation from the Red Sea Hills toward recharge areas. Analysis of 3-hourly TRMM (Tropical Rainfall Measuring Mission: 1998–2006) precipitation data and digital elevation data shows that 27% of the average annual precipitation (150 х109 m3 ) over the Arabian Peninsula is channeled toward the recharge zone of the RAK aquifer system, of which an estimated 4 х 109 m3 a-1 to 10 х 109 m3 a-1 of this water is partitioned as recharge to the RAK aquifer system. Additional integrated studies on recharge rates, sustainability, and water quality issues for the RAK aquifers could demonstrate that the RAK is one of the most promising sites for groundwater exploration in the Arabian Peninsula. Results highlight the importance of investigating the potential for sustainable exploitation of similar large aquifer systems that were largely recharged in previous wet climatic periods yet are still receiving modest modern meteoric contributions.
Key words: Saudi Arabia; Rub Al Khali; Red sea hills; Groundwater recharg and discharge; Tropical rainfall measuring mission; Oxygen, hydrogen, and strontium isotopes
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3. Trace element geochemistry of groundwater from Quetta Valley, western Pakistan
Shuhab D. Khan, Khalid Mahmood, Mohamed I. Sultan, Abdul S. Khan, Yingqian Xiong, Zhanay Sagintayev
DOI 10.1007/s12665-009-0197-z
Abstract: This manuscript presents major, minor and trace elements data for groundwater samples collected from wells, tube wells, springs and karezes from Quetta Valley. Quetta Valley in Pakistan has frequently experienced shortage of groundwater. In recent years, the water quality has had a sharp decline at many locations. The study of groundwater resources in this valley is an attempt to understand the causes of and sources of contamination. At several locations, nitrate, sulfate, arsenic, selenium, chromium and nickel contamination has been determined. The preliminary results indicate that these contaminations apparently result from a combination of rock alteration and mining activity in the area. Different water sources could have also contributed to the deterioration of the water quality of Quetta Valley. This research provides the basis for future work, which will involve detailed hydrological modeling and water quality studies.
Keywords: Groundwater chemistry, Trace elements, ICP-MS, Arsenic, Ultramafic rocks
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4. A remote sensing contribution to hydrologic modelling in arid and inaccessible watersheds, Pishin Lora basin, Pakistan
Z. Sagintayev, M. Sultan, S. D. Khan, S. A. Khan, K. Mahmood, E. Yan, A. Milewski, and P. Marsala
DOI: 10.1002/hyp.8114
Abstract: The lack of adequate field measurements often hampers the construction and calibration of rainfall-runoff models over many of the world’s watersheds. We adopted methodologies that rely heavily on readily available remote sensing datasets as viable alternatives for assessing, managing, and modelling of such remote and inadequately gauged regions. The Soil and Water Assessment Tool was selected for continuous (1998–2005) rainfall-runoff modelling of one such area, the northeast part of the Pishin Lora basin (NEPL). Input to the model included satellite-based Tropical Rainfall Measuring Mission precipitation data, and modelled runoff was calibrated against satellite-based observations, the latter included: (i) 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 (ii) inferred wet versus dry conditions in streams across the NEPL. 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 (i) average annual precipitation (1998–2005), runoff and recharge in the NEPL are 1300 x 106 m3, 148 x 106 m3, and 361 x 106 m3, respectively; (ii) within the NEPL watershed, precipitation and runoff are high for the northeast (precipitation: 194 mm/year; runoff: 38 x106 m3/year) and northwest (134 mm/year; 26 x 106 m3/year) basins compared to the southern basin (124 mm/year; 8 x106 m3/year); and (3) construction of delay action dams in the northeast and northwest basins could increase recharge from 361 x 106 m3/year up to 432 x 106 m3/year and achieve sustainable extraction. The adopted methodologies are not a substitute for traditional approaches, 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 field data. Copyright 2011 John Wiley & Sons, Ltd.
KEY WORDS: Pishin Lora basin; Balochistan; Pakistan; continuous rainfall-runoff model; soil water assessment tool; remote sensing
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5. Red Sea rifting controls on aquifer distribution: Constraints from geochemical, geophysical, and remote sensing data
M. Sultan, A.F. Yousef, S.E. Metwally, R. Becker, A. Milewski, W. Sauck, N.C. Sturchio, A.M.M. Mohamed, A. Wagdy, Z. El Alfy, F. Soliman, M. Rashed, D. Becker, Z. Sagintayev, M. Ahmed, and B. Welton
doi: 10.1130/B30146.1
ABSTRACT: Highly productive wells in the Central Eastern Desert of Egypt are tapping groundwater in subsided blocks of Jurassic to Cretaceous sandstone (Taref Formation of the Nubian Sandstone Group) and Oligocene to Miocene sandstone (Nakheil Formation), now occurring beneath the Red Sea coastal plain and within the proximal basement complex. Aquifer development is related to Red Sea rifting: (1) rifting was accommodated by vertical extensional displacement on preexisting NW-SE– to N-S–trending faults forming a complex array of half-grabens and asymmetric horsts; and (2) subsided blocks escaped erosion accompanying the Red Sea–related uplift. Subsided blocks were identified and verified using satellite data, geologic maps, and field and geophysical investigations. Interpretations of very low frequency (VLF) measurements suggest the faults acted as conduits for ascending groundwater from the subsided aquifers. Stable isotopic compositions (δD: –19.3‰ to –53.9‰; δ18O: –2.7‰ to –7.1‰) of groundwater samples from these aquifers are interpreted as mixtures of fossil (up to 70%) and modern (up to 65%) precipitation. Groundwater volumes in subsided blocks are large; within the Central Eastern Desert basement complex alone, they are estimated at 3 × 109 m3 and 10 × 109 m3 for the Nakheil and Taref Formations, respectively. Results highlight the potential for identifying similar rift-related aquifer systems along the Red Sea–Gulf of Suez system, and in rift systems elsewhere. An understanding of the distribution of Red Sea rift–related aquifers and modern recharge contributions to these aquifers could assist in addressing the rising demands for fresh water supplies and water scarcity issues in the region.
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6. Monitoring the freeze-up and ice cover progression of the Slave River
Apurba Das, Jay Sagin, Joost Van der Sanden, Earl Evans, Henry McKay, and Karl-Erich Lindenschmidt
doi.org/10.1139/cjce-2014-0286
Abstract: River ice is an important component to maintain traditional and cultural lifestyles for the peoples along the Slave River in the Northwest Territories. During the winter a stable ice cover provides a vital transportation link to hunting, trapping, and fishing areas along the river. However, little was known about the Slave River ice cover characteristics and behaviour during the freeze-up and ice cover progression period. RADARSAT-2 satellite and time-lapse camera imagery were used in this study to document the different types of ice and understand the mechanisms of ice cover formation progression along the river during the course of winter. Time-lapse images were analyzed to observe the frazil ice generation and patterns of stable ice cover formation of the Slave River near Fort Smith during freeze-up. RADARSAT-2 images acquired from the Slave River Delta areas captured ice cover flooding due to higher river flows in mid-winter. Field surveys along the river provided insights about the ice cover growth in various sections along the river. Air pockets and layers under the ice cover were also detected during the ice surveys. The variation of water flows during the winter has a great impact on the Slave River ice regime. Increases in discharge cause the ice cover to crack or dislodge from the river banks leading to water seeping onto the ice and flooding it, which has implications for muskrat and beaver populations.
Key words: Slave River, river ice freeze-up, RADARSAT-2 satellite imagery, time-lapse imagery.
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7. The changing water cycle: the Boreal Plains ecozone of Western Canada
A. M. Ireson, A. G. Barr, J. F. Johnstone, S. D. Mamet, G. van der Kamp, C. J. Whitfield, N. L. Michel, R. L. North, C. J. Westbrook, C. DeBeer, K. P. Chun, A. Nazemi, and J. Sagin
doi: 10.1002/wat2.1098
Abstract: The Boreal Plains Ecozone (BPE) in Western Canada is expected to be an area of maximum ecological sensitivity in the 21st century. Successful climate adaptation and sustainable forest management require a better understanding of the interactions between hydrology, climate, and vegetation. This paper provides a perspective on the changing water cycle in the BPE from an interdisciplinary team of researchers, seeking to identify the critical knowledge gaps. Our review suggests the BPE will likely become drier and undergo more frequent disturbance and shifts in vegetation. The forest will contract to the north, though the southern boundary of the ecotone will remain in place. We expect detrimental impacts on carbon sequestration, water quality, wildlife, and water supplies. Ecosystem interactions are complex, and many processes are affected differently by warming and drying, thus the degree and direction of change is often uncertain. However, in the short term at least, human activities are the dominant source of change and are unpredictable but likely decisive. Current climate, hydrological, and ecological monitoring in the BPE are limited and inadequate to understand and predict the complex responses of the BPE to human activities and climate change. This paper provides a case study of how hydrological processes critically determine ecosystem functioning, and how our ability to predict system response is limited by our ability to predict changing hydrology.
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8. Influence of hydrological connectivity on winter limnology in floodplain lakes of the Saskatchewan River Delta, Saskatchewan
Brett D. MacKinnon, Jay Sagin, Helen M. Baulch, Karl-Erich Lindenschmidt, and Timothy D. Jardine
Can. J. Fish. Aquat. Sci. 73: 140–152 (2016) dx.doi.org/10.1139/cjfas-2015-0210
Abstract: Globally, hydrological connectivity between rivers and their floodplains has been reduced by river flow management and land transformation. The Saskatchewan River Delta is North America’s largest inland delta and a hub for fish and fur production. To determine the influence of connectivity on limnology within this northern floodplain, water chemistry and stable isotopes (18O and 2H) were analyzed during the winter of 2014 in 26 shallow lakes along a hydrological gradient. A total of five lake connectivity categories were determined by optical remote sensing imagery of surface water coverage area from years of varying flood intensities. Accuracy of categories was verified by degree of 18O and 2H enrichment within lakes. Both isotopes showed marked successional enrichment between connectivity categories, with more isolated lakes exhibiting greater enrichment. Water chemistry in lakes with greater connectivity to the main channel were characterized by higher pH, dissolved oxygen, nitrates, and sulfates and lower total nitrogen, total phosphorus, and ammonium compared with more isolated lakes.These findings illustrate how connectivity influences water chemistry in northern floodplain lakes and how it might determine the suitability of these lakes as winter refuge for fishes. Additionally, our study provides supporting evidence for the effective use of optical remote sensing imagery, an inexpensive and accessible source of data for researchers,