Monitoring Sand Drift Potential and Sand Dune Mobility over the Last Three Decades (Khartouran Erg, Sabzevar, NE Iran)

Aeolian sediments cover about 6% of the earth’s surface, of which 97% occur in arid regions, and these sediments cover about 20% of the world’s lands. Sand drifts can harm sensitive ecosystems; therefore, this research has aimed to study wind regimes and the monitoring of sand drift potential and dune mobility in the Khartouran Erg (NE Iran). The study investigated 30 years of wind speed and direction to better understand sand dune mobility processes using the Fryberger and Tsoar methods. The results of the wind regime study showed that the eastern (33.4%) and northeastern (14.3%) directions were more frequent, but the study of winds greater than the threshold (6 m/s) in winter, spring, and autumn indicated the dominance of eastern and northern wind directions. Findings of calm winds showed that winters (40.4%) had the highest frequency, and summers (15%) had the lowest frequency; the annual frequency was 30%. The average wind speed in summers was the highest (4.38 m/s), and, in the winters, it was the lowest (2.28 m/s); the annual average wind speed was 3.3 m/s. The annual drift potential (DP = 173 VU) showed that it was categorized as low class, and the winds carried sand to the southwest. The monitoring of drift potential showed that there was a sharp increase between 2003 and 2008, which could have been attributed to a change in wind speeds in the region. Unite directional index, the index of directional variability, has been alternating from 0.3 to 0.6 for 30 years. Furthermore, monitoring of sand mobility recorded a value from 0.1 to 0.4, and the lowest and highest values were registered from 0.08 to 0.9, with an average of 0.27. Finally, it can be concluded that sand dunes have been fixed for a long time, and the intensity of the mobility index is affected by climate changes.

Sand Drift and Measures to Mitigate Its Impact on the Railway Track

This research provides an analytical review of measures to mitigate the impact of winds and flow on a railway track based on publications in English, Russian, French, Chinese and Spanish, identifies general and specific experience in the application of measures in a socio-geographical context, consistently sets out their physical and technical characteristics and advantages and disadvantages of technological solutions, identified prospects for further research to improve their technical, technological and economic efficiency.

Holocene sediment budget for wave-dominated Moruya coastline, southeastern Australia: sediment sources, transport and embayment interconnectivity

<p>Sediment budgets on wave-dominated coastlines are important in understanding shoreline behaviour. Coastal sediment compartments provide a means to investigate sediment budgets over a range of time and space scales. This study reconstructs the sediment budget over the mid- to late- Holocene for a secondary coastal compartment on the New South Wales (NSW) south coast ~26 km in length and containing five adjacent but discrete barriers: Barlings Beach, Broulee Beach, Bengello Beach, Moruya Heads Beach and Pedro Beach. Building upon existing morphostratigraphic studies in this region, a new set of Optically Stimulated Luminescence (OSL) ages are reported for foredune ridge successions at previously un-dated sites. Additional Ground Penetrating Radar (GPR) transects complement earlier stratigraphic data, and topographic and bathymetric LiDAR datasets capture the morphology of subaerial coastal deposits and the inner shelf. The results demonstrate two different sediment sources promoting shoreline progradation and coastal barrier construction. A quartz-rich sand, transported onshore from the shoreface as it evolved towards equilibrium, dominates the barrier sequences. Skeletal carbonate sand augmented the quartz sand supply for the northern Barlings and Broulee beaches after ~3000 years ago. Shoreline progradation at Bengello Beach was steady throughout the mid-to late- Holocene. Bengello Beach contains the largest volume of Holocene sand and accreted at an average rate of 3.1 m<sup>3</sup>/m/yr (for the current shoreline length). Changes in sediment accumulation rate has occurred for the other barrier systems as their shorelines prograded resulting in changes to their alongshore interconnectivity. Rapid infilling of the Pedro Beach embayment by ~4000 years ago initiated headland bypassing northwards to Moruya Heads Beach which only then commenced progradation. In contrast, as Broulee and Bengello Beaches prograded, a tombolo formed in the lee of Broulee Headland which restricted northward sand drift into the Broulee embayment. As these once continuous shorelines became two, a marked increase in skeletal carbonate content at Broulee occurred attesting to shoreline separation and independence of sediment budget. This study emphasises the importance of quantifying the long-term temporal variability in sediment budget and embayment interconnectivity in order to better understand shoreline response to contemporary anthropogenic influences and changing boundary conditions such as sea level and wave climate.</p>

The problem of sand drifts on railways

The sand drift of the railway track and the blowing of the roadbed negatively affect the elements of the track infrastructure to such an extent that they reach the limit states at which it becomes impossible for them to continue functioning. This leads to a violation of train safety. To assess the negative impact of sand and determine the necessary protective measures, a method of visual monitoring of the state of the track is proposed.

Managing Coastal Sand Drift in the Anthropocene: A Case Study of the Manawatū-Whanganui Dune Field, New Zealand, 1800s–2020s

In the Anthropocene, dunes act as a natural defence from sea-level rise and storm surges while providing ‘ecosystem’ services. This article uses scientific and historical data to examine the Manawatū-Whanganui dune field in New Zealand from the nineteenth to the twenty-first century. Dunes that were destabilised due to European settlements and their activities were drifting inland causing social, economic and political problems. Attempts to prevent dune mobility occurred at the time in many parts of the world. Thus, knowledge was shared between countries through experts and migrants. The consequences of the implemented solutions and new environmental conditions mean that dunes are still a major issue in the region. A comparative analysis of historical and present-day dune management practices provides a better understanding of long-term dune drift. In conclusion, interdisciplinary analyses of long-term relations between dunes and society must be taken into account for their holistic management.

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

Records of climate changes and anthropogenic actions over dune fields in historical times

<p>Coastal dunes are very complex systems and very sensitive to climatic variability and human actions. In Portugal, coastal dune fields have undergone major changes over historical times. The aim of the paper is focused on the coastal dune systems evolution over the last five centuries, natural and man induced (namely by deforestation and afforestation) and their transformation under the present global changes (sea level rise and coastal storms). The analysis of historical records and environmental data using a set of proxies recorded over the last 1,000 yrs, show intense aeolian activity and sand drift episodes during Little Age Period, causing serious problems for human settlements and agriculture. Coastal society have responded to the wind-blown sands fixing the dunes through afforestation. The process is well documented in the historical sources and many management measures, including abundant legislation, projects and reports were carried out by Portuguese authorities to avoid sand incursion inland.  According to the main report of the General Forest Administration, in the final of 18th century, was estimated an area of about 72 000 ha of free aeolian sands in need of afforestation. Thus, along Portuguese coastline, the dunes experienced a period of stability during the 20th century, due to planting of grasses and pine forest. This paper examines the pathways of the transgressive dune fields of the Central Western Portuguese coast, over various stages of coastal evolution. Mapping the morphological features between Mondego river mouth and Nazaré, using a combination of satellite images, aerial photographs and Lidar data we identified distinct phases of aeolian activity and landforms modification that were associated to climatic fluctuations. This coastal dune system is composed by a succession of different aeolian phases, including a littoral foredune, which lies inland with a complexity of morphologies with transverse and crescentic ridges, and also parabolic dunes. The results show that the dunes building and sand migration inland appears to be linked to the conditions of predominantly negative winter North Atlantic Oscillation index (NAOi), driven by climatic variability during Holocene/Antrhopocene. The consistency of intense sand drift episodes with abrupt cold events during Little Age Period, drastically reduced the area occupied by vegetation, causing changes in aeolian sedimentary processes. Thus, it seems that coastal dunes evolution over the past centuries have been controlled by the two-way interactions between natural conditions and human activities, shaping the Portuguese coastline. Placing historical evidence in a geographical perspective, we hope to fill the gaps in coastal zone dynamics, providing new insights of the human-landscape relationships to predict the future response of the coastal dune systems to human pressure and climate change.<br>Key-words: coastal dunes evolution, geomorphological features, sand drift, anthropogenic impacts, climatic fluctuation, Western Portugal.</p>

A DPSIR analysis of aeolian sand dune mobilization along the coast of Manawatu-Wanganui in New Zealand

<p>Coastal sand dunes are multifunctional landscapes with rich biodiversity and provide ecological goods and services. They play a dual role as a sediment sink or a source to maintain the long-term stability of a coastal system. These landscapes have been affected by human settlements, economic activities and recreational purposes. Sand dunes in the Manawatu-Wanganui region, in New Zealand, have been subjected to such forcings during Maori settlements and, in particular, since the establishment of Europeans since 1840. Consequently, dunes have evolved from a transgressive system to a parabolic one, while the rate of dune drifting is still observed to be one of the highest in the world.</p><p>Because this was a problem for populations living in the area, there were several attempts to arrest dune drifting. Using the Driver-Pressure-State-Impact-Response (DPSIR) cyclic framework, we analyzed these interventions during two-time frames: 1) from the 19th to 20th century and 2) during the early 21st century. We checked for data in historical records and literature including the Parliamentary debates of New Zealand. Historical evolutionary trends were inferred by analyzing a series of maps since 1773. The present-day impacts were derived from a series of georeferenced google images from 1983 using the ESRI ArcGIS tools. The coastal management responses were obtained through scientific literature and reports of the Horizon Regional Council.</p><p>According to the analysis, drivers of dune drift before the 21st century were 1) settlements resulting in burning shrubs, deforestation, grazing, agriculture, mining, and building, 2) introduction of non-native animals. The pressures were: 1) mobile dunes and 2) blowouts. The assessment of the state of the environment included: 1) soil fertility, 2) habitat quality, 3) river navigability and 4) air quality. The assessed impacts were 1) increase of wasteland and loss of fertility, 2) foredune erosion, 3) impact on transportation and 4) creation of swamps as river mouths were closed. The management responses included 1) introduction of 1903 and 1908 Sand Drift acts for reclamation of affected areas, 2) introduction of exotic vegetation (e.g. Marram grass) and 3) foredune building using sand trapping fences.</p><p>The main drivers of the 21st century are 1) intensive urbanization, 2) introduction of exotic vegetation and 3) global fossil fuel burning. The invasive character of marram resulted in the loss of biodiversity. The coastline erosion due to sea-level rise during the 21st century will be moderated due to its progradational nature. The study revealed a significant spatial variability of the rate of dune drift. The responses include 1) a consolidated “One Plan” as mandated by 1991 Resource Management Act; 2) removal of exotic vegetation to support native biodiversity by enhancing natural processes of dunes (a paradigm shift in dune management); 3) enhancing awareness while encouraging the public participation in mitigating measures.</p><p>In conclusion, historical data combined with DPSIR framework tools showed that management interventions should be implemented considering long-term and interdisciplinary analysis to better understand the systems’ evolution and the full consequences of human actions.</p>