scholarly journals Green, Green Grass of Home

Te Kaharoa ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Te Atamea Boynton
Keyword(s):  
Gravel Road

Our old grey Subaru crept slowly up the dusty gravel road. It was a muggy evening, but you couldn’t turn the air con on or open any windows unless you wanted a car full of dust. I got to sit in the front for this last stretch to Nanny’s, so I oversaw switching out Dad's Prince Tui Teka CDs. Dad went extra slow so as not to scratch the discs, but that was hard on a gravelly road full of potholes.

scholarly journals Consequences of permafrost degradation for Arctic infrastructure – bridging the model gap between regional and engineering scales

2021 ◽  
Vol 15 (5) ◽  
pp. 2451-2471
Author(s):  
Thomas Schneider von Deimling ◽  
Hanna Lee ◽  
Thomas Ingeman-Nielsen ◽  
Sebastian Westermann ◽  
Vladimir Romanovsky ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Strong Increase ◽  
Permafrost Degradation ◽  
Key Factors ◽  
The Road ◽  
Model Based ◽  
Linear Infrastructure ◽  
Continuous Permafrost ◽  
Gravel Road

Abstract. Infrastructure built on perennially frozen ice-rich ground relies heavily on thermally stable subsurface conditions. Climate-warming-induced deepening of ground thaw puts such infrastructure at risk of failure. For better assessing the risk of large-scale future damage to Arctic infrastructure, improved strategies for model-based approaches are urgently needed. We used the laterally coupled 1D heat conduction model CryoGrid3 to simulate permafrost degradation affected by linear infrastructure. We present a case study of a gravel road built on continuous permafrost (Dalton highway, Alaska) and forced our model under historical and strong future warming conditions (following the RCP8.5 scenario). As expected, the presence of a gravel road in the model leads to higher net heat flux entering the ground compared to a reference run without infrastructure and thus a higher rate of thaw. Further, our results suggest that road failure is likely a consequence of lateral destabilisation due to talik formation in the ground beside the road rather than a direct consequence of a top-down thawing and deepening of the active layer below the road centre. In line with previous studies, we identify enhanced snow accumulation and ponding (both a consequence of infrastructure presence) as key factors for increased soil temperatures and road degradation. Using differing horizontal model resolutions we show that it is possible to capture these key factors and their impact on thawing dynamics with a low number of lateral model units, underlining the potential of our model approach for use in pan-Arctic risk assessments. Our results suggest a general two-phase behaviour of permafrost degradation: an initial phase of slow and gradual thaw, followed by a strong increase in thawing rates after the exceedance of a critical ground warming. The timing of this transition and the magnitude of thaw rate acceleration differ strongly between undisturbed tundra and infrastructure-affected permafrost ground. Our model results suggest that current model-based approaches which do not explicitly take into account infrastructure in their designs are likely to strongly underestimate the timing of future Arctic infrastructure failure. By using a laterally coupled 1D model to simulate linear infrastructure, we infer results in line with outcomes from more complex 2D and 3D models, but our model's computational efficiency allows us to account for long-term climate change impacts on infrastructure from permafrost degradation. Our model simulations underline that it is crucial to consider climate warming when planning and constructing infrastructure on permafrost as a transition from a stable to a highly unstable state can well occur within the service lifetime (about 30 years) of such a construction. Such a transition can even be triggered in the coming decade by climate change for infrastructure built on high northern latitude continuous permafrost that displays cold and relatively stable conditions today.

scholarly journals Analysis of Gravel Road Problems in Ethiopia Mountainous Terrain

2016 ◽  
Vol 4 (4) ◽  
pp. 153-162
Author(s):  
Fikreyesus Demeke ◽  
Alemayehu Gebissa
Keyword(s):  
Mountainous Terrain ◽  
Gravel Road

Transportation Planning through Pavement Performance Prediction Modeling for Botswana Gravel loss Condition

2012 ◽  
Vol 256-259 ◽  
pp. 2976-2982
Author(s):  
Adewole Oladele ◽  
Vera Vokolkova ◽  
Jerome Egwurube
Keyword(s):  
Performance Prediction ◽  
Rural Areas ◽  
Transportation Planning ◽  
Transportation Network ◽  
Road Networks ◽  
Small Population ◽  
Road Transportation ◽  
Feed Forward Neural Network ◽  
Pavement Performance Prediction ◽  
Gravel Road

Botswana is a Southern African country with an area of about 582,000 sq. km and its small population of about 2 million people. The road transportation network has grown beyond all expectations since independence in 1966. Out of the 18,300 km Botswana Public Highway Networks, gravel road networks are significant in providing access to rural areas where the majority of the population lives. Modelling of gravel loss conditions are required in order to predict their conditions in the future and provide information on the manner in which pavements perform. Such information can be applied to transportation planning, decision making processes and identification of future maintenance interventions. The results of previous attempts to develop gravel loss condition forecasting models using multiple linear regression (MLR) approach have not been reliable. This paper intended to develop accurate and reliable performance models which best capture the effects of gravel loss condition influencing factors using Feed Forward Neural Network (FFNN) modeling technique. As extension of knowledge in unpaved road transportation network, FFNN trained with Levenberg-Marquardt (L-M) method was used to develop gravel loss performance prediction model for Botswana gravel road networks to achieve a reliable result of a higher coefficient of determinant R2 = 0.94 compared with MLR analysis of R2 = 0.74.

Optimizing Low-Volume Road Network Performance Through Improved Management, Design, and Construction

2003 ◽  
Vol 1819 (1) ◽  
pp. 299-305 ◽  
Author(s):  
G. D. Van Zyl ◽  
M. G. Henderson ◽  
H. G. Fourie
Keyword(s):  
Management System ◽  
Road Network ◽  
Performance Monitoring ◽  
Systems Design ◽  
Western Cape ◽  
Road Management ◽  
Gravel Roads ◽  
Low Volume ◽  
Gravel Road ◽  
Design And Construction

The Provincial Administration of the Western Cape in South Africa is responsible for 18,900 km of proclaimed roads, of which 10,500 km are unsurfaced. A formal gravel road management system has been in operation since 1989 that assists in prioritizing projects for regraveling and upgrading gravel roads to surfaced standards. Because of fund limitations for upgrading gravel roads to surfaced roads, there is a need to optimize performance of the gravel road network and maximize use of knowledge and latest research results for southern Africa. Staff shortages and loss of in-house expertise made external assistance necessary to improve service to road users. Processes formalized, implemented, and planned for this purpose included ( a) upgrading the gravel road management system to quantify benefits, prioritize activities, and select maintenance and improvement measures; ( b) appointing consulting engineers in each district to help manage borrow pits, materials design, training, construction supervision and quality control, maintenance planning and control, and performance monitoring; ( c) communication about project priorities, construction programs, work methods, construction team performance, and activity costs; and ( d) development of an operational web-enabled system to manage all activities related to unsurfaced roads. Within 1 year, a remarkable difference in gravel road performance was observed without a significant reduction in productivity. Total transportation costs were lowered with only a marginal increase in agency costs. Continuous communication among system operators, design engineers, project managers, and construction teams is considered one of the most important aspects in optimizing performance of the Western Cape low-volume road network. This study highlights the most important changes in management, systems, design, and construction and the practical innovations responsible for the successes achieved as a potentially valuable aid to those involved with providing and maintaining low-volume roads.

“THERE WERE GIANTS IN THOSE DAYS”

2001 ◽  
Vol 12 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Kent V. Flannery
Keyword(s):  
Bypass Surgery ◽  
Near Drowning ◽  
Heart Attacks ◽  
Maya Mountains ◽  
Gravel Road

On January 16, 2001, on a gravel road in the Maya Mountains of Belize, one of archaeology's most prolific and colorful superstars was fatally injured in the crash of his rental car. Having endured for 82 years despite cancer, heart attacks, a near-drowning, and double bypass surgery, the seemingly indestructible “Scotty” MacNeish was taken from us by accident. Had he lasted 102 years, I would still consider his death premature.

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