Living Snow Fences: International Practices

In winter, in the countries with snow covered regions, one of the main tasks of road maintenance is to combat snow deposits, snowpacks and snowdrifts on the roadway. Living snow fences consisting of tree and shrub plantings are among known world practices to protect roads against effects of snow deposits. They are environmentally friendly, durable and have great snow retention capacity. However, there are several constraints regarding application of those practices.The analysis of the design, spacing and planting schemes refers to Russian and foreign living snow fences used to protect highways, considers the features, advantages, and disadvantages of living fences in different countries. Japanese and American designs are reviewed as international experience. The influence of the state of trees on the efficiency of their snow-retaining function has been determined. As a result, the need for monitoring and proper maintenance of existing living snow fences throughout their life cycle was confirmed using the examples of surveys of forest plantations in Kazakhstan and in Volgograd region of the Russian Federation.The author presents promising directions for improving the structures and planting schemes of snow storage living fences, namely, an integrated approach to their design as of a protection not only against snowdrifts, but also against pollutants. Such solutions include the design of protective living fences using only tall shrubs, providing the best blowing of roadside areas and dispersion of contaminants. Another solution is to complement the species planted within living fences with willow and corn. Besides, referring to global climate changes, an important task for modern science has been identified, that is to update the current standards for the design of living fences under the current meteorological conditions.Recommendations on the use of mathematical modelling with the help of computer software are suggested regarding development of new configurations of living fences, assessment of their effectiveness, as well as on the adoption of modern technologies such as video cameras and drones during field tests.

The seasonal dynamics of a High Arctic plant - visitor network: temporal observations and responses to delayed snow melt

Plant - visitor food webs provide important insights into species interactions, and more information about their seasonal dynamics is vital to understanding the resilience of species to external pressures. Studies of Arctic networks can also improve our understanding of species responses to the pressures of climate change. This study provides the first description of a plant – insect visitor network in Svalbard, a High Arctic archipelago already experiencing the consequences of climate change. A subset of the network was collected from experimental plots where the snow melt date was delayed with snow fences. The deep snow plots delayed flowering and we expected this to disrupt plant-visitor interactions compared to ambient snow conditions. However, the composition of flowers and insect visitors were similar between regimes, and the network tracked patterns of overall flowering phenology. Nevertheless, the deep snow significantly reduced the average overlap between flower availability and insect activity, reducing the probability of an interaction. We suggest that at a landscape scale, Arctic pollinators will benefit from patchy changes to snow melt that maintain heterogeneity in the timing of flowering but changes that increase homogeneity in snowmelt across the landscape may negatively impact some species.

Evaluating the Costs and Benefits of Snow Fences in Illinois: Phase 2

Serving as a windbreak, properly sited and designed snow fences have been proven effective in mitigating the negative impacts of blowing snow. To achieve the best snow-control effects, the ideal locations for snow fences are usually outside the roadway right-of-way. Few efforts have been made to examine the economic efficiency of snow fences and explore ways to reward private landowners. The objective of this project was to develop methodologies for evaluation of the costs and benefits of snow fences in Illinois and identify ways to encourage private landowners’ participation in the snow fence program while keeping it cost-effective. The researchers conducted a literature review as well as agency and landowner surveys. They also acquired crash data, snow fence and blowing snow segment inventory data, and blowing snow removal expenditure data as well as performed benefit-cost analyses of three types of snow fences following Federal Highway Administration guides. The survey results suggested that standing corn rows (SCRs) and structural snow fences (SSFs) were the least intrusive options for landowners and living snow fences (LSFs) with trees were the most intrusive. Some concerns related to LSFs could be reduced by allowing landowners to play a role in the design and plant-selection process. The crash data indicated that no fatal and severe crashes occurred at snow fence segments, while several fatal and severe crashes occurred at blowing snow segments during 2012–2016. The results of the benefit-cost analyses showed that the benefit-cost ratios for LSFs and SSFs are comparable. However, LSFs are favorable over SSFs because little maintenance is needed after the plants are mature. Although SCRs have the highest benefit-cost ratio, the need to renew the agency-landowner agreement annually and the alternating of crops planted may limit their snow-control effectiveness and large-scale implementation. A tool was developed using MS Excel to facilitate the benefit-cost analysis of snow fences.

Design of Living Barriers to Reduce the Impacts of Snowdrifts on Illinois Freeways

Blowing snow accounts for a large part of Illinois Department of Transportation’s total winter maintenance expenditures. This project aims to develop recommendations on the design and placement of living snow fences (LSFs) to minimize snowdrift on Illinois highways. The research team examined historical IDOT data for resource expenditures, conducted a literature review and survey of northern agencies, developed and validated a numerical model, field tested selected LSFs, and used a model to assist LSF design. Field testing revealed that the proper snow fence setback distance should consider the local prevailing winter weather conditions, and snow fences within the right-of-way could still be beneficial to agencies. A series of numerical simulations of flow around porous fences were performed using Flow-3D, a computational fluid dynamics software. The results of the simulations of the validated model were employed to develop design guidelines for siting LSFs on flat terrain and for those with mild slopes (< 15° from horizontal). Guidance is provided for determining fence setback, wind characteristics, fence orientation, as well as fence height and porosity. Fences comprised of multiple rows are also addressed. For sites with embankments with steeper slopes, guidelines are provided that include a fence at the base and one or more fence on the embankment. The design procedure can use the available right-of-way at a site to determine the appropriate fence characteristics (e.g., height and porosity) to prevent snow deposition on the road. The procedure developed in this work provides an alternative that uses available setback to design the fence. This approach does not consider snow transport over an entire season and may be less effective in years with several large snowfall events, very large single events, or a sequence of small events with little snowmelt in between. However, this procedure is expected to be effective for more frequent snowfall events such as those that occurred over the field-monitoring period. Recommendations were made to facilitate the implementation of research results by IDOT. The recommendations include a proposed process flow for establishing LSFs for Illinois highways, LSF siting and design guidelines (along with a list of suitable plant species for LSFs), as well as other implementation considerations and identified research needs.

FAT tool: A decision support tool for disaster risk reduction in the Alpine Space

&lt;p&gt;The last decades have seen a higher attention payed to natural hazards due to the increasing losses and economic damages caused by them. Researchers, practitioners and local administrations studied the best way to mitigate and prevent them, using both structural and non-structural&amp;#160; defense techniques. Even though there are now several possible solutions to be used, it is not always easy for decision makers to choose the best option from both a technical and an economical point of view.&lt;/p&gt;&lt;p&gt;With the FAT tool we aimed at providing a useful mean for practitioners to help them choose between various protection options. The FAT tool is an online platform where the user, inserting a limited number of input data (e.g. slope profile, slope width, forest cover), is provided with an easily understandable output, that being a comparison of the costs and the benefits generated by different protection solutions.&lt;/p&gt;&lt;p&gt;The tool is built on an empirical, profile-based hazard model and deals with avalanches, rockfall and shallow landslides. The outputs of the hazard models are used to dimension and calculate the costs and benefits of several protection options and the damages avoided by those. The possible solutions considered are: ecosystem based solutions (e.g. protection forest), technical measures (e.g. snow fences, catching dams, rockfall nets), avoidance measures (e.g. road closure, building evacuation) and a combination of these. The most innovative part of the tool is the importance given to the role of the forest, and generally to the Eco-DRR solutions, on the hazard track, where a forest protection effect indicator is calculated to assess the effectiveness of a stand in mitigating the risk on the chosen profile. The outputs of the FAT tool, consisting in the index and the economic values of different alternative protection measures, can help the user identify the areas where the forests have the highest mitigation effect and choose where to allocate forest management resources.&lt;/p&gt;

Living snow fences for protection of roads: case study crest Čestobrodica

Snowdrifts caused by wind gusts reduce visibility on the road which endangers traffic safety, increases travel time and road maintenance costs. Based on previous experience and research it has been proven that living snow fence is an economical, ecological and efficient solution for protection of roads from snowdrifts. Living snow fences with their above-ground part, reduce the wind speed, act as a mechanical barrier for the snow and accumulate a certain amount of snow. This study presented use and efficiency of living snow fence in controlling snowdrifts on the road section Paraćin-Zaječar, locality – crest Čestobrodica. Analysis of environmental conditions, which are resented main endangering factor for snowdrifts, included the determination of indicators of possibility of snowdrifts: snowfall water equivalent (Swe), snow transport (Q) and ability of living snow fence to prevent snowdrifts: snow storage capacity of the fance (Qc). Snow storage capacity for living snow fence is analyzed for ten year period. Using equation for estimation of length of snowdrifts on downwind side of fance, a change in length of snowdrifts during the analyzed period are determin, and the efficiency of living snow fence in protection of the road from snowdrifts with increasing age.The results of this study represent a contribution to using living snow fence in solving the problem of roads protection from snowdrifts and increasing traffic safety during winter conditions.

The Effects of Predicted Soil Moisture and Temperature Increase on CO2 Exchange within a High Arctic Ecosystem

With 2014 being the warmest year on record and 10 of the warmest years occurring after 1997, it is essential to understand the effects of this warming on CO2 exchange. It was also discovered that much of this warming is focused in the Arctic regions, which are sensitive to changes in temperature (Cole & McCarthy, 2015). My research examines the effects of enhanced snowfall and soil temperature on the exchange of CO2 between the land and the atmosphere in a high arctic environment. The research is taking place at Cape Bounty Arctic Watershed Observatory (CBAWO) on Melville Island, Nunavut as part of the International Tundra Experiment (ITEX). The goal of ITEX is to better understand the effects of increased summer temperature and increased snowfall on arctic ecosystems. This is a full factorial experiment including treatments varying precipitation (and likely soil moisture), soil temperature, moisture and temperature together, and a control that is at ambient soil moisture and temperature. Snow fences are used to enhance precipitation, while open-topped transparent chambers are used to increase soil temperature. In a companion lab experiment, I look at the effects of different soil moisture levels and temperatures on soil CO2 production in a more controlled environment. Two temperatures, two moisture levels, and eight replicates of each will be established in sealed incubation chambers, and soils will be incubated for 33 days. Presently a significant relationship has been found between soil moisture and CO2 flux within the field experiment.

Investigating Safety Effectiveness of Wyoming Snow Fence Installations Along a Rural Mountainous Freeway

Drifting and blowing snow is a problematic and dangerous aspect of Interstate travel in the state of Wyoming. The control of snow and the maintenance of roadways is an essential and significant task for many state and local agencies. Many significant factors—such as vehicle control, surface conditions, and visibility—can be affected by hazardous winter weather. In areas such as the inspected 19-mi section of Interstate 80, snow fences have become a common and practical method of mitigating the problems caused by large quantities of snow near or on the traveled way. Wyoming deals with a high rate of adverse weather–related crashes during the winter season. Naive before–after analyses of snow fence installations have historically indicated a slight decrease in such crashes. In this study, the safety effectiveness of snow fence installations was investigated; more rigorous quantitative-based approaches were used and included a before–after analysis with empirical Bayes—in which Wyoming-specific safety performance functions were used—and odds ratio analyses. Crash modification factors were estimated for various crash types and severity levels. The results from this study indicate that the installation of snow fences contributes to a significant increase in the safety effectiveness of Interstate use during the winter. Specifically, it was found that during adverse weather conditions, snow fences decreased total crashes and fatal and injury crashes by about 25% and 62%, respectively.