Abstract Airborne dust suppression is of critical importance to military operations conducted in desert environments. Airborne dust is commonly generated in the desert by surface and near-surface operations during operational, testing, and training missions. Currently, there is no standardized procedure for testing dust suppressants, and the U.S. military lacks a specific test operations procedure (TOP) designed to provide realistic testing of the performance and durability of commercial products sold for dust abatement. The primary purpose of this study is to provide recommendations for the future development of a TOP for testing dust suppressants applied to desert soils. Recommendations were developed from the evaluation of a polyvinyl-based synthetic polymer as a dust suppressant, which was tested at four test intervals over a 19–week period in the late spring and summer of 2008 at the U.S. Army Yuma Proving Ground. The dust suppressant was applied at three separate test sites having different surface characteristics and soil properties ranging from loose, sandy gravel to gravelly sand, alluvial-fan soils to soft, sandy-silt, alluvial-plain soils. Each test site was subjected to a variety of traffic impact types consisting of an increasing number of cumulative passes by different vehicle types—including a low-flying helicopter, a light-weight armored tracked vehicle, and heavy-, medium-, and lightweight wheeled vehicles, plus pedestrian foot traffic. In addition to the sites of traffic impact, three types of control plots were concurrently tested to act as reference sites, as well as to evaluate the longevity of the suppressant, which included: disturbed and static (undisturbed) baseline plots and a static benchline plot. Surface soil and dust-suppressant physical properties were measured following each traffic impact in the form of shear strength and bearing capacity, plus dust-emission flux as measured by a Portable In Situ Wind ERosion Laboratory (PI-SWERL). Results from this study show that dust-emission flux and surface-strength measurements from a layout of control and traffic impact test plots provide a quantifiable and repeatable approach in measuring the efficacy of a dust suppressant for a TOP used by the U.S. Army.

Abstract Dryland channel networks share many similarities with channel networks in more humid regions, but they are also unique in having: extreme temporal and spatial variability in rainfall, runoff, and both hillslope and channel processes; poor integration between tributary and main channels; dominantly ephemeral or intermittent flow; and lack of equilibrium between process and form. Floods are likely to be particularly important in dryland channels, and riparian vegetation exerts a strong influence on channel processes and form. Land managers working in dryland channel networks particularly need to answer the following questions: What is stable? What is the role of disturbance? How do ecosystems depend on physical form and process? This paper explores methods for determining thresholds and resiliency within a channel network and suggests metrics that can be used to assess the condition of a channel segment or entire drainage network relative to management goals. The management metrics focus on flow regime, sediment supply, bed grain size, bedform configuration, width/depth ratio, bed gradient, channel planform, and extent and type of riparian vegetation. For each of these metrics, geological, historical, and systematic records can be used to define the natural range of variability for a particular channel form in the absence of direct land-use impacts. The range of variability present under land use such as military training activities can then be compared to the natural range to assess whether these activities are negatively affecting the dryland channel network. The Yuma Wash drainage in the Yuma Proving Ground, Arizona, is used as a case study.