Sediment generation from forest roads: bed and eroded sediment size distributions, and runoff management strategies

Soil Research ◽  
1999 ◽  
Vol 37 (5) ◽  
pp. 947 ◽  
Author(s):  
R. D. Connolly ◽  
A. Costantini ◽  
R. J. Loch ◽  
R. Garthe
Keyword(s):  
Overland Flow ◽  
Fine Particles ◽  
Management Strategies ◽  
Size Distributions ◽  
Wet Season ◽  
Support Tool ◽  
Forest Road ◽  
Sediment Size ◽  
Overland Flows ◽  
Road Surfaces

A rainfall simulator and overland flow study was conducted to determine in situ and eroded sediment size distributions for a range of forest road surfaces at 2 important commercial plantation centres in subtropical south-east Queensland, Australia; and parameters necessary for running the CREAMS model to assess erosion and sediment transport from road/table drain systems. Results revealed very low concentrations of fine particles in the surface of gravel roads, and somewhat higher proportions in ungravelled (dirt) road surfaces. However, there was considerable enrichment of fine particles in sediment eroded under simulated rain, with concentrations of particles <0 . 02 mm in diameter being up to 8 g/L. Table drains were generally resistant to scour by overland flows, with the only exception being a drain bordering a newly gravelled road. This drain was bare of vegetation and contained significant quantities of loose gravel from which the fine component was easily eroded. It demonstrated the need to construct both roads and table drains at the end of the wet season when consolidation and re-vegetation can occur under lighter rains during the dry season. CREAMS model runs for a ‘standard’ road and drain configuration predicted considerable enrichment of fine particles in sediment from all road surfaces. The major factor controlling predicted concentrations of fine particles was the rate of erosion from the road surface, with gravelled surfaces showing considerably less erosion than ungravelled surfaces. Because road surfaces will be significant sources of fine sediment during erosive rains, a second part of this study was designed to model whether hillslopes could be used to infiltrate runoff, thereby controlling sediment movement. For the modelled hillslopes—typical of those used to support commercial forest plantations in south-east Queensland—design runoffs from forest road turn-out drains could be infiltrated. It is suggested that forest managers use hillslope infiltration as the primary tool for managing flows and sediments from road turn-out drains, and that vegetative filter strips be used only as a secondary support tool.

Field rainfall simulator studies on two clay soils of the Darling Downs, Queensland. II. Aggregate Breakdpwn, sediment properties and soil erodibility

Soil Research ◽  
1983 ◽  
Vol 21 (1) ◽  
pp. 47 ◽  
Author(s):  
RJ Loch ◽  
TE Donnollan
Keyword(s):  
Overland Flow ◽  
Clay Soils ◽  
Bed Load ◽  
Flowing Water ◽  
Size Distributions ◽  
Runoff Water ◽  
Sediment Size ◽  
Soil Sediment ◽  
The Difference ◽  
Load Sediment

Size distributions of the solids in runoff water were measured for two clay soils subjected to simulated rain under a range of plot lengths and two tillage orientations. Selective transport did not appear to have affected the sediment size distributions. Therefore, these could be used as a measure of soil structure and aggregate breakdown by rainfall and runoff. There was little dispersed clay, most of the sediment remaining aggregated. For each soil, sediment size distributions were bimodal, peaks in sediment size being related to orders of aggregation in each soil. Concentrations of dispersed clay provide evidence that stresses on aggregates moved by rain impact on flowing water were greater than on those moved in rills by flowing water alone. Consistent with this, sediment size distributions showed much less breakdown to sizes <0.125 mm in rills. Suspended load (sediment < 20 �m) showed little temporal fluctuation, and little or no decrease with time, suggesting that for these soils, aggregate disruption by raindrops and overland flow provides a continuous source of suspendable material. Bed-load was more variable and saltating and contact load appeared to be complementary to some extent. Large differences between the two soils in measured sediment concentrations could not be explained by slight differences in sediment size. However, large differences between the soils in the water content and density of saturated aggregates were found. Transport equations for bed-load sediment suggest that the measured difference in aggregate density is sufficient to explain the difference between the soils in rates of sediment transport.

Rill erosion of a self-mulching black earth. I. Effects of tillage

Soil Research ◽  
1989 ◽  
Vol 27 (3) ◽  
pp. 525 ◽  
Author(s):  
RJ Loch ◽  
TE Donnollan
Keyword(s):  
Overland Flow ◽  
Aggregate Size ◽  
Size Distributions ◽  
Silt Loam ◽  
Rill Erosion ◽  
Tillage Practices ◽  
Sediment Size ◽  
Stubble Retention ◽  
Silt Loam Soil ◽  
Loam Soil

The effects of three tillage treatments-rough-, fine- and zero-tilled-on rill erosion of a bare, self-mulching black earth were tested to determine whether tillage practices could reduce susceptibility of such soils to entrainment and transport by overland flow. In contrast to reported results for a silt loam soil, rill erosion was greatest for zero-tilled soil, and similar for the two tilled treatments. Sediment size distributions were independent of initial dry aggregate size distributions. It seems that, for self-mulching soils, stubble retention is the only method available to increase resistance to erosion by overland flow.

Manager-based valuations of alternative fire management regimes on Cape York Peninsula, Australia

2008 ◽  
Vol 17 (5) ◽  
pp. 660 ◽  
Author(s):  
Adam G. Drucker ◽  
Stephen T. Garnett ◽  
Marty K. Luckert ◽  
Gabriel M. Crowley ◽  
Niilo Gobius
Keyword(s):  
Decision Support ◽  
Fire Management ◽  
Climatic Variability ◽  
Management Strategies ◽  
Decision Support Tool ◽  
Wet Season ◽  
Gross Margin ◽  
Support Tool ◽  
Management Regimes ◽  
Cape York

Decisions about fire management on pastoral properties are often made with little empirical knowledge. Proper accounting of the interactions between land, pasture, trees and livestock within the context of climatic variability and market conditions is required in order to assess financial implications of alternative fire management regimes. The present paper aims to facilitate such accounting through the development of a manager-driven decision-support tool. This approach is needed to account for variable property conditions and to provide direction towards considering optimal practices among a vast array of potential activities. The tool is an interactive model, developed for a hypothetical property, which analyses the costs and benefits of a baseline (no fires) against a historically based probability of wildfire overlaid by four alternative fire management regimes, representing cumulatively increasing levels of fire management intensity. These are: Regime 1, no action taken to prevent or stop wildfires; Regime 2, fire suppression (reactive fighting of wildfire); Regime 3, Regime 2 plus prevention (early dry-season burning); and Regime 4, Regime 3 combined with storm-burning (burning soon after the first wet-season storm). The model, which shows that fire and fire management have significant influences on the gross margin of Cape York Peninsula cattle properties, can be used as a decision-support tool in developing fire management strategies for individual properties. Specific fire management recommendations follow, together with the identification of potential areas of future work needed to facilitate use of the tool by clients.

A Decision Support Tool for Wastewater Catchment Management

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
S.E. Walters ◽  
D. Savic ◽  
R.J. Hocking
Keyword(s):  
Decision Support ◽  
Asset Management ◽  
Capital Investment ◽  
Management Strategies ◽  
Sewage Treatment ◽  
Decision Support Tool ◽  
Catchment Management ◽  
Clean Water ◽  
Support Tool ◽  
South West

The water industry over the years has primarily focussed on upgrading and investing in clean water provision. However, as research into the science and management of clean water services has progressed rapidly, wastewater provision and services has been slower. Focus, though, is now shifting within Industry and Research into wastewater services. The water regulator, Ofwat, for England and Wales demands the Sewerage Undertakers demonstrate efficient management of wastewater systems in order to obtain funding for Capital Investment projects. South West Water, a Water Service Provider and Sewerage Undertaker located in the South West of England, identified a need gap in their asset management strategies for wastewater catchments. This paper will introduce the production of a Decision Support Tool, DST, to help SWW proactively manage their Wastewater Catchments, examining Sewage Treatment Works, Pumping Stations and Networks. The paper will discuss some concepts within the DST, its production, testing and a brief case study. The DST provides a framework for prioritising catchments to optimise investment choices and actions. The Tool ranks catchments utilising Compromise Programming, CP, as well as AHP Pair-wise comparisons for preference weights. The DST incorporates Asset models, a Whole life Costing Module, as well as a Decay and Intervention Module.

scholarly journals Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis

2021 ◽  
Author(s):  
Weiqi Xu ◽  
Chun Chen ◽  
Yanmei Qiu ◽  
Conghui Xie ◽  
Yunle Chen ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Fine Particles ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Size Distributions ◽  
The North ◽  
The Impact

Organic aerosol (OA), a large fraction of fine particles, has a large impact on climate radiative forcing and human health, and the impact depends strongly on size distributions. Here we...

scholarly journals Role of Runoff–Infiltration Partitioning and Resolved Overland Flow on Land–Atmosphere Feedbacks: A Case Study with the WRF-Hydro Coupled Modeling System for West Africa

2016 ◽  
Vol 17 (5) ◽  
pp. 1489-1516 ◽  
Author(s):  
Joel Arnault ◽  
Sven Wagner ◽  
Thomas Rummler ◽  
Benjamin Fersch ◽  
Jan Bliefernicht ◽  
...  
Keyword(s):  
West Africa ◽  
Overland Flow ◽  
River Flow ◽  
Efficiency Coefficient ◽  
Wet Season ◽  
Coupled Modeling ◽  
Study Region ◽  
Outer Domain ◽  
Terrestrial Water

Abstract The analysis of land–atmosphere feedbacks requires detailed representation of land processes in atmospheric models. The focus here is on runoff–infiltration partitioning and resolved overland flow. In the standard version of WRF, runoff–infiltration partitioning is described as a purely vertical process. In WRF-Hydro, runoff is enhanced with lateral water flows. The study region is the Sissili catchment (12 800 km2) in West Africa, and the study period is from March 2003 to February 2004. The WRF setup here includes an outer and inner domain at 10- and 2-km resolution covering the West Africa and Sissili regions, respectively. In this WRF-Hydro setup, the inner domain is coupled with a subgrid at 500-m resolution to compute overland and river flow. Model results are compared with TRMM precipitation, model tree ensemble (MTE) evapotranspiration, Climate Change Initiative (CCI) soil moisture, CRU temperature, and streamflow observation. The role of runoff–infiltration partitioning and resolved overland flow on land–atmosphere feedbacks is addressed with a sensitivity analysis of WRF results to the runoff–infiltration partitioning parameter and a comparison between WRF and WRF-Hydro results, respectively. In the outer domain, precipitation is sensitive to runoff–infiltration partitioning at the scale of the Sissili area (~100 × 100 km2), but not of area A (500 × 2500 km2). In the inner domain, where precipitation patterns are mainly prescribed by lateral boundary conditions, sensitivity is small, but additionally resolved overland flow here clearly increases infiltration and evapotranspiration at the beginning of the wet season when soils are still dry. The WRF-Hydro setup presented here shows potential for joint atmospheric and terrestrial water balance studies and reproduces observed daily discharge with a Nash–Sutcliffe model efficiency coefficient of 0.43.

Geographic Information System for Pigweed Distribution in the US Southeast

2018 ◽  
Vol 32 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Reginald S. Fletcher ◽  
Krishna N. Reddy
Keyword(s):  
United States ◽  
Open Source ◽  
Open Source Software ◽  
Precision Agriculture ◽  
Weed Management ◽  
Southeastern United States ◽  
Management Strategies ◽  
Geographic Information ◽  
County Level ◽  
Support Tool

AbstractIn the southeastern United States, Amaranthus, or pigweed species, have become troublesome weeds in agricultural systems. To implement management strategies for the control of these species, agriculturalists need information on areas affected by pigweeds. Geographic information systems (GIS) afford users the ability to evaluate agricultural issues at local, county, state, national, and global levels. Also, they allow users to combine different layers of geographic information to help them develop strategic plans to solve problems. Furthermore, there is a growing interest in testing free and open-source GIS software for weed surveys. In this study, the free and open-source software QGIS was used to develop a geographic information database showing the distribution of pigweeds at the county level in the southeastern United States. The maps focused on the following pigweeds: Palmer amaranth, redroot pigweed, and tall waterhemp. Cultivated areas and glyphosate-resistant (GR) pigweed data were added to the GIS database. Database queries were used to demonstrate applications of the GIS for precision agriculture applications at the county level, such as tallying the number of counties affected by the pigweeds, identifying counties reporting GR pigweed, and identifying cultivated areas located in counties with GR pigweeds. This research demonstrated that free and open-source software such as QGIS has strong potential as a decision support tool, with implications for precision weed management at the county scale.

scholarly journals Properties of recycled ceramic aggregates specified in WT-1 2014 Aggregates - Technical Requirements

2018 ◽  
Vol 49 ◽  
pp. 00001 ◽  
Author(s):  
Wojciech Andrzejuk ◽  
Mateusz Sałuch ◽  
Bartosz Zegardło ◽  
Elżbieta Szczygielska ◽  
Wioletta Żukiewicz-Sobczak ◽  
...  
Keyword(s):  
Fine Particles ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Asphalt Mixes ◽  
Technical Requirements ◽  
Fine Aggregates ◽  
Sanitary Ceramic ◽  
Road Surfaces ◽  
Methylene Blue Test ◽  
A Company

The article presents the results of research on primary recycling properties of ceramic aggregates conducted following the procedures outlined in WT-1 2014 Aggregates - Technical Requirements. The material for the tests was obtained from a company producing sanitary ceramic products. Damaged ceramic products, coming from the factory waste heaps, were transported to the laboratory and crushed. This enabled producing aggregate that was later subjected to tests carried out on the aggregates commonly used in the production of mineral-asphalt mixes applied in making road surfaces. The factors that were examined include the following: the flow rate of fine aggregates (angularity of fine aggregate), fine particles content - methylene blue test, light-weight impurities content, frost resistance, bulk density of grains as well as water absorption determined by pycnometric method. The test results showed that the properties of the recycled aggregates are similar to those included in traditional aggregates used for the production of mineral-asphalt mixes. On the basis of the conducted analyses, the waste ceramic aggregate was recommended for use.

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