Erosion Control Treatments Research Articles

Runoff sediment particle sizes associated with soil erosion in the Lake Tahoe Basin, USA

AbstractRunoff sediment from disturbed soils in the Lake Tahoe Basin has resulted in light scattering, accumulation of nutrients, and subsequent loss in lake clarity. Little quantified information about erosion rates and runoff particle‐size distributions (PSDs) exists for determining stream and lake loading associated with land management. Building on previous studies using rainfall simulation (RS) techniques for quantifying infiltration, runoff, and erosion rates, we determine the dependence and significance of runoff sediment PSDs and sediment yield (SY, or erodibility) on slope and compare these relationships between erosion control treatments (e.g., mulch covers, compost, or woodchip incorporation, plantings) with bare and undisturbed, or ‘native’ forest soils. We used simulated rainfall rates of 60–100 mm h−1 applied over replicated 0·64 m2 plots. Measured parameters included time to runoff (s), infiltration and runoff rates (mm h−1), SY (g mm−1 runoff), and average sediment concentration (SC, g L−1) as well as PSDs in runoff samples. In terms of significant relationships, granitic soils had larger particle sizes than volcanic soils in bulk soil and runoff samples. Consequently, runoff rates, SCs, and SYs were greater from bare volcanic as compared to that from bare granitic soils at similar slopes. Generally, runoff rates increased with increasing slope on bare soils, while infiltration rates decreased. Similarly, SY increased with slope for both soil types, though SYs from volcanic soils are three to four times larger than that from granitic soils. As SY increased, smaller particle sizes are observed in runoff for all soil conditions and particle sizes decreased with increasing slope. Copyright © 2008 John Wiley & Sons, Ltd.

Impact of land use and land cover changes on ecosystem services in Menglun, Xishuangbanna, Southwest China

Changing the landscape has serious environmental impacts affecting the ecosystem services, particularly in the tropics. In this paper, we report changes in ecosystem services in relation to land use and land cover over an 18-year period (1988--2006) in the Menglun Township, Xishuangbanna, Southwest China. We used Landsat TM/ETM and Quickbird data sets to estimate changes in ten land use and land cover categories, and generalized value coefficients to estimate changes in the ecosystem services provided by each land category. The results showed that over the 18-year period, the land use and land cover in the study area experienced significant changes. Rubber plantations increased from 12.10% of total land cover to 45.63%, while forested area and swidden field decreased from 48.73 and 13.14 to 27.57 and 0.46%, respectively. During this period, the estimated value of ecosystem services dropped by US $11.427 million (approximately 27.73%). Further analysis showed that there were significant changes in ecological functions such as nutrient cycling, erosion control, climate regulation and water treatment as well as recreation; the obvious increase in the ecological function is provision of raw material (natural rubber). Our findings conclude that an abrupt shift in land use from ecologically important tropical forests and traditionally managed swidden fields to large-scale rubber plantations result in a great loss of ecosystem services in this area. Further, the study suggests that provision of alternative economic opportunities would help in maintaining ecosystem services and for an appropriate compensation mechanisms need to be established based on rigorous valuation.

Yard Waste Compost as a Stormwater Protection Treatment for Construction Sites

Runoff water quality improvement from three yard waste compost erosion control treatments were compared with two conventional treatments and an untreated control on plots of 3:1 slope during two growing seasons, using natural events and simulated rainfall. Runoff volume, suspended solids, nutrients, biomass, turf shear strength, and turfgrass color scale were monitored. The most effective compost treatment, a 5-cm thick blown compost blanket, produced 12.7 times less runoff and 9.8 times less sediment load than a straw mat and silt fence treatment. The compost treatments generated eight times more biomass than the straw mat treatments. Root development was significantly better on the compost treatments based on turf shear strength measurements. Tilled-in compost was not as effective as a compost blanket at reducing sediment loss, particularly before the establishment of grass on the plot. The cost of compost treatments was similar to that of straw mat with silt fence treatments.

Optimization strategies for sediment reduction practices on roads in steep, forested terrain

AbstractMany forested steeplands in the western United States display a legacy of disturbances due to timber harvest, mining or wildfires, for example. Such disturbances have caused accelerated hillslope erosion, leading to increased sedimentation in fish‐bearing streams. Several restoration techniques have been implemented to address these problems in mountain catchments, many of which involve the removal of abandoned roads and re‐establishing drainage networks across road prisms. With limited restoration funds to be applied across large catchments, land managers are faced with deciding which areas and problems should be treated first, and by which technique, in order to design the most effective and cost‐effective sediment reduction strategy. Currently most restoration is conducted on a site‐specific scale according to uniform treatment policies. To create catchment‐scale policies for restoration, we developed two optimization models – dynamic programming and genetic algorithms – to determine the most cost‐effective treatment level for roads and stream crossings in a pilot study basin with approximately 700 road segments and crossings. These models considered the trade‐offs between the cost and effectiveness of different restoration strategies to minimize the predicted erosion from all forest roads within a catchment, while meeting a specified budget constraint. The optimal sediment reduction strategies developed by these models performed much better than two strategies of uniform erosion control which are commonly applied to road erosion problems by land managers, with sediment savings increased by an additional 48 to 80 per cent. These optimization models can be used to formulate the most cost‐effective restoration policy for sediment reduction on a catchment scale. Thus, cost savings can be applied to further restoration work within the catchment. Nevertheless, the models are based on erosion rates measured on past restoration sites, and need to be updated as additional monitoring studies evaluate long‐term basin response to erosion control treatments. Copyright © 2006 John Wiley & Sons, Ltd.

Streamflow and suspended sediment yield following the 2000 Bobcat fire, Colorado

Postfire runoff and erosion are a concern, and more data are needed on the effects of wildfire at the watershed-scale, especially in the Colorado Front Range. The goal of this study was to characterize and compare the streamflow and suspended sediment yield response of two watersheds (Bobcat Gulch and Jug Gulch) after the 2000 Bobcat fire. Bobcat Gulch had several erosion control treatments applied after the fire, including aerial seeding, contour log felling, mulching, and straw wattles. Jug Gulch was partially seeded. Study objectives were to: (1) measure precipitation, streamflow, and sediment yields; (2) assess the effect of rainfall intensity on peak discharges, storm runoff, and sediment yields; (3) evaluate short-term hydrologic recovery. Two months after the fire, a storm with a maximum 30 min rainfall intensity I30 of 42 mm h−1 generated a peak discharge of 3900 l s−1 km−2 in Bobcat Gulch. The same storm produced less than 5 l s−1 km−2 in Jug Gulch, due to less rainfall and the low watershed response. In the second summer, storms with, I30 of 23 mm h−1 and 32 mm h−1 generated peak discharges of 1100 l s−1 km−2 and 1700 l s−1 km−2 in the treated and untreated watersheds respectively. Maximum water yield efficiencies were 10% and 17% respectively, but 18 of the 23 storms returned ≤2% of the rainfall as runoff, effectively obscuring interpretation of the erosion control treatments. I30 explained 86% of the variability in peak discharges, 74% of the variability in storm runoff, and >80% of the variability in sediment yields. Maximum single-storm sediment yields in the second summer were 370 kg ha−1 in the treated watershed and 950 kg ha−1 in the untreated watershed. Copyright © 2005 John Wiley & Sons, Ltd.

Simulated rainfall evaluation of revegetation/mulch erosion control in the Lake Tahoe basin—3: soil treatment effects

AbstractRevegetation, or other erosion control treatments of disturbed soil slopes in forested areas and along highways of the Lake Tahoe basin are directed at reduction of sediment loading to waterways reaching the lake. However, following treatment, little vegetation monitoring, or hydrologic evaluation has been conducted either to determine if the various treatments are successful or to assess the duration of erosion control anticipated in the field. Here, we build upon results from use of the portable rainfall simulator (RS) described in the first two papers of this series to evaluate cover and revegetation treatment effects on runoff rates and sediment concentrations and yields from disturbed granitic and volcanic soils in the basin. The effects of slope on rainfall runoff, infiltration and erosion rates were determined at several revegetated road cut and ski run sites. Rainfall simulation (∼60 mm h−1, approximating a 100‐year, 15‐minute storm) had a mean drop size of ∼2·1 mm and approximately 70 per cent of ‘natural’ rainfall kinetic energy. Measurements of: time to runoff; infiltration; runoff amount; sediment yield; and average sediment concentration were obtained. Runoff sediment concentrations and yields from sparsely covered volcanic and bare granitic soils can be correlated to slope. Sediment concentrations and yields from nearly bare volcanic soils exceeded those from granitic soils by an order of magnitude across slopes ranging from 30–70 per cent. Revegetation, or application of pine‐needle mulch covers to both soil types dramatically decreased sediment concentrations and yields. Incorporation of woodchips or soil rehabilitation that includes tillage, use of amendments (biosol, compost) and mulch covers together with plant seeding resulted in little or no runoff or sediment yield from both soils. Repeated measurements of sediment concentrations and yields in the subsequent two years following woodchip or soil rehabilitation treatments continued to result in little or no runoff. Revegetation treatments involving only use of grasses to cover the soils were largely ineffective due to sparse sustainable coverage (< 35 per cent) and inadequate infiltration rates. Copyright © 2005 John Wiley & Sons, Ltd.

Improved Erosion Control Selection for Steep Slopes with the USDA Forest Service Erosion Control Selection Guide

Low-volume forest roads are a significant source of erosion and can be challenging and expensive to control because of the steep (greater than 50% slope gradient) slopes. Most erosion control documents lack guidance on treatment selection, emphasize temporary erosion control, and do not adequately address steep slopes. To address the deficiency, the U.S. Department of Agriculture Forest Service San Dimas Technology and Development Center created the USDA Forest Service Erosion Control Selection Guide. The primary focus of the guide is technical information to assist long-term erosion control treatment selection on steep slopes, particularly road cut and fill slopes. This guide is a synthesis of information encompassing erosion control fundamentals, erosion and sediment yield prediction models, treatment parameters, erosion control treatments, selection tips, installation tips, and additional resources. Treatments include grading, seeding, mulch, soil amendments, rolled erosion control products, soil bioengineering, and biotechnical stabilization. Significant advantages of the guide include general treatment selection guidance, inclusion of permanent treatment methods, and consideration of steep slopes. The guide is limited because of the complex nature of erosion; it does not address nontechnical issues, and it may need updating as new information becomes available. Despite these limitations, the guide is a valuable new tool for reducing erosion and sediment yield on steep slopes of low-volume roads.

PERFORMANCE OF EROSION CONTROL PRODUCTS ON A HIGHWAY EMBANKMENT

Unprotected soil at construction sites often results in large rates of erosion. Five different erosion control treatments were tested on the slopes of a highway sedimentation basin to determine their impact on vegetative growth, runoff, and erosion. The treatments were a bare (no treatment) condition, a disk–anchored straw mulch, a wood–fiber blanket, a straw/coconut blanket, and a bonded–fiber matrix product (hydraulically applied). A minimum of three replicates was used for each treatment. Straw mulch was selected as the standard treatment for statistical analyses. The site was planted with native prairie seeds, and the establishment of vegetation was monitored over the growing season. Above–ground biomasses for the bare and straw–mulch treatments were statistically greater than those of the bonded–fiber matrix treatment. Statistically significant differences in above–ground biomass for the other treatments were undetected at the 10% level. Weedy grasses and forbs were the dominant plant species. Runoff and erosion data were collected using a rotating–boom rainfall simulator for spring and fall sets of runs corresponding to little and good vegetative growth, respectively. Runoff depths were generally larger from straw–mulch and bare plots. There were no statistically significant differences in relative runoff depth between the blankets and the bonded–fiber matrix product. Under conditions with little vegetation, erosion from the straw–mulch plots was roughly one–tenth of that from the bare soil plots; erosion from the blanket and bonded–fiber matrix plots was roughly one–tenth of that from the straw–mulch plots. There were no statistically significant differences in relative sediment yield between the blankets and the bonded–fiber matrix. Erosion from bare and straw–mulch treatments was greatly reduced by vegetative growth that occurred between the spring and fall runs.

An assessment of land use and other factors affecting sediment loads in the Rio Puerco watershed, New Mexico

Abstract Rapid channel erosion in the Rio Puerco watershed of northwest New Mexico has been attributed to land use, climate changes, and internal channel adjustments. The objectives of this study were to assess (1) the impacts of land uses on sediment load, (2) the quantitative relationships between land use and sediment load, and (3) the effectiveness of different erosion control methods. The impacts of land uses on sediment load were assessed via hypotheses that, holding other erosion-related variables constant, sediment load correlates positively with grazing intensity and with density of unpaved roads, and correlates negatively with the number of erosion control treatments. We calculated the average annual sediment load for 17 subbasins of 0.67–17.97 km 2 by comparing sediment accumulation at two points in time (mid-1960s and 1999) behind intact sediment retention structures. We assessed land use via grazing records and measurements of unpaved roads generated from aerial photographs. Soil characteristics, vegetation, and physical factors were quantified for each subbasin. Using 18 variables for each subbasin, we employed Mallow's C p as a selection criterion. We used six statistical models, including multiple regression and principal components analysis, to determine inherent mathematical relationships between significant independent variables and sediment load. The results indicate that sediment load does not correlate with grazing intensity except in small, relatively low-relief basins with fewer bedrock exposures. However, this interpretation may be compromised by the low quality of data available to quantify grazing. Sediment load is highly sensitive to the presence of unpaved roads, which serve as high gradient, channelized conduits of water and sediment during storms. Sediment load does not correlate with erosion control except in the subset of small, relatively low-relief subbasins that also proved sensitive to grazing intensity. Overall, the statistical analyses suggest that the impact of land uses on sediment load can be assessed using the data available although physical factors appear more significant than land use in producing high sediment loads in the Rio Puerco subbasins. Historical erosion control techniques, as implemented in the Rio Puerco watershed, prove largely ineffective against accelerated sediment loads because they have not been appropriately implemented or maintained.

Sediment production from granitic cutslopes on forest roads in Idaho, USA

A series of 75 non-bordered plots was used to measure surface erosion on granitic road cuts on forest roads in the mountains of Idaho. Erosion data were collected for four years following road construction. Erosion rates for the first winter period after construction averaged about five times greater than the average of erosion rates for subsequent seasons. Both mass and surface erosion processes were observed on road cuts with mass erosion particularly important during the first season after construction. Regression analysis showed slope gradient, slope aspect, ground cover density and snow-free period rainfall erosivity had statistically significant effects on erosion. Slope gradient was by far the most influential site factor affecting erosion but slope length had no affect. Three erosion control treatments – dry seeding, hydroseeding plus mulch, and terracing with hydroseeding plus mulch – were evaluated. Two treatments – dry seeding and hydroseeding plus mulch –caused statistically significant reductions in erosion. Dry seeding was the most cost-effective treatment on sites with deep alluvial soil. Elsewhere, hydromulching was the most cost-effective treatment. Further testing is needed to evaluate the effectiveness of erosion control treatments during the first period after construction. We were unable to discriminate between erosion rates on the moderately to highly weathered granitic rock included in this study. A discussion of the application of the study results is presented. Copyright © 2001 John Wiley & Sons, Ltd.

Erosion and sediment delivery following removal of forest roads

Erosion control treatments were applied to abandoned logging roads in California, with the goal of reducing road-related sediment input to streams and restoring natural hydrologic patterns on the landscape. Treatment of stream crossings involved excavating culverts and associated road fill and reshaping streambanks. A variety of techniques were applied to road benches, which included decompacting the road surface, placing unstable road fill in more stable locations, and re-establishing natural surface drainage patterns. Following treatment and a 12-year recurrence-interval storm, some road reaches and excavated stream crossings showed evidence of mass movement failures, gullying, bank erosion and channel incision. Post-treatment erosion from excavated stream crossings was related to two variables: a surrogate for stream power (drainage area × channel gradient) and the volume of fill excavated from the channel. Post-treatment erosion on road reaches was related to four explanatory variables: method of treatment, hillslope position (upper, mid-slope or lower), date of treatment, and an interaction term (hillslope position × method of treatment). Sediment delivery from treated roads in upper, middle and lower hillslope positions was 10, 135 and 550 m3 of sediment per kilometre of treated roads, respectively. In contrast, inventories of almost 500 km of forest roads in adjacent catchments indicate that untreated roads produced 1500 to 4700 m3 of sediment per kilometre of road length. Erosion from 300 km of treated roads contributed less than 2 per cent of the total sediment load of Redwood Creek during the period 1978 to 1998. Although road removal treatments do not completely eliminate erosion associated with forest roads, they do substantially reduce sediment yields from abandoned logging roads. Published in 2001 by John Wiley & Sons, Ltd.

Erosion Control Techniques on Forest Road Cutslopes and Fillslopes in North Alabama

Road cutslopes and fillslopes account for approximately 50 percent of the total road disturbance area on steep terrain and contribute as much as 60 percent of sediment from forest roads. The significance of erosion control techniques on these vulnerable components of the road prism has become evident in recent years. A study to gain a better understanding of erosion control techniques on road cutslopes and fillslopes is detailed. Sediment and runoff yield from three erosion control treatments and a control were investigated on west-facing 2:1 and 1.5:1 cutslopes and fillslopes, respectively, on a newly constructed road during a 30-month study. The treatments evaluated were a wood excelsior erosion mat, native species grass, and exotic species grass. Factors detected to significantly affect sediment yield from road sideslopes were treatment, time, and treatment-time interaction based on analysis of variance. Significant reductions in sediment yield and runoff were found on all treatments on both the cutslope and fillslope. The erosion mat most effectively controlled erosion losses on both slopes for all study periods.

The influence of rolled erosion control systems on soil moisture content and biomass production: part II. A greenhouse experiment

A controlled greenhouse experiment conducted under high shortwave radiation flux explored the relationship between seven rolled erosion control systems (RECS) and a bare control treatment on soil moisture content (SMC), ryegrass yield, and ryegrass nutrient assimilation. All RECS conserved more moisture in the soil profile than the bare treatment. But, differences between RECS occurred. Geojute was the poorest performer, with mean SMC values commonly 18–30 per cent lower than the other RECS studied; and under drought-induced conditions SMC values were up 22–45 per cent lower than the other systems. Ryegrass yields varied with surface cover, with statistical testing indicating that the bare, Geojute® and P300® treatments were not significantly different. However, the remaining RECS (Futerra®, BioD-Mat™ 70®, C125®, SC150BN® and Curlex® I) had significantly higher ryegrass yields, with Curlex I® being 25 per cent higher than its nearest competitor, SC150BN®. Ryegrass nutrient concentrations of nitrogen and sulfur were generally similar between rolled erosion control treatments, and no measured macronutrient was considered to be deficient. This information coupled with correlation analysis indicated that the soil thermal regime was the most important limiting factor on biomass production. Additionally, of all variables examined by stepwise regression (microclimate and cardinal properties of RECS) only surface albedo (shortwave reflectivity) was significantly related with ryegrass yield. Closer attention needs to be given to the three-dimensionality of rolled erosion control fibers, and their radiative properties if designers are interested in maximizing biomass production from slopes covered by RECS in subtropical/tropical and semiarid environments. © 1998 John Wiley & Sons, Ltd.

Erosion And Runoff Control Using Bulldozer Imprints On Surface-Mine Spoil

ABSTRACT Bare surface-mined areas are susceptible to severe erosion and erosion-control practices are required, especially when vegetative cover is being established. A study using simulated rainfall was conducted to evaluate the effects of three erosion-control treatments which manipulate microtopography and can be easily applied with a track-type bulldozer. Treatments were evaluated in which spoil was backbladed, and track cleat marks were imprinted in spoil parallel and perpendicular to the slope (corresponding to bulldozer movement perpendicular and parallel to the slope direction, respectively). Tracks imprinted along the contour of the slope were effective in controlling erosion during a series of three severe storms, but runoff control diminished as the storms were applied. Backbladed plots yielded the highest runoff and soil losses. Operating bulldozers to imprint track marks along the contour on long slopes (bulldozer movement up and down the slope) should be done with a supporting practice, such as diversions.

A Review of Mulches to Control Wind Erosion

ABSTRACT THE need to increase food production and improve the quality of our environment has prompted a search for materials to control wind and water erosion. This paper is a review of research and development as-sociated with application, methods, and amounts of mulch typescrop residues, chemical soil stabilizers, and feedlot wastes (manure)required to control wind erosion. An effective wind erosion control treatment is one that can resist a 38.0 m/s wind as measured at 15.2 m. Any crop residue, either grown in place or hauled in and spread, can control wind erosion. Hauled-in residues must be spread and anchored to the soil surface by a packer or an anchoring agent, i.e., cutback asphalt or asphalt emulsion. Depending on residue type, minimum amounts needed to control wind erosion are 4.5 to 11 t/ha. Chemical soil stabilizers, i.e., asphalt, polyvinyl alcohol, styrene-butadiene latex emulsions, and resins-in-water emulsions control wind erosion effectively if properly diluted and applied to cover the total soil surface at volumes of at least 3785 L/ha. Wet feedlot manure applied to a highly-erodible sand con-trolled erosion with 31.8 t/ha surface-applied or 52.3 t/ha tilled-in with a tandem disk.

Soil Changes Caused by Erosion Control Treatments on a Salt Desert Area

AbstractSoil samples taken in the environs of gully plugs and contour furrows installed in shale‐derived saline‐sodic soils showed that the physical and chemical characteristics differed from the control profile. Physical measurements of moisture holding capacity, bulk density, and infiltration, varied because of fine clay deposition in the catchment basins of these structures and because of the mechanical disturbance of the shale during gully plug and furrow construction.Electrical conductivity and sodium measurements differed from the normal profile due to leaching since construction. The movement of salts was related to the rainfall received rather than to the season. These edaphic changes would have a profound effect on the establishment, development, and growth of introduced species seeded on the treatments.

Seedling Survival on Erosion Control Treatments in a Salt Desert Area

Counts of seeded crested wheatgrass (Agropyron cristatum) and volunteer species were made on gully plugs and contour furrows in the spring to determine emergence and in the summer to determine survival rates. Soil surface moisture was measured 2 and 7 days following summer rain storms. Many seedlings emerged in the spring in response to winter and early spring precipitation. This moisture was quickly depleted. The retention of moisture from summer storms determined the seedling survival pattern around the structures. Drowning was apparent in gully plug bottoms, while slopes of the structures retained little water during the storms. The combination of irregular rainfalls, high evaporation rates, and poor soil infiltration rates reduced the effectiveness of summer rains. Only at the high water line of the gully plug retention dam and at the bottom of the furrows was there enough soil moisture to benefit seedlings.