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Accelerated soil erosion and the sedimentation caused by it pose serious problems for the construction industry and state and local agencies. Runoff from construction sites has high sediment loads which may contain various pollutants, including oil, chemicals, and soil wastes. Natural erosion in ditches and along roadways may result in sedimentation that may result in costly damage to water and land. Drainage channels, culverts, and storm sewers may be filled and plugged by sediment, resulting in frequent and costly maintenance. This report addresses those problems and outlines methods for controlling erosion both during and after construction. Structural and vegetative practices for reducing sedimentation are given, and turf establishment techniques for native grasses and wildflowers are discussed. Information regarding the National Pollution Discharge Elimination System (NPDES) Storm Water Permit Requirements is also given.

This report presents the results of a two-year field study on the performance of erosion control products under natural and artificial rainfall conditions. Vegetation, runoff, and erosion data were collected at a newly constructed roadway. Runoff and erosion data were gathered using natural rainfall events and using a rainulator to spray water onto the surface. Treatments included a wood fiber blanket, a straw/coconut blanket, a straw blanket, a bonded fiber matrix, and disk-anchored straw mulch for natural rainfall events. For the rainulator events, a bare soil treatment also was used. Biomass, percent cover, and species composition also were measured at the research site. Five runoff events from natural rainfall were measured and revealed very little difference in sediment production between the straw, straw/coconut, and the wood fiber blankets. These blankets had approximately one-tenth the erosion that was observed for the straw-mulch plots. The impact of the erosion control treatment was substantial for early season artificial events. The sediment loading rates from the blankets and bonded fiber matrix plots were roughly one hundred times smaller than the bare soil plots and 10 times smaller than the straw mulch plots. For late season events, the erosion from these products were approximately one-half of that from straw mulch treatments.

This report presents the results of a field study on the performance of erosion control products under artificial rainfall conditions, bed shear partitioning using a hydraulic flume, and regression analysis of previously published data. Ninety-six runs of different plot lengths, erosion control treatments, vegetative cover, and initial moisture contents were gathered and analyzed. Above-ground biomass varied substantially within the growing season, runoff was most strongly influenced by initial moisture content, and sediment load was substantially reduced using erosion control products and mulches. In the hydraulic flume experiments, the percentage of the total shear acting on soil particles was less than 13.2% for all tests. Failure to obtain a large data base of product characteristics greatly limited the use of regression analysis to explain the performance of erosion control blankets.

This manual, intended for counties, townships and local units of government, provides guidelines and methods for effective erosion control practices on low volume roads. Local agencies are required to develop erosion control plans and abide by the National Pollutant Discharge Elimination System (NPDES) permit requirements. Detailed information is provided to guide the user through both Phase I and II of the NPDES permit process, and help is given for dealing with local watershed districts and other agencies. This manual provides guidance for maintenance activities, and case studies outlining best management practices.

It has been about fifteen years since soil bioengineering and bioengineering technology have been used in projects to protect slopes and river banks against erosion. Now many consulting firms as well as state and federal agencies promote and practice these techniques. Despite a widespread support of these techniques, many projects have failed. Therefore, it is deemed necessary to develop a set of design guidelines to ensure a higher rate of success. In order to develop design guidelines for soil bioengineering and bioengineering technology, a pilot study was conducted to determine the amount of work already done in these areas, and to define the existing research needs. This report comprises (a) a summary of literature review, (b) interviews with eleven practitioners in the field, (c) an evaluation of three projects done in Minnesota, (d) current research needs, (e) and a brief evaluation of three sites in the vicinity of the Twin Cities area as potential outdoor laboratories to conduct research in the needed areas. It also includes a summary of a site visit of the department of Soil Bioengineering and Landscape Construction at the University of Agricultural Sciences in Vienna, Austria. The study shows that a significant number of studies have been done on topics related to soil bioengineering techniques. However, these studies mainly address the problems at a micro scale, and hence, there is a gap between existing knowledge and practice. Therefore, there is an urgent need to not only study some of the fundamental processes and mechanisms involved in soil bioengineering techniques, but also to investigate these processes at a macro scale to evaluate their strengths and impacts when applied to streambanks and slopes.

The impact of erosion and sediment from construction sites can be reduced by using a variety of onsite and offsite practices. The WATER model was developed to be a tool to assess the effectiveness of different sediment control practices. The WATER model evaluates risk by performing many simulations of a construction site response for different weather conditions. A particularly important component of the WATER model is the prediction of daily climate variables and storm characteristics called WINDS. This model uses the statistics for the analyzed data to predict many years of possible weather conditions. Predicted weather and storm characteristics are in very good agreement with those observed. The WATER model simulates surface runoff, plant processes, and erosion and sediment transport as major hillslope processes. Four runoff events (spring dry run, spring wet run, fall dry run, and fall wet run) from artificial rainfall conditions were measured.

Various agencies have discussed the possibility of using turbidity as an effluent standard for construction site. Turbidity monitoring can be difficult for dynamic construction sites. This project investigated turbidity relationships for conditions of Minnesota and developed protocols for the design and installation of cost-effective monitoring systems. Turbidity characteristics of fourteen different soils in Minnesota were investigated using the laboratory protocols. Trends in turbidity with sediment concentrations were well represented by power functions. The exponent of these power functions was relatively constant between soils and the log-intercept, or scaling parameter varied substantially among the different soils. A regression analysis for the scaling parameter was a function of percent silt, interrill erodibility, and maximum abstraction. A power value of 7/5 was chosen to represent all soils. The field studies were also used to develop turbidity monitoring systems that would be adaptable to construction sites and to collect turbidity data on construction site runoff. Construction site turbidities often exceeded 1000 NTUs and sometimes surpassed 3000 NTUs.

This report presents an evaluation of wastewaters derived from concrete placement and maintenance and the preparation of best management practices (BMPs). Investigation and documentation of existing practices was done to ensure application to real situations and enhancement of constructability for all BMPs. Laboratory analysis of test specimens was done to provide characterization of factors that are likely to positively or negatively influence concrete wastewater composition. Evaluation of sedimentation and filtration through and absorption by sand and geotextile materials provides a simulation of the known control techniques. Development of a constituent occurrence and control model with a strong statistical base achieved through experimental replication supports development of BMPs that are both environmentally protective and constructible.

This report describes the research conducted by the University of Minnesota and project partners on roadway embankment overtopping by flood water. Roadway overtopping is a major safety concern for Minnesota transportation managers because of the potential for rapid soil erosion and mass wasting resulting in partial or complete failure of the roadway embankment. This multi-year research study focused on various aspects of the roadway embankment overtopping. A robust literature survey was performed to identify research; reports and other published knowledge that would inform the project. A field-based research campaign was developed with the goal of collecting data on the hydraulics associated with full-scale overtopping events. Finally; a series of laboratory experiments were conducted at the St. Anthony Falls Laboratory; University of Minnesota to study the hydraulic and erosional processes associated with embankment overtopping and in particular study of three slope protection techniques under overtopping flow. The largest component of the research project was the laboratory hydraulic testing; which focused on bare soil (base case) and three slope protection technologies. A full scale laboratory facility was constructed to carry out the testing. Three erosion protection techniques were examined including 1) armored sod; 2) turf reinforcement mat; and 3) flexible concrete geogrid mat. Overtopping depths of up to 1-ft were used to determine the failure point of the protection technique and soil on both the 4h:1V and 6V:1H slopes. The full project report details the testing of each protection technique as well as observations and findings made during the testing.

The goal of this project is to develop a sub-soiling regimen that will enhance and be compatible with existing erosion control measures. This project is important in minimizing the effect of construction-induced compaction on the urban and rural landscape. This activity, if successful, will become a building block for use in Best Management Practices (BMPs) that will ensure full vegetative growth post construction, and save on the cost of reapplication of erosion control measures. For a good comparative study, several sites were selected for typical slope and soil type. The study shows that there are low cost benefits to deep tillage of ROW. Heavy clay soils are problematic in that improvements in infiltration could not be detected after a single tillage operation. In lighter sandy soils, the benefits of tillage are such that significant increases in infiltration can be gained following a single pass tillage operation. The differences in tillage implement used could not be detected. The post-tillage aesthetic appeal when using a non-inverting plow (Kongskilde Paraplow) was apparent in this study. The vegetation was largely undisturbed following tillage, and this would be beneficial in preventing erosion on slopes. The ripper and the DMI inverted more soil, and therefore the tillage operation was less appealing to motorists. The relatively low cost of ownership and operation for the tillage is overshadowed by the high land cost when new roads are constructed. Tillage would be beneficial on lighter soils, however the "utility congestion" that is likely in such a scenario would make machinery management difficult.