Browsing by Subject "erosion"
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Item Achieving Peak Flow and Sediment Loading Reductions through Increased Water Storage in the Le Sueur Watershed, Minnesota: A Modeling Approach(2015-09) Mitchell, NathanielClimate change, land clearing, and artificial drainage have increased the Minnesota River Basin’s stream flows and the rates at which channel banks and bluffs are eroded. Increasing erosion rates have contributed to higher sediment-loading rates, excess turbidity levels, and increases in sedimentation rates in Lake Pepin further downstream. These issues have motivated the discussion of flood management through either wetland restoration or the implementation of simple detention basins. This study uses the Soil and Water Assessment Tool (SWAT) to assess a wide variety of water retention site (WRS) implementation scenarios in the Le Sueur watershed in south-central Minnesota, a subwatershed of the Minnesota River Basin. Projected flows were used in conjunction with an empirical relationship developed from gauging data to assess changes in sediment-loading rates from near-channel features in the lower watershed. The WRS term is used as a general term for depressional storage areas, and sites could be made into wetlands or detention basins. Sites were delineated as topographic depressions with specific land uses, minimum areas (3000 m2), and relatively high compound topographic index (CTI) values. Contributing areas were manually measured for the WRS delineated. These contributing areas were used with existing depression depths, and different site characteristics to create 210 initial WRS scenarios. The contributing areas measured for the initial scenarios were used to create a generalized relationship between WRS area and contributing area. This relationship was used with different design depths, placement scenarios, and K values to create 225 generalized WRS scenarios. Reductions in peak flow volumes and sediment-loading rates are generally maximized by placing sites with high K values in the upper half of the watershed. High K values allow sites to lose more water through seepage, emptying their storages between precipitation events and preventing frequent overflowing. Reductions in peak flow volumes and sediment-loading rates also level off as WRS extent increases. This reduction in cost effectiveness with increasing site extent is due to the decreasing frequencies of high-magnitude events. The generalized WRS scenarios were used to create a simplified empirical model capable of generating peak flows and sediment-loading rates from near-channel features in the lower watershed. This simplified model is being incorporated into a decision-analysis model portraying a wide variety of management options in the Le Sueur watershed. This tool may better enable local stakeholders to evaluate, select, and promote management scenarios that best address the issues faced in the region.Item Design Considerations for Embankment Protection During Road Overtopping Events(Minnesota Department of Transportation, 2017-06) Marr, Jeffrey D.G.; Hernick, Matthew; Gabrielson, Robert; Mielke, SaraThis 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.Item Impacts of Soil Health Management on Environmental Quality: A Research Review for Minnesota(2022-10) Reilly, Evelyn; Cates, AnnaThis review was undertaken to summarize research on the impact of four in-field practices (cover crops, reduced tillage, perennials, and crop rotations) on nutrient losses, soil carbon, and runoff/erosion in Minnesota. Social, economic, and policy considerations, while highly relevant to agricultural decision making and design of incentives, are beyond the scope of this review. To maximize relevance of findings, this review focused on data from studies conducted in Minnesota, along with data from Wisconsin, Iowa, Michigan, South Dakota and Illinois if applicable. Since Minnesota has unique climatic conditions, findings from meta-analyses were not included, except as background or where regional differences were noted.Item Increasing Participation in the Minnesota Agricultural Water Quality Certification Program (MAWQCP)(2023) Kaste, Grant A; Gross, Peter S; Greene, GraceSince 2012, the Minnesota Department of Agriculture (MDA) has operated the Minnesota Agricultural Water Quality Certification Program (MAWQCP) for farmers in the state. This voluntary program certifies farmers who implement certain conservation practices that aim to improve soil and water quality. Participation in the program has slowed since its inception and remains lower than the MDA would like. This report explores methods to increase participation in the program, evaluates environmental impacts the program has delivered thus far, analyzes the costs and benefits of the program, and assesses stakeholder views of the program. Methods included utilizing available data, outreach to stakeholders, information gathering from various program meetings, and a literature review of relevant research. Our findings indicate a need for more robust data collection regarding the benefits of the program and non-participant insights, more collaboration with industry and similar programs in other states, and marketing of the program on a watershed-level basis and as one of a stack of programs available to farmers. These findings directly support our offered recommendations and other considerations to work towards the goal of improving water quality and growing conservation minded practices.Item Proceedings of the 4th Drainage Water Management Field Day(2011-08-23) Strock, Jeffrey S.; Gupta, Satish; Sands, Gary; Ranaivoson, Andry; Hay, Chris; Talbot, Mike; Magner, JoeItem Proceedings of the 6th Soil and Water Management Field Day(2017-07-18) Strock, Jeffrey S.; Ahaiblame, Lauren; Gupta, Satish; Ranaivoson, Andry; Varga, Tamas; Dalzell, Brent; Hummel, Alexander; Zhang, LuItem RECOVERY OF SEDIMENT CHARACTERISTICS IN MORAINE, HEADWATER STREAMS OF NORTHERN MINNESOTA AFTER FOREST HARVEST(2010) Merten, Eric, C.; Hemstad, Nathaniel, A.; Kolka, Randall, K.; Newman, Raymond, M.; Verry, Elon, S.; Vondracek, BruceWe investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.Item River Bank Erosion in the Minnesota River Valley(2015-12) Kessler, AndrewSediments remain one of the major causes of water quality impairments in the United States. Although soil erosion from agricultural lands has been viewed as the major source of sediment to rivers and lakes, in many watersheds, river banks are also contributing a significant amount of sediments to surface waters. Currently, limited research has been reported on the methods to quantify and to understand the causes and mechanisms that control river bank erosion. The research reported in this dissertation utilized emerging technologies and novel procedures to investigate (1) historic and modern rates of river bank erosion in the Blue Earth River Basin, a major source of sediment to the Minnesota River and Lake Pepin; (2) methods to delineate seeps (a major mechanism of bank sloughing) on the face of river banks and their impact on bank erosion; and (3) water retention capacity of depressional areas across the prairie pot hole regions of the Greater Blue Earth River Basin. The results of this research indicate that river bank erosion is and has been a major source of sediment in the Greater Blue Earth River Basin even before European immigrants began to settle in Minnesota; the return intensity from light detection and ranging (Lidar) can be used to delineate seepage areas on river banks and this along with lidar generated digital elevation model provides an opportunity to quantify seepage impacts on bank erosion; and the historic storage capacity of a prairie pothole landscape such as the Greater Blue Earth River Basin is relatively small (152 mm) and concentrated only in large depressions. This suggests that restoration of depressional areas will unlikely have a major impact on river flows without additional modifications.Item Using BSTEM to Estimate Sediment Erosion in Seven Mile Creek Watershed(2016) Hammer-Lester, Rebecca FSediment has been recognized as an important water contaminant and there has been substantial research into the sources and sinks of sediment on the landscape. However, ravines are an understudied erosive landform. The flashy, intermittent flows in ravines make them difficult environments to study and manage. The goals of this study were to collect data on the hydrology, sediment, and vegetation in ravines and to use that data to model sediment loads in a steep ravine in the Seven Mile Creek watershed in south-central Minnesota. There are many ravines throughout the Seven Mile Creek watershed and the Minnesota River Basin (MRB), of which it is a small part. The MRB carries the largest sediment loads entering the Mississippi River in the state of Minnesota and these sediments are creating problems downstream including rapid infilling of Lake Pepin. In the present study the Bank Stability and Toe Erosion Model (BSTEM) was used along with substantial field data on hydrology, sediment, and vegetation to model sediment loads generated in ravines in the Seven Mile Creek watershed. The results of the study show that substantial sediment loads can be generated in ravines. Sediment loads varied from a few metric tons/reach/year to tens of thousands of metric tons/reach/year with the strongest control exerted by hydrology followed by sediment, slope, and added cohesion from vegetation. The depth to water table and depth and duration of flow exerted strong control on sediment loads. Changing the water table and depth and duration of water flow caused a relative change in sediment load of at least 193% for the whole ravine results. It is hoped that the field data and modeling results from this study can aid researchers in understanding the magnitudes of sediment loads that can be expected in ravines and that it can guide managers in placing best management practices on the landscape in order to decrease erosion and sediment delivery from ravines to larger streams and rivers.