Browsing by Subject "Stormwater management"

Now showing 1 - 4 of 4
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    Evaluation of Problems and Solutions relating to Stormwater Runoff from Roadside Ditches
    (University of Minnesota Duluth, 2008) Brady, Valerie; Breneman, Dan
    Ditches along roads in rural areas are a dominant conveyor of stormwater to streams along the north shore. Loss of forest cover as well as increased rural development can increase runoff amounts, but ditches provide the structure that moves this water quickly to nearby stream channels (Forman and Alexander 1998, Wemple et al. 1996). Ditches capture overland flow from nearby forests, wetlands, homes, and businesses in rural areas and channel the flows to discharge points, often into streams (e.g., Duke et al. 2006). Much of this runoff would have otherwise infiltrated into the ground, evaporated, drained into wetlands, or flowed slowly across the landscape until reaching a natural stream channel (Forman and Alexander 1998). The result is more water reaching streams much faster after rainfall events (Trombulak and Frissell 2000). The resulting high stream flows during and after storms can increase the erosion of susceptible clay banks, increase bank failure rates, damage aquatic habitats, and impair water quality (Forman and Alexander 1998, Wemple et al. 1996). Road runoff and excess sediment are then delivered to the sensitive nearshore zone of oligotrophic Lake Superior. Eleven north shore streams are currently on the state’s impaired waters list for turbidity (http://www.pca.state.mn.us/water/tmdl/tmdl-303dlist.html), and evaluations on both the Knife and Poplar rivers have indicated that increased flows and bank erosion are major contributing factors (Brady and Breneman 2007, 2008). We have also recently seen an increase in the frequency of large rainfall events, consistent with climate change predictions for this region, indicating that the need for runoff control will only increase in importance. Despite their critical role, ditches are seldom the target of active runoff management programs. Governmental officials who are responsible for ditches in the region have not had the resources and techniques available to address this issue comprehensively, even though ditch maintenance and culvert repair often use up large amounts of local government road budgets, and local and state governments (LGUs) are actively seeking solutions to ditch issues. We brought together a cross-section of experts on rural road and ditch issues to identify the role of ditches in protecting water quality, enumerate the most pressing issues and problems with existing ditches, identify ditch stormwater best management practices (BMPs), and prioritize research, technical, and educational needs on ditch runoff management for the North Shore. The outcomes of this project identify the major ditch problems in northeastern Minnesota, identify appropriate BMPs to solve these problems, the obstacles to the installation of these BMPs, and suggest solutions to overcoming these obstacles. We also identify needed research on ditch BMPs and suggest next steps for improving ditches so that they can help protect our streams and our coast.
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    The Lakeside Stormwater Reduction Project (LSRP): Evaluating the Impacts of a Paired Watershed Experiment on Local Residents
    (2011) Eckman, Karlyn; Brady, Valerie; Schomberg, Jesse
    Scientists, city utilities staff, and local environmental engineers teamed up with homeowners to determine the best ways to reduce stormwater runoff from the Lakeside residential neighborhood in Duluth. The Lakeside Stormwater Reduction Project (LSRP) used a paired-watershed approach to assess the results of diverse stormwater treatments in the Lakeside neighborhood of Duluth on stormwater runoff into Amity Creek. The project investigated various installations that reduce runoff and can be easily maintained by homeowners. The goal was to identify effective methods to reduce runoff contributing to problems in Amity Creek and the Lester River. To complement extensive biophysical monitoring, a knowledge, attitudes and practices (KAP) study was done in April 2008. The purpose was to obtain baseline human dimensions data; assess residents’ willingness to participate in the project; and to identify possible barriers to adoption. Baseline information and residents’ views about stormwater issues were obtained in April 2008. The first-round KAP data was used to refine project design, and to identify possible barriers to participation. The study was repeated with the same sample in September 2010 to evaluate outcomes and impacts. Comparison of the pre and post KAP data shows a significant increase in respondent knowledge about stormwater, a positive shift in attitudes, and strong evidence of adoption of stormwater practices as a result of project efforts. The project successfully increased awareness among residents about the impacts of stormwater on Amity Creek and the Lester River, and fostered adoption of stormwater management practices by homeowners, even in the control sample.
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    Miller Creek Stormwater Modeling
    (University of Minnesota Duluth, 2000) Schomberg, Jesse; Richards, Carl; Host, George E
    The US EPA’s Stormwater Management Model (SWMM) was used to model stormwater runoff volumes and pollutant concentrations in Miller Creek, located in Duluth, Minnesota. The quantity model was calibrated and validated with two years of hourly gage data for three sites along the creek. The quality model had minimal calibration from pollutant loading data for four subcatchments, and was meant for use as a comparative tool to analyze relative changes in pollutants based on various scenarios. As expected, commercial and industrial areas with high amounts of impervious surfaces had a significant impact on the flow volumes, resulting in higher, flashier peaks than undeveloped portions of the watershed. Of the four pollutants modeled (total dissolved solids, total suspended solids, nitrate-Nitrogen, and total Phosphorus), developed areas contributed the majority of all pollutants.
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    Water quality characteristics of three rain gardens located within the Twin Cities Metropolitan Area, MN.
    (2010-05) Elliott, Sarah Marie
    Rain gardens are becoming an increasingly popular feature of Low-Impact Development. They promote decentralized stormwater management by treating stormwater runoff on-site. Rain gardens are effective because they store and infiltrate water allowing biogeochemical processes to occur, thereby removing pollutants from the runoff. Ensuring that rain gardens are functioning properly can be achieved by monitoring studies and visual assessments. This study focuses on the results from a water quality monitoring study and supplements the results with visual inspections of each site. Water quality benefits of rain gardens have been inconsistent and depend on various factors including size of rain garden, design specifications, location, vegetation, and contributing area. The U.S. Geological Survey monitored the water quality in three rain gardens located in the Twin Cities Metropolitan Area, Minnesota. The objective was to compare and contrast water quality characteristics from rain gardens with different designs and contributing area land uses. Representative water samples of the inflow, overflow, vadose zone, and groundwater were analyzed for nutrients typically found in urban stormwater runoff. Generally, lower median concentrations of nitrogen, phosphorus, and total suspended solids were found in the vadose zone and groundwater compared to the inflow, suggesting good performance in terms of water quality benefits. One site exhibited no difference in dissolved phosphorus concentrations; believed to be a result of the low concentrations entering the garden. Higher chloride concentrations were found in the soil and ground water compared to the inflow at two sites. Good evidence of nutrient removal in rain gardens resulting in relatively cleaner or unaffected recharge water reaching local ground water supplies was found from this study. Visual inspections of the three rain gardens provided additional evidence that these three sites are functioning well. There did not appear to be any major structural failures. The vegetation at each site also appeared to be healthy; however, the presence of wetland species and noxious weeds highlights the importance of maintenance.