Degradation of the nation's waters continues to be a problem and urban runoff is a large contributor to it. New stormwater management policies stress the importance of using stormwater control practices that reduce the quantity and improve the quality of stormwater runoff. The new approaches tend to emphasize small-scale, on-site practices over large scale. Yet to achieve water quality benefits, stormwater control practices must be maintained over time. Maintenance costs of these facilities, however, are poorly understood. A case study of five municipalities around the United States is used to estimate inspection and enforcement costs for each case site. Maintenance activities and costs were collected at the case sites for the following stormwater controls: dry ponds, wet ponds, wetlands, bioretention facilities, sand filters, and infiltration trenches. Cost estimates indicate that inspection and enforcement is not influenced by type. Maintenance cost estimates change depending on the BMP type. Estimated annual post-construction costs applied to a hypothetical 1,000-acre indicate that moving from large-scale to small-scale stormwater controls has a large impact in terms of financial obligation. / Ph. D.

Due to development of once natural landscapes, also referred to as urbanization, stormwater management has evolved in an effort to address and counteract impairment of waterways in the United States by extensively implementing best management practices (BMPs) or Green Stormwater Infrastructure (GSI). Facilities are installed without any requirement of long-term monitoring; instead relying on lab-tested or assumed pollutant removal efficiencies that often do not translate into field implementation and do not perform as intended and required by regulatory agencies. Monitoring studies have often been applied with variable standards, which lead to inconsistent results and inconclusive data. This study aims to synthesize essential components of a GSI monitoring program based on a review of existing programs (Technology Assessment Protocol – Ecology [TAPE], Technology Assessment Reciprocity Partnership [TARP], etc.). Data from past protocols was used in tandem with historic precipitation data to develop a methodology for creating a local or small region-specific protocol. This methodology was applied to the case study area of Fairfax, Virginia. Results from the study indicate that historic precipitation data and past protocol recommendations can be effectively applied in a local setting to create a more suitable protocol adapted for GSI monitoring in order to confirm designed efficiency. / Master of Science

Construction and maintenance can have huge implications on the long-term functioning of GSI facilities. GSI facilities investigated were bioretention, permeable pavement, sand filters, infiltration trenches, and vegetated swales. This study first highlights the most important construction and maintenance items based on relevant studies and state stormwater manuals. Fairfax County, VA was used as a case study to evaluate the County's current stormwater program and illuminate common maintenance issues found for each GSI type. Data analysis of 3141 inspection records illustrated particular deficiencies for each GSI type and that there are differences between public and private facilities, most likely depending on site conditions and frequency of routine maintenance. Sediment accumulation was found to be the most common maintenance issue (27.8% of inspections), supporting the importance of adequate pretreatment and good housekeeping when implementing GSI. The Northern Virginia Soil and Water Conservation District (NVSWCD) performed a study surveying 63 public bioretention facilities in which they measured ponding depth, filter media depth, ponding area, and infiltration rates. The NVSWCD concluded that deficiencies found in facilities could mostly be attributed to inadequacies during construction. By comparing current post-construction inspections performed by the County to the NVSWCD data, it was found that these County inspections are failing to detect these inadequacies in bioretention facilities from improper construction. It is recommended that MS4s thoroughly record and track construction and post-construction inspection items to improve the longevity of its facilities and better inform future decision making regarding GSI. / Master of Science

In March 2003, many communities in Mississippi fell under National Pollutant Discharge Elimination System (NPDES) regulations and were required to develop Stormwater Pollution Prevention Plans (SWPPPs). This study surveyed those in charge of SWPPPs in Mississippi’s regulated communities to determine the knowledge, efforts, and associated expenses, of complying with Stormwater Phase II regulations as well as what attempts regulated communities made to include urban forestry in their SWPPPs. While results indicated that all respondents were compliant with Stormwater Phase II regulations, regulated communities can improve efforts in several areas to best mitigate stormwater runoff pollution (e.g., public education and urban forestry). Findings will be useful when presented to current and, soon to be, regulated communities in an educational and outreach effort to increase their knowledge levels, reduce incurred costs, increase the effectiveness of their SWPPP, and enhance their ability to utilize urban and community forests as a stormwater mitigation tool.

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / William P. Winslow III / Sports venues require large amounts of parking to facilitate the number of spectators attending an event. The parking, mostly surface, is underutilized when compared to traditional parking lots accommodating daily use. Large parking surfaces alter the natural hydrological cycle by generating large volumes of runoff. Over time, pollutants build up on a parking surface and are discharged into a stormwater drainage system during a rain event. The intent of the research is to investigate the use of Best Management Practices that ultimately reduce the pollutant loads created by stormwater runoff while creating amenities for spectators that could potentially generate revenue. The focus of the study will be on a 400 acre sports venue in Kansas City, Missouri, the Truman Sports Complex. To understand retrofitting stormwater management practices, one must understand how large parking lots are constructed and understand successful examples. Through the use of archival research, interviews and analysis of two parking lot case studies, Northgate Mall in Seattle, Washington and US Cellular Field in Chicago, Illinois, the research analyzed how retrofitting design solutions are utilized to reduce stormwater pollutant loads. Each case study documents a distinct type of retrofitting strategy; bioswales at Northgate Mall and permeable concrete pavers at US Cellular Field. Using the Design Point Method developed by the Center for Watershed Protection, the research analyzes each case study retrofit design solution - conceptually and post construction. The Design Point Method allowed the research to measure the success of retrofitting strategies and informed the research to as to how the strategies could be implemented at the Truman Sports Complex. The conclusion of the project is a retrofit design solution of a surface parking lot at the Truman Sports Complex. Using the Design Point Method as an analysis tool, the final study provides compelling evidence that retrofitting existing surface parking lots at sports venues using Best Management Practices provides a sustainable solution to reducing pollutant loads while creating the potential for enhancing the tailgate experience for the sports fan.

The stormwater retention pond is a best management practice used for the improvement of runoff water quality before it discharges into larger surface waterbodies. A vortex-type retention pond, called the Nautilus PondTM, is a new design approach for stormwater retention ponds that is expected to produce an internal flow pattern in the pond that is more conducive to removal of sediments from runoff. Since many existing stormwater retention ponds were originally designed only for flood control, most of the ponds are subject to large dead zones, severe short-circuiting and short retention times, which can limit sediment retention in the ponds. In this study, the robustness of the design of the Nautilus PondTM was evaluated by assessing its residence time distribution (RTD) characteristics, flow pattern and sediment deposition patterns under various conditions of flow in the pond. The study was carried out in two physical scale models of a simplified Nautilus PondTM: one with a scale ratio of 1:30.775 for an aspect ratio of 100:2, and the other with a scale ratio of 1:13.289 for a pond of 50:2 aspect ratio. The aspect ratio is the ratio of the pond diameter at its water surface (top width) to the depth of flow, 2 m at corresponding design flow rates, in the pond. First, the RTD characteristics and flow patterns in the ponds were investigated using tracer mass recovery and flow visualization tests allowing different times for steady flow development (flow development time) for the design flows corresponding to 4 m3/s in the 100:2 prototype pond and 1 m3/s in the 50:2 pond. Then, tracer tests were carried out at different flow rates to investigate its effects on the RTD characteristics in both model ponds. The deposition patterns of approximately 50 micron sediment particles (prototype size) were also observed. The best position of a berm around the pond outlet was determined for the 100:2 pond by comparing the RTD characteristics and the sediment deposition patterns in the pond for three different positions of the berm. The residence time distribution characteristics and the sediment deposition pattern were also assessed for the 50:2 pond with a berm placed in a position equivalent to the best position identified in the 100:2 pond tests. It was found that the RTD curves at design flow rates of 4 m3/s and 1 m3/s for different flow development times were very similar to each other for both pond aspect ratios; the flow development time was found to have little effect on the flow characteristics of the ponds. The average baffle factors, short-circuiting indices and Morril dispersion indices were 0.41, 0.20 and 4.1, respectively, for the 100:2 pond aspect ratio, whereas these were 0.23, 0.05 and 8.6 for the 50:2 pond. The flow rate was found to have a significant effect on the RTD characteristics of both ponds. There were multiple peaks in the RTD curves for the lower flow rates tested for the 100:2 pond. This was thought to be a result of the low inflow momentum and high aspect ratio of the pond. As the flow rate was increased, the residence time distribution curve had a single, lower peak. In both ponds, an increase of flow rate caused the baffle factor and short-circuiting index to decrease and the Morril dispersion index to increase indicating that the inflow spent a shorter time in the pond. The sediment deposition pattern tests in both ponds without the berm around the outlet showed that a higher quantity of sediments deposited in the outer peripheral region of 100:2 pond. The 50:2 pond deposited a small amount of sediment along the periphery due to the high velocity inflow jet and lower aspect ratio of the pond. The best position of the berm among those tested was found to be at the 60% of pond bed radius from the center. Though the RTD characteristics for the 100:2 pond with different berm positions were very similar to each other, the 100:2 pond with the berm position at 60% of pond bed radius deposited most of the sediments outside the berm. The RTD characteristics in both ponds showed significant improvement with a berm at the 60% of radius position compared to the ponds without a berm. This improvement was more significant for the 50:2 pond than for the 100:2 pond. Further, the sediment deposition pattern in 100:2 pond with berm at 60% of bed radius showed that the larger sized sediment particles mainly deposited outside the berm and the finer particles deposited inside the berm. The 50:2 pond did not show any significant difference in particle size distribution of the sediments deposited inside and outside of the berm.

More than 54% of the world population lives in urban areas, and this percentage is projected to increase rapidly in future years. This growth significantly affects the hydrological cycle, which translates into social and economic costs due to urban flooding. This thesis develops a procedure to evaluate the current storm water infrastructure using Airborne LiDAR data. This evaluation is essential to mitigate and prevent the effect of floods in urban areas. Airborne LiDAR data provides the elevation data necessary to characterize the elements involved in the storm water system. The processing of this data, digitization, and characterization of the storm drainage system is computed with ArcGIS, Geographic Information System (GIS) software. Scenarios for 4 return periods (2, 10, 25 and 100 years) are modeled using StormCAD in order to evaluate the capacity of the stormwater sewer system in the northwest area of The University of Texas at Austin main campus. The performance of the drainage system might work under strain for a 100-year storm event; therefore, it is suggested to modify the pipe sizes to prevent flooding in the area analyzed. The results indicate that the methodology proposed for evaluating the current conditions of a stormwater drainage system produces valid results, but can be improved using Ground-based LiDAR data. / text

2 pp. / RainScapes are the ultimate in water efficient landscaping. RainScapes are beautiful landscapes that once established rely entirely on rain and stormwater (gray water too if available)while preserving tap water for indoor and drinking water needs.

No description available.

Thesis (M.S.)--University of Tennessee, Knoxville, 2001. / Vita. Includes bibliographical references (leaves 72-76). Also available via the Internet.