ABSTRACT The City of Richmond, Virginia conducted a study to evaluate local drainage system in its downtown business district to remedy conditions that cause flooding more than once in a twoyear period. The main goals of this study are to evaluate the capacity of the storm water collection system in the downtown area to handle the 2-year storm event, identify system constraints and provide recommendations for improvement. The study area, Shockoe Bottom watershed, is a 65-acre sub-basin located within the City’s largest combined sewer watershed, Shockoe Creek watershed, which has an existing land area of approximately 8,000 acres.
Extensive hydrologic and hydraulic modeling and analyses on the existing Shockoe Bottom drainage system, including the Dock Street Pumping Station, the Northeast Interceptor, and the stormwater inlets in the Shockoe Bottom watershed and in adjacent watersheds, were conducted. Field investigations included an inventory of the number and size of the existing stormwater inlets, and connectivity of roof rain leaders. The study showed that the storm water ponding in the downtown low-lying areas may be caused by: (1) Flows discharging into the Shockoe Box Sewer exceed the capacity of Dock Street Pumping Station. This is caused by: a) Excess flows transferred into the Shockoe Box Sewer from the Northeast Interceptor watershed and, b) Flow transferred from the Shockoe Arch Sewer into the Shockoe Box Sewer through existing gates between the Northeast Interceptor and the Shockoe Arch Sewer. (2) Excess overland runoff flow, which exceeds the capture capacity of the existing storm water catchments. This excess overland flow is from the downtown watershed itself and from the adjacent watershed to the east.
Based on these findings, a series of capital improvement projects were identified and evaluated to minimize the nuisance flooding in the downtown area. Benefit-to-cost analyses showed that the Northeast Interceptor improvements, installation of more stormwater inlets near the low points susceptible to flooding, as well as modification of Dock Street pumping station operation are the most cost effective measures.
INTRODUCTION The City of Richmond is located at the falls of the James River. The older portion of the City is served by a combined sewer system (CSS) that comprises about 12,000 acres or 30% of the City’s total area. There are currently 29 CSO outfalls identified in City’s VPDES permit, most of which are located along the James River and its tributary, Gillies Creek. The largest basin in the system is the Shockoe Creek combined sewer area, which is approximately 8,000 acres or about 2/3 of the CSO system. The downtown Shockoe Bottom area is a 65-acre watershed tributary to the Shockoe Box sewer, as shown on Figure 1.
Being the lowest point on the north side of James River, the Shockoe Bottom area is subject to flood from both the James River and interior rainfall event. In 1994, the City completed the flood wall project which protects Shockoe Bottom from the river flooding. Since then, business and development have quickly thrived in the bottom area. However, it has been observed that the low-lying areas in Shockoe Bottom, such as Pine Alley, Walnut Alley and the Farmers Market, have experienced local flooding more than once in a two-year period (see Figure 2). The purpose of this study was to evaluate the capacity of the storm water collection system in the Shockoe Bottom to handle the 2-yr storm event, identify system constraints and provide recommendations for improvement.
Architect: Johann van den NoortInstalled by: Schagen BVTiming: 1998-2004The ProblemThe company, Astellas Pharma Europe (previously Yamanouchi) produces expensive pharmaceutical medicines and in 1998 this area was hit by very heavy rainfall which caused extensive flooding in the immediate vicinity of this factory.At board level, a decision was taken to investigate the feasibility of either moving the whole factory and relocating it to higher ground, or building a flood wall around the factory to protect it.The...
The installation of a Mono Stormscreen unit now allows the incoming raw sewage to be thoroughly screened at storm level, ensuring large solids are retained in the main flow to treatment and that the stormwater discharge from inlet meets consent requirements.
The Stormscreen is designed to provide a self-cleaning, self-powered alternative to existing mesh screens for handling storm overflows. Ideal for this type of variable flow application, the unit at Little Mill is mounted on a channel overflow weir and has a...
ABSTRACTHurricane Katrina and its aftermath damaged the water distribution system and the sewerage collection system in the City of New Orleans, creating health and safety issues for both the general public and emergency and recovery personnel working in the city. The efforts by the Sewerage and Water Board of New Orleans (S&WB) in restoring these systems has been critical in making the city safe and functional for the return of its citizens.
INTRODUCTIONSince 1899, the S&WB has constructed and operated...
ABSTRACTCombined sewer overflows (CSOs) are gaining the attention of environmentalists and regulators. Communities are taking steps to decrease the number of overflow events and to reduce the amount of pollutants discharged in these events. Like most communities in the Northwest, Mount Vernon, Washington, has a mandate to reduce CSOs to less than one event per year. Engineers, regulators, and City staff members investigated cost-effective means to implementCSO reduction programs. This paper summarizes the cost-effe...
The Rio Salado Environmental Restoration Project (Project) has been 40 years in the making and is the first of its kind in the desert southwest. It has become the benchmark for future river restoration Projects. The Project restores a 5-mile section of the Salt River (Rio Salado) that goes through the very core of the City of Phoenix. The Salt River provides essential 100-year flood protection for the City of Phoenix. The Project changes a dry riverbed eyesore of debris and gravel pits back into restored native...
Introduction
Engineers are nowadays expected to not only be skilled in technical matters, preparing calculations and designs, but also to know far more about risk analysis than ever before. In almost all aspects of engineering, risk analyses are now commonplace, with many of the design codes used based on statistical analyses. In the fields of river and coastal engineering it is nowadays expected that risk analyses will be undertaken as a standard element of a project. Part of this analysis is to determine the...
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Progress Ridge, a 110-acre mixed-use development, is designed around a reclaimed
rock quarry on the border between the cities of Beaverton and Tigard, Ore. The
quarry is now an 11-acre lake surrounded by 746 high-density residential units,
a commercial town center and 43 acres of parkland.
Beaverton requires on-site detention of stormwater runoff to control the volume
of runoff sent to downstream channels. This protects channels from scouring
and reduces potential...
Medium voltage (2.3kV to 6.6kV) motors are the norm in major Asian pumping plants in Asia to drive their water or waste water pumps. Pumping stations have to control both flow as well as pressure over varying consumer demand. Due to higher demand on productivity and efficiency, the trend for new installations is to design plants with electrical variable speed drives for their motor-pump sets to increase quality, reliability, and productivity over conventional pressure control methods. Energy efficient, modern,...
Introduction
The flow variations in sewers have been modelled for several years with a comparatively high degree of accuracy as far as the diurnal variations and responses to climatic conditions are concerned. However, until comparatively recently the variations in flow due to fluctuations in groundwater levels, soil storage capacity and wetness of the catchment have only been modelled in basic terms. For the past decade it has been possible to use runoff models that respond to the increasing wetness of the...
The UK’s prestigious Royal Society recently held a discussion group on the subject of Flood Management and Climate Change. With much of the Northern Hemisphere approaching the winter flooding season, we spoke to Wallingford Software’s David Fortune to find out the role of modelling in flood forecasting and flood management. He set out his ideas as follows:
We must remember first that, while we might expect more flooding as our climate changes, it is not a simple matter to predict the extent of flooding. It’s not...
Introduction
“Sustainable Development” is an increasingly important concept in most industries today, and one in which the water industry has been making rapid progress for over a decade. In countries around the world, including the USA, Europe, and Australia, Sustainable Urban Drainage (SUD) structures - permeable pavements, ponds, and the like - are reducing the volumes of direct urban runoff, and helping to resolve problems such as flooding and pollutant spills to rivers.
However, until recently, waste...
Abstract
A long-term environmental monitoring program is providing hydrologic data that demonstrates poplar trees are influencing groundwater flow at the J-Field site, Aberdeen Proving Ground, Maryland. Advanced data collection and analyses techniques have enabled researchers to construct a water budget for the study area and to estimate the amount of groundwater the trees are transpiring on a daily and annual basis. During the growing season, groundwater flow is influenced by the transpiration activities of the...
Characterization of groundwater flow regimes in fractured bedrock aquifers on Southern Vancouver Island and the Gulf Islands of British Columbia are presently based on simple hydraulic testing methods and analytical models. Transmissivity, storativity are derived from porous media (radial flow) analytical models that do not fully represent the more complex boundary conditions inherent to fracture bedrock aquifers. Geological and horizontal loop electromagnetic (HLEM) surveys were used to characterize the lithology...
Introduction
Increasing concerns about the potential risks of anthropogenic climate change over the past ten years have led to a series of international conferences intended to combat climate change and its adverse effects. However, the Kyoto Conference of the Parties to the Framework Convention on Climate Change (FCCC) and, more so, the conference in Buenos Aires revealed the tremendous complexity of the climate change issue, which makes consensus about necessary mitigation measures almost impossible. Not...
Where I live, in eastern, northern, southeastern Pennsylvania (you figure it out), nights are beginning to chill. I`ve noticed this for two reasons. First, the temperature is dipping below 50. Second, insects have begun finding their way inside the house. We capture most of the little buggers and release them but sooner or later someone reaches for a pesticide. We`ve already dealt with fleas on my son`s cat who recently moved home with him.
Now, let`s understand something. Pesticide is a general term for more...
The use of compost in various environmental applications is one of the most intensive areas of compost research being pursued today. The high organic matter content and biological activity of compost makes it effective for use in a variety of applications. Five of these will be reviewed in this article: erosion control, revegetation, biofiltration, bioremediation, and wetlands construction.
EROSION CONTROL
Erosion control is a relatively new and promising application for compost. Research has shown that...
The need to upgrade dairy waste management practices to overcome pollution problems is leading more farmers to seek solutions with anaerobic digestion technology. Two recent examples of this trend are underway at California sites.
The Cal Poly Dairy is located adjacent to the California Polytechnic State University campus in San Luis Obispo. The dairy milks 180 cows with a total population of over 350 animals, including heifers and calves. Most of the herd is housed in freestall barns. About 90 percent of the...
Abstract
The mechanisms controlling heavy metal leaching have been investigated in a pilot landfill containing cemented municipal solid waste incinerator flue gas scrubber residues. Leachate composition with respect to Cd, Cu, Pb, and Zn has been determined as a function of hydrological and geochemical properties of the landfilled material. During dry periods the leachate composition was constant. During rain events the leachate was diluted with rain water. The change in concentration of the elements in the...
A pilot study for delineating wellhead protection areas was undertaken in Cacapava, Brazil, which integrated three-dimensional capture zone modelling with available groundwater and contaminant-source databases, using a four-step process. A contaminant source inventory was developed and each source was ranked based on its potential impact. Next, the thickness of the unsaturated zone and the surficial soil characteristics were used to define regions of higher and lower groundwater vulnerability based on travel time...
Introduction
Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
Introduction:
Co-metabolism is one form of secondary substrate transformation in which enzymes produced for primary substrate oxidation are capable of degrading the secondary substrate fortuitously, even though the secondary substrates do not afford sufficient energy to sustain the microbial population. An emerging application involves the injection of water containing dissolved primary substrate (e.g. methane, toluene) and oxygen into ground water to support the co-metabolic breakdown of targeted organic...
Fuel contaminants are generally nonhalogenated. Information presented for nonhalogenated VOCs and nonhalogenated SVOCs may also be appropriate for many of the fuel contaminants presented in this subsection.
Contamination by fuel contaminants in the unsaturated zone exists in four phases: vapor in the pore spaces; sorbed to subsurface solids; dissolved in water; or as NAPL. The nature and extent of transport are determined by the interactions among contaminant transport properties (e.g., density, vapor pressure,...
In-well vapor stripping technology involves the creation of a ground-water circulation pattern and simultaneous aeration within the stripping well to volatilize VOCs from the circulating ground-water. Air-lift pumping is used to lift ground-water and strip it of contaminants. Contaminated vapors may be drawn off for aboveground treatment or released to the vadose zone for biodegradation. Partially treated ground-water is forced out of the well into the vadose zone where it reinfiltrates to the water table....
Introduction Sustainability or `sustainable development` has become a term which is frequently applied to land use and social planning and resource issues. Sustainability is a concept which draws attention to development practices which can degrade natural ecosystems and deplete natural resources. If development is defined broadly to include any cultural activity, then sustainable development may be defined as any practice that meets the needs of the present population without compromising the ability of future...
` Growing volumes of both industrial and municipal wastewater are being discharged to surface waters but the treatment provided frequently is inadequate to protect the desired uses of the receiving waters. With limited resources in terms of both institutional capacity and finance, governments face difficult choices in optimizing their investments in municipal systems and establishing practical requirements for industrial wastewater treatment. This note presents an approach to making coherent decisions on levels...
` In order to determine the impacts of a particular discharge on ambient water quality, it is usually necessary to model the diffusion and dispersion of the discharge in the relevant water body. The approach applies both to new discharges and to upgrading of existing sources. This note provides guidance on models that may be applicable in the context of typical Bank projects.`
Introduction
Mathematical models can be used to predict changes in ambient water quality due to changes in discharges of wastewater. In...
The U.S. Department of Energy`s (DOE`s) Environmental Restoration Program directs the assessment and cleanup of inactive sites and surplus facilities contaminated from previous defense and non-defense-related programs. All cleanup activities must comply with federal, state, Indian Nation, and local laws and regulations. In completing environmental restoration activities, DOE is committed to working with stakeholders to understand technical issues and evaluate alternatives. Two important program goals include...
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