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1.
Abstract: A numerical model has been developed to simulate the hydraulic and heat transfer properties of a stormwater detention pond, as part of a simulation tool to evaluate thermal pollution of coldwater streams from stormwater runoff. The model is dynamic (unsteady) and based on principles of fluid mechanics and heat transfer. It is driven by hourly weather data, and specified inflow rates and temperatures. To calibrate and validate the pond model field data were collected on a commercial site in Woodbury, Minnesota. The relationship between pond inflow and outflow rates to precipitation was effectively calibrated using continuously recorded pond levels. Algorithms developed for surface heat transfer in lakes were found to be applicable to the pond with some modification, resulting in agreement of simulated and observed pond surface temperature within 1.0°C root mean square error. The use of an unshaded pond for thermal mitigation of runoff from paved surfaces was evaluated using the pond model combined with simulated runoff from an asphalt parking lot for six years of observed rainfall events. On average, pond outflow temperature was 1.2°C higher than inflow temperature, but with significant event‐to‐event variation. On average, the pond added heat energy to runoff from an asphalt parking lot. Although the pond added total heat energy to runoff, it did reduce the rate of heat outflow from the pond by an order of magnitude due to reductions in volumetric outflow rate compared with the inflow rate. By reducing the rate of heat flow, the magnitude of temperature impacts in a receiving stream were also reduced, but the duration of impacts was increased.  相似文献   

2.
Abstract: Runoff from urban catchments depends largely on the amount of impervious surface and the connectivity of these surfaces to the storm sewer drainage system. In residential areas, pervious lawns can be used to help manage stormwater runoff by intercepting and infiltrating runoff from impervious surfaces. The goal of this research was to develop and evaluate a simple method for estimating the reduction in stormwater runoff that results when runoff from an impervious surface (e.g., rooftop) is directed onto a pervious surface (e.g., lawn). Fifty‐two stormwater runoff reduction tests were conducted on six residential lawns in Madison, Wisconsin during the summer of 2004. An infiltration‐loss model that requires inputs of steady‐state infiltration rate, abstraction (defined here as surface storage, vegetation interception and cumulative total infiltration minus steady‐state infiltration during the period prior to steady‐state), and inundated area was evaluated using experimental data. The most accurate results were obtained using the observed steady‐state infiltration rates and inundated areas for each test, combined with a constant abstraction for all tests [root mean squared (RMS) difference = 1.0 cm]. A second case utilized lawn‐averaged steady‐state infiltration rates, a regression estimate of inundated area based on flow‐path length, and lawn‐specific abstractions based on infiltration rate (RMS difference = 2.2 cm). In practice, infiltration rates will likely be determined using double‐ring infiltration measurements (RMS difference = 3.1 cm) or soil texture (RMS difference = 5.7 cm). A generalized form of the model is presented and used to estimate annual stormwater runoff volume reductions for Madison. Results indicate the usefulness of urban lawns as a stormwater management practice and could be used to improve urban runoff models that incorporate indirectly connected impervious areas.  相似文献   

3.
    
This study examines the use of bioretention as a strategy to reduce the thermal impact associated with urban stormwater runoff in developing cold water stream watersheds. Temperature and flow data were collected during 10 controlled runs at a bioretention facility located in Blacksburg, Virginia. It was determined that bioretention has the ability to reduce the temperature of thermally charged stormwater runoff received from an asphalt surface. Significant reductions in peak and average temperatures (p < 0.001) were observed. However, this facility was unable to consistently reduce the temperature below the threshold for natural trout waters in Virginia. The ability of bioretention to reduce runoff volume and peak flow rate also serves to reduce the hydrothermal impact. An average thermal pollution reduction of nearly 37 MJ/m3 was calculated using an adopted threshold temperature of 20°C. Based on the results of this study, it was concluded that properly designed bioretention systems have the capability to reduce the thermal impact of urban stormwater runoff on cold water stream ecosystems.  相似文献   

4.
Abstract: Pollutant loading from storm runoff is considered to be an important component of nonpoint source pollution in urban areas. In developing countries, because of the accelerated urbanization and motorization, storm runoff pollution has become a challenge for improving aquatic environmental quality. An effective storm runoff management plan needs to be developed, and questions concerning how much and which proportion of a storm should be treated need to be answered. In this study, a model is developed to determine the fraction of storm runoff that needs to be treated to meet the discharge standard within a given probability. The model considers that the pollutants can be mobilized during the early stage of a storm. The model is applied to a field study of polycyclic aromatic hydrocarbons (PAHs) in road runoff in Beijing, China. In this case, the probability that the PAH load will be mobilized with suspended sediments by the earlier portion of the flush is 73%. Given the high PAH loading in the study area and the referenced discharge standard, the probability that the entire runoff should be captured and treated is 94%. Thus, urban planners need to consider treatment systems for the majority of the storms in this area, whether the PAH load is in the first flush or not. This methodology can be applied to other regions where PAH loads may result in different management outcomes.  相似文献   

5.
Welker, Andrea L., James D. Barbis, and Patrick A. Jeffers, 2012. A Side‐by‐Side Comparison of Pervious Concrete and Porous Asphalt. Journal of the American Water Resources Association (JAWRA) 48(4): 809‐819. DOI: 10.1111/j.1752‐1688.2012.00654.x Abstract: This article compares the performance of two permeable pavements, pervious concrete and porous asphalt, that were installed side‐by‐side in fall 2007. Because the pavements are located directly adjacent to one another, they experience the same vehicle loads, precipitation, and pollution loads. These permeable pavements are part of an infiltration stormwater control measure (SCM). This article focuses on the comparison of water quality parameters, maintenance and durability, and user perception. Eleven different water quality parameters were analyzed at this site for 19 different storm events over a one year period: pH, conductivity, total suspended solids, chlorides, total nitrogen, total phosphorus, total dissolved copper, total dissolved lead, total dissolved cadmium, total dissolved chromium, and total dissolved zinc. Results from the two pavement types were compared using the Mann–Whitney U‐test. The only parameter that was found to be statistically different between the two pavements was pH. Periodic inspection of the two pavement types indicated that after two years of use both pavements were wearing well. However, there was some evidence of clogging of both pavements and some evidence of surface wear. A survey of users of the lot indicated that the perception of these permeable pavements was favorable.  相似文献   

6.
ABSTRACT: The implementation of various bioretention systems was analyzed, including rain gardens, vegetated swales, trenches, and infiltration basins in the St. Francis subdivision, Cross Plains, Wisconsin. Through the examination of archival data and interviews with key participants, it was found that although regulatory and political pressures encouraged the inclusion of bioretention, current standards for storm water management prevailed. The developers had to meet both existing requirements and anticipated rules requiring infiltration. As a result, bioretention systems simply supplemented, rather than replaced, traditional storm water practices. The confusion surrounding dual standards contributed to substantial delays in the negotiations among relevant stakeholders in the watershed. It is concluded that the St. Francis subdivision serves as both a cautionary tale and a bioretention success story. As a caution, this situation demonstrates the need for careful review and refinement of existing storm water ordinances to incorporate water quality improvement technologies, such as bioretention. The demonstrated success of the St. Francis development, however, is that it became a positive prototype for best management storm water practices elsewhere in the region. In addition, the water quality monitoring data from the site has contributed to development of a new county ordinance, the first in Wisconsin to address both quantity and quality of storm water runoff.  相似文献   

7.
    
This unique study evaluates the cumulative 16‐year lifetime performance of a wetland retention basin designed to treat stormwater runoff. Sediment cores were extracted prior to basin excavation and restoration to evaluate accretion rates and the origin of materials, retention characteristics of fine particulate matter, and overall pollutant removal efficiency. The sediment and organic layers together accreted 3.2 cm of depth per year, and 7.0 kg/m2/yr of inorganic material. Average annual accretion rates in g/m2/yr were as follows: C, 280; N, 17.7; P, 3.74; S, 3.80; Fe, 194; Mn, 2.68; Ca, 30.8; Mg, 30.7; K, 12.2; Na, 2.54; Zn, 0.858; Cu, 0.203; and B, 0.03. The accretion of C, N, P and sediment was comparable to nonwastewater treatment wetlands, overall, and relatively efficient for stormwater treatment wetlands. Comparison of particle size distribution between sediment cores and suspended solids in stormwater runoff indicated the wetland was effective at removing fine particles, with sediment cores containing 25% clay and 56% silt. A majority of the accretion of most metals and P could be attributed to efficient trapping of allochthonous material, while over half the accretion of C and N could be attributed to accumulation of autochthonous organic matter. Stormwater treatment was shown to be effective when physical properties of a retention basin are combined with the biological processes of a wetland, although sediment accretion can be relatively rapid.  相似文献   

8.
  总被引:1,自引:0,他引:1  
Green infrastructure (GI) is quickly gaining ground as a less costly, greener alternative to traditional methods of stormwater management. One popular form of GI is the use of rain gardens to capture and treat stormwater. We used life cycle assessment (LCA) to compare environmental impacts of residential rain gardens constructed in the Shepherd's Creek watershed of Cincinnati, Ohio to those from a typical detain and treat system. LCA is an internationally standardized framework for analyzing the potential environmental performance of a product or service by including all stages in its life cycle, including material extraction, manufacturing, use, and disposal. Complementary to the life cycle environmental impact assessment, the life cycle costing approach was adopted to compare the equivalent annual costs of each of these systems. These analyses were supplemented by modeling alternative scenarios to capture the variability in implementing a GI strategy. Our LCA models suggest rain garden costs and impacts are determined by labor requirement; the traditional alternative's impacts are determined largely by the efficiency of wastewater treatment, while costs are determined by the expense of tunnel construction. Gardens were found to be the favorable option, both financially (~42% cost reduction) and environmentally (62‐98% impact reduction). Wastewater utilities may find significant life cycle cost and environmental impact reductions in implementing a rain garden plan.  相似文献   

9.
ABSTRACT: To quantify the effectiveness of best management practice (BMP) implementation on runoff, sediment, and nutrient yields from a watershed, the Nomini Creek watershed and water quality monitoring project was initiated in 1985, in Westmoreland County, Virginia. The changes in nonpoint source (NPS) loadings resulting from BMPs were evaluated by comparing selected parameters from data series obtained before, during, and after periods of BMP implementation. The results indicated that the watershed-averaged curve number, sediment, and nutrient (N and P) concentrations were reduced by approximately 5, 20, and 40 percent, respectively, due to BMP implementation. The nutrient yield model developed by Frere et al. (1980) was applied to the water quality parameters from 175 storms, but it failed to adequately describe the observed phenomena. Seasonal changes in nutrient availability factors were not consistent with field conditions, nor were they significantly different in the pm- and post-BMP periods. An extended period of monitoring, with intensive BMP implementation over a larger portion of the watershed, is required to identify BMP effectiveness.  相似文献   

10.
Wadzuk, Bridget M., Matthew Rea, Gregg Woodruff, Kelly Flynn, and Robert G. Traver, 2010. Water-Quality Performance of a Constructed Stormwater Wetland for All Flow Conditions. Journal of the American Water Resources Association (JAWRA) 46(2):385-394. DOI: 10.1111/j.1752-1688.2009.00408.x Abstract: Results from a multiyear study demonstrate that a constructed stormwater wetland (CSW) improves urban stormwater runoff quality mitigating downstream impacts. Best management practices, such as CSWs, can comprehensively treat the various scales of stormwater runoff issues. Discrete sample analysis was used to investigate the CSW effect for storm events and base-flow periods on water-quality parameters [i.e., total suspended solids, total dissolved solids, total nitrogen, phosphorous (total and reactive), chloride, heavy metals (zinc, lead, and copper), and Escherichia coli]. The primary finding was that stormwater sediment load was removed through the CSW for all flow conditions during all seasons. The mechanisms responsible for the removal of suspended solids, including slower flow velocity, longer retention times, and vegetative contact, also reduced the mass of nutrients discharged downstream throughout the year. Exceedance probabilities were used to evaluate the expected pollutant reductions of nutrients and to incorporate the effect of natural flow variation on quality. Other findings included the observation that there was no significant difference in the performance of the CSW over two-year-long periods four years apart, indicating that a CSW is effective for an extended period.  相似文献   

11.
Abstract: The quality and quantity of residential stormwater runoff from a control, traditional, and low impact development (LID) watershed were compared in a paired watershed study. A traditional neighborhood was built using typical subdivision standards while a LID design was constructed with best management practices including grass swales, cluster housing, shared driveways, rain gardens, and a narrower pervious concrete‐paver road. Weekly, flow‐weighted, composite samples of stormwater were analyzed for nitrate + nitrite‐nitrogen (NO3 + NO2‐N), ammonia‐nitrogen (NH3‐N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total suspended solids (TSS). Monthly composite samples were analyzed for total copper (Cu), lead (Pb), and zinc (Zn). Mean weekly storm flow increased (600x) from the traditional watershed in the postconstruction period. Increased exports of TKN, NO3 + NO2‐N, NH3‐N, TP, Cu, Zn, and TSS in runoff were associated with the increased storm flow. Postconstruction storm flow in the LID watershed was reduced by 42% while peak discharge did not change from preconstruction conditions. Exports were reduced from the LID watershed for NH3‐N, TKN, Pb, and Zn, while TSS and TP exports increased.  相似文献   

12.
ABSTRACT: A “user-friendly” computer program has been developed for application in personal computers for preliminary design, evaluation, and cost effectiveness analysis of various best management practice (BMP) measures to control stormwater quantity and quality. The algorithms utilize the SCS TR-55 method for calculating runoff hydrographs for a single storm event and a first order pollutant washoff equation to generate pollutographs. Sensitivity analyses based on different policy scenarios is performed on a hypothetical watershed for the purpose of illustration. Three types of BMP measures, namely detention ponds (dry, wet, and extended wet ponds), infiltration trenches, and porous pavements are considered. It is found that the extended wet ponds have the best cost effective performance of the measures evaluated.  相似文献   

13.
    
ABSTRACT: This paper describes a concerted effort by the Taiwan Water Resources Bureau, the City of Taipei, and the Bureau of Fei‐tsui Reservoir Management to protect the water quality in the Fei‐tsui Reservoir.The reservoir is the major source of water supply for over two million people in the metropolitan area of Taipei. Over the years the reservoir has suffered from siltation and more recently eutrophication. The sources of the pollution are traced to the hundreds of tea gardens, rice fields and other agricultural areas in the watershed and to urban sources such as construction sites. Large amounts of nutrients enter the reservoir by way of storm water runoff during storm or typhoon events. Since 1999, various agencies have worked to initiate an effort to reduce nonpoint pollution in the Fei‐Tsui Reservoir watershed. Practices being considered include nonstructural measures such as nutrient management, and structural measures such as swales, detention basins, and wetlands, in addition to erosion and sediment control methods. A number of field tests have been completed on the performance of selected best management practices (BMPs). A strategy for implementing the BMPs at the watershed scale has been developed based on a total maximum daily load (TMDL) analysis that is reported in this paper.  相似文献   

14.
Rosenquist, Shawn E., W. Cully Hession, Matthew J. Eick, and David H. Vaughan, 2011. Field Application of a Renewable Constructed Wetland Substrate for Phosphorus Removal. Journal of the American Water Resources Association (JAWRA) 47(4):800‐812. DOI: 10.1111/j.1752‐1688.2011.00557.x Abstract: Phosphorus (P) is typically the best target to prevent eutrophication in freshwater, a biological process associated with water quality degradation. Constructed wetlands (CW) and other practices that include P removal by sorption processes in substrates can provide economical treatment of stormwater, but have limitations (e.g., large land requirements, loss of removal over time, lack of P recovery). Over the last three years, a multi‐study research program addressed these limitations with a new P management concept. This concept minimizes CW size with a rejuvenation cycle (or rejuvenation) that renews P‐sorption capacity in the CW substrates and enables P recovery for productive use. This study, conducted in Blacksburg, Virginia (July‐September 2009), tested the efficacy of rejuvenation in the field. Methods included replicate cells of two sand substrates monitored for P removal during prerejuvenation and postrejuvenation filtration runs. One substrate contained cast iron filings as a repository for sorption capacity. Results support the following conclusions: (1) P removal is likely dependent on multiple factors including influent P concentration, previous substrate/solution equilibrium, pH, and time; (2) rejuvenation is capable of releasing P adsorbed during stormwater filtration; (3) inclusion of cast iron in substrate promotes additional P removal and enables further removal after rejuvenation; but (4) inclusion of cast iron may limit release of P during rejuvenation.  相似文献   

15.
ABSTRACT: The objective of this study was to evaluate the effectiveness of various land-use practices upon the production of nonpoint source pollutants from small agricultural watersheds in Northern Virginia. Pollutant production at each watershed was determined by individual monitoring stations. Data analysis consisted of a determination of the site specific pollutant yield for similar watersheds subjected to differing crop management approaches. These collected data were then compared to those generated by a parametric, event model developed for this investigation. This synthetic data base was used to eliminate or reduce errors resulting from monitoring site differences and to extend the collected data for additional comparisons.  相似文献   

16.
    
Rainwater harvesting (RWH) has traditionally been implemented in areas with (semi) arid climates or limited access to potable water supplies; however, recent droughts in the humid southeastern United States have led to increased implementation of RWH systems. The objectives of this study were twofold: (1) present usage characteristics and performance results for four RWH systems installed in humid North Carolina (NC) as compared with systems located in arid/semiarid regions and (2) identify system benefits and modifications that could help improve the performance of RWH systems installed in humid regions of the world. For this study four RWH systems were installed in NC. Their usage was monitored for at least one year and compared with similar studies. Results revealed that dedicated water uses and usage characteristics for RWH systems in NC differed from those previously reported in the literature. Two of the systems studied met 100 and 61% of the potable water demand with designated uses of animal kennel flushing and greenhouse irrigation, respectively. The designated uses yielding the greatest potable water replacement were often seasonal or periodic, thus necessitating the need for identifying and implementing secondary objectives for these systems, namely, stormwater management. Otherwise, the expense and effort required to implement RWH systems in humid areas will most likely preclude their use.  相似文献   

17.
    
In the United States, new legislation has given regulatory authorities greater oversight of municipal stormwater management programs. However, estimating the impact of greater oversight on municipal actions is difficult due to the uncertainty in current compliance efforts and their associated costs. This paper seeks to fill this gap through a case study of NPDES stormwater runoff permit reports from municipalities in Southeast Wisconsin. Specifically, this study evaluates the reported actions and expenditures against socioeconomic variables to identify the relationships between cost, socioeconomics, and the best management practices (BMPs) used for compliance. Results indicate that there are distinct differences between municipalities with and without financial and personnel resources, clear high- and low-cost BMPs, and large variation in the practices municipalities implement to meet regulatory requirements. Furthermore, results suggest that regulators should take a flexible and pragmatic approach that considers individual municipal constraints and limitations when exercising greater regulatory authority.  相似文献   

18.
Hancock, Gregory S., Jonathan W. Holley, and Randolph M. Chambers, 2010. A Field-Based Evaluation of Wet Retention Ponds: How Effective Are Ponds at Water Quantity Control? Journal of the American Water Resources Association (JAWRA) 46(6):1145–1158. DOI: 10.1111/j.1752-1688.2010.00481.x Abstract: Wet retention ponds are widely used structural stormwater best management practices (BMPs) with the primary goals of reducing peak flows and extending flow duration. Despite widespread use, few field-based studies have evaluated the success of wet retention ponds at meeting these goals. We determined pond elevation, flow rate, and pond volume over four years in five suburban watersheds in James City County, Virginia. We selected five ponds designed under regulations requiring a 24 hour inflow-to-outflow centroid lag time for a one year, 24 hour design storm. We used pressure transducers to measure pond water surface elevation at 5 min intervals, and calculated pond outflow and volume using rating curves obtained from site stormwater management plans (SWMPs). Peak inflows, peak outflows, and runoff ratios frequently exceeded SWMP calculations in measured events. Four ponds never achieved the required 24 hour inflow-to-outflow centroid lag for storms similar to the one year, 24 hour storm. These BMPs fail to achieve regulatory goals for channel protection because of regulatory loopholes, underprediction of rainfall intensity, unrealistic predictions of postdevelopment flows in SWMPs, and the inability of wet retention ponds to reduce overall runoff volume. While specific to one locality, the shortcomings highlighted suggest similar field-based assessments of retention pond performance are needed in other locations.  相似文献   

19.
    
Stream ecosystems are increasingly at risk for thermal impairment as urbanization intensifies, resulting in more heated runoff from impervious cover that is less likely to be cooled naturally. While several best management practices, including bioretention filters, have been able to reduce thermal pollution, success has been limited. The extent of thermal mitigation required to prevent ecological damage remains unknown. A calibrated runoff temperature model of a case study watershed in Blacksburg, VA was developed to determine the cumulative treatment volume of bioretention filters required to reduce thermal impacts caused by runoff from development in the watershed to regulated biologically acceptable levels. A future build out scenario of the study watershed was also analyzed. Results from this study established that runoff thermal pollution cannot be fully reduced to goal thresholds during all storms using bioretention filter retrofits. While retrofitting significantly decreased temperatures and heat exports relative to the controls, increasing treatment volumes did not really enhance mitigation. Alternate thermal mitigation methods that actively remove runoff volume should be considered where more thermal mitigation is required.  相似文献   

20.
Woltemade, Christopher J., 2010. Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff. Journal of the American Water Resources Association (JAWRA) 46(4): 700-711. DOI: 10.1111/j.1752-1688.2010.00442.x Abstract: Soil disturbances such as excavation and compaction in residential developments affect lawn infiltration rates and stormwater runoff. These effects were investigated via measuring saturated infiltration rates at 108 residential sites and 18 agricultural sites near Shippensburg, south-central Pennsylvania, using a double-ring infiltrometer. Residential sites included four neighborhoods distributed across three soil series classified as hydrologic soil group (HSG) B. Additional parcel data included date of house construction, percentage impervious area, lawn condition, and woody vegetation condition. Measured infiltration rates ranged from 0 to >40 cm/hour. Analysis of variance indicated significantly different mean infiltration rates (p < 0.001) for lots constructed pre-2000 (9.0 cm/hour) and those constructed post-2000 (2.8 cm/hour). Test results were used to determine a “field-tested” HSG for each site, representing disturbed soil conditions. Stormwater runoff was estimated from residential lots for a range of 24-hour design storms using the TR-55 model and several alternative methods of determining curve numbers, including five different representations of soil conditions. Curve numbers and stormwater runoff were substantially higher when based on field-tested HSGs for lots constructed post-2000 compared with lots built pre-2000 and when based on the HSG for undisturbed soils, documenting the magnitude of possible error in stormwater runoff models that neglect soil disturbance.  相似文献   

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