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Hubbard L.E.,U.S. Geological Survey | Keefe S.H.,U.S. Geological Survey | Kolpin D.W.,U.S. Geological Survey | Barber L.B.,U.S. Geological Survey | And 4 more authors.
Environmental Science: Water Research and Technology | Year: 2016

Effluent-impacted surface water has the potential to transport not only water, but wastewater-derived contaminants to shallow groundwater systems. To better understand the effects of effluent discharge on in-stream and near-stream hydrologic conditions in wastewater-impacted systems, water-level changes were monitored in hyporheic-zone and shallow-groundwater piezometers in a reach of Fourmile Creek adjacent to and downstream of the Ankeny (Iowa, USA) wastewater treatment plant (WWTP). Water-level changes were monitored from approximately 1.5 months before to 0.5 months after WWTP closure. Diurnal patterns in WWTP discharge were closely mirrored in stream and shallow-groundwater levels immediately upstream and up to 3 km downstream of the outfall, indicating that such discharge was the primary control on water levels before shutdown. The hydrologic response to WWTP shutdown was immediately observed throughout the study reach, verifying the far-reaching hydraulic connectivity and associated contaminant transport risk. The movement of WWTP effluent into alluvial aquifers has implications for potential WWTP-derived contamination of shallow groundwater far removed from the WWTP outfall. © 2016 The Royal Society of Chemistry.


Parker J.,Environmental Consulting and Technology Inc. | Dawson M.,Sand Creek Consultants Inc. | Montle S.,Center for Community Progress
Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA | Year: 2012

Chevy in the Hole, once the industrial heartbeat of Flint, MI, and the automotive industry, now consists of 130 acres of blighted urban riverfront surrounded by universities, schools, neighborhoods, and hospitals. The City of Flint is using a repertoire of mechanisms by which trees and vegetation can better environmental quality of soils and groundwater, commonly referred to as phytotechnologies, to build a foundation of reuse that cuts costs, recycles wastes, creates green space, protects the environment, and connects the community to this historical site. The basis for this specific project is to utilize trees as both a vehicle for bettering the overall environmental quality of a contaminated, underutilized urban riverfront Brownfield site and a foundation for a green habitat corridor connecting two major universities and stimulate redevelopment in the local neighborhoods. This is an abstract of a paper presented at the 106th AWMA Annual Conference and Exhibition (Chicago, IL 6/25-28/2013).


Quan Q.,Xi'an University of Technology | Dong L.,Xi'an University of Technology | Li J.K.,Xi'an University of Technology | Shen B.,Xi'an University of Technology | Jin C.X.,Environmental Consulting and Technology Inc.
Nature Environment and Pollution Technology | Year: 2014

To achieve more reasonable and effective treatment of urban stormwater, researchers proposed the Low Impact Development (LID) method, which is regarded as a sustainable solution. Studies have shown that the bio-retention system was effective in tackling urban runoff problems and was one of the most commonly used LID. In hydrologic modeling, DRAINMOD has a new application in bio-retention simulation. A model named Hydrologic Performance Tool (HyPer Tool) is proposed based on the output of DRAINMOD simulations on various bio-retention designs. This paper utilized HyPer Tool to simulate the bio-retention system in the urban road runoff in Xi'an, China with different rainfall conditions and characteristics. Meanwhile, this paper discussed and analysed the dynamic changes of pollutants and impurities during bio-retention system runoff purification in the four typical designs of HyPer Tool bio-retention ponds so as to provide an objective evaluation on bio-retention - an urban rainfall-flood management approach.


Kumar A.,Drexel University | Adak P.,Environmental Consulting and Technology Inc. | Gurian P.L.,Drexel University | Lockwood J.R.,RAND Corporation
Journal of Exposure Science and Environmental Epidemiology | Year: 2010

Although approximately 35 million people in the US obtain drinking water from domestic wells, few studies have investigated the risk of arsenic exposure from this source. In this paper arsenic concentrations were modeled for public and domestic wells using a dataset from the US Geological Survey (USGS). Excess lifetime and annual risks for lung and bladder cancer were calculated based on the carcinogenic potency and average arsenic concentrations in public and domestic water supplies. Monte Carlo uncertainty analysis was used to estimate the degree of confidence in these estimations. Results indicated that domestic well users accounted for 12% of the US population, but 23% of overall arsenic exposure from drinking water. Assuming that the new and more restrictive arsenic maximum contaminant limit (MCL) is implemented for public water supplies, it is anticipated that the proportion of people experiencing excess annual fatalities from drinking water from domestic wells will increase to 29% unless corresponding efforts are made to reduce exposures among domestic well users. Differences between public and domestic wells were not consistent across the nation. Public wells tend to tap deeper aquifers than domestic wells, and as a result local arsenic-depth trends can contribute to differences between public and domestic wells. Domestic wells and public wells in the western US have the highest arsenic levels with excess fatality risks estimated to be in the range of 1 per 9300 to 1 per 6600 in these regions. Uncertainty distributions of excess fatalities were developed and resultant uncertainties were propagated in arsenic exposure and potency factor. Uncertainty in the carcinogenic potency of arsenic was the dominant source of uncertainty in most regions, but for domestic wells in the New England and Southeast regions uncertainty in arsenic exposure was dominant, indicating that additional data on arsenic concentrations in these areas would substantially improve regional risk estimates. © 2010 Nature Publishing Group All rights reserved.


Bhat S.,University of Florida | Bhat S.,Environmental Consulting and Technology Inc. | Jacobs J.M.,University of New Hampshire | Hatfield K.,University of Florida | Graham W.D.,University of Florida
Environmental Monitoring and Assessment | Year: 2010

The magnitude, frequency, duration, timing, and rate of change of hydrologic conditions regulate ecological processes in aquatic ecosystems. Conditions are typically characterized using annual-based hydrologic indices derived from daily and/or monthly stream flow data. In this study, we present an alternative approach to identify hydrologic indices based on storm hydrographs. Hydrologic indices derived from longterm daily flow data were compared to those from storm events for two headwater watersheds in Fort Benning, Georgia. Five hydrologic indices derived from daily flow data and storm events shared common features. Storm-based magnitude of mean peak discharge and mean response factor, frequency of bankfull discharge, rate of change in mean slopes of rising, and falling limb of the hydrograph were consistent with the results from long-term daily flow data. The annual flow increases and decreases were well matched by stormflow rising and falling. Both indicators showed one watershed having three times the response rates as compared to the other. Results suggested that select storm-based indices may be used as surrogates to the indices derived from long-term data. © Springer Science + Business Media B.V. 2009.


Bhat S.,Environmental Consulting and Technology Inc. | Danek L.J.,Environmental Consulting and Technology Inc.
Water, Air, and Soil Pollution | Year: 2012

A central wastewater treatment facility was built in 1997 for the town of Suwannee that eliminated 850 inadequately operating on-site sewage treatment and disposal systems. During a study in 1989-1990, Salmonella were detected in Suwannee River water samples upstream and downstream of the town of Suwannee. This study presents the findings of fecal coliform distribution between the years 1996 and 2009 in canals and the main stem of Suwannee River near the town of Suwannee, a coastal area in southeastern USA. Fecal coliforms were measured and assessed to evaluate the water quality before and after the installation of the central wastewater treatment facility. In the canals nearby the town of Suwannee, significant differences in fecal coliform concentrations were detected between the samples collected before and after the operation of the central wastewater treatment facility. Average fecal coliform of 537 most probable number (MPN)/100 ml in the canals in 1996 was reduced to 218 MPN/100 ml after the operation of wastewater treatment facility. The fecal coliform levels in canals decreased significantly in the last 13 years. Even though the average fecal coliform levels in the river was reduced from 170 to 86 MPN/100 ml before and after the installation of the wastewater treatment facility, respectively, the difference was not statistically significant. © Springer Science+Business Media B.V. 2011.


Zhang J.,Capital Normal University | Said A.,Environmental Consulting and Technology Inc. | Ross M.,University of South Florida
Journal of Irrigation and Drainage Engineering | Year: 2010

Hydrologic model calibration is always a challenging and tedious process especially for the calibration of complex models, which includes continuous hydrograph models, requires sophisticated calibration methods. The Hydrologic Simulation Program-FORTRAN (HSPF) is one of the popular and powerful time variable hydrologic models. However, in order to improve the assessment of hydrologic activities in shallow ground water settings, the model needs to be reliably calibrated for ground water contribution. Little guidance is provided in the literature concerning the manner of this contribution. In fact, the most common calibration of HSPF uses subjective parameter fitting and focuses on the attainment of statistical goodness of fit of runoff fluxes and water levels, ignoring ground water components. The goal of this research is using a different approach to calibrate HSPF with observed water table records. In this study, HSPF is applied on a small area in west-central Florida and calibrated by comparing active ground water storage to well elevation records in range land and forested land covers. The Nash-Sutcliffe efficiency and correlation coefficient computed using observed and simulated daily flows are 0.91 and 0.96 at Peace River, respectively, also with good fair results for other stations in the model domain. The study shows that improved calibration of the model can be achieved if active ground water storage and well records are compared for timing and magnitude of fluctuations. © 2010 ASCE.


Bhat S.,University of Florida | Bhat S.,Environmental Consulting and Technology Inc. | Jacobs J.M.,University of New Hampshire | Bryant M.L.,University of Florida
Water, Air, and Soil Pollution | Year: 2011

In order to investigate the effects of canopy-dependent processes on throughfall chemistry, comparative studies on the chemical composition of throughfall were carried out in five characteristic forest types of the southeastern United States within Fort Benning Military Installation from January 2002 to August 2003. The concentrations and fluxes of and total organic carbon (TOC), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) were determined in rainfall and throughfall. Seasonal variations in chemical fluxes were also evaluated. Throughfall concentrations of TOC, TKN, and TP in matured pine stand were higher than in rainfall and other forest stands. Throughfall nutrient concentrations in wetland were lowest as compared to rainfall as well as hardwood, mixed, plantation, and pine stands. The average TOC, TKN, and TP concentrations in the matured pine stand were 17. 2, 0.74, and 0.057 mg/L, respectively. In wetland stands, average concentrations of TOC, TKN, and TP were 4. 0, 0.54, and 0.034 mg/L, respectively. Hardwood stand had the lowest TKN concentration of 0.53 mg/L. Nutrient fluxes were generally higher during the dormant season (November-April) as compared to the growing season (May-October). The highest and lowest TOC fluxes during dormant season were contributed from pine stand (801.7 g/ha) and wetland stand (186.2 g/ha), respectively. Rainfall was the major contributor of TKN fluxes in growing season (32.3 g/ha) as well as in dormant season (34.1 g/ha). Similarly, highest TP flux was produced in mixed stand (2.7 g/ha) during the dormant season. Enrichment ratios of nutrients reveal that, in general, forest stands used up nutrients during growing season and washed off during the dormant season. © Springer Science+Business Media B.V. 2010.


Zeng J.,South Florida Water Management District | Zhang L.,South Florida Water Management District | Deaton L.,South Florida Water Management District | Damisse E.,South Florida Water Management District | And 2 more authors.
World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress | Year: 2011

Lack of field flow measurements is an obstacle to flow rating at structures, especially for complex hydraulic structures, specifically when they experience extremely high or low flow conditions. This paper investigates the feasibility of using the Computational Fluid Dynamic (CFD) simulated flow data for spillway and culvert rating where the field-measured flow data is inadequate or unavailable. Compared to field-measured flow, the CFD-computed flow data has proven to be accurate and reliable for both ogee spillways and box culverts flow rating. This paper also presents an example of applying CFD-computed discharge data to improve rating for a complex hydraulic structure without field flow measurements. This study demonstrates that CFD simulations are able to offer cost-effective supplement to the field measurements for flow rating at the prototype spillway, culvert and complex hydraulic structure. © 2011 ASCE.

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