Fox G.A.,Oklahoma State University |
Matlock E.M.,Oklahoma State University |
Guzman J.A.,Oklahoma State University |
Sahoo D.,Woolpert Inc. |
Stunkel K.B.,Oklahoma State University
Journal of Environmental Quality | Year: 2011
Vegetative filter strips (VFS) are commonly used best management practices for removing contaminants from runoff. Additional research is warranted to determine their efficiency and the most appropriate metrics for predicting fecal bacteria reductions. The objective of this research was to determine VFS effectiveness in removing Escherichia coli from runoffrelative to inflow rate, infiltration capacity, and flow concentration. This research also investigated the presence of E. coli in runofffrom clean water runon after diluted manure runon events. A laboratory-scale VFS soil box (200 cm long, 100 cm wide, 7.5% slope) was packed with a sandy loam soil. Ten constant-flow VFS experiments were conducted with and without vegetation (8-10 cm ryegrass [Lolium perenne L.]) at low (20-40 cm 3 s -1), medium (40-60 cm 3 s -1), and high (85-120 cm 3s -1) flow rates and for a full (100 cm) or concentrated (40 cm) VFS flow width to simulate a channelizing flow condition. Two runon events were investigated for each experimental condition: (i) diluted liquid swine manure runon and (ii) clean water runon 48 h afterward. Escherichia coli was used as an indicator of fecal contamination and was quantified by the most probable number (MPN) technique. No E. coli concentration reductions were observed based on peak outflow concentrations, and only small concentration reductions were observed based on outflow event mean concentrations. The E. coli mass reductions ranged from 22 to 71% and were strongly correlated to infiltration or runoffreduction (R 2 = 0.88), which was dependent on the degree of flow concentration. Little to no effect of sedimentation on E. coli transport was observed, hypothesized to be due to minimum E. coli attachment to sediment particles because the bacteria originated from manure sources. Th erefore, the design of VFS for bacteria removal should be based on the infiltration capacity in the VFS and should prevent concentrated flow, which limits total infiltration. The E. coli event mean concentrations in clean water runon experiments were between 10 and 100 MPN per 100 mL; therefore, under these conditions, VFS served as a source of residual E. coli from previous runon events. © 2011 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. Source
Medeiros S.C.,University of Central Florida |
Ali T.,American University of Sharjah |
Ali T.,University of Central Florida |
Hagen S.C.,University of Central Florida |
Raiford J.P.,Woolpert Inc.
Photogrammetric Engineering and Remote Sensing | Year: 2011
This applications paper presents the methods used to create a seamless topobathy digital terrain model (DTM) at 50-foot resolution intended to support hurricane storm surge modeling in Tampa Bay, Florida. Lidar, bathymetry, and various breakline data were integrated using the Terrain Data Set structure in ArcGIS®. The use of the Terrain Data Set structure allowed for embedding large data sets (such as lidar points) and archiving them after DTM creation while maintaining topographic analysis capabilities. The bathymetric data, natively referenced to Mean Sea Level (MSL), were converted to North American Vertical Datum of 1988 (NAVD88) using an inverse distance weighted average offset from the three nearest NOAA tidal benchmark stations; results of this conversion were within 6.1 centimeters of those produced by NOAA VDatum software in a quality control test area. This methodology can therefore be used in coastal regions of other countries. © 2011 American Society for Photogrammetry and Remote Sensing. Source
Borah D.K.,Woolpert Inc.
Hydrological Processes | Year: 2011
Currently, many watershed models are available that have various complexities, strengths, and weaknesses. The basic mathematical foundations of these mathematical models are often overlooked due to high demands on convenient applications with graphical user interfaces. Although this and other factors are important while selecting a model, the mathematical foundation should also be taken into account, as performance or efficiency and accuracy of a model depend on its simplicity or complexity. A comprehensive review of 14 storm event watershed models was conducted. Hydrologic procedures (rainfall excess, flow routing, and subsurface flow) of the models are presented and compiled. Among the procedures, flow routing has the most influence on model performances (speed and accuracy). Overland and channel flow routing procedures using different flow-governing equations, having various approximations and solved by different methods, are compared based on their relative levels of physical bases, complexities, and expected accuracies in simulating the dynamics of water flow. Models using more mathematical terms in the flow-governing equations are more physically based and expected to be more accurate than models using approximations, however, are more complex due to more intensive but approximate numerical schemes (inefficient). Models using approximate equations with analytical solutions may provide a balance between complexity and accuracy. The review and comparisons are useful to modellers, water resources managers, and researchers in understanding the basic foundations of the models and making informed selections for practical applications or further developments. Other factors such as data intensiveness, user friendliness, and resource requirements are also important considerations. © 2011 John Wiley & Sons, Ltd. Source
Russomanno D.J.,University of Memphis |
Tritenko Y.,Woolpert Inc.
Sensors | Year: 2010
A prototype Geographic Information System (GIS) framework has been developed to map, manage, and monitor sensors with respect to other geographic features, including land base and in-plant features. The GIS framework supports geographic placement and subsequent discovery, query, and tasking of sensors in a network-centric environment using Web services. The framework couples the GIS feature placement logic of sensors with an extensible ontology which captures the capabilities, properties, protocols, integrity constraints, and other parameters of interest for a large variety of sensor types. The approach is significant in that custom, GIS-based interfaces can be rapidly developed via the integration of sensors and sensor networks into applications without having detailed knowledge of the sensors' underlying device drivers by leveraging service-oriented computing infrastructure within the GIS framework. © 2010 by the authors; licensee MDPI, Basel, Switzerland. Source
Woolpert Inc. | Date: 2011-01-11
computer software program for modeling the hydrology and water quality associated with developed and undeveloped land sites and the pollutant transfer and trapping efficiency of specific management practices.