Green Technologies and Sensor Networks for BMP Evaluation in Stormwater Retention Ponds and Wetlands.

The aim of this thesis is to examine and develop new techniques in stormwater Best Management Practices (BMP) for nutrient and erosion reduction and monitoring by incorporation of low impact green technologies and sensor networks. Previous research has found excessive nutrient loading of nitrogen and phosphorus species from urban stormwater runoff can lead to ecological degradation and eutrophication of receiving lakes and rivers (Fareed and Abid, 2005). In response, the Florida Department of Environmental Protection (FDEP) has set forth reduction goals as established in Total Maximum Daily Load (TMDL) reports to reduce nutrient loading and restore, or maintain, Florida water bodies to reasonable conditions. Often times current stormwater management practices are not sufficient to attain these goals and further improvements in system design are required. In order to reach these goals, affordable technologies designed for both nutrient reduction and monitoring of system performance to deepen and improve our understanding of stormwater processes are required. Firstly this thesis examines the performance of three types of continuous-cycle Media Bed Reactors (MBRs) using Bio-activated Adsorptive Media (BAM) for nutrient reduction in three retention ponds located throughout the Central Florida region. Chapter 2 examines the use of a Sloped and Horizontal MBRs arranged in a baffling configuration, whereas Chapter 3 examines the field performance of a Floating MBR arranged in an upflow configuration. Each MBR was analyzed for performance in reducing total phosphorus, soluble reactive phosphorus, total nitrogen, organic nitrogen, ammonia, nitrates + nitrites, turbidity and chlorophyll a species as measured from the influent to effluent ends of the MBR. The results of the experiments indicate that MBRs may be combined with retention ponds to provide green technology alternatives for inter-event treatment of nutrient species in urban stormwater runoff by use of recyclable sorption media and solar powered submersible pumps. Secondly the thesis focusses on three new devices for BMP monitoring which may be integrated into wireless networks, including a Groundwater Variable Probe (GVP) for velocity, hydraulic conductivity and dispersion measurements in a retention pond bank (Chapter 4), an affordable Wireless Automated Sampling Network (WASN) for sampling and analysis of nutrient flux gradients in retention ponds (Chapter 5), and finally an Arc-Type Automated Pulse Tracer Velocimeter (APTV) for low velocity and direction surface water measurements in retention ponds and constructed wetlands (Chapter 6). The GVP was integrated with other environmental sensing probes to create a remote sensing station, capable of real-time data analysis of sub-surface conditions including soil moisture, water table stage. Such abilities, when synced with user control capabilities, may help to increase methods of monitoring for applications including erosion control, bank stability predictions, monitoring of groundwater pollutant plume migration, and establishing hydraulic residence times through subsurface BMPs such as permeable reactive barriers. Advancement of this technology may be used by establishing additional sub-stations, thereby creating sensing networks covering broader areas on the kilometer scale. Two methods for velocity calculation were developed for the GVP for low flow (Pe \u3c 0.2) and high flow (Pe \u3e 0.6) conditions. The GVP was found to operate from a 26-505 cmd-1 range in the laboratory to within ±26% of expected velocities for high-flow conditions and effectively measure directional flow angles to within ±14° of expected. Hydraulic conductivity measurements made by the GVP were confirmed to within ±12% as compared to laboratory measurements. The GVP was found capable of measuring the dispersion coefficient in the laboratory, however turbulent interferences caused during injection was found to occur. Further advancement of the technology may be merited to improve dispersion coefficient measurements. Automated water sampling can provide valuable information of the spatial and temporal distribution of pollutant loading in surface water environments. This ability is expanded with the development of the WASN, providing an affordable, ease-of-use method compared to conventional automated water samplers currently on the market. The WASN was found to effectively operate by text activation via GSM cellular networks to an activation module. Propagation of the signal was distributed to collection units via XBee modules operating on point-to-point star communication using an IEEE 802.15.4 protocol. Signal communications effectively transmitted in the field during a storm event to within a range of 200 feet and collected 50 ±4 ml samples at synced timed increments. A tracer study confirmed that no mixing of samples occurs when a factor of safety of 2 is applied to flush times. This technology provides similar abilities to current market devices at down to 10% of the cost, thereby allowing much more sampling locations for a similar budget. The Arc-Type APTV is useful in establishing both low range horizontal velocity fields and expanding low range velocity measurements below detection ranges of mechanical velocity meters. Installation of a field station showed system functionality, which may be integrated with other environmental sensing probes for surface water testing. This may assist in nutrient distribution analysis and understanding the complex behavior of hydraulic retention times within wetland systems. The device was found to work effectively in both lab and field environments from a 0.02 – 5.0 cms-1 range and measure velocity within approximately ±10% of an acoustic Doppler velocimeter and within an average of ±10° of directional measurements. A drop in accuracy was measured for velocity ranges \u3e 4.5 cms-1. The field station operated on 3G CDMA cellular network two-way communication by installation of a Raven cellular modem. Use of LoggerNet software allowed control and data acquisition from anywhere with an internet connection. This thesis also introduces brief discussions on expanding these point measurement technologies into sensing networks. Installation of sub-stations with communication protocols to one central master node station may broaden the sensing system into much larger kilometer-scale ranges, thus allowing large spatial analysis of environmental conditions. Such an integration into controllable sensing networks may help bridge the gap and add calibration and verification abilities between fine-resolution point measurements and large scale technologies such as Electrical Resistivity Tomography and satellite remote sensing. Furthermore, application of sensing networks may assist in calibration and verification of surface and groundwater models such as ModFlow, SVFlux and FEHM

Low Flow Regime Measurements With An Automatic Pulse Tracer Velocimeter (Aptv) In Heterogeneous Aquatic Environments

Cost-effective velocity measurements at lab and field scales are required for understanding and modeling the flow characteristics in aquatic environments such as constructed wetlands, coastal marshes, lakes and reservoirs. This paper presents a new measurement device-the automatic pulse tracer velocimeter (APTV) that is designed to measure water velocities for low flow regimes (0.2-5.0cms-1) in heterogeneous aquatic environments using NaCl pulse tracer measurements. Hydraulic data collected in a laboratory-scale flume and field-scale constructed wetland were analyzed to determine velocity, directional flow and dispersion coefficients measured by using a cross-type and arc-type APTV. Acoustic Doppler velocimeters (ADVs) were used to collect calibration measurements in a hydraulic flume to gain fundamental understanding in support of field experiments. To test the effects of vegetation, four scenarios of laboratory-scale tests having both submerged and emergent artificial vegetation were conducted in a flume including; (1) no artificial vegetation (NAV), (2) submerged artificial vegetation (SAV) (3) emergent artificial vegetation (EAV), and (4) mix artificial vegetation (MAV). Directional flow detection and simulated storm event flow tests were conducted using an arc-type APTV data in the flume to gain perspectives of APTV performance in variable flow conditions. Cross-type APTV pulse data were eventually analyzed to determine dispersion coefficients based on the tracer curves. Finally APTVs were tested alongside an ADV for a three-day duration in a constructed wetland nearby the Everglades, Florida. Operating advantages of the APTV compared to other similar sensors were summarized in the end to enhance the application potential. Results indicate that APTVs are ideal device for affordable measurements of velocities in a 0.2-4.5cms-1 range with the prediction of both velocity field, direction and dispersion coefficients, and capable of autonomous deployment and control in a sensor network

Flow Measurements With A Cross-Type Automatic Pulse Tracer Velocimeter (Aptv) In Heterogeneous Environments

Understanding the surface water velocities of a surface water system is important for studying the fate and transport of nutrients and contaminants in heterogeneous aquatic environments. This paper presents a new sensor for measuring low range water velocities and this innovative new device is named the Automatic Pulse Tracer Velocimeter (APTV). The APTV operates by measuring the time for a pulse of saline solution to travel a fixed distance from an injection port to a set of copper wire detectors. The detectors consistently measure the change in conductivity and establish a tracer curve of the passing pulse. Using an empirical method velocity components are derived from the tracer curves. A calibration curve is then developed by comparison of the APTV with a Sontek Flow Tracker Acoustic Doppler Velocimeter in a hydraulic flume. The calibrated APTV velocities are then verified by comparison with a Nortek ADV in both a hydraulic flume and field environment. Both lab and field measurements indicate that APTV technology is capable of measuring flow velocities as low as 0.2 cm/sec and as high as 6.0 cm/sec. The sensor network may host a few sensors to collect velocity profile horizontally and vertically. © 2014 IEEE

Low flow regime measurements with an automatic pulse tracer velocimeter (APTV) in heterogeneous aquatic environments

Cost-effective velocity measurements at lab and field scales are required for understanding and modeling the flow characteristics in aquatic environments such as constructed wetlands, coastal marshes, lakes and reservoirs. This paper presents a new measurement device-the automatic pulse tracer velocimeter (APTV) that is designed to measure water velocities for low flow regimes (0.2-5.0 cm s(-1)) in heterogeneous aquatic environments using NaCl pulse tracer measurements. Hydraulic data collected in a laboratory-scale flume and field-scale constructed wetland were analyzed to determine velocity, directional flow and dispersion coefficients measured by using a cross-type and arc-type APTV. Acoustic Doppler velocimeters (ADVs) were used to collect calibration measurements in a hydraulic flume to gain fundamental understanding in support of field experiments. To test the effects of vegetation, four scenarios of laboratory-scale tests having both submerged and emergent artificial vegetation were conducted in a flume including; (1) no artificial vegetation (NAV), (2) submerged artificial vegetation (SAV) (3) emergent artificial vegetation (EAV), and (4) mix artificial vegetation (MAV). Directional flow detection and simulated storm event flow tests were conducted using an arc-type APTV data in the flume to gain perspectives of APTV performance in variable flow conditions. Cross-type APTV pulse data were eventually analyzed to determine dispersion coefficients based on the tracer curves. Finally APTVs were tested alongside an ADV for a three-day duration in a constructed wetland nearby the Everglades, Florida. Operating advantages of the APTV compared to other similar sensors were summarized in the end to enhance the application potential. Results indicate that APTVs are ideal device for affordable measurements of velocities in a 02-4.5 cm s(-1) with the prediction of both velocity field, direction and dispersion coefficients, and capable of autonomous deployment and control in a sensor network. (C) 2015 Elsevier Ltd. All rights reserved

Flow measurements with a cross-type Automatic Pulse Tracer Velocimeter (APTV) in heterogeneous environments

Understanding the surface water velocities of a surface water system is important for studying the fate and transport of nutrients and contaminants in heterogeneous aquatic environments. This paper presents a new sensor for measuring low range water velocities and this innovative new device is named the Automatic Pulse Tracer Velocimeter (APTV). The APTV operates by measuring the time for a pulse of saline solution to travel a fixed distance from an injection port to a set of copper wire detectors. The detectors consistently measure the change in conductivity and establish a tracer curve of the passing pulse. Using an empirical method velocity components are derived from the tracer curves. A calibration curve is then developed by comparison of the APTV with a Sontek Flow Tracker Acoustic Doppler Velocimeter in a hydraulic flume. The calibrated APTV velocities are then verified by comparison with a Nortek ADV in both a hydraulic flume and field environment. Both lab and field measurements indicate that APTV technology is capable of measuring flow velocities as low as 0.2 cm/sec and as high as 6.0 cm/sec. The sensor network may host a few sensors to collect velocity profile horizontally and vertically. © 2014 IEEE

Design of an endoscopic 3-D Particle-Tracking Velocimetry system and its application in flow measurements within a gravel layer

In this thesis a novel method for 3-D flow measurements within a permeable gravel layer is developed. Two fiberoptic endoscopes are used in a stereoscopic arrangement to acquire image sequences of the flow field within a single gravel pore. The images are processed by a 3-D Particle-Tracking Velocimetry (3-D PTV) algorithm, which yields the three-dimensional reconstruction of Lagrangian particle trajectories. The underlying image processing algorithms are significantly enhanced and adapted to the special conditions of endoscopic imagery. This includes methods for image preprocessing, robust camera calibration, image segmentation and particle-tracking. After a performance and accuracy analysis, the measurement technique is applied in extensive systematic investigations of the flow within a gravel layer in an experimental flume at the Federal Waterways Engineering and Research Institute in Karlsruhe. In addition to measurements of the pore flow within three gravel pores, an extended experimental setup enables the simultaneous observation of the near-bed 3-D flow field in the turbulent open-channel flow above the gravel layer and of grain motions in a sand layer beneath the gravel layer. The interaction of the free surface flow and the pore flow can be analyzed for the first time with a high temporal and spatial resolution. The experiments are part of a research project initiated by an international cooperation called Filter and Erosion Research Club (FERC). The longterm goal of this project is to quantify the influence of turbulent velocity and pressure fluctuations on the bed stability of waterways. The obtained experimental data provide new insight into the damping behaviour of a gravel bed and can be used for comparison with numerical, analytical and phenomenological models