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PILOT STUDY OF NUTRIENT LOADING IN A WET DETENTION LAKE
Title
PILOT STUDY OF NUTRIENT LOADING IN A WET DETENTION LAKE.
Creator
Gurr, Eric, Nnadi, Fidelia, University of Central Florida
Abstract / Description
Florida is surrounded by water, and its many internal lakes and rivers have long been recognized for their excellent fishing and boating. This notoriety draws land developers to the lake shores to establish residential and commercial infrastructure. This land development brings with it flood plain alteration, water level stabilization, and increased nutrients which cause adverse impacts to our lakes. In response, the United States Environmental Protection Agency (EPA) passed the Federal Clean...
Show moreFlorida is surrounded by water, and its many internal lakes and rivers have long been recognized for their excellent fishing and boating. This notoriety draws land developers to the lake shores to establish residential and commercial infrastructure. This land development brings with it flood plain alteration, water level stabilization, and increased nutrients which cause adverse impacts to our lakes. In response, the United States Environmental Protection Agency (EPA) passed the Federal Clean Water Act (CWA) in 1972 which set the framework for the water quality standards for the entire United States. As a result of the CWA many point sources were eliminated, but in the process it became apparent that nonpoint source loads represented even more of a threat. To further study the physical and chemical characteristics of urban runoff the Nationwide Urban Runoff Program (NURP) was established in 1978. This research lead to a series of management options, named Best Management Practices (BMPs) which proposed various structural and non-structural methods to reduce nutrient loads. But the research and data collection on the effectiveness of these systems to remove nutrients is in its infancy. The main objective of this study was to generate accurate and effective water quality and water quantity data that future stormwater management decisions can be based upon. More specific, this study established automatic monitoring sites throughout the City of Kissimmee, Florida to determine the pollutant loadings into the tributaries of Lake Tohopekaliga. These monitoring sites are located such that inflows from outside the city limits can be isolated and external pollutant loads quantified. Also, additional internal monitoring sites were established to determine the pollutant loads of internal sections of the city. Data from these internal monitoring sites will also be used to determine the variable pollutant removal efficiencies and hydraulic fluctuations of natural, irregular riverine systems. The secondary objective of this study was to perform a pilot study using the discrete grab samples in tandem with the continuous hydraulic and hydrologic data from the monitoring stations. An existing lake within the project limits was chosen for the pilot study area. Monitoring stations are located at the influent and effluent sections of the lake which provided data on the hydraulic and hydrologic parameters. The pilot study determined the nutrient loads to and from the lake and checked for any seasonal variations in pollutant loading or removal efficiencies. For the purpose of this pilot study, only total nitrogen and total phosphorous were examined for two monitoring sites. The nutrient removal efficiency was performed using both the event mean concentration method and the summation of loads method to check for seasonal variation. There were no storm event concentrations available for used in this analysis, however, there were 25 discrete grab samples collected on a bi-monthly basis over a twelve month period. This data was used with corresponding five-minute rainfall and flow data from both the inflow and outflow points. The results of this study did not reveal any seasonal variation in the nutrient concentrations either flowing into or out from the lake. Although there were some relatively lower values in late spring, the concentration levels of total nitrogen did not seem to vary significantly from its mean value of 0.90 mg/l throughout the year. The concentration levels of total phosphorus did range from 0.02 mg/l to 0.48 mg/l, but not in relation to either season or flow volume fluctuations. The lake showed no net removals of total nitrogen and was actually found to be releasing total phosphorus to the downstream receiving waters. The findings of this study are limited due to the fact that the period of pilot study was only for twelve months and there were no rainfall events used in the analysis. Rainfall events are typically high sources of nutrient loads to a lake. The lower efficiencies were probably due to missing the actual higher nutrient load concentrations during the rainfall event. However, even considering the lack of event data, the nutrient removal efficiency for the pond was still low. This analysis did serve well as a basis for performing future analysis once additional data, including rainfall events, has been collected.
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Date Issued
2007
Identifier
CFE0001912, ucf:47474
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001912
Low Impact Development Analysis and Comparative Assessment of Wet Detention Ponds with Floating Treatment Wetlands
Title
Low Impact Development Analysis and Comparative Assessment of Wet Detention Ponds with Floating Treatment Wetlands.
Creator
Hartshorn, Nicholas, Chang, Ni-bin, Kibler, Kelly, Wanielista, Martin, University of Central Florida
Abstract / Description
The aim of this thesis is to examine, develop, and assess innovative best management practices (BMPs) in stormwater management for pollutant reduction, flood control, and environmental sustainability. Previous research has clearly shown that urban stormwater runoff quickly transports pathogens, metals, sediment, and chemical pollutants to receiving waterbodies, resulting in the degradation of receiving waters and disruption of ecological networks. In response to this growing concern,...
Show moreThe aim of this thesis is to examine, develop, and assess innovative best management practices (BMPs) in stormwater management for pollutant reduction, flood control, and environmental sustainability. Previous research has clearly shown that urban stormwater runoff quickly transports pathogens, metals, sediment, and chemical pollutants to receiving waterbodies, resulting in the degradation of receiving waters and disruption of ecological networks. In response to this growing concern, regulatory agencies, such as the Environmental Protection Agency (EPA) and the Florida Department of Environmental Protection (FDEP), have set forth regulations aimed at protecting and restoring waterbodies. These regulations include numeric nutrient criteria (NNC) and total maximum daily loads (TMDLs), which enable effective monitoring of a waterbody with regard to nitrogen and phosphorus pollution and help to restore waters not attaining their designated uses. Currently, many stormwater management systems do not provide sufficient nutrient reduction to meet growing regulations; thus, there is a clear need to develop additional BMPs to enhance nutrient reduction.Firstly, this thesis provides an overview of BMPs used in urban regions across the globe to create networks of low impact development (LID), with a focus on policy analysis. Chapter 2 examines the regulatory policies in areas of the United States, Europe, Asia, and Australia from a federal, state, to local perspective in order to pinpoint what policies are supporting the shift from gray cities to green cities. Gray cities are cities comprised mainly of impervious surfaces, with little regard to the ecological health and hydrologic characteristics of the area. Green cities utilize LID to mimic pre-development hydrologic and ecological characteristics, resulting in a city that is both environmentally sustainable and offers many ecosystem services. The results of the global policy analysis identified the policies and other factors, such as funding and public involvement, necessary to facilitate the shift from gray cities to green cities and support the widespread implementation of LID.Secondly, this thesis provides a comparative analysis of three stormwater wet detention ponds, which all contained floating treatment wetlands (FTWs). FTWs are a new BMP, used to enhance nutrient reduction rates in stormwater wet detention ponds. FTWs are a manmade ecosystem, utilizing plants that grow on interlocking floating foam mats, that mimics natural wetlands. Both episodic (storm event) and routine (non-storm event) sampling campaigns were carried out at the three stormwater wet detention ponds located in Gainesville, Ruskin, and Orlando, Florida. The comparative analysis of the three stormwater wet detention ponds was based on two perspectives. The fist analysis, found in Chapter 2, focuses solely on the nutrient reduction potential of FTWs and how the installation of FTWs can be used to improve nutrient reduction rates in stormwater wet detention ponds. The second analysis, found in Chapter 3, focuses on the interaction between nutrients, microcystin, and chlorophyll-a in the stormwater wet detention ponds before and after installation of the FTWs. These two studies provide a holistic understanding of the environmental and ecological aspects of utilizing FTWs as a BMP in stormwater management. FTWs were found to have a significant impact on nutrient reduction rates in the three stormwater wet detention ponds, with total nitrogen (TN) reduction rates reaching 33% at the Ruskin pond during storm events and total phosphorus (TP) reduction rates reaching 71% at the Gainesville pond during storm events. Moreover, microcystin concentrations were found to have a negative correlation with nutrient concentrations, specifically total phosphorus, for both storm and non-storm events across all three ponds.
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Date Issued
2016
Identifier
CFE0006113, ucf:51206
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006113