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Final Report: Beneficial Use Of Urban Runoff For Wetland Enhancement
EPA Grant Number: R825427C010Subproject: this is subproject number 010 , established and managed by the Center Director under grant R825427
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Urban Waste Management and Research Center (University New Orleans)
Center Director: McManis, Kenneth
Title: Beneficial Use Of Urban Runoff For Wetland Enhancement
Investigators: Cothren, Gianna M. , Hannoura, A. P. , Nyman, J. A.
Institution: University of New Orleans
EPA Project Officer:
Project Period: July 1, 1998 through July 1, 2000
RFA: Urban Waste Management & Research Center (1998)
Research Category: Targeted Research
Description:
Objective:The concept of using natural wetlands to reduce nutrient loading to receiving waters is consistent with national efforts to reduce eutrophication in estuaries. The concept of restoring freshwater inflows to estuarine wetlands, artificially isolated from historic freshwater inflows, is also consistent with national efforts to restore critical estuarine wildlife and fisheries habitat. Simultaneously mitigating nutrient loading to estuarine waters and losses of historic freshwater inflows to estuarine wetlands is central to the Center's mission that includes research in seeking alternative methods for managing wastes.
The Coastal Wetland Planning, Protection and Restoration Act (CWPPRA), approved by the U.S. Congress in 1990 provides support for constructing and monitoring projects aimed at restoring coastal marshes nationwide. In Louisiana, a project utilizing urban runoff to restore freshwater inflow to an estuarine marsh was approved (LDNR, 1995). CWPPRA uses aerial photography, habitat mapping, spatial analysis, vegetation sampling, and water chemistry sampling to determine the effects of increasing urban runoff on environmental quality in the marsh. Simultaneous determination of the effectiveness of the marsh at treating the urban storm water runoff is needed to guide urban wastewater managers, but is beyond the scope of CWPPRA's monitoring activities. Design and maintenance of wetland systems for treating urban runoff depends upon sediment and nutrient fluxes through the system. Nutrient source/sink rates in a wetland system will lead to potential loading rates obtainable for treatment of urban runoff and wetland restoration. Types of data needed to better understand the role of wetlands in nutrient dynamics in general include nutrient input sources and rates, and nutrient sinks and rates, but are unavailable.
The objectives of this research are to establish a mass balance for the discharging of urban runoff, establish nutrient fluxes in a naturally occurring estuarine wetland, and to establish nutrient and sediment storage rates in a naturally occurring estuarine wetland receiving urban runoff. Water discharge, nutrient flux, and long-term storage rates of nutrients and sediments for the Fritchie Marsh are to be determined. Collectively, these data will be used to demonstrate that the marsh is improving water quality, to quantify nutrient and sediment loading rates, and to quantify the long-term nutrient and sediment storage rates.
Data collection prior to construction of the CWWPRA project has been completed. The original LDNR construction date was scheduled for November 1998. Construction was placed on hold because a landowner had qualms about having his property included in the agreement. Construction was repeatedly delayed and was last expected to begin by the end of September 1999, but did not. Therefore the post project monitoring phase to complete the technical objectives of this project was never performed. Considering the construction delay problems that hindered post construction monitoring; it is premature to outline any conclusions regarding the effectiveness of the urban runoff enhancement of the Fritchie Marsh Area.
Summary/Accomplishments (Outputs/Outcomes):Field work has been conducted to monitor flow at the upstream end of the W-14 Canal and the Marsh outlet to Lake Pontchartrain. Existing bridges at these sites were used to establish permanent stations along the channel cross section. In the initial stage of the field work, channel cross sections at these sites and small cuts into the interior of the marsh were surveyed for future use in estimating the flow at each of the sites. In subsequent field trips, water surface and velocity readings at two sites were taken. In addition to the surveying of the W-14 Canal and the Salt Bayou Bridge (SBB) at Louisiana Highway 433, a small bridge at the Doubloon Branch and Highway 190 was identified.
Water surface and velocity readings at this site and limited data from the SBB site were collected. It has been found that flow patterns in and around the Fritchie Marsh is complicated by a number of meteorological variables controlling the flow. Flow measurements on June 30th, 1999 and July 7th, 1999 indicate that flow in the W-14 Canal is strongly correlated with rainfall events and wind. It has also been found that flow at the SBB is mostly due to tidal fluctuations. Observed velocities at the SBB during the two field trips were too small to measure. There was no flow through the Doubloon Branch and Highway 190 Bridge.
The USGS field office in Baton Rouge, LA, was contacted in order to verify the outcome of field measurements of the flow taken on the above dates. It was found that similar findings were concluded by the USGS on three different dates during 1983, i.e., April 6, August 26, and October 25. USGS findings also indicated that the only significant inflow to the Fritchie Marsh systems occurs during flooding events of the Pearl River. During the flood event of April 6, 1983, flood of record, flow over the U.S. Highway was estimated as 8,447 cfs and 2,530 cfs through the Doubloon Branch and Highway 190 bridge.
Information gathered from literature and a site investigation revealed that surface inflow to the Fritchie Marsh is from precipitation, the W-14 canal, and Salt Bayou. Surface outflows are from Salt Bayou and evaporation. Salt Bayou behavior is dependent on tidal cycles, Lake Pontchartrain elevations, and West Pearl River flood flows. The source of the precipitation data is the National Oceanic and Atmospheric Administration (NOAA). The closest weather station to the Fritchie Marsh is in the southern region of Slidell, LA. The data were sorted on an hourly basis for representation at the storm event duration level with the rest of the hours having zero precipitation. Evapotranspiration is estimated from published pan evaporation from the monthly data of the Louisiana Office of State Climatology, Southern Regional Climate Center. It was assumed that evapotranspiration from the saturated wetland is equivalent to that open surface water. Tidal amplitude in the Fritchie Marsh is less than 2 ft. During a rising tide, water flows into the Fritchie Marsh and the overflow water spreads back downstream over the marsh surface. On falling tides, the flows are reversed. At low tides water drains from the adjacent wetlands into the open water of the Marsh. The water budget calculation was performed using a spreadsheet program. The net flow was calculated on an hourly basis for a three month period from October 15, 1998 to January 31, 1999
The nutrient component of the study involved quantifying long-term nutrient storage rates in Fritchie Marsh under existing nutrient loading conditions. Cores were sectioned, weighed, oven-dried, weighed, and crushed. Bulk density of each section was calculated. Marsh vertical accretion since 1963 was determined with the 137Cs dating technique (DeLaune et al. 1978). Activity of 137Cs was determined with an Ortec GMX series Gamma-x-high purity, N-type germanium coaxial photon detector system. The gross accumulation rate; i.e., the accumulation of mineral sediments as well as organic matter, was calculated for each core from the bulk density of all soil samples overlying the 1963 marsh surface. Nitrogen, carbon, and phosphorus content of all soil overlying the 1963 marsh surface will be determined following acid digestion as described above.
Bulk density averaged 0.18 g/cm3 at the northern site and 0.13 g/cm3 at the southern site. The greater bulk density at the northern site suggests that more material is introduced into Fritchie marsh from the W-14 Canal than from Lake Pontchartrain. However, examination of density profiles with depth suggests that additional material at the northern site accumulated in soil that was formed decades ago. Thus, the northern and southern sites currently appear to be storing more similar amounts of material than the average bulk density suggests.
Accretion in Fritchie Marsh averaged 0.63 cm/yr. This is slightly less than the average for brackish marshes in the Mississippi River Deltaic Plain (0.72 cm/yr; Nyman et al. 1990). The more rapid average accretion in the entire Mississippi River Deltaic Plain than in the Fritchie Marsh probably results from the more rapid subsidence rate in the Mississippi River Deltaic Plain (approximately 1.0 cm/yr; Penland et al. 1990). Accretion rates within sites were almost identical but the two sites differed greatly (Figures 9,10). Accretion at the northern site averaged 0.53 cm/yr; accretion at the southern site averaged 0.84 cm/yr. Accretion at the northern site is similar to estimates of subsidence on the northern shore of Lake Pontchartrain, which is estimated at 0.45 cm/yr (Penland and Ramsey 1990). However, it is difficult to reconcile the rapid accretion at the southern site with the slow subsidence reported by Penland and Ramsey (1990). It is also unusual for accretion rates to vary so much within such a small area (e.g., Nyman et al. 1990, Nyman et al. 1993). The large difference between northern and southern sites suggests that a shallow, active fault runs through Fritchie Marsh. Such faults are common in coastal Louisiana in general in and around Lake Pontchartrain. Lopez (1991) examined seismic data and reinterpreted the location of Baton Rouge/Denham Springs fault system and concluded that the fault lay farther south than previously believed and positioned it such that it would bisect the Fritchie Marsh. Our findings support Lopez's (1991) conclusions regarding the position of that fault system. Lopez (1991) also concluded that the fault system was active and responsible for a 6-inch offset on the State Highway Bridge 11 crossing eastern Lake Pontchartrain. The tremendous difference in accretion rates between the northern and southern sites that we observed also support Lopez's (1991) conclusion that the fault system is active, although different faults within the fault system would be required to produce offset in accretion in the Fritchie Marsh and the offset in the highway bridge. While this active fault may contribute greatly to wetland loss in the Fritchie Marsh, it also increases the potential for burial of nutrients in the marsh.
To determine the rate at which material is being stored in marsh soil at the two sites, the bulk density estimates were combined with the vertical accretion estimates. Storage averaged 1.3 kg m-2 yr-1 at the northern site; storage averaged 1.6 kg m-2 yr-1 at the southern site. The faster storage rate at the southern site is probably related to the more rapid subsidence induced at the southern site by the fault. On average, the Fritchie marsh annually stores 5,872 kg/acre. Extrapolated to the entire area; it appears that the 1,040 acre Fritchie Marsh restoration site stores slightly over 6 million kg of material annually. Some of this material is organic carbon that is produced in the marsh but the associated nutrients and sediments otherwise would be discharged into Lake Pontchartrain
The objectives establishing a pre construction mass balance for the discharging of urban runoff and to establishing nutrient and sediment storage rates in a naturally occurring estuarine wetland receiving urban runoff have been met. A spreadsheet program was developed to perform pre-construction water budget calculations. The net flow was calculated on an hourly basis for a three month period from October through January, 1999. The hourly change in volume and depth was calculated using the net flows and total area Fritchie Marsh area. Hourly change in salinity was calculated and a mass balance was performed. This same program lends itself to the calculation of the nutrient flux once pre and post construction water quality data become available.
Bulk density averaged 0.18 g/cm3 at the northern site and 0.13 g/cm3 at the southern site. The greater bulk density at the northern site suggests that more material is introduced into Fritchie marsh from the W-14 Canal than from Lake Pontchartrain. However, examination of density profiles with depth suggests that additional material at the northern site accumulated in soil that was formed decades ago. Thus, the northern and southern sites currently appear to be storing more similar amounts of material than the average bulk density suggests.
Accretion in Fritchie Marsh averaged 0.63 cm/yr with the northern site accretion averaging 0.53 cm/yr and the accretion at the southern site averaging 0.84 cm/yr. This difference between northern and southern sites suggests that a shallow, active fault runs through Fritchie Marsh. Such faults are common in coastal Louisiana in general and around Lake Pontchartrain. The bulk density estimates were combined with the vertical accretion estimates to determine the rate at which material is being stored in marsh soil at the two sites. Storage averaged 1.3 kg m-2 yr-1 at the northern site and 1.6 kg m-2 yr-1 at the southern site which is probably related to the more rapid subsidence at the southern site induced by the fault. The Fritchie marsh stores an annual average of 5,872 kg/acre. Extrapolated over the entire Fritchie Marsh area, it appears that this site stores slightly over 6 million kg of material annually.
Journal Articles:No journal articles submitted with this report: View all 2 publications for this subproject
Supplemental Keywords:wetland water budget, nutrient storage rates, accretion rates. , Geographic Area, Scientific Discipline, Waste, Analytical Chemistry, Ecological Risk Assessment, Municipal, Environmental Chemistry, Ecology and Ecosystems, State, constructed wetlands, waste minimization, urban waste, groundwater quality, New Orleans (NO), urban runoff, storm drainage systems, technology transfer, waste management, municipal waste, outreach
Progress and Final Reports:
Original Abstract
Main Center Abstract and Reports:
R825427 Urban Waste Management and Research Center (University New Orleans)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825427C001 Comprehensive Evaluation of The Dual Trickling Filter Solids Contact Process
R825427C002 Issues Involving the Vertical Expansion of Landfills
R825427C003 Deep Foundations on Brownfields Sites
R825427C004 Ambient Particulate Concentration Model for Traffic Intersections
R825427C005 Effectiveness of Rehabilitation Approaches for I/I Reduction
R825427C006 Urban Solid Waste Management Videos
R825427C007 UWMRC Community Outreach Multimedia Exhibit
R825427C008 Including New Technology into the Investigation of Inappropriate Pollutant Entries into Storm Drainage Systems - A User's Guide
R825427C009 Investigation of Hydraulic Characteristics and Alternative Model Development of Subsurface Flow Constructed Wetlands
R825427C010 Beneficial Use Of Urban Runoff For Wetland Enhancement
R825427C011 Urban Storm and Waste Water Outfall Modeling
R827933C001 Development of a Model Sediment Control Ordinance for Louisisana
R827933C002 Inappropriate Discharge to Stormwater Drainage (Demonstration Project)
R827933C003 Alternate Liner Evaluation Model
R827933C004 LA DNR - DEQ - Regional Waste Management
R827933C005 Landfill Design Specifications
R827933C006 Geosynthetic Clay Liners as Alternative Barrier Systems
R827933C007 Used Tire Monofill
R827933C008 A Comparison of Upflow Anaerobic Sludge Bed (USAB) and the Anaerobic Biofilm Fluidized Bed Reactor (ABFBR) for the Treatment of Municipal Wastewater
R827933C009 Integrated Environmental Management Plan for Shipbuilding Facilities
R827933C010 Nicaragua
R827933C011 Louisiana Environmental Education and Resource Program
R827933C012 Costa Rica - Costa Rican Initiative
R827933C013 Evaluation of Cr(VI) Exposure Assessment in the Shipbuilding Industry
R827933C014 LaTAP, Louisiana Technical Assistance Program: Pollution Prevention for Small Businesses
R827933C015 Louisiana Environmental Leadership Pollution Prevention Program
R827933C016 Inexpensive Non-Toxic Pigment Substitute for Chromium in Primer for Aluminum Sibstrate
R827933C017 China - Innovative Waste Composting Plan for the City of Benxi, People's Rupublic of China
R827933C018 Institutional Control in Brownfields Redevelopment: A Methodology for Community Participation and Sustainability
R827933C019 Physico-Chemical Assessment for Treatment of Storm Water From Impervious Urban Watersheds Typical of the Gulf Coast
R827933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
R827933C021 Characterizing Moisture Content Within Landfills
R827933C022 Bioreactor Landfill Moisture Management
R827933C023 Urban Water Issues: A Video Series
R827933C024 Water Quality Modeling in Urban Storm Water Systems
R827933C025 The Development of a Web Based Instruction (WBI) Program for the UWMRC User's Guide (Investigation of Inappropriate Pollutant Entries Into Storm Drainage Systems)
R827933C027 Legal Issues of SSO's: Private Property Sources and Non-NPDES Entities
R827933C028 Brownfields Issues: A Video Series
R827933C029 Facultative Landfill Bioreactors (FLB): A Pilot-Scale Study of Waste Stabilization, Landfill Gas Emissions, Leachate Treatment, and Landfill Geotechnical Properties
R827933C030 Advances in Municipal Wastewater Treatment
R827933C031 Design Criteria for Sanitary Sewer System Rehabilitation
R827933C032 Deep Foundations in Brownfield Areas: Continuing Investigation
R827933C033 Gradation-Based Transport, Kinetics, Coagulation, and Flocculation of Urban Watershed Rainfall-Runoff Particulate Matter
R827933C034 Leaching and Stabilization of Solid-Phase Residuals Separated by Storm Water BMPs Capturing Urban Runoff Impacted by Transportation Activities and Infrastructure
R827933C035 Fate of Pathogens in Storm Water Runoff
R87933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region