Zachary, LA, United States
Zachary, LA, United States

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Ko J.-Y.,Texas A&M University | Day J.W.,Louisiana State University | Day J.W.,Comite Resources Inc. | Lane R.L.,Louisiana State University | And 2 more authors.
Ecological Engineering | Year: 2012

Academicians and government officials have advocated incorporating ecosystem services into environmental policy-making processes. The State of Louisiana has adopted policy guidelines for using natural wetlands to assimilate nutrients in secondarily treated municipal effluent, thus utilizing ecosystem services of natural wetlands. We describe a case study for the city of Breaux Bridge, Louisiana, to discuss policy guidelines and assess ecological and financial benefits of this approach. In addition to water quality improvement, wetland assimilation provides additional ecosystem services, including increased vegetative productivity, surface accretion, and carbon sequestration. Financially, using wetland assimilation at Breaux Bridge generated an economic savings of $1.8 million in capital costs and annual savings of $72,116 for operation and maintenance costs, resulting in nearly $3 million savings over the lifetime of the project, due to its low capital expenditures and high energy efficiency, compared with a sand filtration method. When considering rapidly depleting non-renewable resources (e.g., fossil fuels) and challenging financial situations of small communities across the nation, wetland assimilation can be an important factor in designing sustainable communities. © 2011 Elsevier B.V.


Lane R.R.,LSU | Lane R.R.,Comite Resources Inc. | Day J.W.,LSU | Day J.W.,Comite Resources Inc. | And 7 more authors.
Ecological Engineering | Year: 2016

The East Joyce Wetlands (EJW) bordering northwest Lake Pontchartrain have a long history of human induced changes, such as leveeing of the Mississippi River that eliminated almost all riverine input to the area and segmentation of the east and west Joyce wetlands by the construction of a railroad, U.S. highway 51, and Interstate 55. Dredged drainage canals and associated spoil banks channel upland runoff around the wetlands. The deep canal associated with I-55 causes both rapid short-circuiting of freshwater runoff to Lake Maurepas and saltwater intrusion from Lake Pontchartrain. Increasing soil salinity has caused wide-spread loss of forested wetlands in the areas. Recently, the discharge of secondarily treated municipal effluent into the northeastern EJW as part of the Hammond wetland assimilation project has focused attention on the area (i.e., Bodker et al., 2015). In response, we carried out a number of studies at the Hammond Assimilation Wetlands (HAW) detailed in Shaffer et al. (2015), as well as a series of hydrological measurements and modeling detailed here. These data show that drainage under the railroad was minimal and most flow through the wetlands was to the southeast. Water levels in the HAW were highly variable prior to the beginning of effluent discharge in 2006, with relatively high mean water levels that did not increase substantially from 2007 through summer 2009 despite the addition of municipal effluent. Following effluent addition, surface water levels lacked the variability of the pre-discharge period and mean water levels were about 20cm higher from late 2009 until 2014 due to high rainfall in 2009, 2012, and 2013 and high effluent inflow due to significant infiltration into the city collection system. Historical net watershed inputs averaged 2.69cmyr-1 if this volume of water were spread over the 4km2 area immediately south of the effluent distribution system, compared to 0.38cmyr-1 for the effluent and 0.13cmyr-1 for direct precipitation. Salinity records from five sites in the EJW showed a gradient of increasing salinity from north to south and strong seasonality, averaging 1.9-2.1 PSU near the lake to 0.4-0.6 PSU in the northwestern EJW. Peak salinities were 4.6-5.1 PSU near the lake and 1.8 PSU in northwestern EJW. There was also a significant decrease in salinity over time. Salinity was lower beginning in 2010 coinciding with the closure of the Mississippi River Gulf Outlet, high precipitation in the fall and winter of 2009, and in 2012 and 2013, and continuing operation of the assimilation system. Proposed plans to alternate effluent discharge between east and west Joyce wetlands should increase surface water depth variability as seen prior to effluent discharge and minimize salinity intrusion in both areas. © 2015.


Day J.,Louisiana State University | Day J.,Comite Resources Inc. | Hunter R.,Comite Resources Inc. | Keim R.F.,Louisiana State University | And 7 more authors.
Ecological Engineering | Year: 2012

We investigated two adjacent wetlands in the Lake Pontchartrain basin, one of which receives periodic input of Mississippi River water and one which does not, to gain insight into how isolation from river input impacts wetland loss in the Mississippi delta. The LaBranche (LB) wetlands bordering Lake Pontchartrain are severely degraded due to saltwater intrusion, subsidence, leveeing of the river, and hydrologic alterations including partial impoundment. Directly adjacent is the Bonnet Carré (BC) spillway, a geomorphically similar area that contains healthy baldcypress swamp. The spillway carries river water to the lake during high discharge years and has been opened eleven times in 80 years, with flows as high as 9000m 3s -1. The primary hydrologic difference between the two areas is the regular input of River water to the BC wetlands while the LB wetlands are isolated from the river. The interior of the LB wetlands is also isolated from sediment originating from Lake Pontchartrain. Long-term accretion, tree growth, and elevation were measured in these two wetland areas to determine impacts of riverine input. 137Cs accretion rates in the BC wetlands were 2.6-2.7cmyr -1, compared to 0.43 and 1.4cmyr -1, respectively, in the LB wetlands in areas without and with sediment input from Lake Pontchartrain. Baldypress growth in the BC averaged about 2.3mmringwidthyr -1, compared to 1.4mmyr -1 in LB. Trees are of relatively the same age due to lack of recruitment and widespread logging. Tree height, an indicator of site quality, is about 20% less at the LB sites compared to BC, even though the trees are approximately the same ages. The average wetland elevation in the BC wetlands was about one meter with some areas higher than two meters, and was significantly higher than elevations in the LB (average sea level and 0.3m, respectively, in areas with and without input from Lake Pontchartrain). © 2012 Elsevier B.V..


Shaffer G.P.,Southeastern Louisiana University | Shaffer G.P.,Comite Resources Inc. | Shaffer G.P.,Wetland Resources LLC | Day J.W.,Comite Resources Inc. | And 8 more authors.
Ecological Engineering | Year: 2014

The City of Hammond, Louisiana began discharging secondarily-treated municipal effluent into Four Mile Marsh in the northwestern Joyce wetlands during fall of 2006. At the time discharge began, these wetlands had been isolated from virtually all freshwater inflow from the surrounding watershed for over a half century, due primarily to the construction of canals and spoil banks. Immediately following effluent discharge in 2006, there was robust growth of herbaceous vegetation. By late fall 2007, the emergent wetlands in the immediate vicinity of the effluent discharge began to decline, and within months nearly the entire marsh south of the discharge pipe had converted to open water or mudflat. By 2010, there had been substantial recovery of the marsh. A number of hypotheses have been presented to explain the degradation of the marsh to open water and mudflats, including herbivory by the introduced rodent nutria ( Myocastor coypus), excessive nutrients, reductions in above- and belowground biomass, increased soil decomposition due to high nutrients, prolonged inundation, toxicity, increased pH, and disease. Intensive field and mesocosm studies provide conclusive data that the marsh loss was primarily caused by nutria herbivory, and secondarily by waterfowl herbivory, and that recovery of the herbaceous vegetation occurred as a result of aggressive nutria control (>2000 eliminated). Marsh recovery has been most intensive near the point of discharge. Mature baldcypress growing in the area of discharge had growth rates that were five times those of trees not receiving effluent in the lower Joyce area and Maurepas swamp. Field and mesocosm studies show that nutrients increased both above- and belowground biomass and did not increase decomposition rates of herbaceous vegetation. Increased flooding due to lack of drainage from the area is hindering marsh recovery. © 2015.


Lane R.R.,Louisiana State University | Lane R.R.,Comite Resources Inc. | Huang H.,Louisiana State University | Day J.W.,Louisiana State University | And 3 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

The Bayou Boeuf Basin (BBB), a sub-basin of the Barataria Basin estuary in coastal Louisiana, consists of forested and floating wetlands receiving drainage from surrounding agricultural fields and urban watersheds. We characterized surface water quality in the BBB, and determined through hydrologic modeling if a series of levee breaks along major drainage channels would significantly improve water quality by allowing flow into surrounding wetlands. Surface water monitoring found surrounding sugarcane farm fields to be major sources of nutrient and sediment loading. Hydrological modeling indicated that levee breaks would increase N reduction from the current 21.4% to only 29.2%, which is much lower than the anticipated 90-100% removal rate. This was due to several factors, one them being dredging of main drainage channels to such a degree that water levels do not rise much above the surrounding wetland elevation even during severe storms, so only a very small fraction of the stormwater carried in the channel is exposed to wetlands. These unexpected results provide insight into an undoubtedly pervasive problem in human dominated wetland systems; that of decreased flooding during storm events due to channel deepening by dredging activities. Additional water quality management practices should be implemented at the farm field level, prior to water entering major drainage canals. © 2014.


Ibanez C.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Sharpe P.J.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Day J.W.,Louisiana State University | Day J.N.,Comite Resources Inc. | Prat N.,University of Barcelona
Wetlands | Year: 2010

The Ebro Delta in Catalonia, Spain is an ecologically and commercially important wetland system under threat from sea level rise and marsh subsidence. Our principal hypothesis was that a brackish marsh that receives inorganic sediments and fresh water amendments from the Ebro River would exhibit significantly higher rates of soil accretion, resulting in a greater resistance to subsidence and sea level rise compared to isolated salt marsh habitats with no river subsidy. Marsh sites representative of the wetland ecosystems found in the Ebro Delta were selected based on plant community type, porewater salinity, and landscape position. The results supported the research hypothesis, suggesting that a brackish marsh that receives river subsidies exhibited a significantly higher (F 3,4 = 31.6, P<0.01) rate of vertical accretion compared to more hydrologically-isolated salt marsh systems. Accretion data showed that only the riverineinfluenced brackish marsh site met the minimum predicted rate of relative sea level rise (RSLR range of 5-8 mmyr -1) for the Ebro Delta. This research provides the first quantitative record of marsh subsidence and accretion dynamics in the Ebro Delta using Surface Elevation Tables (SET), marker horizons, and 210Pb techniques, and also illustrates the importance of sediment and fresh water subsidies in deltaic environments. © Society of Wetland Scientists 2010.


Shaffer G.P.,Southeastern Louisiana University | Shaffer G.P.,Comite Resources Inc. | Shaffer G.P.,Wetland Resources LLC | Day J.W.,Comite Resources Inc. | And 8 more authors.
Water (Switzerland) | Year: 2016

The Maurepas swamp is the second largest contiguous coastal forest in Louisiana but it is highly degraded due to subsidence, near permanent flooding, nutrient starvation, nutria herbivory, and saltwater intrusion. Observed tree mortality rates at study sites in the Maurepas swamp are very high (up to 100% tree mortality in 11 years) and basal area decreased with average salinities of < 1 ppt. Habitat classification, vegetation productivity and mortality, and surface elevation changes show a clear trajectory from stagnant, nearly permanently flooded forests with broken canopy to degraded forests with sparse baldcypress and dominated by herbaceous species and open water to open water habitat for most of the Maurepas swamp without introduction of fresh water to combat saltwater intrusion and stimulate productivity and accretion. Healthy forests in the Maurepas are receiving fresh water containing nutrients and sediments from urban areas, high quality river water, or secondarily treated municipal effluent. Currently, two proposed diversions into the swamp are via Hope Canal (57 m3 s-1) and Blind River (142 m3· s-1). These diversions would greatly benefit their immediate area but they are too small to influence the entire Maurepas sub-basin, especially in terms of accretion. A large diversion (> 1422 m3· s-1) is needed to deliver the adequate sediments to achieve high accretion rates and stimulate organic soil formation. © 2016 by the authors.


Hunter R.G.,Comite Resources Inc. | Day J.W.,Comite Resources Inc. | Day J.W.,Louisiana State University | Shaffer G.P.,Southeastern Louisiana University | And 8 more authors.
Water (Switzerland) | Year: 2016

The Central Wetlands Unit (CWU), covering 12,000 hectares in St. Bernard and Orleans Parishes, Louisiana, was once a healthy baldcypress-water tupelo swamp and fresh and low salinity marsh before construction of levees isolated the region from Mississippi River floodwaters. Construction of the Mississippi River Gulf Outlet (MRGO), which funneled saltwater inland from the Gulf of Mexico, resulted in a drastic ecosystem change and caused mortality of almost all trees and low salinity marsh, but closure of the MRGO has led to decreases in soil and surface water salinity. Currently, the area is open water, brackish marsh, and remnant baldcypress stands. We measured hydrology, soils, water and sediment chemistry, vegetation composition and productivity, accretion, and soil strength to determine relative health of the wetlands. Vegetation species richness is low and above- and belowground biomass is up to 50% lower than a healthy marsh. Soil strength and bulk density are low over much of the area. A baldcypress wetland remains near a stormwater pumping station that also has received treated municipal effluent for about four decades. Based on the current health of the CWU, three restoration approaches are recommended, including: (1) mineral sediment input to increase elevation and soil strength; (2) nutrient-rich fresh water to increase productivity and buffer salinity; and (3) planting of freshwater forests, along with fresh and low salinity herbaceous vegetation. © 2016 by the authors.

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