Since 1991, mississippi river water has been diverted at caernarvon, louisiana, into breton sound estuary. Modification of caernarvon diversion usace, new orleans district. Water quality analysis of a freshwater diversion at caernarvon, louisiana article pdf available in estuaries and coasts 222. Water quality analysis of a freshwater diversion at. Freshwater diversions brochure usace pdf interactive. We predicted the responses of oyster population in bse to small 142 m 3 s. River diversions are being implemented to reintroduce river water to the delta plain. The caernarvon freshwater diversion was designed to deliver up to 8,000 cubic feet per second cfs of water from the mississippi river. We determined temporal changes in land gain and loss in receiving basins and adjacent reference areas for two diversions of the mississippi river in south louisiana davis pond and caernarvon initiated in 1991 and 2002, respectively.
In an effort to restore deteriorating coastal wetlands in breton sound, louisiana, a diversion of mississippi river water into the estuarine ecosystem has been operated at caernarvon, louisiana, since 1991. Proposed 2019 operational plan twg met 11152018 no changes to ops plan proposed caernarvon freshwater diversion advisory committee. Available data for this site click to hide stationspecific text data are tidally affectedastronomical tides cause significant cycles of approximately 24. This mississippi river diversion was constructed at caernarvon in 1991 in order to divert fresh water into the plaquemines parish marshes and freshen the water of breton sound.
The diversion was implemented after a relatively long collaborative planning process beginning in the 1950s. Introduction the mississippi delta is one of the largest, and most eco. A presentation on river diversion focusing on cofferdams, diversion tunnels, diversion dams and other alternative methods. Louisiana coastal area lca, modification of caernarvon freshwater diversion feasibility study december 2009. Pdf coastal wetland restoration can be complex and expensive, and so. The net land loss after the mississippi river was diverted through three. The impacts of pulsed reintroduction of river water on a. Presented at the 16th biennial conference of the estuarine research federation, st.
Mississippi river and complaints from shrimpers due to bad shrimp years prevented more water from being diverted that may have. Request pdf challenges in collaborative governance for coastal restoration. The diversion was designed and constructed with five 15 feet gates, allowing up to 8000 cfs of river diversion to gravity flow into a conveyance. The caernarvon interagency advisory committee, an official. One such diversion is the caernarvon freshwater diversion. The caernarvon freshwater diversion was constructed in 1991 and designed to divert water from the mississippi river into a local estuary, big mar pond, previously a failed agricultural impoundment. Water from both diversions went into receiving basin with vegetated areas as did the adjoining reference areas. The caernarvon freshwater diversion is set at the 500 cfs minimum. Freshwater river diversions for marsh restoration in. The purpose of the structure is to divert mississippi river water into the breton.
For reference, a flow rate of 8,000 cfs could fill up an olympicsize swimming pool in 11 seconds or the superdome in 4. Water quality analysis of a freshwater diversion at caernarvon, louisiana. Tidal flux at the bay mouth on the order of 4000 m 3 s1, swenson et al. River, the atchafalaya river, and the caernarvon diversion. Update on plantings and tree monitoring in the vicinity of. The caernarvon freshwater diversion is set at the 500 cfs minimum caernarvon discharge caernarvon 15ppt gauge. October 2003 caernarvon diversion outfall management bs. Caernarvon freshwater diversion structure public domain. Caernarvon delta associated with the nearby caernarvon diversion is an unprecedented opportunity in the pontchartrain basin to pursue baldcypress reforestation under the more natural condition of riverine flow and delta formation from the mississippi river. The caernarvon interagency advisory committee, an official panel of stakeholders, considers scientific aspects of the. Caernarvon operational plan davis pond operational plan caernarvon operations status update.
Barataria west bank of the mississippi river diversion are proposed to be built below new orleans and were modeled by brown et al. Caernarvon diversion pulse opening february 2017 lake. Another approach is to create small breaks in the levees to allow overflow into wetlands during floods that more closely resembles natural processes. Coastal protection and restoration authority caernarvon. Mississippi river discharge through the caernarvon diversion the decline of south louisiana wetlands and wetland tree species has partly been attributed to. To make pulsed sediment diversions effective, planners must consider the concentration of sediment in the river, the location of the diversion, size and pulsing capacity, type of diversion. The caernarvon freshwater diversion structure, located at the head of breton sound estuary, became operational in 1992.
A modeling study of the impacts of mississippi river diversion and sealevel rise on water quality of a deltaic estuary. October 2003 caernarvon diversion outfall management bs03a. The caernarvon interagency advisory committee, an official panel of. Generally, the river diversion is designed aiming at the goal of its use, even partial, for the construction of permanent works. The feasibility of using caernarvon freshwater diversion. Predicting the impacts of mississippi river diversions and.
The existing caernarvon structure consists of 5 gated box culverts connecting the mississippi river with the project area. Sediment deposition at the caernarvon crevasse during the. The caernarvon freshwater diversion was designed to deliver up to 8000 cfs from. The magnitude, method and cost of river diversion works will depend upon the crosssection of the valley, the bed material in the river, the type of dam, the expected hydrological conditions during the time required for this phase of the work, and finally upon the consequences of failure of any part of the temporary works. Caernarvon freshwater diversion zselected on wrda 1965 zconstruction finished april, 1991 zlocation. The caernarvon freshwater diversion structure was completed in january 1991 by the u. The impact of the caernarvon diversion on above and belowground marsh biomass in the breton sound estuary after hurricane katrina from the pro diversion camp lake pontchartrain basin foundation.
Pdf since 1991, mississippi river water has been diverted at caernarvon, louisiana, into breton sound estuary. In the years since its construction, the caernarvon diversion has deposited significant sediment into big mar, accumulating. The purpose of the structure is to divert mississippi river water into the breton sound area estuary in southeastern louisiana, to ameriorate saltwater intrusion and associate wetland loss. Net land gain or loss for two mississippi river diversions. Water flows through davis pond worlds largest fr eshwater diversion project opened new orleans water flowed through massive metal gates for the first time today as a 2 p. Objectives and hypothesis in august 1991, a river diversion structure was opened at caernarvon, louisiana, to channel mississippi river water into the breton sound estuar y.
Caernarvon freshwater diversion dnr, usgs velocity, discharge, conductivity, salinity, gage height hydrographic and vegetation data from coastal restoration projects dnr. The vegetation in the caernarvon reference site, however, did not the show the same level of decline as indicated either by the percent vegetative cover or total marsh area, with only the northern. The louisiana coastal area lca program focuses on critical, nearterm ecosystem restoration projects and studies, as approved in the water. What is the impact of pulsing river diversion on water exchange process. Black bay nr snake island usgs site 07374526 caernarvon 5ppt gauge. Coastal protection and restoration authority caernarvon and. Breton sound estuary encompasses 1100 km2 of fresh and brackish, rapidly subsiding wetlands. The project is located on the east bank of the mississippi river near the st. Caernarvon diversion2 small river diversion 40% 50% 2. The existing caernarvon freshwater diversion project funded by the water resources development act releases water into big mar and bayou mandeville but does not force water over the marsh.
The results were confirmed for one diversion using independently collected data and supported by the example from a larger third river diversion that broke through river. Caernarvon freshwater diversion pulse opening january 4 to. An evaluation of coastal restoration projects in louisiana. Caernarvon discharge from outfall channel suspended sediment concentration in outfall channel sediment discharge through diversion mississippi river q line and tss dots experimental discharges to understand how river flow, diversion discharge, and. Soil salinity ppt in the vicinity of the caernarvon freshwater diversion. Dark black line at the site of the crevasse is the estimated width of the levee breach. It was the first project of its kind and has provided restoration specialists with useful longterm data on its effects on the receiving basin. The caernarvon freshwater diversion has been in operation since 1991 and therefore provides an opportunity to examine the longterm impacts of freshwater diversions on the receiving basin. The use of part of the river diversion works will make the structure composed with temporary and permanent structures, more economical and integrated.
River has a high influence on salinities in western portion of the basin caernarvon freshwater diversion advisory committee. Given initial conditions and these forcings, the water velocities, water depths, and salinity values were solved for each node of the triangular grid using a time step of 0. Pdf net land gain or loss for two mississippi river diversions. The diversion was designed and constructed with five 15 feet gates, allowing up to 8000 cfs of river diversion to gravity flow into a conveyance canal. Objectives and hypothesis in august 1991, a river diversion structure was opened at caernarvon, louisiana, to channel mississippi river. Breton sound estuary encompasses 1100 km 2 of fresh and brackish, rapidly subsiding wetlands. Study area total of 9,881 km2 of coastal wetlands 30% of total coastal marsh area 90% of the coastal marsh loss. Diversion dams do not generally impound water in a reservoir. Caernarvon and davis pond diversions 2020 operational plans.
The caernarvon freshwater diversion was constructed in 1991 and designed to divert water from the. A deal was negotiated between the quebec government and the grand council of the crees of quebec in october 2001 which would open the way for the rupert river to be diverted by late 2009 for a hydroelectric power project by quebec hydro the controversial james bay 2 project. Challenges in collaborative governance for coastal. Multipage pdf file usace, new orleans district army. River diversion free download as powerpoint presentation. Geomorphology and baldcypress restoration of the caernarvon.
Diversions from the main stem of the lower mississippi river are either controlled by some engineered structure for example, the caernarvon diversion or are essentially uncontrolled for example, the west bay diversion. Wetland erosion issues near the caernarvon freshwater diversion. The results were confirmed for the caernarvon diversion using a. The caernarvon freshwater diversion and the bohemia spillway are two legacy diversions located on the east bank of the mississippi river south of new orleans.
A diversion dam is a dam that diverts all or a portion of the flow of a river from its natural course. Congress under the flood control act of 1965 and the water resources development act of 1974, 1986, and 1996. Abstractin an effort to restore deteriorating coastal wetlands in breton sound, louisiana, a diversion of mississippi river water into the estuarine ecosystem has been operated at caernarvon, louisiana, since 1991. In addition to davis pond, two other structures, one completed and one proposed, are important to the future of louisianas coast. Were restoring to the mississippi river its ability to flood. Mississippi river into a local estuary, big mar pond. Lessons from the caernarvon river diversion in louisiana in an effort to restore deteriorating coastal wetlands in. The caernarvon freshwater diversion structure, 15 miles below new. The feasibility of using caernarvon freshwater diversion to prevent oil slicks from flushing into the breton sound estuary. Northwest winds push water out of the basin, which can decrease. Using ecopath with ecosim to explore nekton community. A modeling study of the impacts of mississippi river. We synthesize here the results of extensive studies on a river diversion at caernarvon, louisiana, one of the largest diversions in the delta.
Environmental atlas of the lake pontchartrain basin usgs. Wetland erosion issues near the caernarvon freshwater. The caernarvon freshwater diverthe ecosystembased modeling software ecopath with ecosim sion ced is tlie secondlargest mississippi river diversion in. In operation since 1991 discharge capacity is 227 m. Caernarvon discharge from outfall channel suspended sediment concentration in outfall channel sediment discharge through diversion mississippi river q line and tss dots experimental discharges to understand how river flow, diversion discharge, and sediment flux are connected. All measurements shown were obtained since january 2015. Project goals the primary study goal is to evaluate modifications to caernarvon diversion operations to increase wetland creation.
Bs08 project location zproject features diversion structure. Freshwater diversion from caernarvon may have been responsible for keeping the red tide out of the breton basin in 1996. But we will control that flooding in a positive sense to rebuild our state. In the years since its construction, the caernarvon diversion has. Study area diversion maximum flow capacity 227 m3 s1 for caernarvon freshwater diversion in breton sound.
Pat fitzpatrick, yee lau, jim chen, kelin hu, valentine anantharaj, and suzanne shean. Wetland loss associated with hurricane storm surge near. Pdf water quality analysis of a freshwater diversion at. Simulating fish movement responses to and potential. Based on the usgs hydrologic station in the caernarvon diversion canal, during the period of the opening, discharge from the cfd ranged from approximately 1,000 cfs cubic feet per second to. Mississippi river commission vicksburg, mississippi august 19, 2010 operation of the davis pond and caernarvon freshwater diversion structures in the aftermath of the deepwater horizon oil spill the mississippi river commission notes a strong concern with regard to the state of louisianas operation of the. Large river diversions into organic soils, an unproven restoration approach, may be causing wetland loss, not restoring them. Reconnecting the mississippi river to the wetlands in this way mimics natural processes and restores the river s capacity to build land.
Usgs 295124089542100 caernarvon outfall channel at. Why study the caernarvon freshwater diversion and delta. The structure is located on the east bank of the mississippi river mile 82 in plaquemines parish near braithwaite. The project focuses on the existing caernarvon diversion located at river mile 81. Mar 25, 2014 the impact of the caernarvon diversion on above and belowground marsh biomass in the breton sound estuary after hurricane katrina from the pro diversion camp lake pontchartrain basin foundation. Study area diversion maximum flow capacity 227 m3 s1 for caernarvon. What can the caernarvon diversion and bohemia spillway teach. The caernarvon freshwater diversion project was authorized by the u. Comparison of caernarvon and mississippi river discharge. Breton diversion east bank of the mississippi river and mid. The louisiana coastal restoration plan proposes to build a small number of large river diversions. The caernarvon diversion is located at river mile 81. Data are tidally affectedastronomical tides cause significant cycles of approximately 24. Water from both diversions went into receiving basins with vegetated areas as did the adjoining reference areas.