Estimating the potential for submergence for two wetlands in the Mississippi River Delta

Rybczyk, John; Cahoon, Donald R.

doi:10.1007/bf02691346

Cited by 87 publications

(32 citation statements)

References 18 publications

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“…These short-term measurements of process rates (for example, sediment accretion, root expansion, belowground primary production and decomposition, autocompaction and soil shrink-swell) can be used to calibrate, parameterize and validate locally relevant models 36 to make longer-term predictions of coastal wetland response to changes in the rate of SLR. Thus, although RSET data provide direct, shortterm indications of marsh resilience, modelling allows prediction at the appropriate timescales for management action 35,42,43,58 . Second, to calculate the local difference between wetland elevation change and sea-level change so that absolute site vulnerability can be compared across sites over a broad geographic area (for example, a continent), RSETs need to be levelled (referenced) into a common regional vertical datum 59 .…”

Section: Surmountable Limitations To Rset Datamentioning

confidence: 99%

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

et al. 2013

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Section: Surmountable Limitations To Rset Datamentioning

confidence: 99%

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

et al. 2013

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“…However, Rybczyk et al [50] and Brantley et al [51] found that waters diverted from municipal wastewater treatment facilities stimulated vertical accretion in coastal swamps of Louisiana. Hunter et al [52] found that the Mandeville assimilation wetland, also located in coastal Louisiana, had average TN and TP loading rates of 56.5 and 13.9 g¨m´2¨year´1 from 2006-2013, respectively, which resulted in average swamp aboveground net primary production of an impressive 1250 g¨m´2¨year´1.…”

Section: Discussionmentioning

confidence: 99%

Decline of the Maurepas Swamp, Pontchartrain Basin, Louisiana, and Approaches to Restoration

Shaffer

Day

Kandalepas

et al. 2016

Water

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Abstract: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 m 3¨s´1 ) and Blind River (142 m 3¨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 m 3¨s´1 ) is needed to deliver the adequate sediments to achieve high accretion rates and stimulate organic soil formation.

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“…Rybczyk et al (1998) extended the Callaway et al (1996) approach to simulate elevation changes as affected by sea level rise in a forested wetland in the southeastern United States. Rybczyk and Cahoon (2002) and Day et al (1999) used a similar approach to simulate effects of sea level rise on marsh accretion in Louisiana and the Venice Lagoon. Most recently, Swanson et al (2013) used a modified version of the Callaway et al (1996) model to evaluate changes in marsh surface elevation and the impact of these elevation changes on marsh habitat for specific species of concern.…”

Section: Introductionmentioning

confidence: 99%

Impounded Marshes on Subsided Islands: Simulated Vertical Accretion, Processes, and Effects, Sacramento-San Joaquin Delta, CA USA

Deverel¹,

Ingrum²,

Lucero³

et al. 2014

SFEWS

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There is substantial interest in stopping and reversing the effects of subsidence in the Sacramento-San Joaquin Delta (Delta) where organic soils predominate. Also, the passage of California Assembly Bill 32 in 2006 created the potential to trade credits for carbon sequestered in wetlands on subsided Delta islands. The primary purpose of the work described here was to estimate future vertical accretion and understand processes that affect vertical accretion and carbon sequestration in impounded marshes on subsided Delta islands. Using a cohort-accounting model, we simulated vertical accretion from 4,700 calibrated years before present (BP) at a wetland area located within Franks Tract State Recreation Area (lat 38.059, long −121.611, hereafter, "Franks Wetland")-a small, relatively undisturbed marsh island-and at the Twitchell Island subsidencereversal demonstration project since 1997. We used physical and chemical data collected during the study as well as literature values for model inputs. Model results compared favorably with measured rates of vertical accretion, mass of carbon sequestered, bulk density and organic matter content.From 4,700 to model-estimated 350 years BP, the simulated rate of vertical accretion at Franks Wetland averaged about 0.12 cm yr -1 , which is within the range of rates in tidal wetlands worldwide. Our model results indicate that large sediment inputs during the last 150 to 200 years resulted in a higher accretion rate of 0.3 cm yr -1 . On Twitchell Island, greater organic inputs resulted in average vertical accretion rates as high as 9.2 cm yr -1 . Future simulations indicate that the managed impounded marsh will accrete highly organic material at rates of about 3 cm yr -1 . Model results coupled with GIS analysis indicate that large areas of the periphery of the Delta, if impounded and converted to freshwater marsh, could be restored to tidal elevations within 50 to 100 years. Most of the central Delta would require 50 to 250 years to be restored to projected mean sea level. A large portion of the western Delta could be restored to mean sea level within 50 to 150 years (large areas on Sherman, Jersey, and Bethel islands, and small areas on Bradford, Twitchell, and Brannan islands, and Webb Tract). We estimated that long-term carbon sequestration rates for impounded marshes such as the Twitchell Island demonstration ponds will range from 12 to 15 metric tons carbon ha -1 yr -1 . Creation of impounded marshes on Delta islands can substantially benefit levee stability as demonstrated by cumulative force and hydraulic gradient calculations.1 HydroFocus, Inc., Davis, CA USA 2 U.S. Geological Survey, California Water Science Center Sacramento, CA USA * Corresponding author: sdeverel@hydrofocus.com SAN FRANCISCO ESTUARY & WATERSHED SCIENCE 2 INTRODUCTIONThe 300,000-ha Sacramento-San Joaquin Delta is a critical natural resource, important agricultural region and the hub for California's water supply. Within an area of about 81,000 ha in the central Delta, an estimated 4.5 billion ...

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Estimating the potential for submergence for two wetlands in the Mississippi River Delta

Cited by 87 publications

References 18 publications

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

Decline of the Maurepas Swamp, Pontchartrain Basin, Louisiana, and Approaches to Restoration

Impounded Marshes on Subsided Islands: Simulated Vertical Accretion, Processes, and Effects, Sacramento-San Joaquin Delta, CA USA

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