Subsidence of Peat in California and Florida

Prokopovich, Nikola P.

doi:10.2113/gseegeosci.xxii.4.395

Cited by 28 publications

(30 citation statements)

References 2 publications

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“…In his review of the history, causes, and costs of the flooding of Delta islands from the early 1900s to the 1980s, Prokopovitch (1985) concluded that levee foundation instability resulting at least partially from subsidence became an important factor in island flooding after the 1940s. Duncan and Houston (1983), CDWR (1982), and the U.S. Army Corps of Engineers (1982) generally agreed.…”

Section: Farming and Drainagementioning

confidence: 99%

“…Duncan and Houston (1983), CDWR (1982), and the U.S. Army Corps of Engineers (1982) generally agreed. For example, foundation failure caused 12 of 18 failures that occurred from 1950 to the early 1980s (Prokopovitch 1985). Subsidence lowered island interiors and created height differences between island surfaces and adjacent surface-water levels (Figure 3), which contributed levee internal failures.…”

Section: Farming and Drainagementioning

confidence: 99%

“…Prokopovitch (1985) stated that before dam construction, greater numbers of levees failed from overtopping, relative to after the 1940s. The decrease in levee failure from overtopping may have been lessened because of reduced Delta inflow.…”

Section: Flood Controlmentioning

confidence: 99%

“…Hopf (2011) and Prokopovitch (1985) noted an increased rate of levee failures after the 1906 earthquake. We can only speculate on whether earthquake-induced embankment cracking, perhaps combined with accelerated settlements, may have contributed to these failures.…”

Section: Seismic Threats To Leveesmentioning

confidence: 99%

“…For example, The San Francisco Call on July 6, 1906 described "alarming high conditions on the San Joaquin River due to warm weather." 13 Prokopovitch (1985) Figure 7), and cracks.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Factors and Processes Affecting Levee System Vulnerability

Deverel¹,

Bachand²,

Brandenberg³

et al. 2016

SFEWS

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We appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils caused subsidence, which contributed to levee internal failures. Subsidence rates decreased with time, but still contributed to levee instability. Modeling changes in seepage and static slope instability suggests an increased probability of failure with decreasing peat thickness. Additional data is needed to assess the spatial and temporal effects of subsidence from peat thinning and deformation. Large-scale, state investment in levee upgrades (> $700 million since the mid-1970s) has increased conformance with applicable standards; however, accounts conflict about corresponding reductions in the number of failures.Modeling and history suggest that projected increases in high-flow frequency associated with climate change will increase the rate of levee failures. Quantifying this increased threat requires further research. A reappraisal of seismic threats resulted in updated ground motion estimates for multiple faults and earthquake-occurrence frequencies. Estimated ground motions are large enough to induce failure. The immediate seismic threat, liquefaction, is the sudden loss of strength from an increase in the pressure of the pore fluid and the corresponding loss of inter-particle contact forces. However, levees damaged during an earthquake that do not immediately fail may eventually breach. Key sources of uncertainty include occurrence frequencies and magnitudes, localized ground motions, and data for liquefaction potential.Estimates of the consequences of future levee failure range up to multiple billions of dollars. Analysis of future risks will benefit from improved description of levee upgrades and strength as well as consideration of subsidence, the effects of climate change, and earthquake threats. Levee habitat ecosystem benefits in this highly altered system are few. Better recognition and coordination is needed among the creation of high-value habitat, levee needs, and costs and benefits of levee improvements and breaches.

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Section: Farming and Drainagementioning

confidence: 99%

Section: Farming and Drainagementioning

confidence: 99%

Section: Flood Controlmentioning

confidence: 99%

Section: Seismic Threats To Leveesmentioning

confidence: 99%

“…For example, The San Francisco Call on July 6, 1906 described "alarming high conditions on the San Joaquin River due to warm weather." 13 Prokopovitch (1985) Figure 7), and cracks.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Factors and Processes Affecting Levee System Vulnerability

Deverel¹,

Bachand²,

Brandenberg³

et al. 2016

SFEWS

View full text Add to dashboard Cite

show abstract

Estimation and Uncertainty of Recent Carbon Accumulation and Vertical Accretion in Drained and Undrained Forested Peatlands of the Southeastern USA

et al. 2017

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The purpose of this study was to determine how drainage impacts carbon densities and recent rates (past 50 years) of vertical accretion and carbon accumulation in southeastern forested peatlands. We compared these parameters in drained maple‐gum (MAPL), Atlantic white cedar (CDR), and pocosin (POC) communities in the Great Dismal Swamp National Wildlife Refuge (GDS) of Virginia/North Carolina and in an intact (undrained) CDR swamp in the Alligator River National Wildlife Refuge (AR) of North Carolina. Peat cores were analyzed for bulk density, percent organic carbon, and 137Cs and 210Pb. An uncertainty analysis of both 137Cs and 210Pb approaches was used to constrain error at least partially related to mobility of both radioisotopes. GDS peats had lower porosities (89.6% (SD = 1.71) versus 95.3% (0.18)) and higher carbon densities (0.082 (0.021) versus 0.037 (0.009) g C cm−3) than AR. Vertical accretion rates (0.10–0.56 cm yr−1) were used to estimate a time period of ~84–362 years for reestablishment of peat lost during the 2011 Lateral West fire at the GDS. Carbon accumulation rates ranged from 51 to 389 g C m−2 yr−1 for all sites. In the drained (GDS) versus intact (AR) CDR sites, carbon accumulation rates were similar with 137Cs (87GDS versus 92AR g C m−2 yr−1) and somewhat less at the GDS than AR as determined with 210Pb (111GDS versus 159AR g C m−2 yr−1). Heightened productivity and high polyphenol content of peat may be responsible for similar rates of carbon accumulation in both drained and intact CDR peatlands.

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Present-day oxidative subsidence of organic soils and mitigation in the Sacramento-San Joaquin Delta, California, USA

Deverel¹,

Ingrum²,

Leighton³

2016

Hydrogeol J

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Subsidence of organic soils in the Sacramento-San Joaquin Delta threatens sustainability of the California (USA) water supply system and agriculture. Land-surface elevation data were collected to assess present-day subsidence rates and evaluate rice as a land use for subsidence mitigation. To depict Delta-wide present-day rates of subsidence, the previously developed SUBCALC model was refined and calibrated using recent data for CO2 emissions and land-surface elevation changes measured at extensometers. Land-surface elevation change data were evaluated relative to indirect estimates of subsidence and accretion using carbon and nitrogen flux data for rice cultivation. Extensometer and leveling data demonstrate seasonal variations in land-surface elevations associated with groundwater-level fluctuations and inelastic subsidence rates of 0.5–0.8 cm yr–1. Calibration of the SUBCALC model indicated accuracy of ±0.10 cm yr–1 where depth to groundwater, soil organic matter content and temperature are known. Regional estimates of subsidence range from <0.3 to >1.8 cm yr–1. The primary uncertainty is the distribution of soil organic matter content which results in spatial averaging in the mapping of subsidence rates. Analysis of leveling and extensometer data in rice fields resulted in an estimated accretion rate of 0.02–0.8 cm yr–1. These values generally agreed with indirect estimates based on carbon fluxes and nitrogen mineralization, thus preliminarily demonstrating that rice will stop or greatly reduce subsidence. Areas below elevations of –2 m are candidate areas for implementation of mitigation measures such as rice because there is active subsidence occurring at rates greater than 0.4 cm yr–1.

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Subsidence of Peat in California and Florida

Cited by 28 publications

References 2 publications

Factors and Processes Affecting Levee System Vulnerability

Factors and Processes Affecting Levee System Vulnerability

Estimation and Uncertainty of Recent Carbon Accumulation and Vertical Accretion in Drained and Undrained Forested Peatlands of the Southeastern USA

Present-day oxidative subsidence of organic soils and mitigation in the Sacramento-San Joaquin Delta, California, USA

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