The legacy of wetland drainage on the remaining peat in the Sacramento-San Joaquin Delta, California, USA

By: , and 



Throughout the world, many extensive wetlands, such as the Sacramento-San Joaquin Delta of California (hereafter, the Delta), have been drained for agriculture, resulting in land-surface subsidence of peat soils. The purpose of this project was to study the in situ effects of wetland drainage on the remaining peat in the Delta. Peat cores were retrieved from four drained, farmed islands and four relatively undisturbed, marsh islands. Core samples were analyzed for bulk density and percent organic carbon. Macrofossils in the peat were dated using radiocarbon age determination. The peat from the farmed islands is highly distinct from marsh island peat. Bulk density of peat from the farmed islands is generally greater than that of the marsh islands at a given organic carbon content. On the farmed islands, increased bulk density, which is an indication of compaction, decreases with depth within the unoxidized peat zone, whereas, on the marsh islands, bulk density is generally constant with depth except near the surface. Approximately 55–80% of the original peat layer on the farmed islands has been lost due to landsurface subsidence. For the center regions of the farmed islands, this translates into an estimated loss of between 2900-5700 metric tons of organic carbon/hectare. Most of the intact peat just below the currently farmed soil layer is over 4000 years old. Peat loss will continue as long as the artificial water table on the farmed islands is held below the land surface.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The legacy of wetland drainage on the remaining peat in the Sacramento-San Joaquin Delta, California, USA
Series title Wetlands
DOI 10.1672/08-97.1
Volume 29
Issue 1
Year Published 2009
Language English
Publisher Society of Wetland Scientists
Publisher location McClean, VA
Contributing office(s) California Water Science Center
Description 15 p.
First page 372
Last page 386
Country United States
State California
Other Geospatial Sacramento-San Joaquin Delta
Online Only (Y/N) N
Additional Online Files (Y/N) N
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