Half hour data files are available at: http://www.ess.uci.edu/~marsh/. This is one of two paired flux towers that were located in separate ponds that were subject to different water treatments (US-SJ1 and US-SJ2). Tower 2 is located in the southeastern corner, placing it on the farthest side from the predictable easterly oceanic breeze. The San Joaquin Marsh is one of the final remnants of a wetland, prior to the early 1900's, covered 2100 ha along San Diego Creek. Most of the regional wetlands were drained for agriculture in the early 20th century. Despite regional wetland removal, the San Joaquin remained intact. During the 1950's, vegetation was cleared to promote duck hunting. No further disturbances have occurred since the clearing. The hydroperiod is partly managed by the SJFM VC Reserve and the Irvine Ranch Water District. During the spring months, water volume begins to reduce by evapotranspiration and subsurface draining. The remaining standing water disappears during the summer. The wetland is annually replenished in January and December to a depth of 1 m in an effort to mimic natural hydrocycles.

1) Spatial and temporal patterns of wetland evapotranspiration, primary production, and nutrient cycling; 2) Rate and seasonal variation of canopy, subcanopy, and total evapotranspiration; 3) Controls and limits of total evapotranspiration