Thirteen year (1993-2005) dissolved oxygen trend in the Hackensack River

Dissolved Oxygen in the Hackensack River: 2005 Update

The Meadowlands Environmental Research Institute has completed its monitoring of the surface water of the Hackensack River for 2005. All five sites were sampled once during each season. An additional data point representing the 2005 yearly average is depicted in the chart above.

The average concentration for 2005 was 5% below the prior year's average. The long term trend for dissolved oxygen continues to be positive. The value of 7.2 for 2005 was above the running average, which continues to be well above criteria and stress levels. As in 1993 and 1998, an extremely dry summer was encountered, diminishing DO levels. As in prior years, oxygen rebounded with the resumption of normal precipitation in the fall.

1 NJDEP criteria SE-2 (NJAC 7:9B) allows for secondary contact recreation and maintenance, migration and propagation of biota.
2 Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen, USEPA, November 2000.