Dissolved  Oxygen
  Dissolved  Oxygen serves  as an
  indicator of the biological health of
  a water body.  Concentrations vary
  naturally with water temperature
  and  altitude.  DO   levels   can
  fluctuate throughout the day  and
  are affected by changes in  water
  temperature and the concentration
  of organic materials.  Industrial or
  municipal wastes can increase the
  concentration  of  organic matter.
  Lack  of  shade  availability  and
  increased  thermal  discharges  can
  raise   water  temperature   and,
  therefore, impact dissolved oxygen
  levels.
                                             Tule River at Tule River Indian Reservation
  Understanding the Effects of Dissolved Oxygen on a Water Body:  Dissolved oxygen
  levels vary for a number of reasons. If more oxygen is consumed than is produced, and oxygen
  levels drop below their natural levels, some sensitive animals may weaken, move away, or die.
  Because of this naturally occurring fluctuation, interpreting data may be difficult.  It would be
  most important to keep  track of metadata when monitoring dissolved oxygen.   Because
  dissolved oxygen readings can be variable (daily and seasonally), it is important to have enough
  data to adequately determine trends and/or compliance with tribal, state, or federal standards.
                                          Monitoring Equipment:  Depending upon
                                          monitoring  objectives  set  forth  in   an
                                          environmental   program,    the   following
                                          equipment options  are commonly used to
                                          collect DO data from the field.

                                          Readily available and economically priced:
                                             • Dissolved Oxygen Kits

                                          Greater precision and higher cost:
                                             • Meters
                                             • Multi parameter Probes
                                             • Contract Laboratories (if necessary)

                                          For additional information:
                                          www.epa.gov/owow/monitoring/volunteer/stream
 Using a multi parameter probe to measure DO at Yavapai-Prescott
For more information, please contact your CWA Project Officer or Kristin Gullatt, Manager of the Water Division, Tribal Office at (415) 972-3432.

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