2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
were out of the range of the capability of the unit. Accepted data were plotted graphically, numerically
analyzed, and reviewed to generate summary statistics.
Water quality monitoring during 2008 was severely impacted by repeated instrument failures. The
instruments were repeatedly repaired and in some cases replaced, but new malfunctions arose during
each monitoring interval. Despite intensive coordination and follow-up with the manufacturer, it
appears that the quality of this previously reliable instrument manufacturer is no longer suitable for the
present monitoring needs and an alternate instrument manufacturer will be used for future monitoring
work.
Results
In January 2008 the instrument at Station 1 only functioned correctly for the first four days of the 30-
day deployment (January 10-14). The instrument at Station 2 collected data for 30 days (January 10-
February 10), with all data acceptable except the second half of the salinity data. The data are
presented in Figure 1-13. During the four-day period beginning January 10, 2008, temperature ranged
from 12.8 to 14.3°C at Station 1, with a mean of 13.4°C. During the 30-day period beginning January
10, 2008 at Station 2, temperature ranged from 11.3 to 15.1°C, with a mean of 13.4°C. Salinity was
similar at both stations, with a mean of 32.2 ppt at Station 1 (January 10-14) and 32.5 ppt (January 10-
22) at Station 2. The turbidity data showed considerably more noise than would be expected, and it is
believed that animals or drift algae regularly passing near the optical sensor likely caused the erratic
data. The retrieved units were noted to have eggs of the opistobranch Navanax inermis around the
sensors, which may have interfered with the turbidity readings. In general, turbidity ranged between 0
and 10 at both stations. Quality control readings taken with a separate instrument at time of
deployment, retrieval, and mid-way through the logging period measured a turbidity between 5 and 8
NTU at Station 1 and between 7 and 15 NTU at Station 2. Dissolved oxygen at Station 1 ranged from
6.8 to 8.9 mg/L, with a mean of 7.9 mg/L during the 4-day logging period. Dissolved oxygen at
Station 2 ranged from 6.5 to 9.5 mg/L, with a mean of 8.0 mg/L.
In April 2008 the instrument at Station 1 failed completely for the entire logging period. The
instrument at Station 2 was on loan from Hydrolab Corporation due to the ongoing maintenance on
other M&A instruments. This instrument only collected data for the first 18 of the 30 days of
deployment (April 2-20) and only the temperature and DO probes worked properly. The retrieved data
are presented in Figure 1-14. During the 18-day period beginning April 2, 2008, temperature ranged
from 12.7 to 20.1°C at Station 2, with a mean of 16.1°C. Dissolved oxygen at Station 2 ranged from
5.5 to 9.6 mg/L, with a mean of 7.1 mg/L.
In July 2008 the instrument at Station 1 collected data for the full 30-day monitoring period (July 1-
30), but only the temperature and first half of the salinity data were acceptable. The instrument at
Station 2 collected data for the full 30-day monitoring period, with most of the data acceptable. The
data are presented in Figure 1-15. At Station 1, temperature ranged from 19.2 to 26.2°C, with a mean
of 24.0°C. At Station 2, temperature was lower and ranged from 17.2 to 23.7°C, with a mean of
20.8°C. Salinity was higher at Station 1, ranging from 32.3 to 36.1, with a mean of 34.5 ppt (July 1-
18), than at Station 2, where salinity ranged from 30.8 to 34.9, with a mean of 33.7 ppt (July 1-30).
Turbidity data from Station 1 were unacceptable, but quality control readings taken with a separate
instrument at time of deployment, retrieval, and mid-way through the logging period measured a
turbidity between 13 and 24 NTU at Station 1. Turbidity data collected at Station 2 were acceptable
Merkel & Associates, Inc. 67