appendix b final 2008 biological surveys of los angeles and long ...

2.0 Water Quality
2.0 WATER QUALITY
2.1 INTRODUCTION
This section presents the results and key findings of water quality measurements conducted
within the Ports of Los Angeles and Long Beach during July 2008. Methods used for water
quality measurements are described in Section 2.2. Results of water quality measurements are
provided in Section 2.3. Discussions of spatial patterns and comparisons with historical
conditions are provided in Sections 2.4 and 2.5, respectively.
The water quality parameters measured consisted of temperature, salinity, dissolved oxygen
(DO), acidity/alkalinity (pH), and light transmittance/water clarity (transmissivity). Temperature
and salinity are standard hydrographic measures used to characterize different water masses.
These can be important in a port/harbor setting that receives freshwater flows from storm drains
and other watershed input sources. DO, pH, and transmissivity are key water quality indicators
for the protection of beneficial uses, as defined in the Basin Plan and California Ocean Plan.
For example, human activities can result in reductions in DO concentrations and water clarity
and/or alter pH, which causes adverse effects on biological resources. However, it is important
to note that these water quality parameters also reflect natural physical, chemical, and biological
processes that can result in changes at tidal, daily (diurnal), seasonal, and longer (decadal) time
periods. Thus, water quality data typically are evaluated in the context of deviations from
natural or background conditions.
2.2 METHODOLOGY
Water quality sampling was
conducted during the July (summer)
2008 survey. Water quality
characteristics were measured as
continuous vertical profiles at each
of 29 stations, 15 stations in the Port
of Los Angeles and 14 in the Port of
Long Beach (Figure 2.2-1).
Sampling for Station LA14 was
conducted at two locations
(designated i and o), for inner and
outer Consolidated Slip, to match
historical sampling locations. Station
coordinates and water depths are
listed in Table 2.2-1. Water depths
for the stations ranged from 4 to 25 meters [m] (13 to 82 feet [ft]).
Sampling was conducted during a one-day survey on July 30, 2008. The survey was conducted
from a rigid hulled inflatable vessel. A Lowrance Model S-337C DF (Dual Frequency)
differential GPS was used for navigation and vessel positioning. All stations were sampled
while live-boating (i.e., vessel was not anchored during the casts).
Each of the water quality parameters was measured as continuous vertical profiles using a
Seabird model SBE19 Conductivity Temperature Depth (CTD) instrument with additional pH
and DO probes and a SeaTech CST-714PR, 0.25-centimeter (cm) pathlength transmissometer.
All instruments were factory calibrated at SeaBird Electronics, Inc., in Bellevue, WA, prior to the
survey.
2008 Biological Surveys of Los Angeles and Long Beach Harbors 2–1
April 2010