4.2 Oregon Estuarine Classification Study 
As part of an effort to classify estuaries by the susceptibility of their submerged aquatic vegetation 
and food webs to nutrients, WED surveyed seven Oregon estuaries during the dry seasons of 2004 and 
2005 (Lee et ah, 2006). The estuaries sampled have regional drivers and landuse characteristics 
similar to the Yaquina Estuary. Their watersheds were primarily forested (66-86%) with low land 
development (high and low intensity development < 1%), and low human population densities (4 - 25 
individuals km" 2 ; Lee et al, 2006). The estuaries sampled (Alsea, Nestucca, Yaquina, Salmon River, 
Coos, Umpqua River and Tillamook) vary in size from 2 to 55 km , and from river dominated to ocean 
dominated. As is typical of many PNW estuaries, they have extensive intertidal zones with the 
percentage of intertidal area ranging from 32 to 87% of total estuarine area. 
Water quality data together with measurements of the natural abundance stable isotope ratio for 
nitrogen (5 I5 N) of green macroalgae data were collected to evaluate current water quality conditions. 
These data were also used to divide each estuary into oceanic and riverine dominated zones (in terms 
of nitrogen sources). The sampling consisted of high tide and low tide cruises and of short-term 
deployments of water quality datasondes. During each cruise between 10 and 17 stations were 
sampled in each estuary, depending upon the size of the estuary, and the stations extended from the 
mouth of the estuary to the fresh water portions of the estuary for all systems except Coos Estuary 
(lowest salinity in Coos was 14 psu). For more details on the methods used and the data collected, see 
Lee et al. (2006). 
4.3 National Coastal Assessment (NCA) 
As a part of the NCA, the Environmental Monitoring and Assessment Program (EMAP) 
assessed the condition of estuarine resources of Oregon based on a range of indicators of 
environmental quality, including water quality indicators (chlorophyll a , nutrients, and dissolved 
oxygen). The study utilized a stratified random sampling design and sampled over two years (1999- 
2000). The NCA Oregon estuary data set was obtained during the summer, and thus corresponds to 
the Yaquina Estuary “dry season.” The NCA data set allows comparison of Yaquina Estuary values 
for water quality parameters (e.g. median DO) to values for the same parameter across the set of all 
Oregon estuaries. 
Details of the sampling program and results of the Oregon NCA assessment are provided in 
Nelson et al. (2004). Briefly, the Oregon 1999 sampling design consisted of 50 sites distributed among 
30 
