Chapter 8: Water Quality in the Coos Estuary and Lower Coos Watershed
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Chapter 8: Water Quality in the Coos Estuary and Lower Coos Watershed Jenni Schmitt, Erik Larsen, Ali Helms, Colleen Burch Johnson, Beth Tanner, Ana Andazola-Ramsey - South Slough NERR Physical Factors: Multiple waterways in the project area are considered water quality-limited under the Clean Water Act for high temperatures and low dissolved oxygen. Nutrients: Phosphorous levels are higher near the mouth and nitrogen levels are higher after precipitation events; however, nutrient levels appear to be generally healthy. Bacteria: Approximately 20% of monitored sites have maximum bacteria levels exceeding state bacteria criteria for fish and shellfish. Subsystems: CR- Coos River, CS- Catching Slough, HI- Haynes Inlet, IS- Isthmus Slough, LB- Lower Bay, NS- North Other Pollutants: Previously operational point Slough, PS- Pony Slough, SS- South Slough, UB- Upper Bay sources of pollution (e.g., former marina on Isthmus Slough) may still pose a threat to water quality. Remaining estuarine waters remain essentially unstudied. Water Quality in the Coos Estuary and the Lower Coos Watershed 8-1 Chapter 8: Water Quality The Confederated Tribes of Coos, Lower in the Coos Estuary Umpqua and Siuslaw Indians (CTCLUSI) began and Lower Coos Watershed almost identical continuous water quality monitoring in the lower Coos estuary in 2006. Their data are collected in annual reports This chapter includes four data sum- which have been summarized in the Physical maries: Physical Factors, Nutrients, Factors section (CTCLUSI 2007, 2008, 2009, Bacteria, and Other Pollutants – 2010, 2011, 2012, 2013). each describing the most current In addition, the National Oceanic and Atmo- research on the status and trends spheric Administration (NOAA) operates a (where the data allow) of water meteorological and oceanographic station at quality in the Coos Estuary. the mouth of South Slough, which has been collecting water temperature data since 1993 (NOAA 2014). Hourly raw data were down- Physical Factors: The most comprehensive loaded from NOAA and analyzed. information for physical water quality param- eters (dissolved oxygen, water temperature, Short-term continuous data can also inform pH, salinity, turbidity, depth) comes from our understanding of water quality. Data used long-term continuous water quality monitor- in this report include the following: ing efforts (i.e., data recorded by automated data collectors every 15 to 30 minutes). South • A regional eelgrass study that collected Slough National Estuarine Research Reserve water temperature data every hour from (SSNERR) staff began continuous monitoring summer 1998 to fall 2001 at four sites in efforts in 1995 and now have five water quali- the Coos estuary (Thom et al. 2003); and ty data collection stations in the South Slough estuary (SWMP 2014). • Stream water quality data from summer 2011 monitoring at 15 sites in the South Data from these stations have been analyzed Slough watershed described in Cornu et previously (O’Higgins and Rumrill 2007; Cornu al. (2012). et al. 2012) and are reported here with the benefit of additional analyses of the most The description of the status of stream water recent data. quality was additionally informed by several short-term data collection efforts in the Coos In the fall 2013, SSNERR staff installed four River subsystem by ODEQ (ODEQ 2006b, additional continuous monitoring stations in 2006d, 2007a, 2009b). the Coos estuary. Data from these new sta- tions are also summarized for this inventory (SSNERR 2014). 8-2 Water Quality in the Coos Estuary and the Lower Coos Watershed Several datasets from long-term monitoring Nutrients: The nutrient summary is partially “grab” efforts (i.e., single, manually collected based on an ODEQ report that assessed water samples) were analyzed, including: quality in the Coos estuary and other Oregon estuaries (Sigmon et al. 2006). In addition, • Monthly sampling of salinity and tem- raw data collected during later years of the perature data taken by Oregon Depart- same project were analyzed in this section ment of Agriculture (ODA) as part of their (ODEQ 1999, 2001a, 2004, 2005a, 2006a). ongoing fecal coliform sampling program (ODA 2011); and Several raw datasets were analyzed and sum- marized for this inventory including monthly • Daily data collection from 1966-1997 near quality-checked nutrient sampling in the the mouth of the Coos estuary collected South Slough (SWMP 2012) and data from for the Shore Station Program, a collab- several ODEQ projects (ODEQ 2006d, 2007c, oration between the University of San 2009c). Diego and various institutions across the Pacific Northwest, including the Oregon Annual reports from CTCLUSI provided Institute of Marine Biology (OIMB) in information on two sites in the lower Coos Charleston, Oregon (Shore Stations Pro- estuary, and information on a single site in gram 1997). the upper estuary (CTCLUSI 2007, 2008, 2009, 2010, 2011, 2012, 2013). The remaining data discussed in this report come from studies which used data collected Stream nutrients information was provided during very short-term data collector de- by a “State of the Watersheds” assessment ployments or grab sampling, including the of the South Slough watershed (Cornu et al. following: CoosWA 2002, 2006, 2008; Hayslip 2012). et al. 2006; Lee II and Brown 2009; Shanks et al. 2011; Sigmon et al. 2006; and Weybright Bacteria: The bacteria summary is based on 2011, along with the following unpublished several data sources including several ODEQ sources: 1) Quality-checked data collected studies (ODEQ 2005a, 2007b). by ODEQ for various projects downloaded ODA’s monthly fecal coliform data from shell- from their Laboratory Analytical Storage and fish growing areas were analyzed and summa- Retrieval (LASAR) database and reviewed for rized for this inventory (ODA 2014). this summary (ODEQ 2005b, 2005c, 2006a, 2006b, 2006c, 2007a, 2007c, 2009c); 2) Similarly, data from SSNERR’s System-Wide Oregon Department of Fish and Wildlife’s Monitoring Program (SWMP) provided (ODFW’s) annual fish monitoring seine pro- monthly E. coli and total coliforms bacteria gram (ODFW 2013); and 3) A joint study from information (SSNERR 2013). Marshfield High School and Oregon State University (Coastnet 1999). Water Quality in the Coos Estuary and the Lower Coos Watershed 8-3 Other reports on estuarine bacteria included POPs at Merritt Lake, all of which are interna- here are: Souder 2003 and annual reports by tionally recognized for their high potential for CTCLUSI (CTCLUSI 2007, 2008, 2009, 2010, environmental damage (Water Board 2012; 2011, 2012, 2013). Stockholm Convention 2008). Stream bacteria data in South Slough were Data Gaps and Limitations also derived from Cornu et al. 2012. Physical Factors: Continuous water quality Other Pollutants: Only relatively sparse data monitoring (automated data collection on a sets describing dissolved metal concentra- regular interval [e.g., 15 minutes]) provides tions are available for the Pony Slough, Coos the best characterization of physical water River, and Isthmus Slough subsystems (ODEQ quality parameters. These continuously 1995, 1998, 2002, 2006a, 2006c, 2006d, recorded data are most complete in the 2007c, 2007d, 2009a, 2009b; Water Board South Slough estuary and the lower bay. New 2012). stations recently installed in the upper bay by the Coquille Indian Tribe and SSNERR at More robust dissolved metal concentration McCullough Bridge, Isthmus Slough, Catching data are available for South Slough from Slough and Coos River will provide a more ODEQ’s groundwater well monitoring pro- complete picture of those parts of the Coos gram at the former site of Coos County’s Joe estuary in years to come. Ney Landfill. The most recent data come from 2012. Water temperature data from NOAA’s Tides and Currents site in Charleston are raw data ODEQ has monitored total organic carbon and have not been subjected to quality con- (TOC) in the South Slough, Isthmus Slough, trol or quality assurance procedures. NOAA and Coos River subsystems (ODEQ 2001b, states that these data “do not meet the cri- 2007d, 2009a, 2009b) on a “sporadic” basis; teria and standards of official National Ocean the most recent data were collected in 2009. Service data. They are released for limited Additionally, the Coos Bay/North Bend Water public use as preliminary data to be used only board monitored TOC from 2010-2012 in with appropriate caution”. Pony Slough (Pony Creek and Merritt Lake) and Lower Bay (North Spit) subsystems as Data from the Shore Stations Program were part of their drinking water program (Water checked for key entry errors only and not Board 2012). analyzed for overall quality. We analyzed and reported on these data as-is. Data for assessing dissolved herbicides, pesticides, and other persistent organic Aside from the long-term monitoring efforts pollutants (POPs) are sparse. The Coos Bay/ described above, most of the physical factors North Bend Water board monitors for eight data used in this inventory come from short- 8-4 Water Quality in the Coos Estuary and the Lower Coos Watershed term studies. Short term studies provide Stream nutrient data included three sites in only a snapshot of water quality. Because South Slough’s upper watershed. All other most physical factors (e.g., turbidity) fluctu- subsystems are lacking in any stream (fresh- ate widely relative to external factors (e.g., water) nutrient information. precipitation events), results vary drastically depending on when a sample was taken. Silica data provided by ODEQ were frequently The “snapshot” quality of these short-term limited by the sensitivity of laboratory analy- data sets can sometimes limit our overall sis techniques. Therefore, many of the silica sense of the status of water quality in the data are listed as “below levels of detection” Coos estuary. However, some short term data and provide little quantitative information. collection is still important because it can provide information about parameters under Bacteria: There were limited data available to the most relevant conditions. For example, assess the Coos River, North Slough and Pony ODEQ’s storm-related bacteria monitoring is Slough subsystems.