Continuous Water-Quality Field Methods Micelis Doyle & Joe Rinella U.S. Geological Survey &

Course Overview 4/23/08, Wednesday, 11:30 AM to 12:20 PM Description of water-quality monitors Description of parameters and their use Overview of field trip activities 4/25/08, Friday, 12:45 PM to 16:45 PM Field trip to Clackamas River at Oregon City to calibrate a water-quality monitor 4/28/08, Monday, 11:30 AM to 12:20 PM Debriefing of field work, discussion, and review of homework

Reading Assignment Guidelines and Standard procedures for Continuous Water-Quality Monitors: station Operation, Record Computation, and Data Recording (USGS Techniques and Methods 1-D3) Read pages Homework question set is due on 4/28/08

Instructions for driving to Clackamas River at Oregon City field site on Friday, 4/25/08 Meet at the site at 1:15 PM Bring clipboards and pencils See map with driving instructions If lost, call

Water Quality Water temperature Dissolved oxygen pH Major ions and specific conductance Alkalinity and acidity Erosion and sedimentation--suspended sediment and turbidity Eutrophication—nutrients (e.g. nitrate, ammonia, phosphates—not measured in the Clackamas River) Contaminants Inorganic chemicals (e.g. trace metals) Organic (e.g. pesticides and industrial chemicals) Fecal indicator bacteria Total dissolved gas Health of biota (including chlorophyll)

Types of sensors Water temperature Specific conductance Dissolved oxygen pH Turbidity Chlorophyll—free-floating algae Total dissolved gas Chemical species (e.g. nitrate, ammonia, phosphates)

Conditions that change water temperature Solar heating — seasonal/daily Thermal loss — air or streambed Inflows — Ground water or surface water Outflow — less dilution water

Conditions that change specific conductance (Measure of the capacity of water to conduct an electrical current—function of dissolved ions) Dilution (e.g. rain water runoff) Evaporation — concentrates chemicals in water Inflow/outflow Chemistry (e.g. weathering of minerals, runoff from land applications, & point sources)

Conditions that change dissolved oxygen Temperature Aeration Biological activity Photosynthesis in presence of sunlight 6 CO H 2 O  C 6 H 12 O 6 (sugar) + 6 O 2 (consumes CO 2 and produces O 2 ) Salinity Atmospheric pressure

Conditions that change pH (- Log of the hydrogen ion activity) Dissolved gas exchange Temperature change Weathering of minerals Biological activity Photosynthesis in presence of sunlight 6 CO H 2 O  C 6 H 12 O 6 (sugar) + 6 O 2 Respiration (O 2 is consumed and CO 2 is formed) CO 2 + H 2 O  HCO H +  CO H +

Conditions that change turbidity (measure of light that scatters off suspended particles) High flow events — erosion and sedimentation Inflows with different turbidity levels Stream channel disturbance Biological activity — algal production

Advantages of continuous, near real-time, water-quality data Quickly identify transmission problems Recognize erroneous data due to: Fouling Calibration drift Other problems Quickly recognize sensor or monitor malfunctions Can quickly respond to problems and optimize the quality of the data Early warning of water-quality problems

Operation of water-quality monitors includes: Quality assurance and quality control Accuracy Precision Reliability Water-quality monitor site operation Routine cleaning, calibration, and maintenance Record storage Record computations to apply data corrections Publication Archiving

Arrive at site at 1:15 PM Wait for all to arrive so that we can enter plant as a group Inspect water-quality monitor vehicle and supplies Enter plant to perform site maintenance and calibration check as group; once the group is inside, no one else will be able to enter the facility Site Visit Activities

Site Visit Activities (continued) Explanation and inspection of equipment Review initial site checks performed while servicing station Download data from data logger Note river gage height for stream discharge information Note any other station information

Site Maintenance and Calibration Compare “Before Cleaning” the water-quality monitor (WQM) readings at the site with field (portable) WQM readings in the river Remove and clean WQM at the site Return site’s WQM to conduit to obtain “After Cleaning” comparison readings with field WQM Remove site’s WQM for calibration check Calibrate site’s WQM Return site’s WQM to conduit and obtain final comparison readings