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This appendix contains an example of a Standard Operating Procedure (SOP) developed for field sampling conducted for FHWA during the development of this manual. Due to the objective of this field work, duplicate sampling equipment was used at this site. Typically only one set of equipment for each function will be used at a site. This document is provided as an example SOP that could serve as a starting point for a site-specific SOP. Additional documents that should be developed prior to initiating field sampling may include:

  • Health and Safety Plan
  • Sampling Equipment Checklist
  • Stormwater Station Maintenance Log
  • Station Visit Checklist
  • Field Data Log
  • Work Permit for Confined Space
  • Set-up/Shut-down Checklist
  • Chain of Custody
  • Rainfall Station Record



This Monitoring Plan describes the approach, implementation schedule, and procedures that were used for monitoring stormwater discharges from highway runoff in Portland, Oregon. The monitoring location in Portland was selected by the project team for the Federal Highway Administration (FHWA) project titled Evaluation of Water Quality Monitoring Equipment for Measurements of the Constituents of Highway Stormwater Runoff.


C-1.2.1 Stormwater

The selected Northwest monitoring site is an Oregon Department of Transportation (ODOT) stormwater drain, located in Portland, Oregon. The sampling site is a stormwater drain pipe approximately 18 feet below ground, which is accessed through a manhole located in the Oregon Convention Center's exhibitor parking lot adjacent to an elevated section of Interstate 5 (I-5). The drainage area is approximately 23.1 acres and consists of approximately 0.96 miles of the I-5 corridor. The average daily traffic volume on this section of I-5 is approximately 100,000 cars. The drain pipe is a 36-inch concrete conduit, with a bottom slope of 0.017 feet at the monitoring point. Due to the fact that some perforated pipes drain into this system, the flow at this site may include some groundwater; however, groundwater flow is expected to be minimal because there is no observed base flow during dry weather.

C-1.2.2 Precipitation

Rainfall monitoring will be conducted on the rooftop of the three-story ODOT management building, which lies within a 1/2 mile of the stormwater monitoring site. Unlike the stormwater monitoring site that is situated below an elevated highway, the ODOT building offers an excellent location for precipitation monitoring. The roof of the building is flat and has no significant obstructions to interfere with the measurement of rainfall.


The objectives of the work performed at the Northwest monitoring site are as follows:

  • evaluate the installation and operation of state-of-the-art water quality detection and sampling equipment for use in characterizing highway stormwater runoff quality;
  • evaluate the operation and necessity of auxiliary equipment, such as rainfall instrumentation and flow measurement devices, with regards to monitoring stormwater quality;
  • assess the effect of climatic and other physical conditions of the site on sampling equipment and sampling methods; and
  • formulate recommendations for installation and adaptation of stormwater sampling equipment.


Highway stormwater monitoring will be conducted at the Northwest site using previously selected equipment. The equipment will be installed at the site and modifications to the equipment will be made as necessary to conduct sampling and monitoring. The equipment performance and sampling methodologies will be qualitatively assessed during the sampling of three storm events. Additionally, consideration will be given to methods for collecting and shipping samples for analysis of constituents that require special handling.


The monitoring conducted at the Northwest site will result in a constituent characterization of the site's highway runoff for three storm events. The flow weighted composite samples obtained from two automated samplers will be tested for the parameters listed in Section C-9. Individual bottles will also be analyzed for key parameters to provide insight on the "first flush" effect with regard to highway runoff. In addition to this water quality data, the in situ YSI 6000 meter will provide an almost continuous picture of the stormwater's dissolved oxygen, pH, turbidity, conductivity, temperature, salinity, and total dissolved solids. It is expected that the YSI meter will show how the values for these specific water quality parameters change over the duration of a storm event, which may indicate the variability of the parameters.

Data for this site's flow meters will also be obtained, which will aid in the comparison of the two flow monitoring units. Based on preliminary data received, this project expects that the ISCO flow monitor, using Manning's equation, will provide slightly more accurate results than the area velocity method employed by the American Sigma flow meter. This expected performance would not be verified during the field monitoring because the true flow in the drain pipe will not be known. It will be possible, however, to compare whether the two measurements display the same general relationships as in the USGS study (e.g., one method consistently records smaller peak flows).

The precipitation monitoring station will provide initial data for comparing the performance of the two rain gauges with respect to wind conditions. The optical rain gauge is expected to be more accurate than the tipping bucket under most wind conditions. This project will attempt to identify wind conditions that significantly affect the performance of the tipping bucket gauge.

Possibly the most useful information obtained from the monitoring of the Northwest site will be qualitative data obtained during monitoring. This information could include:

  • problems encountered with equipment installation;
  • reliability of equipment during operation;
  • maintenance required to maintain equipment readiness;
  • common problems encountered with storm monitoring; and
  • an indication of the parameter variability in flow-weighted composite stormwater samples collected from side by side collection equipment.

This information will be essential in assessing the performance and practicality of the stormwater monitoring equipment tested in this project.



A listing of FHWA monitoring equipment that will be used or installed at the monitoring location is provided in Table 2-1.

Equipment Manufacture Description
  • 6700 Portable Samples
  • Samplink Software w/Manual (2)
  • Wall Battery Charger
  • Lead Acid Battery (2)
  • Rabid Transfer Device (RTD)
  • RTD Power Cable
  • Four Sets of 1.8 Liter Glass Bottles
  • Low Flow Strainer
  • Pump Tubing (5)
  • Flowmeter/Interrogation Cable
  • Equipment Platform
  • Desiccant Bag
American Sigma
  • 900 Max Portable Sampler
  • Gel Battery (2)
  • Charger Assy.
  • 1.9 Liter Glass Bottles (32)
  • Retainer for 8-Bottle Configuration
  • Distributor Arm Assy.
  • 100" Teflon Lined Tubing (3/8" ID)
  • Low Flow Strainer
  • Remote Pump w/Cables and Tubing Kit
  • Streamlog II Software
  • DTUI Assy.
  • 4-20 mA Interface
  • Multi-Purpose Cable
  • Sampler - PC Cable
  • 15" to 42" Mounting Band (2)
  • Suspension Harness - Sampler
  • Desiccant - Sampler
  • Manual - Sampler
Norton Plastics Norwell Teflon Lined Tubing, 250 ft.
  • Bubbler Flow Module
  • Bubbler Line, 25'
  • Bubbler Tube Extension
  • Flow Data Book
  • Manual - Flow Meter
American Sigma
  • 950 AV Flow Meter
  • Probe/Bubble Tube Cable
  • Flow Meter - PC Cable
  • Suspension Harness - Flow Meter
  • Power Relay w/Cable
  • Desiccant - Flow Meter
  • Manual - Flow Meter
  • 600 Final Assy.
  • 6030 Probe DO/Cond/Temp
  • 6031 pH Probe Kit
  • 6063 Cable, PC Interface
  • 6035 Reconditioning Kit
  • 6026 Turbidity Probe
  • 6040 Maintenance Kit
  • Carrying Case
  • Data Logger 555A
  • 555 Software
  • Universal Mounting Hardware
  • Voice Modem
  • Modem Assy.
  • Internal Battery
  • Cable Assy.
  • Data Acquisition, Programming, and Software Manual
  • Solar Panel Assy.
Scientific Technology, Inc. Model: ORG-115-DA Optical Rain
American Sigma Tipping Bucket Rain Gage
  • 453 Wind Speed/Direction Sensor
  • Cable Assy. 30'
Masterflex Pump
  • Low Voltage (DC) Motor 1/2 hp.
  • Pump Head Adapter
  • Short Shaft Pump Head
  • Tubing size 82 (2)
Cargo Trailer 10'x4'x6' Enclosed Trailer
API-LIRCO 100 NTU Turbidity Standard
Dell Latitude XP Notebook Computer 100 MHz, DX4, 8MB RAM, 540 MB Hard

C-2.1.1 Rain Gauges

The station will be equipped with two different types of rain gauges: tipping bucket (American Sigma) and optical (Scientific Technologies, Inc.). The tipping bucket is a commonly used rain gauge that measures the rainfall volume in 0.01-inch increments. The optical rain gauge represents the cutting edge of precipitation gage technology. This gauge measures rainfall intensity (rate) and is typically used when high resolution and accuracy is required. A dedicated data logger will record data from these gauges at selected intervals (5 to 15 minutes).

C-2.1.2 Flow Monitoring Hardware/Software and Equipment Control

At the monitoring site, both flow meters (ISCO and American Sigma) will measure the depth of flow using bubbler technology. In the case of the ISCO sampler, the flow is calculated using the measured water depth and Manning's equation. In addition to measuring depth, the American Sigma 950-AV flow meter will also measure the peak velocity. The 950-AV computes the flow as the cross-sectional area multiplied by the average velocity. The cross-sectional area of water is obtained from the measured water depth and the geometry of the pipe. The average velocity is based on 90% of the peak velocity.

Each flow meter has site-specific software for hardware control. This software interfaces with the manufacturer's software installed on a laptop computer. This enables flow monitor operation to be programmed during a storm event and expedites data retrieval. Each flow monitor unit will be programmed to send a signal to activate the water quality sampler when a redefined cumulative volume of flow is exceeded.

C-2.1.3 Water Quality Samplers/Monitors

The monitoring station will be equipped with two automatic water quality samplers, an ISCO and American Sigma, each of which can be configured for either discrete or composite sampling. For stormwater monitoring, the samplers will be configured to fill sample bottles for composite sampling by collecting samples per calculated flow volumes.

The ISCO system consists of the 6700 Sampler with eight 1.9-liter glass bottles, distributor arm and bottle carrier/insert in a standard 19.875-inch wide base. Options included with the water quality sampler are a lead acid battery, a 120V AC battery charger, Teflon (3/8-inch ID) suction line and a low flow suction strainer.

The American Sigma 900 Max portable water quality sampler is equipped with a rain gauge input, a 3-channel data logger, and a remote pump receptacle. It will be assembled with eight 1.9-liter bottles, a bottle retainer and distributor arm. Options for this unit consist of a gel-cell battery and charger, Teflon (3/8-inch ID) suction line with low flow suction strainer, and a remote pump assembly.

One in situ water quality monitor (YSI 6000) will be used. The YSI 6000 is capable of continuously measuring, deriving, and logging dissolved oxygen, pH, turbidity, conductivity, temperature, salinity, and total dissolved solids data. The base unit (sonde) is equipped with various probes for monitoring specific parameters. Some of these sensors must be kept submerged in water at all times. A pump and reservoir system has been designed for the site to ensure that the probes are immersed in water even when no base flow at the site exists. After the storm event starts and flow enters the drain pipe, the pump is triggered and stormwater is pumped to a reservoir. The sonde will be immersed in the reservoir and will monitor the pumped stormwater.


The installation of equipment will occur at two sites, the Portland stormwater monitoring location and the roof of the ODOT management building. The installation plan for these two sites is described below.

C-2.2.1 Stormwater

The automatic water quality samplers (an ISCO 6700 portable sampler and an American Sigma 900 Max portable sampler) will be installed above ground in an equipment trailer. A 3/8-inch diameter Teflon suction line for each sampler will be installed in the stormwater drainage conduit. The ISCO flow module and American Sigma 950 AV Flow Meter will also be located in the trailer. The ISCO bubbler probe and Sigma velocity probe will be installed in a location that provides the most stable hydraulic conditions within the drainage pipe. Typically, the most ideal location is just upstream from the location of the manhole, because construction of the manhole may have altered the original shape of the pipe at this point, thus changing the hydraulic characteristics of the channel.

The sensor installation consists of mounting the depth and velocity sensors from the two flow units to expansion rings, which are sized and expanded in the pipe for a tight fit. The expansion ring facilitates easy removal of the sensors for maintenance or movement to another site. The water sampler intake tubing and strainer will be mounted at the invert of the pipe just downstream of the sensing equipment ring.

The YSI 6000 sonde will be inserted in a reservoir system that is mounted along with a small peristaltic pump to a platform that is suspended in the manhole access pipe. A peristaltic pump will supply stormwater via a ½-inch diameter Teflon tube to the inner reservoir where the water quality parameters will be measured by the YSI 6000 sonde. Based on the pump size (approximately 1.5 gpm) the residence time of the inner reservoir will be around 30 seconds. The inner reservoir will be allowed to overflow into the outer reservoir, which will drain back via a ¾-inch hose to the stormwater drain. The intake tubing for the pump will be mounted in the storm drain conduit with the water sampler intakes. The pump supplying water to the YSI meter will be activated, when flows are sufficient, by a relay switch located in the American Sigma flow meter. Four deep cycle marine batteries contained in the equipment trailer will supply power for this pump.

C-2.2.2 Precipitation

The precipitation gauges and wind sensor will be mounted to a plywood base using 1-inch water pipe. An equipment enclosure housing the Handar 555 data logger will also be mounted to the platform. This data logger unit will be wired and set-up to receive input from both rain gauges and the wind sensor. The entire rain and wind monitoring station will be anchored to the roof of the ODOT management building.


Calculation of flow in the closed conduit is based either on the depth of flow, or the depth and velocity of flow. To verify sensor readings both depth and velocity of flow are tested upon installation by means independent of the flow sensor. Depth measurements are verified with a scaled wading rod or similar device. In order to verify and adjust the velocity sensor, concurrent measurements are taken with a hand-held electromagnetic velocity meter.

The YSI meter will be calibrated against standards provided with the sensors. The reservoir that will provide the measurement point for the unit will be filled with water and installed in the reservoir after the unit is calibrated.

During installation of the rain monitoring station, the tipping bucket gauge will be calibrated to tip after 0.01 inch of water has accumulated in the tipper cup. The gauge will be adjusted using a graduated cylinder to measure and pour the exact water amount necessary into the gauge to initiate a tip. Both sides of the tipping cup will be calibrated in this manner.


Stormwater sampling personnel have been organized in a linear manner to form a chain of command. The links in this chain consist of: 1) Task Manager; 2) Storm Event Coordinator; and 3) Field Team members, which include a Team Leader and an Assistant. Figure 3-1 shows the overall organization of the stormwater personnel. The responsibilities for each of these positions are given below.


Task Manager. The Task Manager finalizes decisions regarding storm selection and allocation of personnel resources and has overall responsibility for all stormwater sampling.

Storm Event Coordinator. The Storm Event Coordinator is responsible for programming and operating the flow monitoring equipment, tracking and directing Field Team activity, and coordinating with the laboratory. The Storm Event Coordinator must be available to answer technical questions from the field crew during an event and must ensure that field crews have all of the necessary equipment.

Field Team Leader. The Field Team Leader is responsible for station set up, sample collection (grab and composite), station shut-down, transporting the samples to the laboratory, and completing all applicable documentation (logs, checklists, etc.). They are to be assisted by the Field Team Assistant.

Field Team Assistant. The Field Team Assistant provides support to the Field Team Leader.


Field teams are responsible for the following tasks:

  • field equipment and sample bottle organization;
  • sampling station set up;
  • basic equipment maintenance;
  • sampler programming and operation;
  • field measurement of water quality parameters;
  • grab sample collection;
  • composite sample collection;
  • bottle replacement (when necessary);
  • record keeping and field notes;
  • field Quality Assurance and Quality Control; and
  • sample labeling and transfer to the analytical laboratory

Listed below are some general procedures that must be followed when working on this project. Additional details on each of these procedures are located elsewhere in this manual.

  1. All field personnel must wear hard hats, traffic vests, and steel-toed boots when outside the vehicle.
  2. Traffic control must be set up before conducting any work at a sampling site where personnel are exposed to traffic. Standard traffic control measures include parking vehicles to shield personnel from traffic and using hazard lights.
  3. All manholes must be checked with a 4-gas meter (oxygen, methane, carbon monoxide, and hydrogen sulfide) before opening and while working within manholes.
  4. Manhole covers and samplers containing full bottles can be very heavy. Personnel must be careful when lifting to avoid injury and spilled samples (i.e., keep back straight and lift with legs).
  5. Station logs, data sheets, and checklists must be completed prior to leaving the sites.
  6. All electronic equipment should be kept as dry as possible.
  7. The person who is assigned to be the field leader will be responsible for answering the phone and making phone calls. Therefore, the assistant should be responsible for all of the driving.
  8. All field personnel will comply with the Health and Safety Plan for the FHWA project.

This manual contains instructions for operating equipment used in the FHWA Stormwater Program. It is the responsibility of URS to update this manual as changes are made in the equipment or standard operating procedures.


This section describes the chain of events that must take place prior to water quality sampling of a storm event at the Portland stormwater monitoring site. An objective of the FHWA project is to monitor three storm events within a two-month period at each of the four monitoring locations. Criteria for selecting storm events that will be monitored are provided in this section along with a method for forecasting the runoff produced by the storm.


Frequency and timing of sample collection depends upon how the data will be used. This project has two unique objectives: to learn more about the nature of highway stormwater runoff, and to assess various monitoring equipment technologies. Because of these objectives and the short monitoring period (two months), the period between monitored storm events will be shorter than would normally be used in a long-term stormwater monitoring project.

Storms will be considered for sampling if they are forecast with a 70% or greater confidence by the National Weather Service in Portland to produce a minimum of 0.30 inches of rain in an 8- to 24-hour period. Further, the storm must have been preceded by a 24-hour dry period of 0.1 inch of rain or less.

Weather conditions will be monitored daily by the Storm Event Coordinator. If a forecast suggests that a storm satisfies the selection criteria, the Storm Coordinator will recommend to the Task Manager that the field team be mobilized for station set-up and monitoring. The Task Manager will decide based upon the size, certainty, and timing of the storm whether monitoring of the event will be conducted.

It is the intent of this project to monitor three storms at the Portland site that meet the criteria listed above. However, due to the short time frame for monitoring at the site these criteria may be adjusted if weather conditions dictate, in order to reach the overall goal of monitoring three storm events.


Runoff volume estimation is necessary before monitoring to program the sampling equipment to collect representative flow-weighted composite samples. The runoff volume for the catchment is determined from the predicted rainfall amount, watershed area, and the runoff coefficient. The runoff coefficient is defined as the fraction of the total rainfall volume (the amount of rainfall over the watershed area) that becomes stormwater runoff. In general, runoff coefficients are approximately equal to the percent impervious area. The runoff coefficient used for the Portland site is 0.2.

The Storm Event Coordinator will estimate the storm's runoff volume, which will be used in programming the water quality samplers. The Field Crew will program the samplers to collect a sample after each time approximately 5% of the runoff volume has passed by the sensors. Therefore, the water quality sampler is programmed to collect about 20 samples over the entire storm. Each time the sampler is triggered to collect a sample a pre-specified volume of stormwater will be deposited into one of the bottles. If the storm is larger than expected, full bottles in the samplers may need to be replaced with empty bottles.


Mobilization of the Field Team will be made as soon as possible after a storm is selected for monitoring. The Field Team will assemble at the URS warehouse and assemble the necessary equipment for monitoring.

Each Field Team Leader must complete the Sampling Equipment Checklist before leaving the warehouse. This check confirms that all equipment is available and in proper working order. Only a calibrated gas meter may be used. The calibration procedure for the meter is located in the warehouse.

Prior to arriving at the station, the Field Teams must purchase ice. One standard 5-pound bag (available at convenience markets) is required for each sampler. Two additional bags will be required for the grab sample coolers.

The storm coordinator is responsible for making sure that all of the necessary bottles are available prior to the event. This may involve contacting the analytical laboratory and making arrangements for bottle delivery to the URS warehouse.



C-5.1.1 Accessing Samplers

The composite samplers must be accessed whenever the bottles are loaded or removed and whenever the sampler is programmed. The samplers are stored in the locked trailer next to the manhole. Access is gained by unlocking a padlock and opening the rear door of the trailer. The samplers do not need to be removed from the enclosure to perform the sampling activities. The trailer houses the ISCO 6700 Portable Sampler, American Sigma 900 Max Portable Sampler, and the American Sigma AV-950 area velocity flow meter.

C-5.1.2 Sampler Inspection

Once the samplers have been accessed, they should be inspected for typical problems and programmed for sampling. The Storm Event Coordinator is responsible for scheduling the field work such that the field crews can visit each site two to six hours before the storm event. Field crews are responsible for completing the Stormwater Station Maintenance Log for each sampler and performing basic maintenance, if necessary. The steps involved in the inspection process include:

  1. Gaining access to sampler as described in Section C-5.1.1.
  2. Checking the intake tubing for kinks or twists and clamps for tightness and condition.
  3. Checking all electrical connections for tightness.
  4. Inspecting the sampler humidity indicator located on the control panel.
  5. Checking the pump tubing for cracks and working out any pinches or replacing the tubing.
  6. Performing any required basic maintenance and completing the Stormwater Station Maintenance Log.

C-5.1.3 Sampler Bottle Loading/Replacement

Although loading bottles into the sampler is relatively simple, it is crucial that no mistakes are made. To avoid mistakes, field crews must strictly adhere to the Station Visit Checklist. The steps involved in loading (or replacing) composite sampler bottles are as follows:

  1. Gain access to sampler and perform maintenance check.
  2. If replacing bottles, obtain clearance from Storm Event Coordinator before halting sampler program or removing any bottles from the sampler.
  3. Remove sampler control section from base section by releasing the three latches on the sampler body and lifting upward using the handles. Set this assembly aside, being careful not to twist or entangle the intake tubing and electrical cables.
  4. Place eight clean 1.9 liter glass sample bottles w/lids (lids will be removed later) in base, being careful to align the middle of the first bottle with the first bottle indicator on the inside of the sampler base.
  5. Attach the retainer assembly to secure the bottles.
  6. Fill the base with crushed ice, one 5-pound bag.
  7. Remove sample bottle lids as the sampler control section is replaced. It is suggested that one person hold the control section a few inches over the base section while another person reaches into the base and removes each of the lids. The person removing lids should have clean nitrile gloves to minimize contamination of clean sample bottles.
  8. Put bottle lids in a clean zip-loc bag. Place the zip-loc bag on top of the crushed ice in the center of the sampler base. Be sure that the zip-loc bag does not interfere with the sampler distributor arm or obstruct the bottle openings.
  9. Latch control section to base section.
  10. Complete the applicable sections of the Station Visit Checklist. If making a bottle replacement, complete the applicable sections of the Field Data Log.

C-5.1.4 Sampler Programming and Operation

Both the ISCO and the American Sigma samplers are programmed to collect 24 - 600 ml samples and deliver them to 8 - 1900 ml bottles. Each bottle receives three consecutive samples before the sampler begins to fill the next bottle. The ISCO sampler receives its triggers on a flow-weighted basis from a calculation the sampler unit performs. The ISCO sampler is equipped with a bubbler flow module that measures depth of flow in the pipe, which allows the sampler to calculate the flow rate using Manning's equation. The American Sigma sampler receives its flow-weighted triggers from a 950-AV (area-velocity controller), which is a separate unit housed in the trailer. The 950-AV uses depth of flow, velocity, and pipe geometry to calculate a flow rate in the pipe.

The samplers and 950-AV must be properly calibrated and programmed in order to successfully collect a full set of composite stormwater samples. Field Teams will be responsible for checking the sampler's calibration, reviewing program parameters, and making sure that the program is running each time a sampler is visited.


C-5.2.1 Accessing the YSI System

Between monitored storm events, the YSI sonde and four 6-volt deep cycle marine batteries that provide 12 volts of power for the pump that supplies water to the YSI sonde reservoir are stored in the trailer (the YSI sonde should be stored in its protective case). Both the trailer and the manhole will need to be accessed to set up the YSI sonde for operation. Prior to accessing the manhole, field crews must complete a Work Permit for Confined Space.

C-5.2.2 YSI System Inspection

After gaining access to the trailer and the manhole, several YSI system components need to be inspected prior to calibrating the meter and installing it in the manhole. Field crews should conduct the following:

  1. Install in the trailer the four, charged pump batteries. Connect the power leads for the YSI pump to the batteries.
  2. Visually inspect the pump wiring in the trailer for cuts.
  3. From above ground, use a flashlight to visually inspect the reservoir system, pump, tubing, and electrical wiring for the YSI system components mounted in the manhole.
  4. Remove the YSI sonde from the storage case, remove the meter's calibration storage cup and inspect the probes for visual damage. Ensure the membrane over the dissolved oxygen probe is free of tears.
  5. Complete the Stormwater Station Maintenance Log.

C-5.2.3 YSI Sonde Calibration and Operation

The YSI sonde is equipped with three probes to measure conductivity, pH, turbidity, and dissolved oxygen. It is necessary to calibrate the meter for all of these measurements prior to sampling a storm event. To calibrate the meter, follow the general steps outlined below.

  1. After accessing and inspecting the YSI sonde, remove the waterproof cap from the sonde connector and connect the PC interface cable. Connect the DB-9 end of the cable to a serial port on the laptop computer.
  2. Remove and retain the two allen screws at the very bottom of the sonde guard. Remove the bottom plate of the sonde guard (not the entire guard). This allows the calibration solutions access to the probes with minimal displacement of fluid within the calibration cup. Additionally, carry-over from one solution to the next is reduced.
  3. Have 2 liters of fresh tap water readily accessible for rinsing the sonde between calibration solutions, 500 ml each of pH 4 and pH 10 calibration solution, 500 ml of conductivity standard, 500 ml of turbidity standard, and a separate liter of fresh tap water for calibration.
  4. Conduct sonde calibration according to the manufacture's instructions.

After calibration of the meter is complete, place the sonde in unattended run mode. Install the sonde in the manhole as follows:

  1. Disconnect the laptop computer from the sonde and reinstall the sonde guard that was removed in item 2 above.
  2. Ensure the sonde reservoir (mounted on the platform in the manhole) is filled with water prior to installing the sonde in the manhole. It is essential to keep the probes on the sonde wet. If the reservoir is empty, it can be filled from above using the PVC pipe and funnel located in the trailer. Do not climb down into the manhole to fill the reservoir. Once there is flow in the pipe, the pump is energized via a relay in the AV-950 flow meter to pump stormwater into the reservoir.
  3. Lower the sonde in to the manhole. Use the 25-foot PC interface cable connected during calibration and lower the meter down into the reservoir located on the platform in the manhole. Tie off the PC interface cable near the top of the manhole and reinstall the manhole cover.
  4. Complete the applicable sections of the Station Visit Checklist.

The YSI meter should now be in operation. It will not begin to record parameter measurements for stormwater until there is water in the pipe and the pump changes out the water in the reservoir.



After calibrating and placing the ISCO and American Sigma samplers in run mode, both units will collect samples from the stormwater drain automatically when the pre-defined trigger volume is exceeded. Provided there is sufficient flow in the drain pipe and the samplers do not malfunction, each sampler should collect and distribute a total of 24 - 600 ml samples among the eight 1.9 liter sample bottles contained in the base of the sampler. Bottle one in the sampler will be filled with the first three 600-ml samples collected (samples 1, 2, and 3). Bottle two will be filled with the next three 600-ml samples (samples 4, 5, and 6). The remaining six bottles will be filled following the same sequence. If the storm is short or if there are mechanical problems with the sampler, some bottles may not be filled.


Grab samples will be collected for the analysis of oil and grease and petroleum hydrocarbons. The collection of grab samples is necessary for assessing the presence of oil and grease because these constituents float on the surface of the water. The amount of oil and grease in the stormwater would be underestimated if the samples collected by the automated samplers were used for analysis because the automated samplers collect samples near the invert of the drain pipe.

C-6.2.1 Grab Sample Collection

Grab samples will be collected directly into a large-mouth 1-liter amber sample bottle. Two 1-liter samples will be collected approximately one hour after the start of the storm event. Follow the general procedures for sample collection outlined below:

  1. Insert the sample bottle into the protective grab sample harness and remove the bottle lid.
  2. Connect a rope to the sample harness and lower the harness and bottle into the pipe/channel to collect the stormwater from mid-channel at mid-depth.
  3. Collect both 1-liter samples in this manner and complete applicable sections of the Field Data Log.


The measurement of chemical constituents at the trace level is often difficult due to inherent properties of environmental samples, field sampling techniques, and analysis techniques. In order to assess and maximize data quality, a strict Quality Assurance and Quality Control (QA/QC) Plan will be implemented as an integral part of the monitoring program. The QA/QC program is designed to enable an evaluation and validation of the analytical data for representativeness, accuracy, and precision. The following text includes separate descriptions for the field and laboratory portions of the QA/QC program.


Field QA/QC samples will be collected for one storm event to be determined by the Storm Event Coordinator. QA/QC samples require special labeling and tracking procedures. All duplicate samples will be treated as "blind field" duplicates, which are given a fictitious station identification and collection time. Therefore, it is very important to record the true duplicate station location and collection time on the Field Data Log. All equipment blanks will be labeled as "equipment blanks." The specific field procedures for conducting these tests are presented as follows.

Equipment Blanks - Composite sampler equipment blanks will be obtained by letting the sampler fill a complete set of bottles with clean de-ionized (DI) water. One set of blanks will be collected for each sampler during one storm event. Equipment blanks will be collected during set up, prior to the beginning of the storm event. This process is detailed below:

  1. Access the sampler, complete inspection, and check calibration.
  2. Detach the intake tubing from the sampler and attach a short piece of new or de-contaminated Teflon-lined tubing to the pump tubing and rinse the system for at least 15 seconds with DI water using the sampler pump.
  3. Load the sampler with sample bottles.
  4. Fill each sample bottle with DI water by pressing "pump sample" 3 times. Move to the next bottle by pressing "bottle advance." Label sample bottles as "equipment blanks."

Duplicates - Grab sample duplicates will require one of the Field Teams to fill an additional set of grab sample bottles during one storm event for QA/QC. These bottles will be labeled with a fictitious site identification and/or time. Record true location and/or times in the Field Data Log. This duplicate sample will be analyzed to assess sampling and analytic precision.


The laboratory contracted will perform all chemical analyses requested. In addition to performing the analysis, the laboratory will make every effort to meet holding times and target detection limits for each analysis. The following laboratory QA/QC procedures will be followed for the sampling program.

Standards - Calibration standards with known concentrations will be prepared and used in the laboratory to obtain instrument calibration curves in accordance with the provisions of the various method specifications.

Method Blanks - Analyte-free water will be processed through all sample preparation procedures and analyzed as a method blank. One such method blank will be analyzed per storm event. This will provide an indication as to whether contamination is occurring as a result of laboratory procedures.

Replicates - The laboratory will perform replicate sample analysis twice for each sampler. The Storm Coordinator will determine the analysis sequence. The intention will be to have a replicate analyzed from each of four sampling sites designated in Task B of the project. Replicate samples are two aliquots taken from the same sample container and analyzed independently. After compositing at the analytical lab, the total sample volume will be divided equally in half and each half will be analyzed separately. Because the laboratory must composite the samples before dividing, this is not a blind replicate.

Matrix Spike - For metals analysis, the laboratory will perform a matrix spike to provide a measure of accuracy for the method used in a given matrix. A matrix spike analysis is performed by adding a predetermined quantity of stock solutions of certain analytes to a sample matrix prior to sample extraction/digestion and analysis.


Results of precision and contamination checks (described above) will be reviewed by a chemist after each storm event. Summary results of the QA/QC program will be included in the storm reports (see Section C-11). In the event that data quality objectives are not met, data will be qualified as necessary in the final data report.



When the Storm Event Coordinator makes the final determination that storm sampling is complete, Field Team(s) will perform station shut-down and other post-storm procedures. The station shut-down procedures include the following tasks:

  1. Remove and label sample bottles from the samplers. These samples will be grouped with the rest of the composite bottles and taken to the analytical laboratory for analysis.
  2. Record the number and timing of samples taken by the sampler on a Field Data Log.
  3. Download all storm data to the lap top computer following the data retrieval instruction for the YSI Sonde, the ISCO sampler and American Sampler, and flow meter.
  4. Remove the PC data cable and properly stow the sonde in its calibration cup and protective case after retrieving the data from the YSI sonde.
  5. Remove the batteries from the samplers and the trailer. Transport the batteries to the warehouse and set-up for charging.
  6. Complete the shut-down section of the Set-up/Shut-down Checklist.
  7. Organize all completed field sheets and checklists and transfer them to the Storm Event Coordinator. Teams will be required to submit the following items:
    1. Sampling Equipment Checklist
    2. Work Permit for Confined Spaces (manhole stations only)
    3. Stormwater Station Maintenance Logs
    4. Station Visit Checklist
    5. Field Data Logs
    6. Chain of Custody Forms


Field Team Leaders are responsible for the labeling and transfer of samples from the field stations to the analytical laboratory. The bottles must be securely packed with blue ice in coolers for shipment to the lab facility. The transfer process involves the completion of Chain of Custody sheets.

C-8.2.1 Sample Labeling

Sample labels must be filled out completely. The following information should be entered on every label:

  1. Date and time collected (24-hour clock using Pacific Standard Time).
  2. Station identification (I01 for ISCO & S01 for Sigma).
  3. Total number of sample bottles for each analysis and the number of each container (e.g., 1/ 8, 2/ 8, etc.).
  4. Initials of Field Team.

Note: The sample information should be written on the label before applying it to the bottle. Also, the bottle should be dried with a paper towel before applying the label.

C-8.2.2 Chain of Custody

The Chain of Custody sheets track the sample containers and specify how the sample is to be analyzed. Field crews will use a Chain of Custody form provided by the analytical laboratory to record the necessary information. The analytical laboratory will not accept any samples without a completed Chain of Custody form.

The following organizational scheme has been developed to minimize confusion during the sample Chain of Custody process:

  1. Each Field Team Leader will check the bottle labels and assemble all samples in an orderly manner.
  2. Each Field Team Leader will complete the Chain of Custody forms.
  3. The Field Team Leaders and/or Storm Event Coordinator will then ship via Federal Express each set of sample bottles in a cooler with the appropriate Chain of Custody Form to General Testing at 710 Exchange Street, Rochester, NY 14608.


This section of the monitoring plan provides a general description of parameters to be analyzed in stormwater samples and the methods used by the lab for the analysis.


The laboratory will perform testing on three different sample types: individual bottle samples, grab samples, and composite samples.

Individual bottle analysis consists of drawing a sample from each of the eight bottles for both samplers and analyzing that sample for a select group of parameters commonly found in highway runoff. This analysis will provide information on how constituent concentrations change over the course of the storm event.

The water remaining in eight bottles from the ISCO sampler will then be composited in a glass container, and the water remaining in eight bottles from the American Sigma sampler will be composited in a separate container. The composite samples for each sampler will be analyzed for a set of parameters that are more extensive than the analysis performed on the individual bottles. This analysis will provide the study with a storm average of parameter concentrations.

The collected grab samples will be analyzed for oil and grease (O&G) and total petroleum hydrocarbons (TPH). O&G represents a broad group of pollutants including animal fats and petroleum products. TPH is the subset of O&G that represents the non-polar hydrocarbons from petroleum products (e.g., gas and engine oil for automobiles).

C-9.1.1 Parameters and Methods for Analysis

Table 9-1 provides a list of the parameters to be analyzed for each sample type along with USEPA analysis method used, the target detection limit, cost to perform the analysis, and the maximum holding time for the parameter. The total laboratory costs for monitoring the three storm events in Portland is estimated in Table 9.1 to be $3,500. This includes costs for QA/QC, shipping, and bottle cleaning.

4 ppm
7 days
1 ppm
6 months
Phosphorus, Total
0.05 ppm
28 days
Kjeldahl Nitrogen, Total
0.1 ppm
28 days
Nitrate + Nitrite
0.05 ppm
48 hours
0.1 ppm
28 days
Cadmium (total & dissolved)
0.2 ppb
6 months
Cooper (total & dissolved)
1.0 ppb
6 months
Lead (total & dissolved)
0.2 ppb
6 months
Unit Cost per Sample per Event
Extended Cost per Event
Cost per Site (3 events)
Oil & Grease
0.5 ppm
7 days
0.5 ppm
7 days
Cost per Event
Cost per Site
4 ppm
7 days
1.0 ppb
6 months
Cost per Bottle
Cost per Event (16 bottles)
Cost per Site (3 events)

Total Costs for Sampling at a Site  
QA/QC $500
Shipping $500
Cleaning 6 sets of Bottles $150
Individual Bottle Analysis $1,037
Grab Samples Analysis $216
Composite Sample Analysis $1,139
Total Laboratory Costs $3,542


Total Suspended Solids (TSS) - Rivers and streams in their natural state carry sediment loads. The conditions under which suspended solids are considered a pollutant are a matter of definition. In general, suspended solids are considered a pollutant when they significantly exceed natural concentrations and have a detrimental effect on water quality and/or beneficial uses of the water body. Portions of the suspended solids will settle out of the water column depending on the size of the particle and the velocity of the water. These settled solids can blanket the bottom of water bodies and damage invertebrate populations; cover gravel spawning beds; clog the gill structures of young trout and salmon; change the pattern of the channel; and in some cases lead to the reduction of channel capacity. Suspended sediments may also result in stress to fish by causing alterations in behavior and movement patterns because fish will often avoid turbid areas. Sediment that remains suspended in the water column diminishes light penetration into the water body, reducing the depth of the zone where primary production occurs and hence reducing the amount of food available for fish. Suspended sediments near the surface can also cause an increase in water temperature because they have a greater tendency to absorb heat, they scatter light (as measured by turbidity), and they reduce water clarity. Both suspended and settled solids are also of concern because they are associated with toxins (toxic metals and organics tend to sorb onto particulate matter).

In addition to natural erosion, sources of sediment can include runoff from construction sites, agricultural activities, logging activities, and any other operations where the ground surface is disturbed. Increased flows resulting from development are also responsible for erosion in excess of natural background levels.

Hardness - Hardness is a measure of specific types of ions that are dissolved in water. In fresh water it is usually defined as the sum of the calcium and magnesium concentrations. It is important in stormwater because the biological availability, and therefore toxicity, of some metals is directly related to the hardness of the water. For example, the freshwater acute and chronic criteria for cadmium, chromium, copper, lead, nickel, silver, and zinc are hardness-dependent. When hardness values are relatively low, the bioavailability of these metals is relatively high.

Phosphorus - Phosphorus is used as a nutrient by algae and higher aquatic plants, and excess may be stored for use within plant cells. With decomposition of plant cells, some phosphorus may be released immediately through bacterial actions for recycling within the biotic community, while the remainder may be deposited with sediments.

Three forms of phosphorus have been somewhat routinely analyzed in stormwater runoff water quality studies. These include total phosphorus, soluble phosphorus, and orthophosphate. Orthophosphate represents the inorganic phosphorus that is most immediately biologically available. Soluble phosphorus includes orthophosphate and a fraction of the organic phosphorus. The majority of soluble phosphorous is usually orthophosphate. Total phosphorus includes other forms of phosphorous that may not be as readily biologically available, in addition to the orthophosphate and soluble phosphorus. Total phosphorus and orthophosphate are generally recommended for inclusion in stormwater monitoring programs, however, due to the short holding time for orthophosphate (48 hours) this project has elected not to analyze for this parameter.

Nitrogen (Total Kjeldahl Nitrogen, Ammonia Nitrogen, Nitrate Nitrogen) - Nitrogen is used as a nutrient by algae and higher aquatic plants, and excess may be stored for use within plant cells. With decomposition of plant cells, some nitrogen may be released immediately through bacterial action for recycling within the biotic community, while the remainder may be deposited with sediments.

Nonpoint sources of nitrogen include fertilizers, municipal/industrial wastewater, septic tanks, leachate from waste disposal in dumps or sanitary landfills, atmospheric fallout, nitrite discharges from automobile exhausts and other combustion processes, natural sources such as mineralization of soil organic matter, and farm-site fertilizers and animal wastes.

Three forms of nitrogen have been analyzed extensively in stormwater runoff water quality studies. These are nitrite plus nitrate (NO2 + NO3), ammonia nitrogen (NH3), and total Kjeldahl nitrogen (TKN). The latter, named after the analytical test procedure, provides a measure of ammonia and organic nitrogen forms that are present. The first (NO2 + NO3) provides a measure of the inorganic nitrogen. There is usually very little nitrite in stormwater. Nitrate (NO3) is very mobile and is usually difficult to treat utilizing stormwater BMPs. Ammonia nitrogen can be toxic to aquatic life depending on the pH and temperature of the receiving water. These three forms of nitrogen are important to characterize nitrogen forms in stormwater and for conducting receiving water assessments.

Total and Dissolved Metals (Cadmium, Copper, Lead, Zinc) - Heavy metals may be washed into streams (via stormwater runoff) or they may be naturally released in small quantities by the weathering of rock. Sources of metals in stormwater runoff include combustion of fossil fuels, disposal of car batteries, tires (cadmium and zinc), brake pads (copper), metal recyclers, metal corrosion, pigments for paints, solder, fungicides, pesticides, herbicides, and wood preservatives. When metals are released into the environment in larger than "natural" or background concentrations, they can be highly toxic to freshwater aquatic species.

Information regarding the percentage of metals in the dissolved and particulate phases is useful for selecting control measures. For example, control measures designed to remove particulates from flows will not be effective at removing metals if a large portion of the metals are in the dissolved phase (or if they are sorbed to particulates that are so small that it is difficult to remove them by settling).

Heavy metals tend to have relatively low solubilities. However, they are often found in the water column as they form soluble complexes with humid materials or as they become attached to suspended particles. Heavy metals have been identified consistently as the most significant toxics found in urban stormwater and often exceed water quality criteria for aquatic life.

Stormwater quality studies conducted at many urban locations have indicated that cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) are almost always present, and are at concentrations that tend to be elevated relative to other heavy metals. They can also be used as surrogates for other heavy metals, as they tend to display the range of transport characteristics for heavy metals. However, other heavy metals should be analyzed if there are known sources of significant quantities of these metals in influent flows to the storm system.

Oil & Grease and Total Petroleum Hydrocarbons (TPH) - Oil and grease represents a broad group of pollutants including animal fats and petroleum products. Accurately measuring oil and grease is very difficult due to its affinity for coating sampling bottles and sampling tubes, and its highly non-uniform distribution in the water column (except in the most turbulent and well mixed conditions). With the proper sampling techniques and preservatives, total oil and grease can be measured. However, other tests provide more insight regarding the sources of oil and grease, including total petroleum hydrocarbons (TPH) and polar oil and grease. TPH is the subset of oil and grease that represents the non-polar hydrocarbons from petroleum products (e.g., gas and engine oil for automobiles). Polar oil and grease is the subset of oil and grease that represents polar hydrocarbons from natural organics such as animal by-products (e.g., animal and vegetable fats in refuse from restaurants). If completed, the TPH evaluation is the most appropriate measure of human induced sources of petroleum oil and greases.


This section provides the general set-up and data retrieval guidelines for the rainfall and wind monitoring equipment.


The rainfall monitoring station consists of the tipping bucket and optical rain gauges, a wind speed and wind direction sensor, and a data logger with a solar panel power supply. Field Crews will install the gauge on top of the ODOT building, as described in Section C-2. Rain and wind monitoring will be initiated upon station set up and will continue until stormwater monitoring is completed at the Portland site. Instruction for wiring and operating the Handar 555 data logger will be provided.

Field crews must visit the monitoring station weekly to download the data collected by data logger. Whenever the site is visited and the data logger is accessed the Field crew must complete the Rainfall Station Record. The field team leader will provide this form to the storm coordinator after each visit to the site.


All data collected as part of this monitoring study should be stored in electronic format for easy retrieval, data interpretation, and graphing. Data collected as part of the sampling program should include rainfall data, runoff volumes, runoff coefficients, field analytical data, laboratory analytical data, and QA/QC results.

Following each sampling event, a storm report should be prepared that summarizes the results of the sampling. This report should include the date of the storm, the antecedent dry period, the total rainfall, a description of the storm, and a description of the equipment operation. Hydrographs and trigger times and analytical data for each sampler should be included. The storm reports will provide a basis for summarizing the project results at the completion of monitoring.

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Questions and feedback should be directed to Deirdre Remley (deirdre.remley@dot.gov, 202-366-0524).

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