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Stormwater Monitoring location to evaluate treatment facility effectiveness. |
The Water Quality and Stormwater Program provides guidance and technical support to planning, design, construction, and maintenance offices to help WSDOT enhance project delivery and achieve compliance with the Federal Clean Water Act, and State Water Quality Laws (RCW 90.48, WAC 173-201A, and WAC 173-270).
National Pollutant Discharge Elimination System (NPDES)The 1987 amendments to the Clean Water Act (CWA) extended the
NPDES program to include stormwater discharges. The primary objective of the Clean Water Act (CWA) is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters. The NPDES permit program is the U.S. Environmental Protection Agency’s (EPA) primary enforcement mechanism to ensure compliance with the CWA’s provisions. EPA regulations require NPDES permits for discharges from four broad categories of stormwater discharges:
- Municipal separate storm sewer systems (MS4s)
- Construction activity
- Industrial activity
- Sand and gravel activity
WSDOT has permit coverage under all four of these categories.
More on WSDOT NPDES stormwater permits.
NPDES Annual Progress Reports
WSDOT submits annual reports to the Department of Ecology summarizing activities undertaken to comply with its NPDES municipal permits and evaluate the effectiveness of its stormwater management program. Previous reports are archived at WSDOT and can be made available upon request.
- 2007 Annual progress report (pdf 4.44 mb)
2005-2007 Stormwater Treatment Facility Monitoring Data
The amount of stormwater data that WSDOT collected 2005-2007 greatly surpasses the amount of data that was collected previously. Also, the amount of supporting information has also increased giving greater context and quality control documentation regarding the data. Rather than summarize and interpret the data within annual reports, the 2005-2007 data is directly posted along with supporting information so that interested parties can make their own evaluations as to the strengths, weaknesses and applicability of the data in different situations. It is important that data viewers first review the below information to better understand the data and it's limitations.
Stormwater and highways are highly variable. The following should be considered before drawing conclusions regarding the linked WSDOT data.
- This data was collected from only 13 Western Washington sites out of a highly variable 7,044-mile highway system spanning various climates and land uses.
- Infiltration-related stormwater volume losses vary widely depending on site-specific soils, drainage system configurations and pre-storm weather conditions.
- Treatment facility effectiveness is highly variable and differences between individual facilities may not reflect consistent differences between facility categories.
- Treatment facility effectiveness varies with influent pollutant concentrations and flow conditions. Pollutant removal efficiency is generally high when water entering the facility is dirty and low when water entering the facility is clean.
- Site-specific and storm-specific information must be reviewed to put runoff data in proper context.
- Statistical analysis must be properly applied to determine the significance of differences between sites or before and after treatment.
The Quality Assurance Project Plan and Addenda together provide details on how we ensure that the collected data meets our standards for quality and that sampling locations are described to help people put the data in context. The Quality Assurance Project Plan (pdf 176 KB) includes the policies and procedures to help ensure that data is accurate and representative. While originally written for the 2003-2005 monitoring period, the QAPP was also used during the 2005-2007 monitoring period with addenda to address monitoring changes that occurred each year. The addenda contain critical site-specific information to help users understand the conditions under which the water was sampled like whether or not the water receives pretreatment prior to the sampling point. Two addenda were prepared in the 2005-2007 monitoring period because different monitoring sites were selected for the first (pdf 2.72 MB) and second (pdf 1.53 MB) monitoring seasons.
Individual Storm Reports are designed to help one assess the observations associated with a single storm event. They provide detailed information about individual storms, how samples were collected and quality control concerns associated with sampling and analysis.
Data validation memos document quality control issues associated with the data sampling in the first (pdf 58 Kb) and second (pdf 64 Kb)year of monitoring. These memos document the decision made to accept, qualify or reject data based on compliance or non-compliance with storm acceptability criteria, sampling and holding protocols, or analysis standards. It is important to note that, in hindsight, the method used for collecting field replicates actually generated a form of field splits that can't be used to quantify the amount of data variability associated with drawing water into the sample bottles.
Individual Storm Reports are designed to help one assess the observations associated with a single storm event. They provide detailed information about individual storms, how samples were collected and quality control concerns associated with the samples.
WSDOT’s stormwater data spreadsheet (.xls 1MB) contains chemistry data, flow and weather information, sampling specifics in terms storm coverage, load reduction estimates and what qualifiers we apply to the data. Even with the supporting information, questions may arise regarding the data. Any questions about the data can be addressed to Richard Tveten at 360-570-6648 or Cory Simon at 360-570-2589.
Puget Sound Highway Runoff Program
In 1987, the Puget Sound Water Quality Authority issued the Puget Sound Water Quality Management Plan. This plan called for a Highway Runoff Program, which was subsequently developed by Ecology and codified in Chapter 173-270 of the Washington Administrative Code (WAC). This regulation established the basis for the management of stormwater runoff from transportation infrastructure to protect water quality in the Puget Sound basin.
Guidance, Procedures, & Tools
Stormwater Research
Stormwater management is a complex task with a variety of regulatory drivers and constraints, involving numerous technical disciplines including hydraulics, hydrology, geology, and water quality. The relatively narrow linear nature of the highway network further constrains the use of conventional stormwater management approaches while also requiring safe access for maintenance of stormwater facilities. To help meet these challenges, WSDOT relies on stormwater research to help identify state-of-the-art, cost-effective solutions for designing, constructing, and maintaining stormwater management systems.
More on WSDOT stormwater research.
Erosion & Sediment Control Program
The WSDOT Erosion Control Program prevents erosion-related cost overruns, project delays, and protects the environment by providing training, technical assistance, and guidance materials to WSDOT staff and contractors.
Stormwater Pollution Prevention Plans
The Water Quality Program can assist with the preparation and review of Stormwater Pollution Prevention Plans (SWPPPs) for Highway Construction, Ferries, Aviation, and Rail divisions.
Stormwater Facilities Inventory & Retrofits
Under WAC 173-270 (adopted in 1991), WSDOT is required to inventory, prioritize, and retrofit all stormwater outfalls. Work is currently under way to inventory over 20,000 outfalls around the state. Information will be gathered into a database and will include a thorough assessment of the conditions at each outfall. The database will then automatically generate a priority list of outfalls that require retrofit. Recommendations for retrofit best management practices (BMPs) are also included as part of the overall prioritization score for each outfall. Information from this inventory will simultaneously benefit several WSDOT operations including:
- Program management
- Design offices
- Maintenance
- Environmental offices (NPDES and NEPA)
Outfall information associated with Hydraulic Reports should be collected in accordance with the Hydraulic Staff Outfall Inventory Instructions. Enter the information into the Hydraulic Staff Outfall Inventory Spreadsheet and e-mail it to Cory Simon or Richard Tveten. Any questions about this process should be addressed to Cory at 360-570-2589 or Richard at 360-570-6648.
NEPA/SEPA Programs Support
The Water Quality Program provides the following services for the National Environmental Policy Act (NEPA) and Washington State Environmental Policy Act (SEPA):
- Water quality discipline study preparation guidance and templates
- Prepare and review discipline studies in accordance with WSDOT Environmental Procedures Manual Section 430.
Drinking Well Protection Agreement
WSDOT and the Washington State Department of Health have entered into a Drinking Well Protection Agreement to clarify expectations, establish screening criteria, and facilitate communication for projects that intersect the sanitary control area of a public water supply.
Illicit Discharge Detection and Elimination
Any dumping or pumping of pollutants or polluted water into drainage ditches or storm drains is considered an illicit discharge.
Examples of illicit discharges include:
• Muddy water from construction sites
• Chemical spills
• Industrial waste water
• Sewage leaks
• Farm animal wastes
WSDOT is required to identify and eliminate illicit discharges to prevent pollution of Washington's waters. Anyone who notices an illicit discharge can help by reporting it. If you see pollutants being spilled, pumped or dumped into a highway or rest area stormwater system, please contact the Department of Ecology at (360) 407-6300 and WSDOT at (360) 570-2589.
Underground Injection Control
Infiltration is one of the preferred methods for disposing of excess stormwater. Subsurface infiltration is regulated by the Underground Injection Control (UIC) Rule, which is intended to protect underground sources of drinking water. The UIC Rule requires WSDOT to assess and register all underground injection facilities.
Project Offices in coordination with the Region Hydraulics Offices, shall download and complete the linked spreadsheet (xls 153kb). Send completed forms to tvetenr@wsdot.wa.gov. Completed spreadsheet information will be used to register facilities.