August Report

Transcription

1 THEA FOSS AND WHEELER-OSGOOD WATERWAYS STORMWATER MONITORING August Report Prepared for: DEPARTMENT OF ECOLOGY Prepared by: CITY OF TACOMA March 2009

2 Table of Contents Page 1.0 INTRODUCTION BACKGROUND DRAINAGE BASIN DESCRIPTION GOALS Objectives MONITORING PROGRAM DESCRIPTION SAMPLE LOCATIONS FIELD SAMPLING PROGRAM Baseflow Monitoring Stormwater Monitoring Stormwater Suspended Particulate Matter Monitoring Sediment Traps and MH390 Sump RESULTS RAINFALL SUMMARY Foss 2001 SAP Seasons: Monitoring Period to Historic Rainfall Comparison Water Year Seasons: Monitoring Period to Historic Rainfall Comparison FIELD AND HYDROLOGICAL DATA SUMMARY Baseflow Monitoring Hydrological Data Evaluation Field Data Evaluation Stormwater Monitoring Representativeness of Individual Storm Events Representativeness of Storm Types Stormwater Criteria Evaluation Stormwater Suspended Particulate Matter Monitoring - Sediment Traps and MH390 Sump DATA SUMMARY Data Appendices Summary Statistics Constituents of Interests STATISTICAL EVALUATION OF WHOLE WATER DATA Baseflow Quality Qualitative Assessment of Temporal and Spatial Charts Nonparametric ANOVA (Kruskall Wallis Test) Nonparametric Post-Hoc Comparison (Dunn Test) Stormwater Quality Qualitative Assessment of Temporal and Spatial Charts Statistical Distribution Tests Power Analysis Parametric ANOVA Parametric Post-Hoc Comparison (Tukey Test) Stormwater Time Trend Analysis Seasonal Kendall Test Regression Analysis Comparison of Baseflow and Stormwater Quality ANALYSIS OF STORM SEDIMENT... 37

3 Table of Contents (Cont d) Page 4.0 CONCLUSIONS INTRODUCTION IDENTIFICATION OF CHEMICALS OF CONCERN Total Metals PAHs Phthalates Pesticides and PCBs TPH RECOMMENDATIONS RECOMMENDATIONS FOR FOSS 2001 SAP REVISIONS PROPOSED REVISIONS TO SAMPLING AND ANALYSIS PROTOCOLS PROPOSED REVISIONS TO STATISTICAL EVALUATION PROCEDURES Statistical Analyses Recommended for Continued Use Statistical Analyses to be Discontinued REFERENCES Figures Figure ES-1 Chemicals of Concern by Outfall Figure 1 Thea Foss and Stormwater Outfalls Figure 2 Sediment Trap Thea Foss Waterway Figure 3a Year 1 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3b Year 2 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3c Year 3 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3d Year 4 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3e Year 5 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3f Year 6 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 3g Year 7 Daily Rainfall and Average Daily Rainfall 21 Day Trends Only Figure 4a Year 1 Daily Rainfall Monthly Averages Figure 4b Year 2 Daily Rainfall Monthly Averages Figure 4c Year 3 Daily Rainfall Monthly Averages Figure 4d Year 4 Daily Rainfall Monthly Averages Figure 4e Year 5 Daily Rainfall Monthly Averages Figure 4f Year 6 Daily Rainfall Monthly Averages Figure 4g Year 7 Daily Rainfall Monthly Averages Figure 4h Years 9/01-8/07 Daily Rainfall Monthly Averages Figure 5 Storm Event Hydrologic Parameters, Year 1 through Year 7 Figure 6 Mercury in Major Outfall Trunk or Lateral Line Figure 7 PAH Concentrations in Major Outfall Trunk or Lateral Line Figure 8 DEHP in Major Outfall Trunk or Lateral Line Figure 9 Total PCBs in Major Outfall Trunk or Lateral Line Figure 10 NWTPH in Major Outfall Trunk or Lateral Line Figure 11 Regression Analysis of Significant Time Trends

4 Tables Table 1 Mean Low-Low Water (MLLW) Tidal Elevations Table 2 Description of Whole-Water Sample Locations Table 3 Description of In-Line Sediment Trap Sample Locations Table 4 Rainfall for Years 1-7 Sampling Table 5 Seasonal Rainfall Totals for Years 1-7 Table 6 Volume Sampled and Flowrates for Baseflows - Years 1-7 Table 7 Portion of Storm Event Sampled in Tidally Influenced Drains Table 8 Ranges of Magnitude and Intensity of Years 1 to 7 Stormwater Runoff Hydrographs Table 9 Number of Storms for Each Amount of Precipitation Table 10 Precipitation Summary of Storm Events Sampled Table 11 Number of Samples Collected By Season for Years 1-7 Table 12 Rainfall for the Stormwater SPM Sampling Periods Table 13 Estimated Runoff Volumes for Stormwater SPM Sampling Period Table 14 Summary of Years 1 through 7 Statistics for Baseflow Table 15 Summary of Years 1 through 7 Statistics for Stormwater Table 16 Results of ANOVA Pair-Comparison Tests: Baseflow and Stormwater Table 17 Lognormal Goodness-of-fit Test Table 18 Percent Coefficient of Variation for Stormwater Constituents Table 19 Estimated Sample Sizes and Monitoring Durations for Trend Analysis Table 20 Results of Seasonal Kendall Time Trend Analysis Table 21 Results of ANOVA Pair-Comparison Tests Sediment Trap Particulate Data Appendices Appendix A Whole Water and Stormwater Suspended Particulate Matter (Sediment Trap/Sump) Monitoring Locations Appendix B QA/QC Case Narratives for Year 7 Baseflow, Stormwater and Stormwater Suspended Particulate Matter (Sediment Trap/Sump) Samples Appendix C Field Report Summary for Year 7 Baseflow, Stormwater and Stormwater Suspended Particulate Matter (Sediment Trap/Sump) Samples Appendix D Year 7 Field and Hydrological Data for Each Sampling Event Baseflow and Stormwater Appendix E Analytical Data for Baseflow, Stormwater, and Stormwater Suspended Particulate Matter (Sediment Trap/Sump) Appendix F Statistical Summary for Baseflow and Stormwater Data Appendix G Box and Whisker Plots for Stormwater and Baseflow Data Appendix H Annual Variations of Stormwater and Baseflow Data Appendix I Seasonal Variations of Stormwater and Baseflow Data Appendix J Box and Whisker Plots for Stormwater Data Years 1 through 7 Appendix K Data Validation Report - Stormwater Monitoring, August

5

6 1.0 INTRODUCTION Under a Unilateral Administrative Order dated September 30, 2002, and a Consent Decree with the Environmental Protection Agency (EPA) dated May 9, 2003, the City of Tacoma is implementing a stormwater monitoring and source control program for the storm drains entering the. The City s program is called the Thea Foss Post-Remediation Source Control Strategy. The purpose of the monitoring program component is to evaluate the quality of stormwater discharges to the Thea Foss Waterway and the effect of those discharges on sediment quality. The results of these efforts are being used in an ongoing evaluation of source loadings to the waterway to help identify and manage new or existing sources and to protect sediment quality in the years following the sediment remedial action. Constituents of concern (COCs) are those chemical constituents which have modern ongoing sources and which pose the greatest risk to sediment quality, and are therefore the primary target for source control activities for the storm drains as well as for other potential sources. Bis(2ethyl-hexyl)phthalate and various Polyaromatic Hydrocarbons (PAHs) are the primary COCs for the waterways and have therefore been the focus of source control activities to date. Phthalates are used in plastics, rubber, detergents, lubricants, and many other products. Bis(2-ethylhexyl)phthalate is typically found more frequently and at higher concentrations than other phthalate family compounds. It is also commonly know as di(ethylhexyl)phthtalate and will be referred to as DEHP herein. PAHs are found in combusted hydrocarbons such as car exhaust, oil pan drippings, other combustion engines and historical sources from old tanks or industrial activities. This list of contaminants of concern is being used to focus ongoing source control efforts. Annual stormwater and stormwater suspended particulate matter (SPM) monitoring of the stormwater discharges to the Thea Foss Waterway are being used to evaluate effectiveness of these source control efforts and to provide early warning of new problems. The monitoring efforts, their results and evaluation, were outlined in the Sampling and Analysis Plan (2001 SAP) for Thea Foss and Wheeler-Osgood Waterways dated September 2001 (Tacoma 2001) approved by EPA September 13, BACKGROUND Historically, the Thea Foss outfalls have been sampled since Stormwater and baseflow sampling of the Thea Foss outfalls was completed from 1986 through Stormwater SPM (sediment trap) sampling of the Thea Foss outfalls and upstream sites was completed from 1996 through The first stormwater sampling of the Thea Foss outfalls under an EPA Administrative Order of Consent occurred in Reporting limits for several undetected constituents in the stormwater were not low enough at that time, which limited the ability to complete the recontamination assessment and fully define the list of COCs for the storm drain source control program. 1