Upper Merrimack and Pemigewasset River Study Field Program 2009‐2012 DRAFT Data Report New England District – US Army Corps of Engineers September 2012 Contents Section 1 Background 1.1 Upper Merrimack and Pemigewasset River Study ............................................. 1-1 1.2 Sampling Program Overview ................................................................................. 1-2 1.2.1 Data Quality Objectives ............................................................................ 1-3 1.2.2 Study Area .................................................................................................. 1-3 1.2.3 Program Components ............................................................................... 1-6 1.2.3.1 Impoundment Studies .................................................................. 1-6 1.2.3.2 Continuous Dissolved Oxygen Monitoring .............................. 1-6 1.2.3.3 Low and High Flow Water Quality Surveys ............................. 1-7 1.2.3.4 Sediment Sampling ....................................................................... 1-8 1.3 Data Report Overview ............................................................................................. 1-8 Section 2 Impoundment Studies 2.1 Impoundment Survey 1 – June 2009 ...................................................................... 2-4 2.1.1 Event Summary ......................................................................................... 2-4 2.1.2 Precipitation and Streamflow Conditions ............................................. 2-5 2.1.3 QAPP and Field Sampling Plan Deviations .......................................... 2-7 2.2 Impoundment Survey 2 – July 2009 ....................................................................... 2-8 2.2.1 Event Summary ......................................................................................... 2-8 2.2.2 Precipitation and Streamflow Conditions ............................................. 2-9 2.2.3 QAPP and Field Sampling Plan Deviations ........................................ 2-11 2.3 Impoundment Survey 3 – August 2009 ............................................................... 2-12 2.3.1 Event Summary ....................................................................................... 2-12 2.3.2 Precipitation and Streamflow Conditions ........................................... 2-13 2.3.3 QAPP and Field Sampling Plan Deviations ........................................ 2-15 2.4 Impoundment Survey 4 – September 2009 ......................................................... 2-17 2.4.1 Event Summary ....................................................................................... 2-17 2.4.2 Precipitation and Streamflow Conditions ........................................... 2-18 2.4.3 QAPP and Field Sampling Plan Deviations ........................................ 2-20 2.5 Impoundment Survey 5 – October 2009 .............................................................. 2-21 2.5.1 Event Summary ....................................................................................... 2-21 2.5.2 Precipitation and Streamflow Conditions ........................................... 2-21 2.5.3 QAPP and Field Sampling Plan Deviations ........................................ 2-24 2.6 Impoundment Studies Data Summary ................................................................ 2-26 2.6.1 Dissolved Oxygen and Temperature Profiles ..................................... 2-26 2.6.2 Water Quality Sampling Results ........................................................... 2-26 Section 3 Continuous Monitoring 3.1 Dissolved Oxygen and Temperature Water Quality Standards ........................ 3-4 3.2 Summary of Streamflow Conditions ..................................................................... 3-4 3.3 QA/QC Procedures .................................................................................................. 3-6 i Document Code Table of Contents Upper Merrimack and Pemigewasset River Study Monitoring Report 3.4 Continuous Monitoring Results ............................................................................. 3-7 3.4.1 Impoundments .......................................................................................... 3-7 3.4.2 Downstream of Dams ............................................................................... 3-9 3.4.3 Upstream and Downstream of WWTPs ............................................... 3-10 Section 4 Low Flow and High Flow Water Quality Surveys 4.1 Low Flow Event #1 ................................................................................................... 4-5 4.1.1 Precipitation and Streamflow Conditions ............................................. 4-9 4.1.2 QAPP and Field Sampling Plan Deviations ........................................ 4-14 4.2 Low Flow Event #2 ................................................................................................ 4-18 4.2.1 Precipitation and Streamflow Conditions ........................................... 4-22 4.2.2 QAPP and Field Sampling Plan Deviations ........................................ 4-27 4.3 High Flow Event #1 ............................................................................................... 4-18 4.2.1 Precipitation and Streamflow Conditions ........................................... 4-22 4.2.2 QAPP and Field Sampling Plan Deviations ........................................ 4-27 4.4 Low Flow Data Summary and Observations ..................................................... 4-30 4.4.1 Carbonaceous Biological Oxygen Demand ................................ 4-30 4.4.2 Chlorophyll-a .................................................................................. 4-30 4.4.3 Dissolved Oxygen and Temperature ........................................... 4-31 4.4.4 Nitrogen ........................................................................................... 4-42 4.4.5 Phosphorus ...................................................................................... 4-43 4.4.6 pH ..................................................................................................... 4-46 4.4.7 Bacteria ............................................................................................. 4-46 4.5 High Flow Data Summary and Observations .................................................... 4-30 4.5.1 Carbonaceous Biological Oxygen Demand ................................ 4-30 4.5.2 Chlorophyll-a .................................................................................. 4-30 4.5.3 Dissolved Oxygen and Temperature ........................................... 4-31 4.5.4 Nitrogen ........................................................................................... 4-42 4.5.5 Phosphorus ...................................................................................... 4-43 4.5.6 pH ..................................................................................................... 4-46 4.5.7 Bacteria ............................................................................................. 4-46 Section 5 Sediment Flux Sampling 5.1 Description of Field Activities ................................................................................ 5-3 5.2 Data Summary and Observations .......................................................................... 5-3 5.2.1 Sediment Nutrient Flux ............................................................................ 5-3 5.2.2 Sediment Oxygen Demand ...................................................................... 5-6 5.2.3 Grain Size Distribution ............................................................................. 5-7 Appendices Appendix A: Sampling Station Detail Maps Appendix B: Data Plots Appendix C: Data Tables Appendix D: Data Validation and Usability Reports ii Table of Contents Table of Contents Upper Merrimack and Pemigewasset River Study Monitoring Report Appendix E: Sediment Oxygen Demand Report Appendix F: Sediment Nutrient Flux Report Appendix G: Water Quality Laboratory Reports Appendix H: Streamflow Calculations Appendix I: Field Documentation Appendix J: Other Sampling Data iii Table of Contents List of Tables and Figures Upper Merrimack and Pemigewasset River Study Monitoring Report Tables Table 1-1: Key Tributaries to the Upper Merrimack and Pemigewasset Rivers ........... 1-4 Table 1-2: Status of Program Components ......................................................................... 1-6 Table 1-3: Sampling Constituents and Field Measurements ........................................... 1-8 Table 2-1: Impoundment Survey #1 Samples .................................................................... 2-4 Table 2-2: Precipitation Totals for Impoundment Survey #1 .......................................... 2-5 Table 2-3: Missed Chlorophyll-a Hold Times for Impoundment Survey #1 ................ 2-7 Table 2-4: Impoundment Survey #2 Samples .................................................................... 2-8 Table 2-5: Precipitation Totals for Impoundment Survey #2 .......................................... 2-9 Table 2-6: Missed Chlorophyll-a Hold Times for Impoundment Survey #2 .............. 2-11 Table 2-7: Impoundment Survey #3 Samples .................................................................. 2-12 Table 2-8: Precipitation Totals for Impoundment Survey #3 ........................................ 2-13 Table 2-9: Missed Chlorophyll-a Hold Times for Impoundment Survey #3 .............. 2-16 Table 2-10: Impoundment Survey