Water Quality Study for Effluent-Based Limits: Guana River/Matanzas River (GTM) Estuary and Deep Creek Watershed

A. BACKGROUND INFORMATION St. Johns County Utility Department is seeking an experienced, qualified firm to conduct comprehensive water quality studies to establish Level II Water Quality Effluent-Based Limits (WQBEL) Hierarchy One Numeric Nutrient Criteria effluent-based limits for three potential effluent outfalls located in the Guana River/Matanzas River (GTM) Estuary and one expanded effluent outfall located in the Deep Creek Watershed area with associated mixing zone study. All outfalls potential or existing are located in St. Johns County, Florida. The studies aims to assess any impacts of effluent discharge on water quality/watershed health and establish scientifically supported effluent limitations necessary to continue to protect aquatic ecosystems and public health. • Project One - Hastings WQBEL – Project will require Scope of Services sections 4-7, and 9-11 as identified below and as required by the approved Plan of Study for the WQBEL and Mixing Zone Study. • Potential Project Two - North Beach RO WQBEL - Project will require Scope of Services sections 1-11 as identified below. • Potential Project Three – AI Water Treatment Plant RO WQBEL - Project will require Scope of Services 1-11 as identified below. • Potential Project Four - CR214 Water Treatment Plant RO WQBEL - Project will require Scope of Services 1-11 as identified below.
The County prefers that Respondents possess the following certifications/qualifications: • Professional Wetland Scientist Certification • Water Model-Specific Training/Certifications • Prove passing proficiency of FDEP Rapid Periphyton Survey via FDEP online testing (FDEP Bioassessment Method Proficiency Registry Search Printout is sufficient (status can be current or past due) • Prove passing proficiency of FDEP Linear Vegetation Survey via FDEP online testing (FDEP Bioassessment Method Proficiency Registry Search Printout is sufficient - status can be current or past due) B. SCOPE OF SERVICES Services include the following tasks: 1. Objective Definition • Evaluate the impact of current and projected effluent discharges on receiving water quality, designated waterbody use, and the overall aquatic health of the waterbody • Assess compliance with existing watershed effluent-based limits and water quality standards. • Predict the effectiveness of different management strategies in achieving water quality goals.
2. Site Assessments: • Conduct field surveys and site assessments at the three potential outfall locations. • Identify and document existing conditions, including water quality parameters and environmental characteristics of each waterbody. • Conduct FDEP Stream Condition Index and Habitat Assessment, Linear Vegetation Survey, Rapid Periphyton Survey and Microbial source tracking.
3. Data Collection and Analysis: • Effluent Characterization: o Parameters: Analyze data on key parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), nutrients (e.g., nitrogen, phosphorus), metals, and pH. etc. • Receiving Water Body Assessment: o Baseline Data: Utilize baseline data on water flow, temperature, dissolved oxygen (DO), pH, turbidity, salinity, Chlorophyll-A, Nutrients (e.g., nitrogen, phosphorus) and other relevant parameters. o Spatial Variability: Consider spatial variability in receiving water quality to understand local impacts. • Statistical Analysis: o Data Interpretation: Apply statistical methods to analyze and interpret data trends, correlations, and spatial patterns. o Trend Analysis: Assess long-term trends in water quality parameters to understand changes over time. o R Programming for Statistical analysis and Data visualization o Mann-Kendall Trend Test. o Microbial source tracking.
4. Modeling Approaches • Develop and apply appropriate water quality models to predict the impacts of effluent discharge from each outfall on the receiving waters (Matanzas River and Deep Creek). Models can be as such below, but not limited to: o Water Quality Models: Choose appropriate models based on the study objectives (e.g., steady-state or dynamic models). ? Commonly used Water Quality Models that simulate the transport and fate of pollutants in water bodies (e.g., WASP, QUAL2E, CE-QUAL-W2). o Hydrodynamic Coupling: Choose appropriate models based on the study objective and integrate hydrodynamic models with water quality models to simulate flow patterns and mixing processes. ? Commonly used Hydrodynamic Coupling models: processes Delft3D, MIKE, EFDC, but not limited to. o Watershed Models: Integrate hydrology, land use, and water quality processes (e.g., SWAT, HSPF, SIMPLE, SWMM). o Evaluate approaches for Numeric Nutrient Criteria Development in Marine Waters.
5. Calibration and Validation: • Calibrate models using observed data to ensure accuracy in simulating water quality dynamics.
6. Scenario Analysis • Scenario Development: o Develop scenarios to assess the impacts of different factors on water quality (e.g., varying effluent discharge volumes or pollutant concentrations, climate change scenarios). o Simulation: Run simulations for each scenario using the selected models to predict water quality outcomes under different conditions.
7. Results Interpretation: • Analyze and interpret model results to understand how different scenarios affect water quality parameters of interest (e.g., dissolved oxygen levels, nutrient concentrations). • Calibration and Validation: o Calibrate models using observed data to ensure accuracy in simulating water quality dynamics.
8. Approval of Plan of Study: • Obtain approval for the Plan of Study from the Florida Department of Environmental Protection (DEP) to ensure compliance with regulatory requirements.
9. Regulatory Compliance • Regulatory Standards: Ensure the studies address relevant regulatory standards and guidelines for water quality and effluent discharge. • Compliance Assessment: Evaluate model results against regulatory limits to assess compliance with effluent-based limits and water quality standards.
10. Stakeholder Engagement and Communication • Stakeholder Involvement: o Consultation: Engage stakeholders, including regulatory agencies, local communities, industry representatives, and environmental groups. o Public Participation: Facilitate public participation through workshops, meetings, or online platforms to gather feedback and address concerns. • Communication of Findings: o Technical Reports: Prepare detailed technical reports outlining study methodologies, data sources, modeling approaches, and results. o Executive Summaries: Develop concise summaries for stakeholders and decision-makers highlighting key findings, implications, and recommendations.
11. Reporting and Documentation: • Prepare a detailed report summarizing the methodology, data analysis, and findings. • Provide clear and scientifically supported recommendations for effluent-based limits at each potential outfall location.