Through a competitive bidding process, the U.S. Environmental Protection Agency (EPA) Region 3 at the Chesapeake Bay Program Office (CBPO) selected Tetra Tech to provide a wide range of technical and programmatic support related to watershed planning and total maximum daily load (TMDL) development efforts for the Chesapeake Bay. Ninety-two segments of the Chesapeake Bay, which is the largest estuary in the United States, and its tidal tributaries are impaired due to a combination of nutrient and sediment impacts. To support the EPA, Tetra Tech helped address critical elements throughout the TMDL development process and fulfilled numerous tasks related to research, policy, data gathering, statistical analysis, reporting, public outreach, and information technology needs.

Our team prepared the overall TMDL report outline, wrote sections of the report, edited technical sections, completed white papers addressing key considerations, and assembled the final report. Tetra Tech also prepared the record of decision (ROD) and provided facilitation and logistical support for public outreach efforts to ensure regulatory compliance. Tetra Tech managed the public comment and response development process which required implementation of SmartC, an on-line comment management system developed in-house, to respond to more than 13,000 public comments.

To support TMDL modeling needs, Tetra Tech compiled, summarized, and formatted a number of extensive data sets for the CBPO models including agricultural census, combined sewer overflow, sewer service coverage, and non-significant point source data. We also conducted statistical analyses to determine the appropriate critical time period for TMDL modeling based on dissolved oxygen and chlorophyll-a impairments and provided database development and management as well as a summary of results through technical reports and presentations. 

Under Executive Order 13508 and the Chesapeake Bay settlement agreement between EPA and the Chesapeake Bay Foundation, EPA and the Chesapeake Bay Program were required to implement a tracking and accounting system 30 days after publishing the Bay TMDL. Tetra Tech worked with EPA and the seven bay jurisdictions to design and implement the Chesapeake Bay TMDL Tracking and Accounting System (BayTAS), a centralized data hub that provides access to data on and lends transparency to the TMDL implementation process. This system tracks point and nonpoint source implementation progress regularly between now and the compliance target date of 2025.

Since completion of the TMDL, Tetra Tech has played a lead role in supporting EPA and the jurisdictions with Watershed Implementation Plan (WIP) development, BMP tracking and verification, expert panel coordination, and modeling and application development to support enhancement of EPA’s modeling framework.

In addition, Tetra Tech implemented the first ever flow of nonpoint source BMP implementation data through the National Environmental Information Exchange Network (NEIEN). Throughout this effort Tetra Tech worked with key stakeholders and workgroups to gain consensus on the requirements for developing the data flow. Our team established a highly configurable rules engine that is constantly evolving and can be managed by CBPO staff. Tetra Tech developed separate web-based data management tools for several jurisdictions, which interface with BayTAS in support of nonpoint source BMP data exchange, standardizing the reporting mechanism for the jurisdictions ensuring that projects are appropriately represented and credited for TMDL implementation purposes.