TMDL Stormwater Implementation Resources
This webpage provides a set of technical resources for Maryland jurisdictions developing Stormwater WLA Implementation Plans. The guidance documents on this page were developed by MDE's Water and Science Administration and are recommendations only.
Maryland Department of the Environment's Water Science Administration has developed guidance which provides recommendations for many of the technical aspects of developing a Total Maximum Daily Load (TMDL) Implementation Plan. This guidance contains checklists for required elements of a permit-required SW-WLA implementation plan and makes recommendations regarding larger scale planning efforts intended to achieve overall TMDL goals.
The Maryland Department of the Environment presented a webinar on the features of the new TMDL Data Center website on June 11, 2014. This presentation gives an overview of the function and use of the resources available on the TMDL Data Center website for developing SW-WLA Implementation Plans.
Maryland's Stormwater Management Program
website provides guidance on MS4 accounting and implementing environmental site design practices.
Pollutant load reductions for MS4 accounting are used to derive MS4 credit at the state scale.
In addition, web-based nitrogen, phosphorus and sediment load estimator tools have been developed to streamline environmental planning. These tools provide estimates of nitrogen, phosphorus, and sediment load reductions with user-specified BMPs and other scenario criteria.
NEW! Maryland Forest Financing Implementation Tool (MD FFIT)
Maryland Forest Financing Implementation Tool (MD FFIT), a calculator designed to assist MD local governments, counties, and their partners seeking loans to fund forestry efforts and earn restoration credits for permits. The video shows how MD FFIT can be used to review different implementation scenarios, evaluate how much a forestry project would cost, estimate how many MS4 credits and environmental co-benefits can be achieved. The slides in the video and a user guide are also below.
Updated Nutrient and Sediment Guidance is being developed and will be published in Summer 2021.
This guidance applies to any approved Nutrient or Sediment TMDL for which a SW-WLA Implementation Plan needs to be developed under an MS4 Permit. It provides recommendations for identifying sources of nutrients and sediments, selecting management strategies for reducing nutrient/sediment loads, developing a monitoring plan, and tracking implementation progress.
NEW! TMDL Implementation Progress and Planning Tool (TIPP)
The TMDL Implementation Progress and Planning (TIPP) spreadsheet tool is meant to accompany the submission of Stormwater Wasteload Allocation (SW-WLA) Implementation Plans to MDE. It estimates load reductions at various points in the watershed planning process, allowing users to assess current progress and future BMP implementation for both local and the Chesapeake Bay TMDL. Local jurisdictions are not required to use this spreadsheet, however it is provided to simplify the county planning process. The spreadsheet uses Chesapeake Bay Phase 6 CAST-2017d Watershed Model No Action (No BMP) scenario loading rates with disaggregated Stream Bed and Bank (STB) loads at the county-8 digit and Chesapeake Bay Segment watershed scale.
This guidance applies to any approved PCB TMDL for which a SW-WLA Implementation Plan needs to be developed under an municipal separate storm sewer system (MS4) Permit. It provides recommendations for PCB source identification, source monitoring, accounting for WLA credit and consideration of alternative or adaptive approaches. A slideshow presentation on MDE's PCB guidance, as it relates to Montgomery County, is provided here.
This guidance applies to any approved Bacteria TMDL for which a SW-WLA Implementation Plan needs to be developed under an MS4 Permit. It provides recommendations for identifying sources of bacteria, selecting management strategies for reducing bacteria loads, and modeling load reductions from selected management strategies.
This guidance applies to any approved Mercury TMDL for which a SW-WLA Implementation Plan needs to be developed under an MS4 Permit. It provides recommendations for identifying sources of mercury (both local and atmospherically deposited) and creating systems to account for reductions in mercury air deposition from state and federal programs and potential reductions in local sources.
This guidance applies to any approved Trash/Debris TMDL for which a SW-WLA Implementation Plan needs to be developed under an MS4 Permit. It provides recommendations for identifying sources of trash and debris, selecting management strategies for reducing trash and debris loads, and modeling load reductions from selected management strategies.
This guidance provides additional recommendations for monitoring programs associated with Trash/Debris TMDLs. Because trash is a new and emerging pollutant in the TMDL program, limited data is available. Additional trash loading rate data will provide MDE with updated information on how trash loads may be changing over time. It can also be used by MS4 permit holders to evaluate effectiveness of selected management strategies in reducing trash.