​Tier II Review: Nontidal Wetlands and Waterway Construction

​This online resource provides an overview of the general Tier II review process for the Nontidal Wetlands and Waterway Construction Divisions.   Keep in mind that when using this webpage, the permitting authority will use application and site specific information to ultimately determine final permit conditions and requirements.
The purpose of the Tier II review is to prevent degradation to high quality waters due to permitted activities.  To protect downstream resources, the Tier II review is implemented at the watershed scale.  This means that permitted activities occurring anywhere upstream of the designated stream segment may be subject to review.  Ample watershed forest cover, sufficient riparian buffers, and lower levels of impervious cover are essential to maintaining high quality waters. Therefore, avoiding, minimizing, and mitigating the environmental impacts associated with permitted activities is necessary to protect Tier II waters.   

General Nontidal Wetlands and Waterway Construction Tier II Review Workflow:



In addition to  the Nontidal Wetlands and the Waterway Construction Divisions application reviews, MDE coordinates with a variety of partners such as other State agencies, county and local government, non-profit and non-government organizations to develop and incorporate policies and other best management practices into broader watershed initiatives.  This effort includes a strong focus on developing tools that prioritize practices leading to stronger Tier II waters protection, while maximizing the co-beneficial use of existing policies and programs, such as the Forest Conservation Act.
Click here for more information regarding assimilative capacity.  Click here to view the interactive Tier II webmap where users can see the locations of Tier II stream segments and catchments, and receive more information about assimilative capacity status.​
Simple Accordion

Overview of Tier II Review

  • Common Situations that Generally Do Not Require Tier II Review

These situations are generally temporary in nature, consist of essential maintenance activities, and are not expected to have a substantial negative impact on water quality. Such situations include:

  • General Waterway Construction Permits
  • Road resurfacing (maintain existing roadway footprint)
  • Emergency work where human safety is of immediate concern (e.g. bridge collapse, etc.)
  • Habitat restoration, rehabilitation, and stabilization activities
  • Environmental Impact Avoidance Alternatives​

Applicants should consider design alternatives that avoid or limit environmental impacts to Tier II waters. This may include:

  • Alternate facility or structure locations,
  • Alternate routes for roads or pipelines, and
  • Alternate stream crossing methods.
  • Common Environmental Impact Minimization Alternatives

Applicants should incorporate controls that will minimize unavoidable impacts to key resources that support high quality waters. This means giving special attention to maintaining sufficient stream buffers, and avoiding both cumulative decreases in forest cover, and increases in impervious cover, like parking lots.

Enhanced Best Management Practices for Tier II Waters

To help streamline the review process, MDE provides a primary checklist of core enhanced best management practices (BMPs). This list includes a flexible range of preventative, proactive, and responsive practices to minimize unavoidable impacts.

The form also captures information about riparian buffers, and forest and impervious cover changes proposed in the permit application, which can be used to aid in mitigation, or project justification.

pH Management

Contact between in-stream water and fresh grout material can lead to extreme fluctuations in pH which may have an immediate adverse effect on water quality with the potential to cause fish kills. MDE provides guidance and resources to help applicants choose appropriate best management practices to address pH issues that may arise during permitted activities such as pouring cement during a culvert repair.

  • Environmental Impact Mitigation Alternatives

Land use conversion, especially from forest to impervious surfaces, and increases in impervious cover (ex. parking lots), contribute to, or directly cause cumulative water quality degradation. Under certain circumstances, when a project results in the net reduction of forest cover and/or the net increase impervious cover within the Tier II watershed, mitigation is an option to help offset unavoidable impacts. The preferred mitigation method is ‘in-kind’. This means that the amount of forest restored within the Tier II watershed should equal the amount of forest lost due to the permitted activity. This also holds true if an area is permanently converted to impervious cover, but is not managed with environmental site design (ESD). Environmental site design helps to mimic natural run-off characteristics and address impacts associated with development.

In many cases fulfilling the ESD stormwater management requirements, along with strategic planning during the process of developing forest conservation and mitigation plans help to meet the requirements of a Tier II review.

  • Tier II Social and Economic Justification

If impacts cannot be fully avoided, minimized, or mitigated, the applicant may have to provide MDE with a social and economic justification (SEJ). The SEJ must demonstrate that an economic hardship and/or public benefit overrides the value of the ecological services or water quality benefit that the Tier II water segment provides. The applicant must also provide documentation to show that all reasonable avoidance, minimization, and mitigation alternatives have been considered, and where economically feasible, implemented.

  • Other potential requirements

At times, permits for certain large and complex Tier II Reviews may contain special conditions like water quality monitoring. For example, special Tier II permit conditions would apply to a permit for a new, large underground pipeline. Special permit conditions could include monitoring for basic water chemistry parameters like temperature or pH, or it may be more involved, requiring biological monitoring. MDE biological monitoring guidelines can be found here.

Other Nontidal Wetlands and Waterway Construction Divisions Tier II Review Resources:

• pH form
Click here to return to the Maryland Tier II Waters homepage.
Please direct any questions or comments concerning Maryland's Antidegradation program to Angel Valdez at Angel.Valdez@maryland.gov or 410-537-3606.
This page was last updated 05/2018.