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:
Applicants should consider design alternatives that avoid or limit environmental impacts to Tier II waters. This may include:
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.
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.
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.
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.
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.
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.
1800 Washington Boulevard, Baltimore, MD 21230