Connecticut Department of Energy & Environmental Protection

Requests for NDDB Environmental Reviews

Requests for Natural Diversity Data Base Environmental Reviews

DEEP’s Natural Diversity Data Base (NDDB) reviews hundreds of projects each year to determine and mitigate potential impact on state-listed species.

State law prohibits activities authorized, funded, or performed by the State of Connecticut from threatening the existence of endangered or threatened species. The NDDB review process was designed to help state agencies meet this requirement. Applicants for state and local permits and grants may be required to consult with the NDDB as part of the application process.

Pre-screening maps

Applicants can use NDDB maps to help determine if there could be an impact to state- or federal-listed species in known locations. Shaded areas ("blobs") on the maps show approximate locations of species and important natural communities. Locations outside of the shaded areas are not necessarily free of listed species, as those locations may not have been surveyed.

If a project falls within a shaded area, applicants for state permits must submit a Request for Natural Diversity Data Base State-listed Species Review (a “Review Request”).

If your project will disturb or fragment 10 or more acres, it is strongly recommended that you conduct comprehensive biological surveys and habitat characterization across the entire site, regardless of whether the site is in a mapped NDDB Area or not. These surveys should evaluate the potential presence of all state-listed species that could occur within the available habitat. You may use the Site Assessment tool to understand known reported species in the area, but survey work should be comprehensive and not limited to targeting only those species returned by the tool.

Getting started with DEEP’s ezFile portal

Most NDDB requests are now filed and managed through the ezFile Portal. To get started, create a new user account using these instructions.

In ezFile, you can generate a Site Assessment for informational purposes only, or submit a Review Request in order to meet regulatory requirements.

Site assessment

Based on the area of interest you draw, the Site Assessment tool in ezFile returns a species list based on documented locations. This is a preliminary assessment and cannot be filed as part of a permit application.

  • Draw the location: To get a Site Assessment report, draw the area of interest and add the required location labels and comments. (You cannot upload a shapefile for a Site Assessment.)
  • Download the report: To save the report, download it immediately. Site Assessment reports are not saved in your ezFile account.

Because NDDB species records are updated continually, preliminary Site Assessments are subject to change. In a full project review, additional state-listed species may also be considered, depending on the habitat available. 

Start a new NDDB filing to submit a review request in ezFile

To initiate the NDDB review process, you must file a Review Request.

You are encouraged to file early in the planning stages of a project. Often, minor modifications to project design can help avoid or mitigate impacts on listed species.

For questions about NDDB’s ezFile application, send an email to deep.nddbrequest@ct.gov.

In ezFile, you will need to:

  • Select a project type: To ensure an accurate determination and relevant comments, it is important to select the right project type. If your project involves multiple project objectives or locations, it may be necessary to start more than one filing.
  • Answer questions: To enable review of your project, you will need to provide key details. The answers to some questions drive logic in the application and impact how the application is processed. Answer all questions carefully and completely.
  • Draw or upload the location: You will need to draw the project location or upload GIS data as a zipped polygon shapefile. Indicate the entire area affected, including any potential staging, runoff, discharge, and access areas. Use the Toggle Layers button for additional imagery and layers to assist in locating your area of interest.
  • Keep a record of your filing number: It is vital to make note of the filing number so you can refer to it in any follow-up inquiries or correspondence.

When you submit through ezFile, three initial outcomes are possible:

  • No known species: If no listed species information is available for the project location, the system will return an automated “no known species” response.
  • Automated letter: Depending on the project type and the species encountered, the system may return an automated determination letter with standard guidance for best management practices or avoidance measures.
  • Staff review: In more complex scenarios, where standard guidance is not available, your filing will go to NDDB staff for review. During the review process, you will receive correspondence from staff. When the review is complete, you will receive a determination letter from staff.

During the staff review process, species and habitat surveys may be required to assess risks and determine appropriate mitigation measures. Surveys can be completed by qualified biologists with documented relevant experience in survey and identification of a particular species in the local area. Please see the NDDB Frequently Asked Questions page for information on how to find a qualified biologist.

Submit a review request by email or mail

NDDB encourages all applicants to use the ezFile Portal, which enables quicker processing. If you cannot use the portal, please fill out the Request for Natural Diversity Data Base State-listed Species Review Form. The form is available in Word and PDF format. (You cannot use this form to complete a Site Assessment. Site assessments can only be generated through ezFile.)

Please read the instructions carefully. Incomplete forms or missing attachments will result in the request being rejected.

Completed forms should be:

Emailed to deep.nddbrequest@ct.gov

OR

Mailed to:

NDDB, Wildlife Division
Department of Energy and Environmental Protection
79 Elm St., 6th Floor
Hartford CT 06106-5127

Please submit only one request. Choose either to use ezFile or to send the form by email or mail. Do not submit the same request both ways. 

Frequently asked questions about the environmental review process

Content last updated in March 2026.