Frequently Asked Questions About Natural Diversity Data Base Reviews

Is there a fee for the Natural Diversity Data Base (NDDB) review?

Where can I find the most recent NDDB maps?
PDF maps by town can be found on the NDDB Maps webpage. Interactive map viewers can be found at Connecticut Environmental Conditions Online . GIS data can be downloaded from the DEEP GIS Open Data website. If you do not have access to a computer, maps can be viewed using computers available in the DEEP Public File Room at 79 Elm Street in Hartford. However, it is recommended you schedule an appointment online ahead of time to confirm your spot on any given day. Visit the Environmental Quality Records Center (File Room) webpage to schedule an appointment and also learn about the DEEP document online search portal.

How do I know the date of the map?
The date of the map is printed in the title block on the 8.5" x 11" maps and in the explanation section of the larger format maps. In the GIS data, refer to the field for the map date.

Can the NDDB review process and response letter be utilized to stop a development or other project type?
Generally speaking, no. The NDDB determination letter is used to demonstrate compliance with CT’s Endangered and Threatened Species Act as part of the state permit application process or when state moneys are utilized in project funding. Many development and other projects are approved at the municipal level and local concerns should be brought to municipal officials.

If my project is close to an NDDB area, but not really touching it, do I have to submit a review?
If your project does not meet pre-screening as stated in the instructions, you do not need to submit an NDDB review. Be sure to consult any related permit application instructions and follow the requirements for the relevant permits. If you are close to but just outside of an NDDB shaded area, you may still want to submit a request. If the preferred habitat for a species is documented nearby and the habitat occurs on your project site, the species may also occur there. Obtaining information early in your planning process and addressing endangered species issues up front can work to your advantage. Ignoring the issue increases the chance that others concerned about the project’s impact will raise questions at a later phase when changing plans can be more costly. Being outside of an NDDB area means that there are no known reported observations of state-listed species on your site; however, they could be discovered during an on-site survey. Consultation with the NDDB should not be substituted for on-site surveys important for a thorough environmental review.

Is the NDDB a comprehensive assessment of state-listed species?
No. The NDDB data are a compilation (or collection) of observations from contributors and are not the result of comprehensive statewide field investigations. Historical and low accuracy town and county level observations have been omitted from the maps. Consultation with the NDDB should not be substituted for on-site surveys required for thorough environmental assessments.

How long does an NDDB review take?
Review time is highly variable and depends on the size and complexity of the project. A standard biologist review typically takes 8-10 weeks. However, the timeline could be expanded for 6-12 months if additional survey work is needed, especially if it is necessary to wait for the next field season to collect data or there are multiple listed species present. The applicant may be required to produce additional documentation, such as biological surveys, which must be completed prior to submitting any state permit applications. We recommend that you start this process early and well in advance of any deadlines. The timeline also depends on the completeness of application materials. You will need an NDDB determination letter that has not expired to include with any DEEP permit applications.

Can I submit my DEEP permit application while I am waiting for my NDDB response?
No. If you are in an NDDB area, you must submit a NDDB determination that has not expired with your permit application, or your application will be deemed insufficient and you risk losing your application fee.

I used to be able to request a Preliminary Site Assessment. Is that option no longer available?
Preliminary Site Assessments are no longer being provided through the paper application. If you would like a Site Assessment, you must utilize the DEEP’s ezFile Portal. Once you create an account, you may submit a Site Assessment request. (FAQs for Submission Through ezFile Portal)

What is a site assessment and what can I do with it?
Site assessments are offered as a way to get a general species list for a property and are only available through the DEEP ezFile Portal. The species list can be used with a habitat evaluation for initial planning. Site assessments are not an NDDB determination and cannot be used to fulfill the requirements of a DEEP permit application. You may wish to request a Site Assessment to help guide survey work prior to submitting an NDDB Review Request for a project; however, please be aware that during the NDDB Review process, program biologists may have concerns for additional species not provided with the original Site Assessment.

Will I be required to conduct field surveys for all species listed in the site assessment letter?
Not necessarily. If you submit for a NDDB Review Request after receiving a Site Assessment report, the response will be based on project details provided in your application. If the reviewing biologist determines that additional information is needed, details will be indicated in a follow-up letter. Read your letter carefully (*see sample below). In some cases, a habitat evaluation may be sufficient, or you may need a qualified biologist to conduct specific biological field surveys. Ideally, field surveys are recommended in order to evaluate potential habitat and species presence, and use of the site. Highly-developed sites with little suitable habitat or projects with minimal or temporary impacts may not need surveys. You may be able to minimize disturbance or pollution; develop avoidance, preservation, or mitigation measures; or design habitat buffers or improvements based on your knowledge of the site conditions alone.

Why am I being asked to survey for species that were not returned in a site assessment?
When a biologist reviews an application and more detailed site information, they may determine surveys are needed and that suitable habitat exists for multiple species that were not included in a site assessment. The site assessment data do not include entire species ranges nor do the data include all suitable habitat; expert review may result in additional species deemed appropriate.

How do I find a qualified biologist?
DEEP does not keep a list of qualified biologists. You may consult with local universities or botanical and zoological organizations who may be able to recommend knowledgeable persons. You should ask for references and examples of experience with species found in Connecticut or New England. Any activity that involves the capture, handling, marking, or salvage of wildlife will require the biologist to obtain a DEEP Scientific Collector’s Permit authorizing them to perform the work proposed at your site. Activity involving the collection of any plants (regardless of whether or not state-listed) on state-owned land or from waters of the state will require the biologist to obtain a DEEP Scientific Collector’s Permit authorizing them to perform the work proposed at your site. Activity involving the collection of State-listed Endangered or Threatened plants on or from private land, public land, or waters of the state, will require the collector to obtain written permission from the landowner. 

*Understanding Survey Requirements

Sample Language (This is an example only. Language provided may differ slightly depending on the individual review.)

According to our records, there are known extant (existing) populations of state-listed species that occur within or close to the boundaries of this property. Attached is a list of species known from this area. Please be advised that this is a preliminary review and not a final determination. A more detailed review will be necessary to move forward with any environmental permit applications submitted to DEEP for the proposed project. This preliminary assessment letter cannot be used or submitted with permit applications at DEEP. This letter is valid for one year.

To prevent impacts to state-listed species, field surveys of the site should be performed by a qualified biologist with the appropriate scientific collecting permits at a time when these target species are identifiable. A report summarizing the results of such surveys should include:

  1. Survey date(s) and duration.
  2. Site descriptions and photographs.
  3. List of vascular plant and animal species within the survey area. Please use scientific names rather than common names.
  4. Photographs of any state-listed plant species showing appropriate features and of sufficient quality to confirm identification.
  5. Data regarding population numbers and/or area occupied by state-listed species.
  6. Discussion of diagnostic identifying features of plant species targeted and/or found during surveys.
  7. Detailed maps of the area surveyed, including the survey route and locations of state-listed species.
  8. Statement/resume indicating the biologist’s qualifications.
Responding to a Survey Requirement

The site surveys report should be sent to the reviewing biologist and the CT DEEP NDDB Program ( for further review.

Incomplete reports may not be accepted. 

NDDB information includes all information regarding critical biological resources available to us at the time of the request. This information is data collected over the years by the DEEP’s Natural History Survey, other DEEP scientists, landowners, private conservation groups, and the scientific community. This information is not necessarily the result of comprehensive or site-specific field investigations. Consultations with the NDDB should not be substitutes for onsite surveys necessary for a thorough environmental impact assessment. The result of this review does not eliminate the possibility that listed species may be encountered on site and that additional action may be necessary to remain in compliance with certain state permits.


FAQs for Submission Through the ezFile Portal

Can I email my review request form, map, and supporting documents instead of using the ezFile portal?
At this time, submitting your application through the ezFile portal is the most efficient way to process your review request. Assistance is available if needed.

I cannot move to the next section in the application or the section header has turned red, how do I move forward?
If a section header turns red, then you have not completed the required information. Review each question and make sure you have responded, and no errors are displayed. If you cannot complete a section, make note of your filing number. You can "Save as Draft" or "Save and Exit" and return to complete the filing at another time. If you need to go back and change a previous section, you may do so, but you may lose data entered in subsequent sections. Each section builds on previous questions and, if the logic changes, you will be forced to start again. When a section turns green, the information is complete, and you can select the next header to move to the next section. In the Requester Information, select on "Next" in order to move to the Preliminary Screening section.

Why do I receive an error during address verification?
If the address verification includes the 5-digit zip followed by a dash but does not include the +4, you will receive an error and may get stuck at the Site information section. You must remove the dash or choose to not accept the address with the dash.

The Site information times out when I try to Save and Continue from the map, will I lose my information?
It is recommended that you "Save as Draft" before moving to "Draw or Upload". After you draw or upload and label your project polygons, upon selecting “Save and Continue”, several processes happen that can take time. The system will export a map and shapes that are saved to the filing. Be patient. You may get a message asking you to wait -- try to wait for the process to complete. If you get sent back to the home page, the filing will be in your open filings, and you can use the pencil to reopen and continue with the application. Keep track of your filing number so you can easily relocate the correct application.

Where will my approval letter be sent?
Your approval letter will be sent to the email address of the user who has entered the filing into the portal system. Note that even though the user may enter a client in the Requester Information, who has a different address, the email address that is stored in the user’s portal account is the only one that will receive letters automatically. This information can be viewed and updated in the Account Manager.

How do I renew my NDDB Determination from my portal filings?
It is important to keep track of your filing numbers. In My Home/Filings, find the filing in your online portal under Finalized Filings. Under Info, select the fourth icon, the circle arrows, and follow the prompts to renew with no modifications or to copy forward if there are modifications needed.

If you cannot find your filing, or if your original determination was not entered in the portal, you can always submit a new request. For a renewal of a determination that was not entered in the portal, you can make note in the project description that this is a renewal of a previous determination, and include the previous determination number, and if applicable the reason for the renewal.

How do I know which project category, type, and sub-type to select?
Follow the drop-down list choices and pick the one that best describes your project. If in doubt, choose a project type that seems to overestimate the amount of impacts, or see below for guidance on submitting multiple project activities. You may wish to do a site assessment before conducting your full environmental review. This will provide a preliminary species list for which you can plan your protection plans. Providing and incorporating protection measures in your project design may speed up consultation once you submit for your project review. 

My project includes multiple activities, how do I choose a project type?
Each automated response letter will address only one project activity type. If your project activities are multipart, you may need to submit your request separately for each of the project types. For example, if you are conducting a timber harvest with invasive species control, you will need to submit separately for the timber harvest and the terrestrial invasive species control. If the preliminary result from your first submission is Biologist Review, you will only need to submit once; and when answering the project questions, you should describe all of the activities taking place. If your first submission results in an automated response, then you need to resubmit for any additional activities. You can copy some elements of the application from your Finalized Filings. Go to Finalized Filings and under Info, select the fourth icon, the circle arrows, to “renew filing”, and follow the prompts to copy forward portions of the request. In order to change the project type, do not copy the project information.

I cannot enter coordinates on the mapping screen, how do I find my site?
Yes, you are correct. You cannot use coordinates to find your site. In the search box, enter the nearest street address or a major feature/lake, etc., to get to the general location to map your project site.

My project has multiple locations, can I draw multiple locations for one application?
Each application should be for one project type at a single site; however, multiple areas within a reasonable distance can be added. For example, you can draw your construction footprint and stormwater discharge location as two polygons in the same application. Polygons that are too far apart may make it difficult to interpret your results. You can either upload a zipped shapefile, or draw multiple polygons. For each polygon, you will be required to fill out all the attributes in order to continue. If you draw multiple polygons, a pop-up alert will appear stating that one or more of your polygons is missing one or more required attributes. Select "okay" and you will be prompted to fill in those attributes.

Upload instructions: Prior to uploading, create a polygon shapefile of your project area, including the area of work and any access, staging, or discharge areas. Zip all components of a single polygon shapefile and use the upload tool to navigate to your saved zipped file. After uploading, you will need to click on each individual polygon in the map and add labels before you can continue.

I am stuck in the map section and cannot continue, how do I exit?
If you cannot complete the map section and wish to leave the filing, you can Save as Draft and will get a message that you can exit to the Home Screen. The Site section will be incomplete, but it should save the rest of the application. When you wish to return and finish the filing, find the filing in Open Filings and use the pencil to edit the filing. The Site Information will likely be highlighted in red, you can return and finish that section in order to move on.

I have moved past the Preliminary Results section of the application and now the Site Information section has reverted from green/complete to gray/incomplete and I cannot finish the application.
Return to the Site Information section and select ‘Save and Continue’ to reprocess the saved polygon. You will then be able to continue with your application submission.

I need to upload documents. What file types are acceptable?
We prefer uploaded documents to be in PDF form. The maximum file size is 20mb, but overly large files can cause system performance issues. Please optimize documents with large drawings and photos prior to submission.

How can I be sure that my application was submitted?
Please check the filing status to confirm submission. Your ezFile home page has two sections; one for Open Filings and one for Finalized Filings. Applications that have been successfully submitted will be listed in Open Filings with a status of Submitted (for biologist review determinations) or listed in Finalized Filings with a status of Issued (for e-generated determinations). If your status is Started, then it has not been successfully completed and submitted. Use the pencil to Edit the filing and make sure all sections display green with a check mark. Revisit any gray or red sections and complete the required information. If you go back and make changes to a previous section, all subsequent sections will be erased and will need to be completed again.

I asked NDDB to withdraw my application for review and it is now back in my portal Open Filings. Can I edit this filing and submit again?
NO - the system does not allow you to edit or resubmit a withdrawn filing. You must create a new filing. If you need to retrieve your original uploaded documents, you may access them using the paper clip icon on the withdrawn filing. Once accessed, save them to a local drive and upload them with your new application.

I did an NDDB Site Assessment, but I do not see it in My Filings.
Site Assessments are not saved as Filings. You must download and save the resulting report when it is generated.

I received a “sensitive species” in my preliminary results. What species is this?
Some highly collectible and sensitive species names have been withheld.

My site is in an NDDB area on the maps, but I received a “no species” letter from my portal filing, is this right?
The pre-screening maps and the data intersected in the portal automated decisions are not the same and were generated using different processes. It is possible to be in an NDDB area on the maps, but receive a “no species” result. Part of the screening map model includes a random shift so that species observations are not in the center of the NDDB area. You can perform a site assessment and draw a broader area to see what species may be in the area. If you are concerned that we missed something, you can send an email to

My site is not in an NDDB area on the screening maps, but I received species recommendations or biologist review for my filing. Is this right?
The pre-screening maps and the data intersected in the portal automated decisions are not the same and were generated using different processes. The screening maps are more confined around observations and the automated data may include additional habitat areas that have been modeled and interpreted as potentially suitable.

I received a Request Additional Information response letter from my reviewing biologist. How do I submit the requested information?
You must email your information to the reviewing biologist, as noted in the response letter. The NDDB ezFile system does not have the capability to upload additional documents to your filing after it has been submitted.

If I leave my portal session idle for a few minutes, I get an error when trying to enter information.
ezFile has automatically logged you out of your session and you need to log back in. You should always Save As Draft if you will be away from your session for a few minutes.

The portal is kicking me out or I am having other technical difficulties.
Send an email to Include a screen capture of any error messages and a description of what steps you were taking when the error occurred.

Content last updated in January 2024.