What is the DDCT and why is it needed
- What is the DDCT?
- The Density and Disturbance Calculation Tool, or DDCT, is a spatially based tool that calculates both the number of disruptive activities averaged per square mile (640 acres) and total surface disturbance within the DDCT assessment area. The assessment area is created based on buffers around proposed projects in protected sage-grouse core areas, and subsequent buffers around any occupied, core area leks within the first buffer. Limits for disruptive activities and disturbances, along with buffer distances are laid out in the Governor’s Executive Order 2011-5.
For additional information please refer to the following documents:
Executive Order 2011-5 - Greater Sage-Grouse Core Area Protection
Sage-Grouse Habitat Management Policy on Public Lands
Sage Grouse Executive Order Check Off List
- Why is the DDCT needed?
- With the signing of the Governor’s Executive Order 2011-5 it became necessary for state of federally permitted development within a Sage-Grouse Core Areas to comply with the SGEO requirements. The DDCT provides information on the density and disturbance thresholds related to the SGEO requirements.
- What is a surface disturbance?
- Any anthropogenic or wildfire surface disturbance that results in loss of sage-grouse habitat is considered disturbed in the DDCT calculation. Surface disturbance includes, but is not limited to, roads, well pads, mining operations, cropland, buildings, some vegetation treatments, wind turbines, and pipelines. Some linear features are considered exempt from DDCT calculations; please see the “Disturbance Calculation Process for Linear Features” for additional information.
- How are surface disturbances mapped?
- Some surface disturbances come from other spatial datasets; however, these spatial datasets are not complete for all disturbances in the state. For mapping disturbances in the DDCT assessment area, a method called head’s up digitizing needs to be used to ensure all disturbances are mapped. When performing head’s up digitizing make sure to use a minimum 1:5000 scale and the 2009 NAIP aerial photography images and be sure to digitize around the outside perimeter of the disturbance. Visual examples of disturbances are provided below:
Ranch, road, and building
Road and cropland
Road and pipeline/utility corridor scar
Well pad and road
Ranch and assorted disturbance
Pipeline and watering hole
Pipeline, road, and electrical infrastructure
- What information about surface disturbances is needed
- Information needed for surface disturbances to be handled correctly within the web application includes defining whether it is a disruption, a disturbance only, or exempt. Disturbance and Disruption are the two fields used to determine how the web application counts the disturbances. Below is a table with example of valid combinations:
||Disruption (1/640 count and contribute to percent disturbed)
||Oil and Gas infrastructure with human presence excluding access road, pipelines, and power lines, or active mining operations.
||Disturbance (only used in percent disturbed)
||All other anthropogenic disturbance
||Areas determined to be “de minimus” or disturbed but meeting the suitable habitat definition or pre-1994 conditions in Northeast Wyoming
Other useful information recorded with the disturbance is the type of disturbance it is. Values for the disturbance types can be found in the “Where can I find the values to put in the “Type” and “Category” Fields?” question below. The surface disturbance types are grouped into categories, which is the first number of the disturbance type number
- How are surface disturbances uploaded?
- Uploading surface disturbances, either proposed or existing, is possible in the web application if the features are contained in esri© Shapefile format.
- What information is needed in the esri© Shapefile?
- The esri© Shapefile must contains polygons of disturbances and a valid spatial reference. Other information contained in the esri© Shapefile can be used in the application if the data are available. Below is an example of how to code the disturbances and disruptions during the upload process
||1 is yes, 0 is no
||1 is yes, 0 is no
||First number of the type code
||Code for type of disturbance
||Values can be found below
- Can I download a blank disturbance shapefile?
- A blank disturbance shapefile is available by downloading this file
- Where can I find the values to put in the “Type” and “Category” Fields?
- The “Category” and “Type” are derived from the same table. The type is the whole two digit number, while the category is the first digit of the number. For example, a well pad would have a type of 48 and a category of 4. Below is the complete table:
|0 - Unknown
||4 - Oil and Gas
||Unknown Type of Disturbance
||General Oil/Gas Disturbance (type unknown or varied)
|1 - Road / Transportation
||Abandoned Well Pad (oil/gas)
||Other Improved Road
||Test Well (oil/gas)
||Dirt Road (BLM, County)
||Blowout Mud Pit (oil/gas)
||Oil/Gas Access Road
||Well Pad (general)
||Mining Access Road
||5 - Mining
||General Mining Disturbance (type unknown or varied)
||Right of Ways
||Blowout Mud Pit (mining)
|2 - Structure / Development
||General Structure (type unknown or varied)
||Mining structure (type unknown or varied)
||Mining Reclamation (Large Scale)
||General fence (type unknown)
||Gravel Pit/Gravel Storage
||Private Residential Development (general)
||6 - Utilities
||General Electrical Disturbance (type unknown)
||Residential Area / City Boundaries
||Power supply center
|3 - Range Land
||General Range Disturbance (type unknown or varied)
||Water Source General (type unknown)
||7 - General Linear Disturbance
||General Linear Disturbance (type unknown)
||8 - Fire and Vegetation Treatments
||Man Made Wetland
||Unknown Vegetation Treatment
Disturbance Calculation Process for Linear Features
The impacts of linear disturbances are varied. The following are suggestions for dealing with linear features:
- Roads will contribute towards disturbance calculations, with the exception of two-track road less than 10 feet wide for a majority of the length. The actual footprint should be digitized.
- Transmission LinesSGIT
- Overhead transmission corridors established in Executive Order 2011-5 (1/2 mile either side of existing 115kV or larger lines and the east-west corridors mapped in Attachment D will not count toward disturbance calculations for any new projects located outside the corridors. In essence, Executive Order 2011-5-established corridors are considered unsuitable habitat for the purpose of DDCT calculations and will not be counted in the numerator (disturbance) or denominator (total DDCT acreage).
The goal of Executive Order 2011-5 is to avoid further fragmenting areas with distribution and transmission lines of all sizes.
Distribution and transmission lines are permitted inside SGEO designated corridors (Pages 4, 15, & 16). The same distribution and transmission lines are not permitted outside of corridors unless there is demonstration of no declines in sage-grouse populations (Pages 4 & 17).
Currently, it is unknown what type of lines impact sage-grouse populations, and to what extent. There will be new distribution and transmission lines that will need to be built to service existing approved projects.
If the need for future distribution and transmission lines is likely, new projects that require a DDCT for approval should include distribution and transmission lines in their DDCT as part of the proposed disturbance. If it is absolutely necessary to site new distribution and transmission lines through a core area outside of an existing corridor and lines cannot be buried, lines should be sited to minimize any potential impact on sage grouse or their habitats, and preferentially consider siting along or adjacent to existing long-term linear disturbance features whenever possible (i.e., along existing occupied above ground utilities, roads).
Lines permitted but not located in an Executive Order 2011-5 transmission corridor (described above) will be counted towards the 5% disturbance calculation. Line disturbance is equal to right-of-way (ROW) Width x Length and includes all access roads, staging areas, and other surface disturbance associated with construction outside of the ROW.
All new transmission and distribution towers/structures should be designed to include raptor proofing/perch deterrent
- Any new pipelines constructed in utility corridors established by and as defined in BLM Resource Management Plans (RMP) including those portions of the corridors located on non-Federal lands in core population areas, that have been disturbed by a previous utility installation, are exempt from conducting a DDCT analysis and will not be included in disturbance calculations for any new projects located outside these corridors. In essence BLM RMP established corridors occupied by utility infrastructure are considered unsuitable habitat for the purpose of DDCT calculations and will not be counted in the numerator or denominator. New pipelines outside BLM RMP corridors, but in core population areas, would contribute towards the 5% surface disturbance calculation until the area is reclaimed to suitable sage grouse habitat.
- Units located within a new project DDCT
- When dealing with situations where the DDCT encounters a Federal Unit established prior to 8.1.2008, the BLM field manager will need to work collaboratively with both the unit holders and the project proponents to determine if the existing unit boundary accurately reflects the actual disturbance likely to occur within the unit under a full development scenario. It is imperative that each of these situations is addressed with flexibility and on the ground knowledge of the landscape and habitat within the DDCT Assessment Area:
- New Development inside Units: The key to planning development in units within core areas is to create the least amount of disturbance to suitable habitat. A unit is not automatically considered an approved activity; however, there is an expectation that development of the unit will occur. Each situation will need to be handled case-by-case and information such as development plans and reservoir characteristics will play into the BLM’s decision on how to manage density and disturbance. In many cases this will best be accomplished by concentrating activity within existing (prior to 8.1.2008) unit boundaries. Disturbance and density calculations may exceed the thresholds for a DDCT because development is being concentrated in a pre 8.1.2008 unit.
- New Development outside Units: Within existing, (pre- 8.1.2008) recognized federal oil and gas units and other recognized developments (per Executive Order 2011-5 page 2), coordination will be a key element for the BLM, the existing unit holder, and any new project proponent inside or outside the unit. A unit will be considered 100% disturbed based on the current unit boundary and will be counted as 1 disruption unless a plan of development showing long-term development is available for consideration. A unit will often have an approved plan of development that contemplates a shorter time than the life of the project, so available information may only show a portion of the entire development. In the event that a unit within the DDCT assessment area, but outside the project area, causes the project to exceed the disturbance/disruption thresholds when the unit is considered 100% disturbed and 1 disruption per 640 acres, the BLM Field Manager must work with the unit operator to determine actual development plans or the proposed project will violate the Executive Order.
Features that do not contribute to the disturbance and disruption thresholds
- Exempt (“de minimus”) Activities
- Existing Land Uses and Landowner Activities in Greater Sage-Grouse Core Population Areas That Do Not Require State Agency Review for Consistency With Executive Order No. 2011-02
- Existing animal husbandry practices (including branding, docking, herding, trailing, etc).
- Existing fanning practices (excluding conversion of sagebrush/grassland to agricultural lands).
- Existing grazing operations that utilize recognized rangeland management practices (allotment management plans, NRCS grazing plans, prescribed grazing plans, etc).
- Construction of agricultural reservoirs and aquatic habitat improvements less than 10 surface acres and drilling of agriculture and residential water wells (including installation of tanks, water windmills and solar water pumps) more than 0.6 miles from the perimeter of the lek. Within 0.6 miles from leks no review is required if construction does not occur March 15 to June 30 and construction does not occur on the lek. All water tanks shall have escape ramps. Any terrestrial habitat improvements <10 acres will require compliance with the SGEOSGIT
- Agricultural and residential electrical distribution lines more than 0.6 miles from leks. Within 0.6 miles from leks no review is required if construction does not occur March 1 5 to June 30 and construction does not occur on the lek. Raptor perching deterrents shall be installed on all poles within 0.6 miles from leks.
- Pole fences. Wire fences if fitted with visibility markers where high potential for collisions has been documentedSGIT
- Irrigation (excluding the conversion of sagebrush/grassland to new irrigated lands).
- Spring development if the spring is protected with fencing and enough water remains at the site to provide mesic (wet) vegetation.
- Herbicide use within existing road, pipeline and power line rights-of-way. Herbicides application using spot treatment. Grasshopper/Mormon cricket control following Reduced Agent-Area Treatments (RAATS) protocol.
- Existing county road maintenance.
- Cultural resource pedestrian surveys.
- Emergency response.