US Department of Transportation

FHWA PlanWorks: Better Planning, Better Projects

IEFStep 4 : Assess Effects on Conservation Objectives

Integrated Ecological Framework Step

Purpose & Outcome


Identify preferred alternative conservation, restoration, and transportation investments that avoid and minimize impacts and help to implement the highest conservation and restoration priorities in the region.

  • An understanding of transportation effects and potential mitigation areas.
  • Program-level cumulative effects scenarios associated with transportation development and other future land uses.
  • Identification and quantification of mitigation needs from anticipated transportation impacts.
  • Identification of agency preferences regarding avoidance, minimization, potential conservation, and restoration investments.


TIP: To access more information on sub-steps, please visit the complete Guide to the Integrated Ecological Framework.

  1. Work collaboratively with stakeholders to weight the relative importance of resource types(including consideration of resource retention) where needed to help establish the significance of impacts and importance for mitigating action.
  2. Identify/rate how priority conservation areas and individual resources respond to different land uses and types of transportation improvements.
  3. Develop programmatic cumulative effects assessment scenarios that combine transportation plan scenarios with existing development and disturbances, other impacting features and disturbances, and existing secured conservation areas. Include climate change threats to better understand what resources/areas may no longer be viable or what new resources may become conservation priorities in the planning region during the planning horizon.
  4. Identify and quantify cumulative effects on priority areas.Intersect the REF with one or more cumulative effects assessment scenario(s) to identify which priority areas and/or resources would be affected, to identify the nature of the effect (e.g., negative, neutral, beneficial) and to quantify the effect, noting the level of precision based on the precision of the map inputs.
  5. Compare plan alternatives, and select the one that optimizes transportation objectives AND minimizes adverse environmental impacts (the least environmentally damaging practicable alternative).
  6. Identify mitigation needs for impacts that are unavoidable and that may require minimization through project design/implementation/maintenance, and that may require off-site mitigation. For impacts that do not appear practicable to mitigate in-kind, review with appropriate resource agency partners the desirability of mitigating out-of-kind (e.g., by helping secure a very high priority conservation area supporting other resource objectives).
  7. Establish the preferred transportation plan, and quantify mitigation needs including the amount and quality of area by resource type for which impacts could not be avoided and require further mitigation attention. This sub-step is a summary step, using the information developed in previous sub-steps.There is no further guidance.

Technical Questions

  • What areas have the highest degree of potential impacts? How important are these areas for resources of concern? What impacts should be avoided?
  • What areas have opportunities for mitigation, or restoration that best benefit target resources (imperiled species, watershed/aquatic resource needs)?
  • What unprotected conservation priorities can be protected through project mitigation? Should impacts be mitigated on- or off-site? Are there mitigation banks in the area or are there opportunities for bank development?
  • What rules/methods will be used for weighing tradeoffs among resource and transportation objectives?
  • How does climate change influence the selection of mitigation sites? Which species are most vulnerable?
  • For species in the planning area, what are their needs related to movement and habitat connectivity? What obstacles exist to habitat connectivity? How will species movement needs and possible transportation and land use impacts influence scenario evaluations?


  • Predicted threats associated with climate change
  • Hybrid or adjusted transportation and land use scenarios/alternatives

Case Study Examples

Click on the arrows below for detailed information on each case
  • Location: Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Wyoming

    Description: This report documents a scientific assessment of the conservation needs of the Central Shortgrass Prairie ecoregion. A type of major habitat seldom protected, it was determined that approximately 44% of the ecoregion was in need of conservation, resulting in the development of conservation goals and quantitative objectives. Data was collected from many different sources such as Natural Heritage Programs, local and state governments.

  • Location: Colorado

    Description: The Linking Colorado's Landscapes campaign brings together NGOs, State DOT and Colorado State University to identify and prioritize wildlife linkages across the State. The goal of this work is to provide transportation planners, community leaders, and conservationists with statewide data on the habitats and wildlife corridors that are vital for maintaining healthy populations of native species. Using geographic information systems (GIS) to layer spatial data of physical characteristics (e.g., topography, rivers and streams) with information about wildlife habitat preferences and movement patterns, the highest priority linkages and areas can be identified. Planners will use the analysis to identify wildlife needs within the top priority linkages.

  • Location: Colorado

    Description: The objective of this study was to develop a strategy to identify and apply natural and cultural resource metrics to a regional transportation plan, similar to an air quality conformity analysis, such that decision makers would have a meaningful tool to determine the significance of the cumulative effects of a transportation network on a given resource within the planning region. Researchers used NatureServe Vista decision support software to support the area-wide cumulative effects assessment.

  • Location: Virginia, Maryland, Washington, DC

    Description: The FHWA led the planning process for the new Woodrow Wilson Bridge that carries Interstates 95 and 494 across the Potomac River and links Maryland, Virginia, and the District of Columbia. Working with the appropriate resource agencies, mitigation measures were developed and focused not just on site-specific, but on a more regional, ecosystem based approach. Some excellent examples include the establishment of fish reefs in the Chesapeake Bay with thousands of tons of the old bridge and the installation of fish passageways on Rock Creek and Anacostia River tributaries. An independent environmental monitor and comprehensive database, tracking, and reporting system were created by FHWA to observe and report on the completion status of all agreed upon mitigation and provide up-to-date and accurate information to all involved parties. So successful were the results, that they have been since replicated on other large highway projects.


    • ../../Reference/CaseStudy/Show/19*FHWA Leads the Planning Process for Redesign of the Woodrow Wilson Bridge
  • Location: Alaska

    Description: This article describes steps taken for the creation of a "toolbox" to help assess the effects of existing and proposed roads on habitat quality and connectivity, using GIS as the main tool, in order to better inform future transportation decisions. The "toolset" is comprised of stakeholders & concerned groups, relevant literature (including local and traditional knowledge) and GIS data sets & methods useful to determining impacts & connectivity. The report identifies 150 individuals (resource managers, biologists, ecologists, GIS experts, members of the public, representatives from Native groups, federal and state agencies, and non-governmental organizations (NGOs)) concerned about the effects of roads on habitat quality and connectivity who are willing to be contacted and to collaborate in transportation planning issues in Alaska.

  • Location: , Florida, Indiana, Ohio, Minnesota, Texas, Virginia, Washington

    Description: Paper discusses how GIS can help assess and model cumulative impacts. Case studies deal with data management, interagency cooperation & outreach, spatial analysis & modeling, and re-engineering DOT business practices through the use of GIS.

  • Location: Wisconsin

    Description: Wisconsin DOT (WisDOT) discusses how during a recent update of the state's highway plan, the systems-level environmental evaluation (SEE) compared the environmental consequences of the recommended highway plan alternative to those associated with three other alternatives considered during the planning process. They compared the four plans by looking at factors such as traffic congestion, energy, air quality, land use, economic development, community impacts, sensitive land and water, total costs (to 2020), and other benefits.

  • Location: North Carolina

    Description: North Carolina's Ecosystem Enhancement Program (EEP) streamlined the project delivery process of the US 64 bypass, as well as reduced environmental impacts with avoidance and minimization and produced the most environmentally beneficial mitigation possible. EEP protects the state's natural resources through the assessment, restoration, enhancement, and preservation of ecosystem functions, and through identifying and implementing compensatory mitigation programmatically, at the watershed level. A year of multi-agency process improvement workshops determined that compensatory mitigation should be "de-coupled" from individual permits and project reviews, and performed on a watershed basis, with mitigation projects constructed in advance of permitted impacts according to collaboratively identified priorities.

  • Location: Oregon

    Description: CETAS is a multi-agency (including Federal & State transportation, natural resource, cultural resource, and land-use planning agencies) committee that works to bring all partners together to focus on communication, participation & early involvement in Environmental Assessments & Environmental Impact Statements. The goal of CETAS is to provide input at major decision making points in projects, help Oregon DOT to develop & implement statewide environmental initiatives, etc, to reach environmentally informed decisions from the beginning stages of the project. CETAS also includes guidance assisting project teams to prepare proper data quality for effective analysis & decision support. GIS is a large component, with some of the info web-based, in order to ensure up to date & easily accessible information to project teams regarding environmental sensitive areas/areas of interest, etc (i.e. the Salmon Resources and Sensitive Area Mapping project).

  • Location: Alaska, Arizona, California, Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Maine, Michigan, Missouri, Montana, Nevada, New York, North Carolina, Oregon, Pennsylvania, Washington, Wisconsin, Multi-State

    Description: Matrix showing dozens of case studies from all over the United States that demonstrate effective practices in long-range and corridor planning, as well as linking planning and NEPA. Columns show which studies incorporate one or more of the following areas: Inter-agency coordination & consultation, mitigation, spatial data & tools, GIS, and process guidelines or changes.

  • Location: California

    Description: Use of repeatable, scientific approach for selecting mitigation sites and establishing conservation goals: An example of providing compensation prior to impacts is the Regional Advance Mitigation Planning (RAMP) effort in California (Thorne et al 2009). This innovative effort estimated potential future impacts to resources by developing a "footprint" of future projects, using that to identify resources that may be impacted, and then developing a method for identifying sites that could offset these particular impacts in a way that contributes to regional and statewide conservation priorities. This framework was tested in a subregion of the Central Valley near Sacramento, California. Once a list of the species and habitat types that would potentially be impacted in the region was identified, the locations of these species and habitats were mapped across the region and overlaid with many other data layers including ownership, land cover, species habitat, minimum size of habitat, priority conservation areas, etc. to evaluate each parcel's contribution to restoring potentially impacted ecological components. MARXAN was used to evaluate each parcel and identify the ones with the most potential for high quality compensatory mitigation. Some of the resources that were identified for compensatory mitigation included vernal pool complexes, Giant Garter Snakes, and Burrowing Owls. Although this type of "systematic planning of ecological offsets" has been demonstrated in other publications (Kiesecker et al. 2009), this project illustrated an effective process that "integrated the mitigation needs of more than one infrastructure agency."

  • Location: San Diego, California

    Description: The EMP is a unique component of the TransNet Extension in that it goes beyond traditional mitigation for transportation projects by including a funding allocation for habitat acquisition, management, and monitoring activities as needed to help implement the Multiple Species Conservation Program (MSCP) and the Multiple Habitat Conservation Program (MHCP). This funding allocation is tied to mitigation requirements and the environmental clearance approval process for projects outlined in the Regional Transportation Plan (MOBILITY 2030).

  • Location: Colorado, New Mexico, Wyoming

    Description: (from Executive summary): The Southern Rocky Mountain (SRM) region has one of the fastest growing human populations in the country, and also has numerous species/ecosystems of concern including 184 endemic species, 100 G1-G2 species, & 23 federally threatened or endangered. The ecological assessment conducted was a science-based (both fine & coarse scale) approach to design a portfolio of conservation areas.

  • Location: California

    Description: Description of Road and Rail Alignment Optimization software that can be used to quickly find the best placement and alignment for transportation corridors based on the potential environmental, social, and economic impacts. 14.5 minute video:

  • Location: Indiana, Ohio

    Description: In this case study documenting the realignment of USA24 between New Haven, Indiana and Defiance, Ohio, the thorough analysis of the preferred route is explored. A three step process was used to select the preferred alternative route. In step I, 26 feasible alternatives were analyzed to determine if they met the established purpose and need of the project. In step II, because no one alternative seemed ideal, Ohio DOT divided the corridor into 10-mile segments and considered stakeholder comments for each region. In the final step, a more detailed examination of impacts, such as environmental, was conducted.

  • Location: Oregon

    Description: This paper describes "a site selection model with two important conservation objectives: maximize expected number of species represented, and maximize the likelihood that a subset of endangered species is represented. The model uses probabilistic species occurrence data in a linear-integer formulation solvable with commercial software. The model is illustrated using probabilistic occurrence data for 403 terrestrial vertebrates in 147 candidate sites in western Oregon, USA. The trade-offs between objectives are explicitly measured by incrementally varying the threshold probability for endangered species representation and recording the change in expected number of species represented."

  • Location: Alabama , Arizona , California , Maryland, New Hampshire, New Mexico, New York, North Dakota, Oregon, Pennsylvania, Utah, Vermont, Virginia, Washington, Wisconsin

    Description: This website has 19 different examples of success stories, best practices, and/or innovative tools/approaches in integrating transportation planning and conservation.

Tools & Methods

Click on the arrows below for detailed information on each tool or method.

  • Description: BASINS is designed to be used by regional, state, and local agencies to perform watershed- and water-quality-based studies and as a system for supporting the development of total maximum daily loads (TMDLs). Version 3.1 is compatible with ArcView 3.1, 3.2, or 3.3. It is not compatible with the current ArcGIS suite of applications. Version 4.0 contains an installation program for use in an open source GIS program (MapWindow).

  • Description: Circuitscape is a free, open-source program which borrows algorithms from electronic circuit theory to predict patterns of movement, gene flow, and genetic differentiation among plant and animal populations in heterogeneous landscapes. Circuit theory complements least-cost path approaches because it considers effects of all possible pathways across a landscape simultaneously.

  • Description: CoastRanger MS has been designed to explain the consequences that different management approaches have on coastal processes, natural environments and flood and coastal erosion risk. The software highlights the range of interests that need to be balanced on the coast and demonstrates the difficult decisions that have to be made in some areas.

  • Description: CAPS is an ecological community-based approach for assessing the ecological integrity of lands and waters and prioritizing land for habitat and biodiversity conservation. The approach defines ecological integrity as the ability of an area to support biodiversity and the ecosystem processes necessary to sustain biodiversity over the long term. The approach assumes that by conserving intact, ecologically-defined communities of high integrity, most species and ecosystems can be conserved.

  • Description: EMDS integrates the logic engine of NetWeaver to perform landscape evaluations, and the decision modeling engine of Criterium DecisionPlus for evaluating management priorities.

  • Description: Envision is a GIS-based tool (beta version) for developing alternative-futures analysis used to model the landscape impacts of various policy scenarios on land use change and accompanying biophysical impacts. Strongest applications are mapping the cumulative effects of multiple actions at multiple sites as it tracks impacts over time. Has the ability to plug in evaluative models (e.g., credit calculators).

  • Description: The Conservation Fund's strategic conservation services use a green infrastructure planning approach-simultaneously focusing on the best lands to conserve and the best lands to accommodate development and human infrastructure-to help communities, state and federal agencies, and businesses balance environmental and economic goals through strategies that lead to smarter, sustainable land use; Green infrastructure plans: Development of comprehensive green infrastructure plans that identify community priorities and goals, inventory current community assets, map green space networks, develop strategies for implementation, and build capacity for communities to achieve their conservation visions; Decision support tool design and implementation: Integrate data, knowledge and analyses (e.g. ecosystem services, optimization, suitability analysis) to support land use decision making and prudent use of resources; Mitigation support: Identify and evaluate mitigation opportunities for agencies and business organizations from Habitat Conservation Plans, transportation improvement projects, military compatible- use buffer programs and pipeline/transmission/energy corridors.

  • Description: To aid managers in discerning the relationships between wildlife populations (for elk and mule deer) and habitat sustainability. The model produces a range of population values with related management implications (e.g., grazing, burning) that can be used in the planning process. Developed to resolve fence and forage conflicts on private and public lands. Quantitative output.

  • Description: Assess the quality and quantity of available habitat for selected wildlife species by comparing the same area at different points in time or by different areas at one point in time. Ordinal scale output.

  • Description: In metropolitan areas, urbanizing rural landscapes and most other development situations, the existence of multiple plans and many distinct government agencies and interest groups is normal, and should not be viewed as unusual or unexpected. The many plans that affect overlapping geographic areas are created by different stakeholders and are inconsistent in at least some respects, which is often seen as a problem. If we accept this situation as typical and expected, however, we can develop tools to treat these plans as an information system of plans (ISoP) and use them to advantage. The ability to access and compare multiple plans yields more information pertinent to making a decision than can be found in any one plan, which of necessity suppresses disagreement and multiple perspectives. The result is an ISoP that is a persistent, interactive and continually changing set of information that puts plans to work rather than on a shelf. Rather than pretending to create a new, consistent, overriding combination of these plans or "yet another plan" (YAP), the ISoP approach argues that planners should learn to work effectively with these many plans (Hopkins, 2001a, Hopkins, 2001b and Hopkins et al., 2005).

  • Description: PII is a protocol allows the user to evaluate potential development sites using checklists and rank them against a reference site. Objectives are to: (1) assist developers in deciding whether to proceed with development; (2) provide a procedure to determine pre-construction study needs to verify use of potential sites by wildlife; and (3) provide recommendations for monitoring potential sites postconstruction to identify, quantify, or verify actual impacts (or lack thereof).

  • Description: The Land Change Modeler (LCM) for Ecological Sustainability is an integrated software environment for analyzing land cover change, projecting its course into the future, and assessing its implications for habitat and biodiversity change. Commissioned by the Andes Conservation Biology Center of Conservation International, LCM is vertical application developed by Clark Labs and integrated within the IDRISI GIS and Image Processing software package. The Land Change Modeler for Ecological Sustainability is oriented to the pressing problem of accelerated land conversion and the very specific analytical needs of biodiversity conservation. LCM is organized into five areas: analyzing past land cover change, modeling the process of change, predicting the course of change into the future, assessing its implications for biodiversity, and evaluating planning interventions for maintaining ecological sustainability.

  • Description: LEAM urban land-use transformation modeling begins with drivers, those forces (typically human) that contribute to land-use change. Model drivers represent the dynamic interactions between the urban system and the surrounding landscape. Each driver is developed as a contextually independent sub-model which allows for calibration before being run simultaneously in the LEAM model. Environmental, economic and social system impacts of alternative scenarios such as different land-use policies, growth trends, and unexpected events can be tested out in the LEAM modeling environment. Scenario results and impact assessments can be displayed in a number of ways: as simulation movies, through a built-in mapping tool, in graph or chart displays, or simply as raw data. LEAM's visual representation of each scenario's outcome provides an intuitive means of understanding the potential of decisions and acts as a catalyst for discussion and communal decision-making. All driver models figure into creating the development probability model, while the impact models respond to the land use change that is triggered by the development probability model. Impacts assessed by the LEAM model are also used in the creation of sustainable indices and indicators that can feed back into the model drivers for new policy formation.

  • Description: Development of the Land Transformation Model (LTM) began in 1995 and is ongoing. The model uses landscape ecology principles, patterns of interactions to simulate land use change process, to forecast land use change. Though the model can be used in any definable region, precedence is given to watersheds as the spatial extent in LTM applications. Conceptually, the LTM contains six interacting modules: 1) policy framework 2) driving variables 3) land transformation 4) intensity of use 5) processes and distributions; and 6) assessment endpoints. The pilot model was developed for Michigan's Saginaw Bay Watershed and contains two of the six LTM modules; driving variables and land transformation. The pilot model integrates a variety of land use change driving variables, such as population growth, agricultural sustainability, transportation, and farmland preservation policies for the watershed.

  • Description: An HGM reference-based assessment restricted to depressional and riverine class wetlands located in Washington's western lowlands.

  • Description: Metroquest software allows a group to come to consensus on planning objectives (such as housing densities) and immediately see the future that can result for an entire metro region. MetroQuest offers customized mapping of client city-regions, as well as output tables demonstrating the performance in key indicator areas such as ecological footprints and commuting time, and the extent to which the region is meeting overall planning targets.

  • Description: MDOT initiated use of a geospatial site selection tool for strategic identification of ideal compensation areas - called the Wetland Mitigation Site Suitablity Index (WMSSI). This wetland mitigation tool allowed MDOT to analyze watershed trends in aquatic resources and subsequently rank possible mitigation sites by restoration potential; projected restoration value was measured based on hydric soils, historic wetlands, and topographic wetness data. The tool calculates composite suitability rankings by determining the weighted geometric mean of the environmental variables. Higher index values indicate more suitable locations. This technique builds on methods published by Van Lonkhuyzen (2004) and on the USFWS Habitat Evaluation Procedure (1981). The result of the WMSSI tool analyses in combination with a property selection tool integrates MDOTs methodology for acquiring real estate for mitigation sites with locations identified by WMSSI. The property selection tool includes criteria like size of parcel, adjacency to roads, existing wetlands and MI Dept of Natural Resource lands. "Under a project-by-project mitigation strategy, MDOT reported that staff commonly accompanied regulators on at least 4-5 site visits to determine the ecological suitability of potential restoration sites; now, MDOT's progressive approach to mitigation prevents consideration of less promising compensation sites and MDOT receives approval for around 95% of mitigation sites on their first site visit (Venner 2010). Over the past decade, Michigan DOT (MDOT) has transitioned from a traditional, project-by-project approach to aquatic resource compensatory mitigation, which coupled timelines and funds for wetland mitigation with individual transportation projects, to a watershed approach that separated compensation and transportation project funding. Allowing holistic consideration of wetland mitigation has permitted MDOT to achieve economies of scale via off-site, consolidated wetland mitigation sites, reducing per-acre compensation costs from typically exceeding $100,000, and generally falling between $75,000 and $150,000, to a present-day average cost of $25,000-$30,000 per acre (Venner 2010)." (cited from NCHRP 25-25, Task 67 report)

  • Description: The original 1992 version of MnRAM was developed to provide a practical assessment tool that would help local authorities make sound wetland management decisions as they assumed responsibility for regulating wetland impacts. The current version represents a more refined procedure that provides numeric, rather than the original descriptive, ratings. It may be applied to existing wetlands or potential restoration sites. Descriptive and ordinal scale output.

  • Description: The Ohio Rapid Assessment Method is designed to aid in the determination of wetland categories as defined in Ohio's Wetland Antidegradation Rule. The use of the Ohio Rapid Assessment Method should not be considered as a substitute, and is not intended to be a substitute, for detailed studies of the functions and biology of a wetland.

  • Description: To provide a technique that (1) assesses 4 major functions and 7 values of vernal pool wetlands, (2) is standardized and rapid (in the sense that the procedure can be completed in one day or less), (3) is well-documented with scientific literature, mainly from Oregon, and (4) can be used to prioritize vernal pool complexes and compare them before and after restoration or impact. Ordinal scale output.

  • Description: Provide a regional evaluation of the condition of wetland (river and lake) resources in order to aid in development of a watershed management plan. Nominal scale output.

  • Description: TransCAD is a GIS system designed specifically for use by transportation professionals to store, display, manage, and analyze transportation data. TransCAD combines GIS and transportation modeling capabilities. As a stand-alone GIS system, TransCAD has many of the standard GIS features: 2-D and 3-D visualizations, cartography, buffering, region/cluster grouping, spatial statistics and grid generation. Its strengths lie in the ability to create and model transportation networks and matrices, providing functions to develop an integrated Urban Transportation Planning System (UTPS). TransCAD comes in two versions, Standard (or Full TransCAD) and Base TransCAD depending on the desired tools and the budget of the user in a single integrated platform.

  • Description: The Unified Stream Assessment is a rapid technique to locate and evaluate problems and restoration opportunities within an urban stream corridor in Maryland.

  • Description: The Trust Fund helps make large-scale conservation possible. The program is able to implement large-scale watershed efforts that restore, enhance, and protect water quality through cost-effective, ecologically preferable projects. By using the Conservancy's conservation planning, projects are part of ongoing conservation initiatives with comprehensive ecological management plans.

  • Description: The Watershed Treatment Model (WTM), a simple spreadsheet-based approach that evaluates loads from a wide range of pollutant sources, and incorporates the full suite of watershed treatment options. In addition, the model allows the watershed manager to adjust these loads based on the level of effort put forth for implementation. Although the simple algorithms in this model are no substitute for more detailed watershed information, and model assumptions may be modified as the watershed plan is implemented, the WTM acts as a starting point from which the watershed manager can evaluate multiple alternatives for watershed treatment.

  • Description: Estimates wetland benefits of proposed wetland restoration projects submitted for funding under the Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA). The application in the plan formulation process is described in USGS (2006). Ordinal scale output.

  • Description: To allow a qualitative holistic evaluation of wildlife habitat for particular tracts of land statewide (Texas) without imposing significant time requirements. WHAP is intended to be used for (a) evaluating impacts upon wildlife populations from development project alternatives, (b) establishing baseline conditions, (c) comparing tracts of land which are candidates for land acquisition or mitigation, and (d) evaluating general habitat quality and wildlife management potential for tracts of land over large geographical areas. Ordinal scale output.