Environmental Impacts

The Natural Environment

Environmental resources have immeasurable benefits that affect social well-being and the long-term viability of local and regional economies. Transportation planning provides the opportunity to slow negative and costly environmental impacts. That opportunity lies in making transportation improvements that minimize adverse environmental impacts and – because transportation improvements can facilitate new development – in making changes to those conventional development trends and practices that contribute to the cumulative damage of environmental resources. Regional transportation planning offers the potential to result in better decisions for improving transportation and how development occurs, with related cost benefits.

OKI utilized an environmental consultation process to identify the environmental impacts of this 2040 Plan. In environmental consultations, metropolitan planning agencies consult with state and local conservation, environmental protection, and land use management agencies concerning the transportation plan’s development. These consultations involve a comparison of the transportation plan with environmental resources identified by the states for conservation or protection, which OKI calls Regionally Significant Resources (per 23 CFR Sec 450.322 [g]). This process expands participation in the transportation plan’s development and consideration of potential environmental effects and their financial implications.

Consultations are intended to result in better decisions for improving transportation. The consultations bring new insights to transportation planning and expand opportunity for transportation investments to advance sustainable development and reduce negative and costly environmental impacts. More specifically, they provide opportunity to consider:

  • The extent and vulnerability of the region’s least impaired environmental resources
  • The potential environmental effects of transportation improvements at the project level and from a larger and cumulative perspective
  • Options for avoiding project impacts that could result in mitigation and higher costs
  • Options for reducing adverse impacts from conventional development trends and practices

OKI designed consultations on the DRAFT 2040 Plan to include multiple opportunities for state and local agency participation and input. Between December 2015 and March 2016, opportunities included:


A webcast that introduced the consultations process and provided information on and access to data and map locations for Regionally Significant Resources and other natural resource data via OKI’s new online Environmental Resource Viewer (below on this page)


Online Survey

An online survey for collecting and updating information on how transportation is affecting environmental resources and how adverse effects are being addressed


Interactive Session

An interactive session that included a summary of survey results, consideration of “major environmental concerns,” presentations  on changing conditions and challenges to trees and streams and opportunity to review and comment on individual transportation projects through geographic-based breakout sessions with facilitators to operate the Viewer and guide discussion

Email Request

An email request for additional comment to all consultation participants

The 72 consultation participants represented every state and county in the region and a broad and diverse range of environmental and planning expertise. Participants were from 33 local agencies and 17 state agency divisions. Sixty participants responded to the survey and/or attended the session and an additional 12 people listened in on the webcast.

OKI’s Regionally Significant Resources were displayed on the OKI Environmental Resource Viewer along with the OKI 2040 Plan Draft Projects in early 2016 during the Plan’s development. Only projects that would result in the expansion of transportation system capacity or an increase in the physical infrastructure footprint were examined in the Environmental Consultation Process.

Environmental Consultations Outcome

As described above, in OKI’s environmental consultations, participants provided information on environmental impacts from transportation and related development survey responses, presentations and discussion. These included concerns about impacts from transportation-related sources, impacts to Regionally Significant Resources, potential impacts from proposed transportation projects, impacts that are “major environmental concerns” and strategies for reducing project-level environmental impacts.

Transportation affects environmental resources through the impacts of roadway runoff, project construction, new development facilitated by transportation improvements and increased impervious surface. These impacts can be direct and short-term, or they can be cumulative as the result of repeated or long-term effects. The below list summarizes the concerns consultation participants identified about how transportation-related impacts affect environmental resources.

  • Roadway Runoff
  • Transportation Project Construction
  • New Development that Occurs as a Result of Transportation Improvements
  • Increased Impervious Surface
  • Impacts to Trees
  • Impacts to Streams

A complete list of environmental consultation participants’ review comments regarding the OKI 2040 DRAFT Project List can be found HERE. In addition, a summary of responses to a survey question asking about additional “major environmental concerns” is available HERE.

The major concerns about environmental impacts include:

  • Retain forested tracts
  • Conserve stream corridors
  • Divert roadway runoff from direct entry into streams
  • Protect streams not already degraded
  • Constrain the growth of impervious surface
  • Manage stormwater to reduce its detrimental impacts on stream channels and aquatic life

Strategies for Reducing Project-Level Environmental Impacts

Options for better addressing project-level impacts were considered in the environmental consultations process through inquiries about the progress, importance and feasibility of sixteen strategies that had been suggested in previous consultations. Based on responses, half the suggested strategies are making moderate progress and slightly less than half are making low level progress. Survey results are not conclusive but provide perspective, serve as indicators and can guide further investigation or initiatives. The strategies reviewed in the survey are listed below.

Options for reducing impacts through better transportation and development planning include these strategies:

  • Keep transportation projects out of the floodway
  • Keep project fill out of the floodway
  • Avoid Agricultural Districts
  • Overlay resource data with transportation project locations early on / Obtain information on potential mitigation needs as soon as possible
  • Use compact or conservation development in developing areas
  • Apply the same stormwater management standards to state transportation projects as to local projects

Options for reducing impacts through better project design and construction include these strategies:

  • Increase the use of pervious pavement treatments
  • Acquire or expand right-of-way to allow for green infrastructure/best management practices
  • Reduce the use of culverts / Design roadways and bridges to span streams or floodways and/or discharge runoff to land surface
  • Increase the use of swales, detention basins and roadside ditches
  • Increase the use of exfiltration treatment in curb-and-gutter systems (where right-of-way is limited and streams need protection)
  • Reduce stream piping / Increase day-lighting of streams

Options for reducing impacts by improving roadway maintenance and right-of-way management include the following strategies (all rated as having slow progress):

  • Manage roadway rights-of-way to protect and enhance environmental resources
  • Use less road salt / Increase the use of road salt alternatives
  • Conduct less mowing and/or use native plantings in rights-of-way
  • Plant more trees in the rights-of-way

A Basis for Moving Forward

For consultations now and in the future, the underlying issue to consider is how the region can develop while better maintaining its environmental resources. This same issue is addressed in policies for sustainable development and environmental stewardship in the OKI Strategic Regional Policy Plan. The need is for development to occur differently so that costs can be reduced from adverse environmental impacts and unintended consequences. State and local governments help determine how the transportation system grows and how its development impacts are managed.

  • Outlying areas with most of the region’s least degraded environmental resources have the opportunity to put measures in place to avoid or reduce the environmental and financial consequences associated with traditional development.
  • Developed areas with impaired environmental resources can identify opportunities to use transportation improvements, re-development projects and stormwater management to restore environmental resources and revitalize communities – to remove streams from pipes, replace gray infrastructure with green infrastructure for infiltrating runoff, restore trees and native vegetation, and set development back from the stream edge.

The economic angle of environmental protection was summed up by one participant in earlier consultations as, “Protection is in the interest of the pocketbook — the cost of replacing or restoring natural resources should make it a no-brainer to see the need to protect them.”

State and local agency actions that can reduce public sector costs include:

  • Transportation improvements that do not require mitigation
  • Development that avoids impacts to Regionally Significant Environmental Resources
  • Development and stormwater management practices that reduce environmental impacts
  • Initiatives to more effectively conserve high-quality and scarce resources
  • Public policies and development processes that better account for environmental resource values

As evidenced in OKI consultations, public agency initiatives and capabilities are key to reducing adverse and costly environmental impacts that can occur from transportation improvements and related development, and their actions will determine how the region moves forward towards maintain the viability of its environmental resources.