Land Use and the Natural Environment
Transportation System Affects Built, Natural Environments
The transportation system’s purpose is to move people and goods from one place to another. In doing so, transportation systems affect community character — the natural and built environment, and economic development patterns. This system can improve the economy, shape development patterns, and influence quality of life and the natural environment.


Economic Development
Transportation investments often contribute to economic growth. Beyond land use improvements, successful business retention and recruitment activities, for example, can generate demand for capital investments in new or upgraded transportation facilities and/or services. Economic development efforts that help shape employment or commercial centers also shape commuting and travel patterns.
Land development and most economic development projects depend on the availability and adequacy of transportation facilities and services.
Other public facilities and services, such as water capacity improvements; sewer capacity improvements; stormwater management; greenspaces; and school capacities, also have an impact on a community’s ability to accommodate land use changes. The timing, location, and cost of water, sewer and road facilities can have a significant impact on land use patterns. The density and intensity of land development are influenced by the availability and adequacy of these public facilities and services. Land use changes, in turn, create a greater or lesser need for roads and public transit.


OKI and Federal Guiding Plans
OKI’s Strategic Regional Policy Plan encourages land use patterns that promote multimodal travel and the efficient use of land, natural resources, and public facilities and services.
The US Department of Transportation Federal Highway Administration provides PlanWorks as a guide to aid transportation planning agencies, with the goal to help streamline decisions throughout long-range planning processes. This guide’s applications component includes a series of relevant topics that provide specific information, and approaches for how these topics can be considered in a collaborative decision-making framework. OKI maintains a Strategic Regional Policy Plan encompassing topics of the PlanWorks Applications.
The OKI Strategic Regional Policy Plan – How Do We Grow From Here?
Due to the inseparable connection between transportation and land use, the role of the OKI Board is to develop the Strategic Regional Policy Plan (SRPP). Importantly, the SRPP recommendations must be integrated into the region’s transportation project prioritization process. This plan incorporates, by reference, the Strategic Regional Policy Plan Goals, Strategic Issues, Objectives and Policy Recommendations, as adopted in September 2014.
The How Do We Grow From Here? — Strategic Regional Policy Plan contains a vision for regional vitality, sustainability, and competitiveness, focusing on the land use–transportation connection.
- Where are we as a region?
- Where are we going given current trends?
- Where do we want to go?
- How do we get there?
- Transportation
- Public Facilities
- Housing
- Economic Development
- Land Use
OKI Strategic Regional Policy Plan in Action
Through Consultation – The OKI Regional Planning Forum
Implementation of many SRPP recommendations is determined by the affected jurisdictions and other organizations on a voluntary basis. For that reason, OKI continues to build relationships and consultations that were key to developing the SRPP and are essential for its implementation.
The types of groups that are or will be consulted include state and federal regulatory agencies; state and local agencies responsible for land use management, natural resources, environmental protection and conservation agencies; local planning and major economic development agencies; local emergency management agencies; and local agencies that promote transit and alternatives to the single-occupant automobile.
The OKI Regional Planning Forum strives for a continued dialog to occur in the region surrounding the SRPP policy recommendations, and to ensure the dialog involves the vast array of stakeholders necessary to implement the SRPP. The forum is a regional outlet for sharing information, experience and expertise among planners and those in related disciplines. It is open to representatives throughout the Tri-state region who are working to affect the future. This would include local planning and community foundations that plan for community development, business, workforce development, public housing, environmental issues, efficient food systems, public transportation, energy, tourism, social services, or public health — in short, any issue that affects either the built environment or natural environment.
Through Comprehensive Planning Assistance
The classic first-level planning tool is the local comprehensive plan. The local comprehensive plan addresses all aspects of land development, including traffic circulation, bicycle and pedestrian access, economic development, public facilities, housing, natural resources, recreation, intergovernmental coordination and capital budgeting.
Local comprehensive plans can improve regional transportation through land use planning and development strategies that help reduce single-occupant vehicle trips, reduce trip length and increase modal choices. These plans are treated differently by state laws in Ohio, Kentucky and Indiana. Ohio law mandates a comprehensive plan as a prerequisite to zoning and subdivision regulation, but provides no requirements or guidance as to content or updates. Kentucky law requires a regularly updated comprehensive plan as a prerequisite to zoning and subdivision regulation, and includes detailed guidelines for comprehensive plan preparation. Indiana law permits comprehensive planning and provides a list of what may be included in the plan.
Comprehensive plans should be implemented through local regulations and incentives, such as zoning and subdivision regulation, that are consistent with such plans. To measure the state of planning in the OKI region, OKI maintains an inventory of local comprehensive plans adopted by political jurisdictions that exercise zoning authority. Of the 143 applicable jurisdictions, 106 (or 74 percent) have adopted a comprehensive plan. Forty-seven communities have plans that were adopted fewer than five years ago. This represents about a third, with the other two-thirds in need of updating their plans to be considered a current plan by OKI’s prioritization process definition.
When requested, OKI provides technical assistance to communities in the region as local comprehensive plans are created, updated or maintained. OKI maintains the Elements of an Effective Local Comprehensive Plan to serve as a guide for local governments in the region. OKI staff has provided technical support to several communities in the region and will continue to provide this service.
Through Consistency
One way the SRPP and this regional transportation plan strive to improve consistency with planned growth and development patterns is to encourage better comprehensive planning at the local level. When local governments base their future land use and transportation needs on sound data and analyses — and a better understanding of the implications of alternative development patterns — OKI is able to be more proactive when planning for transportation improvements on the regional scale.
Perhaps most significant: OKI has utilized the prioritization process for regional transportation investments (STP, TA and CMAQ programs) to incentivize project consistency with the goals and recommendations of the SRPP. Of the total points that can be awarded when transportation projects are evaluated and scored, 10 points are based directly on the projects consistency with the SRPP. Up to five points can be awarded for projects addressing strategic regional issues identified by the SRPP, such as, projects located in areas with mixed land uses or enhancing mixed land uses, projects serving brownfield or greyfield properties where infrastructure is underutilized and for projects using techniques to minimize or offset environmental impacts, including the use of green infrastructure strategies. Another five points are awarded for projects consistent with a community’s current comprehensive plan. These points can provide an important advantage for these projects in the prioritization process.
OKI will continue to encourage local planners to engage in proactive planning processes and to make the transportation elements of their local comprehensive plans consistent with the regional transportation plan and the Transportation Improvement Plan (TIP).
Through Tools: Estimating Public Costs and Fiscal Impacts
Another aspect of promoting consistency between planned transportation improvements and local growth patterns is to consider the likely public costs and fiscal impacts of proposed land use changes on public infrastructure and public services. Decisions on land development, redevelopment and improvements to public facilities and services should be made with a clear understanding of their fiscal impacts to individual communities and the region.
It is most economical to provide adequate public facilities and services concurrent with the impacts of development. Retrofitting adequate public facilities and services in response to growth is typically more expensive than directing or managing growth with public investments. The SRPP addresses the need for communities to have a more complete understanding of the public costs and benefits associated with development proposals.
OKI developed and maintains the Fiscal Impact Analysis Model (FIAM) to aid local governments wanting to analyze benefits and fiscal consequences of land use changes within their communities. The FIAM assesses the costs and revenues associated with land use activities and their existing and potential impacts on community budgets. These estimates help communities anticipate and plan for current and future costs of growth. As communities better understand associated costs and revenues of development through fiscal impact analyses, they will be better able to plan for transportation investments to serve new development or address existing deficiencies.
OKI’s model was initially tested by 10 communities. OKI has provided assistance in applying the FIAM tool and its principles to several additional communities since the 2010 program launch, and continues to maintain and improve this vital tool.

Leadership – Addressing Emerging Issues
Energy is a topic that affects every household, business, and organization in a community. Yet, it’s so ever-present that it’s often taken for granted. Energy is rarely featured as a topic in communities’ strategic or comprehensive plans. Because of this, local priorities regarding energy remain largely unexplored. To address this, OKI has produced Community Strategic Energy Plans for eight interested local communities.
OKI worked with each community to:
- Identify concentrations of inefficient building stock and the most cost-effective improvements to apply to each;
- Gauge local energy burden, which is the percentage of household income spent on energy;
- Benchmark community-wide energy use by land use/economic sector and by energy type;
- Understand the resiliency of local energy infrastructure and how susceptible the community’s infrastructure is to disruption;
- Analyze their urban heat island effect;
- Conduct energy audits of selected local government facilities;
- Analyze the capacity of energy infrastructure to accommodate planned growth;
- Develop locally generated goals and strategies with meaningful public input; and
- Identify existing energy efficiency programs that support local goals.
We have come to understand that things work better when our regional transportation priorities and local land use priorities are mutually aligned. The same holds true for our energy policies and infrastructure. By developing a locally-driven set of energy priorities, local communities are able to effectively communicate them to everyone involved in their community development activities to best advance and capitalize on rapidly changing technologies and navigate any changes in utility regulations.
Considerations Related in Land Use
Demographic Impacts on Land Use
Future trends in land use demands and development patterns are best predicted by considering the needs and likely preferences of our future population. Although it is impossible to precisely predict these preferences, we can examine our current population and forecast future land use trends based on future housing and transportation needs. Understanding what our future population’s housing, shopping and commuting needs are provides a basis for understanding what our long-range planning needs.
As described in this plan’s population section, there are changes projected for the region’s age composition in 2050. Although the percentage of all age groups under age 65 will be stable or lower in 2050, the oldest age cohort of 65 or over will grow by five percent. This age cohort has unique transportation and land use needs that will likely increase demand for certain development patterns.
Public Health and Community Character
The most recent additions to the OKI Elements of an Effective Local Comprehensive Plan include Public Health and Community Character. The purpose of the Public Health Element is to improve the overall health of communities by encouraging active, healthy lifestyle choices through land use decisions and the availability of active multi-modal transportation options.
Community Character encompasses aspects ranging from historical structures and landmarks, natural features, landscapes and streetscapes to patterns of development. These additions correspond with FHWA’s PlanWorks Application topics Health in Transportation and Human Environment and Communities as they inform local community level and regional transportation projects and initiatives.
Transit Friendly Land Use and Development Patterns
Elderly populations benefit from having more transit options. As people age, having choices for travel, other than driving a car, are more appealing and necessary. Land use and development patterns have an impact on the viability and likelihood of transit as a transportation mode. Higher densities and walkable development patterns in growing and infill areas can make transit more feasible. This is done by creating destinations and concentrated populations that may choose to use transit as an alternative to single-occupant automobile trips.
Transit development plans can facilitate the design of a system that incorporates multiple modes of transit service, links stations/stops and adjacent land uses and integrates station/stops into neighborhoods. The recommendations of transit development plans typically focus on the desired outcomes of transit-friendly development, including accessibility, walkability and interconnectivity and high levels of ridership.
Transit’s use by any age group in the next 30 years will be altered by the introduction of autonomous vehicles (AV) and their potential to encourage ridesharing among strangers. The mobility advantages of AVs will be of particular benefit to those who currently lack mobility. This would include the elderly. AVs will be best utilized if they are integrated into the transit options of communities.
Enhancing Travel and Tourism
The FAST Act expanded the scope of consideration for metropolitan planning processes to consider projects and strategies that will enhance travel and tourism. Tourism and recreational activities pose many similar travel considerations, which typically differ from commuter travel and commercial transport issues. The 2004 National Academies of Sciences, Engineering, and Medicine’s Integrating Tourism and Recreation Travel with Transportation Planning and Project Delivery report explains the relationship between tourism and transportation is that tourism is a generator of travel demand and the transportation system provides access to major tourist attractions.
This report points out that transportation can be a critical element of the operation of visitor attractions and effective transportation planning can balance the traffic needs of different traveler groups during peak tourism seasons or special events. These relationships provide a common base of interest for transportation and tourism agencies and are thus the motivation for interagency coordination. The key to addressing these common interests (and their ultimate implementation) is the development of effective processes for coordination between various transportation agencies, tourism agencies, other planning organizations, and private-sector interests.
To understand tourism demands on the region’s transportation system, OKI compiled an inventory of assets in 2019. This inventory includes 93 tourism destinations, 47 season events, and 167 recreational destinations. OKI then engaged 18 tourism agencies, including state and local visitors bureaus and park agencies across the region to provide perspective on how these destinations and events are served by the transportation system and what concerns tourism professionals may have. The highest concern is access and connectivity between tourism destinations. The survey results for each agency is summarized in the table below.
The OKI Transportation Alternatives (TA) program also provides opportunity for system investments in projects that enhance accessibility to and within many of the tourism destinations identified. Refer to the Active Transportation chapter of this plan for more details regarding the TA program. OKI will continue to consult with tourism officials to inform transportation and regional planning initiatives, as appropriate.
Environmental Considerations
The Natural Environment
Environmental resources have immeasurable benefits that affect social well-being and the local and regional economies. The term “environmental resources” as used here encompasses natural systems and natural resources and can include areas defined as greenspace or as green infrastructure.
- The occurrence of high-quality or rare environmental resources — such as clean streams, productive aquifers, aesthetic open space or forested hillsides — are economic assets that help sustain and can attract new development.
- The existence of impaired resources results in increased costs. Costs may be associated with damage or mitigation related to an individual project. The more significant cost of impaired resources, however, is the financial effect of cumulative damage over extended time, such as costs related to flood protection, repair of flood damage and higher levels of water treatment. As high-quality resources in metropolitan areas become scarcer, project and mitigation costs are expected to increase.
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.
It establishes procedures for considering the environmental effects of proposed federal actions so that environmental factors are weighted equally with other factors in federal decision-making. The policy of environmental stewardship is further strengthened by federal legislation such as the Clean Air Act, Clean Water Act and Endangered Species Act and by federal initiatives such as the Federal Highway Administration’s (FHWA) process for Planning and Environmental Linkages (PEL) and PlanWorks guidance.
At a regional level, OKI’s progress in protecting environmental resources includes the implementation of the Strategic Regional Policy Plan, several OKI water quality management programs and initiatives in greenspace planning. The OKI Environmental Consultations process is used to inform the long range transportation planning process, transportation prioritization and the Environmental Resource Viewer; all employ and encourage the FHWA concept of advanced mitigation. By identifying potentially negative and costly environmental impacts early in the planning process, more efficient, effective and timely NEPA reviews can be facilitated by local, state, and federal agencies in connection with projects recommended in the OKI plan.
Your Title Goes Here
Transportation Planning’s Consideration of Environmental Effects
Environmental considerations are an integral part and increasingly important element of transportation planning. The need to protect environmental resources as part of the process for improving transportation is clarified in FHWA policy, integrated into project-level planning and has been progressively strengthened in regional transportation planning.
FHWA policy clarifies that environmental considerations are to be integrated into every phase of transportation decision making (1994 Environmental Policy Statement) and that “Metropolitan Transportation Planning should include consideration of the protection of important natural ecosystems and biological resources…” and provide for “incorporation of ecological considerations early in the transportation system planning and development process” (1995 FHWA policy memorandum). FHWA, with assistance by seven other Federal agencies, prepared Eco-Logical: An Ecosystem Approach to Developing Infrastructure Projects to promote and facilitate ecosystem-based planning and mitigation across agency and disciplinary boundaries in order to develop more cost-effective transportation projects with better environmental outcomes.
In 2005, new transportation legislation (SAFETEA-LU) added two new requirements to regional transportation planning for agencies like OKI. One requirement calls for “environmental consultations” to bring state and local agencies involved in conservation and environmental protection more fully into the transportation plan’s development. The other requirement calls for the plan to include “a discussion of potential mitigation of environmental effects,” which involves consulting with federal and state agencies on types of strategies for avoiding, minimizing or compensating for transportation effects.
OKI Environmental Consultations
To ensure that OKI meaningfully engages agencies involved in conservation and environmental protection, state and local experts are convened to consider the projects in this plan. This process has evolved with each plan since 2012 and is refined based on the input received in previous consultations. The process for this round of Environmental Consultations included the following:
• An Environmental Consultations overview with training on how to access and use the online Environmental Resources Viewer Application.
• Survey feedback received from state and local agencies on how to better protect environmental resources from any negative transportation or development impacts.
• A map-based comparison of the proposed transportation plan projects with environmental resources that states have targeted for protection or conservation.
Discussion of Environmental Mitigation
OKI is responsible for developing a Discussion of Environmental Mitigation as part of its regional transportation planning. The discussion considers potential mitigation activities and areas for their application that are regional in scope, and that may have the greatest potential to restore and maintain the environmental functions affected by the regional transportation plan. Part of the Environmental Consultations engagement process focuses on this discussion and is included in the Environmental Impacts chapter of this plan.
Additionally, OKI staff continues to refine environmental prioritization data. This information is used by local conservation partners and local governments as they prioritize where their conservation efforts should be focused. This information can also help identify potential mitigation sites for future transportation and development projects. Ongoing consultation with greenspace experts, including the Green Umbrella Land Prioritization Impact Team, enables OKI tools and data to remain at the forefront of related discussions and planning efforts.
Air Quality
Congress adopted the Clean Air Act Amendments (CAAA) in 1990 to address the country’s major air pollution problems. The CAAA regulates six pollutants: sulfur dioxide, nitrogen dioxide, lead, carbon monoxide, particulate matter and ozone. Under provisions of the CAAA, the U.S. Environmental Protection Agency (EPA) designated nine counties in the Cincinnati area as a nonattainment area for ozone under the 2015 ozone standard. Nonattainment means that the area is not meeting the national ambient air quality standard. Ozone is formed through chemical reactions induced when sunlight reacts with volatile organic compounds, or VOC’s, and oxides of nitrogen (NOx). VOCs and NOx occur from incomplete combustion of fossil fuels.
In April 2018, the U.S. Environmental Protection Agency (EPA) designated portions of nine counties in the Cincinnati area as a nonattainment area for ozone under the 2015 ozone standard. The 2015 Cincinnati ozone nonattainment area is Lawrenceburg Township in Dearborn County, Indiana, portions of the Kentucky counties of Boone, Campbell and Kenton, and the Ohio counties of Butler, Clermont, Clinton, Hamilton and Warren.
Transportation-related sources are a major contributor to the above CAAA-regulated pollutants.
Transportation sources account for nearly one-half of total regional emissions of VOC’s and one-third of NOx emissions. Industry sources account for about another one-third of all VOC and NOx emissions. The remaining “area” sources include individually insignificant sources that, when added together, have a significant impact, such as lawnmowers, oil-based paints, boats and dry cleaners.
Following progress in reducing fine particle pollution, the region has attained the annual PM2.5 standards. The area must continue to maintain the standards, keep previous regulatory commitments and continue to demonstrate transportation conformity. PM2.5 refers to a complex mixture of fine particulates, primarily from fossil fuel combustion. PM2.5 is emitted directly and will also form indirectly through reactions with precursor emissions, especially NOX. A primary contributor to transportation-related PM2.5 is diesel emissions.
Greenhouse Gases
Although not an EPA-regulated pollutant under the CAAA, emissions of greenhouse gases have been linked to global climate change. Utilizing a travel demand model and EPA’s latest emission model, OKI forecasts future greenhouse gases, ozone and PM2.5 emissions from transportation sources through 2050. These forecasts were made in spring 2020 and reported in the environmental impacts section of this plan.
FHWA Alternative Fuel Corridors
In 2017, FHWA designated alternative fuel corridors in the OKI region for electric vehicles (EV), liquefied natural gas (LNG) and compressed natural gas (CNG). (Insert Table) I-275, I-71, and I-75 received EV signage ready designations; I-71 and I-75 received CNG signage ready designations; and, I-75 received the LNG signage ready designation. With the designation of alternative fuel corridors, FHWA is establishing a national network of alternative fueling and charging infrastructure along national highway system corridors. FHWA based corridor designation selection on criteria that promotes the “build out” of a national network.
FHWA intends to support the expansion of this national network through a process that develops national signage and branding to help catalyze applicant and public interest; encourages multi-State and regional cooperation and collaboration; and, brings together a consortium of stakeholders including state agencies, utilities, alternative fuel providers, and car manufacturers to promote and advance alternative fuel corridor designations in conjunction with the Department of Energy. OKI will continue to facilitate these collaborations and strive to advance alternative fuel infrastructure, as appropriate.
FHWA Designated Alternative Fuels Corridors (Ohio, Kentucky, Indiana)
EV Ready1
- I-275: Entire length
- I-71: From Mason, OH to the I-71/I-75 split near Walton, KY
- I-75: West Chester Township, OH to the I-71/I-75 split near Walton, KY
CNG Ready2
- I-71: From I-71/I-75 split near Walton, KY to Cleveland, OH
- I-75: From I-71/I-75 split near Walton, KY to Piqua, OH
LNG Ready3
- I-75: From I-71/I-75 split near Walton, KY to Vandalia, OH
Source: FHWA
Planning for Resiliency
In 2012, Moving Ahead for Progress in the 21st Century Act (MAP-21) built upon earlier programs and policies, promoting accelerating project delivery through the increased use of innovative approaches and the Planning and Environmental Linkages (PEL) process. In 2015, with the passage of the Fixing America’s Surface Transportation (FAST) Act, MPOs continue to be encouraged to consult with officials responsible for other types of planning activities. It adds to the list of such activities as tourism and the reduction of risk of natural disasters.
The FAST Act expands the focus on the resiliency of the transportation system as well as activities to reduce stormwater runoff from transportation infrastructure. In addition, it newly requires strategies to reduce the vulnerability of existing transportation infrastructure to natural disasters.
Extreme weather events, such as, prolonged heat waves, major rain and snow episodes and flooding have impacts on both maintaining and planning transportation infrastructure. While opinions vary on climate change and its causes, historical data indicate an increasing need to plan for transportation resiliency from weather impacts. For that reason, in 2016 the Ohio Department of Transportation (ODOT) contracted with the Resource Systems Group to prepare the Ohio DOT Infrastructure Resiliency Plan, a study of climate change and extreme weather effects in Ohio to enable planning for transportation system resiliency on a state scale.
Rising temperatures can affect transportation infrastructure in a variety of ways, including: freeze-thaw cycling that can compromise pavement integrity; thermal expansion in bridge joints; reduced soil permeability, increasing surface run-off; and lengthening the construction season. Increasing heavy precipitation events can affect transportation infrastructure by flooding roads and bridges; causing soil erosion and slumping; increasing soil moisture build-up behind retaining walls and abutments; creating scour action at bridge piers and abutments; and compromising pavement integrity.
In the ODOT report, several data sources were examined, including the 2013 National Climate Assessment. This data indicated that Midwest temperatures increased by about 1.5 degrees Fahrenheit since 1895, with more than 80 percent of the change occurring since 1980, and that the warmest 13 years since the 1860s have occurred since 1990. All seasons in the Midwest are experiencing temperature increases with the most rapid rises in spring and winter. There have been 45 new daytime highs recorded since 2000, many of which are in mid-March to mid-April.
Additionally, five of the twelve warmest summers since 1895 have occurred since 2000. Since 1900 average annual rainfall in Ohio has increased from 37 inches to 40 inches, an 8 percent rise, with a significant portion of the precipitation increase occurring in extreme events such as 100-year storms.
The Kentucky Transportation Cabinet (KYTC) Transportation System report Vulnerability and Resilience to Extreme Weather Events and Other Natural Hazards — Final Results of Vulnerability Assessment of National Highway System for All KYTC Districts addresses issues relating to climate change. The Midwest Regional Climate Center, using historical climate data at the county level, found geographical patterns of extreme precipitation and extreme heat across the state. National Climate Development and Advisory Committee climate protection scenarios project an increase across the state in the annual number of days with a maximum temperature above 95 degrees, and an increase across the state in the annual number of days with extreme precipitation.
The KYTC report also addresses climate inter-annual variability in weather going forward. Furthermore, the KYTC report also addresses risks due to seismic activity and landslides. The risk of earthquakes is lower than the rest of the state, and would not be expected to negatively affect assets but could contribute to landslides in the area. Kentucky Geological Survey (KGS) documented landslides are abundant in Northern Kentucky, particularly Campbell and Kenton Counties.
Purdue University recently published Maintaining Indiana’s Urban Green Spaces: A Report from the Indiana Climate Change Impacts Assessment, which projects that Indiana will become wetter and warmer, and continue to intensify each through the end of this century. Increased green infrastructure is recommended to provide shade, evaporative cooling and windbreaks thus saving residential electrical and heating costs, and they help to avoid carbon dioxide emissions annually.
Green infrastructure plays an essential role in urban air quality, too. It was estimated that Indiana’s urban trees removed 8,400 tons of air pollution in 2010, at a value of $63 million. Urban trees and other vegetation increase the amount of porous ground that can take up rain and melting snow and keep water from overburdening storm sewers. It is estimated that urban trees provide about $24 million in stormwater management benefits to the state annually. Riparian buffers, bioswales, rain gardens and other green drainage infrastructure can also retain or redirect precipitation that would otherwise travel over impervious surfaces to storm drains.
The Ohio River Basin Climate Change Project provides the OKI region with additional information on climate projections. In 2015, James Noel of the National Oceanic and Atmospheric Administration, National Weather Service, delivered a presentation to the OKI Groundwater Committee. This project was undertaken as a joint effort among several national and regional organizations, including the U.S. Army Corps of Engineers (USACE), the National Oceanic and Atmospheric Administration, U.S. Geological Survey, U.S. EPA, the Battelle Institute, Marshall University and the University of Cincinnati. The USACE Institute of Water Resources evaluated more than 75 climate model forecasts for future temperatures and rainfall, and used forecast periods of 2011 to 2040; 2041 to 2070; and 2071 to 2099.
Nine climate forecast scenarios were used that best represented the 75-plus climate forecasts, and the climate models were run from 1952 to 2099. Retrospective runs of the 1952 to 2001 climate and river model made it possible to compare the model results with actual data from the same period, and the correlation between the retrospective model runs and actual data was within two percent on an annual basis; a good correlation for future predictions. Over the course of the multi-year forecast periods, all the scenarios indicate a general increase in temperature, with a range of 10 to 35 percent for the increase, and all the scenarios indicate a general increase in precipitation, increasing from the average of 40 inches annually received now.
When the climate is warming, there is more variability in the system, and the results for autumn show the greatest variability. Modeling results indicate mean, minimum and maximum stream flows within the historical range through 2040, except during autumn. Beyond 2040, mean and maximum stream flows are projected to increase by a range of 10 to 40 percent, which means that until 2040, flood volumes are expected to follow past patterns while larger floods are predicted after 2040.
In terms of temperature trends, the modeling indicates that the Ohio River Valley will gain about 0.5 degrees Fahrenheit per decade and then about one degree per decade from 2050 to 2099. More rapidly increasing temperatures would likely lead to increasing evapotranspiration, which would further increase climate uncertainty. In general, the modeling indicates that by the end of the 21st century, average temperatures now experienced in areas along Interstate 64 south of the Ohio River Basin will shift to being experienced along Interstate 70 north of the Ohio River Basin.
A review of temperature and precipitation trends since 1976 indicates that most observed warming has been in winter in the Ohio Valley and that most observed increases in precipitation in the Ohio Valley have been occurring from late summer into autumn and early winter. Overall, the climate models used in the Ohio Valley project also suggest that beyond 2040, minimum stream flows would decrease in autumn and beyond 2070 they would decrease annually as well.
Green Infrastructure and Innovative Natural System Design
Section 502 of the Clean Water Act defines green infrastructure as “… the range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters.”
The US EPA describes green infrastructure as a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits. While single-purpose gray stormwater infrastructure—conventional piped drainage and water treatment systems—is designed to move urban stormwater away from the built environment, green infrastructure reduces and treats stormwater at its source while delivering environmental, social, and economic benefits.
Stormwater runoff is a major cause of water pollution in urban areas. When rain falls on our roofs, streets, and parking lots, the water cannot soak into the ground as it would naturally. Stormwater drains through gutters, storm sewers, and other engineered collection systems and is discharged into nearby water bodies. The stormwater runoff often carries trash, bacteria, heavy metals, and other pollutants from the urban landscape. Higher flows resulting from heavy rains also can cause erosion and flooding in urban streams, damaging habitat, property, and infrastructure.
When rain falls in natural, undeveloped areas, the water is absorbed and filtered by soil and plants. Stormwater runoff is cleaner and less of a problem. Green infrastructure uses vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments. At the city or county scale, green infrastructure is a patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the neighborhood or site scale, stormwater management systems that mimic nature soak up and store water. (Source: The US EPA)
OKI considers many environmental aspects as transportation improvements are considered for inclusion in this plan and when these projects are prioritized for funding awards. Projects that demonstrate efforts to avoid, minimize or offset/compensate for environmental impacts to resources such as wetlands, forests and streams have been planned as part of the project receive a higher priority than those not having these considerations. Green infrastructure strategies exceeding minimum state compliance that are integrated into a project design also receive higher priority.
Trees and Stormwater
In 2017, OKI and its team of national partners launched an integrated tool and resource kit titled “Integrating Trees into Stormwater Management Design and Policy – A Guide for Local Decision Makers,” which is housed at treesandstormwater.org. The guide is organized to inform two distinct environmental types: developed and undeveloped environments. This structure enables the guide to be of practical use for every community in the OKI region, whether located in urban, suburban, or rural areas.
The guide includes a resource library with design templates for a wide variety of proven stormwater practices, based on an extensive literature review and stormwater engineer engagement during the guide development process. The guide will also provide practical information regarding long term maintenance of these green infrastructure solutions, and also on ordinances, policies, and ecosystem benefit analysis for local governments’ consideration.
In the OKI region and across the nation, the use of trees for managing stormwater has a long way to go to reach full potential. Research over the last decade has provided science and documented the value of trees as a viable stormwater management strategy. Trees and green cover have the ability to reduce the peak flow of stormwater runoff from urbanized areas and filter out pollutants and sediment before the runoff enters streams. While much work has been done to better understand the value of trees in stormwater management, few communities have embraced trees as a component of stormwater facility design and policy.
The impacts of flooding on all flood prone communities have the potential for being reduced when communities incorporate the practices recommended by the treesandstormwater.org guide. The incorporation of tree canopy, particularly in urban, deforested areas, provides many benefits to community residents. In addition to stormwater mitigation, these areas and the underserved residents will benefit from the economic, environmental, and human health benefits trees have proven to provide.
OKI receives national recognition
In October 2015, FHWA and the American Association of State Highway and Transportation Officials (AASHTO) recognized OKI for its vision and commitment to integrate these steps in its transportation planning activities as a leader and champion of the Eco-Logical approach.
In February 2018, OKI received recognition honoring its achievement as an early adopter Eco-Logical Implementation Assistance Program by the US Department of Transportation FHWA.