Corridors for Change

Exploring a multifunctional corridor concept for climate change mitigation, adaptation, and justice in Iowa

Carissa Shoemaker

March 31, 2021

I'm Carissa Shoemaker, a landscape architecture master's student at Iowa State University (ISU), graduating in May. This StoryMap is my creative component, a capstone project pieced together throughout my last year at ISU. The concept, Corridors for Change, was born from parallel interests in climate action and wildlife corridors, particularly those vast enough to accommodate large carnivores.

I recognized that while wildlife corridors are designed for a specific function, they are inherently multifunctional. In addition to facilitating dispersal and and providing habitat, for instance, these vegetated swaths build soil, infiltrate water, and sequester carbon. These services are sometimes listed in master plans as co-benefits, but are rarely designed for in the United States, nor are they leveraged to build cross-disciplinary teams, appeal to more diverse stakeholders, secure additional funding, or connect with local initiatives.

If corridors were billed as vital infrastructure, if they were valued for their ecosystem services and contributions to climate change mitigation and adaptation, perhaps they would be easier to implement. This is especially true of areas where the dominant catalysts for corridors—wildlife and recreation—aren't as salient. In Iowa, for example, a state physically and politically dominated by agriculture, anything that occupies otherwise productive land is a hard sell.

In fact, Iowa's ecosystem services are almost entirely relegated to its existing corridors: its rivers, roadsides, transmission lines, railroads, and field margins. If we highlighted that multifunctionality, even quantified it, maybe we could build a case for enhancing corridors across Iowa—rehabilitating, filling in gaps, and widening. Doing so would measurably improve the state's habitat and recreational amenities, of course, as well as its ecological and economic resilience. It would also establish a physical and procedural foundation and momentum for additional changes in landcover and management, whether in-field or in town.

Throughout this StoryMap, I provide some context for this investigation—definitions, theory, research, and precedents—and propose a multifunctional corridor scheme for Iowa. I then visualize and discuss the potential impact on Des Moines River Watershed landscapes and initiatives.

What are corridors?

It depends on who you ask. For the purposes of this story, the term is simply used to describe vegetated linear landscapes that, by their nature, benefit society and the environment.

Synonyms: buffers, greenways, greenbelts, parkways, and strips

Some corridors are planned to facilitate wildlife movement, accommodate recreation, or improve water quality.

Others are designed for another purpose or aren't designed at all, yet provide myriad co-benefits. These are called de facto corridors.

De facto corridors are easy to spot in Iowa, a state dominated by industrial agriculture. Stands of trees and patches of prairie are most often arranged around:

Rivers

Riparian corridors, floodplains

Linear Infrastructure

Railroads, roadways, trails, transmission corridors, pipelines

Farm Fields

Fencerows, windbreaks, ditches, edge-of-field conservation practices

When combined, these linear landscapes create a green network that:

Provides habitat, forage, and corridors for generalist species
Mitigates erosion and builds soil
Sequesters carbon and cycles nutrients
Infiltrates water, attenuates flooding, and intercepts sediment
Protects from wind and snow
Improves air quality
Beautifies the landscape
Increases land value
Creates economic opportunities
Enriches regional identity and sense of place
Bridges the urban-rural divide
Connects some of the state's most vulnerable communities with greenspace

What if we were to bolster Iowa's de facto corridors, starting with rivers?

Could this modest transformation pave the way for more resilient landscapes, economies, and communities?

01 / 14

Corridor theory and precedents

This idea—multifunctional corridors and large-scale planning—isn't new. It is not even new to landscape architecture. Landscape architects have actually been instrumental in corridor theory and application.

Olmsted: Parks & Parkways, 1860s

Many believe Fredrick Law Olmsted invented the greenway concept. He and his partner Vaux first introduced a tree-lined parkways in Central Park, separating foot traffic from carriage traffic. Olmsted built on this idea when he designed the Buffalo park system, proposing parks be connected by parkways (pictured right).

Olmsted also designed corridors for ecological function, best exemplified in his plan for Boston's Emerald Necklace park system.

*Olmsted's Emerald Necklace park system, established in Boston in the 1860s. Image from https://www.emeraldnecklace.org/wp-content/uploads/2015/11/Emerald-Necklace-Map.pdf*

Howard: Garden City, 1898

Ebenezer Howard imagined garden cities surrounded by “country belts,” a mix of open space and clustered agriculture and industry. Thus, Howard's green belts were inherently multifunctional, encompassing transportation, natural landscapes, agricultural systems, and economic uses, and restricting urban development.

Howard's book, A Peaceful Path to Real Reform (later reissued as Garden Cities of To-morrow), heavily influenced the burgeoning urban planning field, and several garden cities were actually built around the world.

*Diagram of garden cities in their regional context. Image from https://en.wikipedia.org/wiki/Garden_city_movement#/media/File:Diagram_No.7_(Howard,_Ebenezer,_To-morrow.).jpg*

*An imagined garden city. Image from reddit.com/r/RetroFuturism/comments/fk7vhe/the_garden_cities_of_tomorrow_by_sir_ebenezer/*

Forman & Godron: Landscape Ecology, 1986

Richard Forman & Michel Godron’s foundational work developed structural connectivity theory, defining and diagramming the main components as patches, corridors, and the matrix (the surrounding area with a different composition and function). In addition, they explored the topics of landscape configuration, landscape modification gradient, landscape resistance, and network connectivity. Forman further developed these concepts in a subsequent book, Land Mosaics: The ecology of landscapes and regions (1995).

*Structural connectivity diagrammed around Estherville, Iowa. Corridors connect patches, forming a network within the surrounding matrices of agricultural and urban/residential land*

*Forman identified and diagrammed land-based patterns in his exposition on landscape composition,* Land Mosaics. *He observed that land uses can sometimes more seamlessly blend, forming gradients, but more often form aggregates*

Little: Greenways for America, 1990

Charles Little advocated for five major types of greenways in his book, Greenways for America:

Urban riverside, often to revitalize run-down waterfronts
Recreational with paths, often long-distance and built on canals, railways, and other rights-of-way
Ecologically significant natural corridors, like rivers and ridgelines
Scenic and historic routes—roads, highways, waterways
Comprehensive greenway systems or networks, usually based on natural landforms such as valleys and ridges

Little was not the first to propose recreational greenways, but he saw how they could be implemented in a variety of settings, and how widespread adoption could change America's landscape and culture.

Lewis: Tomorrow by Design, 1996

Philip Lewis proposed a regional landscape planning theory with higher density areas contained by corridor networks protecting environmentally sensitive areas, such as waterways, wetlands, and steep slopes. Lewis' process was rooted in identifying and analyzing physical patterns, much like Forman & Godron's, although he was driven by function, namely environmentally-conscious regional planning.

*Lewis identified population centers from nighttime satellite imagery*

*Development links together to form "constellations"*

*Key resources around which development should be planned*

Bentrup: Conservation Buffers, 2006

In this guide, Bentrup offers 80 design concepts, with specifications and illustrations, informed by over 1,400 research publications. Bentrup organizes guidelines into seven categories: water quality, biodiversity, productive soils, economic opportunities, protection and safety, aesthetics and visual, and outdoor recreation. Bentrup incorporates working landscapes into each, and even diagrams several ideas for working buffers, including carbon sequestration, multi-story cropping, windbreaks, alley cropping, and biofuels.

*An example of guidelines and diagrams from the Water Quality section*

*Figures and recommendations from the Biodiversity section*

*An agroforestry concept from the Economic Opportunities section*

Hilty et al.: Corridor Ecology, 2019

Hilty and colleagues published the first edition of Corridor Ecology in 2006, explaining corridor science and history, typology, and planning considerations. In this edition, they updated references and theory where needed, more thoroughly considered climate-wise connectivity, and broadened their scope to include marine environments.

IUCN: Guidelines, 2020

Just last year, a team of scientists produced international guidelines for ecological corridors and networks. As with Hilty et al.’s Corridor Ecology book, they cover the scientific basis for connectivity, terminology, and planning principles. The IUCN team also delves into law and policy, as well as a number of case studies.

Contemporary precedents

The following five precedents reflect the spirit of my capstone concept. Most grew from de facto corridors—drover’s roads, rivers, and transmission corridors—are deliberately multifunctional, and incorporate working landscapes. Each fosters economic benefits, whether by preventing costly flooding or supporting regional livestock grazing and products.

I originally assumed local precedents would be more culturally and politically appropriate, but it turns out that most contemporary projects in the United States are designed either for wildlife—like the awe-inspiring Yellowstone to Yukon Conservation Initiative —or for recreation. Even the East Coast Greenway Alliance’s Greenway Stimulus scheme, which advocates for corridors’ economic potential (jobs creation, health, and equitable access), doesn't quite fit. The economic benefits are still secondary to active transportation in the East Coast Greenway network.

In the end, I chose three precedents from Europe, one from the United States, and one from Canada. Continue scrolling to learn about each project.

Vías Pecuarias

Where: Spain.
When: date back to 654 AD, began to garner public protections in 1995.
What: network of livestock routes through open or wooded pastures. Nearly 80,000 miles in length, around 1 million acres linking protected, unprotected, and urban lands.
Why: enhance biodiversity through intensive grazing and landscape conservation. Fertilize, build soil, and distribute seeds through dung, facilitating range shifts as the climate changes. Combats economic and climate crises.
How: state protections and groups advocating for their rehabilitation, as well as transhumance—moving livestock from one grazing ground to another seasonally.
Who: public-private partnerships—individuals, governmental agencies, associations, universities, nonprofits, working groups.

*Images of drover’s roads, courtesy of conservationcorridor.org*

*Transhumance, high intensity grazing. Image from pastos.es*

Room for the River

Where: Amsterdam, Netherlands.
When: program started in 2007, initial stage (over 30 projects) completed by 2018.
What: the Dutch government launched a program to widen watercourses, to make room for the river to flood without wreaking havoc.
Why: the country had experienced extreme flooding in the 1990s and felt it needed to act, especially as climate change is projected to bring more, and more intense, storms. The plan also presented a chance to improve aesthetics and recreation opportunities.
How: floodplains were reclaimed, with 50 houses demolished and dikes moved further inland, and reshaped to accommodate and retain floodwater. See the graphic below for a full list of strategies.

Ribeira das Jardas

Where: Lisbon, Portugal; Ribeira das Jardas (aka Ribeira de Barcarena).
When: began in 2008
What: an urban river was rehabilitated to improve ecological function and residents’ quality of life.
Why: rapid development in the absence of environmental planning had left the river degraded, polluted with sewage and runoff, and confined to a concrete channel. These alterations had amplified flooding, which was intensifying with climate change. Finally, Lisbon’s rivers are some of the only remaining habitat, given the area’s population density, placing even more value on their restoration.
How: the sewage system was first upgraded, then buildings were demolished in key areas to make room for the floodplain, banks were modified, and vegetation was restored. Gathering places and trails were also established.
Who: this project was driven by landscape architects, in partnership with public and private groups.

*An upper portion of the river in 2010—note concrete channel and minimal vegetation*

*By 2020, the bank had been transformed, vegetation planted, and terraces altered*

*Further south, 2009, the river was trapped between two high flood walls*

*By 2019, the channel was enriched with vegetation, although the flood walls had to stay*

Florida Wildlife Corridor

Where: Florida, USA.
When: in a nutshell, the concept originated in the 1980s, but the corridor was first mapped in 2010.
What: a statewide ecological corridor totaling 16.7 million acres—9.8 million acres of protected lands and 6.9 million acres of opportunity lands (including 1.26 million acres of ranch land, 2.28 million acres of silviculture).
Why: to protect biodiversity, essential ecosystem services, and rural, natural, and cultural heritage.
How: GIS mapping of protected lands and critical linkages to form a functional corridor, as well as focal areas for future protection, bottlenecks, highway crossings, recreation amenities, and more. These maps are then used to raise public awareness and support, as well as identify land for purchase through the Florida Forever program, either as full fee acquisitions or conservation easements.
Who: Florida Wildlife Corridor is the organizing nonprofit, originally the Legacy Institute for Nature and Culture (LINC). The project has numerous partners (some co-founders) across sectors, too, including Florida chapters of The Nature Conservancy, Audubon Society, DNR, Defenders of Wildlife, and local groups, like 1000 Friends of Florida.

*Ranch and silvicultural land provide functional connectivity and habitat for some species, alongside protected lands*

*Focal areas are deemed high priority for acquisition and/or protection, due to their spatial configuration and proximity to development*

The land highlighted represents the missing puzzle pieces of a statewide ecological network that provides functional connectivity for wide-ranging species, like the Florida panther and Florida black bear

The Meadoway

Where: Toronto, Ontario, Canada. When: program began in 2012, The Meadoway was launched 2018.
What: a Toronto initiative to transform a 10-mile electricity transmission corridor into a space for public good, with a multi-use trail network, gathering areas, and restored meadows and wetlands.
Why: the transmission corridor was formerly turf grass, wasted space extending from the heart of the city into the countryside. It presented a chance to connect waterways, parks, trails, neighborhoods, and habitat, and to create a blueprint for future projects around powerlines.
How: the city partnered with the power company, found support for the project, and engaged design teams to draw up plans and visualizations, with community input.

Who: the Toronto and Region Conservation Authority (TRCA), City of Toronto, W. Garfield Weston Foundation, the power company, Perkins & Will, Future Landscapes, etc.

*A visualization from the planned Meadoway, featuring urban agriculture*

*A transmission corridor of turf grass becomes a diverse meadow and recreational network*

Why not plan wildlife corridors in Iowa?

01 / 05

Minimal habitat

Iowa is often cited as the most ecologically altered state in the nation. Thus, there aren't currently many patches for wildlife corridors to connect.

Ill-fitting solution

This isn't to say Iowa's wildlife is thriving. There are imperiled species that could use more habitat, it's just that corridors are better conduits than habitats.

Low connectivity potential

Low ecological integrity results in a low connectivity potential. Essentially, there are few incentives and many barriers to wildlife corridor planning in Iowa.

High resistance

Iowa's urban development, infrastructure, and farms create high resistance to wildlife dispersal and corridor implementation.

Alternatives

There is hope, however. This Iowa DNR Wildlife Action Plan figure demonstrates that there are zones where organizational priorities overlap, creating opportunity for cooperative conservation actions. Even if wildlife corridors aren't feasible now, other conservation actions can be implemented, and may even pave the way for future wildlife corridors.

Envisioning a multifunctional corridor scheme in the Des Moines River Watershed

While the Missouri River and Mississippi River are recognized as having a greater wildlife corridor potential, the Des Moines River is a promising candidate for a multifunctional corridor scheme. Its watershed spans the state, has robust de facto corridors, hosts diverse local and regional initiatives, and is primed for cooperative conservation action, by the Iowa DNR's metric.

In the following map tour, I explore this potential, charting a course through twelve significant places within the watershed. I have placed variable buffers around de facto corridors and highlighted the 500 year floodplain to indicate potential corridor improvements. Click through the tour or scroll around the map to investigate the opportunities and challenges of such a scheme, in relation to existing landscape uses and conservation practices.

Des Moines River Enters Iowa

Corridors to Networks

Connecting Parks

Oxbow Restoration in the Boone River Watershed

Saylorville Lake

Upper Fourmile Creek

Lower Fourmile Creek Greenway

Downtown Des Moines

Yeader Creek

Lake Red Rock Floodplain

Environmental Justice

Des Moines River Joins the Mississippi

Des Moines River Enters Iowa

The Des Moines River's headwaters are in Minnesota. Before the river even gets to Iowa, it passes through a 983,719 acre basin, pictured above. (This does not include the East Fork Des Moines River Watershed , which feeds in from the northeast.) It may be valuable to compare and share best management practices (BMPs) across borders.

Minnesota, for instance, recently instituted a Buffer Law requiring perennial vegetative buffers of up to 50ft along rivers, streams, and lakes. The deadline for implementation was November 2017, and as of July 2019, approximately 98% of parcels statewide are compliant. Moreover, the Minnesota Pollution Control Agency mandates Water Restoration and Protection Strategies and maps BMPs by watershed.

Any attempt at Des Moines River Watershed-level planning should involve stakeholders along the entire watershed, including those north of the border. Both states would surely benefit from such a partnership, and collaborating along watershed rather than state lines would allow for more holistic, grounded solutions.

Corridors to Networks

Here, different de facto corridors—riparian, railway, highway, and transmission—coalesce to form a green network. As corridor density increases, it grows easier to identify pinch points where linkages could be formed, facilitating wildlife movement and increasing local ecosystem services.

This snapshot also inspires questions about how proposed corridors would be received by farmers, businesses, and residents, and what the costs and benefits would be for each group. What would win farmer buy-in in the face of reduced yields? Could the corridor's composition correspond to local businesses (e.g., vegetative screens intercepting concentrated animal feeding operation (CAFO) particulates)?

Finally, the intersection of diverse infrastructure and land uses highlights potential cross-sector partnerships. Perhaps the Iowa DOT could work with the rail and power companies that own the corridors adjacent to Highway 4 to implement integrated roadside vegetation management (IRVM) spanning all three corridors. Perhaps farmers along the corridor could be incentivized to grow perennial crops for biomass—amassed at a local co-op to be processed at the biorefinery in Superior —or to hay for local livestock.

A multifunctional corridor plan would go beyond a land-based network to form social and economic partnerships, improving Iowa's resilience to a multitude of disturbances.

Connecting Parks

As discussed earlier, most of Iowa's habitat follows the rivers. It follows, then, that most of Iowa's recreational parks and protected lands do, too. Wildlife dwelling in these patches would benefit from riparian corridor improvements because they would 1) increase habitat connectivity, facilitating migration, dispersal, and gene flow, and 2) provide additional opportunities for forage and cover (supporting increased populations and biodiversity).

In addition to benefiting wildlife, bolstered corridors would enrich existing park systems and trail networks, including water trails . They could even pave the way for new regional trails, building on the momentum of the Iowa Parks Foundation's Parks to People framework and the Iowa DOT's Statewide Network Recommendations , some of which are pictured above, Chapter 5 of the 2018 Bicycle and Pedestrian Long-Range Plan .

Oxbow Restoration in the Boone River Watershed

Just as the Des Moines River Watershed feeds into the Mississippi River, sub-watersheds feed into the Des Moines River. One of these is the Boone River Watershed, the site of an incredible, collaborative effort to restore oxbows , led by Karen Wilke with The Nature Conservancy .

Oxbows are old river meanders that have been cut off from present-day water flow. Normally, they would continue to function as wetlands, providing forage and habitat for wildlife (including the endangered Topeka shiner), intercepting and removing nutrients from runoff, and increasing flood storage. In our agricultural landscapes, however, they tend to fill with sediment, nullifying their services.

Through the Boone River Project, 28 oxbows have been restored and over 160 have been identified for restoration. Whether through floodplains or a general riparian buffer, many of these oxbows may be encompassed by the proposed corridor scheme. Their inclusion in a Des Moines River Watershed—or even statewide—scale plan could garner the Boone River Project even more prominence and support. Further, the oxbow restoration project could be replicated across the greater watershed.

Saylorville Lake

Saylorville Lake and surrounding lands serve to reduce flood risk, safeguard water supply, manage drought, accommodate fish and wildlife, and provide recreation opportunities. It is collectively managed by the Iowa DNR , county conservation offices , the Army Corps of Engineers , and others—see image above from the US Army Corps of Engineers' Saylorville Lake Master Plan, 2015 .

The lake normally covers 5,950 acres, and can reach 16,700 acres at full flood stage, growing from 17 miles to 54 miles long. The Saylorville Lake Project as a whole constitutes 26,000 acres. That represents 3.6% of Iowa's protected lands, given that 2% of Iowa's 36 million acres is permanently protected, amounting to 720,000 acres. Some of the land at the northern edge of the lake has been designated as the Ding Darling Greenway, and all of the land feeds into the Des Moines River Recreational Greenbelt , which stretches from Fort Dodge to Pella.

Even though the Saylorville complex is one of the greenest spots in Iowa, it could still benefit from additional buffering. Additional protections upstream and uphill would serve to improve water quality (nutrients and sedimentation), hydraulics, drought tolerance, and flood risk mitigation. This is one of the key spaces where green infrastructure can pair with gray to create more resistant and resilient systems.

Upper Fourmile Creek

Fourmile Creek is a tributary of the Des Moines River, and an excellent case study for watershed management and greenway planning and implementation. The Fourmile Creek Watershed begins just northwest of Sheldahl. Fourmile Creek runs from there through Ankeny, East Des Moines, and the western edge of Pleasant Hill, then joins the Des Moines River near Highway 65. Because the creek spans rural, suburban, and urban land uses, as well as several different jurisdictions, it is an excellent case study for complex, watershed-level planning.

The Fourmile Creek Watershed encompasses 76,600 acres—60% of which is agricultural—and nine communities, and bridges three different counties. In 2014, a Fourmile Creek Watershed Management Plan was devised, coordinated by the Fourmile Creek Watershed Management Authority (FCWMA). The plan addresses watershed characteristics, pollutants, stream assessment, stakeholder involvement, implementation, prioritization, and budget/funding.

Goals and approaches vary throughout the creek's upper, middle, and lower sections. Water quality is the main focus of upper Fourmile Creek Watershed, given the preponderance of agriculture. Some in-field practices being promoted include cover crops, reduced tillage, nutrient management, conservation crop rotation, prescribed grazing, terraces, and conservation cover. Linear interventions in-field and edge-of-field include grassed waterways, contour buffer strips, filter strips, water and sediment control basins (WASCOBS), bioreactors, wind breaks, and saturated buffers.

John Swanson, Polk County Watershed Management Authority Coordinator, has been pursuing saturated buffers in the upper Fourmile Creek Watershed. Instead of outletting tile lines into Fourmile, fields with saturated buffers outlet onto a vegetated filter strip, allowing for infiltration and interception of nutrients. At least forty saturated buffers are set to be installed in the upper watershed this year, at almost no cost to participating landowners.

Swanson's saturated buffer campaign and the in-field practices recommended throughout the Fourmile Creek Watershed emphasize the importance of holistic strategies for watershed reparation. Regreening alone won't do the trick, we also need to rework how we manage our land and water. As with the Boone River Watershed oxbow project, the Fourmile Creek Watershed approach offers a model for replication throughout the greater watershed.

Lower Fourmile Creek Greenway

Lower Fourmile Creek, in turn, may provide a model for urban waterways. Lower Fourmile is currently being transformed into a greenway . While some of the habitat highlighted in the plan above is remnant, some is being reconstructed, following buyouts in the 500 year floodplain. While buyouts can be contentious, disrupting lives and communities, flooding is only becoming more frequent and extreme, due to climate change. If cities have the capital for buyouts, it seems prudent to evacuate the 500 year floodplain now rather than later.

The first Greenway Master Plan was drafted in 2010, followed by the formation of the Fourmile Creek Watershed Management Authority in 2012, the Fourmile Creek Watershed Study from 2011 to 2013, and the Fourmile Creek Watershed Management Plan in 2015. The most recent Greenway Master Plan , prepared by Snyder & Associates, represents the first step toward implementing the vision outlined in previous plans. Its primary role is to identify critical greenway components and potential recreational and educational amenities.

Much of the restoration work, pictured above, began in 2020, with a projected 5-7 year timeline. The greenway is truly multifunctional, improving flood management, water quality, connectivity and access, educational opportunities, habitat, and economic resiliency.

Downtown Des Moines

Downtown Des Moines is a different story. While reconnecting the river to its floodplain is the ideal—giving the river room to rise and fall, as in the Amsterdam and Lisbon precedents—in this case, it would require extensive demolition and careful reengineering. Des Moines is unlikely to undertake such a feat, especially as new developments continue to spring up around the water's edge.

However, a Greater Des Moines Water Trails and Greenways Plan was adopted in 2016, proposing environmental, recreational, and economic improvements along more than 150 miles of waterways. The plan was primarily composed by the Des Moines Area Metropolitan Planning Organization (DMAMPO) and the Iowa DNR, and plugs into the Central Iowa Water Trails initiative.

Recommendations for downtown Des Moines , informed by community and stakeholder input, include activating the Des Moines River through dam mitigation and shoreline improvements, as pictured above. This would allow residents and visitors to physically connect with the river, and would restore some of its ecological function. Moreover, the river's 100 year floodplain is meant to be developed into a greenway, accommodating trails, connecting parks and historic/cultural nodes, providing habitat, and more.

If this Vision for the Des Moines River weren't already in motion, I would hesitate to include the downtown district in a climate corridor proposal; it would be tremendously difficult to gain traction from the outside-in. With the plan in place, its components and findings could be incorporated into a greater scheme. Or, with the support of a greater network of collaborators and funding streams, the Vision could even be expanded upon.

Yeader Creek

Yeader Creek is another sort of urban stream, they type that was too often filled in and paved over during urbanization. It's small enough that it doesn't pose much of a flood threat, so wouldn't warrant buyouts. Yet, it does impact adjoining yards, suffers from illegal dumping and urban runoff, and provides some ecological services. Reinforcing Yeader Creek's riparian corridor could improve those ecological services and heighten visibility and monitoring, thereby reducing dumping.

One option for rehabilitation—submitted by Jenny Richmond, Assistant Director for the Des Moines' Parks and Recreation—is an urban incentive program for conservation practices and/or an easement program, defining and providing management for a wider stream buffer. Neither option would decrease the city's tax base (which is a common argument against new parks and conservation projects), and both could provide economic support for residents along Yeader Creek.

Lake Red Rock Floodplain

While Saylorville Lake is large at nearly 6,000 acres of water, Lake Red Rock has 15,250 acres of water. In fact, Red Rock has the largest contiguous public land base in the state, approximately 38,000 acres in total. That constitutes 5.3% of Iowa's protected lands.

Until 2015, Lake Red Rock was operating on a master plan from 1976, providing guidelines for natural resource management and recreation development. Red Rock's new Master Plan offers updated recommendations and GIS inventories and analyses. One map of particular significance to the proposed multifunctional buffer is Environmentally Sensitive Areas (ESAs), shown above.

While the ESAs pictured abruptly stop at Red Rock's boundary, it is likely their true borders extend into private lands, and that a more robust corridor of protected lands would offer greater protections. Even as shown on the map, the ESAs would benefit from an uphill buffer, as they are currently subjected to runoff from surrounding fields, and the nutrients, chemical, and sediment that come with it.

In addition to ESAs, reclaiming floodplains around Lake Red Rock would help mitigate the destructive force of its seasonal, extensive floods. It would also support the Master Plan's goals of increased connection and reduced fragmentation, habitat enhancement, additional land for trails, fisheries improvement, and the maintenance or addition of public hunting lands.

Environmental Justice

Multifunctional corridors based around de facto corridors would theoretically contribute to environmental justice in rural and urban areas. Rural communities are generally vulnerable, and many marginalized urban communities are forced into unpleasant and high risk areas—floodplains, railroads, roadsides. Regreening around de facto corridors could provide vulnerable communities greater access to nature and recreation amenities, a buffer from air and water pollution, economic opportunities, and a source of pride and sense of place.

Later, as the corridor network inspired land use change further afield, source water quality could improve. This could help rectify a current injustice in Ottumwa . The Des Moines River is the city's only source of drinking water. By the time it reaches them, however, it has absorbed runoff and associated contaminates from tens of thousands of acres of farmland. In the last five years, the Des Moines River has exceeded the EPA's drinking water standard for nitrates, 10mg/L. While cities like Des Moines have the resource to remove these nitrates, Ottumwa does not.

Moreover, Ottumwa is one of Iowa's poorest cities, in one of Iowa's poorest counties. It is also one of Iowa's most diverse municipalities, relative to its size. Low household income and racial minority status are defined social vulnerabilities that, particularly when layered atop other vulnerabilities, dampen individual and community resilience to environmental hazards, such as nitrate-laden drinking water. The maps above depict how social vulnerabilities and environmental hazards can layer to form conditions for environmental injustices. In this case, low income and racial minority status are combined on the left, and exposure to respiratory hazards is shown on the right.

The Des Moines Water Works filed a now infamous case in 2015 against three disproportionately bad polluters: Sac, Calhoun, and Buena Vista Counties. The organization argued that producers should be held accountable for pollution, otherwise it will continue to go unregulated, with deleterious effects. The suit built upon the Environmental Working Group's " Fooling Ourselves " educational campaign and initiative advocating for regulations. Proponents asserted that voluntary conservation practices can be discontinued at any time, leaving our environment and communities perpetually vulnerable.

Des Moines River Joins the Mississippi

Finally, the Des Moines River flows into the Mississippi River. This confluence serves as a reminder of how the two rivers are connected, how everything that happens in the Des Moines River Watershed impacts the Mississippi River. This puts additional weight on conservation strategies employed—no one wants to contribute to the Dead Zone in the Gulf of Mexico—and it also highlights how initiatives in the Des Moines River Watershed can plug into Mississippi River Basin initiatives.

There's the Mississippi River Basin Healthy Watersheds Initiative , for instance, encouraging voluntary conservation efforts over 12 states. An Eagle Grove, IA, producer was actually just celebrated on the initiative website for his measurable reduction in nitrates, due to his implementation of cover crops, strip-till, and fertilizer reduction. Linking to existing projects and collectives can lend local efforts legitimacy, connect them with resources, reduce barriers to implementation, and amplify their effects.

Conclusion

The corridors mapped above produce more questions than answers. Are the proposed corridor widths feasible, or even ideal? How many acres would this scheme engage? What would be gained and lost? Would corridor programs be regulatory—mandated by federal legislation or local law—or voluntary, building on Iowa’s conservation incentive programs? That was the goal, though. Overlaying complex corridors on the Des Moines River Watershed helps us to identify potential variables, stakeholders, and collaborators, and to visualize land use change at a variety of scales, from individual parcels to the greater watershed.

As for next steps, I had initially sought to calculate the impact of such a plan on Iowa’s natural resources, climate change mitigation and adaptation, marginalized communities, and economy. If there were a quantifiable impact, a case could be made for multifunctional corridors’ inclusion in federal infrastructure, climate change, and stimulus plans. I then wanted to explore how pro-climate practices could radiate from corridors, transforming vulnerable landscapes, farming practices, and land management.

Corridor widths could be adjusted in relation to additional variables, such as stream designation (meandered, protected, impaired, source water). A larger network could then be imagined, with additional linkages formed at pinch points and pro-climate practices radiating from corridors into agricultural fields and onto steep slopes, shown in yellow

However, if I were to pilot any program today, I would put the corridor concept on the back burner in favor of coalition-building across the Des Moines River Watershed. There are already incredible initiatives and individuals within the watershed that would benefit from additional support and exposure, both of which I believe a greater watershed collaborative would provide. As part of a larger network and planning process, these programs could even be replicated in basins throughout the greater watershed.

Already, those I consulted for my capstone span sectors, disciplines, and perspectives. A Des Moines River Watershed coalition could grow from this core group to their supporters and collaborators, and beyond

Moreover, a Des Moines River Watershed plan could begin to address some of the bigger issues that brought me to corridors, namely climate change and justice. Watersheds naturally cross jurisdictional and disciplinary boundaries, as is demonstrated by efforts in the Four Mile Creek and Boone River Watersheds, discussed above. They require and provide a framework for diverse teams and funding streams, and actions within them are sure to be relevant to all residents; the same cannot be said of counties. Smaller municipalities and organizations may not have the capacity or desire to conduct local research, study projections, or draft action plans, while a greater watershed coalition would.

Finally, a Des Moines River Watershed plan could more readily be plugged into, and shaped by, an Upper Mississippi River Basin plan than local initiatives. More than providing a platform for statewide collaboration, a Des Moines River Watershed plan could pave the way for regional action.

Sources

Angel, J., Swanston, C., Boustead, B. M., Conlon, K. C., Hall, K. R., Jorns, J. L. Kunkel, K. E. Lemos, M. C., Lofgren, B., Ontl, T. A., Posey, J., Stone, K., Takle, G., and Todey, D. (2018). Midwest. In D.R. Reidmiller, C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (Eds.), Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II (pp. 872-940). U.S. Global Change Research Program, Washington DC: USA.

Askins, R. A., Folsom-O'Keefe, C. M., & Hardy, M. C. (2012). Effects of vegetation, corridor width and regional land use on early successional birds on powerline corridors. Plos one, 7(2), e31520.

Ban, N. C., Mills, M., Tam, J., Hicks, C. C., Klain, S., Stoeckl, N., Bottrill, M.C., Levine, J., Pressey, R.L., Satterfield, T., & Chan, K. M. (2013). A social–ecological approach to conservation planning: embedding social considerations. Frontiers in Ecology and the Environment, 11(4), 194-202.

Beier, P. (2012). Conceptualizing and designing corridors for climate change. Ecological Restoration, 30(4), 312-319.

Bennett, Andrew F, Radford, James Q, & Haslem, Angie. (2006). Properties of land mosaics: Implications for nature conservation in agricultural environments. Biological Conservation, 133(2), 250-264.

Bentrup, G. (2008). Conservation Buffers—Design guidelines for buffers, corridors, and greenways. Gen. Tech. Rep. SRS–109. Asheville, NC: US Department of Agriculture, Forest Service, Southern Research Station. 110, 109.

Bentrup, G., & Leininger, T. (2002). Agroforestry: mapping the way with GIS. Journal of Soil and Water Conservation, 57(6), 148A-153A.

The Biden Plan to Build a Modern, Sustainable Infrastructure and an Equitable Clean Energy Future. (2021). Joe Biden. Retrieved March 27, 2021, from https://joebiden.com/clean-energy/

Carroll, C., Parks, S. A., Dobrowski, S. Z., & Roberts, D. R. (2018). Climatic, topographic, and anthropogenic factors determine connectivity between current and future climate analogs in North America. Global Change Biology, 24(11), 5318-5331.

Des Moines Area Metropolitan Planning Organization (DMAMPO). (2016). Water Trails and Greenways Master Plan. DMAMPO. https://dmampo.org/water-trails/

Des Moines Area Metropolitan Planning Organization (DMAMPO) & Iowa Department of Natural Resources (Iowa DNR). (2016). A Vision for Des Moines River: Booklet 3 of 8, Greater Des Moines Water Trails and Greenways. DMAMPO. https://dmampo.org/wp-content/uploads/2016/10/3-dsm-river.pdf

Dosskey, M., Wells, G., Bentrup, G., & Wallace, D. (2012). Enhancing ecosystem services: designing for multifunctionality. Journal of Soil and Water Conservation, 67(2), 37A-41A.

Enloe, S. K., Schulte, L. A., & Tyndall, J. C. (2014). Toward a collaborative approach to watershed management: Lessons learned from the Boone River Watershed, Iowa. Journal of Soil and Water Conservation, 69(5), 149A-153A.

Fleming, B., Weller, R., Lillehei, X., Hammaker, Z., Li, X., Wang, Q., Jabs, N., Zhang, A., Darling, A., & Creager, R. (2019). The 2100 Project: an Atlas for the Green New Deal. The McHarg Center. https://mcharg.upenn.edu/2100-project-atlas-green-new-deal

Forman, Richard T. T. (1995). Land mosaics : The ecology of landscapes and regions. Cambridge; New York: Cambridge University Press.

Forman, Richard T. T, & Godron, Michel. (1986). Landscape ecology. New York: Wiley.

Fremier, A. K., Kiparsky, M., Gmur, S., Aycrigg, J., Craig, R. K., Svancara, L. K., Goble, D.D., Cosens, B., Davis, F.W., & Scott, J. M. (2015). A riparian conservation network for ecological resilience. Biological Conservation, 191, 29-37.

Hess, George R, & Fischer, Richard A. (2001). Communicating clearly about conservation corridors. Landscape and Urban Planning, 55(3), 195-208.

Hilty, J., Worboys, G. L., Keeley, A., Woodley, S., Lausche, B. J., Locke, H., Carr, M., Pulsford, I., Pittock, J., White, J.W., & Theobald, D. M. (2020). Guidelines for conserving connectivity through ecological networks and corridors. IUCN, International Union for Conservation of Nature.

Hilty, J. A., Keeley, A. T., Merenlender, A. M., & Lidicker Jr, W. Z. (2019). Corridor ecology: linking landscapes for biodiversity conservation and climate adaptation. Island Press.

Iowa Department of Natural Resources (Iowa DNR). (2015). Iowa Wildlife Action Plan: Securing a future for fish and wildlife—A conservation legacy for Iowans. Iowa DNR. https://www.iowadnr.gov/Conservation/Wildlife-Stewardship/Iowa-Wildlife-Action-Plan

Iowa Department of Natural Resources (Iowa DNR). (n.d.) Iowa Habitat and Access Program (IHAP). https://www.iowadnr.gov/Hunting/Places-to-Hunt-Shoot/Habitat-Access-Program

Iowa Department of Transportation (Iowa DOT). (2018). Statewide Network Recommendations: Iowa Bicycle and Pedestrian Long Range Plan. https://iowadot.gov/iowainmotion/files/bike-ped-plan-chapter5.pdf

Iowa Parks Foundation. (2014). Parks to People: Exceptional places and experiences in everyday lives; A 21st Century Park System Strategic Plan for Iowa. The Iowa Legislature. https://www.legis.iowa.gov/docs/publications/SD/24747.pdf

Keeley, A. T., Ackerly, D. D., Cameron, D. R., Heller, N. E., Huber, P. R., Schloss, C. A., Thorne, J.H., & Merenlender, A. M. (2018). New concepts, models, and assessments of climate-wise connectivity. Environmental Research Letters, 13(7), 073002.

Keeley, A. T., Basson, G., Cameron, D. R., Heller, N. E., Huber, P. R., Schloss, C. A., Thorne, J.H., & Merenlender, A. M. (2018). Making habitat connectivity a reality. Conservation Biology, 32(6), 1221-1232.

Klein, N. (2020). On fire: the (burning) case for a green new deal. Simon & Schuster.

Kremen, C., & Merenlender, A. M. (2018). Landscapes that work for biodiversity and people. Science, 362(6412).

Law, P. R., & Fuller, M. (2018). Evaluating anthropogenic landscape alterations as wildlife hazards, with wind farms as an example. Ecological Indicators, 94, 380-385.

Lewis, P. (1996). Tomorrow by design: A regional design process for sustainability. (Wiley series in sustainable design). New York: J. Wiley.

Little, C. (1990). Greenways for America. Baltimore: Johns Hopkins University Press.

McGuire, J. L., Lawler, J. J., McRae, B. H., Nuñez, T. A., & Theobald, D. M. (2016). Achieving climate connectivity in a fragmented landscape. Proceedings of the National Academy of Sciences, 113(26), 7195-7200.

McHarg, I. L. (1969). Design with nature. New York: American Museum of Natural History.

Nassauer, J. I., Dowdell, J. A., Wang, Z., McKahn, D., Chilcott, B., Kling, C. L., & Secchi, S. (2011). Iowa farmers' responses to transformative scenarios for Corn Belt agriculture. Journal of soil and water conservation, 66(1), 18A-24A.

Ontl, T. A., Janowiak, M. K., Swanston, C. W., Daley, J., Handler, S., Cornett, M., Hagenbuch, S., Handrick, C., McCarthy, L., & Patch, N. (2020). Forest management for carbon sequestration and climate adaptation. Journal of Forestry, 118(1), 86-101.

Recognizing the duty of the Federal Government to create a Green New Deal, H. Res. 109, 116th Cong. (2019). https://www.congress.gov/116/bills/hres109/BILLS-116hres109ih.pdf

Reid, W. V., Mooney, H. A., Cropper, A., Capistrano, D., Carpenter, S. R., Copra, K., Dasgupta, P. … Zurek, M. B. (2005). Ecosystems and Human Well-Being: Synthesis. A Report of the Millennium Ecosystem Assessment, Washington DC.

Rudnick, D., Ryan, S. J., Beier, P., Cushman, S. A., Dieffenbach, F., Epps, C., Gerber, L.R., Hartter, J.N., Jenness, J.S., Kintsch, J., & Merenlender, A. M. (2012). The role of landscape connectivity in planning and implementing conservation and restoration priorities. Issues in Ecology.

Ryan, R. L. (1998). Local perceptions and values for a midwestern river corridor. Landscape and urban planning, 42(2-4), 225-237.

Samways, M. J., Bazelet, C. S., & Pryke, J. S. (2010). Provision of ecosystem services by large scale corridors and ecological networks. Biodiversity and Conservation, 19(10), 2949-2962.

Schoeneberger, M. M., Bentrup, G., & Francis, C. A. (2001). Ecobelts: reconnecting agriculture and communities. Interactions between agroecosystems and rural human communities. Adv. in Agroecology. CRC Press, Boca Raton, FL, 239-260.

Schoeneberger, M. M., Bentrup, G., & Patel-Weynand, T. (2017). Agroforestry: enhancing resiliency in US agricultural landscapes under changing conditions. Gen. Tech. Report WO-96. Washington, DC: US Department of Agriculture, Forest Service, 96.

Thogmartin, W. E., López-Hoffman, L., Rohweder, J., Diffendorfer, J., Drum, R., Semmens, D., Black, S., Caldwell, I., Cotter, D., Drobney, P., & Jackson, L. L. (2017). Restoring monarch butterfly habitat in the Midwestern US: ‘all hands on deck.’ Environmental Research Letters, 12(7), 074005.

Van Der Windt, H. J., & Swart, J. A. A. (2008). Ecological corridors, connecting science and politics: the case of the Green River in the Netherlands. Journal of Applied Ecology, 45(1), 124-132.

Villemey, A., Jeusset, A., Vargac, M., Bertheau, Y., Coulon, A., Touroult, J., Vanpeene, S., Castagneyrol, B., Jactel, H., Witté, I., & Deniaud, N. (2018). Can linear transportation infrastructure verges constitute a habitat and/or a corridor for insects in temperate landscapes? A systematic review. Environmental Evidence, 7(1), 5.

Wildlife Corridors Conservation Act of 2019, S. 1499, 116th Cong. (2019). https://www.congress.gov/bill/116th-congress/senate-bill/1499/text

Wojcik, V. A., & Buchmann, S. (2012). Pollinator conservation and management on electrical transmission and roadside rights-of-way: a review. Journal of Pollination Ecology, 7.