Exposing a culverted river, creek, or stormwater drainage can improve water quality and hydraulic capacity.

By Richard Pinkham

The modern era has not been kind to streams. As we have enlarged agricultural areas, built roads, and clustered into cities, we have polluted streams, diverted them, straightened them, confined them in concrete channels, put them into pipes, filled their associated wetlands, and otherwise used and abused them. Waterways were often an afterthought, considered a nuisance when it came to the development and growth of a community.

These habits are beginning to change as policy-makers, engineers, and builders increasingly recognize the value of maintaining natural drainage patterns and stream channels–predevelopment hydrology–in new development.

Daylighting is perhaps the most radical expression of this change in attitude and approaches to surface waters. The term describes projects that deliberately expose some or all of the flow of a previously covered river, creek, or stormwater drainage. Daylighting projects liberate waterways that were buried in culverts or pipes, covered by decks, or otherwise removed from view. Daylighting reestablishes a waterway in its old channel where feasible or in a new channel threaded between buildings, streets, parking lots, and playing fields now present on the land. Some daylighting projects re-create wetlands, ponds, or estuaries.

The phenomenon is relatively new. Although projects in Napa, CA, and Urbana, IL, had reexposed creeks in the 1970s, the daylighting of Strawberry Creek in Berkeley, CA, in 1984 is widely considered the archetype of daylighting and has inspired many other projects. In the past decade, daylighting activity has steadily increased across the United States and is even more widespread in parts of Europe.

This article highlights three daylighting projects in the US. Although watershed and site conditions and local politics are different for every daylighting project, and although daylighting involves many technical issues, the examples here can provide useful insights to help those in the early stages of potential daylighting projects.

Benefits of Daylighting

Why would anyone go to the trouble of digging up a culvert and re-creating a surface waterway? There are many potential reasons to daylight a culverted stream or storm drain. Often the benefits are interrelated, but several general motivations exist.

The functional values of opened waterways are important benefits. Exposure to sunlight, air, and soil allows growth of aquatic and riparian vegetation that can improve water quality by taking up organic and inorganic pollutants. The California Urban Creeks Council’s Carole Schemmerling says that a frequent objective of San Francisco Bay Area daylighting projects is to benefit bayshore estuary marshes, which should be dedicated nursery habitats rather than de facto treatment zones. Daylighted, open waterways often have greater hydraulic capacity than culverts. They can slow and infiltrate runoff, benefiting downstream residents by preventing flooding or erosion. Or they can speed its passage in comparison to culverts that might have choked flows and flooded upstream areas. Daylighting is also sometimes a way to remove water from combined sewer systems.

Daylighting projects often happen because they save money. For instance, when a culvert collapses, it might be less expensive to replace it with an open waterway than to reinstall a new culvert, as demonstrated by the Darbee Brook project in Roscoe, NY. Open waterways are also easier to monitor for damage than are buried culverts.

Creating habitat or recreational opportunities, revitalizing neighborhoods, and increasing property values can also be the motivation for daylighting projects. Reconnecting people to nature is a frequent theme of daylighting proponents. In Vancouver, BC, planner Alan Duncan says surveys show people are interested in daylighting and creek restoration because they see restoring salmon as an important regional goal. Finally, daylighting projects give people a sense of "setting right something we messed up."

For stormwater managers engaged in meeting the "public education and outreach" and "public participation and involvement" measures of Phase II of the National Pollutant Discharge Elimination System, the educational benefits of the Blackberry Creek and Darbee Brook projects described in this article have particular relevance.

Daylighting Challenges

In recent decades, restorationists have renaturalized and revitalized many miles of badly degraded surface streams. Daylighting is in many ways a subset of the burgeoning field of stream restoration. Whether a stream is already at the surface or is being uncovered, many of the same principles and procedures apply. Daylighting, however, can involve additional dimensions of complexity:

• Surface stream restorations may or may not require excavation and grading to correct channel alignments and geometries, but pulling up a culvert and creating a new channel where none exists usually does involve a significant amount of earthmoving. It might be necessary to haul away the spoils. These operations add expense.

• Finding the old channel–usually the best place to re-create the stream–can be difficult. It often involves historic research, examination of soils, and looking at the channel characteristics upstream and downstream.

• Existing surface waterways in need of restoration might already have at least a little buffer around them; daylighting projects are more likely to be squeezed for space. The less space, the less chance of creating a natural channel geometry and properly vegetated riparian corridor.

• Additional hydraulic issues might be involved. For instance, it might be necessary to build up hydraulic head to put a daylighted section of stream back into a pipe at its downstream end. Daylighting projects must be carefully engineered into the overall urban stormwater management system.

• Surface stream restorations are sometimes politically easier because the problems are apparent or easily pointed out. With buried waterways, people might be unaware that a culvert carrying a historic stream is under their feet, or that the stream’s absence means degraded water quality, lost habitat, and so on.

• Since there’s "nothing" there now, daylighting projects might require extra community education and outreach to help people visualize the potential. Moreover, creating an open channel often raises fears: kids will fall in and drown, vermin will breed, the channel will flood, or adjacent property owners will face additional environmental regulations. Addressing these concerns is often a big task for daylighting proponents.

At the same time, daylighting projects can generate a level of excitement and dedication that comes from "bringing back" something that once seemed completely lost.

Situations

Daylighting projects have been carried out in all kinds of situations: from small ephemeral creeks to true rivers, in watersheds tiny and large, on rural farmland and in the central business districts of cities. Daylighting projects usually liberate a stream from a culvert; for example, a metal or concrete pipe or arch culvert or a concrete box culvert. But culverting is not the only way people have "disappeared" streams. In some areas, wide bridges and parking decks have covered portions of local waterways. In agricultural areas, streams can vanish from the surface when farmers lace the fields around them with drainage tiles–pipes that provide a new path of least resistance to lower the water table and dry up an area.

Most daylighting projects restore the full flow of a waterway to the open air, but some projects for various reasons keep large storm flows in existing or new culverts. Most commonly, daylighting projects restore brooks, streams, and rivers. But others create ponds or wetlands, often in combination with flowing waterways. Stormwater culverts that run with water only during wet weather can also be daylighted.

Finally, daylighting projects vary greatly in the degree to which they renaturalize a waterway. Most daylighting projects restore an earthen bottom to the waterway and rely mainly on vegetation and woody materials to stabilize channel and streambank soils. They use rocks as naturally as possible, and other hard reinforcements very sparingly. Other projects have confined newly reopened streams more rigidly, reinforcing daylighted riverbanks with granite blocks or concrete-walled and -bottomed channels, not vegetation. These projects–such as the Arcadia Creek project in Kalamazoo, MI, described later in this article–are in downtown locations with severely constrained corridors. While they might not provide some of the values of naturalized channels, they represent important improvements over previous conditions.

Clearly, not every hidden waterway can or should be daylighted. Among the "doable" projects, not every one can be highly naturalized. That said, good design can create more opportunities for naturalization than might commonly be thought.

Challenges

Objectives in mind, what next? Restoration proponents must be prepared for any number of challenges. Daylighting is never straightforward technically, institutionally, or socially. Persistence and a can-do attitude are essential to getting a project implemented. The list below includes just a few of the obstacles that might come up, drawn from case studies and discussions with practitioners of urban stream restoration, to provide an initial "heads-up" list for those considering daylighting projects.

Social. Early challenges might be social and psychological in nature. Landscape architect Gary Mason says the biggest problem can be summed up in one word: fear. Water in pipes doesn’t seem to scare people; water in open channels often does. Among the concerns: Local public works departments might worry about hydraulic performance or object to real or imagined maintenance needs. Neighbors might believe the new channel could be a hazard to their children. Construction might be locally disruptive. And users and viewers of the new creek might expect instant, exotic landscaping. The values of native vegetation are not familiar to many, nor are the successional stages–the "scruffy look" of the early years–that newly established vegetation must go through.

Institutional. Daylighting projects can raise ownership, maintenance, and liability questions. Projects might also present difficulties in coordinating multiple agencies and in permitting. For example, where private property is involved, should a public agency buy the affected property outright or secure a right of way? Who will be responsible for maintaining the project? A buried pipe is typically the responsibility of the relevant public works agency, but responsibility for the daylighted project may revert to the adjoining owners, as would be the case for an open stream. Increased exposure to damage claims for water problems or to personal injury claims might result in increased insurance premiums for owners of the site and those adjacent to it. And creating a surface waterway might also expose owners of the site or adjacent properties to additional environmental regulations and planning procedures (wetlands regulations, setback requirements, and so on), reducing their ability to develop their properties further.

All relevant agencies need to be onboard, but frequently sponsorship by a public agency that will take on the project as its own is essential. Multiple permits will probably be necessary, perhaps from all levels of government: federal, state, and local. The US Army Corps of Engineers regulates almost any alteration to surface waters. Most states have one or more environmental programs that must examine the project. Local planning, construction, or hydraulic modification permits may be required as well.

Technical. Daylighting projects, especially in urban areas, can present a number of technical challenges. Some technical questions are listed here; these are issues that arise in creating new channels, as most daylighting projects do. Projects that produce ponds, wetlands, or estuaries might raise other issues.

Site and Situation

• What’s underneath the site? Will buried utilities have to be avoided or moved?

• What kinds of soils are there? Are soils contaminated from previous land uses or dumping?

• Where is the water table? Will the channel lose or gain water? Is either a problem? Is the groundwater clean or contaminated? Is impervious lining of the channel necessary?

• Does the project require usurping other valuable land uses, such as parking spaces or recreational fields? Can these uses be moved or replaced elsewhere?

• Can the loss of existing desirable features of the site–mature trees, for instance–be minimized?

• What safety features are necessary? Fences, railings, shallow slopes? Grates over culvert outfalls and inlets?

• Will streamside paths be part of the project?

Inputs From the Watershed

• Will sedimentation be a problem? Can and should some sediments be trapped and periodically removed? Can and should the channel be designed to flush sediments downstream?

• What other pollutants will the new stream have to handle? Urban streams typically receive considerable amounts of nutrients and many kinds of organic and inorganic pollutants in stormwater. Are biofiltration strategies upslope of the channel necessary to produce suitable water quality in the channel for supporting fish or other objectives? Can riparian vegetation remove enough of the pollutants?

• Will the new stream carry or collect trash? What strategies can minimize this problem?

Channel Design

• Can the original meanders be reestablished? Can they be found or approximated from aerial photos, measures of the stream sinuosity upstream or down, or by examining soil types along the likely path of the old stream?

• What should the channel geometry be? Relationships between gradient and discharge (flow volume per unit time) must be carefully examined to determine the appropriate channel cross-sections and sinuosity. Often these parameters are substantially different for current watershed conditions than before development. How should this affect placement of the channel? In short, what is the "urban equilibrium" condition given current or projected development?

• What fixed points will constrain channel design? For instance, culverts or bridges for roads and driveways might have to be accepted.

• What additional demands will be placed on design of the channel? Fish habitat requirements are a common consideration.

• Will in-channel structures be used to adjust depth, direction, or velocity? It’s necessary to work with the flow rather than against it. As Gary Mason says, "You have to know what the water wants to do. If you’re not totally respectful of the water, it’ll come back and bite you."

How will any structures be anchored in the streambed?

Streambank and Floodplain

• How much of a floodplain is needed? What is feasible given surrounding land uses?

• What techniques will be used to stabilize the streambanks? Can bioengineering measures–plant materials used to stabilize channels and streambanks–be appropriately anchored in the banks?

• Which native species will be best for revegetation?

• What kinds of plantings are compatible with the site circumstances? For instance, narrow corridors might not allow for tree species that form a large-diameter canopy at maturity.

Project Logistics

• What is the appropriate season for construction and revegetation?

• Will temporary diversion of water flows be necessary? How will it be accomplished?

• How much excavation is required? Can fill and spoils be used on-site to reduce hauling costs?

• How long will the restoration take to stabilize? What follow-up work will be necessary as the site matures? Establishing the new channel hydraulics happens quickly, but full ecological function requires time for slopes to stabilize and a canopy to develop.

• What routine maintenance tasks must be handled?

Costs and Funding

Daylighting projects involve many potentially pricey activities and materials: technical studies and design work, acquisition of properties or easements, excavation and rough grading, hauling of fill, materials for the streambed and in-channel structures, landscaping materials, hand labor for final grading and revegetation, and more. According to Gary Mason, designer and coordinator of several daylighting projects, $1,000/lin. ft. is a good rule of thumb for the full costs of these projects at market rates.

Actual costs for most projects often come out less. Lack of full funding mothers such inventions as use of volunteer labor, in-kind contributions, and donations of services and materials. However, it takes lots of public-spirited people and extremely competent coordination to pull this off.

Daylighting proponents can secure cash funding in a number of ways. Case studies and discussions with experienced practitioners indicate that potential funding sources include city parks budgets; redevelopment authorities, special districts, or economic development projects; public works budgets, especially if daylighting can be rolled into larger projects to improve stormwater management, roads, or sewers; and stormwater utility fees. Funding may also be available from other infrastructure agencies such as highway departments, federal Intermodal Surface Transportation Efficiency Act funds, or state environmental programs (many states have funds for land acquisition or special projects from dedicated bond issues, lotteries, and so on). Some projects have received Clean Water Act funds, such as Section 319 grants, and funding from the US Fish and Wildlife Service Challenge Cost-Share Program and Partners for Wildlife Program. Planners should also consider the possibility of support from local businesses; Community Development Block Grants; donations from individuals, agencies, or manufacturers; and funding from foundations and philanthropists, ranging from local sources to large national organizations such as the National Fish and Wildlife Foundation.

The following three case studies illustrate some of the challenges, funding opportunities, and the importance of involving the community in daylighting projects.

Blackberry Creek

Blackberry Creek area before the redesign commenced

A 250-ft. section of Blackberry Creek in Berkeley, CA, was taken out of a culvert underneath a schoolyard in 1995. Blackberry Creek runs to the San Francisco Bay from the hills in the northern part of Berkeley. The creek flows through a dense single-family-home neighborhood in a narrow but relatively natural riparian corridor upstream from Thousand Oaks Elementary School. At that point it ducks into a culvert running under the school and, until recently, a portion of the schoolyard called the Grove. This culvert had a history of backing up in large storms, with the excess water flooding out onto nearby streets through its catch basins.

The Loma Prieta earthquake of 1989 damaged the Thousand Oaks School and other facilities in the Berkeley Unified School District. When this school’s turn came for structural upgrades in 1992, a local PTA member proposed also improving its "school park" and broached the idea of daylighting Blackberry Creek there. The idea of providing an outdoor environmental education classroom and living lab for the school was a key selling point, as was the opportunity to address the flooding problem and provide a better park for the neighborhood.

Blackberry Creek area under construction

The school district and the Thousand Oaks School PTA obtained a grant from the California Department of Water Resources Urban Stream Restoration Program. Wolfe Mason Associates, a local landscape architecture firm, provided planning, facilitation, and design services. Collaborators included the Urban Creeks Council, the Waterways Restoration Institute, the school district architect, the City of Berkeley landscape architect, and local citizens. Key citizen supporters included a teacher at the school and some businesses along a retail strip one block away. With the money in hand, proponents then educated the neighborhood about the benefits of the project and soothed the usual fears over safety and appearance. They also obtained permits from the US Army Corps of Engineers, the California Water Quality Control Board, the state fish and game department, and local authorities.

Actions. The Waterways Restoration Institute was able to measure upstream reaches of Blackberry Creek to help design the channel geometries for the unearthed reach. These upstream segments appeared to have adjusted to increased flows from development and had reached "urban equilibrium," neither eroding excessively nor silting up. Designers also asked people in the upstream neighborhoods questions like: "Where have you seen erosion occurring?" and "How high did the flood of 1955 get?" They measured water velocities and levels upstream during storm events. They examined original creek meanders in 1940s aerial photographs. All this information helped the designers cross-check and supplement the bankfull channel cross-section indicated for the size of the drainage area by documented relationships for streams in the eastern San Francisco Bay Area.

In September 1995, a heavy-equipment contractor dug out the 1950s-era culvert and roughed out banks and meanders for the new stream channel. Additional bank shaping and landscaping were done by hand, with much of the labor provided by an Americorps crew of the East Bay Conservation Corps, with technical oversight from the Waterways Restoration Institute.

After completion, the Blackberry Creek site offered local families a place to play.

The restoration efforts created 250 ft. of new channel. It drops 2 ft. between the culverts upstream and downstream. To control velocities and orient the channel, the designers specified four shallow rock weirs, each anchored deeply in the streambed. Because the stream channel is 10-13 ft. below the surrounding level of the land, the designs gave close attention to erosion control on the banks. Crews placed large rocks on the outside banks of each meander and stabilized other banks with a variety of bioengineering techniques: fascines, brush layering, pole cuttings, and natural or biodegradable erosion control fabrics. Native dogwood was the species of choice for this project, instead of willow or cottonwood, as local citizens had expressed a preference for shorter vegetation.

Results. The surrounding neighborhood now enjoys a restored 0.6-ac. park with a lawn, creek, creekside path, and picnic area. Thousand Oaks Elementary has become one of Berkeley’s magnet schools, focusing on ecology. Students learn to identify and understand organisms in the restored creek, and they investigate the connections of this reach to the larger watershed. Indeed, students learned a water-quality lesson shortly after crews landscaped the project. Nitrogen leaching from shredded bark and other local organic materials applied as mulch to the streambanks caused a brief algae bloom in the creek. The students worked with the project designers to remove the algae and restore balance to the stream.

Funding. A $144,000 grant from the California Department of Water Resources Urban Stream Restoration Program paid for planning, permitting, grading, hauling away fill, burying the excavated culvert on-site, installing irrigation for the park, and Conservation Corps labor. The school district pitched in $8,000 for fencing at the top of a steep section of streambank and above the headwalls for the upstream and downstream culvert openings. The city contributed $15,000 for concrete work, drainage, and sand for the playground and paid for a staircase leading from the lawn down to the creek. Local businesses and residents donated a few thousand dollars for plants. The design firm reduced its usual fee. If all the funds and donations and foregone fees are totaled, the project probably cost about $200,000. A significant portion of this went toward the playground and park amenities, not just the stream restoration. Not counted in that figure are the many hours volunteers contributed to this project.

Challenges and Lessons. Project designer Gary Mason notes that during project planning, local residents expressed strong concerns about losing the "sure thing" of the older playground on the site. The state stream restoration grant would not pay for play equipment, and the old, substandard gear could not be reused. Eventually the neighborhood took on fundraising for the new playground. This illustrates that daylighting projects can raise concerns about the loss of features now present on a site, even when those features are in poor condition.

Mason also says this project illustrates a common phenomenon: the scruffy adolescence of riparian landscaping. "It’s really messy, and where’s the creek?" is the most common complaint he hears. While lawns, walks, trees, and benches give a finished look to the upland, streamside vegetation must pass through a wild, shrubby, weedy stage before a more mature, familiar canopy develops. Restoration proponents should anticipate some complaints from neighbors and plan a strong campaign to educate the public about what to expect during the five-year establishment period.

Darbee Brook

Before the project: This metal culvert was originally used to direct the outflow of Darbee Brook.

When a major storm blew out a deteriorating culvert on the grounds of the Roscoe Central School in Roscoe, NY, federal emergency aid provided the final funding necessary to implement a previously proposed and partially funded daylighting project.

Darbee Brook is a low-gradient, groundwater-rich tributary to the Beaverkill, a world-famous trout stream in the Catskill region of southeastern New York. The last 330 ft. of the brook was culverted in the 1960s, when the New York Department of Transportation offered the Roscoe Central School roadfill to build up and extend its playing fields into former floodplain. The culvert terminated several feet above the normal water surface elevation of the Beaverkill, effectively preventing fish passage into Darbee Brook for spawning or thermal refuge in its cool, spring-fed waters. While native brook and wild brown trout continued to live in the stream, its value to the Beaverkill system was significantly diminished by the culvert.

The culvert had subsided since its installation, causing damage to the school’s athletic fields. In 1994, when the school approached the New York Department of Environmental Conservation (DEC) about this problem, Ed Van Put and Jack Isaacs of the department suggested replacing the culvert with an open channel. Van Put approached local fishing organizations for financial assistance and secured limited funding from Trout Unlimited.

Daylighting complete: The new mouth of Darbee Brook flowing into the Beaverkill

In January 1996, a major thaw and rain event caused extensive flooding damage around Roscoe, a town of 4,000, and surrounding rural communities. The athletic fields sustained further damage. The Federal Emergency Management Agency (FEMA) provided funding to the school and the region for repairs and measures to mitigate damage from future flooding. At this point, Trout Unlimited went to the school board at the state DEC’s prompting to explain the financial, biological, and hydraulic advantages of returning Darbee Brook to an open channel. The school board voted unanimously for the proposal.

Actions. The DEC’s Isaacs and Trout Unlimited’s Jock Conyngham collaborated on the design. Conyngham says that limited time, funding, and site constraints required design "on the fly"; they could not undertake rigorous geomorphic studies as he would have preferred. The design was mainly based on a few measurements of channel widths for representative riffles in the brook above the culvert. A retired local New York Department of Transportation engineer prepared the construction drawings.

In late 1996, crews constructed a new 160-ft.-long channel, diverted Darbee Brook into it, and then replaced the 330-ft.-long, 48-in.-diameter metal culvert with fill, providing a new, stable base for the athletic field. The new channel was shorter than the culvert because it took a more direct route to the Beaverkill. Contractors also relocated 100 ft. of the open portion of Darbee Brook immediately above the daylighted section, allowing the school to improve and formalize a previously substandard soccer field. The DEC judged that this additional disturbance would not be unduly detrimental to the stream.

The daylighted and relocated brook runs between a softball field and a swimming pool in a corridor about 25 ft. wide. At summer flow levels, the brook gently meanders in a 2-ft.-wide channel through this corridor. The banks are planted with willows, poplar, birch, ash, and other native species. Students and volunteers from local fishing groups and the community did much of the planting and placed a footbridge over the newly opened brook. Volunteers also maintain the new brook.

Results. Electrofishing samples subsequent to the restoration have documented fish entry into the system from the main river as well as utilization of the opened channel by a diverse assembly of aquatic species. Says Ed Van Put, "For once, we were delighted to find hatchery fish in a wild trout stream, which proved fish were coming up from the Beaverkill. I’ve worked for the DEC for 30 years and administered many stream disturbance cases. This was the first time where we could take a stream out of a culvert and make it live again, which was what was really exciting about this project."

According to George Will, superintendent for the 350-student, K—12 school, the restored brook will be the focus of a new environmental science summer camp and the basis for an elective senior science course on water chemistry. The restoration has already augmented two ongoing science curricula. The third-grade "River in Our Backyard" program teaches children how local brooks and rivers, including the aquatic insects and streamside shade trees as well as trout, support the tourism- and fishing-based economy of Roscoe. In the sixth grade, students grow trout in an aquarium, learning about biology and chemistry in the "Trout in the Classroom" program before they release the fish into Darbee Brook.

Funding. Trout Unlimited contributed $9,000 to earthwork, revegetation, and fencing. In turn, its source for this support included grants from the National Fish and Wildlife Foundation, the Trout and Salmon Foundation, Prospect Hill Foundation, the National Park Service, American Forests, and the Orvis Company (a fishing equipment manufacturer).

FEMA funds contributed to the project, but the earthmoving expenses it supported were not separated from other nonstream-related work at the school. Although the school did not make a direct cost comparison, Superintendent Will believes opening the brook was far less costly than the alternative of replacing the culvert, which was estimated at $45,000-$50,000. The school did not incur any out-of-pocket expenses for the project.

Challenges and Lessons. This project illustrates that compromises and tradeoffs must sometimes be made to achieve a daylighting project. According to Conyngham, the new configuration is infinitely better than a culverted brook but less than ideal because it does not include sufficient meander sinuosity in an appropriately sized floodplain. Building those features would have cut unacceptably into the school’s playing fields and incurred significant expenses to move excavated fill. Relocating part of the already open channel was a minor ecological tradeoff, but a worthwhile one to make the project more viable for the school.

Arcadia Creek

The City of Kalamazoo, MI, daylighted a five-block section of Arcadia Creek in downtown as part of a multiyear, multimillion-dollar redevelopment project completed in 1995. While the new channel could not be naturalized, this project does show that waterways can be daylighted in very dense urban centers.

Kalamazoo is a city of 80,000 people at the hub of a concentration of 250,000 people in southwestern Michigan. The city’s economy is diverse and supported by several colleges and universities, regional hospitals, a major pharmaceutical company, and a number of manufacturing firms. By the mid-1980s, however, the northern portion of its central business district was in decline. With rundown buildings, increasing crime, and a history of flooding, this core area had come to be perceived as a risky place for investment.

Aerial view of downtown Kalamazoo with open stormwater pond in the foreground

Arcadia Creek had been buried underneath downtown for more than a century. The creek drains a highly urban watershed encompassing much of the city before joining the Kalamazoo River just east of the central business district. As development in the watershed progressed through the middle part of the 20th century, flooding problems increased because the culvert was not sized to accommodate greater runoff from increased impervious surfaces.

Planning began in 1986 for a 13-block redevelopment project intended to attract business to the rundown portion of downtown. An important part of the redevelopment effort was to reduce flooding by increasing the creek’s capacity. The city formed a Downtown Development Authority to coordinate and fund the project. Land purchases, public involvement in planning, and preliminary engineering continued into 1990. As part of this process, the idea of daylighting Arcadia Creek surfaced during a national design competition for the redevelopment zone. Some citizens complained that exposing the creek would be too costly, but engineering studies revealed that an open channel could provide the necessary flood capacity at relatively low incremental cost over improving and reburying Arcadia Creek’s aging culvert. Also, the overall redevelopment project went through several iterations, which scaled back costs from the original plans.

From 1989 to 1992, the Downtown Development Authority and its consultants completed engineering studies and design work, secured development agreements, and funded the project. Construction took place from 1989 to 1995. STS Consultants Ltd., an engineering firm with offices throughout the Midwest, led the development of the daylighting portion of the project with comprehensive planning and construction management services.

Actions. Kalamazoo daylighted Arcadia Creek through five large blocks of downtown: three blocks of concrete-lined channel and two blocks as an open stormwater pond with grassy slopes for recreation. Room did not exist to create a meandering, naturalized channel and vegetated riparian corridor through downtown at reasonable cost. Also, because impervious surfaces and storm drain systems cover much of the watershed, the groundwater receives so little recharge that the water table has dropped well below the level of the Arcardia Creek channel. An earthen-bottomed stream would lose water into the area’s sandy soils and carry little or no flow except during storms.

Newly daylighted Arcadia Creek. The open concrete-lined channel runs for three blocks between existing buildings.

The newly opened section of the creek first passes through three blocks in an open concrete channel 20 ft. wide by 12 ft. deep, fitted with six weirs that pond water in the channel about 1.5 ft. deep. Without the weirs, the water would ordinarily flow only a few inches deep. The designers felt that an illusion of deeper flow would prove more attractive. At the same time, they kept the weirs relatively low to retain considerable flood capacity between the weir tops and the top of the channel. Slowing water in the channel also causes the creek to drop much of its sediment load there, where a small frontloader can periodically scrape silt off the concrete bottom with relative ease, reducing the frequency of more difficult dredging operations at the earth-lined, grass-banked stormwater pond downstream.

The pond completes the final two blocks of the daylighted section of Arcadia Creek. Its gentle, grassed slopes provide an area for people to relax and recreate. This landscaped area and an adjacent parking lot are also used as a festival site. The total length of the reopened system is 1,550 ft., including the channel, several wide bridges, and the pond. Downstream of the pond, Arcadia Creek passes underground for another nine blocks before joining the Kalamazoo River. In this section, engineers used the existing culvert and constructed an additional new culvert to increase storm capacity.

Results. The combined channel, stormwater pond, and double culvert provide Kalamazoo with protection from a 500-year flood. Authorities have now redrawn local floodplain maps. Downtown properties no longer pay flood insurance, and the perception of flood vulnerability has been lifted.

The flood-protection benefit and amenity value of the creek combine with the overall redevelopment effort to boost the attractiveness of Kalamazoo’s downtown for private investment. Ken Nacci, director of the Downtown Development Authority, puts it succinctly: "What we have is much better than what we had." Public-sector investments of $18 million for the entire redevelopment project have leveraged more than $200 million in private development, including a new museum, a bank headquarters, and other institutions and businesses. Property-tax revenues to the city from the redevelopment zone have increased from $60,000 to $400,000 annually. Activities at the new festival site near the stormwater pond generate an estimated $12 million annually in sales and payroll for local businesses.

Funding. Of the city’s $18 million investment, $7.5 million were related to the creek corridor project, including environmental assessments, engineering, and construction. To pay for the investments, the Downtown Development Authority issued bonds based on tax-increment financing; these bonds are now being repaid by property-tax revenues from the redevelopment zone. Private philanthropic organizations helped reduce costs to the city by funding acquisition of some of the necessary properties.

The Downtown Development Authority pays the maintenance costs associated with the channel and pond (such as sediment and trash removal and mowing). These costs average $50,000 per year–more in years when pond dredging is required, considerably less in other years. "The channel has worked beautifully," says Nacci, "but you do have to maintain it for silt, weeds, algae, and so on."

Challenges and Lessons. This project daylighted a sizable stream in a dense downtown setting. The proximity of the culvert and the new channel to several existing buildings required special measures to shore up foundations during and after construction. Contaminated soils also produced significant challenges. Because Kalamazoo’s downtown was once subject to heavy industrial use, the engineering work for this project included both surface and subsurface environmental assessments. Soils in a number of locations required excavation and replacement; in others, contaminated soils were capped. These structural and environmental measures contributed significantly to the $7.5 million price tag for the stream corridor work, though one capping project saved the city $1.3 million versus the expected costs of excavation.

In addition to the technical solutions to the contaminated soil problems, the city decided to maintain ownership of the land to protect developers from potential environmental liabilities. The city leases out each parcel in the redevelopment zone and indemnifies developers from future environmental problems related to the site.

The aged infrastructure under downtown created some surprises for the city public works department and some property owners. Crews found (and often broke) a number of unmapped water service lines. Also, after they sealed the old storm culvert, some buildings experienced water backups because roof drains or basement sumps had been connected directly to the culvert instead of tapped into official laterals.

The city razed several buildings during the redevelopment effort. This provoked concerns over historic preservation and integration of new buildings with Kalamazoo’s existing architectural flavor. As a result, the city instituted a commission that reviews new buildings for their sensitivity to local architectural conditions.

For other cities considering major projects like this, Nacci stresses the importance of remembering that "things like this don’t happen overnight." Kalamazoo’s project took almost 10 years from inception to completion. And once the construction is done, the work is not all over. Says Nacci, "You can’t build it and let it set there. We still have some available properties and could have done a better job marketing the redevelopment zone to the world."

Conclusions

Daylighting can provide multiple benefits–tangible and intangible–for every dollar expended. These benefits can create many allies for daylighting projects, from citizens and businesses at the neighborhood level to branches of local, state, and federal government.

As more citizens and agencies eye additional daylighting projects, the risk that some projects might be ill-conceived or poorly designed will increase. A notable daylighting failure and its attendant adverse publicity would be unfortunate, both locally and for restorationists nationwide. This article and the report on which it is based offer for consideration the experiences and results of veteran daylighters, both to encourage proponents of new projects and to help them identify potential pitfalls earlier rather than later. With care and attention, streams and people across the country can reap tremendous rewards from this new ambition to resurrect America’s lost waterways.

Richard Pinkham is an independent consultant and an adjunct research scholar with the Rocky Mountain Institute in Snowmass, CO. The complete report is available from RMI at www.rmi.org.

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