Buried Treasure

Beneath the city -- 60 feet underground in some places -- there is a creek. Its main branch begins near 8th and Xanthus. The creek flows to the west via storm sewers, then runs south-southwest through a 15-foot high arched tunnel, built in 1922. It runs beneath Gunboat Park, to the west of 18th and Boston, beneath Veterans Park, then empties into the Arkansas River near the 21st Street Bridge.

This is Elm Creek. It drains 3.4 square miles of neighborhoods and industrial areas to the east and south of downtown.

The Elm Creek basin has developed considerably since the creek was buried. This octogenarian storm water system is overwhelmed. Every two to 10 years, we can expect a rain heavy enough to cause water to back up into streets, yards and basements, high enough to reach floor level.

According to a recent study, there are 523 buildings within or near the 100-year floodplain of Elm Creek and its tributaries. Hydrologists expect an annual average of $3 million in flood damage.

Included in the upper Elm Creek basin is an area that links downtown, the University of Tulsa campus, Kendall-Whittier neighborhood and Hillcrest Medical Center. Centered on Sixth and Peoria, it's known as the Pearl District, after the original name given to that stretch of Peoria Avenue.

East of Peoria on 6th Street, you'll find some handsome brick buildings, many of them two stories, the sort of buildings that have been transformed into trendy eateries and boutiques in the Blue Dome district and along Cherry Street.

But the buildings on 6th Street sit right in the middle of the city's regulatory flood plain, a significant deterrent to investment. The potential for flooding plagues nearby residential areas, too.

Following a series of disastrous floods in the '70s and early '80s, culminating in the deadly Memorial Day 1984 flood, Tulsa has become became a leader in flood prevention, winning national recognition and taking thousands of acres of land out of the flood plain.

But a quarter of a century later, there are still a few Tulsa creeks that haven't received the attention they need. Because so much of the land is developed above and around these urban creeks, it's a challenge to add upstream capacity. Where do you locate detention ponds? How disruptive and expensive will it be to dig up the streets to install bigger pipes?

Elm Creek is one of a handful of flood zones remaining to remediate. The area was first studied in 1988, but the resulting plan was deemed too expensive. Central Park would have been wiped out by an enormous detention pond. The resulting protection was considered insufficient to justify the cost to the city and the disruption to the neighborhood.

A 1998 study proposed the construction of four detention ponds, this time in more acceptable locations, but for all the expense, the plan still left too much property in danger of flooding.

Just a year or so later, the city launched an infill development study of the 6th Street Corridor. Residents, business owners, property owners and nonprofit leaders worked together during a six-year period on a plan to revive the area as a close-in, urban, densely-settled, mixed-use, pedestrian-friendly area.

In 2006, the Pearl District plan was adopted by the City Council and incorporated into the City of Tulsa Comprehensive Plan.

The plan included a new flood control concept to replace the earlier proposals. There would be a new pond built in Centennial Park, as well as two additional storm water ponds. A canal would be built connecting the east pond to Centennial Park.

The Centennial Park pond, a beautifully landscaped, award-winning storm water detention facility, has already been completed, along with the new Central Center, which sits on its north shore.

Neighborhood leaders had hoped for enough funding to implement the plan in the 2006 sales tax package, but only $2 million was included. It was a drop in the bucket but sufficient to fund final design and some land acquisition.

Recently I spoke to Dave Strader, president of the Pearl District Association. Strader has been involved for many years, advocating for the neighborhood since 1985.

Strader told me neighborhood leaders had been working closely with representatives of Guy Engineering to come up with a plan that provided flood control while retaining and reinforcing the urban, walkable character they wanted for the Pearl District. They didn't want several big holes in the ground. They didn't want just another soccer field.

They wanted to retain, as much as possible, the urban street grid, which provides a variety of paths through the neighborhood for pedestrians, cyclists and motorists.

Rather than acting as experts presenting a done deal, the design team took an approach similar to that of PLANiTULSA, presenting a number of options and then taking into account the suggestions and concerns presented by the neighborhood.

The resulting design was on display at a public hearing earlier this month, which drew about 150 people. (You can see the concept drawings on the Web at www.guyengr.com -- click the Pearl logo at the bottom of that page.)

There are four main elements to the plan. The first is already complete, funded with TIF (tax increment financing) dollars: An award-winning, beautifully landscaped lake in Centennial Park which also provides 58 acre-feet of floodwater storage.

Two more detention ponds are planned: West Pearl, a 4-acre pond northwest of 5th Place and Owasso Avenue, and East Pearl, a pond and sunken-gardens area near 8th Street and Rockford.

A typical Tulsa storm water detention pond is open, grassy and surrounded by more open and grassy land. Many ponds serve as soccer and baseball fields when they're not needed to hold flood water. Building that sort of pond in the Pearl District would have reduced the area available to accommodate new residents and jobs.

The engineers and neighbors, working together, developed a more urban approach. Rectangular ponds and sunken green space would provide the needed storm water storage during heavy rains, while allowing the street grid to remain largely intact, with buildings along the streets, backing up to the ponds.

Perhaps the most revolutionary aspect of the plan is to connect the East Pearl pond with the Centennial Park pond via a 10-foot-wide canal that will run down the center of 6th Street for three blocks between Rockford and Peoria. The canal will be the centerpiece of the transformation of 6th Street into a shared street.

The shared-street concept allows for slow-moving auto traffic but gives pedestrians priority and the right to enjoy the full width of the street. A nine-foot wide area along the building fronts on the north and south sides of the street would be reserved for pedestrians and uses like sidewalk cafés. This pedestrian-only area would be protected from cars by bollards instead of curbs. Cars would share with pedestrians a 12-foot wide lane in each direction, between the canal and the pedestrian-only zone.

Strader called this a "signature development." There's nothing like it anywhere in the United States, he said. It originated in the Netherlands, where it's known as a woonerf, which roughly translates as "courtyard for living." (Woonerven is the plural, if you were wondering.)

For a time, 7th Street was a possible path for the canal, but 6th Street was chosen for its diversity of the existing building types. It provides the best chance for retail development, Strader said.

It took some doing to get the approval of the fire marshals, who were worried about getting trucks down the street, and the transportation engineers, whose focus is moving as many cars as possible as quickly as possible.

Strader said they "really had to go to school," but supporters of the plan were able to bring the fire and street planners around to their way of thinking, showing them how the concept complied with their regulations.

Implementation of the entire plan will cost about $58.9 million, which Strader said is the equivalent of building just one south Tulsa intersection.

For less than a tenth of the cost of creating 40 acres of islands in the middle of the Arkansas River, a half-square mile neighborhood -- strategically linking downtown, the Utica medical corridor and TU -- could be positioned for restoration and redevelopment.

Full implementation of the new storm water plan would reduce average flood damage in the Elm Creek basin by more than $2 million a year. The plan takes nearly all of the residential areas out of the floodplain, including Gunboat Park and the area southwest of 15th Street and Boston.

Some residential areas upstream of the new ponds would remain flood prone, but a voluntary acquisition program in those areas will allow property owners an economical way out.

For the moment, funding isn't available to make this big plan a reality. About $1.5 million will be left from the 2006 sales tax money. City officials may be able to use that to attract matching federal flood mitigation funds.

According to Strader, Mayor Kathy Taylor did not include the Pearl District in her list of "shovel-ready" projects for President Obama's "spendulus" package, but she has told Pearl District leaders that she will create a panel to look for funding. Meanwhile, supporters are looking at ways to divide the project into phases so that it can be built a piece at a time as money becomes available.

City planners, citizen planners and engineers have worked together to come up with a solution to a public safety problem that also makes for good urban design.

Strader calls it proof that grassroots-initiated planning does work. It's a long process, and citizens have to learn the system, but he has full faith that this problem will be solved to the satisfaction of everyone involved.

There's even more to the story of the Pearl District and its progress, but it will have to wait for a future column. Until then, check out TulsaPearl.com.