HITTING THE HOT SPOTS

Storm Water Story

Home

HITTING THE HOT SPOTS

The Storm Water Utility in Wichita, Kan., has an ongoing program to fix small but important drainage and flooding problems

By Rosalie E. Leposky

For stormwater drainage and flooding projects too small to be included in a formal capital-improvements program with bond-issue funding, the Storm Water Utility of the City of Wichita, Kan., has a Hot Spots program funded with Equivalent Residential Units (ERUs).

Each property owner, regardless of property size, pays at least one ERU — a $1.75 monthly charge on their water bill. ERUs are based on property footprint, driveway and average size of impervious areas. For example, a large warehouse store with an expansive roof, building footprint and parking lot may pay several hundred ERUs a month.

Hot Spots projects range in cost from $2,000 to $200,000. Many involve resolution of problems caused years ago by developers who built homes, stores and roads without providing suitable storm drainage. Other Hot Spots projects involve aging drainage pipes — some installed before 1920 — that are deteriorating. They need to be replaced or, in some cases, lined with high density polyethylene (HDPE).

Funding gap

Christopher M. Carrier, Wichita’s public works director, says storm sewer and drainage projects in the Capital Improvements Program (CIP) range in cost from several hundred thousand to several million dollars and are funded with bond proceeds. “We also have small projects that aren’t big enough for the CIP,” he says. “Our Hot Spots budget varies from year to year. It can be as low as $400,000 or as high as $750,000.”

Scott C. Lindebak, a civil engineer in the city’s maintenance division, oversees Hot Spots projects costing $35,000 to $200,000. Debra H. Ary, an engineer in the maintenance division, deals with projects that cost less than $35,000.

“ Debra and Scott and our maintenance division receive a lot of consumer complaints,” says Carrier. “For those, they develop a list of projects. They investigate and analyze complaints, talk to residents, and determine the best way to solve the problems. Debra scopes our smaller reported problems in the field and determines if it’s a repair her department can complete. For larger projects, Scott performs the same process, designing them and taking them through our formal bid process.”

Sometimes Ary and Lindebak conduct surveys and design projects, which may include installing a run of underground pipe or a drain.

Poorly drained terrain

The Wichita area never was farmed. Its hilly clay topsoil has a rocky subsoil layer a foot or two underground. “The confluence of the Arkansas and Little Arkansas Rivers is here in Wichita,” says Carrier. “Our stormwater system drains into these rivers. In the river valley, groundwater is six to ten feet underground.”

The rivers split Wichita from east to west. East Wichita has clay soil and
higher ridges; West Wichita is flatter, with more sandy loam soils. “Debra and Scott look for standing water and for hazards or irritations caused by city installations, including drainage or repair issues,” says Carrier. “Standing water may be a geographic problem because of how and where neighborhoods are built, or because of landscape issues. The issue is generally not soil type but gradient.

“Some developers create problems when they spread extra dirt across a building site and disrupt drainage. With West Nile Virus and other potential health problems, no one wants standing water in their back yard or near their house on a vacant lot or a storm drain inlet. Another problem is stormwater pipes that drain water from developments. We don’t have a lot of grade, and when rivers are up, then our storm sewers back up.”

Allocating resources

When the city is responsible for standing water or a flood hazard, Ary allocates a portion of her Hot Spots budget and hires a contractor. “Sometimes to save time we group together several smaller projects and hire one contractor per year to complete them,” she says.

“Contractors bid an open contract for a full year’s worth of projects. We go with the lowest bidder. Because it’s an open contract and new items may be added, we do a lot of negotiation on unusual items. Contractors complain that they are losing money because of price changes on parts and supplies.”

Ary identifies some projects that she can design but does not have the resources to build. “My budget is easily exceeded when a project needs one or two inlets and a couple hundred feet of pipe,” she says. “My total budget for 2005 was about $200,000, and I did six or seven small projects. This year’s budget is $100,000. I get about a quarter of what Scott does.”

Lindebak now has four projects in design, nine or ten projects out for bid, and five projects he expects to start in the spring of 2006. “One or two projects may carry over to next year’s budget,” he says. “Each year from mid-December to February, we typically can work on designs but we can’t initiate new projects.”

The smallest projects

One small project involved homes built in a subdivision on Wichita’s west side in the late 1970s and early 1980s at the intersection of arterial roads. “Storm flooding began to occur after commercial development and a brick retaining wall was built next to the subdivision,” says Ary.

“We installed a small inlet on both sides of the wall to drain the commercial and residential sides, and we ran a small stormwater line along the residents’ side of the wall to a stormwater line across the street. The total cost was about $20,000. Generally, we don’t address neighborhood issues, but this was an exception due to poor drainage on both sides of the wall.

For the past several years we have worked with subdivision developers to prevent drainage problems.”

Some of Ary’s Hot Spots funding has gone to repair broken storm sewers under Wichita streets. “Storm sewer pipes get old and collapse,” she explains.

Larger projects

An example of a larger project is a site in east Wichita where a subdivision was developed in the late 1960s without storm sewers. Rainwater collects at the site’s lowest point. “Often, such sites drain 40 to 80 acres to one location, causing street flooding,” says Lindebak. “In this case, water was collecting in a home built on the development’s lowest spot.

“The developer is long gone and the city owns the streets and sewers. Storm sewers can cost millions to build. To prevent flooded homes, we have to increase the capacity of the current systems by installing larger outfall pipes feeding into a local creek, and by building an additional storm sewer to drain the street before it reaches the lowest point. Our goal is to collect stormwater before it accumulates in one low location.

“Pavement removal and replacement is very expensive. We have to work around existing utilities lines and sprinkler systems and take down and reset fences — all of which drives up the project’s cost.” In this project, the total cost approached $200,000, of which about $30,000 went for pavement removal and replacement.

Parks and ditches

“Typically our larger projects benefit two or more homes subject to flooding problems,” says Lindebak. “We also fix drainage problems in public parks, and control erosion along creeks and dedicated drainage ditches. About 70 percent of our Hot Spots are reported by residents of our community who live here and see the problems daily.”

In the late 1970s and early 1980s, Wichita pilot-tested corrugated metal pipes buried about 15 feet underground. These stormwater lines are failing and eventually will need to be replaced.

An apartment complex in east Wichita drained its parking lot with such pipes. “We took advantage of a recent street construction project to replace the failing drainage pipe after residents complained,” Lindebak says. “We changed a total of 30 feet — 15 feet in the public right of way and 15 feet through the parking lot. We’ve considered lining some corrugated metal pipes with high-density polyethylene (HDPE) liners.

“HDPE liners are only used in locations where it is prohibitively expensive to use reinforced concrete pipes. Our test trials using HDPE pipes have had problems. We feel strongly that the pipe materials we select have to be cost-effective.”

The City of Wichita’s Hot Spots program has proven to be a valuable service that enables quick response to localized problems and keeps residents happy. Without the program, those residents would have to live with inconvenience while funds were budgeted through the city’s capital improvements program. Hot Spots is an example of an innovative tool for safeguarding the environment and promoting public good will.

April 2006