Cities strengthening stormwater policies, although builders remain skeptical

CEDAR RAPIDS - Side-by-side 30-unit apartment complexes surrounded by parking lots might normally spell trouble in an age of larger storms and more scrutiny of stormwater runoff - particularly when the property is feet from what's billed as Iowa's only urban trout stream.

Instead, the under-construction Center Point and Creekside Apartments on Center Point Road model the range of practices cities are increasingly requiring to hold rain water on properties so it doesn't flood or pollute storm sewers and creeks.

'Because of the storm systems that have been happening more and more, each property needs to be responsible for holding its water and releasing it slowly so we don't have the flooding we've had,” said Tony Balthazor, project manager for Northcentral Construction Co.

Developer T.W. Sather Co. hired Northcentral as the general contract to build the apartments.

Few would argue against the environmental protections, but the question is whether benefits outweigh costs. It frustrates many builders who argue cities, including Cedar Rapids, are considering demanding expensive add-ons with little proof of results.

'There's not a lot of new rules from the (Environmental Protection Agency) level, but many municipalities are starting to get on the feel-good bandwagon without the science behind it,” said Drew Retz, vice president of Cedar Rapids-based Jerry's Homes Inc. and a past president of the Homebuilders Association of Iowa. 'Every requirement has a cost to that, and the buyer of the end product will pay for it.”

At the Center Point construction site, where the ground still is being excavated, water will soak through the apartment parking lots surfaced with permeable pavers and filter through the soil to 2,200 lineal feet of perforated storage cells with capacity for 30,000 cubic feet of water, buried about 10 feet underground.

Three depressed bioretention basins will help capture water and filter out pollutants. Trenches that carry water away from the property will be lined with gabion baskets, which inhibit erosion.

All told, the system is supposed to handle a 1.25-inch rain event and detain 2.4 inches of rain over a 24-hour period, which would protect against 90 percent of Iowa's rainstorms. Cedar Rapids requires 1-inch of rain infiltration.

Any water dispersed into McLoud Run will be cooled and cleaned of sediment and toxins, which is essential to not disrupt the trout stream's delicate ecosystem. The developer Tom Sather called it 'the most environmentally-sensitive and energy-efficient buildings that we have built” in his 20 years building apartment complexes.

'It's all environmentally friendly, but it comes at a cost,” Balthazor said.

Balthazor estimates the $10 million project could have been completed for about a third less, or about $7 million without special features. The parking lot alone costs $1.4 million, but could have been $450,000 if it were a traditional asphalt.

In this case, $6 million in Community Development Block Grant disaster funds to replace housing lost to flooding offset the extra costs, but in other cases 'going green” can be the root of head butting between developers and cities.

One not-so-environmental aspect of the apartment project is they had to cut down numerous trees to build.

Cedar Rapids is in the midst of strengthening its stormwater management policies to battle flash flooding, soil quality issues and water pollution. This project is an example of the direction many communities are heading with development.

Cedar Rapids staff are proposing requiring eight inches of topsoil remain after a property is developed. The city estimated it could add about $3,330 to the cost of a home but developers claimed it would add more than $10,000.

The city also started this fiscal year a cost-sharing program in which stormwater utility users can apply for grants to cover 50 percent of costs up to $2,000 for water infiltration practices supported by the Iowa Storm Water Manual. The city received two applications thus far, but neither were successful.

The city also recently won a $100,000 grant from the Iowa Department of Agriculture and Land Stewardship for the development of four Stormwater Best Management Practice pilot projects. The city also recently joined the fledgling Middle Cedar Stormwater Management Authority to share the responsibility for water issues with communities along the river.

'The thing about green infrastructure is ultimately to work well for flood mitigation it needs to be widespread across the community,” said Sandy Pumphrey, a Cedar Rapids project engineer. 'You can't just put it in one place and expect it be the silver bullet.”

Pumphrey acknowledged the city can't statistically prove how successful stormwater management practices are at removing pollutants or slowing water flow, but rather the proof is in the underlying engineering.

The practices are detailed in the Iowa Storm Water Manual, which is maintained by the Iowa Department of Natural Resources and is considered a bible for many cities around the state.

'For the effectiveness, I would say we are relying pretty heavily on the past research that is the basis for the manual," Pumphrey said. "At this point we don't have a plan to put flow monitors or pollutant monitors in every little practice. I don't know that would be practical.”

Alex Schmidt, a landscape design professional with clients in Linn and Johnson Counties, is an elected member of the Johnson County Soil and Water Conservation District and is the Regional 7 director for the Conservation Districts of Iowa Board.

Schmidt said several cities across the state are tightening stormwater policies, a movement supported by science. The costs are overstated, he said.

'It is because of flooding,” Schmidt said. 'It is because people are more cognizant of the watershed they live in and not wanting to add more water and pollutants to the system.”

Cities such as Cedar Rapids and Coralville have been trying to model best practices for the private sector.

The new Cedar Rapids Public Library, which covers nearly all of its parcel of land, has a green roof that helps the property retain 90 percent of annual rainfall. Coralville has been experimenting with permeable pavement and tree boxes along its street right-of-ways.

Coralville is seen as having some of the strongest stormwater management policies in Iowa, and was recently featured on the cover of the American Public Works Association's monthly newsletter as a national example of positive stormwater management efforts.

Since passing a post-construction stormwater management ordinance two years ago, 28 developments have been completed, showing strong policies are both practical and won't scare off development, said Amy Foster, Coralville stormwater coordinator.