Iowa has an acknowledged water quality problem.
On Monday, Iowa Secretary of Agriculture Bill Northey visited Davenport to highlight the awarding of a $31,875 grant to fund a project expected to improve water quality at one specific location — Duck Creek near East 32nd Street. It also will serve as a model for similar projects elsewhere if it works.
The installation is the first of its kind in a urban setting in Iowa and possibly the nation, Brian Stineman, manager of natural resources for the city of Davenport, said.
The project is an underground system in which water from a city storm drain pipe will be diverted from going directly into the creek, untreated, and will instead go to a "bio-reactor."
The latter is an underground trench about 25 feet wide and 100 feet long filled with wood chips. The diversion will slow the flow that normally would gush into the creek during typical storms, and it will filter out pollutants, Lindsay McFarland, of Partners of Scott County Watersheds, said.
Partners is a collaborative program operated out of the Scott County Soil and Water Conservation District, with funding from various sources, including the cities of Davenport and Bettendorf.
After moving through the bio-reactor, the water will collect in a pipe and flow toward the creek where it will be intercepted by a water level control structure made of steel and hard plastic that will cause the water to back up and flow into 1,000 feet of perforated pipe sunk parallel to the creek. Once in this pipe, the water will slowly seep into the ground, or the saturated buffer zone between the bike path and the creek, being further cleansed in the process.
Both the bio-reactor and buffer zone are expected to filter out nitrate, phosphorus and E.coli that contribute to poor water quality in much of Iowa.
The project is designed to handle up to a 1½-inch rain, which accounts for about 90 percent of storms. If the rain is heavier, it will bypass the control structure and go into the creek, as it does now, McFarland said.
The sewer pipe that will be diverted collects water from three storm drains in 32nd Street at Fair Avenue, collecting water from about 11 acres. The city has 81 similar pipes within 500 feet of Duck Creek, Stineman said.
Once the project is installed this summer, employees of the city of Davenport and Partners of Scott County Watersheds will conduct tests to see how effective it is. The goal is to provide information needed to build similar installations in other cities and at the county and state level.
"We're hoping to lead the way," McFarland said.
Added Northey: "This should be a very interesting program to watch."
The Davenport project is one of 13 urban water quality demonstration projects receiving $978,149 in funding.
The total cost of Davenport's project is $68,250, with the remainder supplied by the "in-kind" contribution from the city of wood chips and labor to build the installation. The grant money will pay for the design and engineering by Ecosystem Services Exchange, a national firm with offices in several states, including Iowa and Minnesota.
These relatively new practices already have been introduced in some rural areas where they are used to treat water from farm drainage tiles before it flows into streams.
The issue of farm tiles has taken on greater significance since the filing a year ago of a lawsuit by the Des Moines Water Works against three rural Iowa drainage districts, arguing that the tile water introduces nitrate and phosphorus into streams and should be regulated by the federal Clean Water Act.
The water works gets its water from the Raccoon River, fed by streams in the drainage districts, and it must spend large amounts of money to filter out nitrate to make it safe for drinking.
Iowa now has a voluntary Nutrient Reduction Strategy that was adopted about 3½ years ago. It aims to reduce by 45 percent the amount of nitrogen and phosphorus flowing down the Mississippi River to the Gulf of Mexico where they cause a "dead zone," Northey said.
Critics have argued that the strategy doesn't go far enough because there are no mandatory requirements and there is no deadline for reaching the reduction goal. They also question why, when 90 percent of the nutrients causing the "dead zone" can be attributed to agriculture (farm fertilizer and animal operations) and 10 percent to industry or city treatment plants, only the 10 percent is regulated.