Oelwein, IA

Water Distribution Pressure Zone Improvements

  • Client City of Oelwein
  • Type Municipal
  • Services Water Improvements
  • Construction Cost $633,700
  • Project Manager John Gade, P.E.
  • Project Engineer Mitch Holtz, P.E.

Challenge

Oelwein was founded in a low lying area and expanded to higher ground as the population grew. The change in elevation between opposite sides of the city produced a water pressure differential of up to 50 psi across the town. Inconsistent water pressure to customers and deficient fire flow availability in some areas compelled the city to find ways to improve the water distribution system performance. In 2007 the City selected FOX to utilize the city’s existing GIS information to accurately and efficiently generate a water distribution model to simulate potential solutions. Many alternatives were considered and through computer analysis, it was determined that separating the city into two pressure zones was the most cost-effective, long-term solution.

3rd Ave. NE and 1st. St. NE water pressure out of hydrant after3.5 hours of flushing

Solution

FOX provided design services associated with isolating the City into two pressure zones. The project was challenging due to 13 construction zones throughout the City. In addition, portions of the water main were routed within a city park, roadway crossings, railroad crossings, and private property. This required twelve (12) isolation valves and blowoffs to be installed on existing main (removal/replacement of streets). The project included 1-mile of 12-inch water main through railroad ROW, floodplain, Wings Park, private property, and the Oelwein Schools. The project, which went through a residential neighborhood, included replacement of over 2,000 feet of 10-inch water main that was over 100 years old.

FOX worked with City Staff to meet with property owners to acquire easements, introduce the project to the public, and coordinate with stakeholders.  FOX obtained permits from the D&W Railroad, IDNR Floodplains, Army Corp of Engineers, and the IDNR Water/NPDES. The route was placed in our water modeling software to evaluate the design flows and evaluate pipe materials/sizing, and pressure zones.

12 inch main Sta. 4443 fire hydrant assembly

12 inch main Sta. 4443 fire hydrant assembly

Outcome

FOX provided construction administration services, part-time observation services, and construction staking. There were five (5) change orders on the project totaling $29,080 (4.8% increase). In addition to separating the distribution system, an existing well house was in need of replacement. In an effort to reduce redundancy in equipment and buildings, the existing well was incorporated into the new booster station facility. Currently, the booster station is in operation and city staff is gradually increasing the system pressure to residents on the new high-elevation zone while maintaining the same level of service to the customers on the low-elevation zone.

Sta.3750 12 inch main bore pipe assembled before pulled through

Sta.3750 12 inch main bore pipe assembled before pulled through