The city of Fort Morgan, Colo., experienced regular flooding caused by both rain and snow melt. To solve storm water issues and revitalize the historic Main Street, 18,000 feet of Pavestone Eco Priora 8 cm permeable pavers along Main Street were installed. Winter blend and limestone colored pavers were used to differentiate parking spaces and street markings. Already, sudden downpours that would have previously caused flooding have cleared the new drainage system with ease.

 

Every week, the city uses vacuum street sweepers to clean the permeable pavers without damaging joint aggregate, which preserves the integrity of the stormwater management system and reduces long-term maintenance cost.

Located on the northeast plains of Colorado about 80 miles from Denver, Fort Morgan offers nearly 11,000 residents a beautiful, quaint setting to call home complete with a historic downtown business and entertainment district. However, as a home-rule municipality that oversees all utilities, Fort Morgan is responsible for addressing frequent flooding caused by heavy rains, and snow and ice melt that are common each year. After years of repeated damage to storefronts, the City of Fort Morgan executed the Downtown Infrastructure Improvement Project in 2009 to minimize the negative impact of flooding on businesses and visitor traffic on Main Street in the downtown district.

The Downtown Infrastructure Project significantly upgraded a variety of important structural and aesthetic city elements including roads, sidewalks and surrounding landscaping that are vulnerable to damage caused by uncontrolled flooding, but are also critical to the overall downtown experience. However, it all started with replacing the drainage system that was not only outdated, being over 40 years old, but was significantly undersized for the area.

''The main objective of our Downtown Infrastructure Project was to resolve recurring flooding issues by replacing the aging underground infrastructure in one of the oldest streets in the city,'' said Public Works Director Brad Curtis, PE. "We elected to incorporate permeable interlocking concrete pavers into the design to help reduce the need for peaks and valleys along the roadway normally required for positive drainage flow. As well, we assumed these would also reduce the potential for icing, all while enhancing the downtown aesthetics. We installed 18,000 square-feet of permeable interlocking concrete pavement (PICP) from Pavestone for the designated angle parking areas between the street and sidewalks." Rocky Mountain Hardscapes, one of the largest commercial paver installers in the Colorado market and an HNA award winner, was enlisted to complete the project.

Impermeable geotextile liner and PVC pipes were installed below the aggregate to channel drainage into the storm water system. The aggregate consists of three layers of fractured washed open graded stone between the geotextile liner and the pavers, providing a filtration system to reduce contaminants from the water before it is released into the storm water system.

The existing sidewalk and red pavers remained unchanged through the project, which took a 5-person crew 30 days to complete. The addition of the aggregate and permeable pavers leveled Main Street from an eight percent to a two percent crown, which allows for proper drainage during both major and minor rain events.

In addition to directing excessive rain and melted snow and ice to an under drain collection system, the zero infiltration PICP design has aggregate layers within the permeable paving section to act as a filter that reduces contaminants from the water before discharging into the storm water system.

''We eliminated the eight percent crown on Main Street that was created by multiple overlays throughout the years, back down to the traditional two percent,'' said Curtis. ''The pavers allow for proper drainage in smaller rain events without the need for multiple inlets. Smaller rain events never get runoff to the gutter. As well, we've had trouble with ice build-up that sometimes would not allow parked cars to back out, an item we have had no issues with since the installation of the new pavers. During extremely heavy storm events, we may get water over the curb line, but it quickly works its way into the drainage system and is not a constant occurrence as it was in the past.'' As part of the stormwater management system, Fort Morgan sweeps all 54 centerline miles of city streets each week with vacuum street sweepers. Taking this diligent approach has successfully maintained the integrity of the system, including cleaning the permeable pavers without removing any joint aggregate, which could otherwise jeopardize how well the surface allows infiltration. In addition, Fort Morgan is among the leaders of municipalities in Colorado to take the thoughtful foresight to use polyurethane blades rather than steel blades on all of its snow removal equipment. While preserving the city's asphalt and concrete roadways, the polyurethane blades also help to avoid scratching, chipping or otherwise damaging the pavers. Taking this proactive approach in keeping the PICP and other conventional surfaces clean, along with the use of colored pavers for the striping of parking spaces will reduce long-term maintenance costs for Fort Morgan.

As for the local businesses, the Downtown Infrastructure Project has proved to be a huge success, Jim and Deb Forstedt, owners of Fort Morgan Furniture, no longer have to spend countless hours each winter removing snow and ice while pushing customers' cars from parking spaces. They no longer have to be concerned that a customer might slip and fall while visiting their store, which has been open since 1946. They no longer have to be concerned that flooding could create impassable streets and prevent customers from shopping at their store. In fact, according to the Forstedts, a 45-minute downpour this summer that produced 2.5 inches of rain caused no issues and the pavers dried quickly as a result of the new stormwater management system.

While no permeability testing on the streets has taken place, visual anecdotal evidence from Curtis shows nearly a 100 percent capture (no run off) in minor storm events. Curtis concludes, ''By using a permeable interlocking concrete pavement, downtown Fort Morgan is serving as a perfect pilot project for the city as we further address our storm-water related infrastructure needs.''

''Although this was mainly an infrastructure project,'' said city manager Jeff Wells, ''efforts enhanced the attractiveness, convenience and functionality of the downtown area while improving pedestrian access and safety.''