Ready To Ride
By Ali Weber
Etched into the natural terrain of an 80-acre urban park is Denver Parks and Recreation’s (DPR) Ruby Hill Bike Park. Unveiled in July 2016, Ruby Hill, the largest public bike park, is a 7.5-acre premier recreation and play experience that features a slopestyle course, dirt jumps, pump tracks, a skills course, and a 1.7-mile loop trail around the park’s perimeter.
With more than 50 feet of elevation difference between the top and bottom of the bike park, the natural topography, paired with sights of the city skyline, boast an enthralling riding experience. The gravity-fed slopestyle course and dirt jumps provide lines of varying difficulty, from beginner to advanced. The continuous loops of two pump tracks—small and large—offer opportunities for riders of any age and skill level, from small children with pedal-less “strider” bicycles to seasoned adult riders, to build confidence. The skills course beckons beginner and intermediate riders to test their abilities on a variety of features designed to improve balance and bike handling. Ultimately, the diverse landscape and location invite riders of all ages and skill levels to get their wheels spinning!
The trending addition of bike parks to public spaces is turning heads nationwide. Ruby Hill Bike Park’s popularity serves its purpose, but proper maintenance is essential. One of the core elements of upkeep includes irrigating the bike park to maintain dirt jumps and trails. Irrigation stabilizes the moisture necessary to preserve dirt for repeated rides. Under-watering produces dry dirt that will crumble, erode, and disintegrate. Over-watering drowns dirt, which washes away fine soil, floods features, and generates unwanted mud. That is to say, the purpose of irrigating the bike park is centered on stabilizing moisture for long-lasting, ride-ready dirt.
DPR’s Bike Park Operations Supervisor, Deak Brown, lends insight on the strategies behind attaining and sustaining successful irrigation of bike parks. Here are five keys to irrigation that he has integrated into preserving features for riders’ unending enjoyment.
1) Honing In On Zones
Irrigation zones are foundational for precisely controlling desired water distribution. Ruby Hill Bike Park has separate zones for trails, native grass, and trees, but the focus here is on the dirt trails. Of the bike park’s 44 irrigation zones, 14 cover the dirt trails. The slopestyle course is divided into eight zones, and the dirt jumps, pump tracks, and skills course have two zones each. Altogether, these zones irrigate 1.81 miles of dirt trails. “Fundamentally, each trail at the bike park has its own zone so an entire trail can be evenly watered at once. This is the key to zoning,” Brown explains.
2) Calculating Coverage
The precipitation range and radius of heads and nozzles in an irrigation system determine water coverage. The traditional head-to-head coverage of most sprinkler systems spaces heads so they overlap from one head to the next; typically, every head dispenses water far enough to reach the subsequent head. “This is not the case of the bike park,” states Brown. “Our sprinkler layout is approximately half of traditional head-to-head coverage. Rather than a 100-percent overlap, the bike park has a 60- to 70-percent coverage overlap.” Traditional head-to-head coverage showers too much water on dirt, causing problems associated with flooding and mud. The coverage setup of minimal overlap ensures that dirt receives just enough water without dry spots. Advantageously, the long and skinny trails require fewer sprinklers than an irrigation system with traditional coverage. Brown continues, “The purpose was twofold in safeguarding dirt from getting oversaturated, as well as stewarding resources by reducing time and money that more heads would require.”
3) The Necessary Nozzles
Sprinklers at the bike park use matched precipitation rate (MPR) nozzles, meaning sprinklers in each zone are “matched” with the same distribution rate of precipitation. The average trail width at Ruby Hill Bike Park is eight feet, so each spray head uses a MPR nozzle with a 10- to 15-foot radius. While throwing a short distance, MPR nozzles fan water lightly and equally per the arranged coverage. “Our MPR nozzles have a low precipitation rate, which evenly saturate the dirt jumps and trails to retain optimal moisture. They minimize fine soil from washing away and prevent water waste from run-off,” says Brown. The most common nozzles are half-circle and quarter-circle spray nozzles, but there are some full-circle nozzles for specific areas along the trails, such as switchbacks with 180-degree corners.
4) Weighing The Weather
The first three keys involve the technicalities behind a successful irrigation system, while the remaining tactics zero in on meeting unique needs to attain sustainability goals, such as the evaluation of climate.
Climate should always be considered when it comes to irrigation, and systems must be adjusted according to seasons and weather conditions. Since Colorado has a dry climate with changing seasons, the irrigation at Ruby Hill Bike Park fluctuates. Hot summer temperatures normally last from May through September and necessitate more water than in other months. Watering does not occur as often in spring and fall, so water is shut off and winterized when snow falls. “Anyone who has traveled to Colorado knows weather can be very unpredictable, but we aim to keep the bike park open year-round,” Brown expounds. “Our irrigation pattern involved some trial and error, but I would recommend others do the same in figuring out how to optimize moisture by taking their climate into account and making the weather a friend, not a foe.”
5) A Frequency Formula
Trial and error has worked for Brown. Last but not least, he answers the questions of when to water and how long to water the bike park in order to sustain dirt jumps and trails.
Trails should be watered for short but frequent amounts of time and by zones. Times might vary depending on the climate, but those are the main parts to the pattern. “During the scorch of the season, our dirt trails are irrigated for two minutes every two hours each day of the week during the peak heat of the day, which is usually from 12 p.m. to 8 p.m. On cooler days, the time drops to one minute every two hours. In the spring and fall months, the numbers change to one minute every three hours. Of course, we keep an eye on the weather and always adjust accordingly.” These scheduled changes are easily managed at the bike park through DPR’s central-control irrigation system and remote controls for the field. A formula with short and frequent watering times is crucial to stabilizing moisture in the dirt jumps and trails of the bike park so they are not too dry and not too wet for ideal riding conditions.
Adopting These Keys For Success
These strategies have played a big role in the maintenance of Ruby Hill Bike Park, and hopefully they will make a positive difference for those overseeing similar amenities. “Riding a bicycle has been compared to tying a shoe—it’s something almost everyone has done and can do,” Brown points out. “I love preserving a place that brings people together to practice and play a renowned pastime and a thriving sport. Above all, I always want the park to be ready to ride!”
To learn more about Ruby Hill Bike Park, visit www.denvergov.org/bikeparks.
Ali Weber is in her fourth year of working for Denver Parks and Recreation’s (DPR) Department of Maintenance Operations, where she is a Staff Assistant to the Superintendent of the Southwest District and the six Operations Supervisors therein. Her role intertwines administrative responsibilities, special projects, and event operations for permits in the parks. DPR’s park system encompasses 250 urban parks (6,000 acres), more than 14,000 acres of pristine mountain parkland, and over 80 miles of trails. DPR also manages 27 recreation centers, eight golf courses, ten dog parks, and numerous programs and amenities. Reach her at Ali.Weber@denvergov.org.