Advanced Trail School in Action: Solving Hagg Lake’s Water Woes

Written by Bob Carey

For those who have biked or hiked the trail that circumnavigates Hagg Lake, you have probably noticed some wet, muddy, or downright sloppy sections. NWTA crews have been consistently working to address these trouble areas with Washington County since 2024. When the Trail Sustainability Institute (TSI) instructors were looking to teach an Advanced Trail School for complex drainage issues, they knew to set their sights on the Hagg Lake trail. 

To set the scene, the trouble area stretched roughly 40 yards, starting at the top of the 10% grade trail where years of water flow and erosion have cut into the trail, creating a deep ditch/trench measuring up to 2 feet in depth. At the bottom of this ditch, the land becomes nearly flat, and the water that runs down the eroded ditch is met by a slow-flowing, seasonal creek that crosses the trail, resulting in standing water that stretches across a 15-foot section of the tread. A complex drainage issue, indeed!

Despite morning temperatures in the low 30s, volunteers got to work assessing the area, pinpointing the multiple sources that contributed to the drainage issues. From there, a plan was laid out for the different stages of repair. 

The crew assigned to the ditch section began the work of shaving down the edges and using that dirt to fill the ditch, alternating the fill with 1.5″ drain rock, compacting that layer, and starting the process over again several times. In an effort to minimize the amount of water that travels down the trail in the future, multiple-grade reversals were built to direct water off the trail and into a drain downslope. 

Meanwhile, the crew assigned to the standing water section started clearing vegetation, making it possible to establish a sloped drainage ditch — essentially, a pipeless french drain to provide several years of effective drainage. The crew was mindful that the ditch sloped about 2 inches or more every 10 feet to ensure water flow. They then lined the ditch with drainage fabric and filled the ditch to the top with rock, and it immediately started transporting water! 

Although the day started out freezing cold, everyone was rewarded with a lakeside lunch break, showered in that elusive winter sunshine. 

This project would not have been possible without the support of the Washington County Park Rangers and the much-needed materials and transport that they provided. Also, a big shout of thanks to all of the volunteers who spent their day improving this trail for the enjoyment of so many others. 

If Trail School is of interest to you, please join us at the upcoming Trail School Fundamentals at Hagg Lake on March 2nd or Advanced Trail School: Reinforcing Berms at Sandy Ridge on April 13th.