When Mike Taylor purchased New York’s Holiday Mountain Ski and Fun Park in May 2023, it was teetering on the brink of disrepair. Washed-out motocross trails replaced what were once vegetated ski trails, funneling water and dirt into places it didn’t belong.

Instead of investing to update and maintain the ski area’s infrastructure, the previous owner built this network of motocross trails around the mountain, exposing naturally sandy soils to the elements without implementing best management practices (BMPs) to manage the stormwater that inevitably would flow through the property.

“They didn’t put anything in to direct the water when they built the motocross track,” says Taylor. “The water went everywhere and made channels that got worse and worse until the water became uncontrollable. Our lodge flooded numerous times with muddy water, and sand and soil were getting dumped all over our fun park.”

Action steps. For the past 18 months, Taylor and his team have been working to install and implement BMPs—structural measures like culverts, swales, and treatment ponds, and non-structural measures like stormwater education and maintenance—to regain control of stormwater and mitigate ongoing erosion. They’ve constructed and installed a network of water bars, retention ponds, silt fencing, hay bales, erosion control blankets, riprap, and other BMPs to minimize erosion and prevent sediment from entering the Neversink River, which flows directly past the property.

Often, operators outsource stormwater management work and the associated permitting and BMP designs to engineering firms. But as Taylor and his staff at Holiday Mountain have learned, an in-house understanding of stormwater management can be beneficial for cost savings and preventing worsening issues.

Maintaining Pre-development Hydrology

As land is developed, whether for a ski area, shopping mall, housing development, or another project, the overarching goal is to utilize a network of structural BMPs to maintain the site’s pre-development hydrology, avoiding erosion and sediment discharge into natural waterways. At ski areas, where steep slopes and snowmelt are the norm, stormwater management is especially important. This has become increasingly apparent in recent years, when high-intensity rain storms and consequent flooding have become more frequent.

Working with the land. At Maine’s Saddleback Mountain, which was shuttered from 2015 until 2020, the operations team works with the natural topography to achieve this goal. “Mother Nature will tell us what she wants to do and how she wants to do it in terms of water runoff on the hill,” says Jared Emerson, Saddleback’s director of mountain operations. “We can help Mother Nature succeed in handling the most water possible without eroding [the soil]—basically maintaining what she’s already decided she wants to do.”

Preventing watershed contamination. But erosion is just one piece of the puzzle. Implementing the appropriate BMPs also ensures the water quality in local watersheds is maintained to the highest standards. Regulations and guidelines are set at the federal, state, and local levels to ensure that sediment discharge does not alter natural waterways, and that land is not destabilized through erosion.

Excessive runoff and sedimentation can increase filtering costs for drinking water, increase flood potential, degrade fish habitat, and cause downstream damage, according to the USDA Forest Service guidelines on “Ski Area BMPs.”

 Left to right: Motocross trails built by the previous owner resulted in severe flooding and erosion at Holiday Mountain that the new owner has worked to remediate with a variety of BMPs.

Types of Structural BMPs

Depending on the application, slope and soil types, land use, stormwater management goals, and future site development, resorts can implement a multitude of BMPs to help prevent erosion and protect watersheds.

Temporary construction BMPs. During construction, temporary BMPs are used to stabilize disturbed soil and control stormwater, erosion, and the movement of sediment while the unvegetated earth is exposed to the elements. “Temporary stormwater BMPs typically consist of features constructed more or less along the hillslope contour to stop or slow stormflow and catch sediment,” says Forest Service representative Wade Meuhlhof. 

Straw wattles and water bars are the most common temporary BMPs. Other options include hay bales, silt fencing, geotextiles and erosion control blankets, sandbag barriers, and check dams. Often, different construction phases require unique tactics to manage stormwater; the appropriate means must suit the surface conditions anticipated at each specific point in the project.

Long-term treatment BMPs. On-mountain BMPs typically aim to “slow stormflow and other runoff and redirect it from the fall line and away from locations where sediment may be dumped directly into streams,” says Meuhlhof. Measures consist of things like water bars, culverts, stone check dams, and swales to slow and redirect stormwater into wooded areas.

“The most common of these is a series of water bars with spacing dependent on the slope gradient,” Meuhlhof notes. “Angling drainage structures such that alternate water bars drain to opposite sides of the run also helps to minimize increases in streamflow along any one stream channel.” 

However, he adds, “Water bar presence, spacing, or maintenance are often insufficient at many mountain resorts, especially those that have not had major work done along their runs for many years.”

Around base areas, several long-term measures are possible. One typical choice is a riparian buffer, a natural or engineered space that lines waterways and is intended to filter runoff. Other options include grassed swales, infiltration basins and trenches (which allow stormwater to pool and seep into the ground), wet ponds (storage basins that contain permanent pools of water), and stormwater wetlands. All these can redirect and treat stormwater runoff before it’s discharged back into the watershed.

Surface vs. subsurface BMPs. While there are subsurface treatment BMPs—like underground chamber systems—that can be constructed under parking lots and other areas where above-ground space is limited, it’s typically cheaper and more practical to build surface BMPs, like treatment ponds, when there’s enough flat space for them. 

Promoting infiltration. According to Peter Smiar, director of land development and a professional engineer at VHB, infiltrative practices are preferable when site conditions allow.

“If you have sandy soils where water soaks in, it’s best to use a stormwater practice that also does that,” says Smiar. “Infiltration is beneficial because the runoff soaks back into the ground and doesn’t have to be managed further downstream. This replicates a natural situation where water soaks in, which is the goal of stormwater management.”

These infiltrative BMPs are designed to slowly filter and infiltrate water into the ground using a combination of soil, stone, and plants. Such systems can consist of stone trenches, grassed basins, or bioretention systems that have a layer of planting soils and are often densely planted.

 Arapahoe Basin used BMPs to restore streams and wetlands near the Wrangler trail (left) at the old Norway lift (right).

Filtration and Infiltration

Infiltration isn’t always practical at ski areas, where the subsurface often consists of impermeable ledges and compacted soils, or where the water table is high. “Its feasibility in areas such as the Rocky Mountains may be spotty, given the typically thin layers of soil atop bedrock in many areas,” says Meuhlhof.

Under-drained systems. “[Infiltrative practices] are probably the best treatment out there,” says Smiar. “But if you can’t [utilize] those because of heavy soils or a high water table, which is often the case at least at East Coast ski areas, then you get into systems that are under-drained. You still have plants and soil, but the water is slowly released through a drain pipe in the bottom.” 

Gravel wetland systems, for example, are constructed wetlands with a gravel base covered in a thin layer of soil and plants that remove sediment and nutrients before slowly releasing the treated water.

Wet ponds. Some surface BMPs that don’t rely on infiltration, like the wet ponds at Stratton, Vt., use a vertical standpipe with holes that allow treated water to drain as the level increases.

According to Smiar, while wet ponds and other BMPs that rely on settling are often simpler and cheaper, they’re becoming less common in Vermont and some other states due to newer state requirements preferring filtration or infiltration systems.

In fact, Vermont issued a “Three Acre Stormwater General Permit” to certain areas of the state in 2020, requiring applicable landowners with three or more acres of impervious surfaces to upgrade or construct BMPs to comply with “modern” standards in an attempt to lower phosphorus levels in Lake Champlain. To comply with these standards, infiltrative BMPs must be utilized, unless it can be shown that they aren’t feasible, in which case the owner can then utilize a filtering BMP, like a submerged gravel wetland, or non-structural BMP, which includes measures like erosion control planning or stormwater trainings.

Pre-treatment. Most treatment BMPs are constructed alongside pre-treatment BMPs that allow sediment to filter out before entering the larger system. Often, these are sediment forebays or smaller ponds intended to trap and settle sediment before discharging through a stone “check dam” into the main BMP or vegetated filter strips that slow and filter runoff upstream of the BMP.

BMP Maintenance

Most BMPs require some level of maintenance. “At resorts or portions of resorts where ground-disturbing activity has been limited over the years, BMPs are often in need of maintenance and upgrading. Resorts benefit from using an adaptive management approach to runoff and erosion: if existing measures are insufficient, they should be improved to protect natural resources and minimize impacts to infrastructure downslope,” Meuhlhof says.

To that end, a system of pre-treatment and treatment BMPs ensures the highest quality of water is discharged into the watershed and often reduces maintenance costs.

Holding ponds. “We have systems that include ditches, stone-lined swales, and grass-lined swales that all feed into a holding pond,” says Jeff Cavagnino, Stratton’s senior mountain operations manager. “Some of our ponds have forebays, which makes maintenance a little easier. You don’t have to dredge the entire pond every couple years.”

Cavagnino has found that bringing in a vacuum truck for a few days annually or bi-annually to pump out the forebays is much easier than having to deal with cleaning the entire pond. “Sometimes if you let it get away, you’ll have to bring in bigger equipment to maintain the BMPs properly,” he says.

Additional BMP maintenance includes cutting brush and keeping everything free of debris—an ongoing task that costs Stratton tens of thousands of dollars each year.

Wattles and silt fences. Meuhlhof notes several potential issues to watch for. Straw wattles and silt fences, two of the most commonly-used temporary BMPs, can leave debris behind. Forests in the Rockies, he says, are “increasingly banning the use of straw bales, wattles, or mulch due to the common occurrence of weeds appearing even in straw that has been certified as weed-free.”

Silt fences, he notes, “commonly fill with sediment, or get knocked down, and fail to work properly unless regularly monitored.” Sediment should be removed from silt fences and wattles to keep them functional.

“The best system in areas near water bodies with gentle slopes may be a combination of wattle and silt fence, each helping to protect the other from failing,” he concludes.

A nine-person team maintains and manages Jay Peak’s BMPs. Here, team members repair the liner (left) and add new stone to a retention pond.

Staffing for control. Jay Peak, Vt., which maintains stormwater systems for 51 acres of impermeable surface, keeps a full-time, year-round stormwater crew of nine people to maintain and manage its BMPs, including one person who files for permits, completes reports, and serves as a liaison between the resort and engineers. Having a crew to keep up with these systems ensures that inspections, which are done by licensed engineers every few years, go smoothly and maintenance costs are kept to a minimum.

According to Jay Peak director of facilities Andy Stenger, keeping these operation and maintenance tasks in-house likely saves the resort nearly $200,000 annually.

Plowing snow. A key component that’s often overlooked at ski areas, and is part of properly maintaining structural BMPs, is the basic task of properly managing snow plowing on access roads and parking areas. Operations teams at ski areas tend to push snow, gravel, and sand from parking lots into swales and treatment ponds, rendering them less effective and requiring them to be cleaned sooner than would otherwise be necessary.

Planning for the future. Operators can save money in the long run, if they have the space and budget, by planning for anticipated improvements. This often means overdesigning stormwater BMPs for current projects so the BMPs are able to handle water from the addition of impermeable surfaces in the future.

“When talking about downstream conveyances such as channels or culverts, it is best to size those for anticipated full buildout,” says Smiar. “The more complex these treatment systems become, the more challenging it can be to excavate and expand them later.”

The Forest Service may increase its requirements for BMPs in the next few years. “The Forest Service Rocky Mountain Region is in the process of creating a comprehensive package of recommended BMPs for mountain resorts, which in the future may be incorporated in total or in part by individual national forests as part of their resource management plans,” says Meuhlhof. 

“If this occurs, this will essentially have the same status as a federal regulation for actions occurring within that forest.

“This set of BMPs and project design criteria (PDC) covers everything from standard BMPs along ski runs and roads to wetland protection, stream health, road decommissioning, mulching, revegetation, and out-year monitoring.” 

Investing in natural resources. Unlike other resort expenses—like terrain expansions, lift upgrades, and routine operation—stormwater management and BMP upkeep is an expense without a direct return on investment. But these investments help avoid potential environmental disasters that will impact operations and preserve the land skiers and riders recreate on.

“We love our mountains, the property, and the surrounding beauty so much,” says Saddleback’s Emerson. “And if we’re not being responsible with how we’re managing erosion and runoff, we’re doing it and ourselves a disservice. It’s a headache and a cost and a pain sometimes, but it’s our responsibility to maintain the beauty of this place because it’s pretty special.”

SAMMY Guest Editor says…

I was on site to support the cleanup at Sunday River, Maine, in December 2023 after several inches of rain fell in a short amount of time and left the resort with major flood damage. Standing both on the sidelines but also on the field directly, it seems the storms we are experiencing today are stronger than ever. These storms are distributing a lot of rain in noticeably short periods of time. These occurrences are happening more often it seems, and in recent years, we have seen storm destruction in many states—not only in the Northeast and Midwest, but just about everywhere.

It is important with all construction projects to have a proper stormwater mitigation program. The mitigation plans for construction projects will likely include silt fence, water bars, wattles, etc. These are not “set and forget” items. They will require weekly checks and will need more attention after a weather event. Strong winds can displace silt fence. Water flows can carry silt that must be cleaned out of these devices so they can perform at their best for the next storm.

It is also important to create a management plan for your resort property. Existing streams that zigzag our resorts eventually cross our ski trails. Culverts are a good choice to manage these, but rock-lined ditches can do the job as well. These methods may be able to handle a higher water volume, but like any water management device, care and maintenance is essential. Have a post-storm management plan to inspect all culverts, catch basins, and retaining ponds, ensuring they are all free of debris and silt. Culverts get blocked, ponds fill with silt, and intake overflow pipes get clogged with vegetation. 

Stormwater management should be a top priority for the operations teams throughout the spring, summer, and fall seasons. Following a routine program could help mitigate the flood destruction at your resort. Even with all the preventative measures you take, though, recognize that Mother Nature may still prevail.

—Jeremy Cooper, VP of Mountain Sports Development, Boyne Resorts

2024 SAMMY Leadership Award Honoree