Gary LoRusso Pioneers Low-Impact Drainage For Cold Climates - See more at: http://westernjournal.com/gary-lorusso-low-impact-drainage/#sthash.ldHyG45s.dpuf

 

 

“It has to work when the mid-winter thaw comes and melts months worth of snow in a day or two,” says Gary LoRusso, a Palmer, Alaska-based licensed land surveyor who is heavily involved in the land development business. As a surveyor in the land development arena, Gary LoRusso has been tasked with keeping silt-laden storm water originating from developments from traveling off-site and into area waterways.

“I have always been working towards protecting the environment while creating developments that allow people to enjoy living the Alaskan dream. The problems associated with storm water run-off affect the quality of life for all Alaskans. Not being the kind of person to wait for someone else to possibly come up with a solution to the storm water issue, I decided to come up with my own design” says Gary LoRusso.

Storm-water runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces and does not percolate into the ground. As the runoff flows over the land or impervious surfaces (paved streets, parking lots and building rooftops), it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff is discharged untreated.

The primary method to control storm-water discharges is the use of best management practices (BMPs). “The problem with the existing BMPs is that they were mostly designed for use in the lower 48 states,” says LoRusso. “The Alaskan climate presents unique challenges to the land developer, who is required by law to deal with storm-water generated from human activities,” LoRusso states.

According to the EPA, “the storm-water pollution problem has two main components: the increased volume and rate of runoff from impervious surfaces and the concentration of pollutants in the runoff. Both components are directly related to development in urban and urbanizing areas. Together, these components cause changes in hydrology and water quality that result in a variety of problems, including habitat modification and loss, increased flooding, decreased aquatic biological diversity, and increased sedimentation and erosion.”

“Effective management of storm-water runoff offers a multitude of possible benefits,” notes the EPA, “including protection of wetlands and aquatic ecosystems, improved quality of receiving water bodies, conservation of water resources, protection of public health and flood control.”

The run-off from the types of developments that Gary LoRusso designs is mainly limited to water draining from residential projects into roadside ditches and culverts. This run-off has traditionally been handled by channeling it into ditches to be transported off-site. The problem with this traditional design is that it does not de-silt or de-contaminate the storm water before it enters natural water bodies.

With the current EPA storm water regulations this old method is no longer a viable option.

In the lower 48 states, the issue is being dealt with through the creation of bio-swales and retention areas. This approach works well in areas in which the ground is not an impervious frozen surface that is as hard and impenetrable as concrete.

“In this part of Alaska, most of our problem run-off is generated in our annual mid-winter thaw,” notes LoRusso. The problem then is twofold: first, there is a large volume of silt laden and contaminated water generated from months’ worth of snowfall that has been concentrated by snow plowing activities. Second, the ground is frozen rock hard, so the runoff from the melting snow and ice cannot filter through the ground and self-clean before entering natural water courses. It rushes down the sides of roadways in torrents, eventually finding its way into streams packed full of its burden of silts and contaminates.

Gary LoRusso needed a solution.

“I thought about this for a while,” LoRusso explains. By combining existing methods and devising some new ones, he believes that he has come up with a solution that works in frozen ground conditions. Has used this method on various projects in his area and it, and variations of it have become the standard for development in his area.

Gary Lorusso Explains New Runoff Management Approaches

“The first thing that I needed to do was to change the way that roadside ditches are constructed. The traditional outdated idea of using the ditch solely for a conveyance system needed to come to an end,” Gary LoRusso explains.

The roadside ditch needed to be flattened so that the runoff water could be slowed down, spread out and soaked in before it entered ground infiltration structures that LoRusso would design. The flatter ditches allowed for water infiltration during the growing season and had a few added benefits that LoRusso was to discover.

In a typical development with roadside ditches, the homeowners would landscape up to “their side” of the ditch. This left an ugly un-maintained strip along the entire roadway. What has occurred with the flatter ditches is that homeowners will now landscape right up to the edge of the paved surface, creating a manicured look throughout the project as opposed to the unkempt look that is common in conventionally-designed developments.

The traditional ditching method created a safety problem on two fronts. The ditches are 3 feet or more deep, and when they fill up with water, there is a danger of children drowning in the ditch. The other safety issue is that the ditches left nowhere for pedestrians to get off the road when vehicles approach as the ditch sides are too steep.

With the flatter ditches, there is no danger of water pooling deeply enough to be an issue, and because the sides are so flat, there is lots of room for pedestrians to safely move out of the way of oncoming traffic.

As LoRusso goes on to say, “What we have seen is that this flat-ditch design creates a pedestrian-friendly development. There is room for visitors to park along the road without blocking the driving lanes, and now people can safely travel on the roads without the fear of pedestrian/automobile conflict.”

The next task facing LoRusso was to design a storm water infiltration structure that would function during the mid-winter thaw, or at any time when frozen ground conditions exist. He came up with a design that is cost effective, easy to install and easy to maintain.

This system allows for water to travel down the new flatter ditches into these infiltration areas, de-silt before infiltrating and then filter through the ground, re-charging the aquifer and eliminating the surface runoff that was degrading the water quality in the area stream and rivers. This design is not limited by frozen ground, and the only feature visible above ground is a manhole cover which makes for a more aesthetically-pleasing and functional development.

 

LoRusso continued, “You can see by my design that most of the system is underground where the warmth of the earth, though slight, helps to keep it thawed. Since there are plenty of air spaces around the 4” – 8” rocks, any storm water that enters the chamber will filter into the surrounding ground, re-charging the aquifer and cleaning the water in the process. Leaves and grass won’t plug the system because the grated manhole lid is higher than the surrounding area, yet it is set lower that the road surface. This allows water to collect and de-silt before entering the system. We use driveways and other developmental features to create a block forcing water to channel to the infiltration chamber. The chambers themselves are set every 300 feet or so along the roadways, approximately the same distance that you would see a conventional storm drain grate in a city street.”

But people and government agencies are not always fast to change, and may be slow to accept new and better ideas. “The first time we used this system locally in a development, it was a tough sell to the governing Public Works Department in Palmer because it wasn’t constructed in the way they had always done it,” explains Gary LoRusso. “We had assistance from the local branch of the EPA, and now the local Public Works Department sees the wisdom in the design.”

As his list of successful developments increases, we will be seeing more and more of this design in and around LoRusso’s home town of Palmer, Alaska, where he is very happy to be doing his part in creating livable communities that have as small an impact on the local environment as they can.

“There is always room for improvement, and with each new development we learn from past mistakes and past successes,” Gary LoRusso affirms.

 

 

 

 

 

 

ABOUT:

Gary LoRusso is a licensed land surveyor based in Palmer, Alaska. In pioneering effective methods of managing runoff, LoRusso contributes to the maintenance of healthy environments and vibrant communities.

- See more at: http://westernjournal.com/gary-lorusso-low-impact-drainage/#sthash.yJswtzDY.dpuf