Tag: Environmental Protection

Landslides: Prevention & Repair Through Slope Stabilization

Slope failure photo with blog title

In New England, March marks the last weeks of winter and the start of spring rains and snow melt.  Paying attention to erosion control during this time of year is always on the minds of municipal public works staff, state agencies, construction companies, and even homeowners, especially those fortunate enough (or perhaps not) to have water frontage. 

A 2018 study conducted by the USDA found that precipitation is increasing in the northeast more than any other region in the United States. The frequency of consecutive wet days is generally increasing in the northeast and precipitation extremes have also become more frequent. Given these trends, it is no surprise that peak flows in rivers and streams are also increasing and occurring earlier in the year which can result in a greater risk of flooding.

While it is difficult to prevent major erosion of stream and river banks due to extreme precipitation events, damage can be mitigated by inspections of at-risk areas combined with prioritization of these areas for repair. It is important to address slope failures quickly because bank degradation can cause significant damage including loss of property and infrastructure, sedimentation of the waterbody, water quality issues and damage to critical riparian buffer areas. As civil engineers, we can provide assistance with erosion control issues that range from preventative design practices, culvert replacements and stabilization of failed embankments.

Below is a list of some stabilization practices along with before and after photos of our recent embankment stabilization projects.

One such embankment failure occurred in Lancaster, New Hampshire, when high flow conditions in the Connecticut River resulted in severe washouts along an 800 foot long embankment causing loss of land and unstable soil conditions. Hoyle, Tanner designed and permitted solutions to repair and stabilize the slope using native riparian vegetation and rip rap armament. Live willow and dogwood stakes were planted in soil between the rip rap stones.

Terms to know:

  • Live willow & dogwood stakes: Living shrub cuttings that take root quickly in bank environments – provides natural habitat and additional erosion control
  • Rip rap: Large stones used for protection and dissipation of energy from high water flows
Washout along the Connecticut River in Lancaster
Lancaster Embankment after Stabilization

Hoyle, Tanner also designed and permitted repairs to a steep slope in Rochester, Vermont, when intense rainfall events undermined the toe of the bank, causing the slope and roadway above to fail and slide into Brandon Brook 90 feet below.  The repair solutions included installation of a blast rock toe detail and stone facing with grubbing material along the hillside to restore the slope. The roadway was reconstructed and a mid-slope underdrain was installed to intercept groundwater seepage. Debris from the slope failure was removed from Brandon Brook and the streambed was restored.

Terms to know:

  • Stone facing with grubbings: Combination of stone and native material to promote vegetation growth
  • Blast rock toe: Large rocks placed at the toe of the re-stabilized slope to combat undermining
Rochester Slope Failure at Brandon Brook
Brandon Brook Stabilized Slope Repair

Improving safety and combatting damage from growing peak flows and extreme storm events is an important part of our job. Hoyle, Tanner is excited to offer solutions to slope stability issues and challenging site conditions. For more information on how we can be of assistance, please contact me.

Presidential Power Sways Environmental Perception

Who would you say was one of the most significant environmental Presidents? Would it surprise you if I told you I think it is Richard Nixon? Yes, the only US President to resign from office, and who commonly made such un-eco-friendly statements as comparing environmentalists to a bunch of animals, was also the President who signed into creation the National Environmental Policy Act (NEPA) in 1969. This was one of the first laws that established the legislative framework for protecting the environment, outlined national environmental policies and goals, and developed the Presidential Council on Environment (now known as the Council on Environmental Quality (CEQ)) within the executive office. NEPA requires federal agencies to integrate our national environmental values into their decision making processes by considering the environmental, human and social impacts of their proposed actions as well as the reasonable alternatives to those actions.

In 1970, President Nixon also created the Environmental Protection Agency (EPA). Before the agency was created, our nation had no central authority overseeing the protection of the environment. Shortly afterwards, he signed into effect the Clean Air Act Extension. This is one of the most significant air pollution control bills in American history. It required the newly formed EPA to create and enforce regulations to protect people from airborne pollution known to be hazardous to human health, specifically targeting sulfur dioxide, nitrogen dioxide, particulate matter, carbon monoxide, ozone and lead.

President Nixon also signed into effect the Endangered Species Act (1973) creating the concept of preserving species and their habitats listed as threatened and endangered; this act has been called “the Magna Carta of the environmental movement.”

Finally, in the midst of his impeachment concerns, Nixon also proposed and lobbied through Congress the Safe Drinking Water Act that was ultimately signed by President Gerald Ford in 1974. This act initiated national efforts to protect the nation’s lakes, streams, rivers, wetlands and other bodies of water. It is fundamental in protecting aquatic resources including public drinking water supplies.

It comes as no surprise that during such an important environmental awareness period the first Earth Day was celebrated on April 22, 1970. Earth Day founder Gaylord Nelson, then a U.S. Senator from Wisconsin, proposed the idea of a “national teach-in on the environment” to the national media and ultimately gathered a national staff of 85 to promote events across the country. On that first Earth Day over 20 million Americans took to the streets, parks, and auditoriums to demonstrate for a healthy, sustainable environment in many wonderfully creative ways.

In the 45 years since the origin of NEPA and these other ground-breaking legislations, environmental protection and regulation has become extensive and complex. In my role as Environmental Coordinator, I work hard to ensure our clients and projects comply with the applicable laws and regulations that govern our projects. I work to guide projects from preliminary design through construction and operation while successfully acquiring the relevant federal and state environmental permits, including NEPA compliance for impacts to streams, rivers, floodplains, wetlands, and state- and federally-listed species, among others.

Earth Day 2015 will celebrate the 45th anniversary of the event that raised environmental issues awareness to unprecedented heights and brought the concept of working towards a cleaner and safer nation from a wild “hippie” idea to mainstream citizens. For more information on how you can participate in Earth Day celebrations and events visit Earth Day Network.