Tag: Environment

Using Ground Penetrating Radar to See What Lies Beneath the Surface


Beneath the Surface

Do you ever wonder about the history of the people who came before you and what remains they left behind that might be buried beneath your home, yard, or office? As part of project development, our staff has to think about this for every project to satisfy several federal and state requirements to protect those hidden resources. The National Historic Preservation Act (NHPA) was passed in 1966 to protect the Nation’s historical and cultural resources. Section 106 of the Act requires federal agencies to consider the effects on historic properties of projects they undertake – sometimes called a “Section 106 review.” For any project that requires a federal permit or uses federal funding, a completed Section 106 review is necessary to identify those crucial resources that may be affected by the project.

Federal funding for transportation projects within New Hampshire comes primarily through the NH Department of Transportation (NHDOT), which receives funding from the Federal Highway Administration (FHWA). Because of this, many of the projects that we work on require Section 106 review. The first step in this process is to identify the historic or cultural resources within the project’s work limits, which is also called the Area of Potential Effect (APE). This step includes those resources above-ground, such as homes, foundations, or structures that were built more than 50 years ago, and below-ground, such as remnants of prior human activity associated with both the Native American and European American periods. This is where we need an archaeologist’s assistance – enter thoughts of Indiana Jones!

Archaeologists are responsible for more than finding buried treasures, and their process begins with historic and environmental research followed by an archaeological survey of APE. This process is much tamer than what is shown on the big screen and involves less chasing and more research and excavation. (the professional term is excavation – gardeners dig, archaeologists excavate!) The first step is to check historic maps and records of what has been documented in APE; was there a town, house, settlement, camp, road? The site is also carefully examined to determine any clues to what may lie underground. Sometimes this can include a shovel test, which means excavating a small 0.5 meter/1.5 foot square area, obtaining soil information, and evaluating the level of historic soil disturbance. Once this information has been reviewed, if the site is determined to contain additional underground information, a plan is developed to complete further excavation across APE – more test pits, often within a grid pattern, to cover the areas to be impacted. While this method is the standard, any excavation can be a very disruptive and time-consuming process. Is there a better way to find buried evidence? Couldn’t we take a picture of what lies beneath, like an X-ray or ultrasound?

Seeing What Lies Beneath

Yes, we can! The idea of “seeing” using radio waves was first introduced in 1904 and was initially developed for locating ships at sea in storms, but was put to use on a larger scale in World War II to find aircraft that were too far away to be viewed by the eye. Using radar involves bouncing radio waves off the object from a distance and using the time the wave travels back to calculate distance. The term “radar” came from the US Navy in the 1940s as an acronym for Radio Detection And Ranging. Radar has many uses, including the police speed-detector guns you may have been unlucky enough to encounter. While the concept of bouncing radar waves underground to create a picture of what lies beneath our feet (or Ground Penetrating Radar (GPR)), was developed only six years after radar was first developed, the use wasn’t fully explored until the 1970s when the first affordable commercial equipment was developed.

GPR is now a widely-accepted tool that is used to identify a variety of underground features, such as:  utility lines and pipes, geological features such as large boulders, changes in the subsurface soil layers that may affect construction, or the depth to groundwater to develop wells for drinking water. GPR equipment looks a bit like a lawnmower and is rolled slowly across the survey area in a grid pattern (as seen below). The unit’s base sends an electromagnetic wave or pulse into the ground, and the echoes that bounce back are recorded using specialized software that translates these echoes into images of the objects in the subsurface.

GPR is ideal for supplementing underground archaeological surveys, primarily because the pictures that it creates can be used to identify features without the risk of damaging them that could occur during an excavation. This feature makes it an excellent tool for surveying areas where there is potential to find buried human remains. Cemeteries, graveyards and burial grounds might seem to be locations that would be well-documented (where did we bury Grandma, was it by the barn?); however, historical records can be lost, misplaced or damaged, or not recorded if the site was small. Even the oldest European settler burial ground in New Hampshire, the Old Odiorne Point Cemetery, located within Odiorne Point State Park grounds, has a complex history with scattered documentation regarding the location and number of burials.

Trivia: While the terms graveyard and cemetery both refer to a burial ground, graveyards are located on sacred or church grounds, while cemeteries are located on public or private grounds.

What We Saw

As part of the required Section 106 review for a project, Hoyle, Tanner recently worked with NHDOT in the Town of Conway to use GPR for investigating the Town’s first documented cemetery area, Meeting House Hill Cemetery, where the original Meeting House stood. Historic review completed for NHDOT in 1965 while constructing Route 302 indicated that this cemetery was used as early as 1740 to bury local settlers and included Revolutionary War soldiers. In the 19th century, the Town removed several sets of remains to other cemeteries in Conway to allow for road and railroad development in the area. Local information suggested that these areas were not thoroughly surveyed and that human remains could still be underground within the area.

Hoyle, Tanner worked with Independent Archaeological Consulting, LLC (IAC) to complete an archaeological investigation in the area around the cemetery marker using GPR. IAC contracted with Nearview, LLC to provide the highly specialized and hard-to-find GPR unit and conduct the survey. What does GPR look for? GPR imagery can show disturbed soil associated with a grave shaft, or echo reflections related to bones, coffins, grave goods, or clothes that would be different from the soil around these items. It can also locate changes in the soil layers that can be due to the digging from installing a grave – the mixing of soil when that happens creates reflections that differ from the surrounding area.

The GPR unit was rolled slowly across the ground in a grid pattern (like mowing your lawn, making sure you cover all of it!). Shovel test pits (STPs) were excavated in targeted locations to specifically intersect with GPR survey to check against any revealed soil anomalies or differences. While the GPR survey identified a single anomaly, the test pits excavated near the anomaly revealed soil layers that did not indicate the type of disturbance that would show the location of burial or human remains.

Eliminating this area as a location of unidentified burial spaces or human remains is valuable to the Town, its citizens and the families who have wondered for decades about this site. It also provided a timely and cost-effective process for NHDOT to clear this area of potential impacts to archaeological resources so that future roadway changes at the intersection of Route 302 and East Conway Road will not need to exclude this area.

GPR technology has come a long way since it was first developed, and we are excited to add it to our toolbox for Section 106 review. Using GPR can provide a better picture and give a definitive answer to what lies beneath. Find out more about GPR Technology by reaching out to me.

Your Holiday Decorations May Contain an Invasive Species

Decorating for the holidays can bring joy to households, and putting your decorations up early could make you happier, but watch out for Oriental bittersweet (Celastrus orbiculatus)! If you are a DIYer or like to craft your wreaths or other holiday decorations using materials from your backyard or local outdoor environment, you may be mistakenly causing harm to the environment and creating future landscaping challenges for yourself and neighbors. Oriental Bittersweet is covered with bright red fruits and yellow capsules, making this vine alluring, but according to the UNH Cooperative Extension service, the vine is also highly invasive and poses a significant threat to native plants.

Oriental bittersweet is native to Eastern Asia and was intentionally introduced to the United States in the mid-1800s as ornamental landscaping and for use in erosion control because it is both pretty and effective; it is fast-growing, spreads easily and is not finicky about soil or water conditions. Oriental bittersweet has escaped cultivation because it grows in full sun as well as shade, and in many different locations including meadows and grasslands, woods and woodland edges, along roadsides and even on dunes and beaches! After the invasive species made its way to New Hampshire in 1938, by the 1970s it was recognized as an aggressive invader, and by 2011 it was widespread across New England. It is now found throughout 21 of the 33 states where it was introduced, a region extending from Maine south to Georgia and west to Iowa.

Wherever Oriental bittersweet is found, it grows very rapidly, wrapping around trees, damaging, and sometimes suffocating or killing them. The vines can uplift tree roots and can take down trees that reach 90 feet in height. The extra weight on the trees can cause limbs to drop and contribute to power outages or cause damages.

Try American Bittersweet
When making holiday decorations or wreathes, a good alternative to Oriental bittersweet is American bittersweet (Celastrus scandens), but this species is less widespread in New Hampshire and is typically found only in landscaped locations actively maintained by a homeowner, since it cannot compete with Oriental bittersweet in areas that are not maintained such as roadsides and open wooded areas. The two species can be easily confused because they are similar in color and appearance. Oriental bittersweet fruit (pictured below) has a bright yellow outer covering with red centers, is located along the vines in leaf axils and has bright, yellow colored leaves in the fall that are easy to see. American bittersweet fruit (pictured below) can sometimes have a yellow outer covering but tends to be more orange or even red over a red interior and tend to cluster at the stem’s end.

Oriental bittersweet (left) and American bittersweet (right)

Winterberry

Try Winterberry
Another good decorative option that may be available locally is winterberry (Ilex verticillata) – this species (pictured right) is easily noticeable in the swamps, wetlands, damp wood edges, and along the edges of ponds and streams throughout New Hampshire. Showy, clustered red berries pop out from the vegetation in the late fall, and, different from bittersweet, persist on branches well into the winter months, explaining how winterberry got its name. It is often considered one of the best plants for providing winter interest in the garden.  

Ask for Help at Garden Centers
If you are cutting your own vegetation to use in holiday decorating, take the time to look further than roadsides, since those habitats tend to be invaded by Oriental bittersweet, or consider asking for scraps at garden centers or local nurseries since they may have remnant cuttings of native plants for free or low cost. Maybe even think about your holiday decorating in the summer and fall, so that while you walk, run, hike or explore your local surroundings, you can keep an eye out for winterberry, holly or American bittersweet locations. 

I Already Have Oriental Bittersweet – Now What?
Don’t worry, you can save the trees and your holiday spirit! If you see Oriental bittersweet in your holiday decorations, the best thing to do is throw it away. You can also burn it in your fireplace or woodstove. It’s best to avoid throwing it outside or composting since the fruit, or “berries” can survive through winter and will create new vines in the spring. If DIY isn’t your area of expertise, remember to ask when you purchase decorations with berries if they are real or plastic, and if they are real, where they came from, and does the seller know which species they are? Again, if you are ever unsure, best to throw them in a fire rather than outdoors to prevent the unintentional spread of invasive species.

Reach out to our Senior Environmental Coordinator Kimberly Peace if you’d like more information.

Endangered Species Day – Highlighting the Northern Long Eared Bat

Northern Long Eared Bat Photo

The United States has multiple federal laws and international treaties aimed to protect endangered species. Species conservation is a shared responsibility; our choices and actions are capable of making a difference for the better. As engineers, we at Hoyle, Tanner are committed to the protection of endangered and threatened species by working through strict permitting laws and utilizing environmental experts.

In 2015, the northern long eared bat received news coverage for becoming a threatened species under the Endangered Species Act (ESA). In 2016, it received a final 4(d) Rule, mandating that the species needs conservation help. Currently the main factor threatening these bats is a fungus called White Nose Syndrome, which is the disease responsible for a species decline of up to 99% in the Northeast.

Identifying the Northern Long Eared Bat

The northern long eared bat is a brown-toned, medium sized bat with a body length of 3 to 3.7 inches. Named for its unusually long ears in comparison to other bats, the northern long eared bat species range includes 37 states across most of the Eastern and Northern Central United States.

During the winter months, the bats can be found hibernating in caves and mines with constant temperatures, high humidity and limited air flow as hibernacula. In the summer, the northern long eared bats preside primarily in the crevices of dead trees. At dusk they feed on moths, flies, leafhoppers, caddisflies, and beetles. A hibernating bat with White Nose Syndrome can be identified by white fungus on its muzzle, causing the animal to act strangely and often flying out of their hibernacula during the winter months. White Nose Syndrome is currently present in 25 of 37 states within the species range and there are indications that it will continue to spread.

Protecting the Northern Long Eared Bat

White Nose Syndrome was first identified in New York in 2007 and has since been primarily responsible for the severe decline in species population. Steps in disease management have been taken by many government, non-government and university organizations to decrease the rate the disease is spread.

Since being listed as threatened on April 2, 2015, the northern long eared bat is federally protected under Section 7(a)(l) of the ESA, which requires federal agencies to use their authorities to conserve listed species. In June 2016, the Federal Highway, Railroad and Transit administrations completed a range wide consultation and conservation strategy for transportation construction and expansion projects. According to the article, “The programmatic biological opinion that resulted will help expedite the consultation process related to transportation projects and provide a consistent approach to conservation for the bats. The strategy includes:

  • Proactive conservation measures that are most suited and needed for the conservation of the species,
  • Priority areas for mitigation measures,
  • Standardized effects analyses with avoidance and minimization measures associated with project types,
  • An informal programmatic consultation covering all states; and
  • A limited formal programmatic consultation.”

For more information, visit U.S. Fish and Wildlife Services website.

How Can You Help?

We share the planet and the responsibility of being hospitable to other creatures. You don’t have to be an environmental specialist to help keep this disease from spreading. Here are a few things you can do:

Do Not Disturb: Cave and mine closures, advisories and regulations are there for a reason. Abide by them. By entering a cave or mine against security standards or recommendations, you could be risking the possibility of disturbing hibernating bats. Waking a hibernating bat can force it to use up valuable energy resources and in turn decrease its chances of surviving the winter. Furthermore, by entering a cave or mine without permission, you may be violating decontamination policies and exposing bats to White Nose Syndrome. Because we still do not know exactly how the disease is spread, you should never utilize clothing, footwear or equipment from an affected area in an unaffected area within the range

Save Dead Trees: A dead tree may be an eyesore compared to the rest of your beautiful yard, but before you cut it down, remember what could be depending on it for survival. Northern long eared bats are forest-dependent creatures that rely on different elements of forests to survive. By removing dead trees during a time when bats may be in the trees, you could be causing harm.

Build a Bat Box: Already cut the tree down? You can replace it with a bat box! By creating this backyard habitat, you are providing a safe and sound location for over 100 bats to roost. “Bat boxes are especially needed from April to August when females look for safe and quiet places to give birth and raise their pups.”

Tell Your Friends: Sometimes you can make the biggest impact by simply spreading the word. There are so many endangered species that need our protection and although a bat with unusually long ears isn’t as glamorous as a tiger or an elephant, it doesn’t make them any less important. Bats play a significant role in regulating the insect population and eliminating crop-destroying pests.

Many people do not understand the role they play in maintaining a healthy and balanced ecosystem. By spreading the word and telling people how they can do their part you will have a significant impact in the ongoing fight for the preservation of the northern long eared bat and endangered species as a whole.