About excavation
by Frank Vogler

Green building is all the rage in many parts of the country, including our own, however, a major component of the construction process has remained virtually unchanged and unnoticed, excavation. Excavation goes by many names, including grading, dirtwork, site prep, earth moving etc., but essentially boils down to the practice of altering the natural shape of the land to suit human desires and pursuits.

Excavation is by nature destructive. Its adverse impacts upon our fragile bioregion, including erosion and sedimentation, have been severe and long-term, especially with regard to our soil fertility, view shed, mountain waterways and wetlands. Excavation has also had a hand in unleashing the plague of invasive flora rapidly becoming naturalized in the Appalachian Mountains. Equipment undercarriage packed with soil and seed matter moved from site to site literally plants invasive species. So common is the damage caused, in large part, by excavation that many now simply assume muddy rivers, giant swaths of bare subsoil and banks of kudzu, mimosa and miscanthas grass are normal.

In 1973, in response to growing concerns about environmental degradation caused by land disturbing activities, the North Carolina Sedimentation Pollution Control Act was created. This act, while maintaining some generous and controversial exemptions for mining, forestry and agriculture, set basic requirements for land disturbing activities, (i.e. excavation), provided enforcement authority to the North Carolina Department of Environment and Natural Resources (DENR) and Division of Water Quality (DWQ) and established civil penalties for violations.

The basics of the law are this:

For areas larger than one acre an erosion and sediment control plan must be approved before any grading can occur. (Many municipal districts now have stricter requirements.)
Surfaces on the construction site must be stabilized.
Sediment must be retained on site.

In addition, specific guidelines were established for individual practices such as stream buffer creation, cut and fill slope angles, inlet protection and re-vegetation. Despite these long-standing rules, and many recent amendments, such as the NC Wetlands Standards, the situation is still bleak. As biologist Shae Tuberty of Appalachian State points out, the number one pollutant in most mountainous regions is sediment, not coal ash, mercury or trash.

It comes as no surprise to anyone that development activity has increased markedly in the last three decades. Some counties, such as Mecklenburg (which includes Charlotte), have been transformed into entirely metropolitan areas. Enforcement is somewhat lacking due largely to funding. Many contractors and excavators have not received specific training and don’t know how to properly install and/or maintain erosion and sediment control measures associated with excavating. Finally, Climate Change with its attendant weather extremes is placing a greater burden upon those engaged in earth moving to improve both their skills and protocols. As Tuberty points out, the increase in severe events will cause greater chances of 100 or 500 year floods – not something that common BMPs (Best Management Practices) can handle.

With such a large migration of folks moving from urban areas to our rural mountains, it is now imperative to reach out to the public to broaden awareness surrounding this issue.
It is natural that most urbanites are “house-centric”, tending to think less about their land than their dwelling, ironically one of the least permanent things on it. Consequently they usually under-budget for excavation related activities such as driveways, retaining structures, drainage features, landscaping, etc. Builders, appealing to the demands of their clients, follow suit and do the same. The cost borne by the indigenous inhabitants of our region, from brook trout to soil microbes, as well as homeowners and taxpayers, are enormous.

For instance, the cost of maintaining a poorly installed driveway (one that is too steep, lacks good visibility, appropriate drainage, surfacing, compaction, or any number of other necessities), is often more than the initial construction cost. Often a poorly placed and/or constructed driveway cannot be satisfactorily fixed and becomes a constant headache and resale issue for the homeowner or developer, as well as, by virtue of economic and environmental impacts, the county and state. Sevier County, just across the Smokies in Tennessee, was recently forced to completely restructure its land use and building statutes in response to development pressures in Gatlinburg, Dollywood and Pigeon Forge. Sadly, the damage to the unique Appalachian environment has already been done.

It is essential that homeowners, developers and builders think more clearly about access when siting homes and subdividing acreage. Lots are typically divided and sold solely according to their proximity to viewscapes and waterways, often without much thought about how to get there. According to one official I spoke with during a continuing education course, half of all stream sedimentation in WNC is caused by badly sited or installed residential driveways. He further pointed out that large commercial developers, due in part to big budgets, better engineering, and greater public scrutiny, tend to cause far less impact than small residential contractors.

On one site I visited in 2009, my prospective clients shamelessly drove me through a headwater stream, a native trout water, up a steep, un-surfaced and deeply rutted road bed to their chosen home site. They had refused to install any drainage features along the road in order to avoid damaging more trees. We parked on a completely bare knoll at the top of their property where they excitedly explained how their new home would be constructed of recycled, “on-site” and locally certified green materials, would be powered by photovoltaic panels and heated hydronically. Clearly their hearts were in the right place but education was lacking.

So what can be done? First homeowners need to understand more clearly the financial and environmental impacts excavation decisions will have on their future lives and take greater interest. Avoiding lots and acreage with physical access problems is one form of understanding, one that has direct market influence. In addition, homeowners must learn more about excavation practices, beginning with hydrology. Hydrology, simply put, is the study of how water moves. If you don’t have a clear account of where the water (all of it) is going to go after you or your contractor excavates, you have not completed your homework. Just looking back on the damage resulting from hydrology related issues in very wet 2009, including dozens of road and bank collapses, is shocking. My small company alone evaluated numerous sites where mitigation procedures totaled between 20 and 100 thousand dollars. One such fix nearly exceeded the value of the home.

In addition, it pays to know a little about soil complexes and compaction. Soil maps are available at no charge through the local county soil and water conservation agents (an office of the local USDA). Some soils in our area are highly erodible and unfit for some, if not all, excavation activities. In general, foundations and roadbeds must lie on virgin subsoil layers or clean compacted fill materials according to engineering specifications. These soils should be completely free of larger organic matter such as trees and stumps etc. Valuable top soils, those richer in organic matter, should be put carefully aside and reincorporated in finish grading procedures such as landscaping, and not discarded or mixed with fill materials.

Sound complicated? It’s really not. Like most things, once familiarity increases the facts begin to rapidly connect. One powerful way to bring all the information together is digital mapping, sometimes called rectified digital mapping. For rural landowners, as well as developers, there is no more valuable and inexpensive tool. A good mapping protocol incorporates multiple layers of data, from property boundaries and topographical contours to timber profiles and soil character. Well-prepared mapping sequences allow developers, contractors and homeowners alike to site homes, plan roads, organize timber harvests, restore pastures and wetlands, and more, with much less on-site data collection and guesswork. For instance, because the software allows the viewer to see an area in 3D, a relatively flat area can be digitally extrapolated to look like a mountain range if necessary to expose complicated drainage characteristics. (pics)

Mapping is to land planning what blue prints are to building. It is conceivable that in the future a good digital map will be as essential for common land transactions as a survey. I would no longer consider buying unimproved acreage without some form of digital mapping. Often I tell clients that a single mistake avoided through mapping more than pays for the procedure.

Another helpful strategy for those initiating excavation related activities is to DO LESS OF IT. This notion is an analogue of Amory Lovins idea of “negawatts”, or keeping track of energy NOT used as a benchmark. This means that whenever possible home-sites are selected based on how little excavating is required. Before the advent of hydraulically driven equipment this was largely how it was done in most parts of the world. It now makes more sense than ever, both environmentally and financially, to return to this common sense practice, which brings us to the issue of plan-book homes and design catalogs. It has become commonplace to purchase inexpensive house plans on line or through a developer and many prefer this to the more involved process of designing a home from scratch. It should be pointed out that many such homes require additional excavation procedures and consequently additional costs to make them fit a given sight. It would be a much better for all if we took to heart the wisdom of our most famous American architect Frank Lloyd Wright, “No house should ever be on a hill or on anything. It should be of the hill. Belonging to it. Hill and house should live together each the happier for the other.” A tremendous portion of a homes appeal is directly tied to how well it is integrated into the surrounding landscape. Somehow we have forgotten this simple fact and adopted the idea that a home can be made to fit anywhere, regardless of cost or materials. Whether we want to acknowledge it or not there are common sense limits to what excavation can accomplish in the Appalachian Mountains. Many subdivided lots and plans do not fall within these limits and this must change

Restrict grading activities to immediate building or road footprints. Grading outside these areas markedly increases environmental and financial costs, and works directly against many homeowners desire to have lush and natural yard spaces. There are much better options for creating recreational space and viewscapes, such as forestry mulching. Forestry mulching recycles unwanted biomass i.e. trees, shrubs, vines and other waste materials into mulch, on site, in a single step. Mulching can be very specific, leaving desirable native trees and other flora undisturbed in a manner far exceeding that of conventional heavy equipment. Because conventional heavy equipment removes the fragile upper topsoil layer, it is common for keeper trees left by bulldozers and excavators to die months or even years after the work has been finished. Mulching also vastly reduces erosion control costs, burning and hauling charges, soil compaction and fertility issues, as well as furnishing clean, tractable footing for building activities. (pic) Even successful hydro-seeding cannot withstand repeated heavy traffic.

Finally and perhaps most importantly, discuss excavation with your contractor or developer before you build or buy. I guarantee site prep and driveway construction are no small portion of your new home’s total cost. Furthermore, it has been my experience as a builder, that while folks deliberate endlessly over paint colors and bathroom fixtures, they disregard major site preparation and access issues under the assumption that the contractor knows what he is doing. Unfortunately, most contractors know a great deal more about construction than excavation. Most are basically relying on the skill of their subcontracted grading outfit as well as the drawings of an engineer or architect, the latter of which may not have an appreciation of the natural setting in which the construction will take place. As often as not these plans are incorrect and/or unspecific.

So, if your builder is subcontracting the excavation, get references and photographs of the subcontractor’s previous work and call those references. This includes getting older references. Usually mistakes, especially foundation and drainage issues responsible for cracking, shifting and slope collapses, take years to materialize, lessening the chance of remediation or compensation when they do. Likewise visit your excavator’s previous driveway jobs. A driveway completed in dry hot august will look quite a bit worse for wear by spring if improperly installed. Finally. Secure additional contractual guarantees against excavation related failures.

So again, for all those out there wanting to build sustainably, or just build period, extend your understanding and planning beyond the building itself. Think first about the land you are looking to buy or build upon. Don’t buy property with physical access issues. Take what is offered by your property in terms of contours, drainages, vegetation and soils. Consider digitally mapping your acreage if the terrain is not providing clear choices. Shrink your excavation footprint by employing forestry mulching for the creation of recreational space and viewscapes.
These are common sense steps toward both cost savings and good stewardship. Finally, educate yourself regarding excavation practices.

Sustainability is as much about following well-established protocols as it is about innovation, a motto for which might simply be “do it right, do it once”.

Frank Vogler is a partner in V & V Land Management and Resource Recovery LLC, promoting sustainable land-management practices in the Southeast. He believes that one of the biggest impacts you will have upon future generations are the decisions you make with regard to your land.