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Protecting Existing Vegetation during Construction

Compaction and Root-clipping are the Enemy

protecting trees from the bulldozerThe bulldozer operator and the construction foreman don’t always sit down and have a frank discussion about the special care needed to avoid damaging existing vegetation. What kind of personality would you expect from someone who drives a bulldozer for a living? Think about that for just a brief moment.

Now you see why it is so important to require orange protective fencing to be place at the drip line boundary of any tree you want to preserve during construction demolition. Pushing over a tree is not the only danger. Bulldozer operators like to, understandably, park their heavy equipment in a nice, shady spot when it is not in use. It only takes a few passes under a tree with a regular passenger vehicle to compact the soil to 95%. Imagine the effect of a piece of equipment that might buckle a typical driveway pavement surface!

Sturdy orange protective fencing is the visual clue needed to help the clearing contractor understand the limits for his heavy equipment. Locate it beyond the drip line of any tree you are trying to save.

Restoration of Complex Water Systems

Know Your Limits

complex stream restoration

How complicated is the impacted water system you have been tasked to repair? Should construction designs be creating projects that move rivers or impact large natural water systems where bulkheads and seawalls and gabions are needed? Before your project begins, ask if the new development can be relocated to avoid disturbing a complex water system. Or, when impacts cannot be avoided, research if enough land or right of way can be purchased to allow for gentle and reasonable mitigation solutions rather than huge walls and massive stone mattresses. If you are asked to provide mitigation for a river or an intricate waterfall, then it is a good time to stop and evaluate your capabilities.

If the impact is unavoidable, then the job may have overwhelming physical obstacles. It is wise to call in experienced civil engineers and a design firm that specializes in huge, complex projects of this nature. They need to be willing to visit the site. Large water volumes and both surface and subsurface grade changes are involved. Sometimes it is wise, as a designer, to walk away from a project. Not everyone is good at this, and the consequences can be catastrophic if handled casually.

You can proceed confidently with smaller mitigation projects that require only vegetative planting, as long as you receive good guidance from experienced restoration experts.  Whenever we, as designers, have control over how grading for development takes place, we should make every effort to design new contours that can be established easily with native plant material, without the need for structural marvels of engineering. Using vegetation to mitigate stream impacts is the preferred method, and the least expensive.

The agencies to which you submit mitigation design proposals will review your work, but you are the ultimate responsible party for your design, with all the liability that comes with it. Get help if you think you need it.

Scope of Services

Speak Up Early in the Process

scope of services for restoration plantingThere is almost always a tight timeline for environmental mitigation landscape for a project, even when the need for landscape work is known years in advance. It is something left to the last minute.  It is the last item on the checklist. I wonder if most people focus their attention and efforts on the hardscape construction because the majority of the budget is being used for structural features. Maybe it’s because the primary goal of most projects is building infrastructure, and the mitigation part is just an annoying requirement. In team meetings, there is a deliberate effort to not appear too environmentally centered for fear of seeming frivolous. For road construction projects, the roadside landscape is certainly a second-class concern on the schedule.

It isn’t fair, but attitudes are not going to change any time soon. That is why environmental commitments have been written into law—to require agencies and construction companies to do the right thing. There was neglect and abuse before the laws were passed. The laws indicate the intent of the populace. It is clear the public wants construction to be responsible and considerate. They want stable soils that don’t wash into streams. They want protection of estuaries and marshes. They want pollutants reduced and contained. They want fresh air and clean water, even if it means slowing down important construction and infrastructure projects. If you are using taxpayer funding for your project, you have been given a stewardship mandate that must be integral to the project’s development.

Getting the Team Together

Establishing Mitigation Project Protocol 

restoration team goalsThe first thing everyone involved in a stream or wetland mitigation project should do is establish the project goals. The initial meeting invitation should include a specific request for a list of goals. You need the project manager, the engineer, the hydrology expert, the contract enforcement monitor, the regulatory officials, and the ecology specialist in the same room at least once to establish this. Be sure to include the landscape architect and pragmatic plant experts in this meeting! It will save huge amounts of mitigation money later.

Once in the meeting, the vegetative mitigation plan designer should speak up when the conversation turns to planting restoration. Ask about the available budget, the maximum slopes allowed, the needed land purchases required, responsibilities for design plans, installation monitoring, plant maintenance, scheduling deadlines, and specifications needed.

A commitment to keep everyone in the loop during the project progression is important, with a clear Project Manager as the communication touchstone for all activity. Emails and documents should include the unique project number, to avoid confusion. Review comments can steer the project from potential pitfalls. Establish reviews throughout the design phase—concept, preliminary, final, and whenever edits are made to the plans. Pass around copies of a sign in sheet in review meetings, with contact information distributed at the end of the meeting. Review meetings are a good time to get to know everybody in other disciplines and establish good working relationships.

Reflections on the History of Restoration Projects

 

Analyzing Mitigation Success

The history for mitigation success has not always been good. Granted, we are all relatively new to this. Sometimes the failures are due to simple environmental variability—idiopathic dieback, storms, mechanical damage, or sea level rise. Sometimes restoration ends up being more successful by leaving it to grow back on its own! That is not always the case. Waiting up to a decade for a disturbed site to regenerate falls short of the objectives set by regulatory agencies and leaves a damaged site in less than optimal conditions for too long. The solution needs to be something that can fix disturbances quickly. We’re learning as we go. Here are some common, hard-learned lessons for restoration projects.

• Steep slopes guarantee failure.

• Designers need to visit the site in order to understand what must be done to restore it after construction.

• Surface drainage needs to be formed through sensitive grading that accommodates multiple lateral connections to the disturbed streams. Drainage needs to mimic a local, natural system.

Roadside Stream Buffers and State Waters

wildflowers at concrete ditchRoadside Stream Buffers and State Waters

A lot of times, streams run near the road. Also, drainage ditches run parallel to the road pavement. Anytime there is a base flow or containment of storm water on the rights of way, it is considered a protected state water. That flow can be only intermittent, and sometimes the only way of telling if base flow exists is by the presence of indicator plant material. Nevertheless, these areas and the wide buffers just beyond the water line need to be protected. That means, for most warm-water streams, you cannot remove or disturb any existing vegetation for a minimum of 25 above the water line on either side of a stream without a special variance from the Environmental Protection Agency. In cool water trout streams the buffer extends to 50 feet on either side of the water line. Wetlands, marshes, and sediment basins have buffers, too. When water is involved, regulations are involved. Along with EPA protection requirements, metropolitan areas also have compliance regulations for MS4 permitting, the Municipal Separate Strom Sewer Systems. It provides for methods to prevent discharge of pollutants into waters of the United States. All of this falls under the NPDES (National Pollutant Discharge Elimination System) permitting program.

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