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The Role of Landscape Architects

stream buffer violation, over clearing in a stream buffer

Success and failure—good restoration projects are nurtured by both. Experienced mitigation experts are born during the in-the-field challenges of vegetative restoration. Not all of these experts are landscape architects, but eco-restoration teams for projects large and small, benefit from a landscape architect’s perspective and participation. There are many different factors that contribute to a stable, dynamic equilibrium for stream channel sediment, and well-established native vegetation on the stream buffers is an essential part of that stability.

The professions that provide bioengineering expertise have become highly specialized, but still need to incorporate good horticulture, landscape design, engineering, and maintenance knowledge into a workable, sustainable landscape restoration plan. They need an experienced vegetative mitigation landscape designer on board. If you are new to this category of work, it pays to consult with seasoned professionals and get reviews and comments from them during the planning and design-drawing phases of the project. You need narrowly-focused professionals and designers as well as those who think about the big picture and field-experienced planners to make your eco-restoration team complete.

The following is a broad generalization, but it is based on experience reviewing many restoration project design proposals. A collaborative attitude comes naturally for landscape architects, but other experts might not be not wired that way. Landscape architects can remind the team members that each project is unique and cannot be treated in template fashion, with examples ready to prove the point.

Lead professionals on a restoration team might mistakenly think that the only role for a landscape architect is ornamental landscape design, and be reluctant to include an LA on the team, since aesthetic results are not the primary goal for a stream restoration project. It takes sophisticated planting plans to create a cohesive look that blends quietly into natural stream buffer vegetation, though. Landscape architects can help the team match readily available plant material with volunteers growing near the site. They can explain why pioneer species are essential, and how they are very different from the wetland indicator species that show up on eco-survey reports. They can help devise a planting plan that can be implemented inexpensively and quickly to stabilize the soil and allow the contract to be closed out within a reasonable amount of time.

Landscape architects can provide common sense with a conscience for the team. While a horticulturalist might understand the plant profile of a wetland plant, the landscape architect can foresee the ultimate height of proposed trees and predict how unmaintained natural succession might compromise the safety clear zone or a utility easement. Most eco-restoration team members, typically, are not familiar with unique plant species characteristics and would happily use Red Maples and Dogwoods on every plan drawing. Those trees are familiar, but might be poor choices for the specific site situation.

An environmental task order for road-building impacts to streams needs to include a provision for designing vegetative plans for disturbed stream buffers, with the responsibility clearly designated. The design work might fall to a civil engineering firm that is designing the road infrastructure, without any experience in planting restoration work. A multidisciplinary road project alliance created for bidding on a road project must hire a specialist for the vegetative planting plan. They might assume the consulting environmental technical experts are capable of plan design, only to find out, post-bid, the ecologists only do detailed ecological survey work and don’t have a designer on staff. If the scope of services includes vegetative plan design responsibility up front, then bids for environmental services and roadside design will include the extra cost. If the responsibility isn’t spelled out in writing up front in the task order, your project might be scrambling for guidance and mitigation designers after the initial surveys indicate a need for mitigation.

New contours on disturbed sites, especially roadside widening projects, are often too steep to establish stability with plant material alone. Many engineers are unaware that establishment of plant material is difficult on 2:1 slopes, and that steep slopes are in conflict with vegetative methods of restoration. They have seen roadsides stabilized with tenacious Lespedeza or Weeping Love Grass and assume any plant will do just as well on a steep slope. Regulatory agencies prefer simple, old-fashioned, native vegetation planting. Landscape architects can educate the team on optimal slope soil angles where roots can grow and seeds will germinate.

stream scour, stream buffer scour, failed stream bank

Stream buffer sites disturbed by construction can be complex or even dangerous. The volume and velocity of water flow can scour an entire bank in a single storm event and cause sediment to overflow strong silt fence barriers. Civil engineers play an important role in adapting the stream morphology of complicated water systems dislocated by extensive construction grading. The hydrology must be made right before restoration planting can begin. The civil engineer’s strong focus on grading efficiency and immediate costs can sometimes blind them to the need for gentle bank slopes when replanting the buffers. Working with a landscape architect, they can utilize a more complete design approach, and grading that welcomes plant establishment.

In some ways, using vegetation to stabilize a stream buffer competes with erosion control industry structural products. Mitigation plant material is cheap. Vendors make more money if their manufactured goods are incorporated into the plan as a BMP. Also, lots of blankets and logs and rip rap on the site might appear to field inspection engineers to be accomplishing more than trifling groups of small seedlings and scattered wheat straw mulch. Landscape architects can communicate the benefits and cost savings of simple grading fixes and going green with actual, living plant material.

Landscape architects can read and analyze stormwater conveyances and stream morphology, going beyond calculations to evaluate the proposed sinuosity of a new stream channel and how well it naturally suits the local surroundings. They can help soften the sharp corners of stream channels crafted by an engineer’s geometric formulas and design a plan to protect an existing, bank-stabilizing tree. While clear-cutting may seem like the easiest choice, a landscape architect can point out a solution that is even better, saving time and money for the project.

A valuable contribution a landscape architect can bring to the team is their ability to communicate with two-dimensional graphics in a manner that has visual clarity for a landscape subcontractor. Wetland scientists use complicated charts and graphs and map data. Engineers use incremental road alignment profiles that impart limited information about the unique landscape features of the site. It is rare for color renderings to be used for roadside stream relocation proposals, so the vegetative mitigation planting plans must be able to indicate boundaries for seed mixes, new and proposed contours, protection for existing trees, and locations of new seedlings in plain and simple black-and-white representations, without distracting and superfluous lines and patterns. Landscape architects can create drawings that help vegetative restoration plans read clearly to bidding contractors, rather than hiding the proposal under multi-layers of reference files within the road mainline section of the plan sheet set.

stream restoration, mitigation planting, vexar tubes

Maintenance is seldom discussed during the restoration planning process, but it should be. Everyone agrees good maintenance is important, but the only way to ensure quality maintenance is to include performance-based details in the contract specifications. It would be great to hold the contractor to a decade or more of care for a newly-planted site, but budgets and scheduling realities won’t allow that luxury. For roadside projects, there are strong political and funding issues that force quick-and-expedient remedies, pushing through a streamlined close-out of the contract. A decade is too much to ask, but you can dictate a reasonable minimum plant establishment time. It takes at least a couple of growing seasons for bare root seedlings to connect with the soil and start actively taking up nutrients and water. A newly-installed multitrophic landscape needs time to build resistance to weather extremes and develop the strength for self-sustaining growth. A written maintenance mandate with strong consequences for loss of plant material is essential. Landscape architects can create the specifications to monitor and enforce conditions for viable plant material with establishment time periods, inspections, and replanting requirements.

Competition for the restoration project market is keen. History has shown that limiting participation to single specialties and inexperienced optimists will not work, but there will always be firms that try to do just that. Don’t expect a multidisciplinary team to automatically appoint a landscape architect firm as part of their eco-restoration team. You will need to prove your worth.

For roadside projects, start, if possible, by becoming prequalified for multiple classifications on the state department of transportation lists. Ask to play a small part on a restoration project crew, and spend some time in the field with contractors to hear their perspective. Join a wetland scientist doing field work on an ecological survey report. Take courses and webinars conducted by seasoned professionals. Visit completed restoration projects. Market your experience on mitigation planting plans to firms that routinely do large road projects and let them know this essential service should be a part of many environmental task orders.

A landscape architect combines construction training and an understanding of plant material to provide value to restoration projects, but their most important contribution is the ability to combine creativity with a broad understanding of how all the pieces of environmental expertise puzzle can coalesce into strong drawings and effective specifications to communicate to contractors how to install and maintain restoration plantings that work.

You Can Read More About wetland stream restoration planting in the draft version 0.0 of the new Advanced Guide to Environmental Mitigation Planting eBook, based on years of experience working with the pros and providing guidance for the most efficient and cost-effective way to plant stream relocation, storm water retention, and wetland projects.

The Advanced Guide to Environmental Mitigation Planting



Success of Roadside Stream Restoration Projects