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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 improved by experiencing both. Knowledgeable mitigation experts learn from the in-the-field challenges of vegetative restoration. There are many different factors that contribute to a stable, dynamic equilibrium for stream channel sediment. Well-established native vegetation on the stream buffers is an essential part of that stability. A landscape architect can help design and coordinate a good native vegetation plan, boosting the chances for success in permanent stream stabilization.

Eco-restoration teams for projects large and small benefit from a landscape architect’s perspective and participation. The professions that provide bioengineering expertise have become highly specialized, but they still need to incorporate good horticulture, landscape design, engineering, and landscape maintenance knowledge into a workable, sustainable landscape restoration plan. They need an experienced vegetative mitigation landscape designer on board. Teams 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. Landscape architects have the big-picture perspective.

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. 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. 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 similar native plant 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 can create to-scale drawings to communicate the installation process to the contractor. They can predict how unmaintained natural succession might compromise the safety clear zone or a utility easement. They can articulate a proposal to a reviewing agency which pulls together the budget, the plans, the specifications, and adherence to environmentally sound principals. If you are new to restoration planting work, it pays to consult with seasoned professionals and get advice, reviews, and comments from them during the planning and design-drawing phases of the project. It pays to consult with a landscape architect motivated to heal the disturbed stream site in the most practical, efficient manner.

Environmental task orders for road-building impacts to streams need to include a provision for designing vegetative plans for disturbed stream buffers, with the responsibility clearly designated. The design work often falls to a civil engineering firm that is designing the road infrastructure, without any experience in planting restoration work. 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. A good multidisciplinary road project alliance, created for bidding on a road project which will impact streams, should hire a specialist for vegetative planting plans. The agency contract scope of services should be written to include such a specialist. If the scope of services includes vegetative plan design responsibility up front, then bidders for environmental services and roadside design will include the extra cost in their bids. If the responsibility isn’t spelled out in writing 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. A landscape architect is able to advise engineers on how to shape the grading plan to support healthy plant life.

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 design grading plans that welcome 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. Lots of blankets and logs and rip rap on the site might appear to construction field inspection engineers to be accomplishing something substantial. A trifling group of small seedlings and scattered wheat straw mulch lacks the visual strength of structural erosion control products, but vegetative methods of controlling erosion, when done well, can be more effective. Going green with actual, living plant material is preferred for cost reasons as well as for its effectiveness. Landscape architects can communicate the benefits and cost savings of simple grading fixes to facilitate vegetative fixes.

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 tweak a stormwater plan to protect existing, bank-stabilizing trees and vegetation. While clear-cutting may seem like the easiest choice, and is the default method for road construction, a landscape architect can point out a solution that is even better, avoiding expensive grading and 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, graphs, and map data. Engineers use incremental road alignment profiles that impart limited information about the unique landscape features of the site. 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 file clutter 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 a landscape architect can draft landscape installation contracts that include a reasonable minimum plant establishment time and a maintenance plan. 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-specialty practitioners and inexperienced optimists will not work well. There will always be bidding teams that try to do just that. A landscape architect must prove their worth as part of an eco-restoration team, and experience is the only way to do that.  If you are a landscape architect, push to be made part of a multidisciplinary, restoration team to gain proficiency. Seek mentors to guide you through your first projects. Become prequalified for multiple classifications on the state department of transportation lists to make your firm available for teaming agreements. 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 their ability to combine creativity with a broad understanding of how all the pieces of environmental expertise puzzle fit. A landscape architect’s skills can coalesce into strong vegetative mitigation drawings and effective specifications to communicate to contractors how to install and maintain restoration plantings that succeed.

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