Field Design + Trail Alignment
Scope Tip
Clearly define what the field design deliverable will be—for example, a field-flagged alignment, GPS/GIS data, or both—and the expected level of accuracy and documentation. Also identify required control points and what may be determined or adjusted in the field.
Scope Item Definition
Identify and delineate the detailed trail alignment within the selected trail corridor through on-the-ground field design. Field trail design applies trail specifications, control points, site conditions, sustainability principles, and desired user experience to determine the specific location and characteristics of the trail, including trail centerline, turns, crossings, structures, and other trail features.
Field design may be completed before construction, incorporated into the construction contract, or shared between the designer and construction contractor.
When / Where It Applies
Field trail design translates the broader trail corridor and conceptual plan into a specific, ground-truthed trail alignment.
Field design may be completed as a separate planning/design phase before construction or as part of the construction contract. It may also be a collaborative effort, with the designer establishing key control points, features, or portions of the alignment and the construction contractor determining or refining the detailed alignment and trail flow between them.
The appropriate approach depends on project complexity, trail type, site conditions, land manager and permitting requirements, construction method, and the level of flexibility desired during construction.
Scope Considerations
Depending on the project, the scope should consider and clearly define:
Approved corridor, planning area, and required connections or control points within which the alignment will be developed.
Intended trail users, experiences, trail types, and applicable design criteria.
Required trail length, width, grades, cross-slope, turning characteristics, difficulty, accessibility, or other design parameters.
Required field investigation and level of on-the-ground design.
How terrain, soils, rock, drainage, vegetation, environmental resources, existing infrastructure, and other site conditions should inform the alignment.
Requirements for locating and incorporating control points, including opportunities, constraints, crossings, connections, and areas to avoid.
Whether structures, drainage features, specialty features, or other significant trail elements should be identified or preliminarily located during field design.
Required coordination with landowners, agencies, stakeholders, or other project partners.
Required review, refinement, or approval of the alignment.
How the final alignment will be documented, such as physical flagging or marking, GPS track, GIS data, electronically routed alignment, or a combination.
How the field design will be used for permitting, cost estimating, bidding, construction, or subsequent design development.
Owner-Provided Information
The owner should provide the following, if available and applicable:
Approved corridor plans, conceptual plans, feasibility studies, or other preceding planning and design work.
Available mapping, GIS data, surveys, aerial imagery, topographic data, or property information.
Known control points, connections, opportunities, constraints, or areas to avoid.
Information on existing trails, roads, facilities, infrastructure, utilities, access points, and land uses.
Known land ownership, easements, agreements, or jurisdictional boundaries.
Known environmental, cultural, regulatory, permitting, or resource constraints.
Applicable agency or land-manager standards, policies, trail specifications, or design criteria.
Previous stakeholder, agency, landowner, or public engagement and relevant findings.
Deliverables
Depending on the scope, deliverables may include:
Field-designed and marked trail alignment.
GPS/GIS data documenting the trail centerline and significant features.
Maps or spatial data identifying turns, crossings, structures, control points, and other significant features.
Field design notes or construction notes.
Identification of structures, crossings, or other features requiring additional technical design.
Documentation required for land manager review, permitting, or environmental review.
Documentation of required control points, fixed alignment segments, and areas where the construction contractor has flexibility to complete or refine field design.
Final or as-built alignment data reflecting significant changes made during construction, when required.
Pricing & Payment Considerations
The solicitation should clearly define the anticipated level of effort and pricing considerations, including:
Approximate trail mileage to be field designed.
Terrain, access, vegetation, and overall site complexity.
Trail specifications and complexity of the intended trail experience.
Anticipated structures, crossings, and other significant features.
Number of anticipated field days or site visits.
Required field marking, GPS/GIS data collection, mapping, and documentation.
Mobilization and travel requirements, including whether travel time and expenses should be included in the proposed price or reimbursed separately.
Meetings, field reviews, and coordination requirements.
Owner or land manager review and revision expectations.
Whether specialized technical or resource studies are included or provided separately.
When field design is included in construction, how field design effort and changes resulting from unforeseen site conditions will be incorporated into construction pricing.
Pricing may be structured by trail mile, lump sum, or time and materials with a not-to-exceed amount, depending on how clearly the trail mileage, site conditions, and required level of effort can be defined.
Common Scope & Contracting Issues
Not clearly defining whether field design will be completed before construction, by the construction contractor, or collaboratively.
Not clearly distinguishing between the broader trail corridor and the specific field-designed trail alignment.
Assuming that a conceptual trail plan or mapped corridor constitutes detailed field design.
In a collaborative approach, not identifying which control points, features, or portions of the alignment are fixed and where the contractor has design flexibility.
Providing a fixed alignment while also expecting the contractor to make field-based design decisions without defining the contractor’s authority to modify it.
Not providing sufficient flexibility to respond to surface or subsurface conditions discovered during construction.
Not clearly defining the contractor's field design authority, including applicable trail specifications, desired trail experience, performance requirements, and limits on field adjustments.
Not defining which field adjustments require owner, land manager, designer, or regulatory approval.
Not defining field-marking, GPS/GIS documentation, or final/as-built documentation requirements.
Not clearly identifying whether additional construction documentation, engineering, permitting, or technical design will be required before or during construction.