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 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:
Field design responsibility: Define whether field design will be completed by the designer before construction, by the construction contractor, or collaboratively, and clearly establish each party’s responsibilities.
Field-designed alignment: Identify the specific trail alignment on the ground within the selected corridor.
Trail specifications: Apply established specifications and design criteria, including intended users, trail type, width, grade, difficulty, accessibility requirements, and desired trail experience.
Control points: Identify positive and negative control points that guide the alignment and distinguish required or fixed control points from areas where the detailed alignment may be adjusted.
Site conditions: Evaluate terrain, slope, soils, geology, hydrology, vegetation, natural and cultural resources, infrastructure, and other site-specific conditions that influence the alignment.
Trail features and structures: Identify the location and general configuration of turns, drainage features, water crossings, structures, and other significant trail features.
Field marking: Define how the alignment and significant features will be marked in the field and the required durability of that marking.
GPS / spatial documentation: Define requirements for documenting the alignment and significant features through GPS, GIS, or other spatial data.
Design flexibility: When field design is completed or refined during construction, define which elements are fixed and where the contractor has discretion to adjust alignment, trail flow, features, or structures in response to conditions encountered in the field, including subsurface conditions such as rock, groundwater or seeps, soils, and roots.
Review and approval: Define which field design decisions or changes may be made by the contractor and which require owner, land manager, designer, or regulatory approval.
Permitting and compliance: Identify any field design requirements or limitations established through environmental review, permitting, resource protection, or other approvals.
Construction documentation: Define whether the field-designed alignment will provide sufficient direction for construction or whether additional plans, specifications, engineering, construction notes, or other documentation are required.
Owner-Provided Information
The owner should provide the following, if available and applicable:
Selected or approved trail corridor and corridor mapping.
Conceptual trail plan and previous planning or design information.
Project goals, intended users, and desired trail experience.
Trail specifications and design criteria.
Applicable land and resource management requirements.
GIS/spatial data, mapping, and property or management boundaries.
Known positive and negative control points.
Natural and cultural resource information, avoidance areas, and other known site constraints.
Applicable permitting, environmental review, and approval requirements.
Required field-marking and GPS/GIS standards.
Known construction methods, equipment limitations, or implementation considerations that should inform design.
Defined roles and decision-making authority for the designer, construction contractor, owner, and land manager when field design responsibilities are shared.
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.
Giving the contractor design discretion without clearly defining trail specifications, desired user experience, performance requirements, or limits of that discretion.
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.