WETLANDS, PERMITS, AND CONSTRUCTION INSPECTION Project Inspectors Conference Wilsonville, Oregon Presentation by: Oregon Department of Transportation Environmental

WETLANDS, PERMITS, AND CONSTRUCTION

INSPECTION

Project Inspectors ConferenceWilsonville, Oregon

Presentation by:Oregon Department of Transportation

Environmental ServicesFebruary 2000

What is a wetland?

Water resource that has three characteristics:

• Wetland hydrology - Water that is present in depths less than 6 ft., or soils are saturated, for 10 days or more during the growing season for the prevalent vegetation;

• Hydric soils - Soils with physical and chemical characteristics that are associated with lack of oxygen in the soil;

• Hydrophytic vegetation - Vegetation uniquely suited for growing in water or saturated soil conditions.

Water/Wetland Protection Regulations in OregonFEDERAL STATE OF OREGON

Clean Water Act Fill and Removal Law

Regulatory authority through the Regulatory authority through Environmental Protection Agency the Division of State Lands

Implementation Implementation

Army Corps of Engineers Division of State Lands

Section 404 Permit Fill and Removal Permit

What does this mean for highway projects?

The potential affects of transportation projects on protected water resources must be identified and considered in developing new projects, or in maintaining existing transportation facilities.

If protected water resources are identified as being potentially affected by a transportation project, then regulations must be followed and federal and state permits obtained.

“Water Resource” Permits and Their Requirements:

Section 404 Permit DSL Permit

Both permits require that wetland resources:

First: Must be avoided if at all possible;

Second: Unavoidable impacts must be minimized;

Third: Impacted wetland values must be replaced, usually through mitigation

Permit Requirements

Avoidance and Minimization:

– Alignment modification/adjustment– Use of bridges, retaining walls, steepened

slopes for project

– Limits of construction/fenced project wetland areas

Permit Requirements

Replacement of lost or affected wetland values by:

– Restoration of pre-existing wetlands– Construction of new wetlands– Enhancement of existing wetlands

The success of the mitigation effort is evaluated through a five-year post-construction period.

Wetland Mitigation

Project Design Phase:

1. Review mitigation possibilities

2. Determine appropriate

mitigation approach

If construction is the appropriate approach to replace lost values, then

a mitigation site must be selected

Wetland Mitigation Site Selection

Mitigation site selection is based on:

– Size/acreage requirements of mitigation– Access to appropriate hydrology– Type of wetlands needed to replace lost

values/functions– Availability of the site

Wetland Mitigation Site Design

Mitigation site design is based on:

• Hydrology, hydrology, hydrology! • The type of wetlands/values being replaced;

• The minimum area requirements to achieve replacement of lost or impacted values.

Most Fundamental Wetland Mitigation Design Concept

• Hydrology is the most critical element for restoration or creation of mitigation wetlands

• If appropriate wetland hydrology is established, wetland plant communities and hydric soils will develop

Hydrology

Wetland hydrology is obtained by:• Diverting/retaining water from a stream,

creek, ditch, existing wetland• Excavating to ground water level• Breaching dikes/levees or other water

control structures to restore water to a de-watered area

• Removing or modifying functioning drainage structures

Wetland Construction

Wetland Mitigation ConstructionThe wetland mitigation construction sequence:

1 - Site Preparation (Clearing and Grubbing)2 - Excavation/Embankment (Grading)3 - Planting4 - Establishment Period Monitoring

Grading the mitigation site early in the project may allow one season of hydrology monitoring and correction if needed

Mitigation Construction

Site Preparation/Clearing and Grubbing

• Wetland soil salvage areas • Plant salvage areas• Special treatments for clearing/grubbing

of mitigation site– Vegetation removal or soil sterilization

• Burning• Spray with herbicides• Stripping and export of topsoil


Mitigation Site

How will wetland hydrology be achieved?

Stream diversions, expansion of existing wetlands, detention of overland flow, excavation to ground water, dike removal, removal of surface and subsurface drainage systems

This is the most important component of successful mitigation site construction


Excavation and Embankment Select Topsoil• Salvaged wetland topsoils

– Storage and treatment - generally stockpiled on-site in linear piles no deeper than 4 ft.

– Piles need to be watered regularly if stockpiled during summer

• Strip topsoil from mitigation site– Discard the top 15 cm (6”) of topsoil


Excavation and Embankment • Soil Stripping (cont.)

• This helps remove undesirable vegetation from the mitigation site and keep weedy vegetation from immediately becoming re-established on the site

• Stockpile the remaining topsoil• Plants that will eventually be planted on the site will

need the nutrients and texture of top soil to grow • If the top soil is stockpiled for longer than 2 months,

may need erosion control, some other protection from weed infestation


Excavation and Embankment

Rough Grading:

• How much overburden is to be removed?

• Will there be backfill? How thick?• Water control structures - finish

elevation achieved• Slope gradient - gradual• Seasonal wetlands, permanent or semi-

permanent open water



Finish Grading:

• Top soil: Top soils are needed for planting if more than 18” is excavated from the mitigation site surface. The finish elevation should be achieved after the top soils have been backfilled.

• Surface roughness: Surface irregularities provide more wetland diversity.



Finish Grading (continued):

• Soil compaction: Before planting, the surface of the mitigation site needs to be scarified to loosen the surface.

Grading/excavation is generally how wetland hydrology is developed on the wetland mitigation site. This is the most critical element for the success of the wetland mitigation effort!


Site Protection

Sites are frequently graded several months before planting.

• Weed control: Bare soil sites can become infested with weedy species - weed control/sterilization of the site prior to planting needs to be considered.

• Erosion control: Stabilization of bare soil - is it needed?


PlantingPlant materials• Native plants almost exclusively

– What forms/sizes are spec’d? Generally, smaller has better survival rate

– Sources are variable - check with wetland specialist if unsure of appropriate sources

– Condition of plants - sometimes poor quality plants


Planting (continued):Plant materials

– Condition of Plants - Plants sometimes overgrown in pots, unrooted shrub cuttings, cuttings too small


PlantingPlant Materials• Seed:

– Always native seed– Quantities - difficult to get– Does the seed need to be hand-collected?

If so, need:• Timing- Can the seed be collected in time for

planting window?• Seed certification - or the seed must be

furnished in time to be tested!


PlantingInstallation:

Planting window– Soil amendments - frequently no fertilizers

backfill planting holes with native soil– Appropriate installation technique

• Watch for cutting installation - poked into the ground isn’t it!

– Mulch - to or not


PlantingInstallation:Seeding

– Seeding window– What type of seeding method?– Mulch and tackifier– Adequate coverage


Planting

Establishment and Maintenance– Establishment period - one year or longer?– Watering - Needed - especially for summer– Weeding - Need a reasonably weed-free

site - minimum of no noxious weeds– Vegetative success standards - what is

acceptable % of cover or survival?

CONSTRUCTION ISSUESWetland Mitigation SitesAn appropriate site is the best guarantee for a

successful mitigation effort.

Site selection concerns:

– The presence of appropriate hydrology for a proposed mitigation site may be difficult to determine without extensive, time-consuming and expensive study.

– Political considerations may dictate or affect mitigation site choices.

– Project development timeframe may limit site information gathering.

CONSTRUCTION ISSUES

How the transportation contracting process affects the outcome of wetland mitigation:

• Highway plans and specifications are best for

highway construction, not natural resource work or mitigation

• Highway contracting process favors highway construction, not natural resource work

• Subcontractors who do mitigation for primes are seldom specialists in mitigation work

CONSTRUCTION ISSUES

Continued . . .

• Different elements of mitigation are frequently constructed by different subcontractors (specifically, grading and planting)

• Timing and staging of mitigation construction cannot be controlled

• Mitigation sub-contractors are reluctant to do all the establishment period maintenance requirements

CONSTRUCTION ISSUES

Other Issues Affecting Mitigation Outcome: Wetland construction/creation is a new scientific

field. The information needed to support applied wetland science is not always available.

Native plants and seeds are a relatively new horticultural demand. There is little scientific study to document best horticultural practices.

There are few experienced wetland construction contractors.

CONSTRUCTION INSPECTION

Critical Elements for a Successful Wetland Mitigation Project

– Pre-bid review of plans and specs to determine if they are clear and can be implemented and are legally defensible.



– Pre-construction field review of the wetland/natural resource component.

Include the wetland specialist, planting contractor, grading contractor and prime contractor, as well as sub-contractors to the planting contractor



Review special issues with the mitigation sub-contractor for early resolution

Seed collection, cutting collection, native plants, special treatment of the site



– Call the wetland specialist for clarification if questions arise during construction.

ODOT Wetland Specialist should review rough grading, finish grading, planting and seeding completion

FUTURE CONSIDERATIONS

Possible proposals to address some of the issues that affect outcome:

1) Develop better, tighter construction specifications, especially for plants and seeding.

2) Develop some expertise in horticultural aspects of plant inspection.

3) Separate contracts for wetland mitigation and other natural resource work.


Additional steps that can be taken to:

1)Help the project inspectors with their day-to-day inspection of mitigation projects; and

2)Ensure the construction of a successful mitigation site.

CONSTRUCTIONPermit Requirements

Section 404 (federal) and Removal/Fill (state) Permit Requirements and Conditions:

1) 404 and DSL permits on site at all times;2) Protect wetlands adjacent to the project;3) Protect off-project wetlands by appropriate and legal disposal of excess material;4) Construct mitigation sites; and5) Monitor after construction and correct failed or marginal mitigation efforts.

Permit Requirements

Protect Wetlands Adjacent to the Project

Implemented by:

• “Limits of Construction”, or• Designated “No Work Areas”, or• Fenced areas.

Review staging areas to make sure they are not in wetlands. If in doubt, call a wetland specialist to check.

Permit Requirements

Protect Off-Project Wetlands

• Dispose of excess in approved, non-wetland sites

• Get any questionable proposed disposal sites cleared, if necessary, by a wetland specialist.

The permit holder, not the contractor, is liable for any fill violations.

Permit Requirements

Construct Wetland Mitigation

• Lost or affected wetland values must be replaced through:– Restoring lost or drained wetlands;– Constructing new wetlands– Enhancing existing wetlands

The permit will include the specific amount of mitigation that will be done as part of the project

Permit Requirements

Monitor After Construction

• Wetland mitigation sites begin to be monitored for permit purposes after plant installation

• Sites will be monitored for five years• Failure to meet any mitigation requirements

requires correction - and five more years of monitoring

Review of Plans and Specifications for Wetland Work

Roadway Plans• Areas of wetlands noted on plans• “No Work Areas” designated –

fenced or otherwise protected• “Limits of Construction” designated • Areas of “selected topsoil”

(salvaged wetland soils) designated on the plans


Wetland Mitigation Site Grading PlansElevations and excavation areas

– Final grade elevations clear– Original ground elevations clear– Final grade elevations clear or water control

structures related to wetland site Cross-Sections

– Sub-excavate and backfill– Depth of excavation– Depth of backfill


Wetland Mitigation Site Grading Plans - ContinuedDetails for Control Structure/Dikes, etc.

– Finished elevations are clear


Wetland Mitigation SitePlanting PlansPlanting Plan

– Types of planting areas are noted on plans– Seeding areas noted– Approximate area sizes noted

Plant List– Plant list matches plans– Seed lists match seeding area names


Planting Plans - ContinuedPlanting Details

– Drawings to clarify cutting/stake planting– Drawings to clarify other plant materials


Specifications/Special Provisions to Review

Section 00320 - Clearing and Grubbing

Section 1010 – Topsoil

Section 1031 – Wetland Seeding

Section 1040 – Planting

Documents

WETLANDS, PERMITS, AND CONSTRUCTION INSPECTION Project Inspectors Conference Wilsonville, Oregon Presentation by: Oregon Department of Transportation Environmental