DEPARTMENT OF TRANSPORTATION SPECIAL PROVISION FOR COMPENSATORY WETLAND MITIGATION DESIGN, CONSTRUCTION AND MONITORING

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1 DEPARTMENT OF TRANSPORTATION SPECIAL PROVISION FOR COMPENSATORY WETLAND MITIGATION DESIGN, CONSTRUCTION AND MONITORING January 14, 2009June 16, 2009 I. GENERAL The following Requirements provide guidance in the design, construction, post-construction compliance monitoring, and remediation of compensatory wetland mitigation sites. The Design- Build Team shall be responsible for coordinating preliminary and final design review with the Virginia Department of Transportation (VDOT). Review shall also be coordinated with the Virginia Department of Environmental Quality (VDEQ) and the Army Corps of Engineers (Corps), collectively referred to hereinafter as the Agencies. The Design-Build Team shall deliver a functioning, successful site --- as defined by the goals, objectives and permit requirements --- that has been released from further monitoring by the Agencies. Project-specific requirements are presented below. II. REQUIREMENTS The goal of the is to design, build and maintain a functionally successful wetland complex that provides partial compensation for unavoidable impacts associated with ACOE permit number NAO and VDEQ permit number To meet this goal, objectives include: 1. Developing at the Malbone site at least acres of wetland restoration and creation and 4.74 acres of palustrine emergent wetland enhancement. 2. The final site design must include 7.9 acres 3.16 acres of palustrine emergent wetland (3.16 acres of creation/restoration and 4.74 acres of enhancement), 0.1 acres of scrubshrub wetland and acres of palustrine forested wetland. 3. No less than acres of this forested wetland should have a hydrologic regime consistent with a Cowardin classification of PFO1E and should be dominated by bald cypress (Taxodium distichum) and black gum (Nyssa sylvatica var. sylvatica). Additional forested hydrologic regimes are encouraged. 4. Key milestones in site design, construction and success monitoring will meet timelines imposed by the Agencies. A. DESIGN At a minimum, the Design-Build Team shall produce one interim design and a final design, including the mitigation narrative, for review and acceptance by VDOT and the Agencies. The content of the mitigation narrative is specified by the permits referenced above and shall include, at a minimum, the approach to each element of design, construction, compliance monitoring, and remediation to meet the Project goals and objectives. The final design shall indicate the means by which the Design-Build Team will achieve the areal coverage of community types required under the Contract, taking into consideration existing site conditions. The Design-Build Team shall develop and employ an adaptive management plan which identifies potential challenges (e.g., flooding, drought, invasive species) that pose a risk to project success and include a discussion of how the final design, as well as the construction, monitoring and maintenance practices, accommodates these challenges. The Design-Build Team s adaptive management plan shall also address potential remedial measures in the event mitigation does not meet performance standards in a timely manner. This should be submitted with the mitigation narrative. Special Provision For Page 1 of 6

2 B. CONSTRUCTION 1. EARTHWORK Site conditions may include a high water table at or near the ground surface in some areas that may be intercepted during construction. Earthwork may encounter running sands. Construction practices shall include measures to avoid or remediate undesired effects associated with these conditions (e.g., rutting or inability to maintain desired grades) to the maximum extent practicable. 2. GRADING TOLERANCES Site construction and the As-Built Survey shall demonstrate the following design tolerances: a. Final grade within the site shall be within 0.2 foot vertically and 0.5 feet horizontally of the design elevations. b. Structure elevations shall be within 0.1 foot vertically and 0.2 feet horizontally of the design elevation and position. Any modifications to site design during construction shall be documented as required by permit and in the QA/QC Management Plan for this Project. 3. COMPACTION The Design-Build Team shall address in the design and mitigation narrative how compaction will be avoided or remediated during site construction. In the event that compaction of the subgrade is required as a design component to achieve desired site hydrology, the Design- Build Team shall describe in the design and mitigation narrative to what density compaction is required for that feature and how compaction within the planting medium will be avoided or remediated prior to planting the site. 4. VEGETATION ESTABLISHMENT AND MANAGEMENT The Design-Build Team shall address how the site will be prepared for seeding and planting. The Design-Build Team s site preparation shall minimally address soil and seedbed preparation and a schedule of site preparation activities. a. Soil stabilization shall be applied within 7 days after attaining the appropriate grading increment for that stage of the construction operations, or upon suspension of grading operations for an anticipated duration of greater than 15 days, or upon completion of grading operations for a specific area. b. The As-Built Survey must be submitted and accepted by the Agencies prior to planting. The As-Built Survey may be completed and submitted in phases to expedite review and insure that sites are stabilized and planted in a timely manner. c. Planting of woody vegetation shall not occur until after hydrologic monitoring has been conducted for the time specified in the permits referenced above and the Agencies have reviewed and approved the Project for planting, unless authorization to do otherwise is expressly authorized by the Agencies in writing. d. Planting materials shall conform to the requirements of Section (i) of the Road and Bridge Specifications with the following amendments: 1) Nursery grown plants shall have fully developed rooting and branching systems. Plants shall conform to the American Association of Nurserymen (AAN) standards for bare root, peat pot, and containerized stock (ANSI Z ). Special Provision For Page 2 of 6

3 2) Plants shall be obtained from approved sources within hardiness zone 7 or 8. 3) Soil mixture used for backfilling planting pits shall be existing, in-place soil with fertilizer added in accordance with Sections 603 and 605 of the Road and Bridge Specifications unless otherwise shown on the final design plans. 4) No change in the quantity, size, kind, hardiness zone, or quality of plants from those specified will be permitted without the approval of the Corps and VDEQ. The suggested substitutions must be grown in a climate similar to the hardiness zone specified, must be native non-invasive species which have the same indicator status, must meet the required minimum number of species, and must conform to the requirements of the Contract. C. COMPENSATION SITE SURVEY REQUIREMENTS As-Built and annual monitoring survey requirements shall follow the Special Provisions for Compensation Site Survey Data Requirements. D. POST-CONSTRUCTION COMPLIANCE MONITORING AND REMEDIATION 1. Monitoring parameters, frequencies and sampling densities are dictated by ACOE Permit Number NAO and VDEQ Permit Number The final monitoring plan based upon these permits and the final design shall be included in the Mitigation Narrative required in Section II. A, above. 2. Annual monitoring reports shall be prepared using the current VDOT Mitigation Monitoring Report Template, included in the RFP Information Package, and submitted to the Agencies and VDOT for review and acceptance. 3. Annual mitigation monitoring reports shall be submitted, in pdf format and hard copy, to the Agencies and the VDOT Authorized Representative. In addition, for VDOT s use only, all digital data shall be submitted in a zipped format preserving file folder structure specified in the File Naming and Structure Protocol, included in the RFP Information Package, and shall include: a. All raw data; b. All tables, figures and CADD drawings in one of the following acceptable digital formats (Excel, Word, Microstation, ArcGIS, tiff, or jpg file formats); and c. All site photographs. E. QUALITY ASSURANCE/QUALITY CONTROL QA/QC for design, construction and monitoring shall be the responsibility of the Design-Build Team and shall include, at a minimum, the Witness and Hold Points: QA/QC requirements for Clearing and Grubbing, Pre-cast Structures, Erosion and Siltation Control, Topsoil and Seeding, and Planting shall be in accordance with design plans and Tables and Table as found in VDOT s Minimum Requirements for Quality Assurance & Quality Control on Design Build & Public-Private Transportation Act Projects, August Additional QA/QC Requirements are presented in Table 2 of this Special Provision. Minimum requirements for inspection, sampling, and testing for this contract are contained in Table 3 of this Special Provision. The tasks included in Table 1 shall be incorporated into the Project Schedule as project milestones. Special Provision For Page 3 of 6

4 Table 1: Witness and Hold Points Tasks/Materials Witness Point Hold Point Preliminary Design Final Design and Mitigation Narrative Clearing and Grubbing Erosion and Siltation Control Water Control Structures and Berms Topsoil and Seeding Final Grade As-Built Survey Post-Construction Hydrologic Monitoring Planting Risk Monitoring Annual Monitoring Remediation Final Site Release Special Provision For Page 4 of 6

5 Table 2: QA/QC REQUIREMENTS FOR WETLAND DESIGN-BUILD Material Type Spec. Section Contractor s QC Survey Design plans and Spec. Provision for Compensatory Mitigation Site Survey Data Requirements Contractor s QA Frequency VDOT s IA Frequency VDOT s IV Frequency Conduct routine inspections of grades during construction and prepare Final Grade As-Built Survey Monitoring Conduct Post-Construction Hydrologic Monitoring prior to planting Permit Requirements, Design plan notes and special conditions Permit Requirements, for agency acceptance prior to planting Daily Per requirements specified in agency permits Upon completion of each phase or planned community type Per requirements specified in agency permits Site inspection upon completion of each phase or planned community type Annual, visual inspection during the growing season Review Final As- Built Survey upon completion and Agency approvals Receipt of report upon satisfaction of hydrologic criterion Conduct regular site reviews to document identified/potential risks to site success during the Establishment Period Annual Monitoring to document site success Permit requirements Monthly Quarterly Quarterly Annual Review documentation and at the end of the establishment period Per requirements specified in agency permits Annual monitoring report submittal Annual, visual inspection to assess site performance Receipt of final report and electronic deliverables on established schedule. Remediation As Required by the Corps and VDEQ Review documentation and agency approvals of remediation plans. Special Provision For Page 5 of 6

6 Table 3: DESIGN-BUILDER REQUIREMENTS FOR INSPECTION, SAMPLING, TESTING OF DEFINABLE FEATURES FOR WETLAND DESIGN-BUILD WORK Item of Work Preparatory Inspection Intermediate Inspections Minimum Frequency of Completion Inspection Intermediate Inspections Final Grade As- Built Survey Once during each phase Review QA/QC requirements, items of work and the required frequency of IA and IV Inspections, design specifications and reporting requirements for the As-Built Survey prior to beginning grading to achieve final grade. Design-Build QA Manager to submit documents to VDOT and agencies (hold point) upon completion. Inspection of grading operations upon completion of each phase or planned community type. Phased completions must be submitted for review and acceptance of the Army Corps of Engineers and VA Dept. of Environmental Quality Final grade As-Built Survey must be reviewed and accepted by the Army Corps of Engineers and the VA Dept. of Environmental Quality. Confirm acceptance by both agencies and report discrepancies to the QAM for resolution, if necessary. Post- Construction Hydrologic Monitoring Review QA/QC requirements, items of work and the required frequency of IA and IV Inspections, design specifications, permits and reporting requirements prior to initiating post-construction hydrologic monitoring At least weekly, for 10 weeks during the growing season, or until the wetland hydrology success criterion is met. Post-Construction Hydrologic monitoring data must be reviewed and accepted by the Army Corp of Engineers and the VA Dept. of Environmental Quality. Confirm acceptance by both agencies. Design-Build QA Manager to submit results to VDOT and agencies (hold point) upon completion. Annual Monitoring Review QA/QC requirements, items of work and the required frequency of IA and IV Inspections, design specifications, permits and reporting requirements prior to initiating post-construction monitoring Submit annual monitoring report to VDOT, DEQ and ACOE and electronic deliverables to VDOT. Confirm receipt and acceptance of annual monitoring results. Deficiencies requiring remediation must be addressed to the satisfaction of both DEQ and the ACOE. Special Provision For Page 6 of 6