This presentation will discuss how NAACC scoring methodology is being incorporated in project objectives and being adapted to produce forecasted post construction scores.
NAACC – North Atlantic Aquatic Connectivity Collaborative has a well-established framework for scoring impairments to aquatic organism passage (AOP). Certified users input field data into the online database in order to receive the final score.
New York State Department of Transportation (NYSDOT) has > 9200 large culverts (5-20’) on state roads. In addition to regularly scheduled culvert projects, NYSDOT is currently pursuing a separate Large Culvert Program focusing on >350 structures across upstate NY that were identified based on existing structural impairments. Based on the type of structural impairment, these culverts were preliminarily identified for rehabilitation (including linings) or replacement with another culvert or a bridge.
Improvement to AOP is included as an objective for this program. Design consultants are on board and additional data gathering, surveying and preliminary engineering is occurring for this program. Design consultants’ scope of work includes adhering to state and USACE permit conditions related to culverts. In addition, as part of preliminary design and the process of confirming scope of the work Design Consultants are to:
Identify NAACC score to evaluate AOP at each crossing. Consultants will be completing AOP assessments in the field using NAACC methodology and recording location information in a standalone document calculating the weighted score of the NAACC.
Review the weighted score and consider which features of the culvert related to the identified impairments (i.e. strongly influenced by the outlet drop to stream as being <1’ or by having a constriction of bankfull width)
Document within design approval documents what the forecast score would be post construction and whether it would meet the objectives to improve AOP:
For rehabilitations including linings: identify how any impairments regarding constriction or invert change are being offset by in-culvert or in-stream mitigation and what the resulting score of the proposed design would be.
For replacements: discuss any remaining potential impairments (i.e. if culvert slope may continue to not match adjacent slopes)
Questions surrounding preliminary design with weighted scoring calculations are anticipated since this product interface is challenging.
It is anticipated that in some cases decisionmakers may change originally identified scope of a rehab or lining to a replacement. It is more likely that the resiliency calculations for future flood risk will have more of an influence on this decision than the AOP itself. Increasing sizes for modeled future flood risk is anticipated to result in the sympathetic improvement to AOP.
NAACC scores will ideally be field checked after construction however, this has not yet been included in the environmental commitments for this program.