Implementation and Effectiveness Monitoring of Hydraulic Projects: Year-Five Progress Report

Purpose

WDFW is monitoring its hydraulic project approval (HPA) process to help ensure that hydraulic structures comply with current rules and that current rules effectively protect fish life. Monitoring provides feedback that should allow us to continually improve the HPA process. Because two parties are involved in hydraulic projects – WDFW (the permittor) and the permittee, the success of project implementation depends on the performance of both parties. Hence, we collect information that should allow us to improve the performance of both WDFW and the permittee.

This report covers: 1) implementation monitoring of culverts; 2) implementation monitoring of marine shoreline armoring; and 3) effectiveness monitoring of culverts.

Implementation Monitoring of Culverts

Successful implementation of an HPA permit for a culvert occurs when: 1) the issued permit or project plans include specifications for the five critical structural dimensions – culvert width, length, culvert slope, minimum countersink at the outlet, and maximum countersink at the inlet; 2) specifications conform to Hydraulic Code Rules¹ and/or follows WDFW’s design guidelines; and 3) the completed structure complies with its permit.

Overview

For 5 years from 2013 to 2017, we evaluated implementation of 263 new and replacement culverts in western Washington, an average of 53 culverts/year. The 263 culverts corresponded to 209 HPA permits because many permits covered two or more culverts. About half (49%) of the culverts were stream simulation design, 27% were no-slope design, and 21% were of unknown design.

Permit Compliance Rates for Culvert Structural Dimensions

We calculated compliance rates for each structural dimension. Compliance was best for culvert slope (82%) and worst for minimum countersink (40%). When we applied a compliance tolerance, slope had 93% compliance and minimum countersink had 60% compliance. We discuss the issue of compliance tolerances below. Compliance for culvert slope exhibited a statistically significant positive trend from 77% in 2013 to 87% in 2017

¹ In July 2015, WDFW instituted revised hydraulic code rules. Unless noted otherwise, references to the hydraulic code rules in this report refer to the rules in effect after July 2015.