HomeMy WebLinkAboutPublic Works stormwater commentsOlympic Discovery Trail – Anderson Lake Connection Stormwater Review Page 1 of 2
Jefferson County
Department of Public Works
623 Sheridan St.
Port Townsend, WA 98368
(360) 385-9160
Monte Reinders, P.E.,
Public Works Director/County Engineer
Date: 1/26/2024
To: Planner, DCD
From: John Fleming PE, JCPW
Project: Olympic Discovery Trail- Anderson Lake Connection Shared-Use Path Project
(ZONS2023-00013, JCPW Project # 18019893, Road #850200)
Subject: Development Review, Stormwater Management
APPLICATION REVIEW
A. Stormwater Management
Unified Development Code Requirement(s):
The Jefferson County Unified Development Code, Sections 18.30.060, Grading and excavation standards and
18.30.070, Stormwater Management Standards both set standards for erosion and sedimentation control and
stormwater management. The code adopts the requirements set forth by the most current version of the Washington
State Department of Ecology, Stormwater Management Manual for Western Washington (SWMMWW). The most
current version is the 2019 SWMMWW.
JCPW Findings:
Jefferson County Department of Community Development has requested that the Department of Public Works
review a Stormwater Site Plan for temporary and permanent stormwater management prepared by Otak, Inc. for
project proponent Jefferson County Department of Public Works. The proposed project area is 22.7 acres. The
proposed development consists of a 3.2 mile long shared-use path of 8’ to 10’ wide paved surface, and 2’ to 4’
gravel shoulder, re-construction of driveway entrances, and surfacing of an equestrian trail. The project documents
consist of plans (Otak, 69 pages, 10-2023, Nico Vanderhorst PE), report with calculations (Otak, 206 pages, 1-24-
2024, David Ojala PE), and a geotechnical report by Aspect Consulting (73 pages, 12-21-2023, Erik Andersen PE).
The proposed trail consists of two areas: 1) adjacent to South Discovery Road, Four Corners Road (paved County
roads), and through Jefferson Transit property (parallel to Four Corners Road), and 2) adjacent to a utility corridor
gravel service road, then around the edge of a commercial forest. The trail proposes 243,590 square feet of new
impervious surface area, and 17,130 square feet of replaced impervious surface area. This proposal is subject to
Minimum Requirements (MR) #1 thru #9 of the 2019 SWMMWW. The Plan proposes to implement Best
Management Practice (BMP) T5.13 Post Construction Soil Quality and Depth for disturbed areas, BMP T7.20
Infiltration Trenches and BMP T7.30 Bioretention Trenches adjacent to the County roads, BMP T5.30 Full
Dispersion for the remainder of the trail.
Olympic Discovery Trail – Anderson Lake Connection Stormwater Review Page 2 of 2
JCPW Recommendations:
1. The proponent shall install the stormwater management facilities and implement the Best Management
Practices (BMP’s) per the Stormwater Site Plan, prepared by Otak, Inc. (10-2023, Nico Vanderhorst PE, 1-
24-2024, David Ojala PE)
2. Sites with greater than 1 acre of disturbance trigger the requirement to have a developer provided Certified
Erosion and Sediment Control Lead (CESCL) inspector and site log book, as per Element #12 Manage the
Project, of Minimum Requirement #2 Construction Stormwater Pollution Prevention. The CESCL
inspector must be identified by the time of start of construction, and must be present on-site or on call at all
times.
3. The proponent shall apply for an NPDES Construction Stormwater General Permit (CSWGP) administered by
WA State Department of Ecology.
4. Prior to commencing land disturbing activity, the proponent shall notify Jefferson County Public Works
(JCPW) and arrange a Preconstruction Meeting.
5. Before any construction begins on-site, erosion control facilities shall first be installed.
6. In accordance with the Jefferson County Unified Development Code, Section 18.30.080 (1) (f): Clearing,
grading, and construction of roads, bridges, utilities, and stormwater management facilities shall be
inspected by JCPW. In order to enable the department to conduct inspections in a timely manner, the
applicant shall notify the department in a timely manner regarding the project construction schedule.
Typical Inspections:
• Installation of temporary erosion and sediment control measures
• Clearing (and Grading) and road subgrade preparation;
• Placing roadway gravel base;
• Placing roadway crushed surfacing top course;
• Placing improved roadway surface (chip seal or asphalt concrete);
• Construction of stormwater management facilities;
-Excavation of Bioretention cell bottom before placing Bioretention Soil Media;
• Final plat review.
Additional inspections may be deemed necessary as project progresses.
7. After construction is complete and prior to final DCD project approval, the proponent shall submit a letter to
the Public Works Department, certifying that the stormwater management facilities have been constructed per
the approved plans & clarifications. It is the responsibility of the proponent to schedule inspections with the
EOR, his designee &/or qualified inspection firm(s), to provide for said final certification.
cc: JCPW
EnerGov ZONS2023-00013_18