A9_Water_Quality_Monitoring_Plan.pdf

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Water Quality Monitoring Plan Coos Bay Upriver Clamshell Dredging 2019

This monitoring plan is to ensure compliance with the terms and conditions of the National Marine Fisheries Service’s (NMFS) May 25, 2017 biological opinion (BiOp) and the Oregon Department of Environmental Quality (DEQ) March 31, 2015 Clean Water Act (CWA) Section 401 Water Quality Certification (401 WQC) for the operations and maintenance dredging program at the Oregon Coastal Projects.

Turbidity monitoring must be conducted during all dredging operations at all of the Coastal Projects during daylight hours. When dredging in areas of greater than 20% fine-grained sediments (equal to or greater than 20% silts/clays) monitoring shall be conducted using a turbidimeter.

The monitoring standards are slightly different within each document, so the more conservative conditions in the DEQ 401 WQC will be used to satisfy the requirements of both agencies in all instances except when dredging sediments that contain greater than 20% fine-grained material.

Visual Monitoring. Not available for dredging at Coos Bay River Mile 11+49 to 15+00.

Metered Monitoring. In areas where sediments contain greater than 20% fine-grained material, a turbidimeter shall be used to quantify change in turbidity as nephelometric turbidity units (NTUs). Readings will be taken during daylight hours at monitoring points 200 feet upcurrent (representative background), 200 feet downcurrent at mid-depth (compliance point) during dredging operations. If a visible plume is present, the compliance point shall be within the plume and compared to the background reading. The compliance point will be located no more than 200 feet downcurrent of the most downcurrent discharge point (bucket or scow if the scow has skimming capability).

Compliance readings will be recorded every two hours during in-water work. If a 10% exceedance of the background level occurs at 200 feet downcurrent of the discharge point, implement measures to reduce turbidity, including, but not limited to, the measures identified in the 401 WQC or BiOp and continue monitoring every two hours. If exceedance occurs with two consecutive measurements (a total of two monitoring events over four hours), the activity causing the turbidity must be stopped until the problem is resolved.

The exceedance standard in the 401 WQC is more restrictive than the conditions identified in the NMFS’ BiOp, therefore, prior to exceeding the standards identified in the NMFS’ BiOp, the 401 WQC standards would already have to be exceeded. Nonetheless, should turbidity levels exceed 30 NTUs above background for two consecutive two-hour samples, or 50 NTUs or more above background for any sample, work must cease for the remainder of that 24-hour period. The 24-hour period is defined as sunset to sunset.

Recordkeeping and Reporting. The date, time, and location of the dredging (project name, reach or river mile, coordinates, name of dredge), background, and compliance points for each sample shall be recorded on the provided spreadsheet. The tidal stage (incoming, outgoing, slack), published sunrise and sunset times, and other pertinent weather information shall be recorded. If conducting visual monitoring, the presence or absence of a visible plume shall be noted. Actual

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NTU readings shall be recorded for metered monitoring. The Operations Branch of the Portland District will receive the daily turbidity reports from the dredge and review for completeness.

Operations will post the daily reports to the server for Environmental Resources Branch retrieval and monthly submittal to NMFS.

A Project Completion Report shall be prepared and submitted to NMFS by February 15th each year by the Environmental Resources Branch of the Portland District. The report shall describe the Corps efforts in carrying out the proposed action and the success in meeting the terms and conditions contained in the biological opinion. The following information must be provided in the Report:

(1) Project name and description of specific work carried out (e.g. entrance channel, navigation channels, access channels, etc.).

(2) Project manager name and contact information.

(3) Contractor (if any), name and contact information.

(4) Dredge type (hopper, pipeline, mechanical).

(5) Start and end date of dredging.

(6) Turbidity monitoring log.

(7) And up-to-date Sediment Analysis Plan and PRG Final Technical Memorandum prepared as described in the SEF (Corps et al. 2009).

(8) Volume of dredged material.

(9) Disposal area used.

(10) Annual bathymetric surveys of in-water disposal sites.

(11) Description of non-sediment debris, i.e., logs, wood, other large materials, during dredging and how that material was dealt with.

(12) Any other information the Corps deems necessary or helpful to assess habitat trends because of actions authorized under the NMFS BiOp.

Project Information

Third Party Contacted (check one) Contact Information

541.756.0135

541.267.6981 (use only when the CGC Orcas is moored/in port)

Criteria in Question

Title Name Decision (Monitoring is Safe or Unsafe)

Notes

Wind (kts. Steady and gusts)

SW OR Regional Airport Recorded Local Weather Message USCGC Orcas Watch Stander

Date & Time Monitoring Vessel Location(s) & action(s) Tide state (ebb and/or flood)

Visibility (miles)

Third Party Confirmation of Local Weather Conditions that would prevent WQ Monitoring

Wave Height (feet) Current (kts.)

Precipitation (type)

Dredge Captain Launch Operator Third Party