A copy of the current Aquatic Plants and Fish
pamphlet available from the department shall serve as an HPA, unless otherwise indicated, and be on the job site at all times. Bottom barriers or screens are useful for eradication of an aquatic noxious weed early infestation. Bottom barriers or screens are best used in small, confined areas where control of all plants is desirable. Bottom barrier or screen projects may incorporate mitigation measures as necessary to achieve no-net-loss of productive capacity of fish and shellfish habitat. The following technical provisions shall apply to bottom barrier or screen projects for both aquatic noxious weed or aquatic beneficial plant control or removal except where otherwise indicated:
(1) Due to potential impacts to sockeye spawning areas, prior authorization by the department shall be required for activities in Baker Lake and Lakes Osoyoos, Ozette, Pleasant, Quinault, Sammamish, Washington, and Wenatchee. Authorization may or may not be given for the activity, and if given, may require mitigation through a written agreement between the applicant and the department for impacts by the activity to the spawning area.
(2) For removal and control of aquatic noxious weeds, bottom barrier or screen material shall not cover more than fifty percent of the length of the applicant's shoreline. Bottom barrier or screen projects covering a larger area shall require prior authorization by the department. Bottom barrier or screen and anchor material consisting of biodegradable material may be left in place. Bottom barrier or screen and anchor material that is not biodegradable shall be completely removed within two years of placement to encourage recolonization of aquatic beneficial plants unless otherwise approved by the department.
(3) To remove or control aquatic beneficial plants such that an access is maintained for boating or swimming, bottom barrier or screen and anchor material that is either biodegradable or nonbiodegradable may be installed along a maximum length of ten linear feet of the applicant's shoreline. Bottom barrier or screen projects for boating and swimming access which cover a larger area shall require prior authorization by the department.
(4) Bottom barrier or screen material shall be securely anchored with pea-gravel filled bags, rock or similar mechanism to prevent billowing and movement offsite.
(5) Bottom barrier or screen and anchors shall be regularly maintained while in place to ensure the barrier or screen and anchors are functioning properly. Barriers or screens that have moved or are billowing shall immediately be securely reinstalled or removed from the watercourse.
(6) Existing fish habitat components such as logs, stumps, and large boulders may be relocated within the watercourse if necessary to properly install the bottom barrier or screen. These habitat components shall not be removed from the watercourse.
(7) If at any time as a result of project activities or water quality problems, fish life are observed in distress or a fish kill occurs, operations shall cease and both the department and the department of ecology shall be notified of the problem immediately. The project shall not resume until further approval is given by the department. Additional measures to mitigate impacts may be required.
(8) Every effort shall be made to avoid the spread of plant fragments through equipment contamination. Persons or firms using any equipment to remove or control aquatic plants shall thoroughly remove and properly dispose of all viable residual plants and viable plant parts from the equipment prior to the equipment's use in a body of water.
[Statutory Authority: RCW 75.08.080. 97-13-001 (Order 97-84), § 220-110-333, filed 6/4/97, effective 7/5/97.]