Clear Lake Integrated Aquatic Plant Management Plan

304 Pages·2004·21.25 MB·English

by  Pamela Francis

COUNTY OF LAKE

WATER RESOURCES
Scott De Leon
255 N. Forbes Street Director
Lakeport, California 95453
Telephone [phone]
Fax [phone]
watershed.co.lake.ca.us

December 19, 2013

Subject: Attachment to Clear Lake Integrated Aquatic Plant Management Plan
submitted as the APMP for the NOI application package for 2013-0002-DWQ

The Clear Lake Integrated Aquatic Plant Management Plan (CLIAPMP), written in 2004 and
its associated Ordinance No. 2777 passed by the Lake County Board of Supervisors in 2006,
will constitute the APMP required by the new Aquatic Pesticide NPDES permit. The
CLIAPMP was the subject of a programmatic EIR in 2004 that was certified in 2006. This
Plan has been the backbone of the Lake County Aquatic Plant Management Program for Clear
Lake since 2004 and has ensured that the application of aquatic herbicides, algaecides and
cyanobactericides to Clear Lake is in compliance with the Clean Water Act.

The CLIAMP dictates that Lake County Department of Water Resources permits all aquatic
plant management (including cyanobacteria) on Clear Lake through its Clear Lake Aquatic
Plant Management Permit that controls individual property owners’, County’s and Cities’
aquatic plant management activities. Water Resources administers the NPDES permit from
the State Water Resources Control Board for discharge of pollutants associated with the
application of aquatic pesticides to waters of the United States, under Water Quality Order
No. 2004-0009-DWQ. The monitoring and reporting requirements of the NPDES are a
transparent method for verifying water quality restoration and protection of beneficial uses of
the receiving waters following a treatment event.

The 2004 NPDES Permit is changing for the 2014 season of aquatic pesticide use. The new
order, 2013-0002-DWQ, has changes that relate to the Lake County Monitoring and
Reporting Plan and Quality Assurance Program Plan. These documents have been updated
and included with the NOI.

When the 2004 NPDES Permit is referenced in the CLIAPMP, this is to be replaced by the
2013-0002-DWQ NPDES Permit and the appropriate monitoring and reporting requirements
for this new permit.

Gates or control structures used in receiving waters
The new permit requires a list of gates or controlling structures in the receiving waters and an
inspection schedule for those gates. This information is absent from the CLIAPMP (although
it has been present in each annual Clear Lake NPDES report).

The CLIAPMP is now amended to add the following.
The controlling gate structure for Clear Lake is the Cache Creek Dam that is owned and
operated by Yolo County Flood Control and Water Conservation District. Clear Lake is a
natural lake and the purpose of Cache Creek Dam is to provide water storage to Yolo County
farmers to be metered out at a controlled rate according to need. The maximum volume of
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water that can be used by Yolo County is approximately thirteen percent of the Lake’s
capacity. The dam is approximately 5.2 miles downstream from the main Lake body (mouth
of Cache Creek) and there is approximately 1,500 acre feet of water between the mouth and
the dam. Lake-wide water samples obtained from the mouth of Cache Creek result in ‘No
Detect’ when tested for active ingredients in the aquatic pesticides used in the County-
permitted program due to the huge dilution of the small portion of herbicide-treated water
with untreated water. This is then further diluted on its way to the dam so that the water at the
gate structure is not impacted by aquatic pesticide applications. The dam’s operation has no
effect on pesticide applications in Clear Lake. The NPDES Annual Report shall continue to
include the Cache Creek dam monthly discharge rate and the lake level using the Rumsey
scale during the aquatic plant management season.

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Clear Lake Integrated Aquatic Plant
Management Plan

August 1, 2004

Lake County Department of Public Works
Water Resources Division
ii
TABLE OF CONTENTS

Acknowledgements
vi

Plan Overview
2

Problem Statement
5

Stakeholder Issues ………………………………….... 5
Hydrilla Program Issues……………………………… 6

Aquatic Plant Management Goals
7

Watershed and Lake Characteristics
9

Watershed Characteristics…………………………… 9
Lake Characteristics…………………………………. 11
Beneficial Uses…………………………………….... 14

Aquatic Plant Characterization
19

Past and Present………………………………….….. 19

Public Involvement
32

Pilot Program……………………………………….. 32
Managing Aquatic Plants Task Force (MAP)……… 33
Clear Lake Advisory Subcommittee……………..… 34

Chara sp. Plant Like Algae

i Clear Lake Integrated Aquatic Plant Management Plan