Moses Lake Irrigation & Rehabilitation District (MLIRD)

Moses Lake, Washington


ILA # 14-242

Bulletin Board

2014 Treatment Maps

2014 Treatment Timeline

Riparian treatment starts
this week July 21, 2014
on the upper lakes to include Blue Lake

Riparian work continues this week on private properties

Moses Lake
July 8, 2014 – July 11, 2014

Upper Lakes Area (to include Blue Lake, Alkali Lake, Lenore Lake)

July 7, 2014 and July 21, 2014
July 25, 2014

Check back for updates.



Riparian Herbicide Treatment Letter

Lakeland Treatment Notification Letter

MLIRD Treatment Notification Letter


call (877) 273-6674

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Project Introduction

In the spring of 2014, a grant was awarded to Moses lake Irrigation and Rehabilitation District. The purpose of this grant is to expand on a treatment completed in 2012 to control invasive upland and riparian plants. Target plants are Phragmites Australis, Yellow Flag Iris, Purple Loosestrife, Reed Canary Grass, and Tree of Heaven. Incidental infestations of Japanese Knotweed and Kochia will also be treated if the infestation was in proximity to the target plants.


Moses Lake is a 6,800 acre (surface area) water body with approximately 120 miles of shoreline, and is located in Grant County, Washington. At a water surface elevation of 1,047 feet, the depth ranges from 2 to 35 feet deep. Moses Lake’s watershed is inclusive of portions of Lincoln, Adams, Grant, and Spokane Counties and receives perennial flows from Crab Creek and Rocky Ford Creek. Rocky Ford Creek contributes substantial flow but is a spring-fed stream with very small surface drainage area.

The Moses Lake Irrigation and Rehabilitation District (MLIRD) has the responsibility to maintain and enhance the water quality and usability of this fresh water reservoir. In 2008, the MLIRD conducted a lake-wide survey to map the characteristics of the lake including aquatic vegetation diversity and density, sediment types, and depths.

In 2009, the MLIRD created an Integrated Aquatic Vegetation Management Plan in order to define the survey data and discuss current and proposed management techniques, including chemical control. (Attached, see appendix A – Moses Lake Overview Map)

The survey team also recorded a large number of shoreline invasive species. In 2010, the decision was made to implement an herbicide control project of approximately 330 acres of aquatic plants. During a multi-agency meeting with the MLIRD, Grant County Weed Board, and Washington Department of Natural Resources, it was agreed that a separate herbicide control project for the shoreline plants would be implemented immediately after the aquatic treatment; the 2011 treatment followed this protocol.

The 2012 treatment also followed this protocol and included additional treatment areas; The Grand Coulee Lakes including: Park Lake, Blue Lake, Dry Falls, Soap Lake and Alkali Lake. New treatment areas were based on surveys conducted in 2011.

2014 Treatment Areas

gc2Maps from the 2012 treatment areas will be used as guidelines for the 2014 application area. The 2014 treatment areas will be expanded from the 2012 treatment areas once those areas have been treated and surveyed.

Project Preparation


In preparation for the 2014 project an 18 foot airboat will be fitted with a 300 gallon sprayer system with a 5-hp Honda motor and a hypro pump. The system has a hose reel with 300feet of hose and is equipped with 1 spray gun.
A spray gun will be used to spray along the shoreline to ensure good coverage of the plants. The same application system will be used on a Ford F350 as well and back packs as needed in the areas a vehicle cannot access.

Spraying Phragmites around Moses Lake