Emergent Weed Treatment Starts Tomorrow

Aquatechnex biologists will be treating Phragmites and Purple Loosestrife along the shorelines of Moses Lake tomorrow (Wednesday August 16) and Thursday August 17th.

The product we will be using is Glyphosate.  This herbicide poses no water use restrictions, water is cleared for swimming, fishing, there are no irrigation restrictions from the treatment.

These applications will not actually enter the water, the material is applied to the foliage on the shoreline.

A map of areas that will be targeted can be found here Treatment Map Link

We will also be reviewing a few other areas and adding them to the map as necessary to meet the needs of the District.

The submerged aquatic weed treatment Phase Two will be next week so check back for information on that.

Moses Lake 2017 Phase Two Starting Next Week

Aquatechnex biologists will be mobilizing to Moses Lake during the Week of August 14th and August 21st to perform 2017 Phase Two Tasks,

During the week of August 14th our team will be targeting emergent noxious aquatic weeds such as Phragmites and Purple Looestrife.  This will not be an aquatic treatment, there are no water use restrictions as this product has none on the label and the herbicide will not be applied directly to the water.

During the Week of August 21st, the Phase Two submerged aquatic weed treatments will take place.  A map will be uploaded shortly that shows the exact locations.  We will also post the exact dates here as this mission gets closer.  There are water use restriction within the marked and mapped treatment zones of 24 hours for swimming and 3 days for irrigation.

Eurasian Milfoil Survey this week

We have noted some Eurasian Milfoil fragments floating in Cascade Region of the lake.  We have not encountered any of this species in the shoreline survey work we have done pre treatment, so we will be performing an aerial survey of the lake to locate any aquatic plant beds throughout the lake and will be ground trothing those locations to confirm species present.  This aerial work will probably be done on Friday of this week with follow up work on Friday or Monday.

Phase One Treatments begin

Aquatechnex biologists have begun the 2017 Phase One treatment for the Moses Lake Irrigation and Rehabilitation District.  Areas of the lake to be treated are first posted with signage at the waterside.  This notice indicated the day to be treated and the water use restrictions.

We are using two herbicides this year the water use restrictions within the treatment area are a 24 hour swimming precaution triggered by the Washington DOE permit, the US EPA requires no swimming restriction.  There is a three day restriction on drawing water from the treatment areas for irrigation starting just as the product is applied.

Please check your waterfront for signs, and review the treatment map page on this web site to see if your property is subject to application.

Tomorrow the areas to be treated will be:

Laguna, Wild Goose, Cove West, Dunes, Parker Horn west shore as noted and the Dredge zone north of the bridge in Parker Horn.

If you have questions you can contact us through the log a case feature on this web site as well.

Please also check back for updates regularly.


2017 Phase One Aquatic Weed Treatments

Aquatechnex biologists have completed survey work for the Moses Lake Irrigation and Rehabilitation District.  We will be treating the week of June 19th and will post exact dates and locations on this web site as the treatment gets closer.

The focus of this treatment will be targeting noxious and nuisance aquatic weed growth in high use areas.  A second treatment a bit later in the summer will target emergent weeds such as Phragmites that are on the State Noxious Weed List along the shoreline.

Go the treatment map page to see treatment zones. You can enter your address at top right corner and determine if you are within the treatment or restriction zone.

Aluminum Sulfate Treatment Pilot Project set for Moses Lake Pelican Horn

As lakes age, nutrients flow in from the watershed where they can start to fuel algae growth.  While treatment of algae can provide short term relief, they are not cost effective on a large scale.  Algaecide treatments are expensive, they kill the algae cells, but the nutrients released go back into the water column and this generates new bloom conditions.  It is also hard to spot treat areas like beaches because wind driven algae from the rest of the lake can move back in rapidly.


One lake management solution is the use of in lake nutrient controls.  An effective technology is phosphorus sequestration treatments.  Sequestering agents such as Aluminum Sulfate can be applied to the water column and the precipitate formed will settle through the water capturing the phosphorus present.  The flocc will then settle on the lake bottom and capture phosphorus releasing from the sediments. 


The Moses Lake Irrigation and Rehabilitation District in conjunction with it’s contracted Lake Management Company Aquatechnex, will be performing a pilot study of this technology in Pelican Horn north of the I-90 Bridge next week.  It is expected that set up will occur early the week and the application will be performed mid week.

Aluminum Sulfate is not a herbicide or algaecide.  It is being applied under a permit from the Washington Department of Ecology.  There are no water use restrictions that will result from this treatment.  Check back next week for exact dates and further information. 

Dealing with Algae

Many lakes including Moses Lake are experiencing increasing levels of blue green algae.  Algae growth is driven by nutrients dissolved in the water column.  Algae as single celled organisms have no root system as a vascular plant has, and the amount of nutrients, especially phosphorus, have a direct impact on the carrying capacity of the lake to grow algae.  In very nutrient rich systems, blue green algae has a competitive advantage because they can fix nitrogen from the atmosphere. 

Nutrients come from many sources.  They can be present in the inflow water, and as Moses Lake receives water from the Columbia River, the quality of the water moving through the system can be a major factor.  There can also be return flow from irrigation delivery systems throughout the Basin upstream from the lake.  While septic and runoff from developed areas can also contribute, they are generally not the major contributor to excessive nutrient loading.  Lastly lakes are a sink for nutrients, the phosphorus that enters the system can accumulate to the point where internal loading is a significant contributor.

Preventing algae growth is problematic in very large lake systems like Moses Lake.  There are a number of algaecides that can provide short term relief, but the Washington Department of Ecology limits these to Hydrothol 191 and Pak 27, a Peroxygen algaecide.

Unfortunately it is not really possible to spot treat algae in areas that are not isolated from the main lake.  Algae is windblown and subject to currents, spot treatments kill the algae present in the treatment zone, but it is often back to pretreatment conditions within a day or so as algae migrates back in. 

Another limitation is that algae treatments kill and break down the cells, they die back, release the nutrients present in their biomass and that drives additional algae blooms, so even in whole lake treatments relief can be short lived, in some cases only a week or two  pass before algae growth fuels back up to problem levels.

Lastly these treatments are extremely expensive for a lake the size of Moses Lake.  Moses Lake is 6,800 acres, one application would cost in excess of $1 million USD and this would probably have to be performed more than a few times per summer.

Nutrient management is potentially a better option.  Materials like Aluminum Sulfate can be applied to capture phosphorus in the water column.  Removing phosphorus removes the carrying capacity to produce algae.  One project we have been involved with is outlined in a video at https://www.youtube.com/watch?v=D0iUtkTVGnc and a second project we work on is a reclaimed water reservoir that has had extensive problems for nearby residents for years, one treatment has brought them through the summer.

This is still a potentially very expensive venture given the size of Moses Lake.  Our team has collected the information necessary to design and propose a demonstration project in the two isolated bays north of I-90 on Pelican Horn.  We will be proposing this to the MLIRD in the next few weeks.  This treatment would be performed in the spring and monitored.  As results were shown, decisions could be made to move to large areas of focus.

There may also be options to inject and treat the inflow water in future years.  The primary problem however may be financial, the size and scope of the operation necessary to clear Moses Lake is driving by the large surface area present.  The demo project should help the region make decisions about expanding this approach.