KENNEWICK -- It's a war against algae and weeds in the Kennewick Irrigation District, and a new weapon will be entering the fight Monday.
The flush of hot weather has brought on a big bloom of algae in district canals, making it difficult for KID's vegetation attack team to keep up using its conventional chemical arsenal.
"We are using a new chemical -- endothall -- starting Monday," said Beth Smith, KID's public information officer.
Mike Pearce, KID's chemical coordinator, said endothall will supplement a copper-based product that also is introduced into the canal water to help beat back algae and aquatic weeds.
The concentrations that will be used should not affect crops or lawns, KID said.
This is the first year for using a liquid form of copper as a liquid algaecide, and it is the first time endothall has been registered by the Department of Ecology for KID's herbicide permit.
This time of year Pearce is up before dawn and cruising canal access roads, periodically dispensing the liquid copper where there are known areas of algae production.
"Algae typically occurs where water ponds up and slows and where shallow water warms up," Pearce said.
While algae buildup is a frequent summer problem for KID customers, it can be aggravating particularly when heat comes on quickly and the algae explodes.
KID staff first saw large quantities of algae in canals in late June. There was so much of the mossy green stuff that some customers had low water pressure, and plugging was occurring in pump stations and agricultural weir boxes, Smith said in a news release.
Smith said KID has had two of its seasonal maintenance crew members going from trouble spot to trouble spot, cleaning screens all this week.
But when endothall is put into the water next week, the algae should abate significantly within a couple of days and it will be effective on pond weeds for two months or more, Pearce said.
"We're supposed to be able to treat the entire canal system with one application at the head end of the canal system," Pearce said.
Smith said another KID employee has been trained as a chemical applicator to work with Pearce to put more manpower into battling algae.
Using the chemicals also requires KID to sample the water frequently to ensure the chemical load is correct and complies with Ecology's permit, Pearce said.
For more information about endothall, go to www.epa.gov/safewater/pdfs/factsheets/soc/endothal.pdf.
-- John Trumbo: 582-1529; email@example.com