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Laguna Joaquin Midge Fly UPDATE

There has been a great deal of concern with the Laguna Joaquin Basin from the Community. RMCSD is working to address your concerns, and we have been working collaboratively with other organizations throughout the community to reduce the Midge Fly nuisance and improve water quality. We will use this space to update the Community on Laguna Joaquin and Midge Flies.

Current Information:

Efforts continue by the RMCSD to reduce the Midge Fly populations with continued treatments of the area to kill Midge Fly larvae. Our 6th treatment will take place September 4th, with a 7th treatment to will take place September 18th and 8th treatment on October 2.

Fresh water from the Cosumnes River is continuing to be routed from the Cosumnes River Irrigation ditch in to Laguna Joaquin.

District Staff met with Sacramento/Yolo Mosquito & Vector Control August 27 and discussed Midge Fly Control:

1.       Continue to use the liquid product Vectobac 12 AS, but try to afford more applications within the minimum re-application time of two weeks.  Apply the product as close the bottom as possible.

2.       Consider a partial drain down the level of the water to dry out the banks and mud where the midge larvae live.  This is not always practical as water is so precious.

3.       Request that no fertilizers be added to lawn areas that have runoff into Laguna Joaquin, as they add Nitrogen and Phosphorus on which algae thrive.  Consider removing lawns away from Laguna shoreline that need irrigation and fertilizer and put in hardscape or drought tolerant plantings.

4.       Suggest residents leave their lights off to not attract flying insects.  Leave lights on where people do not congregate or where attraction of insects is not an issue.

5.       Consider trapping systems to monitor the effectiveness of treatments and when treatments may be needed.

6.       Dredge Basin to reduce the amount of mud where Midge Flies could lay their eggs.

District GM is looking into coordinating that dredged material from the basin could be taken to Kiefer Landfill for their trash cover.


August 27, 2020 Update on Laguna Joaquin from Paul Siebensohn, Director of Field Operations Rancho Murieta Drainage - Laguna Summary Description


Historical Information:

2016 Memo Discussing Midge Flies1998 Discussion From Former Director of Field Operations Lee Lawrence1998 Storm Drainage Master PlanFolsom & El Dorado Basins for comparison with Laguna Joaquin