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Citizen group demands Thurston County drop toxic algae treatments at Black Lake

Prompted by the Black Lake Special District’s (BLSD) recent request to the Thurston County Commissioners that they back a bond for $1.4 million to apply alum as a measure to counter toxic algae overgrowth, a group of citizens who live around the lake and other environmental advocates formed Citizens for a Clean Black Lake (CCBL), writing the Commission to urgently request that a full environmental review be done before any treatments of alum, glyphosate or diquat occur.

Contradicting the District’s understanding of the lake’s environmental health, the group points to several studies, one of which the County participated in which links Black Lake’s continuing pollution problems to ongoing damage from prior spraying, faulty septic systems, stormwater runoff, and agricultural practices that cause excess phosphorus levels in the lake.

Commissioner Tye Menser’s response to the group’s first letter provoked a second, more pointed response (all three letters appear in full at, questioning the District’s jurisdiction over Black Lake and the hidden costs to taxpayers if the bond goes into default.

Who has the legal authority to do this project on Black Lake?

The BLSD was formed under RCW 83.58.010, which sets up flood control districts, but BLSD’s stated aim for this project is for recreational purposes for boaters and swimmers and has nothing to do with flood control under this law. The group notes that DNR (Department of Natural Resources) owns the lake, Washington Department of Fish and Wildlife (WDFW) operates a public boat launch and stocks the lake with fish, the County owns 2 parks on the lake, and the area is within Tumwater’s Urban Growth Area and the City of Olympia.

In 1986 the Department of Ecology (ECY) established a groundwater reservation under RCW 90.54.050 that encompasses Black Lake which requires the County to coordinate with other jurisdictions in the area to “protect the quality of the groundwaters of the state.” Clearly, any actions taken must include coordination with these state agencies and municipalities. The group notes “Thurston County does not have the discretion to abrogate its authority and choose not to enforce this law…It must complete an environmental review in coordination with DNR, ECY and WDFW before any further actions are taken.”

CCBL notes extra jurisdictional impacts there also call for an environmental review (citing Save a Valuable Environment vs. Bothell, a Washington Supreme Court finding).

Who ultimately pays?

In his reply to their first letter, Commissioner Menser states that public funds will not be used to pay for the treatment. In their reply, Citizens for a Clean Black Lake says the public will, indeed, be responsible:

“In fact, the County will be lending its credit by guaranteeing a bond for $1.4 million. Will the County condemn the property on the lake if the bond is not repaid? Using public credit is no different than using public funds. The County cannot back a project undertaken without the proper authority. They cannot back this project because it is not a flood control project. Doing so would be a theft of public resources.”

Die-off, degradation, deterioration

The group is particularly opposed to the BLSD Board’s unlawful plan to apply herbicides and alum to the lake and challenges the authority of BLSD to do so, noting its impact on other state wildlife initiatives:

“… As noted above, Black Lake belongs to DNR. Washington Department of Fish and Wildlife (WDFW) operates a year-round boat launch and stocks the lake with Rainbow Trout in addition to the naturally reproducing Coastal Cutthroat Trout, and other species in the lake, all of which could be killed by an alum treatment.”

The letter continues by questioning the safety of the proposed alum treatment, noting that Wapato Lake, Green Lake and Heart Lake “all experienced notable fish kills as a result of their alum treatments.” Using findings from these treatments, they note that the general ECY permit guidelines for safety do not adequately protect aquatic life and that by increasing water alkalinity over time, alum ultimately increases phosphorus levels, compounding the problem.

Alum treatment, the group asserts, is a temporary fix, at best, for a problem that’s been decades in the making. And because Black Lake receives continuing septic system effluent and nutrient polluted ground and surface water, the alum treatments would have to be repeated frequently. Ultimately, they write, “ this treatment will do absolutely nothing to restore the health of the ecosystem basin, the quality of surface and groundwaters flowing from the lake, the viability of its habitat, or its beneficial use for recreation as required by provisions of the Federal Clean Water Act, State enacted RCWs and approved WAC (laws). On the contrary, chasing one chemical treatment after another will undoubtedly degrade the life and integrity of the ecosystem and will continue to create a compost pile of nutrient load from the deteriorating vegetation caused by these chemical treatments.

“Besides the poisons glyphosate, diquat dibromide, endothall dipotassium salts and others, regularly applied by the BLSD to control aquatic weeds which pose their own serious risks, we do not know how much and what other chemicals are entering the lake from leaking septics, agricultural practices and stormwater runoff… Within this bubble of ignorance, it would be foolhardy to go forward with this short-sighted proposal without a full environmental review.”

A plea for saving a beloved lake

The letter ends with a plea to commissioners to act immediately to establish an on-site septic monitoring system similar to one in Henderson Inlet and a warning against using public money to poison a public waterway.

“We question your Staff’s assertion that they believe the alum treatment is a reasonable short-term strategy to buy time while the County addresses the longer-term phosphorus loading issues… Hundreds of thousands of dollars have already been wasted on short-lived ‘solutions’. Is it rational or fiscally responsible for the County to use its credit to back an assessment bond that throw millions more at a temporary, risky dead-end ‘treatment’ when that money could be spent to help residents upgrade their septics or connect to sewers? Absolutely not! This is 2020. The time to deal with this is NOW.”


Citizens for a Clean Black Lake

To volunteer with Citizens for a Clean Black Lake, contact Suzanne Kline at


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