This short video from AquaTechNex shows an example of the alum treatment process on Canyon Lake in southern California. Alum application in Canyon Lake was proposed in order to remove nutrients from the water column that contribute to algal blooms in the lake. By binding phosphorus and reducing algae growth, the continued use of alum is expected to reduce nutrient cycling and associated sediment oxygen demand in the lake sediments. The goal is compliance with the interim and final chlorophyll a TMDL targets. Alum application is also anticipated to indirectly increase dissolved oxygen in the hypolimnion as well as reduce the frequency of ammonia toxicity.
The Black Lake Special District will not be holding their regular meeting on December 18, 2015. The next meeting will be held on Monday, January 11, 2016 at 5:30 pm.
Please click here for a news release from Thurston County Public Health and Social Services regarding a swim advisory due to toxic algae blooms.
Please see below for an announcement from Black Lake Special District of an apparent successful bidder for management and oversight of an alum treatment.
The Black Lake Special District will be holding a special meeting on Tuesday, October 27 at 8:30 am in the OrgSupport Offices, 1520A Irving St SW, Olympia, WA 98501.
The Black Lake Special District is requesting proposals for the oversight and management of an Alum Treatment. More information can be found here.
Please feel free to view the recorded work session from June 4, 2015 HERE.
Black Lake Special District
To: Black Lake waterfront property owner
Our permit for weed harvesting was finally approved on 9/16, 64 days after the start of the approval process. At this late date, we will not proceed with harvesting as the Najas (or water nymph) will be dormant within the next few days. The permit does allow us to harvest from 7/1 to 9/30 for the next five years. We are also allowed to cut and remove the fragrant white water lily during the same cutting period. You can see the full permit and its provisions at Blacklakespecialdistrict.org.
A work group is forming to look into solutions for algae blooms. If you would like to participate please email us at email@example.com or call (360) 867-8814.
Letters of Concern
A letter has been sent to Thurston County expressing concern about the maintenance of the Black Lake Ditch. The ditch is becoming choked with vegetation and beaver dams have reappeared. Flooding of lower elevation properties can occur this winter.
Fish Pond Creek, a major water source to Black Lake, is reported to have high levels of fecal coliform. A letter was sent to Thurston County and the City of Tumwater; we want to better understand the problem and what is or can be done.________________________________________
Back Lake Algae Sampling, Testing and Health Alert Advisories
as of October 2014
Sue Davis with Thurston County’s Environmental Health described the processes as follows:
* Thurston County is required to follow the Washington Department of Health testing and alert
* When Environmental Health is contacted about an algae bloom, staff take samples in areas with the
highest concentrations of algae.
* The samples are FedEx’ed to a lab in King County. Results are made available in 5 days. The delay
is largely due to the testing process. If the sample shows harmful toxin levels, a Health Alert Advisory
* Samples are taken and tested once a week following a health alert. When two successive weeks
show toxin levels to be safe (or algae has dissipated), the Health Alert Advisory is lifted.
* The minimum period for a Health Alert Advisory is usually 3 weeks.
* Many areas of the lake where algae is not present are safe during a Health Alert Advisory.
* Areas of the lake with algae should be avoided even when a Health Alert is not in effect.
* Algae testing results for Washington lakes can be found at: https://www.nwtoxicalgae.org/Data.aspx
The toxin level for microcystin was 162 micrograms/L in a sample collected on July 29, 2014, which is above the safe level. The state recreational advisory level is 6 micrograms.
Here is an article that describes what toxic algae is and why it’s a health risk. Just bathe yourself and your animals after going in the lake. http://www.co.thurston.wa.us/health/ehadm/swimming/pdf/BGAlgae.pdf