10/31/2022 - Lake Quality Dashboard

BVSA provides the data for your convenience, but please determine your own personal risks/conditions and the fact that this is an unsupervised area and natural water body. During the summer, this information can fluctuate rapidly based on water temperature and usage.

The link to the state website is here: https://mywaterquality.ca.gov/habs/where/freshwater_events.html

Lake measurements are taken every 2 weeks during April through September. E.coli and Cyanobacteria are tested as necessary based on water appearance and previous test results.

10/19/2022 - Buoys & Hoop Nets at Four Island Lake

In an effort to remove invasive Bullhead Catfish the Lake Quality Advisory Committee (LQAC) has placed hoop nets in Four Island Lake.  The LQAC is asking that residents please stay 30’ away from the buoys on the North West side of Four Island Lake near the dam.  The shaded red area in the image below is where the net is currently located.  If you have any questions please email the LQAC at BVLQAC@gmail.com.

10/14/2022 - Electrofishing Project Postponed

Due to a delay with the California Department of Fish & Wildlife, our electrofishing permit has been delayed. The lakes will not need to be closed next week.

10/4/2022 - Cub Lake & 4 Island Lake to be closed Monday, October 17 & Tuesday, October 18

The Lake Quality Advisory Committee has scheduled a pilot electrofishing project for Monday, October 17th and Tuesday, October 18. No water access will be available including boating, fishing, paddling, and swimming.

Electrofishing involves a placement of a electrical current in the water to temporarily stun fish to measure and harvest catfish. This pilot project is intended to determine the effectiveness of electroshocking as a control measure for two recurring problems within our lakes:

1) Invasive bullhead catfish (please see post below about the problem with catfish in our lake related to this summer's fish die off)

2) Long term selective harvest of desirable species to keep fish populations within balance.

There will be no lasting effects to the water, and the lakes will re-open as usual on Wednesday, October 19th for regular access.

If you have any questions, please contact the Bear Valley Lake Quality advisory committee at bvlqac@gmail.com.

9/26/2022 - Lake Quality Dashboard

BVSA provides the data for your convenience, but please determine your own personal risks/conditions and the fact that this is an unsupervised area and natural water body. During the summer, this information can fluctuate rapidly based on water temperature and usage.

The link to the state website is here: https://mywaterquality.ca.gov/habs/where/freshwater_events.html

Lake measurements are taken every 2 weeks during April through September. E.coli and Cyanobacteria are tested as necessary based on water appearance and previous test results.

9/19/2022 - LQAC is seeking Fishing Volunteers for Cub Lake

The Lake Quality Advisory Committee would like to advise the community that they will be sampling/harvesting fish with a boat from Cub Lake over the next month. The LQAC will be using traditional angling techniques from the boat as part of this process. So please don’t be alarmed when you see the LQAC boat fishing within Cub Lake.

The LQAC is seeking community volunteers to assist with this process. If you would like to volunteer and have the opportunity to fish Cub Lake from a boat, please contact bvlqac@gmail.com. If you volunteer a release form will be required. Children are encouraged to participate but will also require a supervising adult to be present.

9/2/2022 - LAKE QUALITY DASHBOARD UPDATE

At this time, the prior Caution tier has been removed :)

BVSA provides the data for your convenience, but please determine your own personal risks/conditions and the fact that this is an unsupervised area and natural water body. During the summer, this information can fluctuate rapidly based on water temperature and usage.

The link to the state website is here: https://mywaterquality.ca.gov/habs/where/freshwater_events.html

Lake measurements are taken every 2 weeks during April through September. E.coli and Cyanobacteria are tested as necessary based on water appearance and previous test results.

Frequently Asked Questions about the Four Island Lake Fish Die Off (7/22-7/25)

Why did the fish die off happen?

In order to understand what is happening within the ecosystem of the lakes, we need to understand biomass and carrying capacity. Biomass is the amount of living organisms within a given area or volume. Carrying capacity is the amount of living organisms that can safely reside within a given area or volume. When the biomass is higher than carrying capacity, catfish outcompete the desirable fish for the available oxygen. Low oxygen levels are caused by naturally occurring algae bloom/die off cycles.  

Based on guidelines established by the University of California Davis, the fish carrying capacity of Four Island Lake is between 2,600 lbs. (low fertility) and 10,400 lbs. (high fertility). After the fish die off in 2019, the consultants had very little data to estimate the number of catfish. It was assumed that it was approximately 10,000+ lbs. after the 2019 fish die off.  Unfortunately, we now know that number was gravely underestimated.  It is conservative to say we have at least 20,000 lbs. of catfish within Four Island and the true number is much higher, possibly as high as 40,000 lbs.  It is estimated that 6000 lbs. of fish were removed in the recent die off incident which makes it easy to see where the problem lies. We are at least 2.5 times the highest and 10 times the lowest recommended carrying capacity of the lake.  The catfish simply outcompete the desirable fish for oxygen and deplete all of the available oxygen resources because catfish can survive in lower dissolved oxygen levels.  Our consultant now believes that this has been an ongoing problem and significantly contributed to the last fish die off that occurred in 2019 and previously.  

What is an algae bloom?

The LQAC is working with the BVSA and the California State Water Board to prevent, monitor, and communicate algal blooms in our lake. Cyanobacteria, sometimes called blue-green algae, are found in all types of water. Cyanobacteria grow quickly, or bloom, when the water is warm, stagnant, and full of nutrients. Blooms may not be visible if they are below the surface, or may appear as foam, scum, or mats on the surface of the water. During a bloom, algae grows and produces massive amounts of oxygen during the day and then consumes massive amounts overnight, which is why the fish die off was noted in the early morning hours.  Sometimes, cyanobacteria blooms produce toxins. Swallowing water with cyanobacteria toxins can cause serious illness in people, pets, and wildlife.

The LQAC regularly checks the water at Four Island Lake for cyanobacteria and related toxins. Findings are reported to the BVSA and the State of California.  

On 7/13, our morning dissolved oxygen (DO) was at 5.95 mg/l. The evening reading was 12.48 mg/l. A large amount of cyanobacteria had been present on the surface of the water that week. The DO, and cyanobacteria test results support that we were in an algae bloom.

There are reports that someone was spraying the shore around Four Island – did this cause the fish die off? Are we treating the lakes?

The BVSA has emphasized water quality suitable for public safety as a top priority to ensure that the lake is open and safe for recreational activities. Many of our efforts when the LQAC was formed have been focused on reducing the unwanted nutrients within the lake (ex. lily pads, floating islands, Phoslock, etc.). However, low levels of dissolved oxygen are also an issue in stabilizing the complicated ecosystems of our lakes. Earlier this year, we had contracted with Marine Biochemists to treat both Cub and Four Island lakes bi-weekly.  Marine Biochemists are licensed, certified and insured aquatic applicators.  These applications would include algicides, dyes, and enzymes as needed. As part of the contract, Marine Biochemists is also responsible for obtaining any required permitting. Based on the results from 7/13, we contacted our vendor Marine Biochemists to focus on reducing the algae and cyanobacteria at their next scheduled treatment date on 7/19. On the day of this treatment, the DO was 3.06 mg/l which is very low and a significant decrease from 7/13, indicating a natural algae die off was already occurring.  Marine Biochemists treated the lake with Copper Sulfate, following appropriate application protocols and guidelines.  

The fish die off occurred due to an extreme overabundance of catfish biomass outcompeting the desirable fish for available oxygen within Four Island Lake. The low oxygen levels were caused by a naturally occurring algae bloom/die off cycle. It was not due to the routine algicide application. One of our top priorities is a safe water quality environment for our residents. Water treatment to control cyanobacteria is part of that plan.

Is Four Island safe to swim and boat?

Based on the lab results and visual appearance, Four Island remains in the Caution Tier - the lowest of the three tiers the state issues. Based on this tier, the state recommends the following:

-You can swim in the water but stay away from algae or scum in the water.

-Keep children away from any floating algae in the water or shore.

-Do not drink the water or use it for cooking.

-Do not let pets drink the water or scum in the shore.

 

BVSA provides the data for your convenience, but please determine your own personal risks/conditions and the fact that this is an unsupervised area and natural water body. During the summer, this information can fluctuate rapidly based on water temperature and usage.

The link to the state website is here: https://mywaterquality.ca.gov/habs/where/freshwater_events.html

Lake measurements are taken every 2 weeks during April through September. E.coli and Cyanobacteria are tested as necessary based on water appearance and previous test results.

How many aerators are in Four Island Lake?

We currently have 16 aerators within Four Island. More aerators would be useful. In an effort to minimize the effect on the budget, we will be adding an additional aeration system to the next reserve study which would allow us to put off purchasing them until the funds are set aside in the next 3-5 years. Given the biomass issues we are facing, an additional aeration system would have only saved more catfish. We ultimately will need an additional system, but the catfish must be dealt with first.

Why didn’t the fish at Cub Lake die?

Based on data collected in June, Cub Lake would have had a fish die off if the BVSA Board of Directors had not intervened and directed staff and outside consultants towards implementing preventative measures. Cub Lake is generally sampled, treated, and managed the same as Four Island Lake. The main difference between the two lakes is that Cub does not have the extreme catfish biomass problem. With fewer catfish, the desirable species are able to survive lower dissolved oxygen periods for short amounts of time. At this time, we believe this is primarily due to predation from adult largemouth bass and channel catfish which are species currently absent from Four Island Lake.

 Why don’t we just drain and deepen Four Island Lake?

Four Island Lake is the primary irrigation source for the Oak Tree Golf Course. As such there must be water at least 5 feet deep within the lake from April through October. During the winter non-irrigation months, the lake collects runoff and fills. This runoff is water that is collected at no cost to the BVSA members and supplies most of the water for the golf course during the months of April-July. If the lake is drained it takes time (months) for the bottom to dry to the point that heavy machinery can safely operate on the lake bed. Since we cannot have the lake drained for this period of time due to irrigation and water collection needs there is no easy, effective way to drain and deepen Four Island Lake.

 What is the plan going forward?

Biomass of catfish is our largest challenge, and until we bring it under control, we will be fighting a losing battle.  Multiple plans have been presented to our General Manager and Board of Directors by our consultant. These ideas will be discussed at the next Lake Quality Advisory Committee Meeting. Currently, the most viable plan appears to be that around November, we would pump water from Four Island upstream into Jacks Hole and Cub Lake.  This will reduce water levels in Four Island which will make it easier to harvest the catfish biomass out of the lake using seine nets.  

Though it sounds counterintuitive, some good did come from this fish die off. In the course of removing the fish from the die off and noting the various sizes, we were able to receive insight that our fish stocking program and overall fish management plan was working as planned. It’s very rare and expensive to gain this kind of information. For example, 4” large-mouth bass that were introduced in January 2021, had achieved growth to 16” by July 2022.  This is better than anticipated growth.  Additionally, the 7th hole hatchery pond still has bluegill, green sunfish, and golden shiners which can be harvested and transplanted so BVSA still has a way to reduce the overall stocking costs once the catfish biomass issue has been resolved.

 I have more questions. OR I want to be involved in what the Lake Quality Advisory Committee is doing.

Members are welcome to contact the LQAC via email at bvlqac@gmail.com.  There are also monthly Lake Quality Advisory Committee meetings. The next meeting is scheduled for this Monday, August 1st at 6pm at the Whiting Center. Members can also join the meeting via zoom.Details will be on the agenda posted  days to come.

Lake Quality Dashboard

Lake measurements are taken every 2 weeks during April through September. These results will be consistently posted on this site at www.bvsa.org/amenities/lakes. BVSA provides these data for your convenience, but please determine your own personal risks/conditions and the fact that this is an unsupervised area and natural water body. During the summer, this information can fluctuate rapidly based on water temperature and usage.

07/27/2022 - The cyanobacteria "Caution" tier is the lowest of the three that the state issues. There were no detectable toxins present in the water but cyanobacteria was identified on a microscope analysis which triggered the caution level.

The next cyanobacteria sample will be sent into the lab next week. The BVSA has also contracted with a company to begin treating the water at both Cub & 4 Island every 2 weeks during the summer months to keep the lakes as healthy as possible.

The link to the state website is here: https://mywaterquality.ca.gov/habs/where/freshwater_events.html