How to resolve AdBlock issue? The lake levels are rising and while it’s going to make for an amazing summer with fishing and boating, right now we are concerned about flooding in our channel. What resources are out there? What about debris like logs and docks or other floating hazards in the Lake?
Thanks!
- Falerie in Finley
Dear Falerie,
What a great set of questions! Also, you are not the only one who has asked about lake levels, flooding and debris. These are all timely topics so I will provide some details and additional resources for each one.
Firstly, let’s revisit the way Clear Lake water level is measured, using the Rumsey Gage. Daily lake level data is measured from an in-lake gauge (#11450000) operated and maintained by the United States Geological Survey (USGS). The gauge has historically been located on a pier at Lake County Vector Control District in Lakeport, but is sometimes relocated during low water, like our past drought events required the gage to be moved to another dock location at Lakeport Library park.
Right away let me address the gage issue; I have received many, many emails providing me the right gage/gauge to use. Here are some gauge facts: the vernacular use of “gage” and “gauge” can be used interchangeably and both can be used as a verb or a noun. Technically, the word “gage” is a different word altogether (it means to throw down a challenge, like a knight proposing combat). But while knighthood battles are mostly extinct, the word “gage” is still maintained in the English language. The USGS has a historical affinity for the use of “gauge”, but more recently uses gage (see the graphic below and “Rumsey Gage”). According to Merriam-Webster Dictionary, considering global use, “gauge” is the preferred variant of this word and is more commonly used than “gage”. According to ESL.com, the word “gage” is becoming obsolete. Even as I type this, my spellcheck autocorrect wants to change the “gages” to “gauges”. If you ask the Lady of the Lake, life is too short to gauge your success by the amount and type of gages being counted, but don’t mind me and pick the gauge/gage that is right for you!
It makes sense that Vector Control would be good partners for a lake gauge as low and high water levels influence habitat availability for mosquitos. Also, believe it or not, before the internet, folks would call into the Vector Control District and ask for the current lake levels; now they are simply a few clicks away on your computer or smartphone!
The lake level data is available online in graph or tabulated format at the USGS Clearlake Lakeport CA station.
Figure. Lake Level data for the last 4 years (Jan 2019 - March 2023). Orange line depicts the average lake level over the last 103 years. Red solid line demonstrates the flood stage at 9 ft.Rumsey (while listed in the legend, there is no estimate gauge height depicted on this graphic). Blue line is the actual recorded gauge height. Source: USGS
Data is available for other stream, lake, and reservoir gauges around the state. I suggest you explore the Sierra Nevada River Forcast Network Interactive Map. On this site, you can find different lakes or rivers with real-time gages measuring lake levels, stream height and stream flow.
Also, the Lake County Water Resources Department monitors the daily lake level and can provide that to you by phone at 707-263-2344, if you do not have access to the website.
Determining Lake Level
Clear Lake is different then every other lake, reservoir, or water body out there when it comes to the lake level measurement method. Clear Lake uses the “Rumsey Gage” unit of measurement. This measurement was established by Captain Rumsey in 1873. The measurement was derived from the natural levels of the lake as determined by the Grisby Riffle, with a range between zero and 7.56 feet Rumsey, which is the natural low and high levels of the lake. For example, the low level at “zero rumsey” is the point at which water is too low to pass the Riffle and flow down Cache Creek; it’s the “natural low” level of the lake.
Unlike reservoirs, Clear Lake’s water level is naturally controlled by the Grigsby Riffle. The Grigsby Riffle is a naturally formed rock gravel formation at the confluence of Cache Creek and Seigler Creek; this spot can be easily observed from the Lake Street Bridge in Lower Lake. The combination of elevation, gravel accumulation, and creek bed constriction physically limits the maximum amount of water that can pass through from the lakeside downstream to the rest of Cache Creek.
The Grigsby Riffle is what ultimately limits flow, even though the Cache Creek dam, operated by the Yolo County Flood Control and Watershed Conservation District, is currently open to allow maximum flow (currently at 2,750 cubic feet per second or CFS) to pass through the structure and down Cache Creek.
Sometimes the lake can fill up faster than the water can pass through the Grigsby Riffle, even if the dam is allowing maximum flow. That is why some years Clear Lake does reach a major flood stage and low lying homes get waves right up to their windows. There is nothing that can be done when this occurs.
There is a decree that prevents Yolo County from closing the dam when Clear Lake is at risk of flooding, but the nature of the physical outflow channel restricts flow sometimes during flood conditions.
Living on Clear Lake means you learn to live with the fluctuating conditions, there is not magic plug that can be pulled when the lake is too full and there is no magic spout to turn on when the lake is too low - it’s a natural lake and we all have to learn to love and appreciate that fact, during good times and even more so, during the difficult times.
If you don’t know about Yolo County’s Water rights over Clear Lake, and why they operate and control the lake level of Clear Lake, I suggest you visit my previous column from November 2021, “Wondering about Water Rights.”
I also recommend the information provided online by the County of Lake Water Resources including “The History of Clear Lake” and “How Yolo Obtained Water Rights.”
Indian Valley Reservoir
Yolo County also manages Indian Valley Reservoir, and while they are letting out maximum flow from Clear Lake through Cache Creek, they are keeping Indian Valley dam mostly closed so that reservoir can fill up to its maximum capacity.
Currently the water releases through Indian Valley dam are at a measly 11 CFS and the reservoir is only about half way full at about 175,000 acre feet. Yolo County is properly utilizing their reservoir storage while they are required to release water from Cache Creek to prevent flooding in Clear Lake.
If you want to know more about Yolo County water operations, or the water release amounts, you can visit their website here.
Flooding
Now that Clear Lake is more than full, we are hoping to only get rain in scattered, small bursts so we don’t reach a concerning flood stage on the lake. However, some low lying areas are seeing inundation, and may already be experiencing minor flooding.
As I stated above, If the lake reaches critical flood stage, there is nothing that can be done to magically make the water recede until it works its way out through the Grigsby Riffle and Cache Creek dam. Therefore, it’s up to the residents who live in low lying areas to be prepared in the event of a flood.
First, be aware of current conditions, bookmark the lake gauges on your browser, on your computers and mobile phones. Check them often as storm events occur and after, as stream flow continues to increase lake water levels even after precipitation has stopped.
Check your flood zone area on the county of Lake Flood Plain map page, but be aware that for some areas around Clear Lake, the flood zone distinctions have recently been updated, so calling the Water Resources Department, 707-263-2344 and asking the National Flood Insurance Program (NFIP) Coordinator about the most recent information is the best solution.
In the meantime, the best course of action to prevent loss or damage to property due to flood, is to be prepared. The county of Lake Office of Emergency Services released a series of “Flood Prep” best practice tips for being prepared against disaster during flood season.
Road closures, due to flooded conditions, can be located on Zone Haven along with information for when they are reopened and safe for travel.
Additionally, the Lake County Department of Public Works - California facebook page posted a list of locations to purchase sandbags and sand bag assembly materials. According to the Public Works Office administrator and facebook page manager, Lori Price, “Sandbag/sand locations updated as of 11:00 AM on 3/9/23. This post is pinned at the top of the page for easy access. We will try to update it as time allows.”
For more information about shelters, or emergency services, contact the Lake County Office of Emergency Services or call them at 707-263-3450.
Now is the time to help Lake County prepare and plan for natural disasters by being informed and involved in the Update to the Natural Hazard Mitigation Plan. Participation in this plan update is essential for appropriate emergency service planning and response. It’s also important for the County to acquire funds from FEMA for disaster mitigation, which can bring more resources to the County for disaster prevention.
Debris in Clear Lake
All this rain, storms, and water means that many tree branches, docks, yard furniture, and random other natural and man-made items, can now float away and become floating debris, or boating hazards, if they make it out to the open waters of the lake.
The seasonally-small team at Lake County Marine Patrol and the staff-strapped boat operators at Water Resources are working together to coordinate the towing of debris to public locations so they are not dangerous boating hazards. Once materials are towed to shore, Parks staff at Lake County and the two cities of Lakeport and Clearlake, can help to remove items and transport them to the lake county dump, or contact the owners for pickup. Some of this work is being supported by a Cannabis Tax grant.
If you see debris in the lake, or even beached detached buoys, you can report the locations to the Water Resources Department using this online “Boating Hazards Survey.” The survey takes about 1-2 minutes, and you can fill it out from your mobile phone if you are on the lake, notice the debris from shore, or later once you come off the water.
Debris does float, and crews are not on the lake 24/7 to respond to the survey, so please only report items that are landlocked, beached, grounded, or attached to something else so they don’t float away. A survey point for a floating object on the move is basically useless and those items can be called into Marine Patrol and a description and general location provided.
For property owners who live on the lake, it’s actually a requirement that docks or structures display or affix the owners address or contact information, as per County Code Chapter 23 section 6.5 (G) (H). Additionally, as part of lakebed lease agreements, it’s the owners responsibility to maintain and secure their lake structures so they don’t break loose or dislodge and float away, potentially destroying others’ property such as neighboring docks or passing boats.
Lastly, if you live on the lake, or visited the lakeshore recently, you might have noticed a bunch of dead tule stems crowding the shoreline. They look like large, round, hollow sticks. This material is rich in the nutrient nitrogen and once it decomposes along the shoreline, will help to provide nutrition for the new tules that are going to sprout up this spring.
If this material is a nuisance to you on your property, it’s okay to rake it up and dispose of it into a green waste container, or your compost bin. There is a plethora of nitrogen in the lake, and the new tule sprouts won’t be missing out, don’t worry.
However, if you don’t want to clean up the dead tule materials, they will be broken down soon by naturally-occurring bacteria and microbes, and wildlife, such as ducks and fish, will also use them for refugia and consume the algae that grows on them for snacks.
Let’s take some time to embrace and appreciate how wonderful it is that our lake is now, once again, full and vibrant. But let’s be mindful that another drought is only, perhaps, a year away.
Sincerely,
Lady of the Lake
Angela De Palma-Dow is a limnologist (limnology = study of fresh inland waters) who lives and works in Lake County. Born in Northern California, she has a Master of Science from Michigan State University. She is a Certified Lake Manager from the North American Lake Management Society, or NALMS, and she is the current president/chair of the California chapter of the Society for Freshwater Science. She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..
The Lady of the Lake would like to acknowledge and thank Wiliam Fox from the County of Lake Water Resources Department for contribution to this column.
