About Pattison Lake

Follow the water flow

Pattison Lake is a spring-fed and rain-fed lake. Pattison Lake is part of a four-lake Woodland Creek drainage system. Hicks Lake flows into Pattison Lake, then Long Lake, and into Lois Lake, which drains into Woodland Creek, and finally to Henderson Inlet in Puget Sound. The water quality of the lakes is rated “good to fair” with issues that include an increase in algae blooms and aquatic plant growth. The water quality of Woodland Creek is rated as only “fair” due to issues with fecal coliform bacteria and it is on the Washington State Department of Ecology’s list of impaired waters.

In July 2024, the Pattison Lake Management District has contracted with Herrera, Inc., to study the lake water quality, plants and core sediment. The Integrated Aquatic Vegetation Management Plan will be completed in spring 2025. Based on preliminary results, the aquatic plant community in Pattison Lake is composed almost exclusively of native plants, with the exception of fragrant waterlily and curly-leaf pondweed. The PLMD identified native species, common waterweed (Elodea canadensis) and Richardson’s pondweed as nuisance aquatic plants. Visit the website for details. See the report.

Noxious emergent plants (plants that grow along the shoreline and above the surface of the water) are present on Pattison Lake. Noxious emergent species present along the shoreline include reed canarygrass, yellow-flag iris, Himalayan blackberry, spotted jewel plant, birdsfoot trefoil, bittersweet nightshade, and St. John’s wort.

Lake science: Lakes age

Freshwater lakes are created, they age and they die, in a predictable pattern; the process of aging is called succession. It is common for urban lakes to have too many nutrients fed by humans and other systems, so the lakes age much more quickly than lakes in the wilderness.

The deterioration of water quality in Pattison Lake is caused by nutrient pollution, which includes excessive use of fertilizers and nitrogen, warmer water temperatures, stormwater run-off, poor erosion control, malfunctioning septic systems, improper waste disposal, and contaminated groundwater. Also, hard surfaces contribute to the volume of water moving through the lakes and wetlands. The run-off erodes soils and transports more organic materials. Soon, nutrients accumulate, which causes excessive weed and algae growth.

An oligotrophic lake has low nutrient concentrations and low plant growth. It usually has sand or rock along most of the shoreline, and there is a high dissolved oxygen content. For example, Lake Tahoe in Nevada, is a stunning blue, clear lake because it has very few nutrients in it.

A mesotrophic lake has some aquatic vegetation and can support warm water fish species. There is moderate nutrient enrichment and moderate planktonic growth. These are commonly clear lakes with submerged aquatic plants and medium levels of nutrients.

A eutrophic lake, such as Pattison Lake, is well nourished with high nutrients and high plant growth. It occurs when oxygen, nitrates and phosphates, plus more nutrients are washed into the lake, to allow plants, such as algae, to grow and reproduce. Human activities contribute to excess amounts of nitrogen and phosphorus into the water. The sediment can be high in phosphorus. The more algae that grows, the cloudier, murkier and greener the water gets. It has warm water fish species. The water body loses much of its dissolved oxygen so normal aquatic life begins to die.

Pattison Lake water quality summary

Thurston County routinely monitored water quality in Pattison Lake during the summer season (May through October) every year since 1996 in the south basin and all years except 2009 through 2021 in the north basin (Thurston County 2024b). Data from 2022 and 2023 show that both basins thermally stratified during the entire monitoring period with the exception that the south basin mixes by October. This stratification of the warm surface (epilimnion) over the cool bottom layer (hypolimnion) has has resulted in very low dissolved oxygen concentrations (less than 2 milligrams per liter [mg/L]) at the bottom of both basins. The low dissolved oxygen concentrations impair fish habitat and cause the release of phosphorus from lake sediments, which fuels algae growth in lake.

Routine water quality monitoring includes measurement of the three trophic state parameters: chlorophyll-a, which is a measure of algae biomass; total phosphorus, which is the most limiting nutrient for algae growth; and Secchi depth, which is a measure of water clarity affected by the amount of algae. Pattison Lake is classified as eutrophic (high algae and nutrients) abased on high average concentrations of chlorophyll-a, which have fluctuated somewhat but not increased since 1996 (see graphs, courtesy of Thurston County Environmental Health).

Learn the lake zones

Littoral zone where sunshine penetrates to the sediments and allows aquatic plants (macrophytes) to grow.

Euphotic zone: In the deeper water where light levels become too low for. photosynthesizers. For most lakes, the sunlit euphoric zone occurs within the epilimnion.
Benthic zone: Beneath the water.
See graphic below for illustration. Courtesy of Lake Access, Three Rivers Park District Duluth, Minnesota.

Phosphorus and nitrogen increasing in Pattison Lake

The lake water quality standard is 0.025.mg/l of phosphorus, which was the level of our lake in 2015, but in 2017 it was 0.200, or 8 times higher than it was and should be.

The nitrogen level in 2015 was .600 mg/l, but in 2017 it was 1.400, or more than twice the prior level.

Higher phosphorus and nitrogen degrade water quality

Both phosphorus and nitrogen are dramatically higher than they were just a few years ago and indicate that our lake water quality has deteriorated. Higher phosphorus levels lead to an overabundance of aquatic plants, which rob the water of oxygen needed by fish. Higher phosphorus and nitrogen levels both increase the frequency and severity of algae blooms, decreasing oxygen levels, leading to fish kills and unsafe conditions for other animals and humans.

See reports from 2021.

Plant monitoring data and resources

Noxious weeds consistently found in Pattison Lake measured by the county.

Yellow Flag Iris

· Toxicity: Sickens livestock and avoided by herbivores. Resins in plant can cause skin irritation in humans

· Presence: Perennial, aquatic 2 to 3 feet tall plant grows in shallow water spread by rhizomes & seeds

o Mechanical: pulling or digging irises, protecting skin from resins in leaves and rhizomes. All rhizomes fragments must be removed. Seeds germinate and rhizomes regrow after being burned in late summer.

o Herbicide: Cut stems off, dispose so stems will not regrow, and apply herbicide to the stump

Invasive Species Nuisance Plants reported by lakefront owners affecting recreation

· Naiad: a feathery water plant – homeowners report a Rapid Increased in growth of naiad.

· Water Lilies: spreading each year over more acres from the north and south sides of the railroad

Washington State Technical Assistance available to control Aquatic Invasive Plants

Permits: Ecology offer permit coverage for a range of activities, from noxious and invasive weed control, to mosquito control, and fisheries resource management. There are currently the following general permits that control the use of aquatic pesticides:

Aquatic Invasive Species Management Permit — sets conditions on the use of products for managing aquatic invasive species, including animals and non-native, invasive marine algae.

Aquatic Noxious Weed Control Permit — sets conditions on the control of state-listed noxious and quarantine weeds along freshwater shorelines, wetlands, or estuaries.

Aquatic Plant and Algae Management Permit — sets conditions on the management of plants and algae, and the use of nutrient-inactivation products in fresh water bodies.

Question / Answer with Thurston County Environmental Health in June 2023

When does Thurston County Environmental Health start algae testing? When do you end algae testing for the year?
Thurston County Environmental Health (TCEH) respond to cyanobacteria (also known as blue-green algae) calls year round and will take samples of cyanobacteria if scum is present. All cyanobacteria response and testing is response-based and there is no passive cyanobacteria monitoring at this time. All suspect cyanobacteria scum samples collected are sent to King County. The typical algae season is April through November. If a cyanobacteria bloom is suspected outside of this season, we need the reporter to also send pictures of the bloom along with their complaint form to be submitted from the lab for permission to submit a sample of the scum.
2. How do you report algae (link/website/etc.)?
Fill out an issue report form at this link.
After you report it to Thurston County, send an email to the Pattison Lake Management District with this information:
Date
Time
Location (address)
Who reported it?
Phone number
Why? Because The Pattison LMD is tracking this information and data. Thurston County does not release the name of the reporter nor the address, so the LMD is tracking data as well.
3. How do lake residents sign up to receive algae testing results?
- Current advisories can be found here
- Our lake sampling season is conducted from May through October. They sample 10 lakes throughout Thurston County, and cover 14 sampling sites across these lakes. This, along with stream sampling, is an ongoing project to monitor local water quality.
- They sample at the deepest location in the South and North basins in Pattison Lake, collecting profile data on water quality parameters including temperature, dissolved oxygen, pH and conductivity. They also collect samples at the surface and bottom for phosphorus and nitrogen, and a composite sample to look at chlorophyll and phaeophytin.
  3. Where does the algae come from?
- Cyanobacteria, also known as blue-green algae, are bacteria which have some of the characteristics of plants. Cyanobacteria are found throughout the world on land and in lakes, rivers, and ponds, and in estuaries and seawater (oceans). Cyanobacteria (or blue-green algae) can produce toxins at levels that are harmful to humans, pets, domestic animals, and wildlife. There is no way to detect toxins in an algae bloom except through laboratory analysis. Not all cyanobacteria blooms are toxic. Even blooms caused by known toxin-producing species may not produce toxins or may produce toxins at undetectable levels. Scientists do not know what triggers toxin production by cyanobacteria. Toxicity is hard to predict in part because a single species of algae can have toxic and non-toxic strains. Also a bloom that tests non-toxic one day can turn toxic the next day. Also note that there are green algae in lakes and they create blooms as well, but these blooms do not produce toxin.
How are WARNINGS posted, where, by who, how long do they stay up, is it safe to get in the water even if posted, etc.?
- WARNING signs are posted in response to a sample result above the Washington State Advisory Level for cyanobacteria.
- Advisories stay in place until two weeks of consecutive sample results are below advisory levels. Signs would be taken down when the advisory ends.
- Thurston County Environmental Health or volunteers post signs at public access points (i.e., Public boat launches and community lake access points) and sends out an email alert to lake community members.
- With volunteer help, the county plans to post signs at community access points to minimize interaction with the water when public health is at risk. They will send an email to volunteers when results indicate the need for signage, and then when the signs should be taken down. For best public response, the county will need to make sure signs only stay up with needed, or people tend to not pay attention to it.
  How can lakeside property owners help reduce algae?
- Reducing nutrients (especially phosphorous) is key.
  - Maintain septic systems (check annually, pump every three to five years)
  - Minimize fertilizer use
  - Manage pet waste – dogs in particular
  - Cover any manure piles
  - Do not feed / encourage wildlife
  - Geese – mainly something to work with USDA wildlife service program regarding, but they can be discouraged by planting a 6-8 ft hedge (low shrubs to not block lake view)
How can Environmental Health best help you?
- Active involvement with the community, including outreach and education to continue practices that limit nutrient loading.
- Alerts to when algae is present – seeing as the program is a response based vs. active monitoring.

To find information about the Pattison Lake Management District

Pattison Lake property owners and those within the Pattison LMD boundary voted to form the Pattison Lake Management District. See website for details about Pattison Lake Management District.