Washington State Department of Ecology (Ecology) funding has helped many lake communities develop Lake Cyanobacteria Management Plans. Less often highlighted is the next phase: what happens after a plan is complete. In Camas, Washington, that implementation phase is now underway.

With the Lacamas, Round, and Fallen Leaf Lakes Cyanobacteria Management Plan in place, the City of Camas is focused on implementation, monitoring, and long-term bloom reduction. The plan provides a framework for managing harmful algal blooms in three waterbodies within the 67-square-mile Lacamas Watershed (Figure 1), where cyanobacteria blooms and recreational advisories have occurred repeatedly over the past decade.

What two seasons of implementation monitoring show

The City’s monitoring program is generating data across the three lakes and stream sites to inform management and track water quality trends. Annear Water Resources and Aquatic Insight are supporting the City by analyzing and interpreting these data to help evaluate lake conditions, treatment strategies, and future management priorities.

The dataset includes vertical profiles of temperature, dissolved oxygen, pH, specific conductivity, chlorophyll a, and phycocyanin fluorescence, along with nutrient chemistry and phytoplankton community composition.

The lakes follow a typical seasonal pattern for deeper eutrophic lakes. Thermal stratification develops in late spring and persists into early fall, with oxygen depletion at depth. During stratification, phosphorus accumulates in bottom waters as anoxic conditions promote release from sediments. This internal loading remains an important part of the lake nutrient cycle, although much of that phosphorus remains in deeper water while the lake is stratified.

In 2024-2025, microcystin was the only cyanotoxin to exceed Washington’s recreational guidance threshold of 8 µg/L. At Lacamas Lake public access areas, microcystin exceeded the threshold in 4 of 14 samples in 2025, compared with 13 of 20 samples in 2024 (Figure 2). Year-to-year comparisons should be made cautiously because conditions differ between years, but the lower number of exceedances in 2025 after moderate lake treatments is encouraging.

The phosphorus story points to importance of upstream sources

Soluble reactive phosphorus in the Lacamas Lake epilimnion remained at or near detection limits through much of the summer, while Lacamas Creek continued to carry detectable soluble reactive phosphorus during the growing season (Figure 3). Low soluble phosphorus near the surface does not mean low phosphorus supply. It simply indicates that bioavailable phosphorus entering the lake is being rapidly taken up by algae and cyanobacteria rather than accumulating in the surface water and points to the need to explore additional management options.

Lacamas Creek has long been identified as the dominant external phosphorus source to the lake system. However, the specific sources and spatial distribution of that loading within the watershed remain incompletely characterized. That gap increasingly defines the next phase of management.

Building the watershed picture

A new watershed phosphorus study also funded through the Ecology’s Freshwater Algae Control Grant program will help close that gap by evaluating external phosphorus sources and identifying priority areas for intervention. Ecology’s previous watershed source assessment work has already flagged elevated nutrient levels in several upstream tributaries, including China Ditch, Lower Fifth Plain Creek, and Dwyer Creek.

The Lacamas Watershed Council is also expanding tributary monitoring, adding spatial coverage and community-based data collection that will complement the City’s monitoring program. Together, these efforts will help connect upstream nutrient sources to lake conditions and support more targeted watershed actions.

Managing eutrophic lakes in a complex watershed is not a quick fix. Progress is necessarily incremental and data collection is an important part of this process. Two monitoring seasons into implementation, the City and its partners are building the baseline data needed to make each next step more targeted and defensible.

As the watershed picture improves, future progress to reduce phosphorus loading to the lakes will involve continued coordination and relationship building between the City, the Watershed Council, and Clark County to identify practical projects and funding opportunities to assist landowners on BMP implementation and restoration activities that contribute to the health of the watershed and lakes.