CASE STUDIES
Moses Lake
A comprehensive phosphorus management strategy reduced nutrient loading, improved water quality, and prevented risk advisories during peak recreation season.
THE CHALLENGE
Decades of Harmful Algal Blooms Impact Water Quality and Recreation
Moses Lake is a 6,800-acre freshwater lake in Washington that supports recreation, fisheries, and a regional economy valued at more than $300 million annually. The northern Rocky Ford Arm is particularly vulnerable to nutrient accumulation because it receives limited dilution from Columbia River water.
The lake has experienced harmful algal blooms since the 1960s. Despite wastewater diversion projects and ongoing dilution efforts, blooms continued to degrade water quality, introduce toxins, and negatively affect recreation, property values, and local economic activity. Excess phosphorus from watershed inputs and sediment release remained the primary driver of recurring bloom conditions.
The lake has experienced harmful algal blooms since the 1960s. Despite wastewater diversion projects and ongoing dilution efforts, blooms continued to degrade water quality, introduce toxins, and negatively affect recreation, property values, and local economic activity. Excess phosphorus from watershed inputs and sediment release remained the primary driver of recurring bloom conditions.
THE APPROACH
Reducing Both External and Internal Phosphorus Sources
A $3.1 million phosphorus mitigation project led by the Columbia Basin Conservation District was implemented in partnership with EutroPHIX and AquaTechnex. In 2024, EutroSORB® G was applied across 2,083 acres of the Rocky Ford Arm to reduce phosphorus release from lake sediments.
To address incoming nutrient loads, an automated EutroSORB® WC treatment system was installed in Rocky Ford Creek to reduce soluble reactive phosphorus before it entered the lake. This dual approach targeted both external nutrient loading and internal phosphorus cycling to improve water quality throughout the system.
To address incoming nutrient loads, an automated EutroSORB® WC treatment system was installed in Rocky Ford Creek to reduce soluble reactive phosphorus before it entered the lake. This dual approach targeted both external nutrient loading and internal phosphorus cycling to improve water quality throughout the system.
Reduced Phosphorus and Improved Recreational Conditions
The phosphorus management program delivered measurable improvements in water quality, reduced nutrient concentrations, and helped prevent risk advisories during the peak recreation season.
40
%
REDUCTION IN PHOSPHORUS AT ROCKY FORD CREEK
32
%
REDUCTION IN BOTTOM-WATER TOTAL PHOSPHORUS
0
HAB ADVISORIES DURING MEMORIAL DAY-LABOR DAY SEASON
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