Is Old River Lake safe to swim?

As of July 20, 2026, Old River Lake in Pulaski County, Arkansas carries a swim caution. Satellite imagery measured 83,519 cells/mL of blue-green algae on July 19, 2026, elevated but below the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 2.7 in, which can wash bacteria and nutrients into the water.

How this read is built

Old River Lake is a lake in Pulaski County, Arkansas covering about 1.3 sq mi, the 32nd-largest of the 69 lakes SwimZone monitors in Arkansas. Satellite imagery measured 83,519 cells/mL of blue-green algae on July 19, 2026, elevated but below the 100,000 cells/mL advisory threshold.

Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.

Over 7 summers of satellite monitoring since 2020, Old River Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,892,270 cells/mL in June 2023.

Is it safe to swim in Old River Lake right now?

Old River Lake carries a swim caution today. Satellite imagery measured 83,519 cells/mL of blue-green algae on July 19, 2026, elevated but below the 100,000 cells/mL advisory threshold. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does Old River Lake have blue-green algae (cyanobacteria)?

Low levels. Satellite monitoring measured 83,519 cells/mL at Old River Lake on July 19, 2026, below the 100,000 cells/mL advisory threshold. Keep an eye out for surface scum, which can concentrate quickly.

Can dogs swim in Old River Lake?

Use caution. Blue-green algae at Old River Lake are elevated (83,519 cells/mL on July 19, 2026). Dogs are far more sensitive to cyanobacteria than people, so keep them out of the water and away from surface scum.

How often does Old River Lake have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Old River Lake has reached blue-green algae advisory levels in 7 of them, most recently in June 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,892,270 cells/mL in June 2023.

How many Arkansas lakes and beaches are unsafe for swimming today?

Today, 20 Arkansas waters are above a safe-contact threshold and 3 more warrant caution, out of 72 monitored waters SwimZone tracks in the state.

How is Old River Lake's water quality measured?

SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Old River Lake, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.