US Water Quality Index
Our composite Water Quality Score combines temperature, reservoir levels, and flow rates to rate conditions for swimming, fishing, and recreation.
How We Calculate Water Quality Score (0–100)
Maximum points when water temp is near ideal 71.5°F (22°C) for most recreational activities.
Full points when reservoir is at or near full pool capacity. Low levels reduce score.
Moderate, stable flow (100–5,000 cfs) earns full points. Extreme highs or lows reduce score.
Verdigris River Near Wagoner, Ok
Atoka Reservoir Near Stringtown, Ok
Red River Nr Courtney, Ok
North Canadian River Blw Lk Overholser Nr Okc, Ok
Delaware Cr Blw Del Cr Site 9 Rsvr Nr Bromide, Ok
Salt Fork Red River At Mangum, Ok
Willow Creek Near Albert, Ok
Horse Creek At 540 Rd Near Afton, Ok
Canadian River At Norman, Ok
Cimarron River Near Buffalo, Ok
North Fork Red River Near Tipton, Ok
Little Washita River East Of Ninnekah, Ok
Boggy Creek At 30Th St At Enid, Ok
Washita River Near Hammon, Ok
Elm Creek Near Commerce, Ok
Rock Creek At Sulphur, Ok
North Canadian River Blw Weavers Ck Nr Watonga, Ok
Lake Hefner Canal Near Oklahoma City, Ok
Lake Creek Near Eakly, Ok
Horse Creek At Afton, Ok
Understanding the Water Quality Index
The US Water Quality Index is a composite score designed to give anglers, swimmers, boaters, and outdoor enthusiasts a quick, at-a-glance assessment of water body conditions. Unlike traditional water quality indices that focus on chemical pollutants (which require laboratory analysis), our index uses real-time USGS sensor data to reflect physical conditions relevant to recreation.
Temperature Component (40 points)
Water temperature is the most important factor for recreational fishing, swimming, and wildlife activity. The ideal range for most activities — comfortable for swimming, optimal for bass and walleye fishing — is approximately 65–78°F (18–26°C). Our scoring peaks at 71.5°F and decreases proportionally as temperature moves away from this ideal.
Reservoir Level Component (30 points)
Reservoir levels (measured as a percentage of full pool) reflect drought conditions, drought recovery, flood risk, and overall ecosystem health. A reservoir at full pool (100%) scores maximum points. Severely depleted reservoirs — common during drought — score fewer points. This metric is particularly relevant in western states where water storage is critical.
Flow Rate Component (30 points)
River discharge (measured in cubic feet per second, cfs) indicates safe boating, wading, and kayaking conditions. Moderate, stable flow rates between 100–5,000 cfs are typically ideal for most recreation. Extremely high flows indicate flood risk, while extremely low flows suggest drought stress and limited habitat for fish.