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.
Turkey Creek At Morris Al
Little Cahaba River Nr Jefferson Park, Al.
Elliotts Creek At Moundville Al
Big Creek Near Seven Hills Al
Cahaba Valley Cr At Indian Trail Rd Nr Indian Sprs
Blackwater River Near Bradley Al
Flint Creek At Red Bank Rd Se Nr Decatur, Al
Fish River Near Silver Hill Al
Bodka Creek Near Geiger, Al.
Big Swamp Creek Sw Of Hayneville, Al
Blackburn Fork Little Warrior R Nr Holly Springs
Hamilton Creek At Snow Road Near Semmes, Al.
Big Wills Creek Near Reece City
Bassett Creek At Us Highway 43 Nr Thomasville, Al.
Crooked Creek Near Fairview, Al.
Flint Creek Near Falkville Al
Magnolia River At Us 98 Near Foley, Alabama
Little River Near Blue Pond Al
Hester Creek At Buddy Williamson Rd Nr Plevna, Al
Shades Creek At Elder St Near Springdale Al
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.