Expanding the Limits of Small Stream Biocriteria NC DWQ Larry Eaton Cheryl Gregory

NC Small Stream Biocriteria Developed May 2009 by Eric Fleek 69 page document Land use is Gold Standard Qual 4 sampling method Biotic Index only metric Index period April, May, June

Small Stream Biocriteria (Biotic Index) Bioclassification Piedmont Mountains Excellent <=4.36 <=3.75 Good 4.37-5.48 3.76-4.99 Good-Fair 5.49-6.02 5.00-5.80 Fair 6.03-6.98 5.81-6.70 Poor >=6.99 >=6.71

Limitations for Use in Restoration Success Lower limit poorly defined – restorations down to 0.3 mi2, validation only 2 sites below 0.5 mi2 Small Index Period – would be more useful at 6-9 months

Study Design (ongoing) 6 Watersheds in Mountains 6 Watersheds in Piedmont Each watershed sampled 3x/yr 4 size classes in each watershed <0.1 mi2 (64 ac) 0.1-0.75 mi2 0.75-3 mi2 >3 mi2 144 Samples Total

Biotic Index for Mountain Sites

Biotic Index for Piedmont

When Method Doesn’t Work When water is so shallow it will not flow into kick net When site dries up in summer

1/4” Deep Stream

Dry Triassic Stream

Ref EPT Taxa Richness (Mtn Streams)

Seasonality

Summary In mountains (where most streams spring fed and perennial), method seems to work. In Piedmont, method limited to streams deep enough to do a kick sample that don’t dry out in summer There may be a way to incorporate EPT taxa richness into method on a sliding scale of stream size Data is being collected to see if it is possible to expand index period (maybe with seasonal correction)

Questions?