Fig. 4. Calculated denitrification uptake length (S_w,dn) and measured stream water concentrations of NO₃–N at sites BDO, LFK, and EMC, 1993–2002. (Site characteristics are given in Table 1.) The term S_w,dn was calculated using stream gaging records and an in-stream denitrification rate of 15 mg N m^–2 h^–1.