Fig. 1.

(A) A side-shot diagram of the denitrification wall indicating the dimensions. (B) An image drawn to scale, delineating the denitrification wall location and the receiving seepage headwaters stream. (C) Large-scale map of the denitrification wall, including the contributing edge of field perimeter, elevation, and sampling stations where discharge, N concentration, and N load were measured within the treatment and control streams. Map created by author, using aerial imagery from Alachua County Property Appraisers (unpublished data, 2006).

 


Fig. 2.

A diagram of soil and water table elevation measured before the wall was installed and the approximate location of the wall.

 


Fig. 3.

The correlation between discharge and N concentration between the control and treatment stream. The correlation between discharge and nitrogen concentration between the two streams was strongly significant, justifying their comparison.

 


Fig. 4.

An analysis of the impact of the denitrification wall on N concentration and load. Shown in the figures are (A) N concentrations in the control and treatment stream before (Pre) and after (Post) wall installation, with significant change points indicated; (B) N load in the treatment stream pre and post wall installation; and (C) watershed rainfall, evapotranspiration (ET), and treatment stream discharge.

 


Fig. 5.

A paired watershed analysis of N concentration between the Control and Treatment stream. Shown in the figures are (A) N concentration correlations between the Control and Treatment stream before (Pre) and after (Post) wall installation, and N concentrations across the range of discharges measured for the (B) treatment and (C) control stream.