Technical Results
Construction Impacts on Water Quality
Construction | Post-construction
In general, during the construction period, concentrations of most
pollutants did not change in runoff from the traditional subdivision
(Figure 1). This occurrence is likely due to the effective use of
erosion and sediment controls. In contrast, concentrations of many
pollutants in the LID subdivision increased, likely due to the instability
of recently vegetated grass swales (Figure 1). However, on a mass
export basis, only TSS and TP export
increased from the LID subdivision (again due to problems with establishing
the grass swales). Export of all pollutants from the traditional
subdivision increased, due to the large increases in flow (Figure
2).
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| Figure 1. Significant changes in pollutant
concentration as a result of construction. Units are mg/L for
NO3-N, NH3-N, TKN, TP, BOD, and μg/L
for Cu, Pb and Zn. |
Figure 2. Significant changes
in mass export as a result of construction. Units are g/ha/wk,
except for Cu, Pb and Zn which are g/ha/mo. |
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