Student Research Projects

An analysis of the first flush effect and the impact of vegetation on stormwater drainage ponds.

Student Lee Brethower '15 (Biology)
Faculty Mentor(s)
Department Chemistry
Course Chemistry 489: Research in the Natural Sciences


In the current study the proposed hypothesis of the first flush effect (FF), as well as the impact vegetation has on the efficiency of stormwater drainage ponds (SWDP) was assessed. We propose that FF water samples will have higher nitrate (NO3-) and phosphate (PO43-) concentrations than non-FF samples and that SWDP with increased vegetation surrounding them will experience a greater reduction in NO3- and PO43- anions than those with little or no surrounding vegetation. To test these hypotheses, over a 5 month period we collected 350 water samples from 27 local SWDP which vary in vegetative abundance. We used ion chromatography to determine the concentration of NO3- and PO43- in each sample and subsequently examined the data using statistical analysis. Our data suggests that the SWDP we subjected to FF analysis show no significant anion concentration difference than the non-FF samples. Additionally, of the ponds we sampled, no statistically significant relationship was found to exist with varying vegetation abundance. Since only two of the SWDP had FF analysis conducted on them, future studies may benefit from a larger sample size for comparison of the first flush effect. Finally, using floating islands in microcosms or macrocosms may be a more suitable approach to determining the effect of vegetation on NO3- and PO43- concentrations since they are more easily controlled environments.