title: Monitoring nitrogen loading and retention in an urban stormwater detention pond.
abstract: Stormwater detention ponds have become ubiquitous in urbanized areas and have been suggested as potential hotspots of N transformation within urban watersheds. As a result, there is a great deal of interest in their use as structural best management practices to reduce the excessive N export from these watersheds. We conducted continuous monitoring of the influent and effluent N loads of a stormwater detention pond located on the Princeton University campus in Princeton, New Jersey. Our monitoring was conducted during four 21-d periods representing the four seasons of the northeastern United States. Water quality samples were collected and analyzed for nitrate (NO3-) during all four monitoring periods. During two of these periods, loads of ammonium (NH4+), dissolved organic N, and particulate N (PN) were measured. Our results show that NO3- dominated the influent N load, particularly in dry weather inflows to the detention pond. However, PN, which is often neglected in stormwater quality monitoring, made up as much as 30% of the total load and an even greater fraction during storm events. The results of our monitoring suggest that seasonal variation may play an important role in N retention within the detention pond. Although retention of NO3-, the most dominant fraction of N in the influent stormwater, was observed during the summer sampling period, no significant NO3- retention was observed during the spring or the two cold-weather sampling periods.
authors.affiliation: Civil and Environmental Engineering Dep., Engineering Quad, Princeton Univ., Princeton, NJ 08544, USA.
authors.forename: Bernice R
authors.initials: BR
authors.lastname: Rosenzweig
authors.forename: James A
authors.initials: JA
authors.lastname: Smith
authors.forename: Mary Lynn
authors.initials: ML
authors.lastname: Baeck
authors.forename: Peter R
authors.initials: PR
authors.lastname: Jaffé
mesh_terms: D002947:Cities; D004784:Environmental Monitoring / Q000379:methods; D009515:New Jersey; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism*; D012621:Seasons; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014881:Water Supply
chemical_list: D014874:Water Pollutants, Chemical; D009584:Nitrogen