Land Use and Flow Regimes Effect on Phosphorus

TheWinooski River is one of the largesttributaries to Lake Champlain and thus plays a major role in Lake Champlain’sWater quality. In this study, Land use and flow regime effects on phosphoruschemical dynamics in the fluvial sediment of the Winooski River, Vermont, the objective was to determine if land useand flow regime influenced whether Winooski River sediments acted as a sink orsource of phosphorus entering into Lake Champlain. Phosphorus is the leadingcause to algal blooms, an increasing problem in Lake Champlain, and is animportant element to study and track to see how changes in a river can changephosphorus levels.

To better understand the transport, storage, and cycling ofphosphorus within the Winooski River, this study examined the chemistry,bioavailability and processes controlling sediment phosphorus release to watersof the Winooski River.

To see if flow regimes and land use had an affect on phosphorusrelease this experiment paid particular attention to the role of artificiallyconstructed flow regimes in engineered impoundments in comparison to thenatural flow regimes of river and reservoir sites. Also, the influence ofdifferent land use adjacent to the river was highlighted, since intensive landuse is known to increase phosphorus loads.

The results of the experiment showed that phosphorusconcentration was significantly greater in impoundment sediments than in eitherreservoir or river sediments. Demonstrating that there is a strong influence offlow regimes and water hydraulics that affected the chemical properties of thesediment in the Winooski River. Also, sediments adjacent to agricultural landhad a significantly greater concentration of phosphorus than sediments adjacentto forested land. Therefore, the input and delivery of finesediment enriched with phosphorus was also influenced by adjacent land use. Itis clear from this experiment that both flow regimes and land use play a majorrole in soils ability to retain or release phosphorus and the overall health,of not only the Winooski River, but Lake Champlain as well.

Land use and flow regime effects on phosphorus chemical dynamics in the fluvial sediment of the Winooski River, Vermont