WATER QUALITY IN RIPARIAN BUFFER ZONES OF TWO URBAN STREAMS

Riparian buffer zones are thought to influence the quality of water entering the streams through various biogeochemical processes. Resources are used to reconstruct damaged riparian areas, but the effectiveness of these projects is poorly understood. This project focuses on quantifying the impact of riparian buffer zones on the water quality of the streams. Buffer zones are characterized by the types of vegetation present in the riparian zone, the size of the buffer, and connectivity of the riparian zone to the stream. Two urban streams in Philadelphia were examined for this project: a 500 m section of the Tookany Creek, and a 1500 m long tributary, Mill Run. The urban streams examined for this project have varying types of riparian zones, and degrees of connectivity of the streams to the riparian zones. The streams each have sections of channelization and incision that disconnect the stream from the buffer and increase discharge. The stream health was characterized by several factors as indicators of stream health. Temperature and light were monitored along the streams through the use of data loggers. Algal growth was mapped near the loggers. The final aspect of this project was the collection and analysis of water samples from various points along the stream. These points included stormwater outlets, pressure release points in the channelized sections, tributaries, and sections of the main streams. The water samples were analyzed for nutrients. The stream water quality is thought to be aided by the riparian buffer zone; however, there was little to no difference in nutrients measured as the riparian buffers change. There were also no discernible patterns in the temperature response to storms or algal cover as the riparian zones changed. Through this examination we hope understand whether the positive impact of riparian zones are lost in channelized and incised streams strongly impacted by storm discharge.