Over the last few decades, Strawberry Creek has experienced various urban disturbance events. These events have included sewage spills, chemical and thermal pollution, as well as influxes of chloramines and heavy silt from water main breaks. Recently, Strawberry Creek experienced one such event, but on an exceptionally major scale. On June 12, 2005, Strawberry Creek was again inundated with discharge flows from a water main break near the Lawrence Berkeley National Laboratory. Following the break, between 200,000 and 400,000 gallons of chloramine-treated water passed through the creek. The flow continued for a number of hours, and resulted in chloramine contamination, deposition of fine silt, and displacement of newly hatched fish fry. The entire reach of the North fork of Strawberry Creek, as well as portions of the Main Branch below the confluence, served as a conduit for the discharge from the water main break.
UC Berkeley Aquatic Ecology students have been monitoring Strawberry Creek using US EPA’s Rapid Bioassessment Protocol for approximately the last decade. The most recent study began in March of 2004 and continued through July 2005, encompassing the period of the June 2005 water main break. Data from this study have been used to monitor benthic macroinvertebrate community response to flows from this spill event. The two primary objectives of this monitoring are: to determine whether or not the water main discharge affects benthic macroinvertebrate communities in Strawberry Creek; and, if these communities are affected by water main discharge, to determine community-level biological responses. The South Fork did not receive any of the discharge from the water main break, and is therefore considered a control site for the purposes of this analysis. As such, we present the following null hypothesis: there is no difference between the benthic macroinvertebrate communities on the North Fork of Strawberry Creek, and the benthic macroinvertebrate communities on the South Fork of Strawberry Creek. Therefore any differences observed between the North Fork and the South Fork can at least potentially, be attributed to ramifications of the water main break.
