Exploring Freshwater Streams: Cherry Creek and Bear Creek

Trisha McNiff BIOL 2081­005 Tucker 04/23/2013

Introduction

On April 6th 2013, our Biology II lab evaluated the health of two freshwater streams in the Denver area. Both creeks flow to the South Platte River but are situated in different environments (urban and suburban) which cause variance in biotic and abiotic indicators of stream health. The presence or absence of bioindicators is dependent on the water chemistry. Through the study of stream health, we can gain insight on the stress that humans cause to freshwater habitats. I think that Bear Creek is healthier than Cherry Creek because it is in a less urban environment and is less affected by human influences. If the
The area studied at Bear Creek was a short walk from 2900 S. Estes Street in Lakewood. We walked over a bridge and down the stream about 100 yards and found an area fit for study. Using measuring tape, an area ranging 10­meters that included both the pool and riffle was measured. This was the stretch of

the creek from which data was collected. Next, pre­labeled nalgenes were used to collect water samples from the pool, riffles, and mid­stream. Then, the samples were tested. We measured and recorded the temperature of each water sample using a thermometer. Ph was obtained from each sample using a Melter Toledo 7 Go Pro pH meter and a CHEMetrics chemistry kit as directions indicated. Salinity and total dissolved solids were found using a meter. Any trash left from this experiment was disposed of in a container labeled “trash” and any broken ampules were placed in a container labeled “sharps”. We measured a transect running across the bank at the top of the 10­meter length that has been designated for study. We then placed another transect from one bank to the other 5­meters downstream (half way), and placed one more at the end of the 10­meter length. Using measuring tape,the width of each transect was measured. The depth at each bank was measured using a meter stick. The substrate on each transect was described and recorded. Using a flow meter, we estimated the rate of water flow in the middle of the creek.