COMPARING THE WATER QUALITY OF STREAMS FEEDING A WATERSHED

Abstract

The Ala Wai Canal is one of the main waterways and watersheds on the island of Oʻahu, but it does not meet EPA water quality standards. Despite being deemed unsafe, during paddling season a number of adult and teenage paddling crews practice in the Ala Wai for a variety of reasons. In recent years, more discussion and focus has been turned to improving the water quality of the Ala Wai Canal. By doing a water quality study on two tributaries that feed into the Ala Wai watershed, the research group hoped to determine if there was a statistically significant difference between the mean water quality of the two streams. By measuring 952 samples in Pūkele Stream and 889 samples in Makiki Stream taken every fortnight over a 14-year period, the representative suspended solids entering from the eastern and western sides of Ala Wai Canal are compared statistically. Thus, a good general picture of the average difference in water quality between the tributaries is obtained. Through this sample study, it was found that there is a statistically significant difference between the average water quality of the two streams. This finding implies that there is a big enough difference between the suspended solids in the two streams to prioritize the Pūkele Stream over Makiki Stream for remedial actions.