Abstract
The self-purification of the creeks is very important for water quality to purify. Among past research, point out the usable Aquatic Organisms environment Diagnostics (abbreviated as AOD) estimate the flow rate that the creeks need, achieves the purpose that water quality purifies with the mechanism which dilutes function . In addition, plant is very important in water-purification. Show in past research, all there is very great help in conversion with the nitrogen element and nutrition salt in the creeks. In this study, we investigate the affection of plants on the water self-purification by using AOD. This study is mainly to use AOD as the measuring tool of water quality of quantization. We measure the water quality of the Dou-zih-pu creek in Jhubei. Calculate the plant can offer the purification efficiency of unit's proportion and unit's area. In order to offer the reference of small stream management project of the Dou-zih-pu creek in the future. We get the changing amount presents positive correlation with AOD value to the proportion or area of plant, and it is a Napierian logarithm curve. Take an example, if we want let the water quality in Jhubei senior high school for Macrobrachium asperulum to live. We must improve AOD value by 541%, but after calculating even the proportion of plant is 100% can only reply 269%. We must use other ways to lower the content that water pollutes. And Macrobrachium asperulum overcome the water quality to survive. In order to irrigate farmland conveniently or drain water smoothly, we must clear plants in watercourse. This study provides a better model for leaving some proportion of plants for water self-purification. The equations in this study make a balance between water-purification and water-conservation.