농촌 소하천에서의 재폭기 계수 추정

Prediction of Reaeration Coefficients in Rural Small Streams
한국농공학회지 v.43 no.5 , 2001년, pp.163 - 171  

송인홍 ( Song In Hong ) , 권순국 ( Kwun Soon Kuk )

Abstract

Reaeration phenomena, the physical process of absorption of oxygen from atmosphere, is one of the important parameters of dissolved oxygen simulation in streams. This study was aimed at predicting reaeration coefficients in rural small streams, examining the influence of drop structure on reaeration and the seasonal fluctuation of reaeration coefficients. Reaeration coefficients of five strams including four tributaries of Bokha watershed in Gyeonggi Ichon and Onyang stream in Chungnam Onyang were measured. Constant rte injection (CRI) method using propane and Rhodamine-WT as gas and dye tracer was adopted. Reaeration Coefficients ranged between 6.16 and 29.16 reciprocal day, higher than those in USGS database. Prediction equation. K₂ = CV^0.593, was regressed from the measured data at 95% confidence level, with an absolute error of 21.2% and a standard error of 4.0 reciprocal days. Reaeration coefficients of experimental reaches with drop structure showed percentile increases of 42.3 to 159.2 compared to those without it, an indication that drop structure plays and important role on stream reaeration. Taking into consideration the seasonal fluctuation of reaeration coefficients, the values measured during September and October were the highest. Mainly due to the removal of aquatic plants, by intensive rainfall during summer.