2026 Volume 21 Issue 2 Pages 119-126
Random deterioration of pumping wells is theoretically investigated by the use of a random differential equation describing temporally random variation of a health index of pumping wells, where actual data are obtained from 24 wells in Joyo city and Yawata city located in Yamashiro area of Kyoto prefecture, Japan. First, based upon actual data obtained from 24 wells in Joyo city and Yawata city located in Yamashiro area of Kyoto prefecture, Japan, the mean behavior of deterioration can be well approximated by an exponential deterioration. Next, a random differential equation is constructed by introducing a Gaussian white noise into the mean behavior, which leads to that the health index of wells obeys a log-normal distribution. Finally, it is demonstrated that the proposed model accurately reproduces the temporal variation in the observed health index variability in both areas. Furthermore, it is revealed that the average deterioration progresses more rapidly in the Yawata area than in the Joyo area, and this trend is discussed in relation to geological characteristics.
