Springer Iranian Journal of Science 2731-8095 29 3 2005 12 28 EFFECT OF MONITORING TIME INTERVAL ON THE RESULTS OF STOCHASTIC ANALYSIS OF KARST WATER RESOURCES 387 399 2815 10.22099/ijsts.2005.2815 EN M. ZARE Department of Geology, Shiraz University, I. R. of Iran 2Department of Statistics, Shiraz University, I. R. of Iran A. R. NEMATOLLAHI Department of Statistics, Shiraz University, I. R. of Iran M. RAHNEMAEI Department of Irrigation, Shiraz Islamic Azad University, I. R. of Iran Journal Article 2005 04 19 Data monitoring is important in the study and analysis of hydrological behaviors of karstic<br />systems. Monitoring shows the various regimes of groundwater flow (laminar or turbulent), depletion,<br />filling, filtration and karstification degree of karst aquifers. In recent years, analyses of these data had<br />considerable advances using stochastic time series analyses. An important problem related to these<br />analyses is the constraint of financial and technical human support. If we can increase the time intervals,<br />the costs are lowered and development of new monitoring networks will be possible. In this research, the<br />effect of monitoring time intervals on the results of time series analysis and calculated hydrologic delay<br />times are studied, using bivariate analyses in spectral domain. The first (shorter) and the second (longer)<br />delay times are related to the flow of groundwater through the larger and smaller fractures of the karstic<br />system, respectively. Daily groundwater level data of three piezometers and the discharge of a spring in<br />the Maharlu karst basin in Iran (52􀁄12′ to 53􀁄28′E and 29􀁄1′ to 30􀁄6′N ) were acquired and then six<br />different time series having different time intervals (1, 3, 7, 10, 14 and 30 days) were extracted and<br />analyzed. The results show that the variation of the computed stochastic parameters with increasing time<br />intervals is unpredictable, but the variation of time (period) corresponding to the frequency at the peak of<br />amplitude function (curve) shows a linear and predictable relationship, which is unique for every kind of<br />karstic aquifer having different degrees of karstification. https://ijsts.shirazu.ac.ir/article_2815_e4d792d269fba9a9da978a1f80d5196a.pdf