Data analysis for hydrologic atlas of Iran


Category:  Watershed Science
Linked Publication
Language: English
Author(s): Ali Babakhani
Description: Data collected in the fields of climatology, soil science, geology, and plant distribution are put together to outline a general draft of the existing hydrologic conditions and water supply situation in Iran. These data may serve as to identify and initiate more investigations in water and soil related fields in hope of more improvements achievable in the future. Three sets of data from stream gaging stations (45 stations with 45 historical flood values, 20 stations with 251 station-years of record, and 14 stations with 178 station-years of record) were selected in the Caspian Sea water division. These data sets were analyzed by hydrologic techniques such as: Maximum probable flood curve, flood frequency analysis using log normal, Cumble, and Pearson Type III distributions, and regional frequency analysis. The results or the above analysis gives an estimate of the magnitude of the peak floods even from ungaged watersheds located in the Caspian Sea area. Because this analysis is the first of its kind performed on data from this region of Iran, there are no criteria available for comparison. It was found that, within the limited range of available data, different distributions fit some stations better than other stations. In general, a log normal distribution fits best, a Pearson Type III fits next best and the Gumble gives the poorest fit. The short length of record and numerous estimation of missing data by regression techniques has reduced the quality of the data used. However, the outputs are reasonably within the range of acceptance.