بررسي نقش مطالعات ژيومرفولوژي در تحليل هيدروگرافي حوضه هاي آبخيز (مطالعه موردي: حوضه آبخيز شوردره- استان گلستان)

Evaluation of the Role of Geomorphologic Studies in the Hydrographic Analysis of watersheds (A case study: shardarreh wathershed, Golestan Province)

The study of watershed geomorphology and analysis of its data as well as morphometery of the drainage network of watershed is of a great importance. In fact, geomorphology has a close relation with the condition of surface and ground water. More over assessment and classification of the earth side effects are often completely needed for the evaluation of environmental conditions and geomorphologic assessments are its fundamentals. In this article, we first studied the lithology physical features of the mentioned watershed as well as the applicable conditions of its land use and then through the study of quantitative geomorphology, waterways ranked with different methods as HORTON, STERALER, SHIDGER, SHERV. After ward, the watershed geomorphologic quantitative were computed and the results were derived. Finally the relations of rank - number of river branches, rank- area of watershed and rank- slope were identified. The results of this research indicate that we cannot the HORTON classification since this division is based on the length of waterways while it does not have a right scale for their comparisons. In the ranking system of SHIDGER and SHERV each external link requires an internal link. Thus, the size of watershed directly depends on the number of the first or second rate waterways. However, the results of geomorphologic studies show that the classification system of STERALER possesses a higher efficiency although the distances between different ranks are not definite in this system.