Showing 2 results for A. Esmaili
A. Ghane, M. R. Ahmadi, A. Esmaili, A. Mirzajani,
Volume 10, Issue 1 (spring 2006)
Abstract
Present study investigates macrobenthic invertebrates and their community structure in Chafrood river to classify and assess the study sites regarding the environmental anthropogenic factors. Along a 9 km distance, 8 study sites were selected, and macrobenthic were monthly sampled using a surber sampler (1600cm2, 250 μ mesh net) with 3 replicate at each station. Collected samples organisms were fixed with 4% formalin and laboratory process including sorting, identification and enumeration of the animals were preceded. During the study 73 benthic taxa were identified which were dominated with aquatic insects larvae especially orders Diptera and Ephemeroptera. The maximum and minimum total abundance was 2335 ind.m-2 in station #2 and 1639 ind.m-2 in station #4 respectively. Benthic animals' frequency data were summarized to community structure metrics including total richness, EPT richness and ratio of EPT frequency to Chironomidae family. A Shannon- Winner diversity index and Hilsenhoff family level biotic index was also determined for each studied station. Result of cluster analysis for stations, based on the community structure metrics and diversity index, was in accordance with the station classification using biotic index and both classify the affected stations at the same group.
A. Esmaili Nameghi, A. Hassanli,
Volume 11, Issue 1 (spring 2007)
Abstract
One of the simple methods for erosion control, flood mitigation and flood damage reduction in the streams is building the checkdams. The present study was carried out to evaluate the performance of checkdams, location across the streams in the retention of the fine sediments in Droudzan watershed in Southern Iran. For this purpose, a number of streams with many stabilized check dams which were more than 27 years old were selected. For each stream, three check dams (one at the far beginning (upstream), the second one at the middle and the third one at the far downstream) were selected. In each stream, a number of samples were taken from retained sediment behind the selected check dams and also original soil was taken from both sides of the same check dams. Laboratory analysis on the size of particles and also texture of soil and sediment samples showed that in general, soils taken from both sides of the check dams were finer than sediment behind the same check dams. Comparison of particle sizes showed in all streams except Joobkhaleh (with extensive tree coverage) the performance of the third check dams (far downstream) in fine sediment retention is much better than the second one (at the middle) and the second one is more effective than the first one (upstream). Comparison of sands, silt, and clay percentage of soil and sediment also showed that in all streams except Joobkhaleh the clay and silt percentage behind the third check dam is more than the second check dam and that of the second check dam is more than the third one (upstream). In the same way, results showed that the sand retained behind the first check dam, was more than the sand behind the second and first checkdams, respectively. Therefore, if the retention of the fine sediments is the main purpose of the check dam construction, it is recommended that they be built in the far downstream rather than in the upstream of waterways.
