IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2004 | Volume:57 | Issue:3|Papers Count:17

The study of relations between morphologic characteristics of basins and their hydrologic response is one of the important issues in the science of hydrology. Geomorphologic instantaneous unit hydrograph (G.I.U.H) and Geomorphoclimatic instantaneous unit hydrograph (Gc.I.U.H) and GRAY unit hydrograph are some results of the efforts in this field in order to evaluate the efficiency of these models in determination of the shape and ordinates of direct runoff hydrograph, Navrood representative basin in southwest ledge of Caspian Sea in west of Gillan Province was considered. Database of 6 events of rainfall-runoff in non-melting seasons was collected. Ordinate of unit hydrograph and direct runoff hydrograph were calculated by using the above models for selected events, separately. The results show that G.I.U.H and Gc.I.U.H models in comparison with GRAY model are better fit for use in determination of peak discharge in direct runoff hydrograph but there is no significant difference among them in determination of time to peak, base time and volume of direct runoff. In addition, Gc.I.U.H model in comparison with G.I.U.H is of a higher efficiency for determination of the ordinates of direct- runoff hydrograph especially in cases with less peak discharge.

Soil erosion, transportation of eroded material and sedimentation cause many problems in the hydrologic cycle of watersheds. Study of different stages of erosion and the recognition of control methods is very important in planning and managerial activities. Extended studies have been conducted in qualitative and quantitative evaluation of soil erosion, transportation and sedimentation. Dynamic models known as time variant or memory models are those related to time and therefore, time parameter plays an important role in system output. Dynamic models can be developed using daily precipitation, water and sediment discharge collected during a specific period.In the present study, the Kasillian watershed with an area of 6878ha located in forest region of northern Iran, having considerable precipitation, discharge and sediment data, was selected. Initially, the available precipitation, water and sediment discharge data for the period from 1970 to 1998 were collected, refined and analyzed. Then, appropriate models were extracted using the concept of dynamic modeling and subsequently the pertinent models were recognized based on the coefficient of determination and estimation error criteria. The results indicated that the monthly classification of the data led to achievement of better outputs as compared with those obtained from either no classification or seasonally made groups. It was also found out that the daily sediment was not affected by the precipitation, sediment and water discharge occurred respectively before ten, nine and ten days. In other words the data belong to events previous to days before the mentioned time could not affect the output of the models. It was also implied that the daily discharge highly affects sediment concentration during the same day. The coefficient of determination and error percentage of estimation in all the suggested models were respectively higher and less than 0.80 and 40% which may verify the application of such models in daily sediment estimation in the study area.

Design flood is an indispensable criterion in many water projects. Unfortunately, many of developing countries including Iran are faced with lack of sufficient recorded hydrologic data. Thus, in order to cope with data scarcity and study ungauged catchments, application of developed empirical models based on other gauged catchments is a common strategy used by hydrologists. The present research work is an effort to evaluate a number of ten general empirical models for flood estimation with different return periods. The models include: Dicken, Creager, Gray, Bremner, Waitt, Inglis, Cramer, Murphy, Ocornell and Cooley. The models have been tested in the major Iranian watersheds namely the Caspian Sea basin, the Persian Gulf and Oman Sea watersheds, the Uromia Lake watershed and the Central Deserts catchments. The results highlight that the Bremner Model is best for shorter return periods in Caspian Sea watershed whereas Murphy Model can act better as a general model over there. In the Persian Gulf and Oman Sea watersheds, the Dicken Model with an exponential form shows better results. However for short return periods the Gray model is better. In Uromia Lake watershed all models except Gray are applicable. In the watersheds of the Central Deserts, for shorter return periods the Murphy Model gives better results whereas for longer return periods Cramer is the most suitable. The present study shows that the most suitable range for study area varies from 1400 to 2400 Km2.

Monthly discharge is one of the most important factors to be considered in designs and hydrological works. Some basins are not equipped with needed hydrometric equipment. In such a case average monthly discharge could be estimated from regional monthly water balance models of representative basins. These models are of two types: P and PE. In P type the only input is precipitation and whereas PE type the input series are precipitation as well as potential evapotranspiration. In this study, PE type models were used in 12 basins in the semi-arid climate of Azarbayejan as wellas North of Khorasan province in Iran. Following collection of data in temperature, precipitation and average monthly discharge in these basins, the potential evapotranspiration was calculated using Thornthwait formula.Remaining parts of water balance equation including: Actual evapotranspiration, soil moisture supply of basin in each month and later months are estimated from Thornthwait model .Then, by regarding the logical relationship between parameters, the regression relationships between various parameters in water balance are established. The models are analysed at 5% confidence level. The results of the tstudent-test showed that difference between observed and estimated runoff, from models, wasnot significant and thus by using the monthly water balance models, the series for mean monthly discharge could be generated.

Effect of bramble (Rubus fructicosus L.) on some characteristics of oriental beech (Fagus orientulis Lipsky) seedlings was studied in a 700m2 canopy gap of beech stand, located in the north ofIran. For this purpose, in the center of the gap, two treatments with 3-year-old man-made seedlings were examined at four replications. In each replication, 36 seedlings were planted with 50cm x 50cm spacing. In one treatment, removal of bramble and at the other one, keeping of bramble (control) was conducted. The results, at the end of the second growing season (after plantation) revealed that seedling survival was greater in control (71 %) than in bramble-cut area (46%). Shoot growth wasn't statistically different in the two treatments (22.0 cm and 23.4 cm, respectively). Vitality was affected by the treatments where near to 80% and 60% of seedlings, respectively with bramble and without bramble, were in moderate to good condition while the rest were slightly to severely paled. Generally, it can be deduced that in the relatively-opened canopy of beech stands, during the 2nd year of plantation, survival as well as vitality and shoot growth are not declined under bramble cover. In case of obtaining similar results, through repetition of such investigations in different beech stands, avoidance of practice of bramble cleaning during the first two years can be recommended, and the costs thus avoided.

In order to determine the most suitable shade rate for producing beech (Fagus orientalis Lipsky) seedling in a mountainous nursery, three wooden shelters with shade levels of 33,50, and 60% as wellas one with full light were examined in a completely randomized block design with four replications. It was carried out in Urimelk nursery (located at 1550 meter altitude), of Farim forest company, north of Iran.This study indicated that after one growing season, effect of shade on survival rate was greater than 90%. Difference among hight growths was significant too. Right growth increased with increasing light, but shade levels did not produce significant differences in growth of collar diameter.

In this research, a part of forest stand in two protected and no protected areas have been compared for quantitative factors. Initially the similarity of these stands using aerial photographs in 1:20000 scale of 1968 was studied and the similar stands were chosen. Then 92 line samples with a network size of 150 x 300 m in noprotected parts of stand are sampled out and compared with other 92 line samples recorded from protected areas. From quantitative factors, basal area of stand and number of trees perhectare. were determined. The number of trees and basal area in protected area was significantly higher than that in nonprotected forest stands.

This study was conducted to determine the resistance of Fenneropenaeus indicus to osmotic stress. PL-1 of Fenneropenaeus indicus were reared for 15 days on Artemia urmiana nauplii enriched with various levels of n-3HUFA. On days 10 an 15, their resistance to somotic stress, transfer from 33ppt to 0 and 6 ppt, for 30 and 60 minutes were analyzed. In PL-10 and PL-15, Postlarvae fed with Artemia containing 33/8 mg/g DW n-3 HUFA and DHA/EPA ratio of 2/5, had a significantly higher resistance in 80% and 100% reduced salinity (P<00.1). Also, there is positive and significant correlation observed between DHA/EPA ratio in Artemia and osmotic stress resistance (Oppt) in PL- 10 (r=0.99, P<0.05) and PL-15 (r=0.96, P<0.01). On the other hand, a significant crrelation was found between the osmotic stress resistance of PL-10 in 6 and 0 ppt for 30 minutes as well as the survival recorded in five days later in each tank (r=0.87, P<0.05; r=0.85, P<0.05). It is concluded that resistance to osmotic to osmotic stress is a rapid, inexpensive and valuable quality indicator for postlarval penaeidae shrimp.

In this research work the effect of cold storage on the quality of cultured and sea shrimp from Persian Gulf was investigated for 120 days. According to a time schedule, the samples were tested for changes in their organoleptc properties, total count of bacteria, pH, Total Volatile Nitrogen (TVN) and Peroxide value rv) The Results indicated that taste, smell, flavor and colour of cultured shrimp remained natural for 90 days with its bacterial count dropping from 2.49x103 to 7.7x101 colonies/g. But after 120 days of cold storage pH and TVN increased from 7 to 7.7 and 14.4 to 31 mg/100g. respectively. After 60 dyas of cold strage pv increased from 1.7 to 2.7 milliequiyalents/ 1000gr., then started to break down. The results for sea shrimp indicated that taste, smell, falvour and colour remained natural only for 30 days. After 120 days of cold storage, total bacterial count and pH changed from 2.21 x 104 to 2.01X102 colonies/gr., and 7.1 to .1.9. whereas, after 60 days of cold storage TVN changed from 25.2 to 31 mg/100 gr with pv increasing from 1.9 to 3.1, then starting to break down. After, 20 days in cold storage pv was reduced to 2.4 miliequivalents/1000gr.

A large amount of rain water is transferred to reception mainstreams (e.g. surface and groundwater) in urban areas due to the increased impermeable surfaces. Urban catchment's water that is produced by precipitation or snow melting is considered as one of the most important non-point pollutants.In this investigation, having discretely sampled the output drainage in 13 precipitation events in one of lsfahan catchments during autumn/winter, 2002/2003, 10 qualitative/quantitative parameters were measured to assess the general quality. Modulating the drainage pollution amount (using multivariate statistics) nitrates, total suspended solids, chemical oxygen demand and average discharge factors were considered as the main regression factors. Modulating input data through which a regression model of the least error (0.009) an highest correlation coefficient (0.998) was designated to assess the amount of output drainage pollution. Input parameters of the model were total suspended solids and chemical oxygen demand. To assess the model accuracy, error indices were estimated using two data groups that was not which included in modulating which indicated the qualification of the model for the next stage. Using this model, total pollution amount of output drainage can be calculated for future events through measuring two input parameters. Also, another regression model was presented based on precipitation characteristics, which can be readily used, but of less accountancy. These results can be useful for water resource managers, urban programmers and those responsible for environment to control Zayande Rood River pollution, maintain environmental circumstances and carryout reasonable urban catchments management.

In order to study the feasibility of the use of Lignocellulosic fibers in the manufacture of fiber-polymer composites, two types of these materials namely, kenaf and bagasse were mixed with polypropylene at 10, 20, 25 and 30 percent by weight. 2% MAPP was used as the compatibilizer and 1% DCP was used as the promoting interfacial agent. The results indicated that tensile strength, elongation at break and impact energy application declined whereas tensile modulus and hardness increased as compared with pure polypropylene. From the two filler types, kenaf fibers had better improved properties of composite materials. But this difference was not significant. Due to processing convenience and good dispersion in the polymer matrix of bagasse fibers, use of this materialist recommended. Regarding a lack of significant difference in the reduction of properties due to an increase in filler content from 10% to 30% and the increase in tensile modulus as well as hardnessa, 30% fiber content is recommended for application purposes.

Wood logs were supplied from Mamasani, Fars Province, from a population of planted eucalyptus trees. They were cut into 7x7x100 cm samples, and dried to below 20% moisture content.A split plot design was used for the experiment. Three impregnation methods namely Bethel, Rupping and Double rupping along with three preservatives as against control samples were employed. A creosote and two other water soluble preservatives were prepared with proper pH using AWPA standard. Results are indicative of reactions of wood as well as internal wood elements to impregnation. A decrease was observed in the overall shrinkage in the treated samples. This was more pronounced in the Bethel creosote method. This indicates the stabilization of wood dimensions as a result of impregnation. Some reasons for this phenomenon could be cited as trans attachment of wood elements, subsequent drying in double drying process, and irreversible swelling. The specific gravity is less in treated samples as compared to control, this being more pronounced in the case of double rupping, and treated samples. with preservatives; chromium, fluorine and arsenic. This could be due to minor cracks on wood, microscopic cracks (inner layer fracture, cell wall ruptures, etc), increase in dimensions (of irreversible nature), and inflation of wood elements, double drying stresses and unexpectable leaching. Milder treatment methods such as rupping and use of less volatile elements of chromium, copper and arsenic (CCA) are preferred over others.

The objective of this paper is to develop a method for selecting the most suitable location for establishing wood industry unit. Decision making is examined within the framework of benefits, opportunities, costs, and risks (BOCR), called the merits of the decision. A hierarchy is developed to prioritize the BOCR in itself, while Analytic Hierarchy Process ratings approach is applied to evaluate the hierarchy. It is recognized that benefits, opportunities, costs and risks are often not emphasized proportionately when making a decision. In fact, it is vital to design a decision supporting system to evaluate them in terms of the values attached to by decision-making person or organization. A control hierarchy is then created and prioritized using the AHP to evaluate the "control criteria" of the system. There are a total of 18 control criteria in the system each controlling a decision network evaluated while using the Analytic Network Process (ANP). This method was applied for a real case in Iran. There were six potential locations, or in fact alternatives found for the decision network. The final synthesis of the system indicates Baneh in the province of Kurdistan as the best choice available.

Randomized samples have been prepared from local Old Newspaper (ONP) and Magazine (OMG) with their specified mixtures having been repulped, deinked and subsequently bleached with hydrogen peroxide. Three levels of paper mix (100, 70/30 and 50/50 percent of ONP/OMG), 2 types of chelating agent (DTPA, EDTA), and 3 levels of calcium ions (1, 1.5 and 2%) have been studied as variable parameters. Brightness values of the deinked pulps, before and after bleaching, and optical and mechanical properties of bleached deinked pulps have been measured and compared with local hardwood CMP pulp.The results have shown that although the brightness of CMP pulp is higher but its mechanical properties are lower than deinked pulp at similar freeness. Normalization results have shown that the deinking treatment using 50/50 ONP/OMG, EDTA and 1% calcium ion charge won the highest score or the best optical - mechanical properties as compared to local hardwood CMP pulps. As a result, it can be predicted that the bleached deinked pulp prepared under optimum conditions as indicated in this research, can be used as a mixture furnish with local CMP for making newsprint paper.

The Khan-chay watershed in Tarome-olya of Zandjan province with an area of 20243 hectares is located in the north of Zandjan. The lowest and highest altitudes range from 400 to 2763 meters above sea level. The mean annual precipitation varies from 700 mm at the top of the mountains to 200mm in Ghezel-uzan river area.For a floristic study of the area plant specimens were collected and identified. The life forms as well as geographical distributions of the species were determined. Flora in this region include 57 families, 195 genera and 310 species. The larger families are Compositae (45 species), Papilionaceae (37 species), Graminae (34 species), Labiatae (25 species) and Rosaceae (20 species), respectively. One hundred and eighty nine species are new records for the flora of Khanchay. Life forms include Hemicryptophytes (56.8%), Therophytes (12.6%), Chamaephytes (11.6%), Phanaerophytes (11%), Crytophytes (7.7%) and one semiparasite specimen. Phytogeographical elements in this region were determined as: 71/3% Irano-Turanian, 8/7% Irano-Turanian and Euro- Siberian, 5/5% Irano-Turanian and Mediterranean, 4/5% Irano-Turanian, Mediterranean and Euro- Siberian, 3% Cosmopolite, 1/6% Irano-Turanian, Mediterranean and Saharao-Sindian, 1/3% Eurosiberian and /3% Irano-Turanian and Saharao-Sidian.