IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2005 | Volume:58 | Issue:3|Papers Count:28

An estimation of reservoir capacity substantially depends on river discharge. Either an overestimation or an underestimation of this parameter can bring about negative economical as well as social consequences. Generally, stream flow data generation is accomplished, using the stochastic methods. Number of parameter in these methods, especially in monthly scale, will cause a considerable error of estimation. In this study, a nonparametric method called kernel density function was employed to generate the monthly stream flow for Dez River. Method for choosing the best simulation, among 50 monthly generated series, is based on an evaluation of mean absolute error (MAE) factor. A comparison between the most proper series and observed values of stream flow indicate a maximum difference of 11.6 % that can be acceptable to be observed in a problem. This approach can be proposed for generation of long-term monthly stream flow data for any river. This method especially allows, in cases of unavailability of long-term data, for reasonable decision-making in surface water planning as well as in future management of water resources systems.

A significant portion of precipitation falls as snow in mountainous regions with the snowmelt being the main source of water supply in low flow seasons, ground water recharge, and even sometimes the main cause of flooding. Information on the timing, magnitude, and contributing area of snow accumulation and melt is required for successful water resource management. Many studies have indicated that snow cover is an important variable for runoff modeling and forecasting, particularly in mountainous areas. Temporal and spatial variability of snow cover could be known as an important index of snow cover characteristics at the watershed scale.The major objective in this research is to investigate the effective regions in accumulation and persistence of snow cover as well as ranking of upland hydrological units based on the contribution of snowmelt to the runoff. This information is useful in developing snowmelt simulation and forecasting models. In this research snow cover variability in space and time was simulated using remote sensing as well as meteorological analysis. Contribution of snowmelt to runoff on upland hydrologic units was determined using a water balance model along with regional relationships. Also critical temperature, which is one of the most important variables in snow studies, was determined using remotely sensed and synoptic data.

Annual rainfall data related to a 43-year period from a number of East Azarbaijan climatological stations were employed to analyze and model the precipitation toward a determination of drought as well as wet years. Results indicate the occurrence of different intensity drought phenomenon in all stations. As reqards the classification of the annual wet and dry seasons, normal precipitation among various alternate dry and wet years can be observed with the normal years having more stability and continuity as compared to wet and dry years. The Standardised Precipitation Index was recognised as a better and more accurate model as compared to the other models i.e., Nitzche model, and Dependable Rainfall (DR) applied in this research.

Prevention of sediment movement in the taking area is a fundamental basic task. For source studying of Rafsanjan eolian sediments, step by step method (Ekhtesasi-Ahmadi et al.) was employed. This study is carried out in two stages: direction finding and location finding. For direction finding of taking sector, first through quesitionnaire Fill up informations on local winds were gathered. Then satellite images at two periods were compared through these images as well as field investigations, the erg morphological map was prepared. By studying wind regime and windrose drawing, the erosive winds were recognised. After recognition of taking sector (west and southwest sector), the location-finding phase was started. In this stage through geomorphological studying of taking sector and sampling into facies, the mineralogical and morphoscopical studies of sand dunes and taking sector sediments were done.At last with due attention to reasonings such as: the direction of Seif and Barkhan dunes (southwest-northeast), the settlement of Zibars in the west and southwest of erg, high intensity of energy for west and southwest winds, the existence of heavy minerals as Hematite and Amphibole in sediment samples, large median of samples (240 microns), the skewness of some samples towards coarse particles as well as low roundness factor (of taking sector samples), it was found that the sources of eolian sediments are close (<20 km) and inctude the followings:rangelands, abondoned farmlands and pistachio gardens on the east and southwest plains of Rafsanjan, the barelands or poorly covered grounds on the east pediments of Rafsanjan as well as beds of Shoor, Shahzadeh Abbas and Kabootarkhan rivers.

In order to determine the rate of litter decomposition in Alnus subcordata in two alder stands, litters from Vaz and Asalem with different parent materials were collected in autumn. Litters from each region were put in four vases for 7 months in laboratory conditions. Sampling was done within every 21 days. Nitrogen and carbon content were measured in each interval. On the first day, the comparative study between the two regions showed that there existed no significant difference between C and N content in litters.The amounts of N were 2.49 % and 2.62 % in litters of Vaz and Asalem respectively. Carbon content was 13.35 % in Vaz and 33.? % in Asalem. Rate of carbon variation indicated no significant difference in the two regions. Rate of nitrogen and CIN variation exhibited a significant difference in the two regions. CIN was reduced from 17.38 to 10.35 and from 15.12 to 10.67 in Vaz and Asaiem stands respectively.

In order to study the effects of some environmental variables on the quantitative and qualitative characteristics of large-leaved lime (Tilia platyphyllos Scop.) in the forests of the western parts of Mazanderan province, 9 experimental sites were selected. Within each site, three elevations were identified. Also in each site three plots, each of one hectare area (l00×l00m), in total 27 plots were establishd. Observations as well as experimental results indicated that large-leaved lime extends in a wide range of environmental conditions. This species is distributed from low elevations to high ones and in different exposures; especially northern, eastern and northeastern slopes. The results also revealed that large-leaved lime grows in semi-deep to shallow soils with a medium amount of nutrient content. In most sites, soil texture is clay to clay-silt with pH varying between 5.9 and 7.6. Average annual precipitation varies between 1100 and 1311 mm, with average annual mean temperature varying between 8.1 and 15.2°C.Categorization of sites was accomplished through hierarchical cluster analyse and based on the effects of environmental variables on the quantitative and qualitative characteristics. The quantitative and qualitative characteristics play an important role in site classification because of being affected by environmental variables.There is relationship between ecological characteristics (soil, climate, altitude and slope sides) and quantitative characteristics (diameter at breast height, diameter of crown, total height, height of first branch, as well as height of bi-branch) and qualitative characteristics (stem bending, convolution, as well as stem symmetry of crown).

The main aim in this research was the studying of variations in soil physical and chemical properties as related to tree ecologicai groups (tree types) in Nam-Khaneh district of Kheirood-Kenarforest. To determine the ecological groups, square plots of 50×50 m (2500 m2) were established on each of which trees with more than 7.5cm diameter at breast height (dbh: 1.3 m above the ground level) were assessed. The basal area for each tree species in each sample plot was calculated, then using these variables, classifications of the sample plots was carried out through TWINSPAN (Two Ways Indicator Species Analysis). On the base of this, four tree groups were determined. In order to select sites for soil study through sampling, the forest was divided into landform units based on differences in altitude, slope and aspect. Within each landform unit, every tree plot was compared with its two nearest neighboring plots on the basis of their species compositions using the Sorenson index. Eighty five sample plots were selected, for soil study through soil profiles, from among the original 325 tree plots. For all soil samples, pH, texture, bulk density, percent organic carbon, N, P and lime were determined. In order to study relationships between soil properties and variations in tree compositions One-way ANOVA, Deternded Correspondence Analysis (DCA) were used. The results indicated that among studied soil properties, percentage of organic carbon, C/N ratio, soil texture, and soil bulk density were the most significant factors that varied and determined the distinction among tree ecological groups (forest types).

Land, as Location as well as a production factor plays an important role in economic planning. There are numerous constraints that affect land allocation to a certain category of land uses. Previous studies have indicated the capability of Linear Programming (LP) to solve resources location as well as allocation problems. Land as well as other resources are allocated to different land uses due to their scarcity and comparative advantages in different production procedures.In this study a model has been established for 28173 ha of Keleibar-chai watershed; including 53 variables and 62 constraints. The study area has been classified to homogenous sub-regions, according to their natural potential to produce different goods and provide numerous services. Homogenous areas have been defined as a group of constraints in the model.The model explains how an LP Model could be related to location and economic constraints. In the region, rangeland, fodder cultivation as well as related processing industries are economically more efficient than dry farming of wheat, barely and orchard management. About 700 ha have been allocated to hay production and irrigated barley cultivation. This will supply enough complementary fodder to support 12521ha of the region for range management. It may forego some area of the protected forest to become dedicated to rangeland in the process of land planning in the region.

A recirculating aquaculture system was designed, consisted of a fish tank (110 L×84 W×100 D cm), three hydroponic troughs (110L×30 W×5D cm) and a water pump with the capability of pumping 30 liters of water per minute for circulation of water through the system. Hydroponic troughs were installed over the fish tank with in a distance of 20 cm. Each fish tank was filled with a volume of 640 liters of water and then 75 juveniles (20±0.02g) of red tilapia were introduced in each tank to be reared for a 3-week period. The fish were fed a floating pellet feed, containing 24% protein, twice a day at 09.00 and 18.00. The mean amount of supplementary feed was 2025 g in each fish tank during the experimental period. The fish attained mean individual weight of 44.73±0.35g at harvest time and the remaining wastewater or residual in each system was used as a medium to supply nutrient needs of 42 one-week old lettuce seedlings in a culture system. Lettuce seedlings were cultivated for a 5-week period. The yield in lettuce was 2017±197g at the end of the experiment. The concentration of nutrients in water were determined after the harvest of fish as well as the lettuce seedlings. On average, lettuce seedlings could intake 3.20, 73.76, 7.97, 3.48, 5.01, 4.72, 1.48, 8.98, and 0.28 % of feed's Fe, Mn, Zn, Cu, Ca, Mg, P, N and K, respectively. Results in this study indicated that aquaculture wastewater can be used as a suitable nutrient supplying solution for lettuce culture in a NFT (Nutrient Film Technique) system.

Among the 40 commercially exploited fish species in the Caspian Sea area, the six species of sturgeon are unique. Persian sturgeon is one of the five living species in the family of Acipenseridae in the southern parts of the Caspian Sea. Study on assessment of commercial sturgeon stocks is indispensable or the effective fishery management of the spawning sturgeon population. The aim of present study was to investigate age, sex and length compositions in Acipenser persicus and to define the relationships between length, weight and age of the fish in the southeast of the Caspian Sea during summer catching.This study was carried out at Turkman Sturgeon Fishery Station. in 200I. Samples were collected from 80 specimens of A. persicus (31 males and 49 females). Fork length as well as total weight of the captured fish were recorded. Age determination was carried out using first pectoral fin ray.Results indicate that age, fork length and total weight means in females were higher than those in males (P<0.05, P<0.01, P<0.01, respectively). 61.25% and 6.25% of captured fish were the females and immature fish respectively. Sexual maturity was more than 19 and more than 17 years for females and males, respectively. The weight of fish increased with increase in fork length (P<0.01). By increase in fish age the fork length and weight increased. The estimated linear regression functions for length and weight growths were statistically significant in A. persicus in the southeast of the Caspian Sea (P<0.01).This study shows that overfishing status is prevailing in females which can be reduced through a biological conservation plan. The correlation between fork length and total weight, length enlarement and increase in weight are due to feeding factors, habitat environmental conditions such as temperature and oxygen, as well as food composition provided to animals.

Industrial factories, in their different sections, produce diverse solid wastes that often end up with adverse environmental effects, causing various management and disposal problems. Nowadays, the reduction of these effects is a significant challenge to the industries in large, car manufacturers in particular, in achieving the goal of sustainable growth. Iran Khodro Company, as the country's largest car manufacturers, generates solid wastes that would adversely affect the environment, if not properly managed.In this research, the trimming and finishing parts unit of Iran Khodro, as one of the waste generating units, has been studied, the quantitative as well as qualitative analysis of the wastes having been carried out to come to an adequate management and efficient disposal channel for the wastes. The crude material used during different processing activities in this unit include fabrics, PVC, nylon, timbers, wooden fibers, ferric profiles, and last but not least paints.The results in this study indicate that the quantitative and qualitative analysis of the wastes brings lead to the necessary cognition for waste management including: economy in crude material consumption at the onset, waste recycling, and efficient trimming of the wastes.

To investigate the precipitation of heavy metals in Anzali wetland and evaluate its refining performance this study was carried out on the wetland. Monthly samples of sediments from 15 stations including inlets, outlets and some internal locations in the wetland were collected and analyzed over a period of six months (July - December 2002). Sediment samples were analyzed for six metals of Cr, Cd, Pb, Zn, Cu and Ni. Wet digestion method was employed for extraction of metals in samples by and through a solution containing HNO3 and HCL. Atomic Adsorption Spectrophotometry was employed for measurement of the heavy metals. Statistical methods, including analysis of variance (ANOVA), correlation and Cluster analysis were used for analysis of the data. The results indicated that concentration of heavy metals present in sediments (collected from different stations and at different times) were significantly different. Among the metals studied, Zn was of the highest concentration Heavy metal concentrations in stations 11, 12and 13were lower than in other stations. Sediments in station5 contained the highest concentrations of heavy metals among all sediments. It can be stated that concentration of heavy metals decreases with an increase in the distance from delta of rivers entering the wetland. This is due to the role and performance of wetland chemical contents in reduction of pollutants, the self-purification action of wetland as well as precipitation of heavy metals at the beginning of the entries into the wetland.

Heavy metals are considered as dangerous environmental pollutants that by entering the food chain, pose serious health threats to humans, plants, as well as other animals. Especial plant species can grow on heavy metals contaminated soils and uptake a large amount of these metals. Use of these plants as a method of remediation of polluted soils, known as phytoremediation, has attracted a great deal of attention. In this research work concentration of lead in the soil, as well as in five plant species, namely Acantholimon sp., Noea mucronata, Scariola orientalis, Stachys inflata and Stipa barbata, around Irankouh lead and zinc mine in southwest of Isfahan, was analyzed. The statistical analysis of data was done in a randomized incomplete block design. The results indicated that the difference between the concentration of lead in the shoots of plant species was significantly different (p<0.05) while in the roots it was not significantly different (p>0.05). Among the studied plant species, Stachys inflate exhibited a maximum accumulation of lead (mean concentration of 311.8 mg/kg) in its shoots. The concentration of lead in the shoots of plants was shown to negatively correlated with soil pH (r= - 0.488**) while being in positive correlation with total (r= 0.726**) available lead concentration (r= 0.412*) in soil.

The Effects of some process variables on P. nigra APMP pulp yield and brightness were investigated. Wood samples were prepared from poplar plantation fields in the vicinity of Maragheh Paper Company. Fiber dimentions such as average fiber length, diameter cell cavity and fiber wall thickness were assessed as 853, 22.66, 15.16 and 3.74 microns, respectively. For making APMP pulp, different chemicals namely sodium hydroxide (6 and 7%), hydrogen proxide (5 and 6%) diethylene triamine pentaacetic acid (0.5%) and sodium silicate (3.5%) (based on O.D chips) were used. Based on the preliminary chemical treatment results, chips treated with preheating of 20 minutes, impregnation times of 20 and 75-105 minutes in first and second stages, pulp conssistency of 34-36 % and 23-25 % in the first and second stages of impregnation, respectively, percentages of caustic charge in 3 levels of 40, 50 and 60% in the first impregnation stage, percentages of proxide charge in 3 levels of 20, 25 and 44% in the first impregnation stage, percentages of diethylene triamine pentaacetic acid in 2 levels of 60 and 75% as well as percentages of sodium silicate of 50% in each stage of chemical impregnation, were selected as the process conditions. The APMP pulp brightness and yield obtained in the 24 treatments, were in the ranges of 71.7 -78.6 % and 84.17 -93.46 %, respectively. The final results indicated that by using optimum process variables such as total caustic and proxide charges of 7 and 6% respectively, percentages of caustic, proxide and diethylene triamine pentaacetic acid in the first impregnation stage of 60, 20 and 75%, consistency of 34 and 23% in the first and second stages respectively, It is possible to produce APMP pulp of high brightness in an acceptable yield range.

Application of High Yeild Soda pulping for the production of unbleached (HYS) as well as bleached (HYBS) pulps from fast-growing poplar species; including two species; P.nigra var betolifolia and P.euroamericana No. 561/41 at two diameter classes (15 & 20 cm) is studied.Anatomical measurements revealed average fiber length, fiber diameter, lumen diameter and cell wall thickness at 978.63, 23.20, 15.45 and 3.90 µm respectively.Results in pulping and paperrnaking studies indicated that the treatment involving P. euroamricana species at a diameter of 20 cm, (using HYBS) is superior to the others.Hand sheets made from the superior treatment possessed a tear index of 4.214 mN.m2/g, breaking length of 3.66km and burst index of 3.17kPa.m2/g. The results in optical studies indicated that highest brightness (59.52 ISO) as well as the lowest opacity (95.22) were obtained through this treatment as compared to other ones.

In this investigation, particleboard manufacturing with the use of Methylene Diphenyl Diisocyanate (MDI) adhesive has been studied. In order to evaluate the bonding efficiency of MDI with inorganic materials, paper sludge of Mazandaran wood and paper industries (CMP, NSSC), containing inorganic about 28 percent, was mixed with wood chips at 0, 15, 30 and 45 percent by weight. Single-layer partic1eboard as well as three-layer particleboard (paper sludge as a surface layer) were produced. Methylene Diphenyl Diisocyanate (MDI) adhesive was applied in two levels of 3 and 4 percent. Other factors such as, press pressure, press time, mat moisture, thickness and board density were the invariable factors. Physical and mechanical properties including bending strength, shear strength, thickness swelling and water absorption after 2 and 24 hours of immersion were tested. The results revealed improvement in all board properties resulted from more adhesive use. Using more paper sludge caused a slight decrease in shear and bending strengths while a slight improvement in thickness swelling. The lowest thickness swelling was observed in the three-layer particleboard.

In order to find a non-wood raw material for use in particleboard manufacturing, a feasibility study using sunflower seed bark mixed with wood particles was performed. Percentage of sunflower seed bark in mixture (0, 15 and 30 %), amount of urea formaldehyde resin (9,11 and 13 %), and press time (5 and 7 min) were selected as variables, other factors being kept constant. A factorial design was used for conducting the experiments. Physical and mechanical properties of manufactured boards were determined based on DIN-68793 standard. Anova method was employed to analyse the effects of variables on manufactured boards. Results indicated that adding sunflower seed bark to wood particles as much as 15% not only has no negative effect but causes an increase in modulus of rupture, modulus of elasticity as well as an increase in internal bonds of boards as compared with boards made of only wood particles. However, water absorption in boards increased to an insignificant extent. Adding sunflower seed bark to wood particles (more than 15%) negatively affect affected board properties. Analysis of interaction effects of variables on board properties revealed that an increase in amount of resin up to 11 % as well as in press time to 7 partly minutes partly neutralizes the negative effects. Grouping the experimental data while using Dunkan method was indicative of the fact that an optimum condition for manufacturing particleboard while using a mixture of sunflower seed bark and wood particles is to add 15% sunflower seed bark to the mixture, use 11% urea formaldehyde resin and employ a pressing time of 7 minutes.

An autecological study of crested wheatgrass was carried out in west Azarbaijan province from 1977 to 2001. The objectives included: 1- preparation of a habitat map 2- phenology study 3- a determination of the relationship of crested wheatgrass with land form (slope, direction as well as height), geological formation, soil and finally 4- determination of density, canopy cover, companion species, root extension as well as biovolume. A west Azarbaijan catchments were selected as case study units. Study of geographic distribution of crested wheatgrass was done in each catchment, considering geology formation and land from. Phenological studies were done at different intervals in Bazargan, Sero (kuh-e-Tapik) and Salmas (Tamar mountains). The results demonstrated that crested wheatgrass was found in all Azarbaijan's catchments from an elevation of approximately 800 to 3575 meters above sea level in all geographic aspects. The campanion species are: Astragalus parrowianus, Bromus tomentellus, Achillea millefolium & Stachys schetschegleevii.The time of initial growth, vegetative growth, heading, flowering, seed ripeing and seed shedding of crested wheatgrass in Bazargan are respectively mid Marh, mid May, late May, mid June, late July and early September. The density, canopy cover and root extending in Ag. Cristatum in Tapik, Tamar & Bazargan are (1800, 1200, 1100 bunch per hectare), (3, 2, 2 percent) & (130, 80, 85 centimeters) respectively.The geologic studies indicated that the main habitats of Ag.criatatum are Colored melange as well as Qom formation. It grows best on medium-textured soils, from sandy loams to clay loams. Crested wheatgrass does riot grow well in loose sandy soils, heavy clays, or saline soils.

The effect of salinity stress on seed germination in 3 rangeland species of S rigida, S.richteri, S.dendroides and to determine the salt tolerant species was investigated in this study. All three species are suitable for grazing as well as reclamation of arid and semi arid lands. This research was conducted using a factorial experiment based on CRD design with 4 replications. Experimental treatments included a combination of three species along with 13 salinity levels of 0,50,100,150, 200 ,250 ,300, 350 ,400 ,450 ,500 ,550 and 600 mM concentrations. The results indicated that S.dendroides and S.rigida were more tolerant than S.richteri. While S.dendroides and S.rigida were tolerant to 600 mM, S.richteri was tolerant only up to 350 mM. With increase in salinity germination percentage and germination rate were reduced with the maximum germination occurring at the lowest salinity level. Increasing salt concentration up to 200 mM did not significantly decrease radicle length in S.dendroides, but in S.rigida with an increase in salt concentration (up to 50 mM) radicle length increased. Salinity increase in S.richteri cauased decrease in radicle length. So S.richteri is shown to be more sensitive to high salinity levels at germination stage as compared to the other two.

This research was carried out to find the effect of grazing intensity on soil organic matter, carbon and nitrogen. For the purpose, Lar region in North West of Haraz road, 84km from Tehran, was selected. By field inspection, three different areas of Reference, Key, and Critical were identified. Information on soil was collected as per random-systematic method. Soil samples were obtained from two horizons (0-10cm,10-30cm),in any soil profile and for three times during the grazing season. Twenty soil samples were obtained from each horizon during the three study periods. Data analysis was carried out using a split - split plot design. First, data were tested for normal distribution. Analysis of variance was used to test the treatment effects. Duncan test was employed to separate the means. Results indicated that carbon, total nitrogen and organic matter decreased with increase in grazing in intensity, but no significant difference was observed in C/N ratio in the three study areas. Values in these factors were higher for surface layers. This research revealed the fact that heavy grazing jeopardizes the sustainability of the ecosystem by creating unfavorable changes in soil chemical characteristics as well as in vegetation vigor and endurance.

Using vegetation indices (VI) for an inventory of natural ecosystem has been developed over the past decades. Also these VIs have been observed to have a suitable correlation with vegetation parameters. However, to apply VI over a continuous span of time some considerations should be taken into account. In order to study the capability of multi-temporal Landsat 7 (ETM+) data in estimating vegetation parameters, different year images in a steppe region in Markazy Province were used. Information of regarding canopy cover and production of different vegetation forms were collected through 60 2×2 plots.Geometric correction of satellite images was conducted through ground control points with an RMSE of less than 0.5 pixel. Then to eliminate the effects of looking geometric situation as well as to make photography situation in different years uniform, radiometric correction was conducted, and digital number of each pixel converted into spectral reflectance. In the next stage, appropriate VI for arid regions and atmospheric correction VI in sample plots were assessed on the basis of spectral reflectance. Results of correlation survey between VI and vegetation parameters indicated that ETM5, ETM7 bands as well as TSAVII, GEMI and ARVI indices are in significant correlation with canopy as well as with production in different vegetation forms. Among VIs, GEM! exhibits the highest coefficients, of 0.43, 0.59, 0.63, and 0.55, for grass cover, shrub cover and total vegetation cover as well as for production respectively. According to the results in this research this conclusion can be drawn that using spectral reflectance of multi temporal data to estimate vegetation canopy cover and yield in arid regions can yield more acceptable results. Employment of atmospheric correction indices (GEMI) to decrease changes in atmospheric conditions in different years is necessitated.