Evaluation of floodwater spreading for groundwater recharge in Gareh Bygone Plain, southern Iran

The overall objective of this dissertation was to evaluate a floodwater spreading system that is installed in 1981 at the Gareh Bygone Plain, southern Iran for recharging the groundwater table. As the spatial and temporal distribution of the evapotranspiration (ET) was a necessary input, an energy balance model “SEBS” was calibrated for the study area and its results were cross checked with water budget results to obtain the reliable ET maps. TDR method was then evaluated for the original stony soils and a set of new coefficients were generated for these soils and the new equations for cable length correction for accurately converting the soil permittivity to ɵv. Two methods of recharge assessment “saturated zone” and “vadose zone” were further employed to determine the ratio between total and artificial recharge independently. In saturated zone, water table fluctuation and water budget concepts were combined and the effect of flooding event on groundwater table was substantiated and the recharge was assessed for a selected hydrological year. In vadose zone, three experimental well were installed with the depth of ~30m and one was equipped with the calibrated TDR probes and the time series of soil-water data were collected for the three years successively. Soil water budget method and a modelling approach by Hydrus 1d was used independently to simulate the water movement and assess the recharge after a flooding event. Calibration of the H1D model by inverse solution resulted in RMSE values of simulated vs. observed ɵv of 0.02 to 0.05 (m3 m-3) for different subsurface layers. Calculations, indicated that out the 51.8 cm of ponded floodwater during the 16 January to 23 August 2011 period, 29.6 cm of cumulative recharge occurred, showing an efficiency of 57%. Two independent approaches suggest that 57 to 61% of input water effectively flows to the groundwater table. The optimized hydraulic parameters of the representative layers in aquifer profile, can be applied in future studies when attempting to up-scale our findings

Habitat Classification of Maharlu Wetland Using MedWet Classification System

Identifying the different habitats in wetlands is essential for their protection. This research was carried out with the aim of classifying habitat areas of Maharlu wetland in Fars province using MedWet, Mediterranean Wetland Habitat Classification System. Information on dominant vegetation cover, soil, and hydrology of the wetland was prepared using field surveys. The data on the water regime were obtained with quarterly satellite images from 2016-2019 in remote sensing media using ArcGIS. Sampling was performed for wetland plants and lake bed outcrops from 39 stations in May 2020. Plants were identified and classified on the basis of being an annual or perennial presence and submerged or floating. By stacking this information in ILWIS, different habitat zones were separated. Each was then specified using habitat international standard codes, and habitat maps were prepared. In total, 42 habitats were identified in the Maharlu wetland. The most prevalent habitats were palustrine–emergent–persistent–seasonally flooded–Mixosaline– (P-EPSX-) (14,797,300 m2), palustrine–emergent–persistent–temporarily flooded– Mixosaline (P-EPSX-) (296,600 m2), lacustrine–littoral–emergent–persistent–seasonally flooded–mixosaline– (LLEPSX) (2,079,900 m2), and lacustrine–littoral–emergent–persistent–Semipermanently flooded–mixosaline– (LLEPLX-) (493,000 m2). The results of this research in recognizing habitats are useful for the protection of ecosystem sections, especially plant communities

Calibration of SEBAL Surface Energy Balance Algorithm in Determining Evapotranspiration of Plains Affected by Flood Spreading (Qaracherian-Zanjan Province)

Evapotranspiration is one of the most important elements of the hydrological cycle. Estimation of evapotranspiration is imperative for effective forest, irrigation, rangeland and water resources management as well as to increase yields and for better crop management. The aim of this study is to calibrate the SEBAL algorithm in estimating evapotranspiration in the Sohrin-Qaracheryan plain, which is affected by flood spreading. In this study, Landsat 8 satellite images were used in 2020-2021 to obtain the coefficients of the relevant bands. Then, the net radiation flux on the earth’s surface and the earth’s heat flux is obtained using incoming-outgoing radiation fluxes from albedo, surface emissivity, land surface temperature, and plant indicators. Next, the sensible heat flux is calculated by determining the hot and cold pixels. Finally, evapotranspiration maps are plotted. Based on the results of this research evapotranspiration obtained from soil water balance model and SEBAL algorithm were estimated as 24115 and 19642 m3, respectively. Also, the calibration of the results obtained from the SEBAL algorithm with reference evapotranspiration was done using R2 and RMSE statistical indices, and were calculated the values of these two indices as 0.64 and 2.15, respectively

Effects of edaphic and geomorphologic factors on the performance of planted conifers and broadleaves at the Kamfirooz station, Fars province

Effect of edaphic and geomorphologic factors on the growth promotion or restriction of the planted seedlings of Cupressus sempervirens var. horizontalis Mill., Cupressus sempervirens var. arizonica Greene., Pinus brutia Elwes Henry., Pinus eldarica Medw., Ailanthus glandulosa Desff., Robinia pesudoacacia L., Quercus brantii var. persica Zohary., Fraxinus rotundifolia Mill. and Elaeagnus angustifolia L. was studied in a pilot project at the Kamfirooz research station in Fars province. The statistical design was completely randomized block with 3 replications. As in a previous 10-years study in the same area with the same species, significant differences had been observed among replications, we designed this problem oriented study to pinpoint the edaphic and geomorphologic factors, which might have influenced the performance of these species. Soil map units (SMU) were differentiated on the basis of topographical and geomorphological aspects. In each SMU, morphological characteristics of soil profiles (depth to the lithic contact) were studied, and three units A, B and C wee separated. Subunits were selected on the basis of factors that prohibit or improve plant growth. It was hypothesized that the presence or absence and the degree of cementation of marl stratum in the subsoil, and the degree of slope and amount of stones in the rooting zone, were the growth limiting factors. Moreover, soil physical and chemical characteristics were considered as the effective growth-modifying factors. The growth was evaluated visually and numerically from 1 (the best) to 5 (the worst). Also the 4 years average of survival rates in each replication were used to evaluated the relationship between plant growths and soil factors. We strongly believe that the morphology followed in our study is superior to the currently used evaluation techniques, as it takes into account those factors which heavily affect plant growth in our area

Impact of environmental factors on distribution of wild pear (Pyrus glabra Boiss.) in Sepidan region, Fars province

In this research, several ecological characteristics of Pyrus glabra Boiss. were studied. Distribution area of wild pear was drawn on a topographic map, and altitudinal range of horizontal and vertical distribution was determined. This species is mostly distributed on altitudes above 2000 m. Thirteen sample plots, each 1000 m2 were selected considering aspect, land form and altitudinal classes. In each sample plot, various variables such as species, diameter at breast height, tree height, crown cover, origin (standard or coppice), age class, number of sprouts, associated species and forest type were measured or recorded. A soil profile was dug in each sample plot in order to study physico–chemical properties of soil. Data were tested with Principal Component Analysis (PCA). The average number of trees per plot was 8, from which 73 percent were of coppice origin. The mean diameter of breast height was 14 cm and the average of tree crown area was 11 m2. The minimum and maximum height of trees were 2 m and 7.8 m, respectively, while the mean height was 4.6 m. The western aspects contained the highest number of trees per plot, while the eastern vallies showed the highest values for diameter at breast height, trunk height, crown area, and total height. The depth of bed rock and the percent of sand and gravel were limiting factors in the soil of the studied area. The soil fertility is sufficient for plant growth in most cases and could be regarded as moderate fertile forest soils. Land form and soil fertility are the most important factors for distribution of wild pear in the studied area

Impact of environmental factors on distribution and some quantitative characteristics of Manna Oak (Quercus brantii Lindl.) in Fars province

Tree species distribution in different ecological zones depends on their ecological demands including the physical and chemical properties of soils as well as different aspects and altitudes. In this research, several ecological characteristics of Quercus brantii were studied. This species is distributed in three altitudes of:1000-1500,1500-2000 and higher than 2000 m.a.s.l. Fifty two site samples, each covering 500m2, were selected in the basis of several parameters including aspect, land form and elevation classes. Different variables such as species, diameter at breast height (dbh), tree height, trunk height, crown cover, origin (standard or coppice), age class, number of sprouts, accompanying species and forest type were measured or recorded in each sample plot. Moreover, a soil profile was dug in each sample plot. Results showed that natural distribution of Quercus brantii varies from 1050 to 2550 m.a.s.l in all land forms. The pH of the studied sites varied between 7.5 and 8.1, and the soil texture varied from clay, clay- loam to loam. The most important limiting factors in the soil of the studied area were the texture and organic matter, whereas the soil moisture was an important factor for the presence of this species. The eastern slopes had the highest density, while the flat area showed the highest crown cover and dbh. The average crown area of each tree in seed origin and coppice origin plots were 16.61 m2 and 15.71m2, respectively. The mean dbh was 20.2cm and the average number of sprouts per tree was 5.9. The mean total tree height was 6.1m in seed origin and 5.59m in the coppice origin plots

Enhancing modelled water content by dielectric permittivity in stony soils

Applicability of time domain reflectometry (TDR) under naturally distributed stone fragments in soils has seldom been investigated. A multilayer profile of a 30-m-deep well was sampled and the natural distribution of stone fragments in the soils was replicated in the laboratory. Gravimetric soil water content (SWC) was measured simultaneously with TDR dielectric permittivity (Ka) readings and bulk densities in three subsamples as replications. Two connector and buriable probes and three reflection-time capture windows (10, 20 and 40 ns) were used for the measurements. These were repeated for sieved soil samples <2mm with fixed, pre-measured bulk densities. Measurements of Ka and observed SWC were repeated for extension-cable lengths of 3–30 m. All measurements were taken in samples saturated from the bottom. A semi-empirical mixture model was applied for different fractions of stony samples in order to convert bulk Ka to bulk volumetric SWC (qv) by the mixture model (qvmx), to be compared with qv by the conventional Topp equation (qvTp). An improvement in model performance was observed with lower root-mean-square error (RMSE, 0.02–0.04 v. 0.07–0.1) and ratio of RMSE to observation standard deviation (0.32–0.87 v. 1.07–3.05) for qvmx compared with qvTp. This approach for converting the in-situ measured dielectric permittivity to the qv of the bulk soil can be applied based on the determined stoniness. The 15-cm, 2-rod (connector) probe type with capture windows 20 ns resulted in a better performance than the 20-cm, 3-rod (buriable) probe type with capture windows 10 and 40 ns. Development of regression equations for the stonefree samples resulted in calibrated equations for converting the measured Ka to qv with better results (RMSE ~0.002m3 m–3) than those obtained using the Topp equation. In contrast to the traditional equation, new sets of coefficients for the Topp equation were also capable of estimating extremely low qv values of <=0.02m3 m–3 where the minimum calculated qv values were adequately similar to the observed ones. Noticeable effects of cable length on measured Ka were found for lengths exceeding 10 m. Accurate Ka values might be obtained in similar soil conditions if the suggested regression equations are employed, provided a correction is made for the extension cables

Statistical study of physiographic conditions in wild pistachio habitats using GIS in Fars province

Wild pistachio species, Pistacia atlantica and P. khinjuk, are xerophyte species in Irano-Toranian region, which are scattered in an area about 3200000 ha in four main open forest types of Fars province including: 1) Acer monpessulanum-Pistacia atlantica, 2) Amygdales spp.-Pistacia spp., 3) Pistacia spp. and 4) Quercus brantii-Pistacia atlantica. Regarding the distribution area, elevation, slope and aspect characteristics of wild pistachio, different maps were produced in 1:250000 scale using GIS. The distribution map of wild pistachio was integrated with the other mentioned maps. Analyze of variance and F- test showed that, 57% of habitats of wild pistachio species are mostly distributed between 1000 and 2000 m.a.s.l, 25.5% between 15% and 30% slope gradient and 66% of habitats in southern and northern aspects

Incorporating legacy soil data to minimize errors in salinity change detection: a case study of Darab Plain, Iran

The results of a 1990 soil survey of a salinized region in Darab Plain, southern Iran, were combined with soil sampling data taken in 2002 from the same locations and employed as a basis for salinity change detection in the region. New preprocessing of satellite imagery was used, along with statistical analysis of the digital number (DN)−salinity relationship, in order to determine salinization of the area. Removal of outliers on the basis of interfering land uses improved the correlations. Nonlinear regression (NLR) in the form y = a + bxα provided a suitable predictor of salinity (y, dS m−1) for both 1990 and 2002 based on DNs (x). Among the 12 tested methods of salinity classification in this study, the six salinity class method with intervals 0–4, 4–10, 10–32, 32–64, 64–80 and >80 dSm–1 was selected. A series of accuracy assessments through a trial-and-error procedure was the basis of the selection of the best method and led to a final accuracy of 91%. About 42% of the lands located on ‘no saline’ and ‘low salinity’ classes in 1990 had changed to the ‘medium’, ‘very high’ and ‘new agricultural land’ classes in 2002

Remote sensing estimation of actual evapotranspiration and crop coefficients for a multiple land use arid landscape of southern Iran with limited available data

The Gareh Bygone Plain is an arid area, south of Zagros Mountains, in Southern Iran, where a floodwater spreading project has been implemented for artificial recharge of groundwater. Knowledge/mapping of actual evapotranspiration for the mainland uses (natural pasture, irrigated crops and tree plantations) is of major importance for water management in this remote area. The Surface Energy Balance System (SEBS) model was used to estimate actual evapotranspiration (ET) using non-cloudy images for 32 dates of Landsat 5 TM from May 2009 to October 2010. Various improvements were required for ET computations, including relative to the very high wind speed observed. Reference ET was computed with observed weather data and SEBS products. Thus, crop coefficients (Kc) were obtained as the ratios of actual to reference ET relative to the main types of vegetation. The mid-season Kc generated with SEBS were compared with those previously obtained in the region and with those published in literature. Consumed water by cultivated crops based on SEBS compared well with applied water measurements. Coherent results were obtained which allow validating the SEBS approach for conditions of limited available data