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De Vente J.,CSIC - Center of Edafology and Applied Biology of the Segura | De Vente J.,CSIC - Estación Experimental De Zonas Áridas | Vanmaercke M.,Research Foundation Flanders FWO | Arabkhedri M.,Soil Conservation and Watershed Management Research Institute | Boix-Fayos C.,CSIC - Center of Edafology and Applied Biology of the Segura
Earth-Science Reviews | Year: 2013

Assessments of the implications of soil erosion require quantification of soil erosion rates (SE) and sediment yield (SSY) at regional scales under present and future climate and land use scenarios. A range of models is available to predict SE and SSY, but a critical evaluation of these models is lacking. Here, we evaluate 14 models based on 32 published studies and over 700 selected catchments. Evaluation criteria include: (1) prediction accuracy, (2) knowledge gain on dominant soil erosion processes, (3) data and calibration requirements, and (4) applicability in global change scenario studies. Results indicate that modelling of SE and SSY strongly depends on the spatial and temporal scales considered. In large catchments (>10,000km2), most accurate predictions of suspended sediment yield are obtained by nonlinear regression models like BQART, WBMsed, or Pelletier's model. For medium-sized catchments, best results are obtained by factorial scoring models like PSIAC, FSM and SSY Index, which also support identification of dominant erosion processes. Most other models (e.g., WATEM-SEDEM, AGNPS, LISEM, PESERA, and SWAT) represent only a selection of erosion and sediment transport processes. Consequently, these models only provide reliable results where the considered processes are indeed dominant. Identification of sediment sources and sinks requires spatially distributed models, which, on average, have lower model accuracy and require more input data and calibration efforts than spatially lumped models. Of these models, most accurate predictions with least data requirements were provided by SPADS and WATEM-SEDEM. Priorities for model development include: (1) simulation of point sources of sediment, (2) balancing model complexity and the quality of input data, (3) simulation of the impact of soil and water conservation measures, and (4) incorporation of dynamic land use and climate scenarios. Prediction of the impact of global change on SE and SSY in medium sized catchments is one of the main challenges in future model development. No single model fulfils all modelling objectives; a further integration of field observations and different model concepts is needed to obtain better contemporary and future predictions of SE and SSY. © 2013 Elsevier B.V.

Rashidi Mehrabadi M.H.,Islamic Azad University at Tehran | Saghafian B.,Islamic Azad University at Tehran | Haghighi Fashi F.,Soil Conservation and Watershed Management Research Institute
Resources, Conservation and Recycling | Year: 2013

Global demand for clean water supplies is on the rise due to population growth. This is also true in most cities of Iran. Non-conventional water resources must be developed to partially offset the increasing demand. In this study, the applicability and performance of rainwater harvesting (RWH) systems to supply daily non-potable water were assessed. Storage of rain falling on the roofs of residential buildings and directed into installed tanks was simulated in three cities of varying climatic conditions, namely Tabriz (Mediterranean climate), Rasht (humid climate), and Kerman (arid climate). Daily rainfall statistics for a period of 53 years as well as the information on the contributing roof area, available tank volumes and non-potable water demand were collected in each city. Typical residential buildings with roof areas of 60, 120, 180 and 240 m2 with an average of four residents in each house were considered for the study. According to the results in humid climate, it is possible to supply at least 75% of non-potable water demand by storing rainwater from larger roof areas for a maximum duration of 70% of the times. For roofs with small surface area, the supply meets 75% of non-potable water demand for a maximum duration of 45% of the times. Moreover, for Mediterranean climate, it is possible to supply at least 75% of non-potable water demand in buildings with larger roof areas for a maximum duration of 40% of the times. It is also found that in arid climate, similar duration is only 23% of the times. © 2013 Elsevier B.V.

Raziei T.,Soil Conservation and Watershed Management Research Institute | Bordi I.,University of Rome La Sapienza | Pereira L.S.,University of Lisbon
Water Resources Management | Year: 2011

The lack of reliable and updated precipitation datasets is the most important limitation that hinders establishing a drought monitoring and early warning system in Iran. To overcome this obstacle, we have evaluated the applicability of GPCC and NCEP/NCAR precipitation datasets for drought analysis in Iran. For this purpose, drought variability across the country has been analyzed through the standardized precipitation index (SPI) on 12-month time scale based on the common period 1951-2005. For each dataset, by applying the principal component analysis (PCA) to the SPI field and Varimax rotation, the studied area has been regionalized into a few distinctive sub-regions characterized by independent climatic variability. Results have been checked against observations at 32 rain gauge stations having reliable data for the study period. Both GPCC and NCEP/NCAR datasets identify the same sub-regions of drought variability and they are in good agreement with observations. However, the NCEP rotated principal component scores associated with the sub-regions show different time variability with respect to the behaviours captured by GPCC, on one hand, and observations, on the other hand. It seems that, in central Iran such differences concern mainly the period before the seventies. Thus, the results suggest that GPCC dataset is a useful tool for drought monitoring in Iran and it can be used to complement the information provided by rain gauge observations. The NCEP/NCAR reanalysis dataset shows a better agreement with observations for the period 1970-2005 than for 1951-2005, and its discrepancies in the regional time variability of drought with respect to GPCC and observations should be taken into account when periods before the seventies are considered. © 2010 Springer Science+Business Media B.V.

Martins D.S.,University of Lisbon | Raziei T.,University of Lisbon | Raziei T.,Soil Conservation and Watershed Management Research Institute | Paulo A.A.,University of Lisbon | And 2 more authors.
Natural Hazards and Earth System Science | Year: 2012

The spatial variability of precipitation and drought are investigated for Portugal using monthly precipitation from 74 stations and minimum and maximum temperature from 27 stations, covering the common period of 1941-2006. Seasonal precipitation and the corresponding percentages in the year, as well as the precipitation concentration index (PCI), was computed for all 74 stations and then used as an input matrix for an R-mode principal component analysis to identify the precipitation patterns. The standardized precipitation index at 3 and 12 month time scales were computed for all stations, whereas the Palmer Drought Severity Index (PDSI) and the modified PDSI for Mediterranean conditions (MedPDSI) were computed for the stations with temperature data. The spatial patterns of drought over Portugal were identified by applying the S-mode principal component analysis coupled with varimax rotation to the drought indices matrices. The result revealed two distinct sub-regions in the country relative to both precipitation regimes and drought variability. The analysis of time variability of the PC scores of all drought indices allowed verifying that there is no linear trend indicating drought aggravation or decrease. In addition, the analysis shows that results for SPI-3, SPI-12, PDSI and MedPDSI are coherent among them. © 2012 Author(s).

Khaledi Darvishan A.,Tarbiat Modares University | Sadeghi S.H.,Tarbiat Modares University | Homaee M.,Tarbiat Modares University | Arabkhedri M.,Soil Conservation and Watershed Management Research Institute
Hydrological Processes | Year: 2014

The bulk of eroded soils measured at the outlets of plots, slopes and watersheds are suspended sediments, splash-induced sheet erosion. It is depending on rainfall intensity and antecedent soil moisture contents and contributes to a significant proportion of soil loss that usually is ignored in soil erosion and sediment studies. A digital image processing method for tracing and measuring non-suspended soil particles detached/transported by splash/runoff was therefore used in the present study. Accordingly, fine mineral pumice grains aggregated with white cement and coloured with yellow pigment powder, with the same size, shape and specific gravity as those of natural soil aggregates, called synthetic color-contrast aggregates, were used as tracers for detecting soil particle movement. Subsequently, the amount of non-suspended soil particles detached and moved downward the slope was inferred with the help of digital image processing techniques using MATLAB R2010B software (Mathworks, Natick, Massachusetts, USA). The present study was conducted under laboratory conditions with four simulated rainfall intensities between 30-90mmh-1, five antecedent soil moisture contents between 12-44 % vv-1 and a slope of 30%, using sandy loam soils taken from a summer rangeland in the Alborz Mountains, Northern Iran. A range of total transported soil between 90.34 and 1360.93gm-2 and net splash erosion between 36.82 and 295.78gm-2were observed. The results also showed the sediment redeposition ratio ranging from 87.27% [sediment delivery ratio (SDR)=12.73%] to 96.39% (SDR=3.61%) in various antecedent soil moisture contents of rainfall intensity of 30mmh-1 and from 80.55% (SDR=19.45%) to 89.42% (SDR=10.58%) in rainfall intensity of 90mmh-1. © 2013 John Wiley & Sons, Ltd.

Saghafian B.,Soil Conservation and Watershed Management Research Institute | Noroozpour S.,Shahid Chamran University
Journal of Hydrology | Year: 2010

Du et al. (2009) presented a time variant spatially distributed travel time method in order to simulate storm runoff response for a watershed in China. There are a number of issues raised in their paper that require further thoughts. One of the important issues is the assumption of travel time being dependent on the flow velocity rather than the wave celerity. Another problem deals with the introduction of a parameter (K) that accounts for the estimation error for roughness coefficient and bed slope. While the default K value must be unity, a value of 7.5 was calibrated. Other issues deals with ignoring the effect of flow accumulation in overland cells, calibration of a sensitive channel threshold parameter, trying to keep the mass conserved through the routing procedure while the isochrone locations vary in time, and the application of SCS infiltration method during the no-rain period. This commentary elaborates on the above issues. © 2009 Elsevier B.V. All rights reserved.

Mostafaei A.,Soil Conservation and Watershed Management Research Institute | Mostafaei A.,Shahid Chamran University
Environmental Management | Year: 2014

The Kashkan River (KR), located in the west of Iran, is a major source of water supply for residential and agricultural areas as well as livestock. The objective of this study was to assess the spatial and long temporal variations of surface water quality of the KR based on measured chemical ions. The Canadian Council of Ministers of Environment Water Quality Index (CCME WQI) technique was utilized using measurements from 10 sampling stations during a period of 36 years (1974-2009). The measured data included cations (Na+, K +, Ca2+, Mg2+), anions (HCO3 -, Cl-, SO4 2-), pH, and electrical conductivity. Principal component analysis was performed to identify which of the parameters to be included in the CCME WQI calculations were actually correlated and which ones were responsible for most of the variance observed in the water-quality data. In addition, KR water quality was evaluated for its suitability for drinking and irrigation purposes using conventional methods. Last, trend detection in the WQI time series of the KR showed water-quality degradation at all sampling stations, whereas the Jelhool sub-basin more adversely affects the quality of KR water in the watershed. Nonetheless, on average, the water quality of the KR was rated as fair. © 2014 Springer Science+Business Media.

Shoaei Z.,Soil Conservation and Watershed Management Research Institute
Environmental Earth Sciences | Year: 2014

Seimareh Landslide (SL) is globally recognized as one of the largest rock mass movements in the world. It is located along the border of Ilam and Lorestan provinces in southwest Iran, in the heart of the Zagros Mountain Range. There are controversial findings about the mechanism of the landslide formation. This field work study reviewed the possible mechanisms of failure and analyzed post-failure geomorphic features. Drainage pattern disturbance in the depositional region and consequent dammed lake formation are among the most significant characteristics of these features. Seimareh, Jaidar and Balmak are three large landslide-dammed lakes. The present study analyzed the processes responsible for the formation and erosion of the Jaidar and Seimareh Landslide dams using the available annual sedimentation and field measurements of the sediment deposited in these lakes. The results showed that the SL dam has been formed about 935 years after the landslide event. Detailed field investigations indicated a specific hydro-morphological condition in the landslide area. The results implied that the main causes of the failure were probably the particular hydro-morphological characteristic of the landslide source area together with the enormous eroding energy resulted from merging of two high-flow rivers which eroded the base of the southern flank of Kabir-kuh Mountain. However, the unusual size of the landslide suggests that an external factor, e.g., a huge earthquake, might have triggered the failure. © 2014, Springer-Verlag Berlin Heidelberg.

Gharibreza M.,Soil Conservation and Watershed Management Research Institute
Quaternary International | Year: 2015

The Coastal Makrn (CM) is the outermost part of the Makran zone, which is one of few intact areas to study the evolutionary trend of raised beaches and also to estimate the rate of coastal progradation since the late Holocene. The Makran zone is an accretionary wedge that has formed by the subduction of oceanic crust of Arabian Plate under the Eurasian Plate. The CM range in Iran is located between the eastern corner of the Hormuz Strait and the middle of the Guwader Bay at the Iran-Pakistan boundary. This research method utilized remote sensing (RS) techniques and geographic information system (GIS), field survey and radiocarbon dating of fossils The data indicate the effective limit of the Flandrian transgression (18,000BP) and paleo-geographical features in the mid-Holocene. Sequences and time periods of fossil beach development and the mean rate of shoreline mobility and uplift in omega-shaped bays were obtained. Coastal progradation from the oldest fossil beach in the Kerian area started from 4329±64Cal BP, and in Chabahar and Guwader Bay from 5438±87Cal BP and 5389±58Cal BP, respectively. Different rates of uplift result from tectonic movements of various scales. Development of fossil beaches in the Chabahar and Pozm Bays since the mid-Holocene coincided with a clear increase in rate of uplift from 0.71mmy-1 to 5.02mmy-1. The highest rate of uplift of fossil beaches (5.02mmy-1) occurred at Darango Bay. Tombolos were identified as a main paleo-geographic feature of the CM zone in the early Holocene. Such landforms were gradually converted to Omega-shaped bays from the mid-Holocene. Developments of Omega-shaped bays are continuously in progress by a regional mechanism, in which wave regimes and sediment supply from hinterlands are relatively stable. Paleo-geographic features of the area in the mid-Holocene were built based on land progradation rate, tectonic events, and trend of sea level changes. © 2015 Elsevier Ltd and INQUA.

Rahmanipour F.,Tarbiat Modares University | Marzaioli R.,The Second University of Naples | Bahrami H.A.,Tarbiat Modares University | Fereidouni Z.,Tarbiat Modares University | Bandarabadi S.R.,Soil Conservation and Watershed Management Research Institute
Ecological Indicators | Year: 2014

Soil quality evaluation is a tool to improve soil management and land use system. A large number of different physical, chemical and biological properties of soil, known as soil quality indicators, are used to soil quality assessment. These properties, that are sensitive to stress or disturbance, are synthesized using numerical quality indices obtained by several different types of methods. The aim of this study was to compare two different methods for soil quality index calculation in agricultural lands of Qazvin Province, Iran. In particular, the Integrated Quality Index (IQI) and Nemoro Quality Index (NQI) models were applied using the indicator selection methods: Total Data Set (TDS) and Minimum Data Set (MDS). Ten soil quality indicators were included in TDS: pH, Electrical Conductivity (EC), Organic Matter (OM), Cation Exchange Capacity (CEC), percentage of equivalent CaCO3 (TNV), heavy metal content of cadmium (Cd), cobalt (Co), lead (Pb), chromium (Cr) and soil erodibility factor (K), while Principal Components Analysis (PCA) was used to select the indicators to include in MDS. The tested soil quality indices were appropriate to evaluate the effects of land management practices on soil quality. The results of the linear relationship as well as of the match analysis, among the approaches studied, identified better estimation of soil quality applying IQI index when compared to NQI index and higher values of agreement of TSD than MSD. However, also IQIMSD approach resulted in suitable evaluation of the effects of land management practices on soil quality. This latter result was particularly relevant in the area studied because the use of a limited number of indicators could allow to reduce the cost of the analysis and to increase the sampling density in order to obtain a more detailed evaluation of soil quality through a geostatistical approach. © 2013 Elsevier Ltd. All rights reserved.

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