Entity

Time filter

Source Type


Heydarian S.A.,Soil Conservation and Watershed Management Research Institute SCWMRI
Irrigation and Drainage | Year: 2013

Irrigation management transfer (IMT) has already been implemented in over 60 countries. The project has faced different challenges and achieved various results in each country. Use of global experience in implementing IMT projects is highly recommended. Considering that the success of IMT is affected by various parameters, the present study has been conducted with the aim of finding the key indicators and strategic issues on the local, national and global levels. For this purpose, the data from four studies already carried out by the author (and his colleagues) on the local (the Moghan and Qazvin irrigation networks in Iran) and national scale (Iran) as well as global research by the Food and Agricultural Organization (FAO) were used. Currently Iran is at the rudimentary stages of IMT, and the two selected pilot studies deal with distinctive social and organizational features, operation time, irrigation method, physical status, conducted method and duration of IMT. The method of the study is descriptive correlation and the sample society consists of farmers on the pilot level and experts on the national level. The results reveal that the indicator of 'clarity on roles, responsibilities and authority of public sectors' has a low score. Although the effects of neglecting the said indicator are clearly manifest on the local level, and global experience has already established the fact, the significance of this indicator is not greatly recognized on the national level because of the limited IMT experience and simplicity-minded strategies in Iran. Key factors such as 'pilots, study tours and information sharing significance', 'severe deterioration of infrastructure' and 'financial capacity of water users' associations (WUAs)', on the other hand, are more important on the national level. This study enabled the author to develop an initial strategic framework for better utilization of the related experience in the field of IMT. © 2013 John Wiley & Sons, Ltd. Source


Raziei T.,Soil Conservation and Watershed Management Research Institute SCWMRI | Raziei T.,University of Lisbon | Bordi I.,University of Rome La Sapienza | Pereira L.S.,University of Lisbon
Water Resources Management | Year: 2013

In the present paper, regional drought modes in Iran are identified applying the Principal Component Analysis (PCA) and Varimax rotation to the Standardized Precipitation Index (SPI) computed on different time scales. Data used include gridded monthly precipitation covering the period 1951-2007 retrieved from the Global Precipitation Climatology Centre (GPCC) archive with different spatial resolutions (2. 5, 1 and 0. 5° resolution). The objective of the study is twofold: (i) Investigate the stability of drought spatial modes as a function of the SPI time scales used for monitoring the different kinds of drought, (ii) Evaluate the impact of the spatial resolution of gridded data on drought regionalization. For the coarse spatial resolution of 2. 5°, results show four drought modes of distinct variability, which remain quite stable when the SPI time scale is varied from 1- to 24-month. Differently, for higher spatial resolutions drought modes appear more sensitive to the index time scale and become less spatially homogeneous as the time scale is increased. Moreover, the number of identified modes (sub-regions) may reduce to three or two, but in all cases the most well defined sub-region appears to be the southern one. This suggests that both the spatial resolution of precipitation data and the time scale may affect drought regionalization, i. e. the number of drought modes and their spatial homogeneity. © 2012 Springer Science+Business Media B.V. Source


Raziei T.,Soil Conservation and Watershed Management Research Institute SCWMRI | Mofidi A.,Ferdowsi University of Mashhad | Santos J.A.,Royal University | Bordi I.,University of Rome La Sapienza
International Journal of Climatology | Year: 2012

The relationships between large-scale atmospheric circulation types and seasonal regimes of daily precipitation over Iran are assessed using daily precipitation from a high-resolution gridded dataset provided by the Asian Precipitation-Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources (APHRODITE) Project. Regional spatial modes of daily precipitation variability were identified by S-mode Principal Component Analysis (PCA) with Varimax rotation, applied to the subset of days when at least 10% of all grid-points over Iran received precipitation ≥ 5 mm. The study refers to the period 1961-2004 and is carried out for each season (excluding summer) separately. To characterize the dynamical features associated with each regional precipitation regime (PR), composites of daily atmospheric fields are computed by only averaging days with rotated PCA scores ≥ 1.5 (strong positive phase). In autumn and winter, Iran is divided into five PRs, while four PRs are identified in spring. Results suggest that the spatial distribution of precipitation over Iran is largely governed by the geographical position of both the mid-tropospheric trough over the Middle East and the Arabian anticyclone. In fact, in almost all PRs, the trough, as a pre-conditioning factor, leads to regional-scale ascending motions, whereas the Arabian anticyclone induces low-tropospheric moisture transports from southern water bodies into the cyclonic systems near Iran, triggering rain-generating conditions. © 2011 Royal Meteorological Society. Source


Raziei T.,Soil Conservation and Watershed Management Research Institute SCWMRI | Raziei T.,University of Lisbon | Daryabari J.,Islamic Azad University at Semnan | Bordi I.,University of Rome La Sapienza | Pereira L.S.,University of Lisbon
Theoretical and Applied Climatology | Year: 2014

Spatial patterns of monthly, seasonal and annual precipitation over Iran and the corresponding long-term trends for the period 1951-2009 are investigated using the Global Precipitation Climatology Centre gridded dataset. Results suggest that the spatial patterns of annual, winter and spring precipitation and the associated coefficients of variation reflect the role of orography and latitudinal extent between central-southern arid and semi-arid regions and northern and western mountainous areas. It is also shown that precipitation occurrence is almost regularly distributed within the year in northern areas while it is more concentrated in a few months in southern Iran. The spatial distribution of Mann-Kendal trend test (Z statistics) for annual precipitation showed downward trend in north-western and south-eastern Iran, whereas western, central and north-eastern exhibited upward trend, though not statistically significant in most regions. Results for winter and autumn revealed upward trend in most parts of the country, with the exception of north-western and south-eastern where a downward trend is observed; in spring and summer, a downward trend seems to prevail in most of Iran. However, for all seasons the areas where the detected trend is statistically significant are limited to a few spot regions. The overall results suggest that the precipitation is decreasing in spring and summer and increasing in autumn and winter in most of Iran, i.e. less precipitation during the warm season with a consequent intensification of seasonality and dryness of the country. However, since the detected trends are often not statistically significant, any stringent conclusion cannot be done on the future tendencies. © 2013 Springer-Verlag Wien. Source


Sharifi F.,Soil Conservation and Watershed Management Research Institute SCWMRI | Samadi S.Z.,University of Cardiff | Wilson C.A.M.E.,University of Cardiff
Natural Hazards | Year: 2012

In August 2001, the worst flash flooding event of the Caspian Sea regions in over two centuries claimed over 300 lives after a weekend of heavy rainfall and brought about a devastating disaster in the Mother-Soo catchment, province of Golestan, Iran. As a result of this event, a series of site investigation were carried out to identify the pertinent factors that led to a flood of this magnitude. This paper identifies the fundamental causes of the frequent floods and debris flow occurrence in the area prone to flooding and analyzes the main runoff mechanism of these events. The maximum observed 24-h rainfall depths and maximum peak discharges at the existing gauges were compared with the depths of rainfall and the peak values corresponding to the August 2001 flood respectively. For the majority of the rain gauges, the rainfall depth exceeded those of historical recorded events. In Golestan dam, an increase of 7. 5 times the maximum value observed in the past 20 years was noted. The flood height was 10-15 m while passing through the middle subcatchment area of Golestan National Park. The preliminary evaluation indicates the existence of bare soil in the catchment, movable material, steep slopes, high rainfall intensity, deterioration of pasture and forest land, and inappropriate agriculture and development practices as well as climate change were the main factors for the occurrence and the extent of the August 2001 disaster. Finally, due to the likelihood of flooding and debris flow events in future, some countermeasures are proposed. © 2011 Springer Science+Business Media B.V. Source

Discover hidden collaborations