Azam Karimi; Ataollah Ebrahimi; Esmaeil Asadi borojeni; Pejman Tahmasebi; Rahman Tavakoli
Abstract
One of the important factors threatening forests and rangeland is fires that leads to destruction of a large part of forests and rangelands. Study of this phenomenon and providing management strategies plays a major role to deal with and control such crisis. This study aimed to identify the affecting ...
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One of the important factors threatening forests and rangeland is fires that leads to destruction of a large part of forests and rangelands. Study of this phenomenon and providing management strategies plays a major role to deal with and control such crisis. This study aimed to identify the affecting factors of fire occurrence. The identification of major criteria conducted using a questionnaire as well as gathering information from Natural Resources and Watershed Management Organization in addition to calculation some others. To do so, 3 category of variables including 1- Human factors, 2- Biophysical factors and 3- Instrumental and logistic factors that contained altogether 26 variables are studied. In this research, Geographically Weighted Regression (GWR) method was used for mapping and zonation of the burned areas in the province that were occurred from 2007 to 2013. Results showed that amongst the 26 studied variables, monthly income (R=-0.61 and VIF=8.08) and number of rangeland and forest guardian members (R=-.56 and VIF=10.81), number of guard stations (R=-0.54 and VIF=2.2), guardsmen’s’ average age (R=0.53 and VIF=9.71 ), average of slope (R=0.5 and VIF=8.99) and number of voluntary rangeland and forest guards (R=-0.42 and VIF=15.11) are respectively the most affective variables on the occurred fires in range and forestlands. Finally, based on extracted predicted map Vardenjan, Mizdej-olia, Poshtkouh Ardal, and Aarmand are the most vulnerable counties for fire incident. Whilst, Monj and Mougooei encountered the least vulnerability of number of fire occurrence that is significantly in line with occurred fires.
Ahmad Ghanbari; Rafat Zare Bidaki; Afshin Honarbakhsh; Vafa Mahmoodinejad
Abstract
Check dam is the most costly watershed management practice. This research was an attempt to evaluate the effectiveness of individual check dams in different watersheds of Chaharmahal-va-Bakhtiari. 11 criteria impacting upon check dams’ individual efficiency were considered: check dam location, ...
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Check dam is the most costly watershed management practice. This research was an attempt to evaluate the effectiveness of individual check dams in different watersheds of Chaharmahal-va-Bakhtiari. 11 criteria impacting upon check dams’ individual efficiency were considered: check dam location, check dam stability, longitudinal profile fixing, check dam's coefficient of sediment storage, check dam's crest to be perpendicular to channel's axis, spillway dimensions, check dam strength, anchorage, check dams built according to channels' cross section, consistency of spillway center with stream alignment and apron length. The importance of each criterion for each check dam’s efficiency was measured using analytical hierarchy processes. 41 cement- masonry and gabion check dams constructed previously in different parts of the province were selected and were scored based on these criteria. Then by multiplying the weight of each criterion by the score each check dam received on that criterion, the distance of performance of each check dam from expected efficiency was computed. Results show that check dam's crest perpendicular to stream axis and consistency of spillway center with stream alignment averagely gained the highest score but longitudinal stream fixing and correct spillway dimensions gained the lowest score. And the location of check dams with the weight of 0.214 and apron length with the weight of 0.035 gained the highest and lowest weights, respectively. Economic assessment of check dams were done by comparing their final score in efficiency and the size of material used for that. It was revealed that small check dams constructed by consideration of designing principles showed more efficient and cost effective than huge check dams.
