Vol. 28 Issue 1
Ziad. Mimi, Nidal Mahmoud, and Maher Abu Madi
Groundwater in karstic aquifers can be dangerously sensitive to contamination. In this
paper, the DRASTIC model was modified and applied to address the intrinsic vulnerability of karst
aquifers. The theoretical weights of two DRASTIC’s parameters (aquifer media and hydraulic
conductivity) were modified through sensitivity analysis. Two tests of sensitivity analyses were
carried out: the map removal and the single parameter sensitivity analyses. The modified model was
applied to the karst aquifers underlying Ramallah District, Palestine, as a case study. The aquifer
vulnerability map indicated that the case study area is under low, moderate and high vulnerability of
groundwater to surface contamination. The vulnerability index can assist in the implementation of
groundwater management strategies to prevent degradation of groundwater quality. The modified
DRASTIC model has proven to be effective because it is relatively straightforward, using data that
is commonly available or estimated and produces an end product that is easily interpreted.
Adnan Enshassi, Said El-Moghany, Peter E. Mayer and Josef Zimmermann
Waste has been recognized as a major problem in the construction industry in developed
and developing countries. It has a considerable impact on the efficiency of the construction industry
and the overall economy of the country. Waste in construction is not only focused on the quantity
of material waste in construction, but also related to time waste. The aim of this paper is to identify
causes of time waste in construction projects and to rank these factors according to their importance
from contractors’ viewpoint in the Gaza Strip. The research approach adopted in this study was
questionnaire survey. 80 valid questionnaires have been studied and analyzed. The results of
analyzing 92 causes of time waste considered in this survey indicated that: rework that don’t comply
with drawings and specifications; lack of materials availability; rework due to workers’ mistakes;
effects of political and social conditions; and owner’s poor communication with the construction
parties and government authorities are the most five significant sources of time waste during the
construction process. The survey revealed that the site supervisor group is the major cause of time
delay. It would be appropriate to arrange formal and informal education and training in time waste
management for all concerned parties in the construction industry.
Mona Radwan
A physico-chemical water quality model has been developed and tested for the Rosetta
Branch in the Nile Delta. Water quality models are tools for analysing, extrapolating and predicting
the concentrations of dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen in the
form of ammonium (NH4-N) and nitrate (NO3-N), temperature (T) and total dissolved solids (TDS),
taking into consideration advection, dispersion and the most important biological, chemical and
physical processes. In this paper, the results of that model have been examined statistically based
on the time series of hourly values of water quality parameters and discharges at km 125 along
the Rosetta Brach. Relationships have been investigated between the water quality concentrations
and loads and the river discharges. Theoretical distributions have been searched which best fit the
time series for the different water quality parameters. They are applied to calculate exceedence
probabilities for the thresholds involved in recommended water quality standards. The study
concludes that, for DO, NO3-N and TDS parameters, average concentration values are within the
recommended standard by law 481982/ (Egyptian standard). Moreover, the average concentration
values for BOD and NH4-N violate the recommended standard. Also, the probability of exceedance
of the recommended standard for BOD, NO3-N, NH4-N, DO and TDS concentrations are 72%,
15%, 99%, 9% and 19% respectively. Correlation analysis indicated that strong load-discharge
relationships exist. The highest correlation coefficients for the load-discharge relationships were
recorded for TDS and DO and the lowest correlation coefficient was recorded for NH4-N.
Hassan Sulaiman Ahmed Mahdi
Participatory rural appraisal was carried out for 120 Tihama Plain Beekeepers in Hodeidah
governorate during two periods in 2001 and 2007. The results showed that 81.14%, 79.74%, 67.55%,
64.21%, 48.42%, 30.53% and 26.93% of the beekeepers suffered from many pests including Little
Green Bee-Eater, Wax Moths, Bee wolf, Ants, Yellow Wasp, Varroa mite and Death’s-head Moth for
two periods respectively. In addition, other pests, with varying degrees, such as Bee Lice, Red Date
palm Hornet, Acarine disease (tracheal mite) and others were found in their regions. Most honeybee
pastures were suffered from neglect or illegal cutting for fuel and / or construction and some of
them were infected with many pests, such as Al-Solab weed, Loranthus sp. and termites on Cidir
trees (Zizyphus spina Christi) in the valley of the Zabid and Rema. It was found that Cidir, Al-
Salam (Acacia ehrenbergiana) and Al-Thobaih (Acacia mellifera) plants were the most important
honey bee pastures for the production of honey in the Tihama plain, and sorghum, millet, and Alalqah
(Dipterygium glaucum) for brood breading. The results also indicated that the rate of annual
knowledge development of beekeepers in Tihama Plain and its valleys in relation to honey bee pests and honey bee pastures was low (0.02 and 0.05), respectively, compared to 0.02 and 0.06 for each
beekeepers of the directorate of Malhan in Al-Mahwit governorate and directorates of Abs an Harath
in Hajjah governorate. This assessment found no effective agricultural extension in the region. The
proportion of beekeepers who did not receive practical recommendations from the Extension Services
about the protection and management of Honey bee pastures or honey bees was 94.74% and 93.33%
for the first and second periods, respectively. The results showed that there were some incorrect
apiculture practices such as throwing wax combs near the bee hives after extracting honey from them
(39.39%) or feeding them sheep and cows(42.98%), leaving no sufficient distance between the bee
hives and neglecting cleaning bee hives after the mortality of bees at the end of bee season. These
factors can increase the chance of infestation with pests directly or indirectly.
Mohammed S. Faisal, Abdulghani O. Ismaeel, and Nahla M. Ali
The study included two experiments. The first one was done in the laboratory to show
the effect of aquatic extracts of wheat residues Abu-Ghraib-3 with the concentrations 5% and 10%
in addition to the control treatment on two cultivars of wheat: Abu-Ghraib-3 and Aqsad-65. The
greenhouse experiment included the addition of 10 day decayed wheat residues , these residues were
used after good mixing with the pots soil with the ratio 2.5 and 5% W/W in addition to the control
which represent a soil without residues under three levels of moisture content 50 , 75 and 100% to
identify its effect on some physiological characteristics and yield of the two studied cultivars. The
result of the laboratory experiment indicated that the aquatic extracts of wheat residues reduced the
germination in both varieties. Moreover , the greenhouse experiment showed that the addition of
residues especially with the ratio 5% inhibited some important features such as relative water content, proline root diameter and grain yield. While the moisture levels increased the relative water content
roots diameter. It was very clear that cultivar Aqsad-65-was superior over Abu-Ghraib-3. On the
other hand, the interaction between soil moisture levels and concentrations of residues removed the
negative effect of wheat residues to soil.