Reservoir volume optimization and performance evaluation of rooftop catchment systems in arid regions: A case study of Birjand, Iran

This study evaluated the performance of rooftop catchment systems in securing non-potable water supply in Birjand, located in an arid area in southeastern Iran. The rooftop catchment systems at seven study sites of different residential buildings were simulated for dry, normal, and wet water years, using 31-year rainfall records. The trial and error approach and mass diagram method were employed to optimize the volume of reservoirs in five different operation scenarios. Results showed that, during the dry water year from 2000 to 2001, for reservoirs with volumes of 200-20000 L, the proportion of days that could be secured for non-portable water supply was on average computed to be 16.4%-32.6% across all study sites. During the normal water year from 2009 to 2010 and the wet water year from 1995 to 1996, for reservoirs with volumes of 200-20000 L, the proportions were 20.8%-69.6% and 26.8%-80.3%, respectively. Therefore, a rooftop catchment system showed a high potential to meet a significant portion of non-potable water demand in the Birjand climatic region. Reservoir volume optimization using the mass diagram method produced results consistent with those obtained with the trial and error approach, except at sites #1, #2, and #5. At these sites, the trial and error approach performed better than the mass diagram method due to relatively high water consumption. It is concluded that the rooftop catchment system is applicable under the same climatic conditions as the study area, and it can be used as a drought mitigation strategy as well.

Analysis of Rooftop Rainwater Harvesting in Kabul New City: A Case Study for Family Houses and Educational Facilities

The Afghan government has planned the project of Kabul New City (KNC) to cope with the rapid growth of Kabul, an existing capital city. Due to climatic and topographical reasons, it is supposed that KNC suffers from a water scarcity problem. This study investigates the feasibility of a rooftop rainwater harvesting system in KNC to relieve the water scarcity problem. An applicability of the rooftop rainwater harvesting system was discussed for several types of residential houses and schools, using 11 years rainfall data. This study also examined the cost-effectiveness of the system by considering the service life of the system. Furthermore, an optimal size of the rainwater storage tank was discussed based on the balance among harvested rainwater volume, non-potable water demand, and cost-effectiveness.

Remedial ability of maize(Zea-Mays)on lead contamination under potted condition and non-potted field soil condition

This study presents the remedial ability of maize on lead(Pb)contaminated soil.Soil samples were collected randomly from the site and subjected to physico-chemical tests before experimen-tation.The samples were contaminated artificially at six different concentration levels of lead nitrate(Pb(NO_(3))_(2)).Experimental design was 4-factorial combination(6×6×2×1).The study duration was 10 weeks,and during this period,Pb contents of the soil were analyzed in intervals of two weeks.Analyzed physico-chemical properties of the soil showed that the soil was loamy with pH 6.82,electrical conductivity 1.62 dS/m and adequate macro nutrient elements.The av-erage percentage removal of Pb from the soil was 2.25%and 3.67%for potted and non-potted experiments,respectively.Similarly,the average percentage of Pb in the roots was 1.10%and 1.68%for potted and non-potted experiments,respectively.The result of this study indicated that extraction of Pb by the plant system increased with the increase of lead concentration in the soil as well as in the extent of vegetation attained by the crop.It also clearly showed that the non-potted experiments demonstrated greater influence on removal of Pb from the soil system than the potted experiments.