Journal of King Abdulaziz University: Meteorology, Environment and Arid Land Agriculture

Stability Evaluation of Rabigh Concrete Gravity Dam

Abdullah Alzahrani — 2024-10-15

Concrete dams are constructed for holding big volume of water for various uses. In terms of economic and social development, they viewed it as a critical component of the country's infrastructure for flood control, hydropower generation and water transportation, irrigation, and water delivery. Stability is usually a major issue in the dam of gravity dams, and if there are any weak structural planes in the dam that might cause failure (Ghanizadeh and Ghanizadeh, 2017).

Rabigh dam (RD) is the third important dam in Saudi Arabi, located in the eastern side of the Red Sea. It was built in 1987 and intended to protect Rabigh industrial city and recharging the groundwater. RD is a concrete gravity type, 81 m high with a huge reservoir of 229 million m³. The reservoir has a permanent dead water load at a level of 63 m (minimum water level), and discharges flood water through a sufficient spillway at an elevation of 71 m (maximum water level).

The main objective of this study is to reevaluate the dam stability. Gravity dams, in general, are subjected to two hydraulic forces (the lateral water force, Fw and the uplift, U) in addition to sedimentation (Sd) and their stability relies on its self-weight (Wt.). Several recent research warned of an expected increase of rainwater and flood frequency due to global warming, which will raise the destabilizing forces while the dam weight (Wt.) is constant. RD possible movement during its normal operation was checked in two conditions: dam overturning and sliding. The possibility of dam overturning was tested at two water levels behind the dam; at 63 (the dead load level) and 71.5 m (the spillway level), the resulting factor of safety (F_s) are 1.85 and 1.50 respectively. The stability against dam sliding was evaluated at the same water levels giving a save F_s-value of 1.51 at the lower level and 1.23 at the higher one. On the other hand, the acting forces introduce compressive and tensile stresses on dam body of 188.9 t/m² and 12 t/m², respectively. The internal stresses which may develop in the dam body is much less than the allowable limits.

Potent Plant Extracts: Combatting Potato Tuber Soft Rot Disease Caused by Pectobacterium carotovorum subsp. carotovorum

Najeeb almasoudi — 2024-10-15

The objective of this research was to assess the efficacy of three plant extracts—Cumin, pomegranate, and Black pepper against Pectobacterium carotovorum subsp. carotovorum, a bacterium responsible for causing soft rot disease in potato tubers. This ailment poses a significant threat to potato production, impacting the quality of potatoes throughout storage, transit, and shipment. To conduct the investigation, twenty isolates of the pathogenic bacterium were acquired from naturally infected potato tubers and identified as P. carotovorum subsp. carotovorum through various microbiological characteristics. Through in vitro experiments, the plant extracts were examined for their antibacterial properties against the bacterium. The findings revealed that all three plants extract exhibited inhibition of bacterial growth. Notably, pomegranate demonstrated the most potent inhibitory effect among the three extracts. In light of these in vitro results, it is recommended to employ all extracts at a concentration of 50 mg to effectively control soft rot disease in potato tubers during storage. The concentration of 50 mg was identified as the most effective in impeding the growth of the pathogenic bacterium. In summary, this study demonstrated the potential of all tested plant extracts to mitigate potato tuber soft rot disease, addressing a significant challenge in potato production.

Effect of Salinity Stress, Humic Acid and Nanochitosan on plant

IBTISAM ALGHABBAN — 2024-10-15

Abstract Salinity reduces the agricultural productivity of most plants. Humic acid (HA) and chitosan nanoparticles (CNPs) offer promising benefits for sustainable agricultural production due to their natural origins and potential to be used as a treatment for the effects of salt stress, improving plant resilience and productivity so that we can avoid salt use. Water in agriculture. Or reduce the harmful effects of its use on plants, as stated in previous literature. The present review represents details about salt stress and the damages and negative effects it causes on plant growth, agricultural production, and metabolites within the plant. It also sheds light on the definition of humic acid and its composition, effective and positive role in plant growth and increasing resistance to salinity. It also clarified the importance played by nanocomposites (nano chitosan) and their role as treatments for salinity.

Impact of landfill fly ash on soil contamination with heavy metals in Rabigh Area, Saudi Arabia

Al-Solaimani Samir G. M. — 2024-10-15

This study was carried out to investigate special distribution of micro- and toxic-elements separated from carbon fly ash buried in landfill in Rabigh, Saudi Arabia. The highest total and DTPA extractable and available concentrations of sulfur (S), manganese (Mn), zinc (Zn), copper (Cu), iron (Fe), aluminum (AL), cobalt (CO), chromium (Cr), nickel (Ni) , vanadium (V) are in the soil inside the landfill, then concentrations decrease with increase in distances 0, 250, 500, 1000 m away from landfill at all locations, north south, east, west. The soil total micro-and toxic-element accumulations are highest at south location, followed by east, then west and the least concentrations are in the soil of the north location. The soil DTPA extractable available micro- and toxic-elements are highest at the east location, then south then north and west location has soil with the least element concentrations. Iron (Fe) as soil total micro-element is the highest (38888.37 mg/kg), but as DTPA available element it is very low (16.46 mg/kg) at all locations and distances. Sulfur (S) comes second to Fe as total soil element with (541.24 mg/kg), then Mn element, while for soil DTPA available micro-elements S is the highest element (193.60 mg/kg) followed by Fe, and Cu is the element with the least concentrations in the soil. For toxic-elements Al dominates total soil concentrations (19173.27 mg/kg), followed by V then Cr, Ni and Co, and for DTPA available soil metals Ni and V gave higher concentrations than Co and Cr at all distances and locations. The concentration of soil total Fe is higher than European Standards (2002) , Saudi Standards ( 2020 ) and Indian Standards (2000), and that of S is higher than Saudi Standards (2020). Nickel (Ni) is higher than Saudi Standards (2020). The rest metal concentrations in landfill soil are below phototoxic concentration standards put forward by EU (2002), Saudi Arabia (2020), and Indian standards (2000). The rest element concentrations in landfill soil are below phototoxic concentration standards put forward by these standards.

Studies of freshwater cyanobacteria strains from an ecological perspective in the western region of Saudi Arabia

Esmat F Ali — 2024-10-15

A class of photo-oxygenic bacteria known as cyanobacteria, or blue green algae, can be found from pole to pole in aquatic, aerophytic, and terrestrial environments. They are some of the most common species on Earth and belong to one of the oldest prokaryotic lineages. Only a little amount of research on cyanobacterial strains was conducted in the central and southern regions. This cyanobacteria cological study is thought to be the first in the Kingdom of Saudi Arabia's western region. From this vantage point, the identification of cyanobacteria strains, their physical and chemical characteristics, and the impact of salinity in this area will take precedence. There are two primary components to the current research. The isolated strains were defined and isolated in the first section. The physical and chemical properties are examined in the second section.