The shortage of water is a major obstruction to the social and economic development of many countries, including Egypt. Therefore, there is an urgent need to properly manage water resources to achieve optimum water use. One way of saving available water resources is to reduce evaporation that leads to the loss of a large amount of water from reservoirs and open lakes. This paper aims to use a floating photovoltaic system (FPVS) to cover a lake’s water surface to reduce evaporation and also for energy production. This methodology was applied to Lake Nasser as one of the largest lakes in the world where much evaporation happens due to its large area, arid environments, and the shallow depths of some parts of the lake. The estimated evaporation from the lake was 12.0 × 10⁹ m³/year. The results show that covering 25%, 50%, 75%, and 100% of the lake can save about 2.1, 4.2, 6.3, 7.0, and 8.4 × 10⁹ m³/year and produce energy of 2.85 × 10⁹, 5.67 × 10⁹, 8.54 × 10⁹, and 11.38 × 10⁹ MWh/year, respectively. Covering areas of shallow water depth was more efficient and economical. The results show that covering 15% of the lake’s area (depths from 0.0 to 3.0 m) can save 2.66 × 10⁹ m³/year and produce 1.7 MWh/year. Covering 25% of the lake’s area (depths from 0.0 to 7.0) can save 3.5 × 10⁹ m³/year and produce 2.854 MWh/year. Using an FPVS to cover parts of Lake Nasser could help manage water resources and energy production for Egypt to overcome the likely shortage of water resources due to population growth. This system could be applied in different locations of the world which could help in increasing water resources and energy production, especially in arid and semi-arid regions.

Urban growth is one of the major causes of flooding in urban areas. This affects the runoff coefficients, which is among the most important factors that affect the design of storm water drainage systems. Changing the runoff coefficient will affect the design parameters of the drainage network, including outfall discharge, velocity, lag time and cost of construction. This study aims to assess the effect of changing the runoff coefficient due to urban growth on the design of a storm water drainage system. The hydrological models Hyfran, StormCAD and GIS are used to analyze different runoff coefficients. This study examines three zones in Dammam in the Kingdom of Saudi Arabia (KSA). The data developed from the models for the current case studies are used to develop an empirical equation to predict the max discharge for other catchments. The discharge is a function of the return period, runoff coefficient, drainage density, longest path, rainfall intensity and catchment area. To validate the developed equation, we use it to estimate the discharge in a real case study in South Korea. A comparison between the measured discharge and estimated discharge shows that the empirical equation is capable of predicting the maximum discharge for different catchments with high accuracy. Then, the validation of the models is carried out to determine the effect of the runoff coefficient on the design of a storm water drainage system in a case study in KSA. The results show that an increasing runoff coefficient due to urban growth increases the outfall discharge and velocity of storm water drainage systems, as well as affecting the cost of construction and decreasing the lag time. The cost increases by two to three times with increasing urbanization. This study provides a new perspective on the hydrologic impact of urban growth on the design of storm water drainage systems, which are essential for flood management. Moreover, the relationship between urban growth and the cost of storm drainage networks is explored, which could help decision makers to make appropriate judgements.

Debris accumulations upstream and through crossing hydraulic structures such as culverts cause the upstream water level and the downstream scour depth to increase, which can lead to structure failure. This experimental study aimed to investigate the effects of various inlet blockage ratios on culvert efficiency and scour hole depth. In a non-blocked case, various submergence ratios (S = 1.06, 1.33, 1.60, and 1.90) were tested with different discharge rates. In a blocked case, the effects of inlet blockage with various blockage ratios (Ar = 10%, 20%, and 30%) were seen as sediment blockage on the pipe bed or floating debris upstream of the culvert. The results show that as the submergence ratio increases, the maximum scour depth decreases at the same discharge rate, and the relative energy loss also decreases in the non-blocked case. In the sediment blockage (Ar d) case, the relative maximum depth increases with increasing densimetric Froude number and with an increasing blockage ratio. An empirical equation was developed to predict the relative scour depth under the present study conditions.

Water resources management in high-stress regions is a large-scale problem affecting food and water security. Therefore, modern irrigation systems such as sprinklers, subsurface, and drip irrigations are applied to manage the water shortage in regions of the Nile delta. Because of the increase in population rate and climate change, freshwater supplies are significantly limited and must be efficiently managed. Consequently, Egypt plans to implement MIS in the old land of the Nile delta. The current study aims to investigate and model the recharge from the excess irrigation system that affects groundwater storage and land subsidence unexpectedly. The visual modflow was applied to investigate the groundwater heads and drawdown. At the same time, the analytical solution based on Terzaghi theory, and the surfer software was used to estimate and map the land subsidence.For this reason, we investigated the groundwater drawdown in the high-water shortage of Egypt’s Nile delta. Three scenarios were considered by changing irrigation methods and their Impact on land subsidence in the Nile Delta Aquifer (NDA). Therefore, the results of this study demonstrated that the groundwater drawdown reached 2.60 m, 4.20 m, and 6.50 m, respectively. In contrast, the land subsidence outstretched 26 m, 44 m, and 65 cm for the sprinkle sub-surface. Future design infrastructures such as pipelines, roads, irrigation networks, canals, and water structures should consider land subsidence due to modern irrigation systems (MIS).

Storm water drainage system in urban areas became a deterministic system, especially in light of the current climate changes. This system eliminates the excess water resulting from heavy rainfall, which leads to disruption of daily life. Irregular maintenance of the network system, problems appear, especially the blockage of the covers or network pipes, which affects the efficiency of the network. This study deals with the experimental investigation of blockage on storm network system and the relationship between efficiency of the system and blockage parameters. Many scenarios of blockage within grate and pipe were studied and its impact on storm system efficiency calculated. For the pipe system, two scenarios were studied; the first one is the blockage of end main pipe with relative blockage height (15%, 30%, 50%, 70%, and 90%). The second one is the blockage through the main pipe with relative blockage height (25%, 50%) and relative blockage length (33%, 67%, and 100%). For grate, the blockage is investigated with the blockage area ratio (12.5%, 25%, 37.5%, and 50%). In addition, the combined blockage of grate and pipe was studied. Finally, an equation has been created to estimate the system efficiency as a function of blockage ratios and system discharges. The results indicated that for surface blockage (12.5%, 25%, 37.5%, and 50%), the discharge efficiency decreased as the amount of blockage increased with different grate blockage by (17.8%, 19.3%, 21%, and 24.6%), respectively.

Climate change could cause changes in temperature and precipitation patterns that may increase the probability of drought. Climate change could enormously affect arid regions, and many countries may suffer from drought. This study aims to monitor the historical drought in Syria. Monthly data was collected from 71 land stations for the period (1991–2009). After 2010, the field data were not available due to the civil war in Syria. The satellite images for monthly precipitation were collected for the period (1983–2020). Remote Sensing (RS) and Geographic Information System (GIS) were used to correct the satellite images using the land station data for the period (1991–2009), and a correction equation was developed for each station that was used to correct the data for the period (1983–2020). Drought risk analysis was carried out utilizing the Standardized Precipitation Index (SPI) in the period (1983–2020). Three main types of droughts have been detected: meteorological, agricultural and hydrological drought. The results showed that significant drought struck Syria, where, the long-term drought (hydrological) occurred in 1988–1989 and 2013–2014. From the assessment of months for the period 1983–2020 in Syria, it is obvious that the driest year was 2013, and extremely dry and very dry were repeated in the years 1988, 1993, 1999, 2003, 2008, 2013 and 2017. This reveals that the dry season is repeated between 4 and 6 years with an average of 5 years. The results of the SPI trend analysis showed increasing trends at all the stations. This highlights the impact of climate change on Syria, which may suffer from more droughts in the future, which in turn affect the availability of water resources. The results of this research could help to manage water resources and adapt to climate change risks in Syria. The results proved that SPI is a useful tool to monitor drought that could help decision-makers put efficient plans for drought risk management. Graphical Abstract The current study aims to monitor the historical drought in Syria using remote sensing data. Monthly data was collected from 71 land stations for the period (1991–2009). Then satellite images for monthly precipitation were collected for the period (1983–2020). RS and GIS were used to correct the satellite images using the land station data for the period (1991–2009), and a correction equation was developed for each station that was used to correct the data for the period (1983–2020). Drought risk analysis was carried out utilizing SPI in the period (1983–2020). Three main types of droughts have been detected: meteorological, agricultural and hydrological drought. The findings indicated that Syria experienced significant drought conditions, with the long-term drought index (SPI-12) identifying periods of extreme dryness during 1988–1989 and 2013–2014. The results show that 2013 was the driest year, while extremely dry and very dry conditions recurred in the years 1988, 1993, 1999, 2003, 2008, 2013, and 2017. This pattern reveals that dry seasons tend to occur every 4 to 6 years, averaging 5 years. The trend analysis of the SPI revealed an increasing trend across all monitoring stations, underscoring the influence of climate change on Syria, which may face an increased frequency of droughts in the future, thereby impacting water resource availability. The insights gained from this research could be instrumental in managing water resources and addressing the risks associated with climate change.