It is important to determine the limits of flow regimes in the design of stepped weirs because of the hydraulic performance of each regime. The present study investigates the effect of downstream slope and rock fill materials on flow regimes in gabion stepped weirs. Nine physical models of gabion weirs were used in the experiments. The models' downstream slopes ranged from 1:05 to 1:4 V:H. In addition, two types of rockfill materials: crushed stone of 0.42 porosity and rounded gravel of 0.38 porosity were used to study the effect of rockfill materials on flow regimes. The nominal size of the crushed stone was (37.5 mm -13.2 mm) D50 = 23 mm and the nominal size of the rounded gravel was (26.5 mm -13.2 mm) D50 = 16 mm. Each model has been tested with ten runs for discharge per unit width ranging (from 0.006 to 0.105 m 3 /sec. m) to cover all flow conditions and flow regimes. The onset of each flow regime for all physical models has been observed. The experimental data of the gabion stepped weirs have been used to develop equations to estimate the onset of each flow regime. The coefficient of correlation (R) of the developed equations ranged between 0.95 to 0.97. The results indicated on the steeper downstream slope models (1:0.5, 1:0.83), there is interference between the nappe and transition flow regimes. The nappe flow regime has not appeared on all steps at the same

The dynamic of nutrient cycling is a critical factor in riparian regions. It is essential to understand the behaviour of riparian areas in the maintenance and management river ecosystem. Sediment load, nutrients, and pathogens are transported to water bodies through land drainage and riverside flow. The classification of environmental agencies was poor for them. In this study, a qualitative investigation was implemented to determine the relationship between these practices and variations in nutrient retention for several types of riverbank soil. Also, the riverbank soils were including soil covered by wild reed plants. All the field works were along the Euphrates River in three locations. Moreover, study the variation in the content of vegetation riverbank soils from nitrogen, organic matter (OM), potassium (K), phosphorus (P), and PH. The results presented that riverbanks consider important locations for nutrient retention. Whilst agricultural activities have minimized the content of soil of OM (30%), N (49%), and K (3%), in subsurface soil but not so great lowering in surface layers. In contrast, management practices and human activities such as burning caused an apparent increase of OM (4%), N (77%), and a clear reduction in P (12%) content at both surface and subsurface layers of soil. Under all circumstances, riverbank soils showed a relative increase of nutrients at wet toe-slopes. Furthermore, it is noted that riparian vegetation and aquatic plants played a significant role by causing critical changes in riparian sides or even contrary effects on riverbank management practices and destruction of natural soil nutrient conditions. Thus, it should be carefully considered when evaluating the ecological impacts of riparian disturbances.

A well-known tool for assessing the quality of surface water is the water quality index (WQI) model. In this study, the WQI was generated to classify the water flowing in the Euphrates River in Qadisiyah Province. To develop analytical models, a connection between the findings and satellite images was developed. It is possible to determine what category a river's water quality for domestic use will fall into. The Weighted Arithmetic Water Quality Index (WWQI), Canadian Water Quality Index (CWQI), and Bascarón Water Quality Index (BWQI) were used to evaluate and examine the suitability of the Euphrates River in the city by analysing the water quality of samples taken from the five locations (Muhanawia (L1), Salahia (L2), Shamiyah (L3), Shamiyah (L4), Gammas (L5)). The hydrogen ions pH, temperature T, dissolved oxygen DO, nitrate NO 3 , calcium Ca, magnesium Mg, total hardness TH, potassium K, sodium Na, sulfate SO 4 , chlorine Cl, total dissolved solids TDS, and electrical conductivity ECvalues are provided for 2020 and 2021. Results showed the Euphrates River was deemed severely contaminated at location Gammas (L5) but acceptable at location Muhanawia (L1). During the research phase, the water quality for the Euphrates achieved a maximum of 87.43 using the CWQI for Muhanawia (L1) in 2021 and a minimum of 15.6 using the BWQI for Gammas (L5) in 2021. The excessive sulphate, total dissolved solids, calcium, and total hardness concentrations led to the low WQI. The results are analysed using a GIS, and a network database connected to the GIS is required to utilize its analytical capabilities and the geographically scattered data throughout the study region. The

Surface water and groundwater are significant for population and other activities due to the decreasing surface water flow toward Iraq. Therefore, there is a need to analyze groundwater’s quality and classification and its applicability as an alternative in various human activities in the study area. This study utilized the groundwater quality index model for drinking uses (GW.Q.I.) and entered the resulting values in the GIS environment. This model was applied to 56 wells in Al-Hillah city by measuring twelve variables in each well. The measured variables were calcium (Ca), magnesium (Mg), sodium (Na), chloride (Cl), sulfate (SO4), bicarbonate (HCO3), total hardness (TH), total dissolved solids (TDS), nitrate (NO3), and electric conductivity (EC). The prediction map of GW.Q.I. was produced in the GIS. Then, the distributing map was divided into six categories based on the suitability of groundwater for drinking uses. The areas’ values of six categories with their ratings were about 5 km2 (excellent), 122 km2 (good), 610 km2 (poor), 63 km2 (very poor), 36 km2 (contaminated), and 24 km2 (very contaminated). For the entire study area, the average value of the GW.Q.I. was 177, classified as poor for drinking uses.

Methane (CH4), and carbon dioxide (CO2) are only a few of the greenhouse gases that are significantly produced by humans and are found in landfills. This study presents an application of the Land GEM model to determine the environmental loads of dumping waste sites gases released from the landfill in Al-Hillah city, Iraq. The expected quantity of waste for the period (2023–2070) was used to calculate the environmental loads of dumping site gases. The quantified emission findings from loads of dumping site gases were contrasted with those from the model's default. The estimated landfill methane emissions from 2023 to 2070 total 874,904 tons of CH4, or an average of 18,227 tons of CH4 each year. The findings of the gas emissions demonstrated that local elements significantly influenced the output of loads of landfill gases. The anticipated loads of total landfill gases, methane, and carbon dioxide can be utilized as supporting data for policies on landfill-derived renewable energy. the results showed that methane gas can produce the average value of electricity power of 287,442 Mw/year from 2023 to 2070. This process will reduce the environmental problems brought on by loads of landfill gas emissions and get rid of cumulative solid waste.