Average Water Depth Research Articles

The influence of static versus dynamic pressure distribution strategies for modelling nonlinear waves generated by ships

A moving static pressure distribution is commonly used to simulate a travelling ship. However, the ship movement changes the fluid velocity around the hull, inducing pressures on the hull surface that are no longer equal to the static pressure. Therefore, we introduce a dynamic pressure correction strategy, which can accurately simulate the impact of the ship movement on the hull-surface pressure and preserve the desired hull shape under both stationary and transient conditions. The strategy is applied to a high-order spectral model and used to investigate ship-induced waves and wave resistance over a both flat and variable topography. We explore various parameters in our study, including the average water depth to ship draft ratio ( $h_0/d$ ), the channel width to ship width ratio ( $W/B$ ), the Froude number ( $Fr_0=U/\sqrt {gh_0}$ ) and variations in bathymetric slope. Compared with experiments on a flat bottom, the numerical results with dynamic correction show better accuracy in the simulation of ship-induced waves and wave resistance than those obtained using a static pressure distribution. The correlation coefficient for wake waves between the numerical and experimental results is improved by approximately 0.25 with the dynamic correction strategy. The amplitude and wavelength of ship-induced mini-tsunamis over a variable topography are found to be reduced when employing a dynamic correction compared with a static pressure distribution, and this effect becomes more pronounced with higher Froude number. The static pressure approach is shown to allow large deformations of the desired hull shape and changes in ship volume which are responsible for the different wave patterns from the two approaches.

Impact of lake expansion on the underwater topography: a case study of Lexiewudan and Yanhu Lakes on the Tibetan Plateau

ABSTRACT With increased precipitation and meltwater, most lakes on the Tibetan Plateau have expanded rapidly. However, the impact of erosion and sedimentation following lake expansion remains unclear. Using Lexiewudan and Yanhu Lakes as examples, we created a water depth inversion model using random forest method and combined it with lake bathymetric data and Landsat images and analyzed changes in underwater topography using SRTM and ICESat-2 data. The average water depths of two lakes were 5.92 and 9.82 m, and the root mean square error of inversion values were 0.85 and 0.93 m, respectively. Results showed that the underwater topography underwent considerable changes, in which at least half of the study areas experienced large topographic changes with 2–5 m. Lexiewudan Lake had a topographic change of more than 2 m in 61.28% of the total, while Yanhu Lake made up 69.78% of the total. The erosion and sedimentation volume of Lexiewudan Lake were 0.19 and 0.03 km3 and those of Yanhu Lake were 0.38 and 0.03 km3, respectively. Extensive underwater erosion and sedimentation are closely related to the original topography. Lake water movement, sediment transport, and permafrost degradation in flooded areas may also affect changes in underwater topography.

Bill Length of Non-breeding Shorebirds Influences the Water Depth Preferences for Foraging in the West Coast of India.

Body size, bill length and shape determine foraging techniques, habitat selection and diet among shorebirds. In this study, water depth preferences of different shorebirds with different bill sizes in various habitats including mudflats, mangroves at Kadalundi-Vallikkunnu Community Reserve (KVCR) (19 shorebird species) and adjacent agroecosystems at Vazhakkad (12 species) were studied between 2017 and 2020. The bill length of the shorebirds was significantly and positively associated with the average water depth, where shorebirds were observed to forage. Shorebirds with shorter bill lengths preferred shallow waters and those with longer bills preferred deep waters for their foraging activities. Habitat type also had a significant effect on the shorebird occurrence. Eurasian Curlews in both mangroves and mudflats were observed in areas with a higher water depth compared to other species. This is due to the fact that shorebirds tend to specialise in feeding habitats or in prey items to reduce intraspecific competition and distribute themselves in space and time in accordance with the availability of their resources. The occurrence of some species in agroecosystems is attributed to the reduced food availability, habitat quality and other disturbances for shorebirds on tidal flats, which are critical for sustaining migratory phenology. The differences in bill morphology are crucial in determining diet, water depth, niche preferences and segregation. Morphological characters and hydrological rhythms determine specialisation in diet and habitat preference in shorebirds.

Hydrological Connectivity Response of Typical Soil and Water Conservation Measures Based on SIMulated Water Erosion Model: A Case Study of Tongshuang Watershed in the Black Soil Region of Northeast China

The black soil region of Northeast China is the largest commercial grain production base in China, accounting for about 25% of the total in China. In this region, the water erosion is prominent, which seriously threatens China’s food security. It is of great significance to effectively identify the erosion-prone points for the prevention and control of soil erosion on the slope of the black soil region in Northeast China. This article takes the Tongshuang small watershed (Heilongjiang Province in China) as an example, which is dominated by hilly landforms with mainly black soil and terraces planted with corn and soybeans. Based on the 2.5 cm resolution Digital Elevation Model (DEM) reconstructed by unmanned aerial vehicles (UAVs), we explore the optimal resolution for hydrological simulation research on sloping farmland in the black soil region of Northeast China and explore the critical water depth at which erosion damage occurs in ridges on this basis. The results show that the following: (1) Compared with the 2 m resolution DEM, the interpretation accuracy of field roads, wasteland, damaged points, ridges and cultivated land at the 0.2 m resolution is increased by 4.55–27.94%, which is the best resolution in the study region. (2) When the water depth is between 0.335 and 0.359 m, there is a potential erosion risk of ridges. When the average water depth per unit length is between 0.0040 and 0.0045, the ridge is in the critical range for its breaking, and when the average water depth per unit length is less than the critical range, ridge erosion damage occurs. (3) When local erosion damage occurs, the connectivity will change abruptly, and the remarkable change in the index of connectivity (IC) can provide a reference for predicting erosion damage.

Trends in American Alligator Pods in Arthur R. Marshall Loxahatchee National Wildlife Refuge

Abstract American alligators are an important component of the Greater Everglades, serving as ecosystem engineers, predator, and prey and are tightly tied to water depth patterns. Because of their importance to ecosystem function and link to hydrology, American alligators are an ecological indicator for Everglades restoration. I used data from fall nighttime spotlight surveys of American alligators in the Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida, to describe the trend in number of hatchling pods from 1998 to 2021 and relate that trend to hydrologic parameters hypothesized to influence American alligator production. I used an information-theoretic approach to evaluate 14 models created from combinations of year of observation and three hydrologic variables: average and range in water depth from 16 April of the previous year to 15 April of the nesting year (breeding potential window) and average water depth from 16 April to 31 May of the nesting year (courtship and mating window). Number of pods ranged from 16 in 1998 to 0 in 2011. Each of the four top models included year and one or more of the hydrologic variables as predictors and explained 26–34% (D-squared) of the variation in number of pods. Year was the predictor for which the 95% confidence interval (CI) did not contain 0 and indicated a declining trend (from −3 to −8%; 95% CI). I included all hydrologic variables in the top models, indicating that they contribute some information to explaining the trend; however, contrary to my hypotheses, there was not a clear relationship between any of the hydrologic variables and number of American alligator pods. I based my hypotheses on information synthesized in the American alligator production suitability index model used in Everglades restoration planning, and my results suggest the need for additional refinement of that model.

Fluvial habitat associations of riverine dragonflies (Odonata, Gomphidae) in the Huron Mountains (Michigan, USA)

AbstractThe presence of sediment‐burrowing clubtail dragonflies (Gomphidae) may be directly related to riverine geomorphic properties. Their synchronous emergence behavior, marked by persistent exuviae, allows for the examination of emerging adult‐stage habitats. Here we explore how emerging adult and benthic larvae are related to hydrogeomorphic factors through regression modeling. Nine sites in two subwatersheds of the Huron Mountain region (Michigan, USA) were surveyed during two periods: May/June 2021 and August 2021. Temperature, pH, dissolved oxygen, conductivity, and discharge were measured concurrent with invertebrate surveys, and field samples of total suspended solids, nutrients, and substrate particle size distribution were also taken. In spring, 317 exuviae were collected, including 153 Gomphidae. In August, 45 larvae were collected including 22 Gomphidae. Spearman's rank correlations preceded robust regression analysis to aid variable selection. Although nonsignificant, Gomphidae exuviae were negatively correlated with conductivity, average water depth, and percent sand while non‐Gomphidae exuviae were positively correlated with the same variables. The model selection found the top models for Gomphidae and non‐Gomphidae exuviae abundance to relate to depth and conductivity, while the top model for Gomphidae larvae was with discharge. All single variable models (discharge, width, and percent sand) had similar AICc criterion values when examining their relationship with non‐Gomphidae larval abundance. Our study demonstrates that larvae of several riverine dragonfly taxa in the Huron Mountains co‐occur despite hydrogeomorphic variation, yet, at emergence, specific taxa may be responding to different stream properties. Understanding the habitat requirements of riverine dragonflies and how these potentially shift throughout development can support conservation efforts.

Responses of ancient reservoir sediments to water level fluctuations, human activity and climatic changes over the past ∼700 yr in Guizhou Province, southwestern China

Knowledge of the responses of reservoir ecosystems to anthropogenic and climatic impacts on multi-centennial timescales is relatively poor, but is crucial for the management of numerous reservoirs in China. In this study, the history of an ancient reservoir system was reconstructed for the last ∼ 700 yr based on multiple dating methods (210Pb, 137Cs, and 14C) and geochemical data (e.g., the mass accumulation rates, loss-on-ignition values, total organic carbon, total nitrogen, total phosphorus contents, and stable carbon isotope ratios of organic matter) obtained for sediment cores from Gongqing Reservoir in Guizhou Province, southwestern China. Combined with historical literature and regional climatic records, the response of the aquatic ecosystem in Gongqing Reservoir to water level fluctuations, anthropogenic activity, and climatic changes during the last ∼ 700 yr was assessed. The results suggest that dramatic changes in the water level due to dam heightening in 1950 s significantly changed the aquatic ecosystem of Gongqing Reservoir. During periods of low water levels (average water depth = 1–2 m; 1345–1957 CE), aquatic macrophytes contributed more to the sedimentary organic matter, whereas phytoplankton increasingly contributed more during periods of high water levels (∼5 m; 1957–2020 CE). During the late stage (1700–1957 CE) of low water levels, the reservoir ecosystem was significantly affected by human activities. Combined with regional geological and historical records, we consider that increased population and enhanced human activities have markedly affected vegetation conditions in western Guizhou Province since ∼ 1700 CE. After 1957 CE, anthropogenic activities were key in affecting the aquatic ecosystem of Gongqing Reservoir. Especially in the last decade, large housing developments and enhanced agricultural activities in the watershed have led to enhanced catchment erosion and transport of more nutrients into the reservoir, thus promoting the algae productivity. These results provide new insights into how reservoir ecosystems respond to water level fluctuations, anthropogenic activity and climatic changes on multi-centennial timescales.

Bringing vision to climate: A hierarchical model for water depth monitoring in headwater streams

Stream-observing cameras have recently been deployed in stream systems to monitor water depth dynamics. However, most existing image-based water depth monitoring methods require additional gauging equipment, extensive manual annotations, or complex manual calibration. In this paper, we propose the hierarchical model, a novel multi-modal and multi-scale deep learning framework for monitoring water depth in headwater streams with only a field camera capable of night vision and no additional equipment. In particular, the hierarchical model integrates long-term dynamic patterns extracted from large-scale meteorological data with short-term dynamic patterns extracted from small-scale stream image data to jointly monitor water depth at a fine-level temporal resolution. In order to overcome the issue of limited availability of images, we introduce a transfer learning strategy and incorporate more accurate long-term patterns that enable the hierarchical model to perform competitively even with a small number of images. We evaluate our method on a real-world headwater stream monitoring dataset from the West Brook study area in western Massachusetts, United States. Our extensive experiments demonstrate that the hierarchical model outperforms several state-of-the-art methods for water depth monitoring, and that more accurate long-term patterns can better guide the monitoring of short-term patterns with excellent flexibility and less computational cost. The mean absolute error of our hierarchical model achieves a remarkable level of 4.9cm at the study site with 0.89m average water depths, and only 12.5cm at more drastically varied site with 3.95m average depths.

The large‐scale restoration of fire and water regimes in Everglades National Park reveal little change in plant diversity along an elevational gradient

Quantifying the response of plant diversity to large‐scale restoration is essential for measuring management success. One of the world's largest restoration efforts began in 2000 in the Everglades ecosystem in Florida, United States, through the Comprehensive Everglades Restoration Plan. In coordination with ongoing fire management, this restoration effort aims to restore natural hydrologic and fire regimes in this dynamic ecosystem. Restored water and fire regimes in the Everglades interact along an elevational gradient between seasonally inundated marl prairie and frequently burned pine rockland on Long Pine Key in Everglades National Park. To determine the impact of management on plant community richness and composition, we resampled transects spanning the elevational gradient between marl prairie and pine rockland initially sampled prior to the implementation of current restoration efforts (circa 1997–1999). We measured percent plant cover and developed generalized linear mixed models to determine the effects of fire frequency, average water depth, and elevation on plant species richness and composition across the two time periods. Additionally, we used species‐level random effects to examine how individual species respond to each environmental variable. We failed to detect any systematic shifts in plant composition in response to fire and water management. However, we found that complex interactions between fire and water structure plant composition and maximize species richness along gradients of water depth and elevation, with low, moderate, and high burn frequencies increasing richness in wet, moderately wet, and dry sites, respectively.

An insight into the prokaryotic diversity from a polymetallic nodule-rich region in the Central Indian Ocean Basin using next generation sequencing approach.

Deep sea is a vast, dark, and difficult-to-access terrain and is now looked upon as a unique niche harboring diverse microorganism. We used a metataxonomic approach to decipher the microbial diversity present in the water column (surface to near bottom), water overlaying the sediments, and the deep-sea sediments (up to 35 cm) from the Indian Contract Region (ICR) in the Central Indian Ocean Basin (CIOB). Samples were collected from #IRZ (Impact Reference Zone), #PRZ (Potential Reference Zone), and #BC20 (Control site, outside potential mining area) with an average water depth of 5,200 m. 16S rRNA (V3-V4 region) amplicon sequencing on the MiSeq platform resulted in 942,851 ASVs across 65 water and sediment samples. Higher prokaryotic diversity was observed below 200 m in the water column to the seafloor. Proteobacteria was the most dominant bacterial phylum among all the water samples while Firmicutes, Actinobacteria and, Bacteroidota dominated the sediments. Sediment (below 10 cm) was co-dominated by Firmicutes. Thermoplasmata was the dominant archaeal group in the water column while Crenarchaeota was in the sediments. BC20 was less diverse than IRZ and PRZ. Deep Sea microorganisms could play a vital role in the mineralization processes, nutrient cycling, and also different biogeochemical cycles.

Deep sediment characterization from very low-frequency features from merchant ships

The very low-frequency noise from merchant ships provides a good wideband source to study the deep layers of the seabed. The nested striations which characterize ship spectrograms contain unique acoustic features where the waveguide invariant (β) becomes infinite. This occurs at frequencies between 20 and 80 Hz where pairs of modal group velocities are equal. The goal of this project was to identify the β = ∞ frequencies in ship noise spectrograms and use these frequencies to perform statistical inference for the deep layer sound speeds and thicknesses. The Seabed Characterization Experiment of 2022 on the New England continental shelf had three vertical line arrays strategically placed between two shipping lanes. The average water depth was 75 meters with less than one meter bathymetry change between the arrays. The results of this study are based primarily on five ships. There was a gradual shift in the β = ∞ frequencies between the three arrays, suggesting a gradual change in the deep sediment layers. [Work supported by Office of Naval Research.]

Study on the Spatial–Temporal Variations and Driving Factors of Water Yield in the Yiluo River Basin

Water yield (WY) is an significant characteristic that reflects ecosystem services. In order to realize high-quality development, it is vital to explore the spatial and temporal (ST) distribution of WY and its driving factors in the Yiluo River Basin (YLRB) to uphold ecological stability and advance long-term sustainable growth. This paper quantifies WY in the YLRB from 2010 to 2020 using the WY model in the InVEST toolkit. Exploring ST characteristics and driving factors at both the raster and sub-watershed levels, results indicate that the overall WY (average water depth) of the YLRB in 2010, 2015, and 2020 was 26.93 × 108 m3 (136.50 mm), 22.86 × 108 m3 (113.38 mm), and 26.81 × 108 m3 (137.61 mm), respectively. The spatial pattern of watershed WY remains consistent across various periods, illustrating spatial variation in the depth of low WY in the central and western regions and high WY depth in the eastern region. At the sub-watershed level, the Luo River (LR) Basin has the highest contribution (69%) to the WY of the entire basin and served as the principal WY region of the YLRB. Conversely, the Yiluo River section, formed after the confluence of the Yi River (YR) and the LR, has the lowest WY contribution (7%) in the entire watershed. Distinct variations exist in the WY capacity among various land use (LU) types. Construction land (CSL) and unused land (UL) exhibited the highest WY capacity (315.16 mm and 241.47 mm), whereas water area (WA) had the lowest (0.01 mm). WY was significantly positively correlated with slope, precipitation, actual evapotranspiration, percentage of cultivated land, and NDVI. It showed a significant negative correlation with altitude, WA, and population density. This study helps promote the research and development of watershed ecosystem services. It also provides scientific support resolving conflicts between watershed protection and economic development and promoting harmony in the YLRB.

Experimental investigation on strength characteristics of marine soft clay under monotonic and cyclic loading

Sea areas with an average water depth of 5-15 m in the East China Sea are mostly muddy soft-foundation seabed. The wind power infrastructure built on them must fully consider the mechanical properties of marine soft clay during design process. In this study, monotonic and cyclic tests were conducted to study the strength characteristics of soft clay at various strain rates, cyclic stresses and initial effective vertical stresses using a simple shear apparatus. The test results showed that, as the strain rate increased, the peak shear stress of the samples under different confining pressures increased. However, the failure lines of the effective stress path of samples under different strain rates and vertical stresses are uniform. Compared to the traditional cyclic failure criteria, the failure criterion based on the inflection point of double amplitude strain can reflect the deformation characteristics of the specimen more accurately. The peak shear strength obtained from the monotonic tests was used to normalize the cyclic stress. Subsequently, the relationship between the number of failure cycles and normalized cyclic stress level of the soft clay specimens was established.

Analysis of the hydraulic interference between the baffles and the composite hydraulic structure

The purpose of the present study is to examine the influence of baffles presence at downstream system on weir gate hydraulic response. Two baffles configuration (triangle and angle shapes) are installed in bed flume. Two different spacing are used between the baffles and two different directions for baffles are also adopted. The study tries to investigate the variation in upstream Froude number, downstream Froude number, Reynolds number, actual discharge, discharge coefficient, downstream average water depth and the hydraulic system efficiency which is expressed as function of downstream water depth. It has been shown that the number of baffles has a direct and significant impact on flow hydraulic characteristics of weir-gate structure regardless of the spacing between baffles and the direction of baffles related to flow. Baffles number and spacing have essential impact on the water flow velocity of system and this impact leads to increase the flow resistance. The results clarify that the upstream Froude number, downstream Froude number, Reynolds number, actual discharge and discharge coefficient are decreased with the increase in baffles number except the average downstream water depth which increases with increase in baffles number. The efficiency of hydraulic system gives a good indicator for using baffles with weir-gate structure. At the end this paper shows a fruitful result of efficiency. This experiment run condense on the baffle’s numbers and directions with respect to the water flow direction at the downstream regime. So, the rises in the water level relies on the numbers and directions of the baffles as compare to the case without using baffles at the flume downstream region. The actual discharge and weir-gate discharge coefficient are more sensitive to the increase in the baffles’ numbers and the baffles direction with respect to the water flow direction

King Rail (Rallus elegans) presence in the Midwestern United States is predicted by local-scale factors and avian community.

The King Rail (Rallus elegans) is a wetland dependent species of conservation concern. Our objective was to gain a better understanding of the breeding habitat associations of King Rails in the Midwestern United States and the relationship of this species to other obligate marsh birds using occupancy and MaxEnt models. To collect data pertaining to occupancy, we placed trail cameras at 50 random points in coastal wetlands in the western Lake Erie basin where calls of King Rails were continuously broadcast at night. Data pertaining to other marsh bird species were collected via call-broadcast surveys and camera surveys at each sample point. For MaxEnt modeling, we obtained presence data for King Rails and other obligate marsh birds from eBird and habitat data from GIS databases. Trail cameras and call-broadcast surveys captured 10 detections of King Rails at nine sites, an 18% naive occupancy rate. King Rail occupancy was positively related to amount of interspersion, average water depth, and percent cover of emergent vegetation at local scales within a 5-m radius. Our MaxEnt models indicated that, at a broader scale, the presence of other rail species such as the Sora (Porzana carolina) may be more important for predicting King Rail presence than other marsh birds or coarse wetland categories such as "emergent vegetation." Our results could help wetland managers to predict where King Rails occur and to adapt management plans to incorporate King Rail conservation.

Numerical Simulation and Sensitivity Analysis of Sediment Issues in Pumped Storage Power Stations: Sediment Conveyance of Turbine and Sedimentation of Reservoirs

In this paper, a 1D process-based numerical model is established to study the sediment concentration via the turbine (TSC) and sedimentation of the lower reservoir and the upper reservoir of a certain pumped storage power station (PSPS), which is intended to be built on a sandy river. In addition, the sensitivity of TSC to some factors, such as suspended sediment gradation, the water level of the lower reservoir, and the coefficients of the sediment-carrying capacity formula, are analyzed in this paper. It is revealed that (1) the TSC will decrease by 30.8~34.5% when the incoming sediments of particle sizes less than 0.002 mm (which accounts for 3.95% of the totality) are replaced with incoming sediments of particle sizes between 0.002 mm and 0.004 mm. At the same time, the sedimentation thickness of the upper reservoir will decrease by 20.9%, and the siltation rate of the lower reservoir will increase by 2.4%. (2) The TSC will decrease by 12.6~13.1% as the water level of the lower reservoir rises by 17.55 m. This represents an increase of 8.4% in the average water depth and 26.4% in the storage capacity of the lower reservoir. At the same time, the sedimentation thickness of the upper reservoir will decrease by 32.2%, and the siltation rate of the lower reservoir will increase by 2.5%. (3) The TSC will decrease by 1.2~1.4% as the index of the sediment-carrying capacity formula m changes from 1.12 to 0.666, and the coefficient of the sediment-carrying capacity formula K changes from 0.2 to 0.6. At the same time, the sedimentation thickness of the upper reservoir will decrease by 7.2%, and the siltation rate of the lower reservoir will increase by 1.7%. Through the research on the sensitivity of the TSC, the direction and amplitude of the TSC changes with the boundary conditions are found, which provides a basis for the scheme comparison of specific projects and further supplements the prediction method system of the TSC. Meanwhile, the results remind researchers to pay more attention to the determination of boundary conditions and also provide the basis for the error analysis of the TSC. In summary, the results have certain guiding significance for the related research, and the sensitivity analysis results of the case could provide a reference for other specific projects.

Environmental DNA revealed high accuracy in detection of the Eurasian otter in Himalaya

Abstract A precise framework of species occurrence and distribution trends is crucial for conservation measures. Traditional survey methods are often labour‐intensive and time‐consuming, and they can be ineffective in detecting the presence of rare and elusive taxa, especially in harsh environments. The effectiveness and feasibility of an environmental DNA (eDNA)‐based approach was tested to detect the occurrence of the semiaquatic Eurasian otter (Lutra lutra) in six rivers in the Trans‐Himalaya, comparing the results with those obtained from a traditional field survey. Water samples were collected and filtered on‐site at 15 locations, from 2,660 to 3,819 m a.s.l. Otter scats were actively searched for at the same locations in a 900 m buffer along the river bank. Fifteen environmental parameters were recorded at each sampling site. After eDNA extraction and target quantitative realt‐time polymerase chain reaction (qPCR) assay, statistical analyses were run to explore the relationship between environmental factors and the presence/absence of otters at each site. Otter DNA was found at 73% of sites, whereas traditional field survey results showed that 53% of sites were positive for otters. Results from principal component analysis showed that the sites avoided by otters, as measured through eDNA, were clearly segregated along PC1 and PC2, with both axes explaining 57% of the cumulative variance. The best‐performing generalized linear model suggested that the occurrence of otter eDNA was influenced by channel width, surface velocity, nitrate level, total dissolved solids, and average water depth. The results of this study highlight that, compared with traditional field surveys, eDNA‐based methods increased the detection of positive sites by 20%, thus demonstrating their reliability for monitoring the presence of otters in the study area and providing new insights into the ecology of this species in the Indian Trans‐Himalaya.

Estimation of the runoff of the Qalatopzan and Parewla Basins using the (SCS-CN) model

In this study, water runoff estimation by SCS-CN model for both Qalatopzan and Parewla watersheds which located in northeastern of Iraq and eastern part of Kurdistan Region in Kalar district, and lies on latitude (34o:51-: 33=) and (35o :04-: 52=) north and longitude (45o:21-: 50=) and(45o :34-: 59=) east thet located in the semi-mountainous area. The total catchment area is about (235.46 km2), and Qalatopzan watershed with an area of ​​(148.74 km2) with a rate of (63.17%) and Parewla drainage with an area of ​​(86.72 km2) and (36.83%) form the research area which distributed into two main streams and (8) Sub-watersheds, each of which includes four minor sub-watersheds. Rainfall irregularities accompanied by environmental and climatic effects have created water shortage problems for the study area, especially during the dry seasons, and in order to achieve the research objective which is to determine the amount of water flowing and appoint the level of utilization of hydrology of both watersheds, each of its files (DEM12.5m), aerial imagery (Landsat8 OLI), Geographic Information Systems and Remote Sensing (GIS & RS) techniques were used. After taking (10) soil samples and determining the numerical value of soil turbidity and humidity and the appearance of (7) different land uses and taking a wave of rainfall. The study concluded that the average depth of the runoff water in the study area is equal to (22.41 mm) which is (24.72 mm) in the main watershed of Qalatopzan and (20.11 mm) in the main watershed of Pariole, and the water flowing is about (2,60m3), while in the main reservoir of Qalatopzan (3.34m3) and in Parewla is (1.77m3). Finally, the results obtained are an important basis for the development of water harvesting and exploiting plans, so as to meet water needs and sustain human activities along the border of both brooks.

The Effect of Operating Pressures and Speed Ratios on The Evaluation Criteria of The Center Pivot Irrigation System (Valley) in Al Baghdadi Region

A study conducted during the 2021winter season in Al Baghdadi region (150) km west of Ramadi City (Iraq) to show the effect of operating pressure and equipment speed on evaluation criteria of the center Pivot Irrigation Systems. Three operating pressures were used in the experiment, which are 25, 30 and 35 pounds inch−2, with three speeds of 25%, 50% and 75% for each pressure. Study result showed that The pressure 30 pounds inch−2 achieved the highest values for the average of the studied traits, as it was 97.22% while the lowest value was recorded at a pressure 25 pounds inch−2 which amounted to 88.70% with a decrease Ratio 9.6%. The pressure 35 pounds inch−2achieved the lowest average water depth 24.13 mm, while the highest average depth of water was at pressure 30 pounds inch−2 35.89 mm with a height Ratio 32.7%. The lowest average value of the water depth variance (qvar.) was 8.34% at pressure 30 pounds inch−2 while the average of this value increased to 28.63% at pressure 35 pounds inch−2 with increase 70.8%. The ratio of the rotational speed of the arm of the system significantly affected the values of each of the studied traits, the velocity 25% achieved the highest average values 30.93 mm and 93.10%, while the speed 75% achieved the lowest rate 26.58 mm and 89.63% With a decrease 16.4% and 3.8% for each of the applied water depth and Uniformity coefficient, respectively. This speed 25% also achieved the lowest average water depth variance, which amounted to 16.02%, while speed75%achieved the highest value of water depth variance, which amounted to 26.59%, with an increase rate 39.7%.

AICSS: Automatic simulator–controller/optimizer model of open channels

AbstractThe coupling between simulators and controllers in control systems of irrigation canals has always been a challenging issue. Consequently, simplified or approximated models of Saint‐Venant equations (SVEs) have unavoidably been used thus far. In this research, a coupled simulator–controller/optimizer model named Automatic Irrigation Canal Simulation System (AICSS) was developed to control irrigation conveyance system simulation (ICSS) using MATLAB, which allows setting input data, retrieving input or output data and opening, running and closing the ICSS model, enabling any real‐time modelling of canals with mathematical and statistical experiments as well as calibration of the discharge coefficient and Manning's roughness. To this end, several submodels were written in FORTRAN to automatically guide orders in ICSS received from MATLAB. The developed model is started by pressing the F5 key in MATLAB. To introduce the AICSS application and evaluate it, the proportional‐integral‐derivative (PID) controller was used and tested in the E1R1 Dez and Aghili East canals located in Khuzestan province (Iran), showing successful results when simulating and controlling the canals and leading to maximum and average water depth errors of 2.3% and 0.07% in the E1R1 canal and 5.3% and 0.36% in the Aghili East canal, respectively.