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The evolution of Neolithic to Bronze Age settlement organization in Central Europe has revealed ditches as an important component of settlement structures. The various shapes and sizes of these features contribute to different understandings of their functions, mainly referring to ditches as elements of fortifications or ritual practices. Based on a newly discovered Copper Age feature at Kamianets-Podilskyi (Tatarysky), Ukraine, our paper contributes to the discussion on the function of ditches in their relation to prehistoric technologies. This study presents evidence on tanning techniques and technologies associated with a section of ditch belonging to the Western Trypillia culture. Due to the uniqueness of this discovery, we applied various analyses, including GIS spatial analyses, palynological, anthracological, archeozoological, malacological, and use-wear studies. The obtained results enable us to recognize the complex practices of Copper Age communities, skillfully combining technical knowledge with an understanding of environmental conditions. [ABSTRACT FROM AUTHOR]

The installation of drainage ditches and removal of vegetation in preparation for vacuum harvesting alters the carbon dynamics of peatlands. However, we lack the measurements to understand the spatial distribution and environmental and substrate quality controls of carbon dioxide (CO2) and methane (CH4) emissions, as well as how these factors change over the 20–30 year extraction period. For three summers, we measured CO2 and CH4 emissions using the closed chamber method at three actively extracted peatlands near Drayton Valley, Alberta, ranging from 2 to 28 years since the start of extraction. Measurements were made in the ditches, and on segments of peat (fields) between adjacent ditches. Field emissions did not change with distance from ditches, likely due to the observed homogeneity of volumetric water content (VWC) and temperature across the fields. Understanding carbon dynamics in the ditches will be important, as they emitted on average two and 10 times, respectively, the amount of CO2 and CH4 per square meter of the fields. We found moderate to weak relationships between carbon emissions and soil temperature, VWC and ditch water level, though ditch emissions were significantly reduced when there was standing water present. Altering conventional site management, such as increasing ditch spacing, could substantially reduce CH4 emissions from the managed area. Emissions did not decrease with time since start of extraction. We suggest that Canadian emission factor calculations for land‐based emissions consider both peat quality variations among sites, and a site's extraction duration, which has been important in other studies. Plain Language Summary: Peat extraction for use in horticulture growing media contributes to peatland disturbance in Canada. In preparation for extraction, drainage ditches are dug to dry out the surface peat, and the vegetation is removed. These actions shift these sites from net stores of carbon, to net emitters, including the release of carbon dioxide (CO2) and methane (CH4), two powerful greenhouse gases. Few studies have quantified carbon emissions during the extraction period. To address this, we measured CO2 and CH4 emissions from actively extracted sites in Alberta, Canada for three summers, focusing on the spatial distribution and environmental controls of the emissions. We found that the drainage ditches were hotspots of emissions, emitting two and 10 times, respectively, the amount of CO2 and CH4 per meter squared of the non‐ditch portion of the site. We also found that emissions from the peat fields did not change with distance from the drainage ditches. More research is needed to better understand these water‐carbon interactions. Our work can support management practices that reduce these carbon emissions to help create a more sustainable industry. For example, we found that reducing the number of drainage ditches at a site could substantially reduce total methane emissions. Key Points: Drainage ditches emitted on average two and 10 times the amount of carbon dioxide and methane per square meter compared to the fieldsIncreasing drainage ditch spacing should be considered as a management strategy to substantially reduce CH4 emissionsLimited spatial variability in field carbon emissions, with no observed change with distance from the drainage ditches [ABSTRACT FROM AUTHOR]

The design of ditch structures in ship locks has an important influence on reducing water flow energy, improving the uniformity of water filling in lock chambers, and reducing the force acting on mooring ships. Existing studies on the mechanisms of flow fields and mooring conditions under the influence of geometric structural changes in ditches are insufficient, and research is limited by the complexity of the problem. Based on OpenFOAM v8, a numerical simulation of the flow structure in a lock chamber was carried out. Taking into account the ditch width, ditch depth, and sill height of the side wall as the research variables, the influence of structural changes in four single ditches on the uniformity of water filling in the lock chamber is systematically discussed. The results show that under a complex boundary constraint, the flow is diffuse in the ditch and the lock chamber, and the filling of the lock chamber is not uniform. The uniformity of water filling is closely related to the arrangement of the ditch geometry. Through the comprehensive analysis of multiple factors, some parameter thresholds were obtained to provide theoretical guidance for ditch design. It is hoped that through improved design, allowing an increase in the uniformity of water filling, the lock chamber will reach a relatively optimal state. [ABSTRACT FROM AUTHOR]

Alterations of natural hydrology in aquatic ecosystems are known to strongly impact the community composition of different taxa. Surprisingly, literature on the potential influence of hydrology on fish community composition is still very scarce in agricultural marshes, where canals represent one of the few remaining aquatic habitats. This study is aimed to address this research gap by monitoring fish communities in independent hydrological units differing in hydrology management over a 6 years period. We predicted variable fish responses to the hydrological context according to different life‐history strategies (opportunistic, equilibrium, or periodic species). Periodic and opportunistic species were the most frequently observed. Despite differences in hydrology between canals (but little variation over years), we found that hydrology explained only a very low proportion of variation in the composition of fish communities. In particular, the flooding duration of meadows in early spring did not influence the composition of fish communities, not even the abundance of periodic species expected to rely on such temporary habitats. Instead, fish communities were more influenced by local habitat variables (aquatic vegetation cover, turbidity, tree roots, and refuges under the canal banks). The hydrological management of most hydrological units for agricultural purposes (i.e., severe flood abatement in spring and shallow water depth in canals in summer) was found to be incompatible with conservation goals to promote more diverse fish communities between hydrological units. Therefore, we call for further investigations in similar habitats covering a larger range of hydrological conditions. [ABSTRACT FROM AUTHOR]

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Copyright of Spal: Revista de Prehistoria y Arqueologia de la Universidad de Sevilla is the property of Spal. Revista de Prehistoria y Arqueologia de la Universidad de Sevilla and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The design of ditch structures in ship locks has an important influence on reducing water flow energy, improving the uniformity of water filling in lock chambers, and reducing the force acting on mooring ships. Existing studies on the mechanisms of flow fields and mooring conditions under the influence of geometric structural changes in ditches are insufficient, and research is limited by the complexity of the problem. Based on OpenFOAM v8, a numerical simulation of the flow structure in a lock chamber was carried out. Taking into account the ditch width, ditch depth, and sill height of the side wall as the research variables, the influence of structural changes in four single ditches on the uniformity of water filling in the lock chamber is systematically discussed. The results show that under a complex boundary constraint, the flow is diffuse in the ditch and the lock chamber, and the filling of the lock chamber is not uniform. The uniformity of water filling is closely related to the arrangement of the ditch geometry. Through the comprehensive analysis of multiple factors, some parameter thresholds were obtained to provide theoretical guidance for ditch design. It is hoped that through improved design, allowing an increase in the uniformity of water filling, the lock chamber will reach a relatively optimal state.

The drainage ditches of the North Carolina Coastal Plain retain ecological structural characteristics of the wetlands they often replace. We surveyed 32 agricultural, freeway, and forested ditch reaches across this region for hydrologic indicators, soil organic matter, and plants. All showed at least some hydrologic indicators and had soil organic matter, especially swampy forests. Twenty-nine of 32 had hydrophytic herbaceous plant assemblages according to US Army Corps of Engineers wetland delineation standards. These varied and rich herbaceous assemblages differed among site types, and sorted according to influences including apparent human restriction of vegetation growth, wetness, and surrounding land use. These results suggest that management can nudge agricultural and freeway ditch herbaceous communities to resemble those of forests, which were typically more hydrophytic and native. The US National Hydrography Dataset and the National Wetlands Inventory excluded most sample sites, and mischaracterized most they did include as natural waterbodies. This lack appears not to arise from technical limitations; data and tools to resolve it are well established. These ditches’ underrecognized but likely vast extent, wide ranges of variability, and apparent response to management suggest that humans’ ability to cultivate wetland structure in these manmade aquatic ecosystems throughout the North Carolina Coastal Plain and beyond is already immense, with even larger potential. [ABSTRACT FROM AUTHOR]

Minor archaeological works completed at Wellmeadow Street, Paisley between 2017 and 2018 have identified evidence of prehistoric activity in the centre of the city. Comprising a single prehistoric feature and a shafthole stone, the finds from these works demonstrate the importance of archaeological mitigation, even in areas of low expectation. [ABSTRACT FROM AUTHOR]

Ditches of forestry-drained peatlands are an important source of methane (CH4) to the atmosphere. These CH4 emissions are currently estimated using the IPCC Tier 1 emission factor (21.7 g CH4 m−2 y−1), which is based on a limited number of observations (11 study sites) and does not take into account that the emissions are affected by the condition and age of the ditches. Furthermore, the total area of different kinds of ditches remains insufficiently estimated. To construct more advanced ditch CH4 emission factors for Finland, we measured CH4 emissions in ditches of 3 forestry-drained peatland areas (manual chamber technique) and amended this dataset with previously measured unpublished and published data from 18 study areas. In a predetermined 2-type ditch classification scheme, the mean CH4 emissions (±standard error) were 2.6 ± 0.8 g CH4 m−2 y−1 and 20.6 ± 7.0 g CH4 m-2 y−1 in moss-covered and moss-free ditches, respectively. In a more detailed 4-type classification scheme, the yearly emissions were 0.6 ± 0.3, 3.8 ± 1.1, 8.8 ± 3.2, and 25.1 ± 9.7 g CH4 m−2 y−1 in Sphagnum-covered, Sphagnum- and vascular plant—covered, moss-free and vascular plant-covered, and plant - free ditches, respectively. Hence, we found that Tier 1 emission factor may overestimate ditch CH4 emissions through overestimation of the emissions of moss-covered ditches, irrespective of whether they harbor potentially CH4 conducing vascular plants. Based on the areal estimates and the CH4 emission factors for moss-covered and moss-free ditches, CH4 emissions of ditches of forestry-drained peatlands in Finland were 8,600 t a−1, which is 63% lower than the current greenhouse gas inventory estimates for ditch CH4 emissions (23,200 t a−1). We suggest that the Tier 1 emission factor should be replaced with more advanced emission factors in the estimation of ditch CH4 emissions of boreal forestry-drained peatlands also in other countries than in Finland. Furthermore, our results suggest that the current practice in Finland to minimize ditch-network maintenance by ditch cleaning will likely decrease CH4 emissions from ditches, since old moss-covered ditches have very low emissions.

The second part of the article deals with the issues of tracing and dating the external line of the fortifications of the city of Bolgar, which existed in pre-Mongol times. The task of this line was to defend the territory adjacent to the citadel and inhabited by craftsmen and tradesmen. Until now, it was assumed that there was only one such line. However, excavation materials indicate several lines (at least two). The problem is aggravated by very approximate dating of the ditches discovered during excavations and the absence (or extremely low degree of preservation) of embankments, which are no longer visible in the relief. Lack of reliable information about the fortification of the Bolgar at the beginning of the 13thcentury casts doubt on the catastrophic destruction of the city by the Mongols in 1236.

In the wooded landscapes on the last northern slopes of the mountain Cer, a very well-preserved palisade ditch enclosure of small dimensions and a regular circular shape was discovered (site of Šančina, Desić village). Over the last few years, archaeological excavations at this site have focused on the inner space, bordered by a massive ring-shaped earthen rampart. An unusually wide and deep ditch surrounds a high earthen embankment of flattened conical shape, bordered on the inside by a palisade ditch, with traces of densely packed and deeply buried wooden posts. The excavations so far have not revealed any interruption in the circular palisade ditch, which could confirm the existence of an entrance, i.e., a passage, clearly bordered by an earthen rampart. In the central part of the circular fortification a deep shaft/well was discovered, which has been explored to the level of underground water. Apart from traces of smaller hearths on the inside of the palisade ditch and several deeply buried conical pits, with traces of charred, vertically placed posts, there are no other architectural remains inside the circular fortification. Traces of a catastrophic fire have been discovered inside the entire fortification and are especially visible above the palisade ditch. According to numerous sherds of secondarily burned ceramic vessels, the circular enclosure in Desić belongs to the post-Vinča culture of the Early Copper Age. According to the shape and basic elements of architecture, we assume that the earthen fortification in Desić belongs to a special form of smaller prehistoric enclosures, characteristic of circular palisade fortifications in the area of the Upper Tisza region, in the north-eastern parts of the Great Hungarian Plain.

The article deals with the problematic issues of tracing and dating the fortifications of the city of Bolgar in pre-Mongol times (from the end of the 9th to the beginning of the 13th centuries). On the basis of topographic referencing of the excavations, in which the filled ditches were discovered, all the data available on the placement of the defense lines of the early Bolgar are systematized. There is not enough data to exactly date them, therefore, the sequence of appearance of these lines is not obvious. The ditches indicate that there were ramparts next to them, the earth of which was used for the subsequent filling of ditches. Interesting tracks, on which, immediately after filling the earlier ditch, a new one was pulled out, with an indent to the outside. The task of new studies of the early fortifications of Bolgar will be to clarify the dates of their creation and spatial distribution.

Hillforts are fortified archaeological sites built from the Neolithic to Early Middle Ages within the area of Europe. They were usually surrounded by fortifications consisting of various combinations of ramparts and ditches, which today constitute their most striking remains. Although magnetometry surveys are commonly used for spatial identification of ramparts and ditches, a different method must be employed for directly obtaining depth information. Hence, we evaluate the potential of electrical resistivity tomography (ERT) for surveying hillfort fortifications. Within three hillforts of different ages in the Czech Republic, we investigated various features affecting the imaging ability of ERT, including bedrock type, building material, present‐day condition of fortification, impact of past or recent agricultural activities, and field settings of the ERT method. Supported by additional information from magnetometry and electromagnetic surveys, the results show that ERT is most applicable in cases of stony ramparts, ditches carved into rocky bedrock or well‐preserved earthen ramparts. Poorer results were achieved upon active and/or recently active agricultural lands, where fortifications have been gradually destroyed by ploughing. The remains of stony ramparts remained distinguishable in the latter case, but mere traces of earthen ramparts and ditches were invisible to ERT due to mixing of fortification material with on‐site soil. ERT is a unique method for detailed investigation of both ramparts and ditches by which a structure and its extent can be evaluated to indicate the function of a settlement and obtain information about former environmental conditions, population, land use and/or human–environmental interaction. [ABSTRACT FROM AUTHOR]

Observed changes in hydrological conditions indicate the need for economical use of water. This pertains to water management on a national scale, river basins and drainage systems. The outflow of water can be extensively regulated after various forms of retention in the catchment. The water level regulators presented herein enable the damming of water in drainage networks and the adjacent ground. Their advantages include their simple structure and operation principles and also the ability to adapt to currently existing devices in sub-irrigation systems. Laboratory tests were conducted to determine the hydraulic characteristics and operating conditions of three innovative regulator solutions. They focused on changing water damming heights by the closure of successively placed beams in order to obtain the required water level in the given hydrometeorological conditions. The structures of the regulators were made of plastics and rectilinear fillings for securing S-type excavations and elements of sheet piling with a developed shape in the plan of U and Z types, offering advantages compared to traditional materials (with respect to installation, operation and durability). All tested regulators were characterized by the effective flow Qe, caused by water leaks due to the lack of tightness of the regulator elements. The regulator with rectilinear beams of S-type closures offered the highest effective flow, which was 4 ÷ 5 times higher than in other regulators. U- and Z-type regulators were better at facilitating the regulation of the water table and the flow than the S rectilinear regulator. This led to both: the greater tightness of connections and the use of an overflow with a developed crest in the plan. The U and Z controllers had the highest hydraulic efficiency, expressed as the flow increase coefficient, at overflow layer heights of up to 5.0 cm. For tested fillings larger than 5.0 cm, U-type beams with a cylindrical corner shape had a lower flow increase coefficient (kq = 1.25) than Z-type beams with an angular corner shape, for which kq ∈ <1.35 ÷ 1.38>. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop a method for identification of the drainage ditch network, which can be used for surface runoff modeling and to increase accuracy of estimation of greenhouse gas (GHG) emissions in croplands and grasslands, using remote sensing data. The study area consists of 11 objects throughout Latvia with a total area of 145 km². Digital elevation models (DEMs) in two resolutions, which were created using three different interpolation methods, were used for the analysis. Several multi-level data filtering methods were applied to identify ditch network, including flow patterns, which can be used in surface runoff process. The method we developed correctly identified 85–89% of ditches, depending on the DEM used, in comparison to the reference data. Mapped ditches are located within 3 m range of the reference data in 89–93% of cases. The elaborated model is robust and uses openly available source data and can be used for large scale ditch mapping with sufficient accuracy necessary for hydrological modelling and GHG accounting in the national inventories. [ABSTRACT FROM AUTHOR]

In central Argentina, agro‐ecosystems constitute the dominant landscape, representing the replacement of extensive grassland areas by crops and pastures. Agriculture has caused the loss of extensive areas of Pampean inland wetlands through drainage and the construction of artificial aquatic habitats such as ditches and ponds.This study evaluated the availability and amphibian breeding use of 194 natural and artificial open water habitats and identified those attributes that affect amphibian diversity (richness, abundance and species occurrence).Interviews with farmers revealed that all artificial ditches, drainage channels and ponds were constructed directly or indirectly to support agricultural activities, and 61.5% of them were created at the expense of natural wetlands. The results from generalized linear mixed models) indicated a significant decrease (P < 0.05) in amphibian richness (14.2–35.7%) and abundance (35.3–86.6%) in artificial habitats compared with natural habitats.Overall, vegetation cover, average depth and edge slope emerged as the most important attributes affecting amphibian diversity in artificial open water habitats. Vegetation cover had a significant (P < 0.05) positive influence on species richness and abundance, whereas average depth and edge slope had the opposite effect.Given the substantial modification of inland wetlands in central Argentina, natural aquatic habitats should be considered top priorities for conservation, and law enforcement is urgently needed to control the drainage and levelling of lagoons, ponds and low‐lying areas. The appropriate design and planning of constructed wetlands, including shallow depth and slightly sloping edges, could greatly improve the ability of artificial wetlands to favour native amphibians in these altered landscapes.Artificial wetlands could offer complementary habitats to natural habitats for amphibians and aquatic wildlife if actions leading to sustainable management and territorial planning are applied. [ABSTRACT FROM AUTHOR]

Economical management of water resources involves water management on a national scale, including river basins and catchment areas, as well as on the scale of drainage systems. One of the devices for controlling the outflow of groundwater from a network of ditches is a flow regulator. In this work, three flow regulators were studied for their water damming capacity in the drainage network and the adjacent ground with the aim of determining their hydraulic characteristics and operating conditions. The adjustment consisted of changing the closing height in order to obtain the required damming level in a ditch. All three tested regulators were characterized by the presence of effective flow Qe, the value of which was determined for different damming levels. Water leaks occurred mainly in places where the damming elements were embedded in vertical guides and, to a lesser extent, at the horizontal joints of successively placed beams. The impact of the overflow shape and the development of the crest line on the obtained flow rate increase was different for the tested S, U, and Z models. The expansion coefficient of the overflow crest equaled kr = 1.0 for the rectilinear S regulator, kr = 1.58 for the labyrinth U regulator, and kr = 1.74 for the compound Z regulator. For the S4 variant, the modular total flow factor reached kQ = 1.19 for the elevation of the upper water above the overflow H = 14.9 cm. The U2 variant was characterized by a modular flow coefficient of kQ = 1.48 for H = 10.7 cm. For the Z1 variant with a cylindrical corner shape, the modular flow coefficient value was kQ = 1.60 for H = 8.2 cm in elevation. For the Z2 variant with an angular corner shape, kQ = 1.63 for H = 8.4 cm. [ABSTRACT FROM AUTHOR]

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Inland waters play an active role in the global carbon cycle and emit large volumes of the greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2). A considerable body of research has improved emissions estimates from lakes, reservoirs and rivers but recent attention has been drawn to the importance of small, artificial waterbodies as poorly quantified but potentially important emission hotspots. Of particular interest are emissions from drainage ditches and constructed ponds. These waterbody types are prevalent in many landscapes and their cumulative surface areas can be substantial. Furthermore, GHG emissions from constructed waterbodies are anthropogenic in origin and form part of national emissions reporting, whereas emissions from natural waterbodies do not (according to Intergovernmental Panel on Climate Change guidelines). Here, we present GHG data from two complementary studies covering a range of land uses. In the first, we measured emissions from nine ponds and seven ditches over a full year. Annual emissions varied considerably: 0.1–44.3 g CH4 m−2 year−1 and −36–4421 g CO2 m−2 year−1. In the second, we measured GHG concentrations in 96 ponds and 64 ditches across seven countries, covering subtropical, temperate and sub‐arctic biomes. When CH4 emissions were converted to CO2 equivalents, 93% of waterbodies were GHG sources. In both studies, GHGs were positively related to nutrient status (C, N, P), and pond GHG concentrations were highest in smallest waterbodies. Ditch and pond emissions were larger per unit area when compared to equivalent natural systems (streams, natural ponds). We show that GHG emissions from natural systems should not be used as proxies for those from artificial waterbodies, and that artificial waterbodies have the potential to make a substantial but largely unquantified contribution to emissions from the Agriculture, Forestry and Other Land Use sector, and the global carbon cycle. [ABSTRACT FROM AUTHOR]

Generalized solution of linearized Boussinesq equation is derived to approximate the nature of ground water flow due to changes in water levels in two ditches bounding an unconfined aquifer. In this research a mathematical model is developed for two flows. In the first case, a sudden change in the water level occurs in the two bounding ditches simultaneously, while in the second case, a sudden change in water level in one ditch is followed by a gradual rise in water level in the other ditch. Closed form analytical solutions are obtained for the two cases by solving governing equations using eigen value eigen function method. A numerical example problem is presented in which head values are computed at various places in the aquifer at given time intervals and the results plotted. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Observed changes in hydrological conditions indicate the need for economical use of water. This pertains to water management on a national scale, river basins and drainage systems. The outflow of water can be extensively regulated after various forms of retention in the catchment. The water level regulators presented herein enable the damming of water in drainage networks and the adjacent ground. Their advantages include their simple structure and operation principles and also the ability to adapt to currently existing devices in sub-irrigation systems. Laboratory tests were conducted to determine the hydraulic characteristics and operating conditions of three innovative regulator solutions. They focused on changing water damming heights by the closure of successively placed beams in order to obtain the required water level in the given hydrometeorological conditions. The structures of the regulators were made of plastics and rectilinear fillings for securing S-type excavations and elements of sheet piling with a developed shape in the plan of U and Z types, offering advantages compared to traditional materials (with respect to installation, operation and durability). All tested regulators were characterized by the effective flow Qe, caused by water leaks due to the lack of tightness of the regulator elements. The regulator with rectilinear beams of S-type closures offered the highest effective flow, which was 4 ÷ 5 times higher than in other regulators. U- and Z-type regulators were better at facilitating the regulation of the water table and the flow than the S rectilinear regulator. This led to both: the greater tightness of connections and the use of an overflow with a developed crest in the plan. The U and Z controllers had the highest hydraulic efficiency, expressed as the flow increase coefficient, at overflow layer heights of up to 5.0 cm. For tested fillings larger than 5.0 cm, U-type beams with a cylindrical corner shape had a lower flow increase coefficient (kq = 1.25) than Z-type beams with an angular corner shape, for which kq ∈ .

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Abstract Fertilization studies have elucidated basic principles of the role of nutrients in shaping plant communities and demonstrated the potential effects of anthropogenic nutrient deposition. Yet less is known about how these effects are mediated by interacting ecological factors, particularly in nutrient‐poor wetland habitats. In a long‐term experiment in a coastal plain wetland, we examined how fertilization and mowing affected the diversity and composition of a plant community as it reestablished after major disturbance. A drainage ditch in proximity to the experimental plots allowed us also to consider the influence of hydrology and its interactions with nutrient addition. Fertilization decreased species richness, with wetland specialist species showing especially great losses, and several lines of evidence suggest that the effect was mediated by competition for light. Altered hydrology via ditch drainage had effects that were similar to fertilization, with more rapidly draining plots showing lower diversity and decreased abundance of wetland species. Plant community diversity and dynamics were influenced by complex interactions between fertilization, disturbance, and hydrology. The negative effect of fertilization on species richness was initially mitigated by mowing, but in later years was more evident in mowed than in unmowed plots. In the absence of disturbance, nutrient addition increased the rate of transition to primarily woody communities. Similarly, drained plots experienced increased rates of succession compared to wetter plots. Our results suggest that these interactions need to be considered to understand the potential effects of anthropogenic nutrient addition and hydrologic alterations to wetland ecosystems.

Fertilization studies have elucidated basic principles of the role of nutrients in shaping plant communities and demonstrated the potential effects of anthropogenic nutrient deposition. Yet less is known about how these effects are mediated by interacting ecological factors, particularly in nutrient‐poor wetland habitats. In a long‐term experiment in a coastal plain wetland, we examined how fertilization and mowing affected the diversity and composition of a plant community as it reestablished after major disturbance. A drainage ditch in proximity to the experimental plots allowed us also to consider the influence of hydrology and its interactions with nutrient addition. Fertilization decreased species richness, with wetland specialist species showing especially great losses, and several lines of evidence suggest that the effect was mediated by competition for light. Altered hydrology via ditch drainage had effects that were similar to fertilization, with more rapidly draining plots showing lower diversity and decreased abundance of wetland species. Plant community diversity and dynamics were influenced by complex interactions between fertilization, disturbance, and hydrology. The negative effect of fertilization on species richness was initially mitigated by mowing, but in later years was more evident in mowed than in unmowed plots. In the absence of disturbance, nutrient addition increased the rate of transition to primarily woody communities. Similarly, drained plots experienced increased rates of succession compared to wetter plots. Our results suggest that these interactions need to be considered to understand the potential effects of anthropogenic nutrient addition and hydrologic alterations to wetland ecosystems. [ABSTRACT FROM AUTHOR]

The adverse effect of using traditional equipment particularly in developing countries is that it is time and energy consuming, less productive, difficult and more manpower is required. Hence, it is necessary to design and produce low price, and simple machines that can narrow this gap. The objective of the project reported in this article is to design and model a light duty trencher that is used for trenching the ground or soil for making ditch, and used for agricultural, ground cabling, ground piping and drainage system. The designed machine trenches, maximum of 1 m depth, 30 cm width and has adjustable length. The working mechanism is fully hydraulic, and equipped with an engine of 12.7 hp, which provides suitable power for the pump that delivers 23 l/min at 1500 rpm to drive hydraulic motors and actuators.

Vegetation living in agricultural channels (drainage ditches or irrigation channels) supports ecosystem functions such as water flow regulation; retention of sediments, agricultural pollutants and plant propagules; and bank strengthening. The review focuses on plant community functional parameters (aggregations of plant functional traits) and community properties that need to be considered to study the dynamics of these ecosystem functions, to support further modeling work on the functioning of these semiaquatic ecosystems. It also provides an up-to-date overview of the effects of channel management practices on vegetation, because these practices are a potential lever with which to drive plant community functional parameters and properties and, in turn, ecosystem functions. The review points out that the mean height, density, and flexibility of the plant cover, sometimes integrated in the "blockage factor", mainly influence the average components of the water flow associated with the functions of water regulation, and retention of sediments and non-floating propagules. The density of plants, or area of the plant cover at the water surface, are generally used to explain floating propagule retention. The biomasses of living and dead vegetation are the properties used to assess the retention of agricultural pollutants. Root density and root length density, as well as tensile strength of the root system, are parameters generally associated with bank strengthening. Regarding the effects of channel management practices, this work highlights that research generally has focused on the resulting plant richness and diversity, but has not provided much information on associated plant community functional parameters and properties. [ABSTRACT FROM AUTHOR]

Most tropical islands have limited water supply due to the small size of their watersheds and aquifers, unique geology, and distribution of rainfall; each affecting the reliability of water resources for meeting agricultural needs. To improve water supply, reservoirs provide critical storage of surface water. However, climate-driven shifts in the distribution, intensity, and amount of rainfall will alter runoff that feeds reservoirs. Mass-balance modeling was used to evaluate the effects of various management constraints on water availability for the Wahiawā Reservoir (O'ahu, Hawai'i) as well as the impact of 20% less dry season rainfall and stream flow to assess the effect of projected climate change on maintaining: (1) a minimum downstream flow; (2) a minimum agricultural supply; (3) a minimum and maximum reservoir level; and (4) a combination of minimum downstream flow and minimum agricultural supply. Under current climate conditions, maintaining a minimal downstream water release could be met with minimal consequences for agricultural supply and reservoir level. However, both agricultural supply and downstream flow had to be reduced during dry periods to keep the reservoir level above a minimum level. Maintaining a minimum downstream flow resulted in a 4.2% reduction in mean agricultural supply and 2.2% reduction in mean reservoir elevation compared to baseline conditions. By contrast, a 20% reduction in dry season water inputs resulted in a 17.8% reduction in mean agricultural supply in the minimum downstream flow scenario compared to current rainfall conditions. Furthermore, the number of days the reservoir level dropped below the minimum needed for a fishery increased (range 1.15–25×) across scenarios compared to baseline. Successful management of surface water within a social-ecological system will be challenged by the increasing unpredictability of rainfall. [ABSTRACT FROM AUTHOR]

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In the scientific literature, 13 hillforts of Transcarpathia are referred to the Hallstatt period, of which only five are credible: Shelestovo, Ardanovo, Irshava, Bila Tserkva, and Seredne Vodyane. With the exception of Seredne Vodyane, which is of particular interest in terms of studying the early stage of the settlement of the mountain zone of the region, they are all located on the hills in the foothill zone. By the area, the fortified points are divided into sites of medium size (2-10 hectares): Shelestovo, Ardanovo, and Irshava and small ones (up to 2 hectares): Bila Tserkva and Seredne Vodyane. Fortifications are represented by ramparts and ditches. The ramparts reach a height of 2-3 m with a base width of 6-10 m, and ditches reach a depth of 1.5-2 m and a width of 5 m and more. In some cases, there is no rampart in the hard-to-reach places (Bila Tserkva), and additional lines of fortifications were erected in easily accessible places (Irshava). According to the structure of the embankment, the ramparts are divided into earthen and stone-earth. Sometimes for the strengthening of ramparts, stacked structures of logs (Irshava) or stone walls of dry masonry (Shelestovo) were used. Among the structures on the crest of a rampart, we note the palisades detected by the pits in Ardanovo. In the course of the small-scale excavations of the hillforts, the presence of a very weak cultural layer and the almost complete absence of economic structures were observed that, before carrying out large-scale works and obtaining materials that disprove these data, allows classifying these sites as shelters. It should be noted that, in Shelestovo, Ardanovo and Irshava, a relatively large amount of ceramic material was found directly in the embankments of the shafts, which indicates that the fortifications were created already after the settlements began functioning on the mountain tops.

Rockfall ditches or areas can be constructed in order to protect against rockfalls in settlements that are in danger of rockfalls when the population density is not high. Nevertheless, in the design of such protection structures, essential site-specific engineering studies and analyzes are often not carried out appropriately. Therefore, rockfall ditches are occasionally not capable of preventing rockfalls. Within the scope of this study, the performance of a 2 m-deep and 1 km-long rockfall ditch excavated at the upper elevation of touristic Akköy (Ürgüp) settlement in 2012 in order to prevent the entrance of falling rocks to the residential area was evaluated on the basis of 3-dimensional rockfall analyses. According to the rockfall risk classification, the settlement is under moderate rockfall risk. The digital surface model used in 3-dimensional rockfall analyses was generated by point cloud data obtained from photogrammetric images taken by unmanned aerial vehicle. During field observations, it was determined that the dimension of the previously fallen ignimbrite blocks could reach up to 2 m. On the other hand, the high persistency of discontinuities in the source zone indicates that the dimensions of the potential rockfall blocks may be large. As a result of the 3-dimensional rockfall analyses carried out in RocPro3D software, it was defined that the falling blocks are generally caught by the ditch excavated between the source zone and the settlement, but in some sections of the ditch those blocks may continue to roll over the rockfall ditch. Eventually, Akköy settlement is still partially under the danger of rockfalls. If the rockfall ditch is not periodically cleaned in the course of time, the extent of danger will enlarge with the decrease in the capacity of the trench. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Polonorum. Formatio Circumiectus is the property of Wydawnictwo Uniwersytetu Rolniczego im. Hugona Kollataja w Krakowie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)