Erosion Control Works Research Articles

Afforestation of arid and semiarid ecosystems in Turkey

Sustainable management of arid and semiarid forests requires careful planning and implementation. Afforestation by planting and seeding is a fundamental tool for the establishment of new forests on barren landscapes and restoration of degraded forests in arid and semiarid ecosystems. In afforestation efforts, the consideration of site preparation, selection of species, seed source, and planting methods pose a number of ecological and economic challenges. Possessing one of the world's richest floras, Turkey suffered from heavy degradation during the last millennia. Some studies suggested that forests and steppes once covered 60%-70% and 10%-15% of the Anatolian landscape, respectively. Growing population, overgrazing, clearance for agriculture, fires, excessive timber harvesting, and misuse of lands led to a 26% reduction in the forest area. The Turkish Forest Service completed 2.3 million ha of afforestation and 1.2 ha of erosion control works, mostly in semiarid landscapes. This article presents an assessment of afforestation activities in the semiarid and arid regions of Turkey and is a review of the efforts exerted during the period 1945 to 2014.

Analysis of Forest Environmental Factors on Torrent Erosion control work area in Gyeongsangnam-do

Analysis of Forest Environmental Factors on Torrent Erosion control work area in Gyeongsangnam-do

THE RUNOFF’S BEHAVIOR TO DIFFERENT LAND USES IN WATERSHEDS AT NORTHWESTERN PARANA, BRAZIL

The study attempted to evaluate the effectiveness of the forestry ecosystem on the maintenance of the hydrological processes, which participated on soil’s erosion. Aimed to support the land use planning and soil’s erosion control works. The work was done through of a simulated rainfall experiment replicated on three watersheds of the Northwest region of the State of Paraná, into four land uses. The experiment was developed by comparing the runoff’s behavior of the land uses: forest and three agricultural crops (coffee, cassava and pasture). The results showed greatest infiltration coefficient for soils under forest, with significant difference to other land uses studied. These differences showed that unit area with forest cover resulted in 9,71 times less runoff than area with pasture, 7,86 times less runoff than area with coffee, and 5,56 times less runoff than area with cassava. The results show the forest’s potentiality to improve the infiltration processes, showing responses that virtually are not possible to be superseded by the management practices adopted on the other cropping systems studied. The study, to define the range of the forest’s effect on its environment, is characterized as essential to planning of the forest cover regarding to size area, and spatial distribution.

Experimental evidences and numerical modelling of runoff and soil erosion in flume tests

Rainfall causes runoff and soil erosion in artificial and natural slopes and important insight may derive from quantitative physically-based models or laboratory tests. Measurements of runoff and sediment discharges in small-scale experimental flume tests have become popular in recent years and a wide range of slope angles, soil grain-size-distributions and rainfall characteristics has been tested so far. In the literature, there are numerous studies dealing with a comparison between experimental data and model predictions using appropriate assumptions. However, there are still scientific gaps under complex experimental circumstances. The main goal is to discuss the performance of a physically-based numerical model in simulating well-documented runoff–erosion laboratory flume tests, also highlighting the uncertainties one may expect for real cases when applying numerical modelling of runoff and soil erosion to a real catchment.The paper deals with the numerical analysis of four experimental flume tests available in the literature, which investigate the erosion of bare gentle slopes due to constant-intensity rainfall; the behaviour of a steeper slope, bare or vegetated, under constant rainfall larger than in the previous experiments; the role of a sequence of different rainfall intensities (with the same cumulated rainfall), and different surface roughness in gentle slopes. Those experimental tests were simulated through LISEM, and the numerical results reproduce satisfactorily the global behaviour of the experimental plots eroded by artificial rainfall in all the four flume tests. As far as the ratio of the observed to the predicted peaks of water discharge and sediment concentration, the simulated peaks are very close to those observed in the laboratory experiments, except for low slope angle conditions where water discharge peak is overestimated and for one flume where sediment concentration peak is underestimated in two out of three cases. This analysis highlights that LISEM allows reasonably estimating the peak values of water and sediment discharge, which are generally used as design parameters of erosion control works. With reference to peak times of water discharge and sediment concentration, this paper highlights that LISEM has limitations in properly assessing the peak times of water discharge and sediment concentration; better results are, instead, expected when LISEM is used to simulate erosion and runoff on vegetated slopes. Globally, the results allow the assessment of the overall performance of the selected erosion model to correctly interpret the experimental evidences. As well, the discrepancies among the laboratory evidences and numerical results are discussed in relation to slope geometry and soil properties.

Changes in the hydrological status of the basin due to the application of erosion control works

Protection of land with vegetation is the primary factor in the fight against water erosion with necessary application of biotechnical, technical, administrative and planning measures. One of the first basins to be treated with works for the protection against erosion and torrent control is the Gradasnica River basin. The basic parameters to display the changes of the hydrological status of the land are the state of erosion, the change of erosion-coefficient, annual sediment yield, specific annual sediment discharge through the hydrographic network, the value of the runoff curve number and value of the maximal discharge. Works on protection from erosion and regulations of torrents have influenced the decrease in erosion coefficient values from strong erosion (Z=0.99) to the value of weak erosion (Z=0.40), as well as the reduction of the maximum discharge value from Qmax(1956)=108,12m3/s to the value of Qmax(2014)=87.2 m3/s.

Applied Hydrotechnical Measures in Sustainable Land Management, Case Study: Timis County, Romania

Sustainable land management (SLM) refers to practices and technologies that aim to integrate the management of land, water, biodiversity, and other environmental resources to meet human needs while ensuring the long-term sustainability of ecosystem services and livelihoods. According to Romanian scientific methodology, hydrotechnical measures also include land reclamation and improvement systems as irrigation, land drainage and soil erosion control works. The integration of land reclamation works in sustainable land management represents a new scientific approach especially regarding the problem from the point of view of ecosystem services provided by these works. This type of approach will overrun the interdisciplinary borders and will assume o stronger cooperation from planning to implementation. This paper will debate the feasibility and opportunity of integrating applied hydrotechnical measures like irrigation and drainage works in the frame of sustainable land management.

수량화II 분석을 이용한 사방지 유지/해제 기준인자 선정

An erosion control district should be designated to perform erosion control works. After such designation, an owner of the concernedland needs to obtain a permission to perform any development activities. To relieve the concerned area from such erosion control dis-trict, it should be judged that the concerned area has achieved an intended purpose of the designation after 10 years of such des-ignation. This study was carried out to develop a reasonable basis to determine whether or not such designation should be maintainedor terminated. Case study and quantification analysis were carried out to identify factors that influence such designation maintenanceand termination and develop a judgement table. The factors identified in this study included the status of erosion control structures,coverage of grass, occurrence of soil erosion (Y/N), the status of downstream, growth status of planted trees and stability of othergreening facilities. The judgement table was developed by giving weight to the factors based on the quantification analysis. It showeda high accuracy rate of 96.8% and correlation ratio of 0.61. This will serve as a basis to judge proper the designation duration of ero-sion control district.Key words : Erosion Control District, Evaluation Criteria, Intended Purpose, Quantification II Analysis

Evaluation of the post-fire erosion and flood control works in the area of Cassandra (Chalkidiki, North Greece)

We quantified morphological and hydrographical characteristics of two drainage basins (Chanioti and N. Skioni) on Cassandra peninsula of Chalkidiki (North Greece), and evaluated the effectiveness of post-fire flood and erosion control works. The drainage basins were chosen because of their severe damage by fire, post-fire potential for erosion and flood due to the steep relief, and the importance of the area for residential and tourism development. The first measures taken in the area after the fire were salvage cutting of burned trees, a total ban on grazing, and construction of three types of works, log erosion barriers (LEBs), log check dams and contour branch barriers. Almost all necessary post-fire works were completed in both catchments but many construction failures were recorded. Approximately 75 % of the LEBs and 45 % of the contour branch barriers functioned properly, while the remainder failed. Nearly 80 % of the log dams were sedimented to 0–20 % of the dam height, 14.3 % were 20–40 % filled and 5.9 % collapsed. Despite these failures, peak discharge declined by 10.5 % in Chanioti and 20.4 % in N. Skioni catchment. The main reasons for works failures were the rush of construction and the limited supervision of workers, which resulted in floods during the years that followed.

Economic erosion control works in old Tamano experiment, Okayama prefecture

Economic erosion control works in old Tamano experiment, Okayama prefecture

Erosion protection as a precondition of ski resorts development on the Old mountain

The environmental impacts in Serbian ski areas are very strong, leading to landscape degradation, functionality and financial losses, which is illustrated in ski-resort 'Stara planina'. Construction or improvment works cause hard destruction of topsoil and native vegetation. Some activities enhance erosion production and sediment yield: clear cuttings; trunk transport down the slope; road construction and large excavations. Also, lack of erosion control works in ski areas, especially between April and October, result in various forms of land degradation such as furrows, gullies, landslides, or debris from rock weathering. Planning and designing activities, with application of technical and biotechnical erosion control structures, through concept of restoration, are necessary measures in protection of ski areas.

Evaluation of the post-fire erosion and flood control works in the area of Cassandra (Chalkidiki, North Greece)

Evaluation of the post-fire erosion and flood control works in the area of Cassandra (Chalkidiki, North Greece)

The Impacts of Rural Population Changeson Forests and Forestry (A Case Study in Trabzon)

Migration rural to urban, accelerated in the last quarter of the twentieth century, caused a decline in the population of the village. Demographic and socio-economic structure of the population has changed by the process of this development. Trabzon also has been affected by this process. This study prepared on the basis of data from the province of Trabzon aims to reveal how forests and forestry has effected by population changes in rural. This study has prepared on the basis of the data obtained from various written sources and records and the original data collected from the field. The original data obtained from semi-structured interviews with chief foresters, surveys applied to 848 people exemplified with the 95% confidence level and 5% margin of error in 68 villages from 211forest villages, Trabzon. The findings obtained from the survey results examined by percentage values and the frequency distributions, The decrease in village population and the number of families spent the winter season in village is because of the migration. Thus, this decrease has reduced pressure on forest resources. It was voiced concerns that reduction of the population in forest villages can make more difficult providing local labor for cerequired for forestry activities carried out in this villages in the past. At this point contracting the afforestation and erosion control work to private entrepreneurs, expansion of stumpage sales practices in production are developments that addressed these concerns. Increase inper capita income inforest villages has reduced the dependence on forest resources, especially fire wood. Reduce dependence on forest resources and the concept which is aware of the environmental functions of forests has provided an easement to forest workers of the forestry department

Comparison of erosion and erosion control works in Macedonia, Serbia and Bulgaria

While soils are as essential to human society as air and water, soil degradation has not received nearly as much attention as the threats to these other elements. On the map of water erosion of Europe, Southern Europe is red “colored”. Erosion in the Balkan countries, through both on and offsite effects is a major cause of soil and water degradation.This paper compares erosion control works in several countries from the Balkan region (Macedonia, Serbia, and Bulgaria). The basis for comparative analyses was various country reports as well as available published papers. Quantitative method-text analyze method was used for these study.Natural conditions in the Balkan countries contribute to the appearance of various erosion forms and the intensity of the erosion processes. Over the history of these countries, people who settled this region used the available natural resources to fill their needs (tree cutting, incorrect plugging, overgrazing), which contributed to soil erosion. Organized erosion control works in the Balkans started in the beginning of the 20th century (1905 in Bulgaria). The highest intensity of erosion control works were carried out during the period 1945 – 1990. Various erosion control works were launched. Bulgaria had a large anti-erosion afforestation, almost 1 million ha. Bulgaria's ecological river restoration approach has been in use for almost 50 years. Serbia contributed significant erosion and torrent control works on hilly agricultural areas. Specific screen barrages and afforestation on extremely dry areas are characteristic in Macedonia. A common characteristic for all countries is a high decrease in erosion control works in the last 20 years.

Use of the 2-year, 6-hour rainfall in the design of erosion control works

The design of soil erosion control works often involves the use of the revised universal soil loss equation to estimate potential soil loss (Renard et al, 1991) and the rational method to estimate peak flows (eg. Landcom, 2004). Both these methods require the use of design rainfall intensities but for different purposes. This paper clarifies the use of design rainfall in these approaches, identifies where confusion may occur, and suggests an approach that is consistent with current engineering guidelines.

Use of the 2-year, 6-Hour Rainfall in the Design of Erosion Control Works

The design of soil erosion control works often involves the use of the revised universal soil loss equation to estimate potential soil loss (Renard et al, 1991) and the rational method to estimate peak flows (eg. Landcom, 2004). Both these methods require the use of design rainfall intensities but for different purposes. This paper clarif es the use of design rainfall in these approaches, identif es where confusion may occur, and suggests an approach that is consistent with current engineering guidelines.

Torrential floods and town and country planning in Serbia

Abstract. Torrential floods are the most frequent natural catastrophic events in Serbia, causing the loss of human lives and huge material damage, both in urban and rural areas. The analysis of the intra-annual distribution of maximal discharges aided in noticing that torrential floods have a seasonal character. The erosion and torrent control works (ETCWs) in Serbia began at the end of the 19th century. Effective protection from torrential floods encompasses biotechnical works on the slopes in the watershed and technical works on the torrent beds, within a precisely defined administrative and spatial framework in order to achieve maximal safety for people and their property. Cooperation to overcome the conflicts between the sectors of the water resources management, forestry, agriculture, energetics, environmental protection and local economic development groups is indispensable at the following levels: policy, spatial planning, practice, investments and education. The lowest and most effective level is through the Plans for Announcement of Erosive Regions (PAERs) and the Plans for Protection from Torrential Floods (PPTFs), with Hazard Zones (HZs) and Threatened Areas (TAs) mapping on the basis of the hydrologic, hydraulic and spatial analysis of the factors that are important for the formation of torrential floods. Solutions defined through PAERs and PPTFs have to be integrated into Spatial Plans at local and regional levels.

The implementing of some plant species in erosion control on slopes

With the need to conserve and improve the environment, it is recommended to employ plant materials in the erosion control of torrents and slopes alongside roads. Considering the well-known properties of some willow species regarding their power of vegetative reproduction, survival in poor soils and often flooded alluvium, we researched into the potentials of the following species: Salix triandra L., Salix purpurea L. and Salix incana Schrk. in the catchment of the warehouse 'Gvozdac', Experimental Estate Goc, Serbia. The research started in 2004 and has continued till the present day. The above-mentioned willow species showed significant efficiency in the bank protection of torrential watercourses and on the moist slopes of embankments and cuts of roads. Some of them can even stand a certain degree of aridity, while other species, on poor, eroded soil exposed to long and extreme drought, could not survive and did not show the expected effect, which is also the consequence of the absence of maintenance and adequate attention to such erosion-control works. In spite of the above, one of the willow species survived even in the most severe conditions, checking the erosion of the road cut slope and the road construction itself, and prevented the impacts of aggressive atmospheric waters, thus halting the erosion ridges and the removal of the asphalt road surface. The above facts prove that, with adequate measures of maintenance, plant materials can be very successfully applied for both longitudinal structures and to check dams in torrent control, as well as in erosion control on the slopes in catchments, both in civil engineering works and in forest exploitation. The research requires closer attention, extending the interests to some grass and shrub species, with the aim of ecological erosion control and reclamation of endangered watercourses, slopes and, in general, environmental protection and nature conservation. .

Redwoods, restoration, and implications for carbon budgets

The coast redwoods ( Sequoia sempervirens) of California have several unique characteristics that influence interactions between vegetation and geomorphic processes. Case studies, using a combination of in-channel wood surveys and an air photo inventory of landslides, illustrate current conditions in a redwood-dominated watershed undergoing restoration work, and the influence of wood loading and landslides on the carbon budget. Redwood trees have extremely large biomass (trunk wood volumes of 700 to 1000 m 3) and are very decay-resistant; consequently, they have a large and persistent influence on in-channel wood loading. Large wood surveys indicate high wood loading in streams in uncut forests (0.3–0.5 m 3/m 2 of channel), but also show that high wood loading can persist in logged basin with unlogged riparian buffers because of the slow decay of fallen redwoods. Through a watershed restoration program, Redwood National Park increases in-channel wood loading in low-order streams, but the effectiveness of this technique has not yet been tested by a large flood. Another unique characteristic of redwood is its ability to resprout from basal burls after cutting, so that root strength may not decline as sharply following logging as in other types of forests. An air photo inventory of landslides following a large storm in 1997 indicated: 1) that in the Redwood Creek watershed the volume of material displaced by landslides in harvested areas was not related to the time elapsed since logging, suggesting that the loss of root strength was not a decisive factor in landslide initiation, 2) landslide production on decommissioned logging roads was half that of untreated roads, and 3) landslides removed an estimated 28 Mg of organic carbon/km 2 from hillslopes. The carbon budget of a redwood-dominated catchment is dominated by the vegetative component, but is also influenced by the extent of mass movement, erosion control work, and in-channel storage of wood.

Use of gabions and vegetation in erosion-control works

Heavy winter and spring rainfall during the years 2005, -06, -07, and -08 brought about numerous torrential floods and landslides throughout the world and in Serbia. They endangered people, animals, settlements, fields, and roads. This reminded us of a readily available, cheap, and efficient material: stone in wire baskets of doubly galvanized wire of various sizes and forms - gabions - which are also long-lasting, flexible, and ecological. If made according to prescribed standards, they offer a permanent solution for many erosion-control problems. In addition, they can be used in urgent interventions to protect the lives of humans, animals, and plants and prevent of immense material losses. This paper calls attention to an unjustifiably neglected but important material, easily manipulated and with significant advantages compared to other structural materials, as well as to the possibility of its successful combination with vegetation, viz., willow (Salix sp.) cuttings and grasses.

Restoration of eroded surfaces in Serbian ski-areas

The environmental impacts in Serbian ski areas are very strong, leading to landscape degradation and functionality losses. Construction or improvement works cause serious destruction of topsoil and native vegetation. Some activities enhance erosion production and sediment yield: clear cuttings; trunk transport down the slope; road construction and large excavations. Also, lack of erosion control works in ski areas, especially between April and October, result in various forms of land degradation such as furrows, gullies, landslides, or debris from rock weathering. The consequences of mismanagement in ski areas are noticeable in downstream sections of river beds, causing floods and bed-load deposition. Planning and designing activities, with the application of technical and biotechnical erosion control structures, through the concept of restoration, are necessary measures in the protection of ski areas.