Changes In Land Use Types Research Articles

Land use and land cover change-induced changes of sediment connectivity and their effects on sediment yield in a catchment on the Loess Plateau in China

The spatial distribution of landscape pattern in catchments has a great impact on the potential sediment detachment and transport capacity. In this study, a sediment connectivity model was applied to evaluate the effect of the spatial distribution of landscape pattern on the sediment transfer in a typical catchment on the Loess Plateau in China based on land use and topography data in 1964, 2004, and 2018. Thereupon, the impacts of changes in different land use types on sediment connectivity and those of sediment connectivity changes on sediment yield reduction in the catchment were quantified. The results showed that (i) grassland and slope farmland were the main land use types in the catchment, and a decrease of the slope farmland area and an increase of the vegetation coverage occurred from 1964 to 2018; (ii) compared with 1964, most parts of the catchment in 2004 and 2018 had an overall lower connectivity index (IC); (iii) the distribution of sediment connectivity presented obvious spatial variability. The hill slopes and tributary gullies tended to be relatively well connected, and the main gully was highly disconnected. Scenario simulations showed that the potential sediment reduction effect was 20%−45% for vegetation, and <10% for terraces or dam lands in 1964, 2004, and 2018. The effect of impounding sediment by check dams was not included in IC calculation in this study, and it was found that the sediment impounded by these dams accounted for about 16% of sediment discharge reduction during 1995–2004 and 1% during 2005–2018. The IC reduction was responsible for 84% of the decrease of sediment discharge during 1995–2004 and 99% during 2005–2018, reflecting that vegetation restoration and terrace construction on slopes has become the main drivers for reducing IC value and sediment yield.

Changes of vegetation coverage in Beijing in the background of urbanization based on the data from 2000 to 2019

With the rapid development of urbanization, high-intensity human activities in Beijing profoundly impact the changes of ecological environment, especially on vegetation coverage. Vegetation can provide a variety of ecological services for the city. Based on the data of NDVI (Normalized vegetation Index) from 2000 to 2019, the study analysed the Spatio-temporal changes of vegetation variation and land use pattern in Beijing by GIS analysis. The proportion of the significantly increased pixels of NDVI occupied 76.71% while that of the significantly decreased pixels only occupied 4.99% of the total. The significant positive trends of NDVI were concentrated in the urban core functional areas within the Fifth Ring Road and in the northern and western mountainous areas. The significant negative trends of NDVI were concentrated from the 5th Ring Road to the outside areas of the 6th Ring Road. And the gradual change of land use type is a prominent feature in significantly positive trend area. The reflection of the vegetation coverage and land use change on a large time scale in Beijing has a certain reference value for future land pattern planning and urban policy revision.

Kajian Faktor Penyebab Banjir dalam Perspektif Wilayah Sungai: Pembelajaran Dari Sub Sistem Drainase Sungai Beringin

Urbanization causes a shift in human activities and increases the occupancy of open spaces in the hilly areas of Semarang City. As a strategic area in the city of Semarang, Mijen and Ngaliyan Districts, which are the upstream and transition areas of the Beringin Drainage Sub-System, are experiencing economic and social growth. This then has an impact on the intensity of the floods that occur in Tugu District as its downstream area. This study aims to analyze the factors that cause flooding in the area of the Beringin Drainage Sub-System from a theoretical review to validate the results through interviews and field surveys. This study uses a qualitative descriptive analysis method by examining documents, research journals, books and maps and other related documents. From the results of the study, it can be concluded that the factors causing floods in the Beringin Drainage Sub-System area include changes in land use, rainfall and soil types, slope levels, erosion and sedimentation and inadequate capacity of the drainage system are phenomena and processes that are interrelated with one another. Strategic efforts are needed to anticipate flood events that occur almost annually in the Beringin Drainage Sub-System area.

The Importance of Environmental Factors for the Development of Water Erosion of Soil in Agricultural Land: The Southern Part of Hronská Pahorkatina Hill Land, Slovakia

The water erosion research was carried out in the lowland type of hilly landscape. The aim was to monitor and evaluate the importance of environmental factors (steepness of slope, relief shapes, aspect, slope length, combination slope length (L) and slope (S)—LS factor, types of land use changes) for the development of water erosion. We focused on the identification of areas threatened by erosion by interpreting aerial photographs from several time periods. This was followed by verification of erosion using soil probes. We identified 408.44 ha of areas affected by erosion, and measured the depth of soil and “A” horizons thickness. The environmental factors were modeled in geographical information systems by tools for spatially oriented data. Subsequently, the influence and significance of individual environmental factors were compared, and the probability of erosion was statistically estimated. The decisive factors in the formation of erosive surfaces are the LS factor and the slope. We also consider the factor of the relief shape to be important. The shape did not appear to be very significant as a separately evaluated factor, but all convex parts correlate with the identified erosion surfaces. The susceptibility of erosion related to the aspect of the slopes to the cardinal directions has not been confirmed. Types of land use changes with the most significant relation of erosion were confirmed in areas of strong intensification. We confirmed the importance of factors and land use for the development of erosion processes.

Spatial interaction between urbanization and ecosystem services in Chinese urban agglomerations

Urbanization leads to significant changes in land-use types and affects various ecosystem services. While previous studies have analyzed the interaction between urbanization and ecosystem services at the national, provincial, and city scales, there is insufficient information on the spatial interaction between urbanization and ecosystem services in urban agglomerations for different development levels. To address these research gaps, this study used hot spot analysis and spatial autocorrelation models to measure the spatial interaction between urbanization and ecosystem services in China’s ten major urban agglomeration areas for the period 1995–2018. The results found that: (1) China’s urban agglomerations have experienced rapid urbanization, exhibiting a rising growth trend at all development levels of urbanization. Those grouped in the growing category exhibited the fastest growth, while those in the mature category posted the slowest growth. The spatial distributions of the urbanization indicators differ significantly. The population density showed a more pronounced clustering feature, while the proportion of urban land use was distributed mainly around the core cities. (2) Different ecosystem services exhibited varying change trends. Food supply increased significantly. Carbon storage decreased in all but two urban agglomerations (Beijing-Tianjin-Hebei and Sichuan-Chongqing). Habitat quality services also decreased in all agglomerations, except for the northern slope of the Tianshan Mountains. In terms of ecosystem service hot spots, there is distinct spatial heterogeneity. Food supply hot spots are concentrated in the plain areas, while habitat quality and carbon storage hot spots are mainly clustered in mountain and water regions. (3) Carbon storage and habitat quality are negatively correlated with the three indicators of urbanization, while food supply is positively correlated with population density and GDP density and negatively correlated with the proportion of urban land use. Urban land expansion is directly linked to the decline in ecosystem services, while population and economic growth have indirect effects. This study can contribute to understanding the correlation between urbanization and ecosystem services, and providing references for high-quality spatial development.

Invasive woody plants as foci of tick-borne pathogens: eastern redcedar in the southern Great Plains.

Habitat preference and usage by disease vectors are directly correlated with landscapes often undergoing anthropogenic environmental change. A predominant type of land use change occurring in the United States is the expansion of native and non-native woody plant species in grasslands, but little is known regarding the impact of this expansion on regional vector-borne disease transmission. In this study, we focused on the impact of expanding eastern redcedar (Juniperus virginiana; ERC) and tested two hypotheses involving relationships between habitat preferences of adult tick species in rural habitats in central Oklahoma. Using CO2 traps, we collected ticks from two densities of ERC and grassland and screened adult ticks for the presence of pathogen DNA. We found support for our first hypothesis with significantly more Amblyomma americanum (Linnaeus) and Dermacentor variabilis (Say) collected in ERC habitats than in grassland. Our second hypothesis was also supported, as Ehrlichia- and Rickettsia-infected A. americanum were significantly more likely to be collected from ERC habitats than grassland. As the first evidence that links woody plant encroachment with important tick-borne pathogens in the continental United States, these results have important ramifications involving human and companion animal risk for encountering pathogen-infected ticks in the southern Great Plains.

Comparative Analysis of the Factors Influencing Land Use Change for Emerging Industry and Traditional Industry: A Case Study of Shenzhen City, China

Analyzing the factors influencing emerging industry land use change is important for promoting industrial transformation and for upgrading and improving the level of intensive use of emerging industry land. In recent years, to solve the problem of land resource shortage and expansion space, Shenzhen has implemented a strategy of promoting urban development through technological innovation and has actively promoted the transformation of inefficient industrial land to emerging industry. This article introduces the development, land use types, and spatial distribution of Shenzhen’s emerging industries. Based on the logistic regression model, we analyze the differences between the factors influencing changes in land use for both emerging and traditional industry. The research results show that the distance from public roads, the distance from highways, the distance from railway freight stations, the proportion of secondary industry, and the proportion of tertiary industry are important explanatory variables for the two types of land use change. Traditional industrial land use is also affected by the land slope, the distance from ports, the population, and fixed asset investment. Emerging industry land use is also affected by the distance from the airport, the number of railway stations, the quality of the population, and innovation-driving forces. These results provide a reference for government to rationally plan emerging industry land and differentiated management of this, in order to fill the current research gap in the field of land use change, and to contribute to research revealing the mechanisms driving changes in emerging industrial land.

Land-use modifications and ecological implications over the past 160 years in the central Apennine mountains

ABSTRACT Today’s Mediterranean landscapes result from the interaction between ecosystems and anthropogenic activities. This study aims to assess how the land-use changes between the mid-nineteenth and end of the twentieth century influenced the temporal continuity of the ecosystems in central Apennines (central Italy). Information was acquired from Gregorian cadastral maps, orthophotos and aerial photos (1850, 1954, 1980 and 2010), digitised and georeferenced using QGIS 3.10.1 software. Marked changes in land-use types were found. From 1850 to 1954, grasslands were widely transformed into arable lands, but in the next 60 years they changed again into new grasslands and forests. Forests underwent a slow but continuous expansion from 1850 to 2010. Only a small percentage of the forest and grassland patches (14 and 16%, respectively) have seen ecological continuity. These considerations call attention to temporal continuity of ecosystems, together with the historical dynamism of landscapes, in defining land management and nature conservation policies.

Quantifying the Relative Contribution of Climate Change and Anthropogenic Activities on Runoff Variations in the Central Part of Tajikistan in Central Asia

Quantifying the relative contribution of climate change and anthropogenic activities to runoff alterations are essential for the sustainable management of water resources in Central Asian countries. In the Kofarnihon River Basin (KRB) in Central Asia, both changing climate conditions and anthropogenic activities are known to have caused changes to the hydrological cycle. Therefore, quantifying the net influence of anthropogenic contribution to the runoff changes is a challenge. This study applied the original and modified Mann–Kendall trend test, including the Sen’s slope test, Pettitt’s test, double cumulative curve, and elasticity methods. These methods were applied to determine the historical trends, magnitude changes and change points of the temperature, precipitation, potential evapotranspiration, and runoff from 1950 to 2016. In addition, the contributions of climate change and anthropogenic activities to runoff changes in the KRB were evaluated. The trend analysis showed a significant increasing trend in annual temperature and potential evapotranspiration, while the annual precipitation trend showed an insignificant decreasing trend during the 1950–2016 time period. The change point in runoff occurred in 1986 in the upstream region and 1991 in the downstream region. Further, the time series (1950–2016) is separated into the prior impacted period (1950–1986 and 1950–1991) and post impacted period (1987–2016 and 1992–2016) for the upstream and downstream regions, respectively. During the post impacted period, climate change and anthropogenic activities contributed to 87.96% and 12.04% in the upstream region and 7.53% and 92.47% in the downstream region of the KRB. The results showed that in runoff changes, the anthropogenic activities played a dominant role in the downstream (97.78%) and the climate change impacts played a dominant factor in the upstream region (87.96%). In the land-use type changes, the dominant role was played by construction land, which showed that the area from 248.63 km2 in 1990 increased to 685.45 km2 (175.69%) in 2015. These findings suggest that it is essential to adopt effective steps for the sustainable development of the ecological, hydrological, and social order in the KRB in Central Asia.

Changes in soil water holding capacity and water availability following vegetation restoration on the Chinese Loess Plateau

Changes in land use type can lead to variations in soil water characteristics. The objective of this study was to identify the responses of soil water holding capacity (SWHC) and soil water availability (SWA) to land use type (grassland, shrubland and forestland). The soil water characteristic curve describes the relationship between gravimetric water content and soil suction. We measured the soil water characteristic parameters representing SWHC and SWA, which we derived from soil water characteristic curves, in the 0–50 cm soil layer at sites representing three land use types in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that the SWHC was higher at the woodland site than the grassland and shrubland, and there was no significant difference between the latter two sites, the trend of SWA was similar to the SWHC. From grassland to woodland, the soil physical properties in the 0–50 cm soil layer partially improved, BD was significantly higher at the grassland site than at the shrubland and woodland sites, the clay and silt contents decreased significantly from grassland to shrubland to woodland and sand content showed the opposite pattern, the soil porosity was higher in the shrubland and woodland than that in the grassland, the soil physical properties across the 0–50 cm soil layer improved. Soil texture, porosity and bulk density were the key factors affecting SWHC and SWA. The results of this study provide insight into the effects of vegetation restoration on local hydrological resources and can inform soil water management and land use planning on the Chinese Loess Plateau.

Feedbacks between vegetation restoration and local precipitation over the Loess Plateau in China

The implementation of large-scale vegetation restoration over the Chinese Loess Plateau has achieved clear improvements in vegetation fraction, as evidenced by large areas of slopes and plains being restored to grassland or forest. However, such large-scale vegetation restoration has altered land-atmosphere exchanges of water and energy, as the land surface characteristics have changed. These variations could affect regional climate, especially local precipitation. Quantitatively evaluating this feedback is an important scientific question in hydrometeorology. This study constructs a coupled land-atmosphere model incorporating vegetation dynamics, and analyzes the spatio-temporal changes of different land use types and land surface parameters over the Loess Plateau. By considering the impacts of vegetation restoration on the water-energy cycle and on land-atmosphere interactions, we quantified the feedback effect of vegetation restoration on local precipitation across the Loess Plateau, and discussed the important underlying processes. To achieve a quantitative evaluation, we designed two simulation experiments, comprising a real scenario with vegetation restoration and a hypothetical scenario without vegetation restoration. These enabled a comparison and analysis of the net impact of vegetation restoration on local precipitation. The results show that vegetation restoration had a positive effect on local precipitation over the Loess Plateau. Observations show that precipitation on the Loess Plateau increased significantly, at a rate of 7.84 mm yr−2, from 2000 to 2015. The simulations show that the contribution of large-scale vegetation restoration to the precipitation increase was about 37.4%, while external atmospheric circulation changes beyond the Loess Plateau contributed the other 62.6%. The average annual precipitation under the vegetation restoration scenario over the Loess Plateau was 12.4% higher than that under the scenario without vegetation restoration. The above research results have important theoretical and practical significance for the ecological protection and optimal development of the Loess Plateau, as well as the sustainable management of vegetation restoration.

Assessment of Land-Use/Cover Changes and Its Ecological Effect in Rapidly Urbanized Areas—Taking Pearl River Delta Urban Agglomeration as a Case

Based on the land-use data of 2000 and 2015, this study makes a quantitative analysis of the ecological environment effect in Pearl River Delta using the ecological environment quality index and the ecological contribution rate of land-use change types. The results showed the following: (1) During 2000–2015, the land-use changes in Pearl River Delta mainly manifested in the reduction of cultivated land, forest land, water area, and unused land, while the area of construction land and grassland showed an increasing trend. The quality of ecological environment in the Pearl River Delta was largely stable but slightly declined overall; (2) Over the past 15 years, the comprehensive ecological environment index of the Pearl River Delta urban agglomeration has decreased by 0.02. With an average annual decrease of 0.11%. The spatial expansion caused by urbanization had the most profound impact on the decline of the ecological environment quality in the Pearl River Delta; (3) The eco-environmental quality indices of various cities in the Pearl River Delta declined to varying degrees. The city with the largest decline was Dongguan, followed by Shenzhen and Zhongshan. The spatial differentiation characteristics of the eco-environmental quality index indicate that the ecological quality preferences of cities distributed around the study area and close to the inland areas, while the ecological quality of the central coastal cities are biased. The quality of the ecological environment is related to the basis of the regional ecological environment. The research results have important practical significance for maintaining regional ecological balance and promoting the sustainable use of land resources, and they provide a reference for the study of the ecological and environmental effects of land-use changes in key cities in economically developed areas.

Response of soil nutrient concentrations and stoichiometry, and greenhouse gas carbon emissions linked to change in land-use of paddy fields in China

The conversion of paddy cropping to vegetable production and other crops is a common agricultural practice, driven by economic benefits. However, soil carbon emissions and nutrient stoichiometric responses to this type of land-use change remain unclear. In this study, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions, Soil Organic Carbon (SOC), total nitrogen (TN), and total phosphorus (TP) concentrations and their stoichiometric relationships were measured over one year, following conversion of paddy fields to vegetable and jasmine crops 10 years ago. Soil CO2 emissions increased by 1.16 and 2.35 times after conversion to vegetable and jasmine production, respectively, and soil CH4 and N2O emissions decreased by 52 and 66%, and 12.3 and 42.5%, respectively. Global warming potential increased by 0.81 and 1.67 times, respectively; the increases in total C emissions were associated with decreases in SOC concentrations. TN decreased by 27% in jasmine soils following conversion from paddy cropping, and TP concentrations increased by 11% in vegetable soils. Carbon soil stocks increased by 19% in vegetable soils and decreased by 11% in jasmine soils, due to changes in SOC concentration and bulk density. Soil CO2 and total C emissions were negatively correlated with soil TN concentration and C:P ratio (p < 0.05), and CH4 emissions were positively correlated with SOC concentrations (p < 0.05) and soil N:P and C:P ratios (p < 0.01). Thus soil elemental stoichiometry was a good indicator of soil nutrient cycling and greenhouse gases emissions. Our findings suggest that the conversion of paddy cropping to vegetable and jasmine production increased C emissions and conversion to jasmine cropping does not lead to retention of soil nutrients, whereas TP concentration and SOC stocks increased following conversion to vegetable cropping. This study highlights that future conversion of paddy soils to vegetable or tree crops will have implications on carbon balances and global warming.

Characteristics of land use change Tupu in Shandong province based on multi-source data

In recent years, with the rapid pace of urbanization in China and people’s increasingly high requirements for living environment, human activities on land demand are increasing. Based on the theory and method of Geo-information Tupu, we synthesize the land use change Tupu of Shandong province during the period 2010-2018 by taking the remote sensing interpretation data as the spatial data source, so as to analyze the spatial and temporal pattern of land use change in Shandong province in recent years. The results show that: (1) the main types of land use change in Shandong province are the mutual transformation of cropland and construction land and the transformation of cropland and construction land to water area. (2) in terms of space, “ construction land→ water area” and“ cropland→ construction land” have the most concentrated distribution. The former is significantly distributed in the coastal areas of Binzhou, Dongying and Weifang. (3) the transfer of cropland into related land use change types, with larger area, smaller spatial separation and more concentrated distribution; The transfer area of woodland is small, and the spatial separation degree is large. (4) in general, the cropland area is decreasing while the construction land area is increasing.

Evaluasi Pemanfaatan Ruang Kabupaten Lampung Selatan Tahun 2012-2017

Land use in South Lampung Regency continues to experience development, which is influenced by rapid population growth within five years after the planning year began in 2010. Various types of land-use changes that have occurred in South Lampung Regency indicate in the spatial changes of South Lampung Regency, which has been planned especially in the Regional Spatial Plan (RTRW) of South Lampung Regency for 2011-2031, one of which is the plantation area (belonging to PTPN VII) to become land for ITERA. There are preventive measures that can be made so that the spatial plan can still be following its development objectives. It is necessary to research by evaluating South Lampung Regency's spatial use based on its spatial plan, especially by RTRW. Based on the analysis, there is a deviation of land use in South Lampung Regency with 48.46%, which is divided into spatial structure plans and spatial pattern plans.

Quantification Prediction Soil Losses in Nakhon Ratchasima, Thailand

Soil loss, accelerated by human activity, has become one of the world's most serious environmental problems because it poses significant threat to natural resources and the environment. This research focuses on soil loss in the future for sustainable land use planning for 9 watersheds over 20 years in Nakhon Ratchasima, Thailand. The integrated CA-Markov with GIS was applied to forecast 9 types of land use changes to analyze for soil conservation factors as of International Land Loss Equation (USLE). The land use change maps in 2019, 2023, 2027, 2031, and 2035 had been projected for land use predictions from 2011 and 2015 databases. The validation for the correctness of the production land use change map has 91.46% accuracy. The soil loss analysis of targeted study targets were divided into soil loss for the 9 watersheds and covers the overall provinces to determine the proportion of sediment generated in each watershed encountered the risk. The simulation results showed that the soil loss for the entire province may reach the highest soil loss at 329,271 T·km-2·y-1 with the mean at 2,929.06 T·km-2·y-1. The amount of soil loss in 2035 will be 551.26 x 106 T·y-1. In terms of soil loss of all 9 water watersheds, LTK was found the highest soil loss with 238,606 T·km-2·y-1. The average soil loss is estimated at 135.33 x 106 T·y-1, accounting for 25% of the total area. In comparison among the watershed areas, the amount of soil loss in LPP with highest soil loss rate per area at 51,100.51 ton per area per year. The future land use maps can be used to assess soil loss and can serve as an early warning system. The determination of policies to prevent future environmental problems is critical to controlling improper changes or adversely affecting the local environment.

The influence of change of land-use type on hydrological cycle

Change of land-use pattern causes the change of underlying surface environment in the basin, thus influencing the source and sink of hydrological cycle in the study area and to greatly affect the groundwater level. In order to study the relationship between underlying surface change and groundwater level, this paper quantitatively analyzed the remote sensing images of the Hailiutu River basin acquired in different periods and collected long-series groundwater monitoring data, and this paper drew a groundwater level change map by calculating the transfer matrix of different land-use types. On this basis, this paper analyzed the groundwater level and influential factors for the transfer amount of different land-use types. Results showed that the change in groundwater level was mainly influenced by the underlying surface change. The land-use types exhibited strong tempo-spatial transformation. Where there was a drastic change of land-use type, there was a sharp change in groundwater level, indicating that the change of land-use type greatly influenced the underlying surface and was positively correlated with the spatial distribution of groundwater level.

Exploring the long-term vegetation dynamics of different ecological zones in the farming-pastoral ecotone in northern China.

The vegetation in the farming-pastoral ecotone in northern China is influenced by both natural and anthropogenic factors and has undergone drastic changes in the past decades. The farming-pastoral ecotone is the transition zone from agriculture to animal husbandry. The ecological environment of this ecotone is complex and fragile. Most researches have primarily focused on the entire farming-pastoral ecotone, seldomly considering the differences between different ecological zones characterized by soil, climate, and biome conditions. Based on the long time series of leaf area index (LAI) data, meteorological data, and land-use dataset, this study analyzed LAI variation trends, the correlations between LAI and climate factors, and the impact of land-use type change on vegetation in the farming-pastoral ecotone in northern China. Moreover, this paper makes a full study of the changes of the whole study area from the perspective of the differences between different ecological zones. The results showed that over 36years, areas with vegetation improvements were considerably larger than those with degradations. However, there were still 49.56% of the total area showing no significant vegetation change. There are differences in vegetation change and response to climate between the forest ecological zones and the grassland ecological zones. The vegetation improvement trends of the forest ecological zones were larger and more sensitive to temperature, while the vegetation improvements of the grassland ecological zones were relatively small, and were more sensitive to precipitation. Human activities promote LAI changes in areas close to the forest ecological zones. The change of land use indicates that the decrease of the overall natural vegetation area has not resulted in decreasing LAI. And there is a growing trend of woodland area in the grassland ecological zones. The study provides a theoretical basis for the management of the environment and vegetation in the farming-pastoral ecotone in northern China.

Natural amenities and low-density residential development: Magnitude and spatial scale of influences

Low-density residential development in rural areas is an important land use trend in many parts of the world, and has disproportionate ecological impacts due to its large footprint relative to population. It is widely suggested that this type of land use change is driven in part by natural amenities, raising the concern that locations of high natural value are most rapid to develop. We examine the contribution of natural amenities to the probability of low-density development controlling for more traditional drivers of land use change. We do so considering the influence of natural amenities at two scales, individual plots, and the larger communities in the immediate vicinity. We use a unique primary dataset based on photo interpretation of high resolution imagery to capture residential development at the scale of a single house between 1990 and 2010. We combine these data with spatially-referenced census and other secondary data to estimate a multilevel regression model of the probability of residential land conversion. Our results demonstrate that communities near National Parks, other public lands and ski resorts experienced significantly higher rates of residential land conversion than those further from these amenities. Within communities, undeveloped plots that were 10 min closer than average to public land had a 67 % higher probability of conversion to residential use holding other characteristics constant, plots that were 75 min closer than average to a large lake had a 139 % higher probability of conversion, and plots with 1 standard deviation more forest/non-forest variation had a 44 % higher probability of conversion. Our findings regarding community and plot level influences of natural amenities on rural development are unique in the land use literature, and are important for identifying which communities and individual parcels have the highest probability of development. This can inform policy makers’ and conservationists’ efforts to protect places facing the highest threats, and help both regional and local land-use planners manage tradeoffs between environmental protection and economic growth.

Application of hydrodynamic models for designing structural measures for river flood mitigation: the case of Kulfo River in southern Ethiopia

Flood is one of life-threatening events in different parts of Ethiopia. The causes of flood might vary from place to place, for instance, rates of deforestation, agricultural expansion, urbanization, wetland drainage, climate change, siltation of river bed, and several other types of land use change might be the cause for flood in different rivers banks. This study aims to assess, investigate, and design suitable river training works on lower Kulfo river reach. The study reach has been seriously affected by extreme floods due to the above reasons. For minimizing the loss due to flood, and to use the advantage of flood for different developmental activities various flood control measures should be adopted. The flood control measures which should more correctly be termed as “flood management” can be planed either through structural engineering measures or non-structural measures. Structural measures comprise retarding structures which store flood water, channel improvements which increase flood-carrying capacity of the river, embankments, and levees which keep the waterway from flood-prone area, detention basin which retards and absorbs most of the floodwater. Within the identified 6 km reach, field investigation including secondary data collection has been done to predict the flood extent using 1D hydrodynamic model, HECRAS and HEC Geo RAS. Estimated flood depth and extent helped us in fixing the dimension of different river training structures selected. The modelling result indicates a maximum channel bed flood depth of 4.3 m and flood plain flood depth 2.3 m obtained using a 100-year return flow. Analysis of soil samples indicates that the lower reach of Kulfo river is gravel and sand dominated meandering river, with estimated scour depth up to 3.41 m along the river course. Levees have been designed in conjunction with Groynes to protect the Upstream farm located at the prison and upper part of the Limat households. Frequent floods happening near both bridges shall be reduced by using Guide banks without influencing the bridges and diversion structures. Consideration is given for the ecosystem to stay in equilibrium, by providing suitable outer slopes so that plantation is possible on the top and side slope of the levees and guide banks.