ArcGIS Model Research Articles

Vertical accuracy assessment for open-source digital elevation models using GPS control points and watershed basins delineation using GIS

Digital elevation models (DEMs) are crucial for numerous assessments of the Earth's surface, so this research aim to evaluate the quality of several open source DEMs like advanced spaceborne thermal emission and reflection radiometer global DEM (ASTER GDEM), shuttle radar topography mission DEM (SRTM DEM), SENTINEL-1, and TerraSAR-X for digital elevation measurement (TanDEM-X). TanDEM-X is one of the newest DEM models; however, ASTER and SRTM are still the most used. To evaluate the qualities of these DEMs, the vertical accuracies of ASTER, STRM (all 30 m), SRTM, TanDEM-X (90 m), and SENTINEL 1 (range from 5 to 12.5 m) were tested using GPS reference points and The RMSE gave the values of ± 3.56 m ± 57.68 m, ±5.89 m, ±10.21 m and ± 20.25 mfor used SRTM1, SENTINEL-1, SRTM3, TanDEM-X, and ASTER DEMs respectively. As is well known, obtaining a high-quality DEM is exceedingly challenging since it is time-consuming, expensive, and often constrained, therefore this study examined how to enhance SRTM1 as it gave the best result and assessed the effects of increasing the number of points on digital elevation model accuracy by using raster calculator and merge model in ArcGIS. The results showed that the merge model method gave the best result and, by increasing the number of reference points, the accuracy increased. The DEM produced by the enhanced SRTM (iSRTM) demonstrated noticeably better outcomes than the baseline SRTM DEM, with around 3.56 m RMSE.In this research, STRM-1 DEM is used to determine watershed basin delineation. The topographic map showed significant variations in the level of the Earth's surface, as the heights of the area ranged between 20 m and 120 m. The number of watersheds extracted in the Benban is 132 with different areas, the large area is about 72.14 km2, while the small area is about 1.13 km2, and between those areas, there are various areas. The largest recorded watershed circumference reached 48.94 km in area (72.14 km2), while the lowest recorded perimeter is 5.40 km for the area (1.13 km2).

Effect of the Proposed Outlets on the Hydrodynamic Behavior and Water Quality of the South-West Part of the Al Hammar Marsh

The current study aims to find a new plan to manage the water quality of the western part of the Hammar Marsh to reduce the salts that cause problems for the marshes and preserve their environmental life by isolating the southwestern part of the Hammar Marsh by closing the outlet under the railway embankment. The outlet is discharging saline water to the east-western part of Al Hammar Marsh. After isolating the southwestern part of the marsh, a new outlet is proposed. The impact of the flow hydrodynamics on improving the water quality was simulated using the SMS model. The hydrodynamics and water quality simulation models for the marsh are : a hydrodynamic model and average depth (SMS RMA2) and a two-dimensional water quality model (SMS RM4). The Civil3D was used to determine the area elevation curve for the marsh, while the shape file for the study area was prepared using the Arc-GIS model. The first model is used to simulate the flow conditions in the marsh (water depth and velocity vectors), while the second model is used to simulate the salinity of the water (Total Dissolved Solids (TDS)). For calibration and verification the models, water samples were taken from ten selected locations within the marsh. The measurements were conducted on 1st January and on 2nd February 2022. The simulation results were validated with the field measurement, and the discrepancy between the simulated and measured water depth was found to be 11%. Many scenarios are based on the proposed recommended outlet that considerably reduces TDS concentration in the Al Hammar marsh. Three scenarios were run on the proposed outlet to maintain a submerged area of 88 km2, and to compare the three scenarios, ten points were selected in different locations, where the average TDS ratio for the first scenario was 7528 mg/l, the second scenario was 6982 mg/l and for the third scenario was 8069 mg/l. Results showed that the proposed outlet would improve the hydrodynamics of the flow and reduce the TDS concentration by 10% in addition to controlling the contamination of east western part of the marsh

Based on multiple environmental factors to explore the habitat distribution of licorice (Glycyrrhiza uralensis) in different time and space

As a traditional medicinal plant, licorice (Glycyrrhiza uralensis) with high medicinal and economic value and its demand is increasing around the world. In recent decades, the endless human excavation and climate change have reduced the natural habitat of licorice. Identifying the suitable habitat of licorice and climatic factors is crucial to formulating effective protection and management strategies. This study simulated the suitability geographic distribution of licorice in the current period by combining climate and topographic variables and predicted the possible changes in suitable habitats for licorice under different climate warming scenarios (RCP8.5, 6.0, 4.5, 2.6) in the future (2041–2080) based on Maxent and ArcGIS models. The study results showed that annual average temperature, temperature seasonality, annual precipitation and elevation were the primary eco-factors influencing the spatial distribution of licorice. Currently, the high, medium and low suitable areas of licorice are 108.87 × 104 km2, 70.29 × 104 km2 and 122.80 × 104 km2, respectively. These habitat regions were mainly distributed in the northwest, northeast and north of China. The research found that the habitat suitability and habitat range of licorice will increase in the future, while the potentially highly suitable habitat will decrease and the habitat fragmentation will increase with the intensification of global warming. The analysis results can provide a theoretical reference for the formulation of protection strategies and the selection of suitable planting areas for licorice.

DEVELOPING WATERSHED ANALYSIS TOOL IN GIS ENVIRNOMENT

The process of deriving the hydrological parameters in the GIS environment requires semi-automated procedures that depend on the user’s experience with the tools designed within the system, and this in turn may cause technical errors as a result of implementing the sequential steps that address an issue, so there was a need to develop tools that depend on the total automated derivation reduce the number of steps while reducing the time required for implementation. As a result, in the presented work, a hydrological toll was created as an automated workflow using Python and ArcGIS Model Builder, which will be explained. The workflow for this tool was developed in Python and applied to Iraq's northeast region. Through the statistical comparison of all derived stream configuration results using DEM, an ideal threshold value was found to maximize drainage configuration. The code was successful in automatically estimating the right ranking of specified stream orders without any further manual processes. Therefore, the developed tool saves effort and time, making it an extremely valuable function for large catchment basins.

Suitability of Green City Criteria (LEED) According to the Egyptian Special Environmental Characteristics

The research aims to suit the criteria for classifying green cities according to the characteristics of the Egyptian environmental zones to select the most relevant zone for sustainable green cities. The Egyptian cities consume large quantities of materials, energy, and water causing different problems facing cities and their population. The criteria of sustainable green cities should be done according to the various characteristics of environmental zones in Egypt. The leadership in energy and environmental design (LEED) criteria for the Egyptian cities and communities’ system is selected according to the characteristics of environmental zones in Egypt, aiming to select the most relevant zones to construct sustainable green cities. According to the ecological, geographical, economic, political, social, historical, urban, and cultural characteristics of environmental zones that are different from one zone to another in Egypt, the influencing factors in the classification criteria are introduced to show the incentives, capabilities, and challenges facing cities in making green and sustainable transformation by using weighited overlay model in Arc GIS. By using the suitability scoring system, the most suitable environmental zone, namely the dry coastal zone, has the motivation and ability to transform the city into a green and sustainable city according to its particular environmental characteristics.

Assessment of Land Use Pattern and Landscape Ecological Risk in the Chengdu-Chongqing Economic Circle, Southwestern China

The Chengdu-Chongqing Economic Circle (CCEC) is becoming the fourth growth pole in China after the Yangtze River Delta Economic Circle (YRDEC); Guangdong, Hong Kong, and Macao Economic Circle (GBAEC); Beijing, Tianjin, and Hebei Economic Circle (BTHEC). The land use and landscape ecological management of the CCEC is critical to its social and economic development. Using ArcGIS modeling and Fragstats processing methods, we divided the CCEC into 5 km × 5 km ecological risk areas and constructed a landscape ecological risk index evaluation model to calculate the spatial and temporal dynamic changes in the urban expansion and landscape ecological risk over the last 20 years. The results show that the land use was mainly cultivated land, which exhibited a decreasing trend and was mainly converted to construction land and forest land. The change in the construction land exhibited a continuous expansion trend with the dual core in Chengdu-Chongqing. The average risk of 10,155 risk communities was about 0.16. The expansion of human activities increased the landscape ecological risk of the construction land, and the risk of the edge of the cultivated land was higher than the internal risk value. The ecological risk index values of 16 cities in the study area ranged from 0.02 to 0.28. The resistance of the landscape pattern to external disturbance was stronger than that in other regions of China. The landscape ecological risk is controllable overall. However, the higher level of economic development in Chengdu, Chongqing, and other mature cities poses a greater landscape ecological risk. The results of this research provide an important reference for promoting the optimization and construction of the land space in the CCEC, building ecological shelters, and preventing ecological risk in the upper reaches of the Yangtze River.

Insights for booster chlorination strategy based on DBPs control in a large-scale water supply system

Based on a one-year field investigation of disinfection by-products (DBPs) in large scale water distribution system (LSWDS), the various characteristics of DBPs together with their correlation with booster chlorination were elaborated through ArcGIS model. Furthermore, the effects of booster chlorination on DBP formation were investigated through simulated experiments. Residual chlorine showed a strong relationship with occurrence of different DBPs in LSWDS, and the yield of DBPs increased significantly after booster chlorination. The simulated chlorination experiments showed that diminution of the ratio of primary to secondary (booster) chlorination dosage, and delaying the secondary chlorine addition reduced the generation of DBPs during water conveyance. The yield concentrations of THMs and HAAs obviously increased after booster chlorination. The correlation between HAAs and chlorine dosage is weaker in the field research than in the simulation experiment while THMs had a positive correlation with the chlorine addition in both field research and simulation experiment.

A Performance Comparison between GIS-based and Neuron Network Methods for Flood Susceptibility Assessment in Ayutthaya Province

Flooding has been a long withstanding issue in Thailand. Due to its geographical setup, mitigation and management of floods are challenging and hard to execute. One of the tools used in managing the events is “flood susceptibility mapping,” in which an incident probability as well as a rescue path is estimated and planned. To create one, the traditional GIS method called FRAM (flood risk assessment model), combined with AHP (analytical hierarchy process), is used and implemented on ArcGIS software. In this method, we first created a comparison table to compute weights for each of the selected factors. Then the computed weights were used in the FRAM model in ArcGIS to create a flood susceptibility map for each region. Each region was then classified as very high, high, medium, low, and very low risk. On the other hand, in computer science, machine learning and AI are prevalent and being adopted to various domains, promising the effectiveness of the method, potentially beat the forementioned traditional method. Therefore, ANN (artificial neural network) is adopted in this work to create the flood susceptibility map. The ANN technique is developed by using causal factors. The ANN classifies areas as either flood areas or flood-free areas. The 2 methods from different disciplines (GIS and Computer Science) are applied and described in this paper with the intention to prove whether the machine learning is really efficient and can outperform the traditional GIS approach. Data on Thailand’s Ayutthaya Province is used in this work as a case study - in order to assess flood prone areas and compared for performance evaluation. Both of which use the 6 selected factors according to the literature: (i) flow accumulation, (ii) elevation, (iii) land use, (iv) rainfall intensity, (v) slope and (vi) soil types. The results from the 2 methods were verified with historical flood data and compared. The results showed that ANN (obtained via sensitivity analysis) outperformed the FRAM with precision of 79.90 %, recall of 79.04 %, F1-score of 79.08 % and accuracy of 79.31 %. In addition, we found that (according to our ANN experiments) the main causal factors related to flood susceptibility map only included 3 factors: flow accumulation, elevation, and soil types. Therefore, the proposed methodology for assessment of flood susceptibility areas using these 3 factors could be considered sufficient and applied to other regions in related applications, when needed.

Landslide Hazard Zonation along the MH SH-73 at Kelghar Ghat, Satara, Maharashtra

Road transportation is the most common victim of landslide in the world. The present study investigates the landslide hazard zonation along the MH SH-73 at Kelghar ghat between Medha and Mahabaleshwar hill station of Maharashtra. Remote Sensing and GIS were used for the landslide hazard zonation of this section. The ghat section was buffered 100 m on both side to define the extent of study area based on the field investigation. The study incorporated predefined important landslide causative factors, viz. slope, rainfall, relief, lithology, soil depth, soil erosion, soil texture, land use / land cover, drainage distance, drainage density, lineament distance, lineament density, aspect, temperature, landslide inventory and in this approach fifteen thematic layers were prepared in GIS platform. The weight and score were assigned to each thematic layer based on heuristic approach on their relative importance in causing landslide. Multi-criteria model in ArcGIS 10.5 software were used for the mapping landslide hazard zones and it were classified into six zones: very high (1.3 %), high (1.7 %), moderate (3.4 %), low (7.6 %) very low (8.4 %) and no risk zone (77.7 %). The final result of this research can help for proper mitigation and adaptation measures for engineers, planners and administrators for this ghat section. Keywords: GIS, Landslide Hazard Zonation, Remote Sensing, Susceptibility, Sahyadri, Kelghar.

Species diversity and spatial distribution of CL/VL vectors: assessing bioclimatic effect on expression plasticity of genes possessing vaccine properties isolated from wild-collected sand flies in endemic areas of Iran

BackgroundLeishmaniasis is one of the ten most important neglected tropical diseases worldwide. Understanding the distribution of vectors of visceral and cutaneous leishmaniasis (VL/CL) is one of the significant strategic frameworks to control leishmaniasis. In this study, the extent of the bioclimatic variability was investigated to recognize a rigorous cartographic of the spatial distribution of VL/CL vectors as risk-maps using ArcGIS modeling system. Moreover, the effect of bioclimatic diversity on the fold change expression of genes possessing vaccine traits (SP15 and LeIF) was evaluated in each bioclimatic region using real-time PCR analysis.MethodsThe Inverse Distance Weighting interpolation method was used to obtain accurate geography map in closely-related distances. Bioclimatic indices were computed and vectors spatial distribution was analyzed in ArcGIS10.3.1 system. Species biodiversity was calculated based on Shannon diversity index using Rv.3.5.3. Expression fold change of SP15 and LeIF genes was evaluated using cDNA synthesis and RT-qPCR analysis.ResultsFrequency of Phlebotomus papatasi was predominant in plains areas of Mountainous bioclimate covering the CL hot spots. Mediterranean region was recognized as an important bioclimate harboring prevalent patterns of VL vectors. Semi-arid bioclimate was identified as a major contributing factor to up-regulate salivary-SP15 gene expression (P = 0.0050, P < 0.05). Also, Mediterranean bioclimate had considerable effect on up-regulation of Leishmania-LeIF gene in gravid and semi-gravid P. papatasi population (P = 0.0109, P < 0.05).ConclusionsThe diversity and spatial distribution of CL/VL vectors associated with bioclimatic regionalization obtained in our research provide epidemiological risk maps and establish more effectively control measures against leishmaniasis. Oscillations in gene expression indicate that each gene has its own features, which are profoundly affected by bioclimatic characteristics and physiological status of sand flies. Given the efficacy of species-specific antigens for vaccine production, it is essential to consider bioclimatic factors that have a fundamental role in affecting the regulatory regions of environmentally responsive loci for genes used in vaccine design.

Ecological assessment of current and future Pogostemon cablin Benth. potential planting regions in China based on MaxEnt and ArcGIS models

Pogostemon cablin Benth. is a medicinal herb and member of the Lamiaceae family. P. cablin incense serves as an important raw material for the production of specific chemicals and pharmaceutical compounds, and as such, the demand for such incense has been rising annually. It is therefore critical that researchers establish the environmental factors that influence optimal P. cablin growth and development. Herein, we have sought to predict potential regions for future cultivation of this medicinal herb and have developed a theoretical framework for such cultivation. For this analysis, we utilized geographic records pertaining to the planting of P. cablin collected in recent years via field visits. These records, together with 19 environmental variables, we utilized for maximum entropy algorithm (MaxEnt) modeling and an ArcGIS 10.2 software analysis in an effort to identify the key environmental parameters associated with P. cablin cultivation. The primary factors associated with P. cablin cultivation outcomes were ultimately found to be mean annual temperature, mean temperature of the warmest quarter, max temperature of the coldest month, and mean temperature of driest quarter. These results suggested that southwestern Guangdong, a small portion of central Guangdong, and southern Hainan are all highly suited to P. cablin cultivation, while southeastern Guangxi and the majority of the area outside of central Guangdong are moderately well suited to such cultivation, and the more suitable regions for artificial P. cablin cultivation will be accessible in the future. Together, our data provide a theoretical framework for the optimal planting and growth of this important medicinal herb, thereby reducing the manpower and material resources associated with its cultivation.

Projecting Land use change with neural network and GIS in northern Melbourne for 2014–2050

ABSTRACT Melbourne is one of the most livable cities in the world and it is expected to become a global city of opportunities by 2050. These features along with some of the challenges Melbourne will face with in the future, necessitate land use change simulations. Therefore, land use changes in north Melbourne with an area of 2,425.42 km2 during 2014–2019 and its future changes until 2030 and 2050 have been simulated. Landsat 8 Operational Land Imager (OLI) and Multilayer Perceptron (MLP) neural networks were used along with Markov chain model in ArcGIS and TerrSet software. Results showed that while proportions of residential and industrial–commercial land uses increased from 35.90% (870.70 km2) in 2014 to 38.53% (934.50 km2) in 2019, that of forest and agricultural-grassland decreased from 62.86% (1,524.01 km2) in 2014 to 57.76% (1,400.99 km2) in 2019. Similarly, the simulation results show that residential and industrial–commercial land use will increase to 42.86% (1,037.139 km2) and 44.53% (1,079.99 km2) by 2030 and 2050, respectively. In the same period, forest and grassland-agricultural land uses are respectively expected to decline from 53.53% (1298.53 km2) to 51.76% (1255.49 km2). Spatial changes will occur mostly in the north and northwest of the Melbourne.

Raw material exploitation at the Middle Paleolithic site of Nesher Ramla, Israel

The affordance of raw materials around prehistoric sites can affect knappers’ decision-making process regarding raw material procurement. The Levant presents a rich flint affordance area in which a case study on the organizational decisions of hunter-gatherers regarding raw materials can be tested. Here we examine Unit IIb from the Nesher Ramla site (MIS 5), located in central Israel, in an area rich in potential flint sources. An ArcGIS model was used to create a predictive model for daily exploitation territories (DETs) around the site. We present a three-stage study: (a) a pedestrian survey to locate flint sources; (b) establishment of visual similarities between flint artifacts and potential sources; and (c) a geochemical analysis (obtained through inductively coupled plasma (ICP) mass spectrometry and ICP atomic emission spectrometry); of both geological and archaeological flint that confirms the visual analysis.The results show a uniform pattern of using mainly local flint material from abundant and rich Senonian outcrops that was brought and knapped on site. In addition, the use of less available Eocene material was found, mainly in tools and debitage, suggesting that this type was used as personal gear. We suggest that the unique uniform pattern of the raw material procurement strategy at the site is related to the site's function as a series of short-term camps, task-oriented towards hunting activities and animal consumption and processing.

ArcGIS-mapping to sustainable wastewater management in Greece: siting artificial wetlands systems in a biosystem

&lt;p&gt;In this work, the ArcGIS technology combines analogue and digital geospatial data to derive multiple resolution meshes with a triangulated irregular networks (TINs) approach that serves to integrate the geospatial data such as surface topography, hydro graphic features and land surface characteristics into an adaptive representation of a basin biosystem. The ArcGIS model that has been developed is applied at the municipal level to a small remote settlement with less than 2000 people in Northern Greece. The aim was a site assessment for constructing an artificial wetland (ATW) system as a viable solution to the wastewater management problem and protection of biosystems. This study demonstrates that there are discrepancies in Greece between the existing open geospatial data and on the basis of the results from our study we can conclude that this combination of local maps and geographic information in ArcGIS with a TIN approach increases our knowledge of the physical terrain. It accordingly facilitates the analysis and implementation of action plans by selecting suitable sites for construction of ATW systems in small remote settlements. We moreover discuss problems regarding spatial data quality and scale and provide suggestions for improvement while the desktop classification steps can be easily reproduced for other data-similar countries.&lt;/p&gt;&#x0D;

Hydrological Response of Land Use Land Cover Change on Stream Flow of Anger Watershed, Blue Nile Basin, Ethiopia

Stream flow of Anger watershed (7,982 km2), located in Western Oromia Regional State, Ethiopia was simulated by using soil and water assessment tool (SWAT) model. Assessment of layer staking, mosaicking, image classification and accuracy was carried by ArcGIS. The main target of this study was to determine the SWAT Model applicability and impact of past land-use land-cover change on stream flow of the Anger watershed. The time series data from 1990 to 1999 was used for model parameter calibration, and data from 2000 to 2004 were used to validate the model using the input parameter set. The performance of the SWAT model was evaluated by both R2 time series plots and ENS the statistical measures. The results of the model during calibration for monthly stream flow was R2= 0.90, ENS= 0.76 and during validation R2= 0.84, ENS= 0.63 respectively. Validation of image classification is achieved through Mosaicking image and Google Earth image. The performance of the Arc GIS model was evaluated by using the overall accuracy and kapa coefficient. The agreement between classified land use image and ground truth of the year 1986, 2000 and 2010 were showed a good agreement with result of overall accuracy=88%, 85% and 87% and kapa coefficient=81%, 79% and 82% respectively. Simulation of steam flow of the watershed under the impacts of past land-use land-cover changes can be determined by using SWAT model as a tool for water resources planning and management in this watershed.

Investigating and analyzing women’s sociocultural barriers in using the public transport system in Ahvaz metropolis

The present study aimed to investigate and analyze women’s sociocultural barriers in using public transport of Ahvaz Metropolis. This research is applied-theoretical in terms of purpose and descriptive-analytical in terms of method. The data were collected through library studies, surveys, and interviews with citizens and experts of public transport. The ARAS decision-making method was used to rank the barriers. For zoning the barriers in Ahvaz, the interpolation kriging model in ARCGIS 10.3 software was employed. The results show that the sociocultural barriers of each age group of women are different in each public transport mode. Ranking these barriers shows that sexism looks, men's sexual looks, relatives, families, disapproval, and the drivers’ nonsense talk, respectively, are the major barriers to bus and taxi use, walking, and cycling. In addition, zoning the barriers indicated that the further one moves from north to south of the city, the greater the barriers are. A regional view of this zoning confirms that about 90% of the area of districts 4 and 8 are in the high and very high range, and 30% of district 3 is in the high range. These districts are less favourable than other districts of Ahvaz, but zone 2 is the most favourable one, as it is entirely in low and very low ranges.

Integrated Multi-criteria Land Suitability Evaluation and Mapping for Scaling Malt Barley Varieties in Rain-Fed Production Areas of Ethiopia

Information on variety specific land suitability analysis was not available in Ethiopia. Therefore, integrated multi-criteria land suitability analysis and mapping for contrasting malt barley varieties was carried out to identify where and how much potentially suitable land exists in the country. The main factors considered for analysis include rainfall and temperature during the growing period, length of growing period, digital elevation models, (altitude and slope data) and soil characteristics (types, pH, depth, texture and drainage). The malt barley varieties included are late maturing Bekoji-1, EH1847 and Holker; and early maturing Grace, IBON 174/03 and Sabini. For classification of the data layers according to the degree of suitability for each variety, various reports and other relevant information were reviewed and used in defining the limits of the suitability ranges of malt barley varieties. The overall suitability was computed by multiplying the selected criteria weight by the assigned sub-criteria score and summing these values in the ArcGIS Model Builder. The analysis showing the extent and patterns of suitable land area available for the selected malt barley varieties are presented in the form of tabular data and maps. Highly suitable areas for these varieties include: 125,332 ha for Bekoji-1; 124,004 ha for EH1847; 775,312 ha for Grace; 125,356 ha for Holker; 1,677,388 ha for IBON 174/03; and 307,952 ha for Sabini. The results suggest that current improved malt barley varieties can be targeted for scaling out in the identified land suitability classes in the highlands of Ethiopia. Results also suggest that future research and development works should give priority for developing early maturing, acidic and waterlogging soil tolerant malt barley varieties. The results can be useful for policy and decision making to ensure land resources are used in the most productive and sustainable ways and solve the mismatches between current land use and land suitability for malt barley varieties in the country.

Pollution Load Capacity Analysis of BOD, COD, and TSS in Karang Mumus River, Samarinda

The Rivers in Indonesia often accommodate pollution from all community activities. This happened due to a large number of people who use watersheds for living. One of those rivers is the Karang Mumus River in Samarinda City, East Kalimantan. This study aims to analyze the capacity of the Karang Mumus River pollution load in segments 2, 3 and 4. The analysis model used in this study was the QUAL2Kw and ArcGIS models. The former used to calculate the capacity of river pollution and the latter used to determine land use. The results of the QUAL2Kw Model analysis shown that the capacity of the BOD was exceeded in all segments, COD was exceeded in all segments except segment 3. The entire segment had an allocation of sectoral pollution load originated from domestic activities. This study concluded that the dominant land use of settlements was one of the main causes of this problem.

An Assessment of Urban Park Access Using House-Level Data in Urban China: Through the Lens of Social Equity.

The various benefits of urban green space are gaining increasing attention nowadays. Hence, the distribution of green space has become a scrutinized concern for spatial equity among local governments and the planning scholars. This study is the first quantitative evaluation of urban park accessibility using house-level data in urban China, from the perspective of social equity. We chose Nanjing as the empirical case and examined 2709 real estate units and 79 parks within the city. Accessibility is measured by the 10-min walking distance from homes to the adjacent urban parks. Using the Street Network Analysis model in ArcGIS and the statistical methods in SPSS, the result shows that 60.5% of the real estates in Nanjing are located within a 10-min walk to access urban parks. However, this accessibility is positively correlated with housing prices, and negatively correlated with the age of the buildings, holding all other factors constant. While affluent homeowners capture a high-quality green amenity, newly-built low-income communities, where most residents are classified as a vulnerable population, have the lowest percentage of accessible green space. This study reveals the existing spatial disparities of urban park accessibility among different socio-economic groups in Nanjing, China. Additionally, we found that urban redevelopment projects with greening and the large-scale affordable housing construction are pricing out the urban poor and rural immigrants from the inner city to the urban peripheral areas. This will reduce the accessibility to urban parks and other public service facilities among the lower income families, and exacerbate the inequality among the rich and the poor in terms of their quality of life. Main findings of this study can inform policy decisions regarding equitable park provision in the construction of the green city and the sustainable development in urban China and other developing countries.

Temporal and spatial dynamics of surface run‐off from Lake Basaka catchment (Ethiopia) using SCS‐CN model coupled with remote sensing and GIS

AbstractThe Lake Basaka catchment (Ethiopia) has undergone a significant land use–land cover (LULC) change and lake level rise over the past five decades. Significant quantities of water and sediment flow annually into the lake through erosion processes. An appropriate method of estimating the surface run‐off from such ungauged and dynamic catchment is extremely important for delineating sensitive areas (based on run‐off responses) to be protected and for development of suitable measures to reduce run‐off and associated soil loss. Reliable prediction of run‐off, however, is very difficult and time‐consuming for catchments such as that of Lake Basaka. The present study estimated the dynamics of surface (direct) run‐off using the NRCS‐CN model in ArcGIS, assisted by remote sensing and ancillary data. The results indicated the Lake Basaka catchment experienced significant temporal and spatial variability in its run‐off responses, depending on the rainfall (amount and distribution) pattern and LULC changes. A significant run‐off increase occurred after 1973, consistent with significant LULC changes and lake level increments occurring after that period. A reduced vegetation cover also resulted in increased run‐off coefficient of the lake catchment from 0.11 in the 1970s to 0.23 in the 2000s, indicating the important need to consider possible future LULC evolution when forecasting the lake catchment run‐off behaviour.