scholarly journals Influence of stream habitat and land use on benthic macroinvertebrate indicators of stream quality of selected above-tidal streams in the Houston-Galveston Area Council service area, Texas, 1997-98

2001 ◽  
Author(s):  
Nathaniel Narvaez ◽  
John Griffis

The use of macroinvertebrates as indicator organisms is cheap, easy, and a reliable way to determine water quality. To determine the effects on man-made structures on macroinvertebrate communities and stream quality, comparisons were made between macroinvertebrate samples from established open canopy upstream and forested downstream reaches, and adjacent reaches with man-made structures (road bridge and foot bridge). Macroinvertebrates were collected using a D-frame kicknet, following Illinois Riverwatch protocol. There was little difference in Macroinvertebrate Biotic Indices and Shannon Diversity Indices between established and adjacent reaches. However, there were significant differences between EPT/non-EPT and pollution intolerant/tolerant organisms found between all reaches, and between all paired comparisons of the established and adjacent reaches (p< 0.05), except when comparing the forested reach with the road bridge reach (EPT/non-EPT, p=0.583; pollution intolerant/tolerant, p=0.542), the forested reach and the road bridge (EPT/non-EPT, p=0.84), and the forested reach with the adjacent foot bridge reach (EPT/non-EPT, p=0.489). Noticeable differences in taxa distribution occurred between all reaches. Different samples obtained from different reaches indicated varying distribution of taxa, with the forested reach having more high quality EPT taxa and individuals, however all reaches displayed similar water quality of “fair”, with little impact from man-made structures.


Author(s):  
Andreas Christian Braun

Land-use and land-cover analyses based on satellite image classification are used in most, if not all, sub-disciplines of physical geography. Data availability and increasingly simple image classification techniques – nowadays, even implemented in simple geographic information systems – increase the use of such analyses. To assess the quality of such land-use analyses, accuracy metrics are applied. The results are considered to have sufficient quality, exceeding thresholds published in the literature. A typical practice in many studies is to confuse accuracy in remote sensing with quality, as required by physical geography. However, notions such as quality are subject to normative considerations and performative practices, which differ between scientific domains. Recent calls for critical physical geography have stressed that scientific results cannot be understood separately from the values and practices underlying them. This article critically discusses the specific understanding of quality in remote sensing, outlining norms and practices shaping it and their relation to physical geography. It points out that, as a seeming paradox, results considered more accurate in remote sensing terms can be less informative – or meaningful – in geographical terms. Finally, a roadmap of how to apply remote sensing land-use analyses more constructively in physical geography is proposed.


2021 ◽  
Vol 6 (1) ◽  
pp. 82-92
Author(s):  
Tran Tuan Nguyen

Abstract This article describes the relationship between the land use purpose conversion and households’ livelihoods in suburban Vinh City, Nghe An province. In the survey with 170 households losing their land to build the VSIP Nghe An industrial park project, this article shows the double impact of this issue. (1) On the positive side, households’ quality of life in the current period shows a significant improvement. They are living in better conditions with more spacious houses and modern facilities than before. The average income of households increased by 900 USD than before. (2) On the negative side, the unemployment rate increases with women older than 35 years and men older than 40 years. Along with the improper use of compensation received, income sustainability is a doubt for these households’ future.


2020 ◽  
Vol 9 (9) ◽  
pp. 531
Author(s):  
ShuZhu Wang ◽  
Qi Zhou ◽  
YuanJian Tian

OpenStreetMap (OSM) data are considered essential for land-use and land-cover (LULC) mapping despite their lack of quality. Most relevant studies have employed an LULC reference dataset for quality assessment, but such a reference dataset is not freely available for most countries and regions. Thus, this study conducts an intrinsic quality assessment of the OSM-based LULC dataset (i.e., without using a reference LULC dataset) by examining the patterns of both its completeness and diversity. With China chosen as the study area, an OSM-based LULC dataset of the country was first generated and validated by using various accuracy measures. Both its completeness and diversity patterns were then mapped and analyzed in terms of each prefecture-level division of the country. The results showed the following: (1) While the overall accuracy was as high as 82.2%, most complete regions of China were not mapped well owing to a lack of diverse LULC classes. (2) In terms of socioeconomic factors and the number of contributors, higher correlations were noted for diversity patterns than completeness patterns; thus, the diversity pattern is a better reflection of socioeconomic factors and the spatial patterns of contributors. (3) Both the completeness and the diversity patterns can be combined to better understand an OSM-based LULC dataset. These results indicate that it is useful to consider diversity as a supplement for intrinsically assessing the quality of an OSM-based LULC dataset. This analytical method can also be applied to other countries and regions.


2019 ◽  
Vol 15 (1) ◽  
pp. 70 ◽  
Author(s):  
Warsilan Warsilan

As the capital of the province of East Kalimantan, Samarinda City developments has a rapid progress from year to year. Samarinda City Development has a tendency oriented towards infrastructure development without regard to the existence of the quality of the existing environment. Imbalance of development in Samarinda city is to start decreasing the water catchment area, so its make increasing intensity of flood in the Samarinda City. The purpose of this study was to analyze the impact of changes in land use in the Samarinda city on the ability of the water catchment area. This research method using descriptive approach, the data collection system of primary and secondary. Intensity flood in the Samarinda city  is increasing from year to year, this condition happened as a problem that always occurs during the rainy season. Current development trends, always take an area that should be an infiltration  area for Samarinda City. Culture and inadequate infrastructure conditions such as lack of system of drainage and polder, was another factor causing the high intensity of flood  in Samarinda City. Therefore, the relevant regulations development guidelines for Samarinda  City must consider all aspects of planning, in this case especially the important of a balance of cultivated land and protected areas or zones.Keywords: Changes in land use; intensity of puddles; Samarinda


2021 ◽  
Vol 109 ◽  
pp. 105679
Author(s):  
António Carlos Pinheiro Fernandes ◽  
Lisa Maria de Oliveira Martins ◽  
Fernando António Leal Pacheco ◽  
Luís Filipe Sanches Fernandes

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