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Spatial-temporal heterogeneity and driving factors of water yield services in Citarum river basin unit, West Java, Indonesia

Nahib Irmadi, Ambarwulan Wiwin, Sutrisno Dewayany, Darmawan Mulyanto, Suwarno Yatin, Rahadiati Ati, Suryanta Jaka, Prihanto Yosef, Radiastuti Aninda W., Lumban-Gaol Yustisi

Archives of Environmental Protection

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2023

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Vol. 49, no 1

3--24

EN

Many countries, including Indonesia, face severe water scarcity and groundwater depletion. Monitoring and evaluation of water resources need to be done. In addition, it is also necessary to improve the method of calculating water, which was initially based on a biophysical approach, replaced by a socio-ecological approach. Water yields were estimated using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. The Ordinary Least Square (OLS) and geographic weighted regression (GWR) methods were used to identify and analyze socio-ecological variables for changes in water yields. The purpose of this study was: (1) to analyze the spatial and temporal changes in water yield from 2000 to 2018 in the Citarum River Basin Unit (Citarum RBU) using the InVEST model, and (2) to identify socio-ecological variables as driving factors for changes in water yields using the OLS and GWR methods. The findings revealed the overall annual water yield decreased from 16.64 billion m3 year-1 in the year 2000 to 12.16 billion m3 year-1 in 2018; it was about 4.48 billion m3 (26.91%). The socio-ecological variables in water yields in the Citarum RBU show that climate and socio-economic characteristics contributed 6% and 44%, respectively. Land use/Land cover (LU/LC) and land configuration contribution fell by 20% and 40%, respectively.The main factors underlying the recent changes in water yields include average rainfall, pure dry agriculture, and bare land at 28.53%, 27.73%, and 15.08% for the biophysical model, while 30.28%, 23.77%, and 10.24% for the socio-ecological model, respectively. However, the social-ecological model demonstrated an increase in the contribution rate of climate and socio-economic factors and vice versa for the land use and landscape contribution rate. This circumstance demonstrates that the socio-ecological model is more comprehensive than the biophysical one for evaluating water scarcity.

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Mapping of impervious surfaces with the use of remote sensing imagery: Support Vector Machines classification and GIS-based approach

Sobieraj Janusz, Marín Marcos Fernández, Metelski Dominik

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

129--146

EN

This study focuses on the problem of mapping impervious surfaces in urban areas and aims to use remote sensing data and orthophotos to accurately classify and map these surfaces. Impervious surface indices and green space assessments are widely used in land use and urban planning to evaluate the urban environment. Local governments also rely on impervious surface mapping to calculate stormwater fees and effectively manage stormwater runoff. However, accurately determining the size of impervious surfaces is a significant challenge. This study proposes the use of the Support Vector Machines (SVM) method, a pattern recognition approach that is increasingly used in solving engineering problems, to classify impervious surfaces. The research results demonstrate the effectiveness of the SVM method in accurately estimating impervious surfaces, as evidenced by a high overall accuracy of over 90% (indicated by the Cohen’s Kappa coefficient). A case study of the “Parkowo-Leśne” housing estate in Warsaw, which covers an area of 200,000 m², shows the successful application of the method. In practice, the remote sensing imagery and SVM method allowed accurate calculation of the area of the surface classes studied. The permeable surface represented about 67.4% of the total complex and the impervious surface corresponded to the remaining 32.6%. These results have implications for stormwater management, pollutant control, flood control, emergency management, and the establishment of stormwater fees for individual properties. The use of remote sensing data and the SVM method provides a valuable approach for mapping impervious surfaces and improving urban land use management.

PL

Niniejsze badanie koncentruje się na problemie wyznaczania powierzchni nieprzepuszczalnych na obszarach miejskich i ma na celu wykorzystanie danych teledetekcyjnych i ortofotomap do dokładnej klasyfikacji i wizualizacji tych powierzchni. Wskaźniki powierzchni nieprzepuszczalnych i oceny terenów zielonych są szeroko stosowane w planowaniu przestrzennym i urbanistycznym do oceny środowiska miejskiego. Władze lokalne polegają również na oszacowaniu wielkości powierzchni nieprzepuszczalnych w celu obliczania opłat za wodę deszczową i skutecznego zarządzania odpływem wody deszczowej. Jednak dokładne określenie wielkości nieprzepuszczalnych powierzchni jest poważnym wyzwaniem. W niniejszym badaniu zaproponowano wykorzystanie metody Support Vector Machines (SVM), podejścia opartego na rozpoznawaniu wzorców, które jest coraz częściej stosowane w rozwiązywaniu problemów inżynieryjnych, do klasyfikacji powierzchni nieprzepuszczalnych. Wyniki badań pokazują skuteczność metody SVM w dokładnym szacowaniu powierzchni nieprzepuszczalnych, o czym świadczy wysoka ogólna precyzja wynosząca ponad 90% (na co wskazuje współczynnik Kappa Cohena). Studium przypadku osiedla „Parkowo-Leśne” w Warszawie o powierzchni 200 000 m² pokazuje skuteczne zastosowanie metody. Wyniki wskazują, że powierzchnie przepuszczalne stanowiły około 67,4% całego kompleksu, podczas gdy powierzchnie nieprzepuszczalne stanowiły pozostałe 32,6%. Wyniki te mogą mieć wpływ na zarządzanie wodami opadowymi, kontrolę zanieczyszczeń, zapobieganie powodziom, zarządzanie kryzysowe i ustalanie opłat za wodę opadową dla poszczególnych nieruchomości. Wykorzystanie danych teledetekcyjnych i metody SVM zapewnia cenne podejście do wizualizacji powierzchni nieprzepuszczalnych i poprawy zarządzania użytkowaniem gruntów miejskich.

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Assessment of urbanization impact on urban heat island effect and rainfall for the Surat city

Sharma Arpit, Kale Ganesh D.

Acta Geophysica

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2022

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Vol. 70, no 1

243--264

EN

Population growth and urbanization lead to urban heat island (UHI) phenomenon. Urbanization is occurring at a very high rate in the Surat city. Thus, the study of the urbanization impact on the UHI effect for the Surat city is performed in the present study through studying the impact of land use land cover on the land surface temperature of urban and sub-urban areas of the Surat city over the period May 1998 to May 2018. Also, these effects are compared with that of a nearby sub urban taluka Kamrej, which showed that temperature in urban areas is more than that of the sub-urban areas. Aforesaid facts clearly showing the existence of the UHI effect in the Surat city. As urbanization contributes to climate change, its effects on rainfall are studied by comparing rainfall trends of urban and sub-urban areas of the Surat city and nearby sub-urban area Kamrej. Trend analysis showed that trend magnitude values are higher for the urban areas than sub-urban areas, indicating that UHI effect increases rainfall in urban areas. Hotspot analysis is also performed for the Surat city corresponding to May 2018 to recognize hot spots and cold spots. As the Surat city is highly urbanized, thus, hotspots are more than cold spots.

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Green Space Assessment and Management in Biscay Province, Spain using Remote Sensing Technology

Makinde Esther O., Andonegui Cristina M., Vicario Ainhoa A.

Geomatics and Environmental Engineering

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2021

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Vol. 15, no. 4

21--43

EN

Our ecosystem, particularly forest lands, contains huge amounts of carbon storage in the world today. This study estimated the above ground biomass and carbon stock in the green space of Bilbao Spain using remote sensing technology. Landsat ETM+ and OLI satellite images for year 1999, 2009 and 2019 were used to assess its land use land cover (LULC), change detection, spectral indices and model biomass based on linear regression. The result of the LULC showed that there was an increase in forest vegetation by 12.5% from 1999 to 2009 and a further increase by 2.3% in 2019. However, plantation cover had decreased by 3.5% from 1999–2009; while wetlands had also decreased by 9% within the same period. There was, however, an increase in plantation cover from 2009 to 2019 by 2.1% but a further decrease in wetlands of 4.3%. Further results revealed a positive correlation across the three decades between the widely used Normalized Differential Vegetation Index (NDVI) with other spectral indices such as Enhance Vegetation Index (EVI) and Normalized Differential Moisture Index (NDMI) for biomass were: for 1999 EVI (R2 = 0.1826), NDMI (R2 = 0.0117), for 2009 EVI (R2 = 0.2192), NDMI (R2 = 0.3322), for 2019 EVI (R2 = 0.1258), NDMI (R2 = 0.8148). A reduction in the total carbon stock from 14,221.94 megatons in 1999 to 10,342.44 megatons 2019 was observed. This study concluded that there has been a reduction in the amount of carbon which the Biscay Forest can sequester.