Spatial Analysis of Mangrove Distribution Using Landsat 8 Oli in Badung Regency and Denpasar City, Bali Province, Indonesia

Bali is an island situated among the Indonesian archipelago with huge potential to host mangrove forests. Using remote sensing technology advances, satellite images, such as Landsat images, might be employed to analyse mangrove forest distribution and density. This paper presents an analysis of mangrove distribution in Badung Regency and Denpasar City, Bali, as a basis for the management and conservation of mangrove ecosystems. This study used Landsat 8 OLI images and a vegetation index to analyse the mangrove forest distribution and density in this area. It started by identifying mangrove forests using the RGB 564 band and continued to distinguish between mangrove and non-mangrove objects using unsupervised classification, before analysing mangrove density using the NDVI formula. The results show that the mangrove forest area in 2020 was 1,269.20 ha, with an accuracy rate of 83%. Mangroves were found on the deepest or most curved coastline of the Benoa Bay area, on enclosed waters. This distribution follows the river network in the lower reach, which has thick deposits and is uninfluenced by large currents and waves. Based on the vegetation index analysis results, the mangrove forest area observed mainly had a moderate density, with a total area of 510.85 ha (40%), followed by high density (413.15 ha/ 33%) and low density (340.51 ha/ 27%)

Spatial patterns of soil characteristics and soil formation in the transitional landscape zone, central part of Bogowonto Catchment, Java, Indonesia

Die vorliegende Forschungsarbeit fokussiert die Bodeneigenschaften und Bodenentwicklung in der Übergangszone des Sumbing Quartär-Vulkansystems, des Menoreh Tertiär-Vulkansystems und des tertiären Halang Systems. Die Forschungsziele bestehen in der Identifikation der räumlichen Muster von Böden, der Charakterisierung der Substrate der Böden und der Charakterisierung der Bodenentwicklung im Forschungsgebiet. Die Arbeit soll folgende Beiträge zur Überbrückung von Wissenslücken leisten: (i) eine Berücksichtigung der Beziehungen zwischen Pedogenese und Landschaftssystem; (ii) Klärung des Einflusses des Reliefs auf die Entwicklung von Bodenprofilen; (iii) Charakterisierung des Einflusses von Hangoberflächenprozessen auf die Entwicklung von Bodenprofilen von hügeligen Gebieten; (iv) Berücksichtigung von Hangmaterial als Substrat der Bodenbildung; (v) der Einfluss von menschlicher Nutzung auf Boden eigenschaften und Bodenumlagerungen.<br /><br />Die verwendete Erhebungsmethode wurde durch Bodenbeprobungen unterstützt. Die entnommenen Proben wurden sowohl qualitativ bereits im Feld als auch quantitativ im Bodenlabor untersucht. Die Probenentnahme erfolgte im zentralen Teil des Bogowonto Einzugsgebiets. Das Einzugsgebiet wurde ausgewählt, da es verschiedene Faktoren und Prozesse abbildet die signifikanten Einfluss auf die Bodenentwicklung im Untersuchungsgebiet haben. Als Methode der Bodenbeprobung wurden Zielstichproben gemäß soil-scapesystem gewählt. Insgesamt wurden 43 Peda ausgewählt, basierend auf den Landschafts-Segmenten. 16 der Peda wurden für die Analyse von Verwitterungsböden herangezogen, 27 für eine Analyse umgelagerter Böden, unterteilt nach der Morphodynamik in 11 (durch Rutschung) und 16 (durch den Menschen). Die durchgeführten Analysen der Bodeneigenschaften umfassten morphologische, physikalische, chemische und mineralogische Analysen, dem Soil Survey Laboratory Methods Manual (2004) folgend. Daneben wurden auch Verfahren zur Abschätzung der Bodenprofilentwicklung angewendet: das Verhältnis der organischen Materie (SOM) und des prozentualen Anteils von Ton. Dabei wurden deskriptive statistische Analysen zur Beschreibung der Bodeneigenschaften verwendet. Die räumlichen Besonderheiten der Landform wurden vereinfacht dargestellt auf Basis einer Raumanalyse.<br /><br />Die Ergebnisse zeigen dass die Bodenvariationen in der Landschafts-Übergangszone nicht ausreichend diskutiert werden kann nur auf der Grundlage des Catena-Konzepts, was sich begründet in den nur zweidimensionalen Beschreibungen von Böden entlang des Hang-Transekts, die das Konzept anbietet. Um aber die Bodenvariationen im Untersuchungsgebiet zu erklären, bedarf es eines Konzepts, das die Landschaftskonfiguration einschließt. Hier ist das soil-scape Konzept besser geeignet. Das Untersuchungsgebietumfasst kurze Abschnitte von Hängen mit der Möglichkeit diverser Böden entlang der Neigung, aufgrund des komplexen Reliefs sowie der intensiven Hangoberflächenprozesse. Folglich gibt es keine sequentiellen Muster von Bodeneigenschaften entlang der oberen, mittleren und unteren Abschnitte des Studiengebiets auf regionaler. Ebene, begründet durch die nicht-sequentiell von den oberen zu den unteren Abschnitten gelegte Reliefkonditionen in der Landschafts-Übergangszone. Die Bodenvariationen im Studiengebiet sind mehr beeinflusst von den Typen der Substrate und der Reliefkonditionen als von den Hangpositionen.<br /><br />Die vorliegende Studie zeigt, dass es nicht ausreicht, für die Bodenbildung nur die Verwitterung des Ausgangsgesteins zu betrachten, sondern auch andere Prozesse wie Umlagerungen durch Rutschungen und den Menschen sowie hydrothermische Veränderungen im Ausgangsgesteins. Üblicherweise wird angenommen, dass Bodenbildung immer mit Verwitterung vom Ausgangsgestein beginnt. Es wurde allerdings herausgefunden, dass an einigen Stellen die Bodenbildung durch hydrothermale Effekte auf Ausgangsgestein kontrolliert wird. Insgesamt können sich Verwitterungsböden aus verschiedenen Materialien wie verwittertem Muttergestein, verwitterter Vulkanasche und verändertem Ausgangsgestein bilden. Die Unterschiede der verwitterten und der veränderten Ausgangsgestein werden ausführlich beschrieben anhand von Farbe, Textur, Kationen Austauschkapazität (CEC), Tonminerale, Basenkationen, Basensättigung und organischer Substanz (SOM). Böden, die auf verwittertem Ausgangsgestein entwickelt sind habe bräunliche bis gräuliche Farbe, während Böden aus verändertem Ausgangsmaterial rötlich bis orange sind. Erstere weisen weniger als 30% Tonanteil auf, während Letztere deutlich höhere Tonanteile haben bis maximal >60%. Böden auf verwittertem Substrate haben mittlere bis hohe CEC-Werte, 20-70 me/100gr und haben in der Feinfraktion Illit und Montmorillonit. Der Illit wird durch teilweise Substitution von Aluminium und Silikat durch schwache K-Bindung zwischen den Alumino-Silikatschichten dominiert. Der Montmorillonit hat schwache Sauerstoffbindung, die leicht zu ersetzen ist. Bei der Bildung von Montmorillonit wird das Aluminium (Al3+) meist durch Magnesium (Mg2+) ersetzt. Diese Tonminerale sind austauschstark und führen zur Bindung der Kationen und damit zu einer hohen Basensättigung. Im Gegensatz dazu haben die auf verändertem Ausgangsmaterialien entwickelten Böden viel niedrigere CEC-Werte <10 me/100 gr aufgrund der Dominanz von Kaolinit sowie geringere Basensättigungen.<br /><br />In der untersuchten Landschaftsübergangszone sind beeinflussen Rutschungen die Bodenentwicklung maßgeblich, wobei hinsichtlich der Bodenvariabilität eine. Abtrags- und Akkumulationszone unterschieden werden kann. In der Abtragszone ist die Bodenentwicklung gestört, die Profile reduziert. In der Akkumulationszone wird die Bodenbildung ebenso gestört, jedoch durch die Überlagerung des ursprünglichen Ausgangsgesteins, so dass die Bodenbildung auf dem neuen Material wieder beginnt. Außerdem sind die meisten Böden im Untersuchungsgebiet durch verschiedene menschliche Aktivitäten beeinflusst, die zu unterschiedlichen Auswirkungen bei der Bodenentwicklung führen. Durch menschliche Aktivitäten, werden Bodeneigenschaften modifiziert, sowohl physisch als auch chemisch. Die Aktivitäten des Menschen zusammen mit denen der Rutschungen führen zu neuen räumlichen Verteilungen der Böden mit unterschiedlichen Profilentwicklungen.This research focuses on evaluating the spatial patterns of soil characteristics and soil formation in the transitional zone of Sumbing Quaternary Volcanic, Menoreh Tertiary Volcanic, and Halang Tertiary Structural systems. The objectives of this research are: to identify the spatial pattern of soils in the study area, to characterize the soil parent materials and the soils in the study area, and to evaluate the soil formation and the soil development in the study area. The knowledge gaps raised in this research are: (i) the relationship between soil formation and landscape system; (ii) the influence of relief in soil profile development and in soil formation cycle; (iii) the influence of slope surface processes in soil profile development of hilly areas;(iv) the contribution of slope deposit as soil parent material; (v) the anthropogenic influence on surface soils and its consequences for soil redistribution. <br />We applied survey method supported with soil sampling. We analyzed the samples both qualitatively in the field and quantitatively in the laboratory. The sampling area is the central part of Bogowonto catchment. The catchment area was chosen because the area have various factors and processes which are significant to influence the soil formation and the soil development in the study area. The soil sampling method applied on this field investigation was purposive sampling according to soil-scape system. There were totally 43 pedons selected based on landform segmentations. There were 16 pedons sampled for residual soils analysis. There were 27 pedons sampled for redistributed soils analysis; contained by 11 pedons of landslide deposit and 16 pedons of human induced-soil. We conducted soil properties analyses i.e. morphological, physical, chemical, and mineralogical for data analysis, followed the standard of Soil Survey Laboratory Methods Manual (2004). We also conducted quantitative assessment of the degree of soil profile development. Two ways were applied on this assessment: (i) Ratio of soil organic matter (SOM); (ii) Ratio of percentage of clay. We used descriptive-statistic analysis to interprete the soil properties data. We applied spatial analysis to simplify the spatial patterns of phenomenon in the landforms.<br />The results show that the soil variation in the transitional landscape zone is not sufficient to be discussed through the catena concept of single slope. It is because the catena concept only provides two dimensional descriptions of soils along the slope transect. However, to explain the soil variation in the transitional landscape zone needs a concept which describes the configuration and arrangement of a landscape. The soil-scape concept is better applied on explaining the soil variation in a transitional landscape zone. As the transitional landscape zone, the study area spatially consists of short sequences of hill slopes with the possibility of various soil parent materials along the slopes, complex reliefs, as well as intensive slope surface processes. Consequently, there is no sequential pattern of soil characteristics along the upper, middle, and lower parts of the study area in the regional scale. This is due to the fact that relief condition in the transitional landscape zone is not laid sequentially from the upper to the lower parts. The soil variation in the study area is more influenced by the types of soil parent materials and relief condition, rather than the slope position. <br />The other results show that the soil formation in this study does not only consider the weathering of parent rock to perform the soil parent materials. It also considers the other processes supporting the soil parent materials deposition such as hydrothermal alteration, burial process, and anthropogenic process. It is commonly found that the soil formation is always started by parent rock weathering. However, a contrary occurrence is found that in some location the soil formation is also controlled by the parent rock alteration due to hydrothermal effect. Overall, the residual soils may develop from various soil parent materials such as weathered parent rock materials, weathered volcanic ash materials, and altered parent rocks materials. The differences of weathered parent materials and altered parent materials are strongly described on the properties of color, texture, CEC, clay type, cation bases, base saturation and SOM. Soils developed on weathered parent rock materials have brownish to grayish color, whereas, soils developed on altered parent rock materials have reddish to orange color. Texture of soils developed on weathered parent rock materials show less than 30% of clay content, whereas, texture of soils developed on altered parent rock materials show much higher clay content, at most > 60%. Soils developed on weathered parent materials have medium to high CEC value that is 20-70 me/100gr indicating the clay type of illite and montmorrillonite. The illite is dominated by partial substitution of aluminium and silicate due to weak K-bonding among the alumino-silicate layers. However, the montmorillonite has weak oxygen bonding that is easily substituted. In the formation of montmorillonite, the alumino (Al3+) is mostly substituted by Mg2+. Consequently, these clay types result in the excess negative charge, and thus cause the high capability of exchanging and binding cations leads to the high base saturation. In contrast, soils developed on altered parent materials have much lower CEC value that is < 10 me/100gr indicating the clay type of kaolinite. This low CEC is followed by a fewer amount of exchangeable cations because the kaolinite is dominated by hydrolysis that cause the replacement of cation bases by the ion H+. Consequently, this type of clay results in low capability of exchanging and binding cations causing low base saturation. <br />As the transitional landscape zone, landslides are also the influencing factor for soil formation and soil development. The effect of landsides in soil variation are focused on two zones i.e. depletion zone and accumulation zone. The soil development is cut off in the depletion zone of landslide. On the other side, the presence of landslide deposit on the slope surface is able to interrupt the influence of underlying weathered parent rock in soil development. The landslide deposit may bury the former soil profile in the deposition area, and bring about the new soil formation. Also, most of soils in the study area have been influenced by different types of human activities that generate different responses in soil development. Human activities are able to modify the soil characteristics both physically and chemically. The activities of human together with landslide are also able to redistribute the soils and interrupt the soil profile development.eingereicht von Nur Ainun Harlin PulunganAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZusammenfassung in deutscher SpracheUniversität Innsbruck, Dissertation, 2016OeBB(VLID)151573

Arrangement of Agricultural Reservoir Along Rill Erosion: Case Study in the Sumbing Volcanic Landscape, Java, Indonesia

Background and research aims: Most of volcanic landscapes on Java, Indonesia, are increasingly being used for agriculture. As a consequence, high rate of soil erosion due to agricultural cultivation cannot be avoided. Agricultural reservoir is one of methods to maintain soil loss due to erosion. Most research to date, however, have been based on the function of the reservoirs rather than on the arrangement of the reservoirs which are usually locally specific. Thus, an evaluation of the arrangement for agricultural reservoir becomes a crucial innovation. This study was aimed at examining the effectiveness of agricultural reservoir arrangement along rill erosion in reducing runoff volume as well as erosion rate, and increasing sediment trapped. Methods: The research was conducted using the field survey method at a key sampling area by considering the dominant relief and land cover on the volcanic landscape of the Sumbing Volcano. Data collected includes soil properties (texture, organic matter, porosity, soil pore distribution, permeability, and soil infiltration rate), runoff discharge, runoff volume, and sediment delivery. Research started by determining the points for placing the agricultural reservoirs along the rill erosion and continued with field and laboratory measurements. Results: Our results showed that placing agricultural reservoirs along the rill erosion effectively reduced erosion by 99.97%. Consequently, the erosion rate was only 5.5 × 10 −4  ton ha −1 . The effectiveness of agricultural reservoirs in reducing runoff volume and sediment delivery was 99.72% and 94.15%, respectively. Conclusion: Agricultural reservoirs that are placed along the rill erosion effectively trap sediment and reduce runoff so that erosion rates decrease. Implications for conservation: Placing agricultural reservoirs along rill erosion can improve the effectiveness of reservoirs in decreasing the erosion rate. This strategy helps reduce runoff and sediment to maintain the productivity of agricultural land. Finding a suitable strategy for the evaluation of erosion and sedimentation processes has important implications for soil and water conservation

LANDSLIDE RISK MANAGEMENT BY MEANS OF PROPOSED LAND USE IN GINTUNG SUB-WATERSHED, PURWOREJO REGENCY, CENTRAL JAVA PROVINCE, INDONESIA

The research was conducted on Gintung sub-Watershed. Gintung sub-Watershed is located among three districts: Loano District, Purworejo District, and Kaligesing District in Central Java Province. Gintung sub-Watershed is one of areas frequently suffered by landslide hazard. This research is aimed to manage landslide risk in the study area. Land allocation based on risk levels is proposed to provide the management of landslide risk. Three methods were applied in this research. First, statistic-probabilistic method was applied to obtain landslide susceptibility level of the study area. Multivariate statistic was used in this step. Logistic regression model was executed as the statistical approach. Slope, landform, soil, geology, land use, and aspect were the variables which were used in this analysis. Second, questioner survey was done to obtain vulnerability level of the elements at risk in the study area. Settlement and road network were the elements at risk which were analyzed in this step. Stratified-random sampling was applied on vulnerability assessment. Third, risk matrix was applied to obtain the risk level of landslide in the study area. The result of this research showed that 59.4% susceptibility level of landslide in Gintung sub-Watershed is categorized into moderate level. Probability of future landslide in the study area is greater than 0.6 respectively. Logistic regression equation stated that land use is the most controlling factor of landslide in the study area. Vulnerability level of settlement in the study area is categorized into moderate level. Vulnerability level of road network is categorized into high level. Based on the risk matrix, landslide risk level in the study area is categorized into moderate level. As a consequence, according to landslide risk levels in the study area, the proposed land uses are to limit settlement expansion in very steep slope area, to reduce garden uses through changing into dryland agriculture in flat up to undulating area and changing into bush and shrub in slightly steep up to steep slope area

The Ecological Perspective of Landslides at Soils with High Clay Content in the Middle Bogowonto Watershed, Central Java, Indonesia

The clay layers at hilly regions in the study area were very thick. The presence of very thick clay caused several difficulties in terms of environmental management, particularly in reducing georisk due to landslide. However, initial observations proved that areas of active landslides had better vegetation cover. The objective of this study was to find out ecological roles of landslides in livelihood in the Middle Bogowonto Watershed. The ecological roles of landslide were examined through field empirical evidences. Texture, bulk density, permeability, structure, and index plasticity were conducted for analyses of soil physical properties. Stepwise interpretation was made using 1 : 100,000–1 : 25,000 Indonesian topographic maps and remote sensing images of 30 m–<10 m spatial resolution. The results showed that landslides formed three landform zones: residual, erosional, and depositional zones. The area that did not slid, the residual zone, had massive soil structure and very hard consistency. Crops cultivated in this zone did not grow well. In the areas of active landslide, the environmental conditions seemed to be more favorable for living creatures. The landslides resulted in depositional zones with gentle slopes (4° to 15°), higher water availability, and easier soil management. The landslides also acted as the rearrangement process of landforms for better living environment

The Ecological Perspective of Landslides at Soils with High Clay Content in the Middle Bogowonto Watershed, Central Java, Indonesia

The clay layers at hilly regions in the study area were very thick. The presence of very thick clay caused several difficulties in terms of environmental management, particularly in reducing georisk due to landslide. However, initial observations proved that areas of active landslides had better vegetation cover. The objective of this study was to find out ecological roles of landslides in livelihood in the Middle Bogowonto Watershed. The ecological roles of landslide were examined through field empirical evidences. Texture, bulk density, permeability, structure, and index plasticity were conducted for analyses of soil physical properties. Stepwise interpretation was made using 1 : 100,000–1 : 25,000 Indonesian topographic maps and remote sensing images of 30 m–<10 m spatial resolution. The results showed that landslides formed three landform zones: residual, erosional, and depositional zones. The area that did not slid, the residual zone, had massive soil structure and very hard consistency. Crops cultivated in this zone did not grow well. In the areas of active landslide, the environmental conditions seemed to be more favorable for living creatures. The landslides resulted in depositional zones with gentle slopes (4° to 15°), higher water availability, and easier soil management. The landslides also acted as the rearrangement process of landforms for better living environment