Indonesian Journal of Geography
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a deterministic model for predicting water yield from two different watersheds
No full textThis study was conducted in Pogung-Code sub watershed and Pulo-Opak sub watershed from 1993 to 2002. A deterministic model developed by Haan (1972) was used to determine the amount of water yield from watersheds. The model consists offour parameters, namely: (0 maximum rate of seepage from the soil water zone in mm per day (S), (ii) maximum soil moisture less readily available for evapotranspiration in mm (C), (iii)fraction ofseepage from the soil water zone that becomes runoff(F), and (iv) maximum infiltration rate in mm per hour (f.).The inputs required by the model were the daily rainfall and the estimated potential evapotranspiration which was computed using Penman method. Streamflow records for 10 years of Pogung-Code sub watershed (2,801.77 ha) and Pulo-Opak sub watershed (4,856.37 ha) were used to test the validity of the model. The parameters obtained for Pogung-Code sub watershed were: S = 0.70 mm per day, C = 112.32 mm, F = 0.63, and- 5.38 mm per hour, meanwhile for Pulo-Opak sub watershed were: S = 2.33 mm per day, C = 86.72 mm, F --- 0.26 and f = 5.68 mm per hour.The final test of the adequacy of the model lay in a comparison of observed and simulated runoff The comparison showed that the observed and simulated runoff values are not significantly different. This was based on the results obtained from statistical measures to test the model. The model did a better simulation in the smaller watershed (Pogung-Code sub watershed) than in the larger one (Pulo-Opak sub watershed)
Misconception Of Run-Up Definition And Its Implication To Tsunami Risk Assessment A Case Study In Pacitan Coastal Area, Indonesia
No full textThis article aims to build the similar understanding of run-up concept and to review the "map of t,'}iinami risk analysis in Pacitan" released by Balai Pengkajian Dinamika Pantai (BPDP)-BPPT Indonesia. We also propose similar understanding of risk definition related to the natural hazards, such as tsunami. The investigation used comparison method between 2 maps, i.e. tsunami risk map by BPDP and our tsunami risk map. Based on the comparison result, we found a misconception of rim-up in the tsunami risk map produced by BPDP. There is no differentiation between run-up and water-height over the land. It should be revised to avoid it from the incorrect rim-up definition. We also found if it was also mentioned as a "map of t.\imami risk analysis" while the analysis result was not performed in that map. Therefore, it is necessGlY to understand the run-up concept and risk concept first prior to map those phenomena
ASSESSING THEHYPERSPECTRAL REMOTE SENSING DATA TO DIAGNOSIS CROP VARIABLES MODEL IN TROPICAL IRRIGATED WETLAND RICE
No full textCanopy spectral measureme~t using ground-based hyperspectral r;leviceand rice crop variables such as leaf area index (LAI), leaf dry weight (LDW) andSPAD values were done periodically during growth season with involving threerice cultivars (Pandanwangi, Ciherang and IR Jumbo) ahd four nitrogenapplication levels (NO,N80, N92 and NI03 kg/ha). Thestudy is directed to exploreall possible waveband combinations tested in reflectance of vegetation indices(VIs) and to develop a predictive model of relation between hyperspectral-basedvegetation indiceswith rice crop variables. .Analysis of all possible two-pair waveband combinations used in VIs wasinvestigated with 6,786 combinations to gain optimal waveband attributed to cropvariables. To develop.efficient and accurate model, various multivariate regressionmodels were examined with ten-fold cross validations. Accuracy validation ofpredicted model was performed using reflectance and FDR, NDVI, RVI, RDVI andSA VI data. Validation of predictive model using flJR implied better accuracy toestimate LAI using whole season data (R2=0.856). Meanwhile, the model usingSA VI denoted highest values (R2=0.852)for predicting LAI While the validation ofpredictive model using RVI implied the highest values (K=O. 797) for predictingLDW. Moreover, the test of predictive model using SAVI indicated the highestvalue (R2=0.658) for predicting SPAD values. According to overall validationusing VIs, it seems that RVI has the best accuracy to validate the predictive modelof LAI than those of LDW or SPAD values. Meanwhile, the most significant of K tovalidate the predictive model was obtained on FDR data with R2=0.859for LA
CLIMATE S ROLE IN CHANGING THE FACE OF THE EARTH AND THE SPATIAL CONFLICT PROBLEMS: A PRELIMINARY STUDYON THE CIMANUK WATERSHED
No full textThe increasedglobal climate directly affects theface of the earth. In additionto result in shifting of season and extremeweather, the relatively rapid changein temperaturebeing climate element also gives impact on intensity of geomorphologyprocess (weathering, erosion, sedimentation). This paper describes how theescalated climate affects the process 'of weathering and erosion as well as changein delta mainland size and its contribution to the emergence of spatial conflict.DAS Cimanukwas selected as the study case area. The escalated air temperaturefor a long period directly escalates the acceleration of rock weathering, which inturn accelerates the erosion of weathered rock due to rainfall to be sedimentmaterial through erosion process. During period of 1963 - 2002, Cimanuk deltaarea enlarged more than 350.000 m2/year. This new land, which is formed byweathering and erosion processes in the Cimanuk River Basin through peels ofland surfacepredicted to be averagely more then 10 em/year. In the last, the newlandformed by geomorphologic processes triggering the new source of conflictpotentially
A LOCAL SPATIAL DATA INFRASTRUCTURE TO SUPPORT THE MERAPI VOLCANIC RISK MANAGEMENT: A CASE STUDY AT SLEMAN REGENCY, INDONESIA
Get PDFThis research aims to implement an application of a Local Spatial DataInfrastructure (SDI) for evacuation planning of Merapi Volcano disaster. Theprocesses, problems and information flows in evacuation planning were examined.Geo-collaboration Portal was customized in order to provide spatial resources fordecision makers. It is equipped with usable maps presentation and interaction toolsto support collaborative decisions. User group assessment was carried out toevaluate usability of the application. The evaluation results showed thatcollaborative portals on top of a local SDI can facilitate effective decision makingprocess and improve coordination among involved stakeholders in thecontext of disaster preparedness and mitigation. Several aspects need to beconsidered in order to achieve a functional local SDI e.g. availability and qualityof the spatial data, establishment of local regulations and standards, developmentof metadata, and strengthening capable human resources
A PRELIMINARY INVESTIGATION ON CHANGING TEMPERATURE MAXIMA-MINIMA DEVIATION (TMIN-MAX DEVIATION) IN INDONESIA
Get PDFWhile the immediate impacts of climate change have been widely discussed,there are only few researches on climate change revealing its effect to temperatureamplitude. Changing temperature amplitude will hamper metabolism process,which in turn will decrease productivity and, even, cause the extinction of certainorganism species. This research will expose the changing temperature amplitude (Tminmax)including its trend pattern in Indonesia. The adoption of trend analysis methodand comparison analysis to the values of temperature amplitude in 60 AWS stationfrom 1980-2007 indicates upward trend of annual mean temperature with shortertemperature amplitude. This shorter temperature amplitude is characterized byannual mean temperature maxima increase less than the rise of annual meantemperature minima. Data analysis finds indication, i.e. the more eastward direction, thegreater difference of average Tmin-max deviation. Yet, this research fails to show whatfactors contributing to the changing temperature amplitude. More in-depth researchof these factors at ecological scale will be necessary as crucial part in determiningadaptation programs to this on-going climate change phenomenon
THE ROLE OF VEGETATION COVER AND CATCHMENT CHARACTERISTICS ON BASEFLOW IN BALI ISLAND
Get PDFStudies of the role of combined vegetation cover and catchment characteristics on base flowcondition are required to address the controversy of correlation between vegetation andhydrological properties. Objectives of the research were: 1) to assess the hydrological role ofvegetation on baseflow condition; and 2) to study the influence of vegetation cover in relationto catchment characteristics on the baseflow. Field survey, digital filter method, remotesensing technique, and statistical analysis were used to derive and assess the correlationamong variables. Results of the research were: 1) a negative significant correlation betweenvegetation cover and baseflow recession coefficient, despite the fact that it is not a singlefactor and related to various catchment characteristics; 2) vegetation cover is not a singlefactor in determining the baseflow characteristics, since it also involves drainage density andinfiltration rate
CONCEPTUALIZATION OF URBANIZATION STRUCTURE AND CLIMATE CHANGE IN LAGOS, NIGERIA
Get PDFUrbanization is synonymous with environmental challenges. In developing countries, thechallenges have assumed higher dimensions proportionally due to multifarious issues of rapidchanges in the environment, due to development, through population growth andindustrialization, and accompanied by all kinds of pollution such as air pollution, wastedisposal, land use degradation, and vehicular pollution as the resultant effects of man’sinteraction with the environment. The main characteristic effect is the raised temperature of thecity centre (UHI) leading to excessive energy use for cooling and putting urban population atgreat morbidity and mortality risks. This paper literally explores the conceptual framework ofinteraction between urbanization structure and understanding social impacts of climate changeand variability for the evaluation of strategies in the urbanized environment that might serve asadaptive response to climate change. The urbanization structure that affects Lagos state isdiscussed in relation to the location of the city, the size, the population density, urbangeometry, thermal property, air pollution, land use pattern, wind speed and anthropogenicactivities. The study revealed that climate change is posing increasing challenges for citiesplacing greater stress and impacts on multiple social and biophysical systems, including urbaninfrastructure, water and energy demand simultaneously, followed by a strong global trendtowards urbanization of urban poverty. The study concluded that climate change has impactedgreatly on virtually all the socio-economic aspects of man
LAND USE MODEL FOR BUILDING BASED ON CARRYING CAPACITY OF CITY LAND (CASE STUDY: PALU CITY)
No full textThis study aims to model the growth trend of the extent of land use for building based on thecarrying capacity of land in Palu city which is known as Bay City in accordance with theprediction of time. Methods of research were carried out with the approach of spatial andquantitative methods. The results show that Palu city as Bay City has the characteristics ofurban land that is quite specific to the protected area. There is still available land forbuilding i.e.: ± 13.151,13 ha (34.74%) with a growth rate of land use for building in thefuture 2.72% per year, area of cultivation will be fully filled in the year 2056 with thecapacity of 1.052.730 people. Carrying capacity of land in Palu city until the year 2056 hasnot exceeded the threshold, either by the land consumption per capita or by the level density
Urban environment assessment: special reference to terrestrial and aerial photographic approaches
No full textThe following discussion particularly stresses the techniques or research methodologies concerned with urban environment assessment. Given the fact that monitoring the quality of the urban environment is prime, some practical approaches to that problem are seriously needed. Due to the complex nature of the urban environment in terms of the elements, interrelationships of elements, and dynamic nature of their interactions, the author devises a model in the form of a combination approach to assess the urban environmental condition.The variety of urban environments reflects the social, economic, cultural, political, technological and demographic background of the nation and accordingly there should be a wise selection of the applied techniques and the environmental criteria used for assessing the urban environmental condition.The combination approach is an integration of terrestrial and aerial photographic approaches. Since each of the aforementioned approaches has its own weaknesses, the combination approach is expected to cover those weaknesses and can give more effective, accurate and reliable data on the urban environmental assessments