Rainfall Variability in Gunungsewu Karst Area, Java Island, Indonesia

Abstract

Karst area is highly susceptible to changes to climate parameters. One of the parameters is rainfall variability. In addition to shaping the condition of water resources, rainfall in the Gunung Sewu karst area determines the nature of crop and livestock of the agriculture sectors―the local population's main economic activities, warranting the significance of the rainfall variability studies. Rainfall variability in karst areas also affects disaster conditions such as drought and floods. However, due to insufficient meteorological data in quality and quantity, there has been no rainfall variability studies conducted in this locality. The research intended to analyze rainfall variability in the Gunung Sewu karst area in 1979‒2013 by utilizing rainfall predictions from satellite images that many scholars had tested in different locations and recognized as having good quality. In the analysis, mean monthly rainfall was calculated, and the trends of annual rainfall and average rainfall intensity, dry and rainy seasons, the number of rainy days, and the effect of ENSO (El Niño Southern Oscillation) on rainfall were analyzed. The research data were 35 years of daily rainfall records derived from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR). The analysis results showed that the mean rainfall, number of rainy days, and rainfall intensity had an increasing trend. Also, El Niño quantitatively influenced the rain in the Gunung Kidul karst area.

Temporal Variation of Phosphate Contamination In Tropical Epikarst Springs, Gunungsewu Karst Area, Indonesia

“…The multitemporal analysis in this research took seasons into account, given that rainfall is the main factor influencing variations in the spring's hydrological conditions. In the Gunungsewu Karst Area, the rainy season starts in October and ends in March, whereas the dry season lasts from April to September [25]. Figure 2 shows four charts illustrating the correlations between phosphate, flow discharge, and rainfall in different seasons.…”

“…Nevertheless, both R-values indicated weak correlations,suggesting that the three pollutants did not originate from the aforementioned sources. According to previous studies by Cahyadi et al [7] at the Selonjono Spring and Adji et al [30] in the Seropan Underground River in the Gunungsewu Karst Area, phosphate comes from agricultural fields, sulfate from domestic waste (gray water or detergent), and nitrate possibly from fecal matter. Agricultural practices apply fertilizers that leave residues of phosphate in the soil, and Loganathan et al [31] confirmed that the groundwater's phosphate content is likely to increase with the added fertilizers.…”

“…Both have different roles but are comparably significant for this system. Epikarst is located in the uppermorst zone and has high permeability and porosity, which is essential for creating a suitable water storage medium [7,8]. Epikarst is also important for feeding of underground rivers even during very long periods of drought, and regulates water infiltration, storage, and evapotranspiration in the region [9][10][11][12].…”

Groundwater Chemistry Characterization in the South and Southeast Merapi Volcano, Indonesia

“…The volcanoes in Indonesia are unique compared to those found in other parts of the world. Cahyadi et al (2021) stated that these are usually located on the Indonesian Maritime Continent, and it affects the high rainfall triggered by Monsoons, El Niño Southern Oscillation (ENSO), and Inter Tropical Convergence Zone (ITCZ) (Aldrian & Susanto, 2003). Döll and Fiedler (2008) reported that the high tropical rainfall impacts the potential for groundwater recharge, especially in volcanoes.…”

Preface: The 4th International Conference on Environmental Resources Management (ICERM) 2021

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Landscape is very dynamic [1,2,3]. In line with the development of an increasingly climate change [4] and high population, the dynamics of the landscape have also changed due to an increase in the intensity of the population in utilizing land. The condition of the corona virus pandemic since the beginning of 2020 has resulted in two impacts to the environment.

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