Wawat Sopiyan / 232008014 Penulis Hary Nugroho, Ir., M.T

Decreasing of soil surface in Jakarta has been indicated as a factor of rob flood in thoseDecreasing of soil surface in Jakarta has been indicated as a factor of rob flood in those area (Syarifah, 2002). This soil surface decreasing is very possibly happen in Jakarta because of the highly development of the city that cause the rapid suctioning of ground water and the mass of the construction that endured by soil surface (Quaxiang, 2001). The purpose of this research is to model the decreasing of soil surface in south Jakarta and central Jakarta by using a regression method. In hopes by this research we could describes the levels of the soil surface decreasing. Methods that used for this research is linear regression and polynomial regression for predict the soil surface decreasing in those area in year 2020 by using the elevation data in years 1978, 2005 and 2013 as the parameters. Result from this research shows that based on the polynomial regression in those area the soil surface decreasing is 14 meters with per years decrease 0.34 m/y. Meanwhile by the linear regression method, the soil surface decreasing is 6 meters with per years decrease 0.14 m/y. the conclusion from this research is the average soil decreasing in central Jakarta and south Jakarta from years 1978 to 2013 is 4.862 meters, with average decreasing 2.264 meters per year. From the linear regression calculation we can conclude that year 2020 the soil surface has average decrease as 2.704 meters, meanwhile in polynomial regression we can conclude that in year 2020 the soil surface has average decrease as 5.251 meters. area (Syarifah, 2002). This soil surface decreasing is very possibly happen in Jakarta because of the highly development of the city that cause the rapid suctioning of ground water and the mass of the construction that endured by soil surface (Quaxiang, 2001). The purpose of this research is to model the decreasing of soil surface in south Jakarta and central Jakarta by using a regression method. In hopes by this research we could describes the levels of the soil surface decreasing. Methods that used for this research is linear regression and polynomial regression for predict the soil surface decreasing in those area in year 2020 by using the elevation data in years 1978, 2005 and 2013 as the parameters. Result from this research shows that based on the polynomial regression in those area the soil surface decreasing is 14 meters with per years decrease 0.34 m/y. Meanwhile by the linear regression method, the soil surface decreasing is 6 meters with per years decrease 0.14 m/y. the conclusion from this research is the average soil decreasing in central Jakarta and south Jakarta from years 1978 to 2013 is 4.862 meters, with average decreasing 2.264 meters per year. From the linear regression calculation we can conclude that year 2020 the soil surface has average decrease as 2.704 meters, meanwhile in polynomial regression we can conclude that in year 2020 the soil surface has average decrease as 5.251 meters.