Pengaruh Perubahan Tata Guna Lahan Terhadap Puncak Banjir Das Winongo Di Selatan Jembatan Kretek (Impact Of Land Use Change On Flood Peak Winongo Watershed In South Of The Kretek Bridge)

Abstract

Land use in the watershed Winongo each year has increased. The increasing of population and various human activities indirect land use change previously open land into smaller plots. It indirectly affects water runoff that occurs when it rains with high itensitas. The inability of the land to absorb water due to changes in land use will affect the increase in water runoff. The purpose of this study was to compare the effect of land use in 2002, 2007 and 2013 to the peak of the floods in the Watershed Winongo.Analysis of land use change variables done through mapping technique based on interpretation of Landsat TM in 2002, 2007 and 2013. The result is a map of land use in 2002, 2007 and 2013. Changes in land use in these years are interpreted through the overlay technique with the help of software ArcGIS 10.3. Unit hydrograph obtained from the analysis of synthetic unit hydrograph Soil Conservation Service (SCS). Rainfall data were obtained in the form of daily rainfall that need to be done in the temporal distribution (hourly). Calculation of daily rainfall distributed design using Alternating Block Method (ABM). Kirpich method used to calculate the duration of rainfall is needed method (ABM). Results of the analysis showed improvement of flood discharge that occurs in the watershed Winongo. Flood peak discharge plan with ABM rainfall distribution in 2002 amounted to 184,642 m3 / sec, the year 2007 amounted to 185,841 m3 / sec and in 2013 amounted to 189,530 m3 / sec. Value Curve Number composites from the 2002, 2007 and 2013 obtained at 78.958, 79.075, and 79.431. CN value annually increased if CN is equal to 100, the impervious surface.