Impact of land use and socio-economic changes in water catchment area on total suspended solid (TSS) in Lake Toba

Abstract

Changes of socio-economic and land use in the water catchment area are factors that affect the water quality of a lake. This study quantified the impact of socio-economic factors and the dynamics of land covers of Lake Toba water catchment area on the total suspended solid (TSS) parameter, one of the parameters in water quality indicators. Statistical analysis was run by using multiple linear regressions. Parameters observed were TSS, socioeconomic related data and land use in Samosir, Tobasa, Simalungun, Dairi, Humbang Hasundutan and North Tapanuli Regencies in 2008, 2012 and 2016. The results indicated that the water quality of Lake Toba was slightly polluted in 2016 and in 2017. Based on the regression analysis, it was found that some factors significantly affected the concentration of TSS, namely shrubland and dryland farming at 99% confidence level; the number of populations, Location Quotient (LQ) for dry land paddy field and soybean production at 95% confidence level; and settlement land area, geographic population density, LQ for rice and corn production at 90% confidence level. Managing shrubland through a land rehabilitation program and encouraging a rotational cropping system are recommended strategies to manage the increasing TSS in the Lake Toba.