Sand dune in Parangtritis Village has a speciality of being formed in humid climates (tropical). The initiation of Barchan Sand Dune as a new tourism based on eco-tourism has to consider many aspects to maintain sustainability of sand dune. It needs some information on economic valuation to determine the capacity of tourism objects as a consideration of sand dune's sustainability. The purpose of this research is to know the projection of Barchan sand tourism's feasibility until 2045. The research method is the economic valuation approach by calculating Nett Present Value (NPV) as the analysis (cost) and the benefit earned by Barchan Sand Dune Tourism. The method of economic valuation is chosen because it is able to convert ecosystem services into currency value (IDR) so that it can be a valid comparator. The hypothesis in this study states that the feasibility of Barchan Sand Dune Tourism will increase until certain year, but the increased feasibility will cease in a certain year and decrease in the following year. The results are obtained based on the calculation of Nett Present Value (NPV), it shows positive value so that Barchan Sand Dune Tourism is feasible to continue until 2045 with estimated profit reached IDR648,000,000. The calculation results show a decrease in the level of tourism efficiency in 2017. The level of efficiency can be increased again through management optimization based on the characteristics of the tour, which are something to do, something to see and something to buy at Sand Dune Barchan.

The Upper Belik watershed is a river that flows in Special Region of Yogyakarta. Land use in this watershed is dominated by settlements. The development activities by the human can cause river pollution if there are no maintenance and monitoring retated to their waste. The study aims to determine the waste load and capacity of the BOD. The descriptive quantitative with spatial analysis is used. The determination of the sample is by dividing the study area into five segments based on variations in pollutant sources and drainage flow directions. Water sampling and river morphological measurements were carried out purposively, water quality taken by grab sampling. Data are processed using the Water Quality Analysis Simulation Program (WASP). The results showed that Belik River could not accommodate waste loads. Segment one has to reduce 22,41 kg/day BOD, while the second segment does not need to reduce the load. Segment three must reduce as much as 5,73 kg/day, segment four by 35,81 kg/day and segment five by 61,16 kg/day. Reducing the waste load can be done by reducing the pollution load that flowing to the river.