The development of construction will affect work methods in construction, design and materials. Changes in design, materials and work methods in the construction of a construction project will affect the costs that must be incurred by the owner and the time required to construct a building. Conceptual cost estimation is needed as a reference or guide in determining the policies used to determine the amount of investment that must be implemented. Planning is the initial stage in construction development activities. Effective and efficient project planning is needed in carrying out a project. Along with the need for efficiency, the cost estimation model at the early stages of project planning must be accurate so that the results can be accounted for. This study aims to obtain an estimate of the structural cost of a shop house building with several span variations. Variations in the width of the shop house are 5 m, 6.67 m and 8 m. The research results obtained that the cost of the structure on the 8 m span is Rp. 2,352,485,387, the 8 m span is the span that has the largest cost compared to other spans. The difference between the span of 8 m and the span of 6.67 m and 5 m is Rp. 93,480,110 and Rp. 13,740,263, respectively. Based on these results it was concluded that the larger the span, the greater the costs required. This is influenced because there are differences in the dimensions and specifications of the structures used in each span.

Gadjah Mungkur Reservoir is one of the multipurpose reservoirs built by damming the flow of the Bengawan Solo River. The Gadjah Mungkur Reservoir has existed for a long time with the main purpose of controlling flooding, but over time, this reservoir is also useful as a hydropower plant, irrigation, and also to meet the raw water needs of Wonogiri City. The potential of the Gadjah Mungkur Reservoir itself in meeting the needs of drinking water is an essential function in the people’s life around the reservoir. Therefore, the expansion of the scope of providing drinking water can be used to develop the potential of the Gadjah Mungkur Reservoir. This coverage expansion was realized through the construction of the Wosusokas intake and transmission pipeline network to drinking water receiving areas, namely Wonogiri, Sukoharjo, Solo, and Karanganyar, with service coverage of drinking water access resepectively ±78,38, ±70,97%, ±81,85%, and ±70,97%. This study aims to analyze the water availability of the Gadjah Mungkur Reservoir with additional coverage for drinking water services. The method used is a simple reservoir routing calculation by processing secondary data obtained in the form of inflow, outflow, and reservoir storage characteristics. The results of the analysis show that elevation variations with the construction of the Wosusokas intake and transmission pipeline have an annual average of +132,56 m in 2017, with a reservoir storage volume reaching 216,27 MCM and +134,29 m in 2018, with a reservoir storage volume reaching 284,92 MCM. However, there are some elevation values that exceed +138,0 m, namely at February to March 2018. However, overall, the results of the analysis show that the Wosusokas construction can increase the potential utilization of the Gadjah Mungkur Reservoir without endangering the reservoir with water level fluctuations that can still be controlled and in accordance with the regulation of reservoir water level.