No abstract

Due to sand mining, the study objective is to assess water quality in the Progo River, Daerah Istimewa Yogyakarta Province. It is beneficial to evaluate the physicochemical parameters of the Progo River and to appraise water quality for drinking purposes based on the Indonesia Minister of Health regulation No: 492/ Menkes/Per/IV/2010. The physicochemical parameters used in this study included pH, EC, TDS, DO, SO4 2-, NO3-, and PO4 3-. The pH decrease is thought to be due to the opening of sand deposits around the river so that minerals such as feldspar, hornblende, and quartz dissolve and mix in water. The TDS increase was estimated due to the increase in the riverbed and bank erosion associated with sand mining at the mining and downstream sites. In addition, sand mining activities affect higher DO because bubbles aerate flowing water in fast-moving water as it churns over rocks and falls into hundreds of tiny waterfalls. Meanwhile, other parameters, such as EC, SO4 2-, NO3-, and PO4 3- are influenced by natural factors, such as seawater mixing and soil erosion. Almost all parameters are permissible for drinking purposes, except for Station 3 at the downstream which TDS and SO4 2-- values are.

Construction of Yogyakarta International Airport on Kulonprogo coastal areas can threaten the groundwater quality because it can cause seawater intrusion. The method in this study is by using a literature review. The purpose of this review is to investigate seawater intrusion prone areas around Yogyakarta International Airport based on a geological approach. The geological approach associated with seawater intrusion in the study site is a lithological characteristic. A lithological characteristic discussed in this study is the origin of the sand on Kulonprogo beach where the Yogyakarta International Airport is located. The elements used in the seawater intrusion test parameters are Na+, Ca2+, K+, Mg2+, CO3 2−, HCO3 −, Cl− and SO4 2−. A rise in Cl− was reported as suggesting the intrusion of seawater into the groundwater. But if only see the value of one of those elements, it cannot indicate seawater intrusion occurs in that area. The high element’s contents can arrive from the solution or weathering the lithological. This study is preliminary research, to assess seawater intrusion in the study site, it is necessary to conduct a groundwater geochemical test in the future.