JOGJAKARTA (KU) – Lecturer in Geography and Environment Study Program, Faculty of Geography Universitas Gadjah Mada (UGM), Langgeng Wahyu Santosa, S.Si., M.Si., on Friday (6/8), successfully earned doctorate degree for his dissertation on aquifer (groundwater layer) along the coastal regions of Kulonprogo Regency, Yogyakarta.
The man born in Klaten on 10 July 1972, who graduated cumlaude, studied the genesis of land shape and its effect on system formation and aquifer pattern based on aquifer hydrostratigraphical reconstruction. He said that the quarter land in the western coastal region of Kulon Progo is formed by marine main process (Pliocene-Pleistocene), followed by eolian and fluvial processes (Holocene).
“Geomorphological process in the past has left a clear mark on the current shape of land. The genesis of the land has affected the aquifer hydrostratigraphical formation in coastal regions,” said the husband of Reny Ariani, SIP.
In addittion, genesis of the shape also affects the shape of free groundwater evolution that is showed by process variations of free groundwater hidrogeochemical specific in every shape. Meanwhile, the effect of genesis on the shape of area in Kulon Progo is known to be the result of what happened in the past, known from lime stone formation in Sentolo as activity of coral reefs from the shallow sea zone in calm seawater and the formation of morphology patterns of slopes and ridges of Sentolo hills that resemble gulf and peninsula patterns.
Furthermore, there is the sediment in the form of marine clay lenses containing fossils of shallow sea molluscs and peat layer resulted from decayed swarm plants, in addition to groundwater traps from brackish water to salt water from the basin of former lagoons.
To reporters, Langgeng said that his research done along the Progo River to Bogowonto River in Kulon Progo can be utilised to know the position of groundwater layer, predicting where the groundwater bodies are, to know the nature of groundwater, to be made recommendations for the local community whether it can be consumed or not. “The unique nature of good and bad groundwater can be made recommendation if the water is consumable or not,” said the 1252 doctoral graduate from UGM.
He said that consumable groundwater is located in fluviomarine areas, beting gisik compound, Swale and sand dunes. These include the areas of Karangwuluh, Janten, Kebonrejo, and Kalidengen, Temon sub-district. Groundwater in the southern region is very risky to be consumed if the groundwater is fetched continuously. The groundwater will be refilled by seawater. “If much sand is extracted, groundwater will run out and sea water will replace. If sand is added, the morphology will change and the water is disrupted, while the water is also used for agricultural purposes,” he added.
The exam in the auditorium of Faculty of Geography was attended by promoter Prof. Dr. Sutikno, and co-promoters Prof. Dr. Totok Gunawan, M.S., and Prof. Dr. Suratman, M.Sc. Panel of examiners are Prof. Dr. R. Rijanta, M.Sc, Prof. Dr. Sudarmadji, M.Eng.Sc., Dr. Ir. Heru Hendrayana, M.Sc., Dr. Slamet Suprayogi, M.S., and Prof. Dr. Bambang Prastistho, M.Sc.