22-27 September 2019
Trade Fairs and Congress Center (FYCMA)
Europe/Madrid timezone

RAPID ASSESSMENT METHOD FOR KARST CONSERVATION ZONE DELINEATION IN INDONESIA

Not scheduled
15m
Trade Fairs and Congress Center (FYCMA)

Trade Fairs and Congress Center (FYCMA)

Av. de José Ortega y Gasset, 201 29006 Malaga, Spain
Oral Topic 7 - Karst Hydrogeology Parallel

Speaker

Mr Afid Nurkholis (Karst Research Group, Faculty of Geography, Indonesia)

Description

In Indonesia, conflicts of interest between limestone mining and conservation zone in the karst area occurred frequently. The Ministry of Energy and Mineral Resources (ESDM) of Indonesian Republic had stipulated ESDM Ministerial Regulation Number 17/2012 concerning "Karst Conservation Areas". Based on this regulation, the protected karst area is a landscape that has hydrological functions and the uniqueness of eksokarst-endokarst characteristics. However, there is no fixed method for implementing the regulation in Indonesia. This research aims to propose a method for establishing karts conservation zones rapidly and precisely. The study area located in the Karst Karangbolong Area, Kebumen Regency, Indonesia. In this region the community depend on karst springs to meet their clean water needs, the main springs are Kali Sirah and Jumbleng. The research method used is water tracing, cave mapping, and field observations carried out for seven days. Injections of uranine and tinopal were carried out on several ponors/sinkholes that are estimated to be connected to both springs. Fluorometer GGUN FL-30 was installed in Kali Sirah Spring while GGUN FL-24 was installed in Jumbleng Spring. Charcoal bags were also installed on several springs around the study area. The field observations consisted of measurements of lineament direction and thickness of the epikarst zone which used to make 3D topography. Conservation zone area was delineated by observing the water tracing direction and 3D topography. Validation of the area was done by calculating the nomogram Todd.

Water tracing shows that Kali Sirah and Jumbleng have different hydrogeological systems despite their adjacent location. Kali Sirah Spring is recharged by the Pucung Sinkhole-Candi Cave-Jeblosan Cave system while Jumbleng Spring is recharged by the Banjiran Sinkhole. The conservation zone in Kali Sirah Spring has an area of 174 Ha which has a difference of 8% from the nomogram Todd (189.2 Ha). Meanwhile, Jumbleng has a conservation zone of 46 Ha which has a 5.5% difference with the nomogram Todd (48.7 ha). This study shows that water tracing and fields observation can be used to determine the catchment area of karst spring which is then declared as a conservation zone. This conservation zone is still general because it only considers instantaneous flow connectivity so that this zone can cover an extensive area. Further researches to detail the conservation zones can be done by forming a karst aquifers vulnerability map. Nonetheless, this research can be applied to examine karst conflict areas that require rapid solving.

Primary author

Mr Afid Nurkholis (Karst Research Group, Faculty of Geography, Indonesia)

Co-author

Dr Eko Haryono (Karst Research Group, Faculty of Geography, UGM)

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